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Physics High Energy Physics (Experiment)

hep-ex Watch High Energy Physics (Experiment)

Monday 10 August

High Energy Physics (Experiment)

Silent coverage failures in rare-event searches and a degeneracy index that predicts them

Davide Pagano

Searches for new physics in low-background experiments infer a non-negative signal strength from few events and often report an upper limit. Nominal frequentist coverage requires both a valid interval construction and an adequate data model. We study how controlled model departures affect lower- and upper-endpoint coverage for six interval procedures in an exact Poisson counting experiment, dark-matter recoil spectra, and a neutrinoless-double-beta-decay peak search. We introduce the Poisson–Fisher degeneracy index $\mathcal I_{\mathrm{PF}}(\delta\nu;\vartheta_0)=(\beta,\gamma)$, which maps a specified expected-count deformation, after projection onto the complete fitted tangent space, to $\beta$, the signed fitted signal shift in profiled standard-error units, and $\gamma$, the Poisson–Fisher norm of the unabsorbed residual. Locally, the sign of $\beta$ identifies the threatened endpoint, while larger $\gamma$ implies greater detectability by the saturated-Poisson goodness-of-fit test used here at a fixed $5\%$ type-I error rate. Across the studied deformations, positive signal-like bias degrades discovery-side coverage while making upper limits conservative; negative signal bias from overestimated signal efficiency can make the upper endpoint undercover. Calibration under the nominal simulator does not protect against misspecification of that simulator relative to the data-generating process. A plausible deformation with large $|\beta|$ and small $\gamma$ may therefore evade diagnosis and should be represented by a nuisance constrained with auxiliary information or included in a defensible envelope. In the exactly collinear constrained-nuisance benchmark, modelling the deformation restores coverage at the evaluated grid points, at a quantifiable cost in interval sensitivity.
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Sunday 9 August

High Energy Physics (Experiment) · Cross-listed from physics.data-an

Analytically Consistent Reconstruction of Finite Data Using Padé Sequences

Emerson Díaz, Balma Duch and Pere Masjuan

Reconstructing the analytic structure of a function from finite datasets is a fundamental problem across theoretical, numerical, and experimental physics. While Padé approximants provide a natural framework, finite-information effects, as well as statistical and systematic uncertainties, may obscure the underlying analytic structure and limit reconstruction reliability. In this work, we reinterpret the appearance of Froissart doublets not merely as numerical artifacts but as diagnostic objects carrying information about the analytic consistency of the input data. Accordingly, we develop a general Padé-based algorithm that exploits the dynamics of Froissart doublets along Padé sequences to identify localized inconsistencies and iteratively reconstruct the analytic structure most compatible with the data. The method requires no model for the origin of the inconsistencies and distinguishes genuine analytic features from spurious structures induced by finite-information effects. We validate it using Stieltjes functions, realistic pseudo-experimental datasets with statistical and systematic uncertainties, and general holomorphic functions. The complete algorithm is provided as a supplementary Mathematica notebook in an open GitLab repository.
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High Energy Physics (Experiment) · Cross-listed from hep-ph

Near-threshold resonances in $e^+e^-$ annihilation

S.G. Salnikov, A.E. Bondar and A.I. Milstein

Near-threshold resonances have been discovered in many hadron pair production processes, resulting in a significant increase in reaction cross sections at low relative velocities of the produced particles. The natural cause of such resonances is the interaction between slow hadrons in the final state. Our review demonstrates that, in virtually all known cases, final-state interactions successfully explain the results of numerous experiments demonstrating a nontrivial energy dependence of cross sections for processes near reaction thresholds. A comprehensive study of near-threshold resonances in various processes can provide new information about the interaction between hadrons at large distances.
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High Energy Physics (Experiment)

SuperEM: A Sub-meV Threshold Detector Architecture for Cosmic Neutrino Background and Dark Matter Detection

Zhenjie Li, Xilei Sun and Xiaoshan Jiang

Expanding the operational boundaries of radiation detection is imperative for contemporary particle physics, astrophysics, and cosmology. At this frontier, the direct detection of the Cosmic Neutrino Background (C$\nu$B), the determination of the absolute neutrino mass scale, and the search for sub-GeV Light Dark Matter (LDM) necessitate detector architectures capable of sub-millielectronvolt (sub-meV) energy thresholds, exceptional absolute energy resolution, fast time response, and massive scalability. Current technologies confront an intrinsic limit—the “impossible triangle”—wherein optimizing for sub-meV thresholds inherently compromises either macroscopic timing response or spatial scalability. Here, we introduce the Superconductor-Coupled Semiconductor Electron-Multiplying (SuperEM) detector, a fundamentally novel structural paradigm designed to bypass this limitation. The architecture couples the ultra-low energy threshold of a superconducting absorber with the intrinsic high-gain digitization of a strongly biased, high-density semiconductor P-N junction. Incident energy yields a proliferation of non-equilibrium quasiparticles, which are subsequently extracted via quantum tunneling across an ultra-thin Atomic Layer Deposition (ALD) insulating barrier. Building upon our prior empirical validation of deep-cryogenic avalanche mechanics, this manuscript establishes the fundamental theoretical feasibility and structural foundation of the complete device. Signal transport simulations confirm that an undoped interface coupled with a strong drift field enables highly efficient, nanosecond-scale transient electron drift, resolving completely within 35 ns. The SuperEM architecture thus constitutes a scalable, high-resolution, and fast time-response framework for next-generation C$\nu$B and LDM observatories.
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High Energy Physics (Experiment) · Cross-listed from hep-ph

QCD Sum Rule Analysis of Triply Heavy $(Q\bar{Q})(Q\bar{q})$ Tetraquark States with $J^P=0^{\pm}$

Wen-Shuai Zhang, Chun-Gui Duan, Zhi-Hui Guo et al. (+1 more)

Within the framework of QCD sum rules, we systematically investigate the mass spectra and possible decay patterns of the $(c\bar{c})(c\bar{q})$ and $(b\bar{b})(b\bar{q})$ tetraquark states with quantum numbers $J^{P}=0^{\pm}$. Based on two distinct color configurations, $[8_c]_{Q\bar{Q}} \otimes [8_c]_{Q\bar{q}}$ and $[1_c]_{Q\bar{Q}} \otimes [1_c]_{Q\bar{q}}$, we construct 18 interpolating currents for these states, and obtain stable sum rules for a subset of them. By calculating the corresponding two-point correlation functions, we extract their mass spectra. For the $(c\bar{c})(c\bar{q})$ system, we identify four possible tetraquark states: two with $J^{P}=0^+$, namely $T_{3c,0}(4760)$ and $T_{3c,0}(5000)$, and two with $J^{P}=0^-$, denoted as $T_{3c,0}(5040)$ and $T_{3c,0}(5370)$. For the $(b\bar{b})(b\bar{q})$ system, the extracted masses are found to lie in the ranges $13.72$–$14.02$ GeV for the $J^{P}=0^+$ states and $13.90$–$14.22$ GeV for the $J^{P}=0^-$ states. We further analyze their possible decay modes. Our results indicate that $T_{3c,0}(5000)$, $T_{3c,0}(5040)$, and $T_{3c,0}(5370)$ can decay into a charmonium state and a charmed meson, and are therefore expected to have appreciable decay widths. By contrast, $T_{3c,0}(4760)$ and all predicted $(b\bar{b})(b\bar{q})$ tetraquark states are expected to be relatively narrow, since the corresponding two-body strong decays via the fall-apart mechanism are kinematically forbidden. Therefore, $T_{3c,0}(4760)$ and all predicted $(b\bar{b})(b\bar{q})$ tetraquark states are promising candidates for experimental searches in final states containing a $D$ or a $\bar{B}$ meson, accompanied by light hadrons or a photon.
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All authors Wen-Shuai Zhang, Chun-Gui Duan, Zhi-Hui Guo, Liang Tang

Saturday 8 August

High Energy Physics (Experiment) · Cross-listed from hep-ph

Isospin and flavor SU(3) symmetry breaking in doubly heavy baryons

Ghil-Seok Yang, June-Young Kim and Hyun-Chul Kim

The recent observations of the $\Xi_{cc}^{+}$ and the $\Omega_{cc}^{+}$ by the LHCb Collaboration complete the ground-state triplet of doubly charmed baryons, so that its internal mass pattern can be used to test symmetry breaking in the light-quark sector. We study the doubly heavy baryons within the pion mean-field approach, regarding them as bound states of the $N_c-2$ valence light quarks that generate the pion mean field in the presence of a compact heavy diquark. All dynamical parameters for flavor SU(3) and isospin symmetry breaking were determined in the light and singly heavy baryon sectors, and the hyperfine coupling is fixed by the singly heavy spectrum. With the heavy-quark masses taken from the PDG values, the measured $\Xi_{cc}^{++}$ mass is used only to determine the collective rotational energy of the light subsystem, so that the mass splittings within the triplet are predictions. We obtain $M_{\Xi_{cc}^{+}}=(3620.17\pm13.08)$ MeV and $M_{\Omega_{cc}^{+}}=(3746.62\pm13.22)$ MeV. The predicted isospin splitting, $M_{\Xi_{cc}^{++}}-M_{\Xi_{cc}^{+}}=(1.43\pm0.38)$ MeV, is consistent with the LHCb observation of the $\Xi_{cc}^{+}$. We also present the masses of the spin-3/2 doubly charmed states and the doubly bottom spectrum.
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High Energy Physics (Experiment) · Cross-listed from hep-ph

Topological analysis of scale-invariant spatial fluctuations in ultrarelativistic heavy-ion collisions

Salman Khurshid Malik, Ramni Gupta, Fakhar Ul Haider et al. (+1 more)

