High Energy Physics (Phenomenology)
A global analysis of ${\bar B}\to DP$ and ${\bar B} \to {\bar D} P$ decays
Bhubanjyoti Bhattacharya, Rida Boumris and David London
Recently, a fit to the 15 measured branching ratios of ${\bar B} \to D P$ decays ($B = \{B^+, B^0, B_s^0\}$, $D = \{D^0, D^+, D_s^+\}$, $P \in \{\pi, K\}$) was performed under the assumption of flavor SU(3)
symmetry [SU(3)$_F$]. A terrible fit was found: there was a $> 5\sigma$ disagreement with the SU(3)$_F$ limit of the Standard Model [SM$_{\rm{SU(3)}_F}$]. It was also found that this discrepancy can be removed by adding $\sim 20\%$ SU(3)$_F$-breaking effects. Now, the ${\bar B} \to D^0 P$ amplitudes can contribute to other observables (direct and indirect CP asymmetries) if they interfere with the amplitudes for ${\bar B} \to {\bar D}^0 P$ decays. This happens if the $D^0$ and ${\bar D}^0$ decay to the same final state (e.g., $K^+ K^-$, $\pi^+ \pi^-$, $K^\pm \pi^\mp$, etc.). In this paper, we perform a combined fit of ${\bar B} \to D P$ and ${\bar B} \to {\bar D} P$ decays, including all observables. We again find a $> 5\sigma$ disagreement with the SM$_{\rm{SU(3)}_F}$, and we find that the data can be explained if $\sim 60\%$ SU(3)$_F$-breaking effects are included.
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High Energy Physics (Phenomenology)
Transient PULSE: Code for the Transient Propagation of UltraLight (pseudo)Scalars to Earth
Jason Arakawa, Charles Cheung, Muhammad Hani Zaheer et al. (+2 more)
We present Transient PULSE, a software package that numerically implements a previously developed source-to-detector framework for transient ultralight bosonic signals from astrophysical bursts. Predicting these signals relies on connecting the source emission spectrum to its
evolution during propagation and the resulting observables at a terrestrial detector. The package discretizes a user supplied energy spectrum into momentum modes, propagates them through a specified matter density profile and constructs the time-frequency energy density distribution at Earth, accounting for dispersion and in-medium screening effects. This treatment accommodates non-Gaussian source spectra and provides inputs for detector specific analyses. A complementary analytical module estimates coupling sensitivities, arrival time delays and screening thresholds from parameterized source and detector properties.
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All authors Jason Arakawa, Charles Cheung, Muhammad Hani Zaheer, Volodymyr Takhistov, Marianna Safronova
High Energy Physics (Phenomenology)
Top-Quark Mass Scheme Uncertainties in Higgs Boson Pair Production via Gluon Fusion
Clara Del Pio, Sebastian Jaśkiewicz, Rebecca von Kuk et al. (+1 more)
We investigate theoretical uncertainties arising from the choice of the top-
quark mass scheme in
Higgs boson pair production via gluon fusion. First, we implement the resummation of the top-
quark mass logarithms obtained for the $gg\to HH$ amplitude at high energy and study its phenomenological impact on cross sections. Second, we formulate a threshold-aware treatment of the top-
quark mass based on short-distance mass definitions, combining an MSR description near the top-pair threshold with an $\overline{\mathrm{MS}}$ treatment in the high-energy regime. Within the dynamical prescription, the combined mass-scheme variation of the SM inclusive NLO cross section at $\sqrt{s}=14$ TeV is $^{+5.2\%}_{-0.2\%}$. This estimate provides an alternative to the conventional OS-$\overline{\mathrm{MS}}$ envelope.