The QGP-to-hadronic matter phase transition and QCD critical point in heavy-ion collisions can be identified by studying spatial fluctuations among final-state particles using intermittency analysis. First CMC-based intermittency analysis in the two-dimensional angular ($\eta$, $\varphi$) phase space, using EPOS as the background model is presented. Critical fluctuation signals are extremely weak, constituting only a few percent of the total event sample and are severely diluted by the overwhelming non-critical background, rendering traditional intermittency analyses insufficient for reliable signal extraction. To extract the weak critical signal, we employ a two-stage topological machine learning framework combining Topological Data Analysis (TDA) with deep learning. In the first stage, particle events are represented as two-dimensional point clouds and a Delaunay-based sub-level set filtration is constructed to extract Betti curves as multiscale topological invariants, corrected for multiplicity bias via azimuthal randomisation and classified by two complementary architectures, a TopoPointNet (TPN) and Boosted Decision Trees (BDT). Since event-level classification alone is insufficient to restore the critical scaling, a second stage applies a particle-level density filter, explicitly stripping away the diffuse thermal background and isolating the densely packed critical clusters. The two stage pipeline successfully restores the power-law scaling of the normalized factorial moments, enabling accurate recovery of the intermittency index in ($\eta$, $\varphi$) space and establishing topological machine learning as a robust data driven tool for probing the QCD critical point and the phase structure of strongly interacting matter in heavy-ion collisions at LHC energies.
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All authors Salman Khurshid Malik, Ramni Gupta, Fakhar Ul Haider, Balwan Singh

Friday 7 August

High Energy Physics (Experiment) · Cross-listed from astro-ph.CO

Axion dark matter search with a photonic bandgap cavity haloscope and dielectric tuning rod over 10.25-10.45 GHz

Morgan Lynn, Ankur Agrawal, Arjun Ghosh et al. (+4 more)

We report the development of a new widely tunable cavity and demonstrate its use in a search for dark matter axions. We achieve unloaded quality factors above $10^{5}$, roughly $25\times$ larger than a bare copper cavity at the same frequency, using concentric sapphire shells to reduce Ohmic losses on the cavity barrel. A rotating sapphire rod tunes our cavity mode over the $10.1-11.7$ GHz range, approximately $16\%$ of its resonant frequency. Using an amplified receiver chain, we demonstrate sensitivity to new axion parameter space by tuning the cavity over the $200$ MHz range between $10.25-10.45$ GHz (42.4 - 43.2, $\mu$eV) to constrain the axion-to-photon coupling to $|g_{a\gamma\gamma}|$ $\leq$ 1 $\times$ $10^{-12}$ ${GeV}^{-1}$. This cavity can scan its tuning range about $9$ times faster compared to a bare copper cavity when paired with a photon counting device, laying the groundwork for a definitive search for the QCD axion over $10.1-11.7$ GHz.
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All authors Morgan Lynn, Ankur Agrawal, Arjun Ghosh, Sara Sussman, Steven G. Johnson, David I. Schuster, Aaron S. Chou

High Energy Physics (Experiment) · Cross-listed from physics.ins-det

CMOS Image Sensors for CEvNS Detection at Nuclear Reactors

Santiago Ezequiel Perez, Dario Rodrigues and Miguel Sofo-Haro

In this work we present Complementary Metal-Oxide-Semiconductor (CMOS) Image Sensors (CIS) for reactor neutrino experiments targeting coherent elastic neutrino-nucleus scattering (CEvNS). We have developed an active-shielding strategy for physical background reduction along with an analytical model describing the impact of intrinsic detector backgrounds from dark current and readout noise at a given frame rate (fps). Assuming a conservative background of 100 DRU, and a feasible CIS-based detector with $\sim$100g of sensitive silicon mass, 1$e^-$ of readout noise, and 200fps, it can detect CEvNS in less than 50 days at 16 meters from a 3.6 GW thermal reactor core. Improving the detector performance to 0.2$e^-$ readout noise and 1000fps substantially reduces the detection time to about 7 days. These results establish CIS technology as a promising platform for reactor monitoring and precision neutrino measurements, with thick CMOS sensors featuring parallel and non-destructive readout emerging as particularly attractive candidates for next-generation CEvNS experiments.
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High Energy Physics (Experiment) · Cross-listed from hep-ph

Quest for an Understanding of Pion and Kaon Structure

Zhen-Ni Xu, Daniele Binosi, Craig D. Roberts et al. (+1 more)

The emergence of massless (Nambu-Goldstone) bosons in association with a dynamically global broken symmetry is a long known and widespread phenomenon in physics. However, practically nothing is known about the expressions of Nambu–Goldstone boson character on the internal structure of these bound states. Indeed, their structure is often ignored. In strong interactions, pions and kaons are the (would-be) Nambu-Goldstone bosons and experiments underway or planned at existing or anticipated high-energy, high-luminosity facilities will gather data that it is hoped will enable maps to be drawn of their internal structure. Meanwhile, theory and phenomenology find themselves in something of a quagmire. Herein, we provide a snapshot of the current status, highlighting issues under debate and identifying areas that deserve greater attention so that best use can be made of what is likely to be a huge volume of data delivered in the next decade or so.
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All authors Zhen-Ni Xu, Daniele Binosi, Craig D. Roberts, José Rodríguez-Quintero

High Energy Physics (Experiment)

Combination of Higgs boson measurements at $\sqrt{s} =$ 13 TeV and their interpretations by the ATLAS experiment

ATLAS Collaboration

This paper presents combined measurements of Higgs boson production and decay using up to 140 fb$^{-1}$ of proton–proton collision data collected by the ATLAS experiment at the LHC at $\sqrt{s} = 13$ TeV. The inclusive Higgs boson event rate relative to its Standard Model prediction is determined to be $0.990 ^{+0.053}_{-0.051} = 0.990 \pm 0.027 \text{ (stat.) } \pm 0.024 \text{ (exp.) } ^{+0.037}_{-0.035} \text{ (sig. theo.) } ^{+0.016}_{-0.015} \text{ (bkg. theo.)}$, separating statistical, experimental, signal-theory and background-theory uncertainty components. The signal theory uncertainty is the largest contribution, dominated by missing higher-order terms in QCD and the modelling of parton shower effects. Inclusive production cross-sections and decay branching ratios are measured, with sensitivities improved by up to 35% relative to the previous ATLAS publication. Production cross-sections for individual decay channels are also reported. The results are interpreted in terms of modifiers to Higgs boson couplings. The combination of single Higgs boson and Higgs boson pair production measurements yields $\kappa_\lambda = 1.3^{+3.1}_{-1.6}$ for the modifier to the Higgs boson self-coupling, with an interval of $[-1.5, 6.5]$ at 95% confidence level. The partial width in the $H\to b\bar{b}$ decay channel is used to obtain the first ATLAS determination of the running mass of the $b$-quark at the Higgs boson mass scale in the modified minimal subtraction scheme, found to be $m_b(m_H) = 2.73^{+0.27}_{-0.25}$ GeV. The total width of the Higgs boson is measured to be $\Gamma_H = 3.6^{+2.1}_{-1.6}$ MeV based on its on- and off-shell production rates. The kinematics of Higgs boson production are probed within the framework of Simplified Template Cross-sections in 44 kinematic regions, and the results are interpreted in the context of Standard Model Effective Field Theory models.
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High Energy Physics (Experiment) · Cross-listed from hep-ph

Chiral Doubling of Heavy-Light Hadrons and the New Beauty–Strange $B_{s0}^*(5700)^0$ Candidate

Maciej A. Nowak and Ismail Zahed

The recent observation by the LHCb Collaboration of a new beauty–strange meson $B_{s0}^*(5700)^0$~\cite{LHCb:2026Bs0star}, under the conditional assignment $J^P=0^+$ provides an important new test of the chiral organization of heavy-light hadrons. More than three decades ago it was proposed that the coexistence of heavy-quark spin symmetry and spontaneously broken chiral symmetry implies that every heavy-light spin multiplet should possess an opposite-parity partner separated by a nearly universal mass gap determined primarily by the dynamics of the light degrees of freedom~\cite{Nowak:1993vc,Bardeen:1993ae}. This chiral doubling scenario was later developed into a quantitative heavy-hadron effective theory and extended to the complete charm and beauty spectra. In particular, the strange beauty sector was predicted to exhibit a parity splitting closely related to that of the strange charm sector, with only small $1/m_Q$ corrections. We briefly review the symmetry origin of chiral doubling, derive the universal parity splitting through the heavy-hadron chiral effective theory, and discuss the new LHCb observation in the context of the original theoretical predictions. Taken together with the established charm spectrum, if the new beauty-strange state is confirmed to have $J^P=0^+$, its mass is consistent with its interpretation as the chiral partner of the ground state $B_s^0$. Finally, we stress that the above confirmation of the spin and parity imposes in the chiral doubling scenario an existence of yet unobserved, very narrow beauty-strange meson with assignment $1^+$ at 5747 $\pm$ 2 MeV. This work is dedicated to the memory of our friend and collaborator Mannque Rho (1936–2026).
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High Energy Physics (Experiment) · Cross-listed from hep-ph

Axion Dark Matter Modulated Spin Wave Interferometry

Jiayi Liu, Chen-Hui Xie, Runyu Lei et al. (+3 more)

We propose a novel asymmetric spin wave interferometer to detect ultralight axion dark matter. The axion modulates spin-wave properties via a weak effective magnetic field in ferromagnets. The interferometer splits a spin-wave source into two paths of different lengths and sets them to interfere destructively. The system then converts the axion-induced phase shift into a measurable magnetization oscillation that can radiate electromagnetic waves and generate electrical signals via Faraday induction. The signal-to-noise ratios have been evaluated for three detection schemes: the linear amplifier, the single-photon detector, and the electrical signal detection approach, accounting for both magnetization fluctuation and thermal noise. The accessible axion mass range is approximately $10^{-8}$ eV to $10^{-6}$ eV, set by the spin wave propagation length and the relaxation time.
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All authors Jiayi Liu, Chen-Hui Xie, Runyu Lei, Sichun Sun, Yu Gao, Jinxing Zhang

High Energy Physics (Experiment) · Cross-listed from physics.ins-det

A compact beta particle momentum detector

D. Kodroff, M. Hu, K. Adcock et al. (+8 more)

We present the design, development, and first calibration results of a compact beta electron detector for the Quantum Invisible Particle Sensor (QuIPS) experiment. The QuIPS electron detector is designed to reconstruct the full momentum vector of $\beta$ particles emitted from radioisotope-doped optically levitated nanospheres in ultra-high vacuum (UHV), enabling a measurement of the neutrino momentum and a search for heavy sterile neutrinos. The detector comprises two thinned CMOS detectors for directional tracking and a plastic scintillator read out by silicon photomultipliers (SiPMs) for calorimetry. The entire assembly must operate inside an existing optical trapping vacuum chamber at pressures below $10^{-7}$ mbar, imposing stringent constraints on material selection, power dissipation, outgassing, and compactness. We demonstrate sensitivity to $\beta$-decay electrons with energies as low as 100 keV and a detection efficiency of 35% above 500 keV, the primary window of interest for a heavy sterile neutrino search. The CMOS tracker resolves the momentum direction at the mrad scale and reconstructs the $\beta$ emission vertex with sub-mm precision, while the scintillator-SiPM system achieves an energy resolution of 5% at 1 MeV.
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All authors D. Kodroff, M. Hu, K. Adcock, R. Carney, P. Denes, M. Garcia-Sciveres, A. Goldschmidt, V. Gomez, P. Sorensen, T. Villabona, D. Carney

Thursday 6 August

High Energy Physics (Experiment)

Estimating the sensitivity of the IceCube Upgrade to probe the interior of the Earth using atmospheric neutrino oscillations

The IceCube Collaboration: R. Abbasi, M. Ackermann, J. Adams et al. (+420 more)

The IceCube Upgrade is a densely instrumented central region of the IceCube Neutrino Observatory, deployed during the 2025-26 polar season. It will reduce the detector's energy threshold and improve overall reconstruction capabilities for multi-GeV atmospheric neutrinos, which in turn enhance their sensitivity to Earth matter effects as they traverse through the deep Earth. In this study, we describe the potential of the IceCube Upgrade to observe Earth matter effects on atmospheric neutrinos and estimate the detector's sensitivity to probe key features of the Preliminary Reference Earth Model by utilizing these observations. We highlight the IceCube Upgrade's capability to estimate the mass of the Earth and verify the non-homogeneous distribution of matter density within the Earth. We also estimate the IceCube Upgrade sensitivity to measure the correlated densities of the Earth layers while incorporating constraints from the mass and moment of inertia of the Earth. Neutrino-based results would be independent and complementary to the seismic and gravitational measurements.
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All authors The IceCube Collaboration: R. Abbasi, M. Ackermann, J. Adams, S. K. Agarwalla, J. A. Aguilar, M. Ahlers, J.M. Alameddine, S. Ali, N. M. Amin, K. Andeen, C. Argüelles, S. Athanasiadou, S. N. Axani, R. Babu, X. Bai, A. Balagopal V., S. W. Barwick, V. Basu, R. Bay, J. J. Beatty, J. Becker Tjus, P. Behrens, J. Beise, C. Bellenghi, S. Benkel, S. BenZvi, D. Berley, E. Bernardini, D. Z. Besson, E. Blaufuss, L. Bloom, S. Blot, F. Bontempo, J. Y. Book Motzkin, C. Boscolo Meneguolo, S. Böser, O. Botner, J. Böttcher, J. Braun, B. Brinson, Z. Brisson-Tsavoussis, L. Brusa, R. T. Burley, D. Butterfield, K. Carloni, J. Carpio, S. Chattopadhyay, N. Chau, Y. C. Chen, Z. Chen, D. Chirkin, S. Choi, A. Chubarov, B. A. Clark, D. A. Coloma Borja, A. Connolly, J. M. Conrad, D. F. Cowen, C. De Clercq, J. J. DeLaunay, D. Delgado, T. Delmeulle, S. Deng, P. Desiati, K. D. de Vries, G. de Wasseige, T. DeYoung, J. C. Díaz-Vélez, S. DiKerby, T. Ding, M. Dittmer, A. Domi, L. Draper, L. Dueser, D. Durnford, K. Dutta, M. A. DuVernois, T. Ehrhardt, L. Eidenschink, A. Eimer, C. Eldridge, P. Eller, E. Ellinger, D. Elsässer, R. Engel, H. Erpenbeck, W. Esmail, S. Eulig, J. Evans, P. A. Evenson, K. L. Fan, K. Fang, K. Farrag, A. Fattorini, A. R. Fazely, A. Fedynitch, N. Feigl, C. Finley, D. Fox, A. Franckowiak, S. Fukami, P. Fürst, J. Gallagher, E. Ganster, A. Garcia, M. Garcia, E. Genton, L. Gerhardt, A. Ghadimi, C. Glaser, T. Glüsenkamp, J. G. Gonzalez, S. Goswami, A. Granados, D. Grant, S. J. Gray, S. Griffin, S. Griswold, K. M. Groth, D. Guevel, C. Günther, P. Gutjahr, C. Ha, A. Hallgren, L. Halve, F. Halzen, L. Hamacher, M. Handt, K. Hanson, J. Hardin, A. A. Harnisch, P. Hatch, A. Haungs, J. Häußler, K. Helbing, J. Hellrung, B. Henke, L. Hennig, F. Henningsen, L. Heuermann, R. Hewett, N. Heyer, S. Hickford, A. Hidvegi, C. Hill, G. C. Hill, R. Hmaid, K. D. Hoffman, A. Hollnagel, D. Hooper, S. Hori, K. Hoshina, M. Hostert, W. Hou, M. Hrywniak, T. Huber, K. Hultqvist, K. Hymon, A. Ishihara, W. Iwakiri, M. Jacquart, S. Jain, O. Janik, M. Jansson, M. Jin, N. Kamp, D. Kang, W. Kang, A. Kappes, L. Kardum, T. Karg, A. Karle, A. Katil, M. Kauer, J. L. Kelley, M. Khanal, A. Khatee Zathul, A. Kheirandish, T. Kim, H. Kimku, F. Kirchner, J. Kiryluk, C. Klein, Y. Kobayashi, S. Koch, A. Kochocki, R. Koirala, H. Kolanoski, T. Kontrimas, L. Köpke, C. Kopper, D. J. Koskinen, P. Koundal, M. Kowalski, T. Kozynets, A. Kravka, N. Krieger, J. Krishnamoorthi, T. Krishnan, K. Kruiswijk, E. Krupczak, A. Kumar, E. Kun, N. Kurahashi, C. Lagunas Gualda, L. Lallement Arnaud, M. J. Larson, F. Lauber, J. P. Lazar, K. Leonard DeHolton, A. Leszczyńska, C. Li, J. Liao, C. Lin, Q. R. Liu, Y. T. Liu, M. Liubarska, C. Love, L. Lu, F. Lucarelli, W. Luszczak, Y. Lyu, M. Macdonald, E. Magnus, Y. Makino, E. Manao, S. Mancina, A. Mand, I. C. Mariş, S. Marka, Z. Marka, L. Marten, I. Martinez-Soler, R. Maruyama, J. Mauro, F. Mayhew, F. McNally, K. Meagher, A. Medina, M. Meier, Y. Merckx, L. Merten, J. Mitchell, L. Molchany, S. Mondal, T. Montaruli, R. W. Moore, Y. Morii, A. Mosbrugger, D. Mousadi, E. Moyaux, T. Mukherjee, M. Nakos, U. Naumann, R. Neshat, L. Neste, M. Neumann, H. Niederhausen, M. U. Nisa, K. Noda, A. Noell, A. Novikov, A. Obertacke, V. O'Dell, A. Olivas, R. Orsoe, J. Osborn, E. O'Sullivan, B. Owens, V. Palusova, H. Pandya, A. Parenti, C. Parisel, N. Park, V. Parrish, E. N. Paudel, L. Paul, T. Pernice, T. C. Petersen, J. Peterson, S. Pick, M. Plum, A. Pontén, V. Poojyam, B. Pries, R. Procter-Murphy, G. T. Przybylski, L. Pyras, C. Raab, J. Rack-Helleis, N. Rad, M. Ravn, K. Rawlins, Z. Rechav, A. Rehman, I. Reistroffer, E. Resconi, C. D. Rho, W. Rhode, L. Ricca, B. Riedel, A. Rifaie, E. J. Roberts, S. Rodan, M. Rongen, A. Rosted, C. Rott, T. Ruhe, L. Ruohan, D. Ryckbosch, J. Saffer, D. Salazar-Gallegos, P. Sampathkumar, A. Sandrock, G. Sanger-Johnson, M. Santander, S. Sarkar, M. Scarnera, M. Schaufel, H. Schieler, S. Schindler, L. Schlickmann, B. Schlüter, F. Schlüter, N. Schmeisser, T. Schmidt, F. Schmitt, A. Scholz, F. G. Schröder, S. Schwirn, S. Sclafani, D. Seckel, L. Seen, M. Seikh, S. Seunarine, P. A. Sevle Myhr, R. Shah, S. Shah, S. Shefali, N. Shimizu, M. Shin, B. Skrzypek, R. Snihur, J. Soedingrekso, D. Soldin, P. Soldin, G. Sommani, D. Song, C. Spannfellner, G. M. Spiczak, C. Spiering, J. Stachurska, M. Stamatikos, T. Stanev, T. Stezelberger, T. Stürwald, T. Stuttard, G. W. Sullivan, I. Taboada, S. Ter-Antonyan, A. Terliuk, A. Thakuri, M. Thiesmeyer, W. G. Thompson, J. Thwaites, W. Tian, S. Tilav, K. Tollefson, J. A. Torres, S. Toscano, D. Tosi, A. K. Upadhyay, K. Upshaw, A. Vaidyanathan, N. Valtonen-Mattila, J. Valverde, J. Vandenbroucke, T. Van Eeden, N. van Eijndhoven, L. Van Rootselaar, J. van Santen, J. Vara, F. Varsi, M. Velazquez, M. Venugopal, M. Vereecken, S. Vergara Carrasco, S. Verpoest, D. Veske, A. Vijai, J. Villarreal, C. Walck, A. Wang, E. H. S. Warrick, C. Weaver, A. Weindl, J. Weldert, A. Y. Wen, C. Wendt, J. Werthebach, M. Weyrauch, N. Whitehorn, C. H. Wiebusch, D. R. Williams, L. Witthaus, J. Woodward, G. Wrede, X. W. Xu, J. P. Yanez, Y. Yao, E. Yildizci, S. Yoshida, F. Yu, S. Yu, T. Yuan, S. Yun-Cárcamo, A. Zander Jurowitzki, A. Zegarelli, S. Zhang, Z. Zhang, P. Zhelnin, P. Zilberman, C. Zilleruelo Cañas