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All authors Clara Del Pio, Sebastian Jaśkiewicz, Rebecca von Kuk, Robert Szafron
High Energy Physics (Phenomenology)
Effects of quadratic frequency chirping and carrier-envelope phase on Schwinger pair production in polarized electric fields
Abhinav Jangir
We investigate electron-positron pair production in spatially homogeneous, time-dependent polarized electric fields using the Dirac-Heisenberg-Wigner formalism, focusing on the effects of symmetric and asymmetric quadratic frequency chirping and the carrier-envelope phase (CEP). Our analysis reveals how these field parameters govern both the momentum-space structure and the overall yield of the produced pairs. Frequency chirping substantially reshapes the momentum distributions by modifying their interference patterns and peak occupations. The momentum distributions are particularly sensitive to weak chirping, whereas strong chirping produces pronounced oscillatory and ring-like structures across all polarization states. The total pair yield increases with chirp strength, with symmetric chirping consistently producing a higher yield than asymmetric chirping for the parameter range considered. Moreover, the sensitivity of the total number density to polarization decreases progressively with increasing chirp strength, becoming negligible in the strongly chirped regime. The CEP further modifies the momentum distributions by altering their shapes and relative peak occupations, with the extent of these changes depending on the polarization state. Our findings establish a theoretical framework for exploring external-field configurations that optimize the yield of Schwinger pair production.
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High Energy Physics (Phenomenology) · Cross-listed from astro-ph.HE
Can bosenovae deplete the galactic dark matter?
Samuel Gómez Gómez and Joshua Eby
No: neither through the bosenovae of gravitational atoms formed around
stars and compact objects, nor through those of
boson stars formed in the galactic dark-matter
halo. We assume that all the dark matter consists of ultralight
bosons with attractive self-interactions, which can be captured in the gravitational potential of astrophysical objects or condense into self-gravitating configurations. When these systems collapse in a bosenova, part of their mass is turned into relativistic radiation that escapes the
galaxy. We bound the mass that a single object can eject and sum it over realistic models of the Milky Way and of other types of
galaxies. For gravitational atoms, with realistic stellar populations and stellar
evolution, the
stars of the Milky Way deplete at most $\epsilon^{\rm GA}_\star\simeq3\times10^{-9}$ of its
halo, and the pump is equally negligible in other
galaxies. The central black hole, Sgr A$^*$, could reach $\epsilon^{\rm GA}\sim10^{-3}$, but only for a
boson mass disfavoured by ultrafaint dwarf
galaxies and beyond the validity of the perturbative treatment, where only a
geometric bound on the dark matter flux is available. For
boson stars feeding on the rest of the
halo, these would radiate at most $\sim3\times10^{-5}$ of the Milky-Way
halo and $0.1\%$ of a DF2-like one.
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High Energy Physics (Phenomenology)
Brownian GPDs: A Stochastic Calculus Approach to Generalized Parton Distributions from Integral Constraints
Douglas Q. Adams, Simonetta Liuti, Zaki Panjsheeri et al. (+1 more)
We present a
stochastic calculus approach for modeling generalized parton distribution functions using information provided from
lattice QCD calculations of Mellin moments, without assuming a functional form. Reconstructing the underlying dependence on the partonic momentum fraction from a limited number of moments constitutes an intrinsically non-unique inverse problem. Our goal is to provide a model agnostic way to determine GPDs subject to integral constraints. Thus, we derive and show usage of a controlled Langevin approach based on
stochastic calculus and Brownian motion. The method combines a variational formulation, based on minimizing a Dirichlet action subject to the imposed constraints, with
stochastic dynamics that generates an ensemble of admissible functions. The resulting ensemble provides a preferred reconstruction and characterizes the variability associated with incomplete integral information within the chosen
stochastic model. The framework can accommodate general integral kernels and prescribed function values, offering a flexible approach to reconstructing functions from indirect constraints. Beyond its application to GPD phenomenology, the method provides a general strategy for investigating inverse problems in which integral observables are known but the underlying functional dependence remains undetermined. The approach may have more general applications beyond the scope of studying 3D
hadron structure, and it is particularly useful in situations where we know definite integrals of functions with kernels, but do not know the underlying function.
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All authors Douglas Q. Adams, Simonetta Liuti, Zaki Panjsheeri, Brannon Semp
High Energy Physics (Phenomenology)
Strangeness suppression, the $\phi$ meson and $\Lambda\bar\Lambda$ spin correlations from exact strangeness conservation at the quark level
P. Castorina and H. Satz
In small collision systems strange
hadrons are suppressed, and the suppression grows with the number of strange
quarks. Exact strangeness conservation in a finite volume accounts for this, but when it is imposed on
hadrons it leaves the $\phi$
meson unsuppressed, contrary to observation. We impose the conservation law on the strange
quarks in a causally connected cluster, before hadronization, and count separately the combinations of a strange
quark with the antiquark created together with it. A pair created from the
vacuum cannot form a $\phi$, a pair created from a gluon can only if it loses its color. With one function of multiplicity, the mean number of strange
quarks per cluster, the model describes kaons, $\phi$, $\Xi$ and $\Omega$ in pp and p–Pb collisions at the LHC; the data require that about half of the same-pair combinations are excluded from the $\phi$, and reject both an unsuppressed $\phi$ and a $\phi$ built only from different pairs at about five standard deviations. The same-pair combinations are those that carry the
spin correlation observed in $\Lambda\bar\Lambda$ production, whose dilution is thereby tied to the $\phi$ suppression and is predicted to decrease with multiplicity
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High Energy Physics (Phenomenology)
Evolution of multihadron fragmentation functions with nonperturbative behavior
K. Makino and T. C. Rogers
QCD calculations that use multihadron fragmentation functions usually involve multiple invariant mass scales simultaneously, with only one being the hard scale associated with an overall hard process. The other scales are associated with relative internal motion intrinsic to the fragmenting parton and the multihadron system. Nonperturbative contributions to this later type of dependence attract interest for their association with intrinsic partonic structures, but care is needed in disentangling the truly nonperturbative effects from perturbative behavior and relating the former to universal nonperturbative
matrix elements. To this end, we show how to evolve collinear multihadron fragmentation functions in a way that accounts for the simultaneous presence of these extra scales. The general multihadron fragmentation functions evolve in the same way as ordinary single
hadron fragmentation functions, with the dependence on the extra scales separated out. We use this to unify treatments of perturbative and nonperturbative effects in multihadron systems in a way that optimizes for interpretations focused on partonic structure.
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High Energy Physics (Phenomenology)
Displaced tracks as a signal of dark matter co-annihilation: a case study using inert doublet model at $e^+e^-$ collider
Hrishikesh Deka, Subhaditya Bhattacharya, Amir Subba et al. (+1 more)
Dark sector containing heavy (charged) particles with small mass splitting with dark matter (DM) can co-annihilate and produce correct relic density, evading direct detection bounds. In such compressed spectra, the charged state can be long-lived and decay to DM along with a very soft charged particle, giving rise to distinctive disappearing or kink track signatures at
colliders. As an example, we consider the Inert Doublet Model (IDM), where the charged scalar $H^\pm$ can be nearly degenerate with the neutral DM state ($H^0$), and produce a soft pion ($\pi^\pm$) when it decays. We investigate this signature at a future $e^+e^-$
collider, focusing on electroweak $H^+H^-$ pair production and its displaced decays. By varying the mass splitting, we explore the transition from
prompt soft-particle signatures to long-lived and disappearing-track signatures. Our analysis demonstrates the potential of future lepton
colliders to probe the interplay between the charged-particle lifetime, its decay probability within the tracking volume, and the production rate sensitivity to the compressed DM scenarios over a broad range of masses, allowed by cosmological constraints.