High Energy Physics (Experiment) · Cross-listed from physics.ins-det

Gamma Neutron Radioactive Source Identification in Water Cherenkov Detectors

A. Núñez Selin, C. Sarmiento Cano, H. Asorey et al. (+1 more)

Water Cherenkov Detectors (WCDs) are a robust technology widely used in astrophysics, high energy physics, and recently nuclear security applications. They detect high energy interactions through the Cherenkov light emitted by charged particles traveling faster than the speed of light in water. In this work, we demonstrate the feasibility of gamma-neutron discrimination in WCDs using a combined methodology that integrates statistical analysis with machine learning techniques. The experimental setup employs different shielding configurations to isolate gamma and neutron contributions from a \textsuperscript{241}AmBe source, while \textsuperscript{60}Co and \textsuperscript{137}Cs sources are used to establish a signal to energy calibration. A statistical analysis based on a $3\sigma$ significance criterion is used to define energy thresholds, enabling a linear relationship between the measured charge spectrum and the deposited energy. Building on this calibration, pulse shape information is further exploited through machine learning methods to improve event classification. An ensemble model based on a soft-voting strategy combining a Bagging classifier, CatBoost, and a Multilayer Perceptron was trained on detector signals acquired under different shielding conditions, achieving an accuracy of 0.816 and an area under the Receiver Operating Characteristic (ROC) curve. The combined approach demonstrates that statistical thresholding provides a physically grounded discrimination baseline across the full energy range, while machine learning enhances classification performance at higher energies by leveraging pulse level information. This integrated strategy improves radiation identification capabilities in water Cherenkov detectors, with potential applications in nuclear security and radiation detection.
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All authors A. Núñez Selin, C. Sarmiento Cano, H. Asorey, I. Sidelnik

High Energy Physics (Experiment) · Cross-listed from nucl-ex

The Super Bigbite Spectrometer physics program

B. Wojtsekhowski and G. Cates

The structure of the nucleon is a central problem in strong interaction physics in the non-perturbative regime. Indeed, the vast majority of the known matter in the Universe is made of protons and neutrons which are a remarkable emergent phenomenon of quantum chromodynamics. A critical aspect of investigating nucleon structure experimentally is the measurement of fundamental quantities such the elastic nucleon form factors. Also important is the measurement transverse momentum dependent distribution functions. Accessing such quantities experimentally, however, is challenging because of the small cross sections involved, particularly at high momentum transfer. We present here a physics program that is addressing this challenge based on the Super Bigbite Spectrometer (SBS) that has recently been built at the Thomas Jefferson National Accelerator Facility. SBS provides a relatively large solid angle of 70 msr and can be used at high luminosities and forward-scattering angles. It is based on a single large dipole magnet in an open-geometry in which the detector package has a direct line of sight to the target. This approach is only possible through the use of detector technology that can operate at very high rates while providing excellent spatial resolution. It is the product of solid angle and luminosity that is critical when measuring small cross sections, and in this regard, among spectrometer systems at JLab, SBS is presently unique in its capability. The first set of experiments utilizing SBS has been successfully completed, and more experiments are planned for the future. We also discuss a proposed upgrade that would increase the SBS solid angle to 260 msr, thereby opening perspectives for an even broader physic program.
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High Energy Physics (Experiment) · Cross-listed from hep-ph

Oscillating Neutrinos vs. Oscillating Scalars: Constraining Scalar Dark Matter-Induced Neutrino Mass

Kierthika Chathirathas, Sabya Sachi Chatterjee and Thomas Schwetz

We consider the hypothesis that neutrino masses are generated by a coupling to an ultra-light (pseudo-)scalar field, which provides the dark matter in the universe. This leads to time-varying neutrino masses with a frequency set by the dark matter mass, with implications for neutrino oscillation data. We use that dark matter is in a virialised state in the galaxy and provide a detailed discussion of the relevant time scales. Using data from the T2K, RENO and JUNO experiments, we show that for dark matter masses smaller than about $3\times 10^{-8}$eV down to the smallest allowed dark matter mass of about $10^{-21}$eV only a fraction of between 9% to 54% of the total neutrino mass can arise from the coupling to the background scalar, depending on the value of the scalar mass. Future data from JUNO may improve these limits down to 1% in certain regions of scalar masses. We focus on a real scalar field, but most of our results hold also for a complex scalar.
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High Energy Physics (Experiment)

Quantum noise reduction schemes for KAGRA post-O5 upgrade

Yuhang Zhao, Marc Eisenmann, Michael Page et al. (+1 more)

Quantum noise, arising from the quantisation of electromagnetic field, has been a limiting noise source for current gravitational wave (GW) detectors. Squeezed vacuum modifies quantum fluctuations and has been routinely employed. To reduce quantum noise, the current solution is to combine squeezed vacuum with a detuned over-coupled optical cavity (filter cavity) to achieve frequency-dependent squeezing (FDS). The sensitivity to GW signals can be decomposed into a noise budget. Depending on the detector configuration, the contribution from noise sources other than quantum noise can be significant. In particular, suspension noise from multi-stage pendulums is a key factor in quantum-noise reduction design. In the context of KAGRA post-O5, we have compared quantum noise reduction schemes, frequency-independent squeezing (FIS), FDS with a filter cavity (FC), FDS with an amplitude filter cavity (AFC), FDS with a frequency-dependent beam splitter (FDBS) and EPR scheme. The FC scheme was found to outperform the AFC and FDBS schemes at all frequencies. It was found that FIS scheme gives the largest Binary Neutron Star (BNS) range when low frequency noise is dominated by classical noise, while the FC scheme gives the largest BNS range when low-frequency noise becomes dominated by quantum noise. Optimised filter cavity parameters could substantially improve the BNS range. This would allow at least 23% increase in the detection rate for an 85 m filter cavity, compared with using FIS scheme. Once a filter cavity is constructed with optimised parameters, refining its detuning can fully compensate for the variations in arm power (from half to full design value) and for different intra-cavity loss conditions. The EPR scheme performs best for the detection of heavy binary systems.
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All authors Yuhang Zhao, Marc Eisenmann, Michael Page, Zong-Hong Zhu

High Energy Physics (Experiment) · Cross-listed from astro-ph.HE

Search for an all-sky and a Galactic Ridge diffuse neutrino emission with the first 2 years of KM3NeT/ARCA data

The KM3NeT Collaboration

We report on the search performed for a diffuse astrophysical neutrino flux from the full sky and from a specific region of the Galactic plane, the Galactic Ridge. The study uses the dataset collected with the first KM3NeT/ARCA configurations with 6, 8, 19, and 21 active detection units, corresponding to a total livetime of 640 days. For the all-sky analysis, the fitted single-flavour astrophysical neutrino flux parameters, under the single power-law assumption, are $\phi_0^{1f} = 3.0^{+2.1}_{-2.0} \times 10^{-18}$ GeV$^{-1}$ cm$^{-2}$ s$^{-1}$ sr$^{-1}$ with spectral index $\gamma = 3.00^{+0.30}_{-0.35}$ at 68% credible level. The Galactic Ridge fit does not yield constraints for the flux parameters with the current sensitivity. For both analyses upper limits are derived and compared with state-of-the-art measurements. While the analysis of these datasets has not yielded statistically significant results, the developed methods provide a solid basis for future measurements with the KM3NeT detector.
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High Energy Physics (Experiment)

Search for the charged lepton flavour violating decay $\eta'\to e\mu$

BESIII Collaboration: M. Ablikim, M. N. Achasov, P. Adlarson et al. (+765 more)