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All authors Hrishikesh Deka, Subhaditya Bhattacharya, Amir Subba, Ritesh K. Singh
High Energy Physics (Phenomenology) · Cross-listed from hep-lat
Excited-State Effects in Nucleon Sigma Terms from a Variational Analysis
Constantia Alexandrou, Giannis Koutsou, Yan Li et al. (+2 more)
We investigate excited-state effects in nucleon sigma-terms in
lattice QCD using twisted-mass clover-improved
fermion ensembles. We study correlation functions with nucleon and multihadron nucleon-$\sigma$-
meson interpolating operators. The analysis is performed using three gauge ensembles, including one ensemble simulated with two degenerate light, a strange, and a charm
quark with
quark masses tuned to approximately their physical value. We solve the generalized
eigenvalue problem that arises from the
matrix of correlators and show that the three-point function for the light sigma-term obtained using the optimal linear combination of interpolating operators has substantially reduced time dependence without loss of statistical precision. We apply Laplace filtering and investigate residual excited-state contributions in the extraction of $\sigma_{\pi N}$. Using the same optimal linear combination of correlators as for $\sigma_{\pi N}$ for the strange sigma-term we also observe suppressed excited state contributions over an extended range of source–sink time separations. For the charm sigma-term, we observe negligible time dependence within the large statistical uncertainties, and these improvements show no significant effect.
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All authors Constantia Alexandrou, Giannis Koutsou, Yan Li, Srijit Paul, Ferenc Pittler
High Energy Physics (Phenomenology)
Thermal properties of the $\rho$ meson from a machine-learning-improved holographic QCD model
Jia-Jie Jiang, Han Tang, Danning Li et al. (+1 more)
The thermal properties of the \(\rho\)
meson are revisited within the soft-wall AdS/QCD framework. The dilaton background is calibrated against
lattice QCD screening-mass data through a neural-network-assisted inverse procedure. Using this calibrated background, we compute the temporal vector spectral function and the lowest vector quasi-normal modes. The pole mass \(m_{\mathrm{pole}}(T)\) and thermal width \(\Gamma(T)\) are then extracted from the corresponding complex quasi-normal mode frequencies. Adopting the vanishing real part of the quasi-normal mode frequency, \(\omega_{\mathrm{Re}}(T_d)=0\), as a criterion for
meson dissociation, we estimate \(T_d\approx168\,\mathrm{MeV}\). As the temperature increases, the thermal width grows, and the spectral function evolves from a narrow Breit-Wigner-like resonance peak into a transport peak, confirming the QNM prediction that the vanishing of the pole mass is accompanied by the emergence of a transport peak and making it difficult to identify a quasiparticle peak. A numerical extraction of the dispersion relation shows that the propagator can be described by a finite-temperature simple-pole form with momentum-dependent thermal width, characterized by a
diffusion coefficient \(D(T)\) and an effective propagation speed \(u(T)\), whose temperature dependences are also extracted. This form modifies the usual relation between the screening and pole masses. These results may provide a useful reference for effective studies of the hot hadronic medium.
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All authors Jia-Jie Jiang, Han Tang, Danning Li, Lang Yu
High Energy Physics (Phenomenology)
Transport of hard probes in the glasma
Dana Avramescu
The
quark-gluon
plasma (QGP) formed in relativistic heavy-ion collisions at RHIC and the LHC thermalizes from an out-of-
equilibrium state of strong classical gluon fields known as the glasma. Jets and heavy
quarks, produced in the initial scatterings, traverse these pre-
equilibrium fields, but the glasma stage is neglected in phenomenology, which may bias the extracted QGP transport coefficients. This thesis studies its impact on jet and heavy
quark transport. The glasma is described in the Color Glass Condensate framework by solving the classical Yang-Mills equations on a real-time
lattice. The fields initially form longitudinal electric and
magnetic flux tubes whose transverse correlation length is set by the saturation scale $Q_s$. Probes are studied with both classical transport equations and
quantum evolution in the light-front
Hamiltonian approach. The transport coefficients for jets and heavy
quarks are much larger than in the QGP and anisotropic between transverse and longitudinal directions. The azimuthal decorrelation of back-to-back $c\bar{c}$ pairs in the glasma is comparable to that from the QGP, making $D\bar{D}$ angular correlations a potentially measurable glasma signature. The glasma also modifies the nuclear modification factor $R_{AA}$, though the effect is moderate compared to the nuclear parton distribution contribution. A systematic gauge-invariance analysis shows that the distinction between kinetic and canonical momenta is essential when comparing classical and
quantum results, and that Coulomb gauge fixing largely reduces gauge artifacts. Finally, the eikonal
quantum evolution of a high-energy
quark is studied with time-dependent Basis Light-Front Quantization. The resulting momentum broadening agrees with the classical estimates and lays the groundwork for including
quantum radiation.
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High Energy Physics (Phenomenology)
Spin and 3D structure: theoretical advances
Markus Diehl
Theoretical studies of
hadron structure have made important progress since the previous DIS workshop in 2025. This talk reviews selected new results and developments, with a focus on
spin dependent parton distributions, on transverse-momentum distributions and their rapidity dependence, on generalised parton distributions, and on the evaluation of power corrections.
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High Energy Physics (Phenomenology)
Correlation between gravitational wave frequencies as a signature of new black hole physics
Ngo Phuc Duc Loc
We point out that for black holes (BH) of the same mass, despite of arising from two entirely different physical arguments, the peak frequency of the coarse-grained gravitational wave (GW) spectrum of gravitons $f_\text{peak}^\text{graviton}$ is very close to the peak frequency of the GW spectrum produced from binary BH mergers $f_\text{peak}^\text{merger}$. In particular, we find that $f_\text{peak}^\text{graviton}/f_\text{peak}^\text{merger}\approx 2.3$ independent from BH mass or population. If BHs are still evaporating, the peak frequencies scale as $\propto M_i^{-1}$ with $M_i$ is the initial BH mass. If BHs evaporated in the radiation (matter) dominated era, the peak frequencies scale as $\propto M_i^{1/2}$ ($\propto M_i$) respectively after taking into account
redshift effect. Any deviation from the aforementioned magical ratio would indicate new BH physics. The sweetest frequency ballpark to look for this correlation is around $10^{14}\ \rm Hz-10^{20}\ \rm Hz$ where both GW spectra are allowed to have maximum amplitude. As a demonstration of what the new physics could be, we consider a phenomenological self-similar regular BH model of Hayward featuring a single hair parameter. The observed ratio of peak frequencies can be used to directly infer the hair parameter, along with crucial properties of the novel BH solution such as Hawking temperature, horizon size, and innermost stable circular orbit. We also comment on the pros and cons of correlating frequencies among other GW sources such as formation, population fluctuation, and sudden transition of adiabatic perturbation.
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High Energy Physics (Phenomenology)
The dead-cone effect in charm, bottom and top quark jets in angular and momentum space
Redamy Perez-Ramos, Stefan Kluth and Wolfgang Ochs
The dead-cone effect reflects the mass dependence of QCD radiation from heavy
quarks. We investigate this phenomenon from charm and bottom to top
quarks using two-dimensional angular distributions and single-particle inclusive momentum spectra. The angular distributions illustrate the depletion of radiation around the heavy-
quark direction, while the momentum spectra provide a quantitative observable of the effect. For charm and bottom jets, fragmentation functions reconstructed from LEP data at the $Z$ pole exhibit a strong suppression of high-momentum particles, quantitatively described within the Modified Leading Logarithmic Approximation of perturbative QCD. The analysis is extended to $\sqrt{s}=1$ TeV using Monte Carlo simulations. A hypothetical stable-top sample isolates the primary top-
quark radiation pattern, whereas the physical decay $t\to bW$ introduces coherent radiation from the $tb$ colour dipole, obscuring the primary dead cone. By exploiting the dependence on the $b$-
quark emission angle $\Theta_b$, we reconstruct the primary top-
quark parton momentum spectrum through extrapolation to $\Theta_b\to0$. In contrast, the small-angle gluon and parton distributions do not converge to the stable-top dead-cone pattern because of radiation from the decay $b$
quark. These findings establish the inclusive momentum spectrum as a robust quantitative observable of the top-
quark dead-cone effect and provide a unified description of mass-dependent QCD radiation from charm to top.