Based on $(8998\pm40)\times10^6$ $J/\psi$ events collected in $e^+e^-$ collisions at $\sqrt{s} = 3.097$ GeV with the BESIII detector, we present a search for the charged lepton flavour violating decay $\eta'\to e\mu$ with $J/\psi\to\gamma\eta'$. No significant signal is observed, and an upper limit on its decay branching fraction is set to be $6.3\times10^{-7}$ at the 90% confidence level, improving the previous best result by nearly three orders of magnitude.
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All authors BESIII Collaboration: M. Ablikim, M. N. Achasov, P. Adlarson, X. C. Ai, C. S. Akondi, R. Aliberti, A. Amoroso, Q. An, Y. H. An, M. S. Anderson, Y. Bai, O. Bakina, H. R. Bao, X. L. Bao, M. Barbagiovanni, V. Batozskaya, K. Begzsuren, N. Berger, M. Berlowski, M. B. Bertani, D. Bettoni, F. Bianchi, E. Bianco, A. Bortone, I. Boyko, R. A. Briere, A. Brueggemann, D. Cabiati, H. Cai, M. H. Cai, X. Cai, A. Calcaterra, G. F. Cao, N. Cao, S. A. Cetin, X. Y. Chai, J. F. Chang, T. T. Chang, G. R. Che, Y. Z. Che, C. H. Chen, Chao Chen, G. Chen, H. S. Chen, H. Y. Chen, M. L. Chen, S. J. Chen, S. M. Chen, T. Chen, W. Chen, X. R. Chen, X. T. Chen, X. Y. Chen, Y. B. Chen, Y. Q. Chen, Z. K. Chen, J. Cheng, L. N. Cheng, S. K. Choi, X. Chu, G. Cibinetto, F. Cossio, J. Cottee-Meldrum, H. L. Dai, J. P. Dai, X. C. Dai, A. Dbeyssi, R. E. de Boer, D. Dedovich, C. Q. Deng, Z. Y. Deng, A. Denig, I. Denisenko, M. Destefanis, F. De Mori, E. Di Fiore, X. X. Ding, Y. Ding, Y. X. Ding, J. Dong, L. Y. Dong, M. Y. Dong, X. Dong, Z. J. Dong, M. C. Du, S. X. Du, Shaoxu Du, X. L. Du, Y. Q. Du, Y. Y. Duan, Z. H. Duan, P. Egorov, G. F. Fan, J. J. Fan, Y. H. Fan, J. Fang, Jin Fang, S. S. Fang, W. X. Fang, Y. Q. Fang, L. Fava, F. Feldbauer, G. Felici, C. Q. Feng, J. H. Feng, Q. X. Feng, Y. T. Feng, M. Fritsch, C. D. Fu, J. L. Fu, Y. W. Fu, H. Gao, Xu Gao, Y. Gao, Y. N. Gao, Y. Y. Gao, Yunong Gao, Z. Gao, S. Garbolino, I. Garzia, L. Ge, P. T. Ge, Z. W. Ge, C. Geng, A. Gilman, K. Goetzen, J. Gollub, J. B. Gong, J. D. Gong, L. Gong, W. X. Gong, W. Gradl, M. Greco, M. D. Gu, M. H. Gu, C. Y. Guan, A. Q. Guo, H. Guo, J. N. Guo, L. B. Guo, M. J. Guo, R. P. Guo, X. Guo, Y. P. Guo, Z. Guo, A. Guskov, J. Gutierrez, J. Y. Han, T. T. Han, X. Han, F. Hanisch, K. D. Hao, X. Q. Hao, F. A. Harris, C. Z. He, K. K. He, K. L. He, F. H. Heinsius, C. H. Heinz, Y. K. Heng, C. Herold, P. C. Hong, G. Y. Hou, X. T. Hou, Y. R. Hou, Z. L. Hou, H. M. Hu, J. F. Hu, Q. P. Hu, S. L. Hu, T. Hu, Y. Hu, Y. X. Hu, Z. M. Hu, G. S. Huang, K. X. Huang, L. Q. Huang, P. Huang, X. T. Huang, Y. P. Huang, Y. S. Huang, T. Hussain, N. H\üsken, N. in der Wiesche, J. Jackson, Q. Ji, Q. P. Ji, W. Ji, X. B. Ji, X. L. Ji, Y. Y. Ji, L. K. Jia, X. Q. Jia, D. Jiang, S. J. Jiang, X. S. Jiang, Y. Jiang, J. B. Jiao, J. K. Jiao, Z. Jiao, L. C. L. Jin, S. Jin, Y. Jin, M. Q. Jing, X. M. Jing, T. Johansson, S. Kabana, X. L. Kang, X. S. Kang, B. C. Ke, V. Khachatryan, A. Khoukaz, O. B. Kolcu, B. Kopf, L. Kr\öger, L. Kr\ümmel, Y. Y. Kuang, X. Kui, N. Kumar, A. Kupsc, W. K\ühn, Q. Lan, W. N. Lan, T. T. Lei, M. Lellmann, T. Lenz, C. Li, C. H. Li, C. K. Li, Chunkai Li, Cong Li, D. M. Li, F. Li, G. Li, H. B. Li, H. J. Li, H. L. Li, H. N. Li, H. P. Li, Hui Li, J. N. Li, J. S. Li, J. W. Li, K. Li, K. L. Li, L. J. Li, L. K. Li, Lei Li, M. H. Li, M. R. Li, M. T. Li, P. L. Li, P. R. Li, Q. M. Li, Q. X. Li, R. Li, S. Li, S. X. Li, S. Y. Li, Shanshan Li, T. Li, T. Y. Li, W. D. Li, W. G. Li, X. Li, X. H. Li, X. K. Li, X. L. Li, X. Y. Li, X. Z. Li, Y. Li, Y. H. Li, Y. B. Li, Y. C. Li, Y. G. Li, Y. P. Li, Z. H. Li, Z. J. Li, Z. L. Li, Z. X. Li, Z. Y. Li, C. Liang, H. Liang, Y. F. Liang, Y. T. Liang, Z. Z. Liang, G. R. Liao, L. B. Liao, M. H. Liao, Y. P. Liao, J. Libby, A. Limphirat, C. C. Lin, C. X. Lin, D. X. Lin, T. Lin, B. J. Liu, B. X. Liu, C. Liu, C. X. Liu, F. Liu, F. H. Liu, Feng Liu, G. M. Liu, H. Liu, H. B. Liu, H. M. Liu, Huihui Liu, J. B. Liu, J. J. Liu, K. Liu, K. Y. Liu, Ke Liu, Kun Liu, L. Liu, L. C. Liu, Lu Liu, M. H. Liu, P. L. Liu, Q. Liu, S. B. Liu, T. Liu, W. M. Liu, W. T. Liu, X. Liu, X. K. Liu, X. L. Liu, X. P. Liu, X. T. Liu, X. Y. Liu, Y. Liu, Y. B. Liu, Yi Liu, Z. A. Liu, Z. D. Liu, Z. L. Liu, Z. Q. Liu, Z. X. Liu, Z. Y. Liu, X. C. Lou, H. J. Lu, J. G. Lu, X. L. Lu, Y. Lu, Y. H. Lu, Y. P. Lu, Z. H. Lu, C. L. Luo, J. R. Luo, J. S. Luo, M. X. Luo, T. Luo, X. L. Luo, Z. Y. Lv, X. R. Lyu, Y. F. Lyu, Y. H. Lyu, F. C. Ma, H. L. Ma, Heng Ma, J. L. Ma, L. L. Ma, L. R. Ma, Q. M. Ma, R. Q. Ma, R. Y. Ma, T. Ma, X. T. Ma, X. Y. Ma, F. E. Maas, I. MacKay, M. Maggiora, S. Maity, S. Malde, L. M. Mansur, Y. J. Mao, Z. P. Mao, S. Marcello, A. Marshall, F. M. Melendi, Y. H. Meng, Z. X. Meng, G. Mezzadri, H. Miao, T. J. Min, R. E. Mitchell, X. H. Mo, B. Moses, N. Yu. Muchnoi, J. Muskalla, Y. Nefedov, F. Nerling, H. Neuwirth, Z. Ning, S. Nisar, Q. L. Niu, W. D. Niu, Y. Niu, C. Normand, S. L. Olsen, Q. Ouyang, I. V. Ovtin, S. Pacetti, Y. Pan, A. Pathak, Y. P. Pei, M. Pelizaeus, G. L. Peng, H. P. Peng, X. J. Peng, Y. Y. Peng, K. Peters, K. Petridis, J. L. Ping, R. G. Ping, S. Plura, V. Prasad, L. P\öpping, F. Z. Qi, H. R. Qi, S. Qian, W. B. Qian, C. F. Qiao, J. H. Qiao, J. J. Qin, J. L. Qin, L. Q. Qin, L. Y. Qin, P. B. Qin, X. P. Qin, X. S. Qin, Z. H. Qin, J. F. Qiu, Z. H. Qu, J. Rademacker, K. Ravindran, C. F. Redmer, A. Rivetti, M. Rolo, G. Rong, S. S. Rong, F. Rosini, Ch. Rosner, M. Q. Ruan, W. R. Ruangyoo, N. Salone, A. Sarantsev, Y. Schelhaas, M. Schernau, K. Schoenning, M. Scodeggio, W. Shan, X. Y. Shan, Z. J. Shang, J. F. Shangguan, L. G. Shao, M. Shao, C. P. Shen, H. F. Shen, W. H. Shen, X. Y. Shen, B. A. Shi, Ch. Y. Shi, H. Shi, J. L. Shi, J. Y. Shi, M. H. Shi, S. Y. Shi, X. Shi, H. L. Song, J. J. Song, M. H. Song, T. Z. Song, W. M. Song, Y. X. Song, Zirong Song, S. Sosio, S. Spataro, S. Stansilaus, F. Stieler, M. Stolte, S. S Su, G. B. Sun, G. X. Sun, H. Sun, H. K. Sun, J. F. Sun, K. Sun, L. Sun, R. Sun, S. S. Sun, T. Sun, W. Y. Sun, Y. C. Sun, Y. H. Sun, Y. J. Sun, Y. Z. Sun, Z. Q. Sun, Z. T. Sun, H. Tabaharizato, N. T. Tagsinsit, C. J. Tang, G. Y. Tang, J. Tang, J. J. Tang, L. F. Tang, Y. A. Tang, Z. H. Tang, L. Y. Tao, M. Tat, J. X. Teng, J. Y. Tian, W. H. Tian, Y. Tian, Z. F. Tian, K. Yu. Todyshev, I. Uman, E. van der Smagt, B. Wang, Bin Wang, Bo Wang, C. Wang, Chao Wang, Cong Wang, D. Y. Wang, F. K. Wang, H. J. Wang, H. R. Wang, J. Wang, J. J. Wang, J. P. Wang, K. Wang, L. L. Wang, L. W. Wang, M. Wang, Mi Wang, N. Y. Wang, P. Wang, S. Wang, Shun Wang, T. Wang, W. Wang, W. P. Wang, X. F. Wang, X. L. Wang, X. N. Wang, Xin Wang, Y. Wang, Y. D. Wang, Y. F. Wang, Y. H. Wang, Y. J. Wang, Y. L. Wang, Y. N. Wang, Yanning Wang, Yaqian Wang, Yi Wang, Yuan Wang, Z. Wang, Z. L. Wang, Z. Q. Wang, Z. Y. Wang, Zhi Wang, Ziyi Wang, D. Wei, D. H. Wei, D. J. Wei, H. R. Wei, F. Weidner, H. R. Wen, S. P. Wen, U. Wiedner, G. Wilkinson, J. F. Wu, L. H. Wu, L. J. Wu, Lianjie Wu, S. G. Wu, S. M. Wu, X. W. Wu, Z. Wu, H. L. Xia, L. Xia, B. H. Xiang, D. Xiao, G. Y. Xiao, H. Xiao, Y. L. Xiao, Z. J. Xiao, C. Xie, K. J. Xie, Y. Xie, Y. G. Xie, Y. H. Xie, Z. P. Xie, T. Y. Xing, D. B. Xiong, G. F. Xu, H. Y. Xu, Q. J. Xu, Q. N. Xu, T. D. Xu, X. P. Xu, Y. Xu, Y. C. Xu, Z. S. Xu, F. Yan, L. Yan, W. B. Yan, W. C. Yan, W. H. Yan, W. P. Yan, X. Q. Yan, Y. Y. Yan, H. J. Yang, H. L. Yang, H. X. Yang, J. H. Yang, R. J. Yang, X. Y. Yang, Y. Yang, Y. G. Yang, Y. H. Yang, Y. M. Yang, Y. Q. Yang, Y. Z. Yang, Youhua Yang, Z. Y. Yang, W. J. Yao, Z. P. Yao, M. Ye, M. H. Ye, Z. J. Ye, K. Yi, Junhao Yin, Z. Y. You, B. X. Yu, C. X. Yu, G. Yu, J. S. Yu, L. W. Yu, T. Yu, X. D. Yu, Y. C. Yu, Yongchao Yu, C. Z. Yuan, H. Yuan, J. Yuan, Jie Yuan, L. Yuan, M. K. Yuan, S. H. Yuan, Y. Yuan, C. X. Yue, Ying Yue, A. A. Zafar, F. R. Zeng, S. H. Zeng, X. Zeng, Y. J. Zeng, Yujie Zeng, Y. C. Zhai, Y. H. Zhan, B. L. Zhang, B. X. Zhang, D. H. Zhang, G. Y. Zhang, Gengyuan Zhang, H. Zhang, H. C. Zhang, H. H. Zhang, H. Q. Zhang, H. R. Zhang, H. Y. Zhang, Han Zhang, J. Zhang, J. J. Zhang, J. L. Zhang, J. Q. Zhang, J. S. Zhang, J. W. Zhang, J. X. Zhang, J. Y. Zhang, J. Z. Zhang, Jianyu Zhang, Jin Zhang, Jiyuan Zhang, L. M. Zhang, Lei Zhang, N. Zhang, P. Zhang, Q. Zhang, Q. Y. Zhang, Q. Z. Zhang, R. Y. Zhang, S. H. Zhang, S. N. Zhang, Shulei Zhang, X. M. Zhang, X. Y. Zhang, Y. T. Zhang, Y. H. Zhang, Y. P. Zhang, Yao Zhang, Yu Zhang, Yu Zhang, Z. Zhang, Z. D. Zhang, Z. H. Zhang, Z. L. Zhang, Z. X. Zhang, Z. Y. Zhang, Zh. Zh. Zhang, Zhilong Zhang, Ziyang Zhang, Ziyu Zhang, G. Zhao, J.-P. Zhao, J. Y. Zhao, J. Z. Zhao, L. Zhao, Lei Zhao, M. G. Zhao, R. P. Zhao, S. J. Zhao, Y. B. Zhao, Y. L. Zhao, Y. P. Zhao, Y. X. Zhao, Z. G. Zhao, A. Zhemchugov, B. Zheng, B. M. Zheng, J. P. Zheng, W. J. Zheng, W. Q. Zheng, X. R. Zheng, Y. H. Zheng, B. Zhong, C. Zhong, X. Zhong, H. Zhou, J. Q. Zhou, S. Zhou, X. Zhou, X. K. Zhou, X. R. Zhou, X. Y. Zhou, Y. X. Zhou, Y. Z. Zhou, A. N. Zhu, J. Zhu, K. Zhu, K. J. Zhu, K. S. Zhu, L. X. Zhu, Lin Zhu, S. H. Zhu, T. J. Zhu, W. D. Zhu, W. J. Zhu, W. Z. Zhu, Y. C. Zhu, Z. A. Zhu, X. Y. Zhuang, M. Zhuge, J. H. Zou, J. Zu

High Energy Physics (Experiment)

Spin Physics at NICA SPD

Igor Denisenko

The Spin Physics Detector (SPD) is a universal detector at the NICA collider under commissioning at JINR, Dubna. The SPD is intended to study the spin structure of the proton and deuteron and other spin-related phenomena using a unique possibility to operate with polarized proton and deuteron beams at a collision energies up to 27~GeV and a luminosity up to 10$^{32}$cm$^{-2}$s$^{-1}$. As the primary goal, the experiment aims to provide access to the gluon TMD PDFs in the proton and deuteron, as well as the gluon transversity distribution and tensor PDFs in the deuteron, via the measurements of relevant single and double spin asymmetries using different complementary probes such as charmonia, open charm, and prompt photon production processes. Other polarized and unpolarized physics studies are possible, especially at the first stage of NICA operation with reduced luminosity and collision energy of the proton and ion beams. The physics program of the SPD and the design of the SPD setup will be presented.
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High Energy Physics (Experiment) · Cross-listed from nucl-ex

Three-baryon femtoscopy as an effective 3$\rightarrow$3 scattering experiment

ALICE Collaboration

Scattering experiments have long been the gold standard for constraining hadron$-$hadron interactions, providing direct information on the angular momentum and spin dependence over a wide range of kinematic configurations. However, experimental constraints on three-body dynamics remain limited, specifically for unbound systems and systems involving short-lived hadrons. In this work, the three-proton correlation function is measured in pp collisions at $\sqrt{s}=13.6$ TeV with ALICE at the LHC and presented as a novel approach to access hadronic interactions in three-body systems. A new analysis strategy is employed to isolate the p$-$p$-$p contribution to the correlation function by correcting for background channels and experimental effects, and enabling a direct comparison with state-of-the-art three-body continuum calculations. The extracted correlation function provides the first direct access to the isospin $3/2$ three-body system. The measured observable is found to be sensitive to the partial-wave structure of the nucleon$-$nucleon interaction and indicates that the nuclear interaction acts even at high angular momentum and parity states of the three-body system, revealing an effective long-range attractive component, observed experimentally for the first time in a three-proton continuum system. Hence, three-hadron femtoscopy emerges as an effective 3$\rightarrow$3 scattering experiment with three unbound hadrons in initial and final states. The copious production of hyperons at the modern high-energy colliders ensures the possibility of extending such measurements beyond nucleons, opening a new avenue for future precision studies of three-body dynamics in the strangeness sector.
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High Energy Physics (Experiment) · Cross-listed from physics.ins-det

Nonproportional Response of a GAGG Scintillator to Beta and Gamma Radiation over a Wide Energy Range in PIKACHU

Takumi Omori, Takashi Iida, Yosuke Suga et al. (+12 more)

Nonproportional response of scintillation light yield for sub-MeV radiations is a well-known characteristic of inorganic scintillators. In the PIKACHU experiment, a precise understanding of the nonproportional response of the GAGG ($\mathrm{Ce:Gd_3Al_2Ga_3O_{12}}$) scintillator is essential for background modeling. In this study, the nonproportional response of the GAGG scintillator was evaluated for both $\beta$ and $\gamma$ rays. The response for $\beta$ rays was measured using the Compton coincidence technique with a germanium detector, while that for $\gamma$ rays was evaluated using several monoenergetic $\gamma$-ray sources. The measurement results showed different responses for $\beta$ and $\gamma$ rays, with a stronger nonproportional response for $\gamma$ rays than for $\beta$ rays over the energy range of 50–2614~keV. The background model incorporating the measured nonproportional responses reproduced the measured background spectra more accurately compared with the model without the nonproportional response correction. These results demonstrate the importance of precise evaluation of the nonproportional response of the GAGG scintillator which is essential not only for background modeling in the PIKACHU experiment but also for accurate energy calibration in scintillator-based experiments.
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All authors Takumi Omori, Takashi Iida, Yosuke Suga, Masao Yoshino, Ken-Ichi Fushimi, Azusa Gando, Nobuo Hinohara, Keishi Hosokawa, Motonao Ishigami, Kei Kamada, Tadafumi Kishimoto, Keita Mizukoshi, Takuya Sako, Yasuhiro Shoji, Shota Sugi