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High Energy Physics (Phenomenology) · Cross-listed from hep-th
The stability of non-Abelian $A_4$ vortices in $SO(3)$ gauge theory
Yoshihiko Abe, Tetsutaro Higaki, Kazuya Murakami et al. (+2 more)
We study the linear energetic stability of non-Abelian
vortices in an $SO(3)$ gauge-
Higgs theory with residual gauge group $A_4$. In our previous work, we identified two families of such
vortices associated with order-two and order-three elements of $A_4$, and found Bogomol'nyi–Prasad–Sommerfield-like behavior at special ratios of the
Higgs and gauge-
boson mass scales. Here, we investigate their stability against $SO(3)$ gauge and
Higgs perturbations by analyzing the second order variation of the
vortex tension using analytical and numerical methods. In particular, when all relevant mass scales are equal, we prove linear stability for all
vortices in the order-three family. By contrast, at the same mass point, we prove that a
vortex in the order-two family is unstable. Thus, although both
vortex families exhibit Bogomol'nyi–Prasad–Sommerfield-like behavior in their reduced equations at this mass point, their stability properties in the full $SO(3)$ theory are qualitatively different.
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All authors Yoshihiko Abe, Tetsutaro Higaki, Kazuya Murakami, Muneto Nitta, Ryo Yokokura
High Energy Physics (Phenomenology) · Cross-listed from hep-ex
MoEDAL-MAPP: the first dedicated search experiment at the LHC
John R. Ellis, Nick E. Mavromatos, Vasiliki A. Mitsou et al. (+1 more)
This special issue brings together a collection of original research articles and review papers addressing topics directly related to the MoEDAL-MAPP experiment at the Large
Hadron Collider (LHC). The experiment is designed to search for (meta-)stable, anomalously ionising particles predicted by theoretical extensions of the Standard Model. Several contributions explore the theoretical and phenomenological aspects of models of particular relevance to the experiment, including scenarios involving
magnetic monopoles, highly electrically charged particles, and millicharged particles. Other contributions focus on experimental developments, highlighting novel detection techniques and technological advances aimed at identifying these unconventional signatures and probing new phenomena beyond the Standard Model.
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All authors John R. Ellis, Nick E. Mavromatos, Vasiliki A. Mitsou, James L. Pinfold
High Energy Physics (Phenomenology)
The Semileptonic B Frontier: LHC, B-factories, Lattice QCD & the Hunt for Precision
F. De Fazio, P. De Simone, M. Fedele et al. (+33 more)
This review document summarizes the main outcomes and key theoretical and experimental developments discussed at the workshop “The Semileptonic $B$ Frontier: LHC, $B$-Factories,
Lattice QCD & the Hunt for Precision”, held at Laboratori Nazionali di Frascati on 16–18 February, https://agenda.infn.it/event/49469/. Bringing together experimentalists and theorists, the meeting addressed recent advances and outstanding challenges in both charged-current ($b \to c/u\,\ell\nu$) and neutral-current ($b \to s\,\ell^+\ell^-$) semileptonic $b$-
hadron decays. We synthesize current experimental measurements from Belle, Belle~II, and LHCb with state-of-the-art theoretical inputs—including
Lattice QCD determinations, Heavy
Quark Expansion (HQE) frameworks, and QED radiative corrections. In addition to reviewing the status of CKM
matrix elements, hadronic form factor extractions, and Lepton Flavor Universality (LFU) tests, this report highlights novel observables and fitting techniques designed to maximize the sensitivity of future analyses and guide upcoming data-taking campaigns.