Wednesday 5 August

High Energy Physics (Experiment) · Cross-listed from nucl-ex

ePIC Early Science Report

D. Abbott, N. Abdelrahman, S. Abhijit et al. (+796 more)

This Early Science Report from the ePIC Collaboration outlines the compelling physics program achievable during the first years of operation of the Electron-Ion Collider (EIC), prior to the establishment of the full design luminosity and energy range. The analyses are based on realistic early-running beam configurations and detailed Geant4 ePIC detector simulations, hit digitization and data reconstruction. The projected studies from the physics working groups of ePIC span inclusive, semi-inclusive, exclusive, diffractive and tagging, as well as jet and heavy flavor measurements in both electron-proton and electron-ion collisions. Even before the collider reaches its full design performance, these measurements will constrain parton distribution functions in nucleons and nuclei, access transverse-momentum-dependent and spin-dependent observables, probe gluon dynamics in nuclei, and initiate a program of imaging of quarks and gluons. Each measurement is directly connected to the core science pillars of the EIC, identified in the 2018 report by the National Academy of Sciences: understanding the origin of the nucleon mass, unraveling the spin structure of the nucleon, and exploring the emergent properties of dense gluonic matter. The results presented here provide examples that demonstrate that the early years of EIC running with ePIC will deliver novel world-leading insights into Quantum Chromodynamics. In addition, the early science program will establish measurement and analysis methodologies that will pave the way to the subsequent full EIC physics program.
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All authors D. Abbott, N. Abdelrahman, S. Abhijit, I. Abualrob, R. B. Achari, J. Adam, L. Adamczyk, K. Adkins, A. Affolder, K. Agarwal, J. Agarwala, N. Agrawal, C. A. Aidala, W. Akers, A. Al-bataineh, S. N. Alam, M. Alekseev, P. R. Altieri, J.-S. Alvarado Gallenao, S. B. L. Amar, R. Ammendola, I. Amos Cali, G. An, D. Anderson, E. Anderssen, V. Andrieux, G. Andronico, P. Antonioli, N. Apadula, D. Arkhipkin, W. Armstrong, M. Arratia, S. Arrigo, J. Arrington, M. Asai, A. Asaturyan, E.-C. Aschenauer, C. Ayerbe Gayoso, B. Azmoun, J. Bae, Y. Bae, X. Bai, V. Bailey, F. Barbosa, F. Barile, K. Barish, M. Bashkanov, S. Bathe, M. Battaglieri, A. Baty, A. Bazilevsky, T. D. Beattie, B. Beauchamp, Y. Bedfer, N. K. Behera, F. Bellini, R. Bellwied, H. Ben Hannan, M. Benettoni, M. Benoit, V. Berdnikov, J. Bernauer, H. Bervas, R. Besuner, J. Bettane, R. Bhadauriya, H. Bhatt, V. Bhopatkar, S. Bhosale, A. Biagioni, J. Bielcikova, J. Bielčík, Z. Biro, G. Boca, F. Bock, J. Bok, M. Bondi, A. Bonenfant, C. Bonini, M. Borri, F. Bossù, F. Bouyjou, O. Brand-Foissac, D. Brandenburg, N. Brei, A. Bressan, T. Britton, G. E. Bruno, M. Buckland, A. Buckley, L. Bucuru, E. Buron, A. Bylinkin, D. Cacace, H. Caines, A. Calivà, M. T. Camerlingo, P. Campero Rojas, A. Camsonne, M. Capua, F. Capuani, T. Carmarda, E. Casalotti, J. Ceska, I. Chakaberia, J. Chan, W.-C. Chang, M. Chartier, P. Chatagnon, C. Chatterjee, V. Chaumat, K.-F. Chen, Z. Chen, K.-Y. Cheng, Y. Cheng, S. Chevobbe, A. Cheyne, C. Chiarini, A. Chisari, S. Choi, P. Christoph, X. Chu, J. Chwastowski, A. Ciardiello, S. Ciarlantini, A. Cimini, E. Cisbani, Z. Citron, E. Cline, I. Cloët, D. Colella, M. Connors, M. Contalbrigo, G. Contin, S. Corey, R. Corliss, T. Cornet, F. Cossio, S. Costanza, J. Crafts, D. Cristancho, R. Cruz-Torres, A. D'Angelo, A. Dabat-Blondeau, E. Dahle, S. Dalla Torre, M. Daradkeh, S. Das, A. P. Dash, J. Datta, P. Datta, K. Davies, R. Dawson, A. De Caro, D. De Gruttola, S. De Pasquale, W. Deconinck, M. Defurne, Y. Degerli, C. Delafosse, A. Delbart, F. Delcarro, G. Dellacasa, M. Demarteau, Z. S. Demiroglu, G. W. Deptuch, A. Deshpande, D. Di Bari, B. Di Ruzza, R. Di Salvo, M. Diefenthaler, C. M. S. Divincenzo, X. Dong, B. Dongwi, V. Doomra, N. Doshita, A. Drees, R. Dupre, D. Dutta, R. Dzhygadlo, A. El Ouardi, L. El Fassi, D. Elia, B. Eng, R. Ent, Y. Eo, R. Esha, A. Eslinger, A. Evdokimov, O. Evdokimov, O. Eyser, V. Fadeyev, D. Falchieri, W. Fan, C. Fanelli, A. Fantini, F. Farrokhi, R. Fatemi, S. Fazio, S. Fegan, M. Finger, M. Finger, F. Flor, L. Flores, C. Flouzat, E. Fountain, B. Fraisse, A. Francisco, J. Frantz, S. Franzese, O. Frezza, N. Funicello, S. Furletov, Y. Furletova, C. Gal, H. Gao, M. Garbini, S. Gardner, P. Garg, D. Gaskell, V. Gaur, S. Geminiani, M. Gericke, F. Geurts, O. Gevin, T. Ghosh, P. Ghoshal, A. Gibson, I. Gildea, R. Gilman, D. Giordano, A. Giri, J. Giroux, P. Giubilato, D. I. Glazier, E. Glimos, J. Glover, K. Gnanvo, Y. Go, C. Goblin, L. Godfrey, L. Gonella, S. Gopinath, D. Gorni, M. Gouighri, S. Gramigna, K. Gray, S. V. Greene, M. Grosse Perdekamp, W. Gu, F. Guilloux, T. Gunji, J. Gupta, C. Gwenlan, T. Hachiya, E. Hagen, J. Haggerty, T. Hague, W. Ham, A. Hamed, R. Hamilton, X. Han, O. Hartbrich, M. C. Harvey, H. Hashamipour, S. Hassan, M. Hattawy, L. Havener, X. He, T. Hellstern, W. Helsby, T. Hemmick, O. Hen, S. Henry, D. Higinbotham, A. Hill, M. Hoballah, A. Hoghmrtsyan, M. Hohlmann, B. Hong, Y. Hong, T. Horn, D. Hornidge, I. Hossain, T. Hotta, C.-Y. Hsieh, Y. Hu, H. Z. Huang, J. Huang, J. Huang, S. Huang, G. Huber, A. Huddart, T. Huffman, P. Hurck, T. Hwang, C. Hyde, S. Iain, P. Iapozzuto, A. Illari, M. Inaba, G. M. Innocenti, A. Iqbal, D. G. Ireland, L. Isenhower, B. Jacak, N. Jacazio, M. Jadhav, S. Jain, H. Jang, S. Jang, O. Javakhishvili, J. Jaya, F. Jeanneau, A. Jentsch, Y. Jeong, T. Jeske, O. T. Jevons, S. Ji, J. Jia, H. Jiang, N. Jindal, H.-S. Jo, P. Jones, K. Joo, S. Joosten, A. Jung, O. Ka, G. Kainth, J. Kalani, N. Kalantarians, G. Kalicy, D. Kalinkin, M. Kaneta, K. Kauder, R. Kaundal, K. Kawade, S. Kay, M. Kebbiri, M. Kesler, A. Khanov, H. Khindri, A. Khuntia, Y. Khyzhniak, C. Kierans, A. Kim, B. Kim, B. Kim, C. Kim, E.-J. Kim, E. Kim, G. Kim, J. Kim, M. Kim, M. Kim, S. H. Kim, J. Kiryluk, A. Kiselev, J. Klay, S. Klein, H. Klest, V. Klimenko, N. Kobayashi, R. Koka, O. Korchak, I. Korover, L. Kosarzewski, A. Kostina, I. Krehbiel, A. Krieger, F. Krizek, T. Kumaoka, A. Kumar, K. Kumar, L. Kumar, R. Kumar, S. Kumar, M. Kumari, R. Kunnawalkam Elayavalli, C.-M. Kuo, T. Kutz, Y. Kwon, B.-Y. Ky, P. La Rocca, M. Labiche, R. Lacey, J. Lajoie, J. Lalic, K. Lalwani, E. Lancon, J. Landgraf, L. Lanza, R. Lassiter, D. Lattuada, J. Lauret, A. Laviron, O. Le Dortz, C. Le Gaillard, Y. Le Roux, C. Lee, H. Lee, H. Lee, J. Lee, J.-H. Lee, K. Lee, S. Lee, S. Lee, S.-J. Lee, Y.-J. Lee, S. Levorato, N. Lewis, S. Li, W. Li, W. Li, X. Li, B. Liang-Gilman, H. Lim, S. Lim, P.-J. Lin, W. Lin, M. Lisa, A. Liu, J. Liu, M. Liu, M. Liu, K. Livingston, T. Ljubicic, W. Llope, F. Lo Cicero, O. Lomický, A. Lonardo, E. Long, L. Long, R. Longo, S. Longo, R.-S. Lu, A. Lumanog, R. Ma, P. Maj, J. Mammei, F. Mammoliti, G. Mandaglio, S. Mandal, I. Mandjavidze, V. Manzari, S. Maple, D. Marchand, C. Markert, A. Martin, M. Martinelli, H. Marukyan, A. Mastroserio, G. Matousek, K. Matsutani, S. Mattiazzo, J. Maxwell, S. Mazza, B. McKinnon, A. S. Menon, J. Metcalfe, Z.-E. Meziani, A. Migayron, R. Milner, R. Milton, N. Minafra, C. Mingioni, Y. Miyachi, A. Mkrtchyan, H. Mkrtchyan, E. F. Molina Cardenas, M. K. A. Mondal, R. Montgomery, I. Mooney, B. Moreno, D. Morrison, S. Mouslih, A. Movsisyan, C. Munoz Camacho, S. Muraoka, M. Murray, T. Nagorna, C. J. Naim, A. Nambrath, S. Nanda, E. Nappi, V. Narendran, A. Natochii, V. S. Nattoja, C. Nattrass, H. Nayak, G. Nebin, D. Neff, M. Nenni, P. Newman, D. Neyret, M. Nguyen, N. Nicassio, S. Niccolai, G. Nigmatkulov, F. Noferini, P. Nord, J. Norman, R. Nothnagel, F. Noto, R. Nouicer, N. Novitzky, C. Nunez, J. Nystrand, S. Obratsov, L. Occhiuto, A. Ogawa, C. Oh, S. Oh, O. Olokunboyo, J. Osborn, M. Osipenko, S. Ota, J. Ott, G. Ottino, K. Oyama, E. O'Brien, B. S. Page, S. Pal, A. Paladino, P. Palni, A. Pandav, V. Pant, A. Panta, C. Pantouvakis, D. Panzieri, Z. Papandreou, S. Park, C. Pastore, V. K. Patel, S. Paul, S. Paul, C. Pecar, C. Peng, G. Penman, R. Perrino, P. Perticaroli, N. Pilleux, C. Pinkenburg, R. Pisani, S. Plavully, L. Polizzi, I. Ponce, L. Pontisso, M. Posik, M. Potekhin, E. Pottebaum, S. Prabhakar, R. Prabir, L. Preet, R. Preghenella, S. Priens, E. Prifti, M. Priyadarshini, I. Prochazka, T. Protzman, A. Prozorov, F. Prunes, M. Przybycien, P. Pujahari, P. Purohit, M. Purschke, B. Quni, S. Radhankrishnan, M. Radici, A. Rafaat, S. Rafael-Polcher, S. Rahman, R. Rajput-Ghoshal, A. Ramalingam, S. Rana, E. Rao, A. Rathi, F. Rathmann, A. Rathore, K. Read, P. Rebesan, R. Reed, B. Rehman, P. Reimer, G. Reis Garcia, J. S. Renck, S. Rescia, R. Ricci, J. Richards, C. Riedl, A. Riggio, L. Rignanese, M. Ripani, C. Ripoli, F. Rizatdinova, D. Rizk, J. Roche, G. Roland, D. Romanov, M. Rosati, C. Rossi, F. Rossi, E. Rovati, L. Ruan, N. Rubini, M. Ruspa, D. Ruth, J. Ryu, S.-Y. Ryu, F. Sabatié, R. Sadek, H. Sadrozinski, N. Saha, T. Sakaguchi, S. Salur, D. Samuel, P. Sanethavong, N. Santiesteban, A. Saputi, A. Sarkar, M. Sarsour, J. Schambach, B. Schmookler, B. Schumm, C. Schwarz, J. Schwiening, A. Seiden, R. Seidl, B. Seitz, H. Seong, L. Serin, Y. Shabaan, N. Shah, M. Shahid, P. Shanmuganathan, A. Sharma, D. Sharma, R. Sharma, A. Shatat, A. I. Sheikh, T.-A. Shibata, K. Shigaki, G. Shildt, T. Shin, S. Shiraskar, J. Shirk, J.-G. Shiu, N. Shouryasankar, E. Shulga, E. Sichtermann, E. Sidoretti, J. Silber, F. Simula, A. Singh, B. K. Singh, G. Singh, J. Singh, K. Slifer, N. Smirnov, A. Smith, J. Smith, K. Smith, D. Sokhan, G. Sommer, T. Song, R. Souvik, N. Speece-Moyer, F. Spizzo, M. Spreafico, N. St John, M. Stefaniak, P. Steinberg, J. Stevens, S. Stoll, E. Sun, K. Suresh, B. Surrow, M. C. Sutera, K. Sutowski, T. Sykora, H. Szumila-Vance, V. Tadevosyan, T. Takahshi, C. K. Tam, A. Tamis, U. Tamponi, X. Tan, D. Tapia Takaki, S. Tarafdar, E. Tassi, Y. Tayalati, L. Teodorescu, C. Terrevoli, F. Tessarotto, A. Teymurazyan, M. Thakur, D. Thomas, F. Thomson, A. Timmins, S. Titus, T. Toll, L. Tomasek, A.-S. Torrento, P. Tribedy, B. A. Trzeciak, O. Tsai, C. S. Tse, Z. Tu, R. Turrisi, C. Tuvé, B. Ujvári, T. Ullrich, G. M. Urciuoli, S. Vallarino, N. Valle, C. Van Hulse, M. Vandenbroucke, J. Vanek, Z. Varga, N. Vasim, J. Vasquez, S. Vasquez, J. Velkovska, G. Verde, S. Vetter, P. Vicini, G. Viehhauser, A. Vijay, A. Vijayakumar, D. Violette, T. Virgili, G. Volpe, A. Vossen, E. Voutier, F. Wang, G. Wang, P.-K. Wang, Y.-T. Wang, R. Wastie, J. Watkins, I. J. Watson, D. P. Watts, S. Welch, T. Wenaus, F. Wilson, R. Wimmer, S. Wissink, H. Witte, M. Wood, C. Woody, Y.-H. Xiao, J. Xie, W. Xie, Z. Xu, Z. Xu, Z. Xue, S. Yang, S. Yang, Y. Yang, S. Yano, Z. Ye, Z. Ye, Z. Ye, E. Yeats, K. Yip, K. Yongsun, H. Yoo, I. Yoon, D. Young, C. Yuen Tsang, N. Zachariou, W. Zha, S. Zhang, W. Zhang, Y. Zhang, Y. Zhang, Z. Zhang, Z. Zhang, Y. Zhao, Z. Zhao, V. Zhezer, B. Zihlmann, C. Zorn, M. Zurek, J. de Melo, D. de Souza Lemos, A. Accardi, I. Borsa, M. Cerutti, C. Cocuzza, J. Jiménez-López, K. Kumericki, R. Martinez, L. Rossi, P. Sznajder, A. Vladimirov, K. Wichmann, S. Yadav, P. Zurita

High Energy Physics (Experiment) · Cross-listed from hep-ph

Photon-nucleon entanglement in Compton scattering at low and high energies

Yoshitaka Hatta and Víctor Martínez-Fernández

We study spin-spin entanglement in the final state photon-nucleon system in Compton scattering, both at low energy below the pion threshold and at high energy in perturbative QCD to next-to-leading order. We first establish a no-go theorem showing that, for any spin-$\frac{1}{2}$ target, entanglement cannot be generated in unpolarized Compton scattering if the scattering amplitudes are real. We then consider polarized Compton scattering off the electron, the proton and the neutron. At low energy, we uncover a rich variety of maximally entangled Bell states and their unitary equivalents realized across different regions of the kinematic plane. Interestingly, the proton and neutron targets exhibit distinct patterns of entanglement. In the neutron case, the electric and magnetic polarizabilities dramatically influence the pattern and even the existence of entanglement. This suggests that entanglement can serve as a novel tool for investigating the detailed electromagnetic properties of the nucleons.
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High Energy Physics (Experiment)

Search for resonant production of lepton-enriched semivisible jets in proton-proton collisions at $\sqrt{s}$ = 13 TeV

CMS Collaboration

This search targets the resonant production of lepton-enriched semivisible jets (SVJs) from a strongly coupled dark sector, using 138 fb$^{-1}$ of proton-proton collision data collected with the CMS detector at the CERN LHC at $\sqrt{s}$ = 13 TeV. Two scenarios are investigated: jets enriched in all lepton flavors (SVJ$\ell$ signature) and jets predominantly enriched in tau leptons (SVJ$\tau$ signature). The analysis focuses on final states in which the missing transverse momentum is aligned with jets containing nonisolated leptons. A dual machine-learning strategy is employed, using a graph neural network for jet identification and a fully connected neural network that combines jet- and event-level information to enhance signal sensitivity and background estimation. The signal models assume a heavy Z' mediator with a benchmark coupling of 0.25 to standard model quarks, together with prompt decays of unstable dark hadrons. In the SVJ$\ell$ scenario, mediator masses up to 4.7 TeV are excluded at 95% confidence level, while masses between 1.8 and 3.5 TeV are excluded in the SVJ$\tau$ scenario. These results provide the first experimental constraints on lepton-enriched semivisible jets.
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High Energy Physics (Experiment) · Cross-listed from hep-ph

First-principles upper bounds on dark matter-electron scattering rates from condensed matter sum rules

Bradford A. Barker, Jay Epstein, Luke James et al. (+5 more)

A wide variety of condensed matter systems are used or proposed as detectors to search for dark matter-electron scattering. In general, the scattering rate depends on detailed knowledge of the electronic properties of these systems. However, when dark matter couples to electron density, the dark matter-electron scattering rate can be related to the electron energy loss function, whose integrals are bounded by first-principles sum rules that rely on only a few macroscopic target properties. In this paper, we use these first-principles sum rules to derive upper bounds on the dark matter-electron scattering rate depending on only a few material properties: the plasma frequency $\omega_\text{p}$, the target mass density $\rho_T$, and the static (longitudinal) dielectric function at finite momentum transfer, $\varepsilon(q, 0)$. The bulk material properties $\omega_\text{p}$ and $\rho_T$ vary only over a limited range across a wide variety of materials, and to a good approximation, the generic large-$q$ dependence of $\varepsilon(q, 0)$ can be understood from a simple scaling law depending only on $\omega_\text{p}$ which we verify with analytic and numerical examples. Thus, our upper bounds are largely material-agnostic, and place a fundamental limit on the sensitivity of any dark matter-electron direct detection experiment probing the coupling to electron density.
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All authors Bradford A. Barker, Jay Epstein, Luke James, Yonatan Kahn, Elizabeth A. Peterson, Anirudh Prabhu, Tanner Trickle, Samuel L. Watkins

High Energy Physics (Experiment) · Cross-listed from hep-ph

The QCD Axion and Neutrino Masses

Hridoy Debnath, Pavel Fileviez Perez and Grace Miller

The strong CP problem and the origin of neutrino masses are among the clearest motivations for physics beyond the Standard Model. The Peccei-Quinn mechanism offers an elegant dynamical solution to the strong CP problem, predicting the QCD axion, while neutrino masses point to new degrees of freedom or interactions beyond the Standard Model. We explore the possibility that these two phenomena arise from a common origin by identifying the Peccei-Quinn symmetry-breaking scale with the scale responsible for neutrino mass generation. We perform a systematic and unified analysis of this connection in both DFSZ and KSVZ realizations of the Peccei-Quinn mechanism, considering the Type-I, Type-II, and Type-III seesaw mechanisms, the Zee radiative model, and the colored seesaw. For each scenario, we determine the axion couplings to photons and neutrinos and examine their phenomenological consequences. A robust prediction of all the frameworks considered is the existence of axion-neutrino couplings. We show that these interactions can significantly affect the axion decays. If the QCD axion makes up the observed dark matter, these couplings also lead to a large monochromatic neutrino flux from axion decays, opening a complementary path to test these theories in future neutrino experiments.
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High Energy Physics (Experiment) · Cross-listed from hep-ph

High energy probes of Higgs self-coupling via $W$ boson fusion at future lepton colliders

Amir Subba, Hrishikesh Deka, Subhaditya Bhattacharya et al. (+1 more)

We investigate the sensitivity to the Higgs self-coupling through $W$ boson fusion di-Higgs production at CLIC with a center-of-mass energy of $\sqrt{s}=3$ TeV. We study the interplay between the Higgs self-coupling modifier ($\kappa_{\lambda}$) and Higgs-gauge coupling modifiers ($\kappa_{V}$ and $\kappa_{2V}$) within the $\kappa$ framework. To enhance the separation between signal and background, we develop a graph neural network (GNN) based classifier that achieves a signal significance of $\mathscr{Z}\approx 20~\sigma$ at $5~\mathrm{ab}^{-1}$, substantially exceeding projected HL-LHC sensitivity. Our results demonstrate that high-energy lepton colliders, combined with graph-based machine learning, provide excellent sensitivity to the Higgs self-coupling and offer a powerful probe of new physics in the electroweak sector, disentangling linearly and non-linearly realized electroweak symmetry breaking.
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All authors Amir Subba, Hrishikesh Deka, Subhaditya Bhattacharya, Abhik Sarkar