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All authors F. De Fazio, P. De Simone, M. Fedele, G. Finocchiaro, F. Mescia, M. Rotondo, A. Barone, B. Capdevila, M. De Cian, L. Dreyfus, M. Fael, G. Finauri, G. Gagliardi, G. Gaudino, D. Giusti, N. Gubernari, A-M. Heyn, F. Manganella, E. Minucci, B. Mitreska, E. Manoni, T. Martinov, L. Paolucci, Z. Polonsky, A. Poluektov, M. Palutan, F. Sanfilippo, S. Simula, A. Smecca, N. Tantalo, A. Tinari, A. Vaquero, R. Vazquez Gomez, M. Valli, L. Vittorio, V. Vobbilisetti
High Energy Physics (Phenomenology)
Quantum-enhanced Search for Galactic Dark Photons Using Cat-State Cavities
Aoying Wang, Yanjie Zeng, Yanyan Cai et al. (+4 more)
We present a
quantum-enhanced search for the Galactic dark-
photon background (GDPB), a relativistic and anisotropic vector field that can be produced by dark-matter decay or annihilation in the Milky Way
halo. We reinterpret an existing
quantum-enhanced dark-
photon dataset obtained with a superconducting
circuit QED platform originally developed for wave-like dark-
photon dark-matter searches, consisting of a high-$Q$ niobium cavity in the $\mathrm{TM}_{010}$ mode dispersively coupled to a transmon
qubit. By preparing four-component cat states and performing repeated
quantum non-demolition parity measurements, analyzed with a hidden Markov model, we extract
photon-transition probabilities for multiple cat amplitudes and integration times. The coupling to the GDPB is governed by a polarization- and angle-dependent cavity overlap function, which predicts a distinctive diurnal modulation of the excitation rate for both longitudinal and transverse polarizations. From the absence of such modulation, we set 90% confidence-level bounds on the kinetic-mixing parameter $\epsilon$ for two
benchmark production mechanisms (parametric and cascade decay) over the relativistic mass range $m_X \ll \omega_c$.
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All authors Aoying Wang, Yanjie Zeng, Yanyan Cai, Jing Shu, Bin Xu, Yuan Xu, Pan Zheng
High Energy Physics (Phenomenology)
Decoherence as a Detector-Resolution Flow
Yao Ji and Yuqi Wang
We consider the QED final-state radiation modeled by $\gamma\gamma^\ast\to\pi^+\pi^-+X$, including its finite-temperature generalization, as an open
quantum system, and study the
evolution of the pion-pair momentum density
matrix as the detector resolution scale is varied. We derive an explicit relation between the Lindblad jump operator and the Wilson line associated with soft
photon radiation. We find that real emission and virtual correction serve as two separate contributions to momentum decoherence, and together they give rise to the real–virtual cancellation at the density-
matrix level. The external finite-temperature
photon bath modifies the decoherence rate by a Bose factor consistent with the Feynman–Vernon influence-functional approach. We emphasize that our conclusions also apply to hard
fermion production thanks to the universality of the soft radiation.
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High Energy Physics (Phenomenology) · Cross-listed from astro-ph.HE
Constraint on particle mass of dark matter based on XTE J1814-338 observation and DANS model
Lin Wang and Dehua Wen
The small observed radius of
neutron star XTE J1814-338 (with mass of $1.21_{-0.05}^{+0.05}$ $M_{\odot}$ and radius of $7_{-0.4}^{+0.4}$ $\rm{km}$) poses a great challenge to the traditional
neutron star model composed of normal nuclear matter. The dark matter admixed
neutron star (DANS) model provides a clue to solve this challenge. By employing the self-interacting fermionic dark matter model, we investigate the effects of dark matter parameters including the particle mass, self-interaction strength, and mass fraction of dark matter on the properties of DANSs. Our results indicate that the joint constraints from the observation of XTE J1814-338 and the astrophysical limits on the dark matter self-interaction cross section derived from observations of different colliding
galaxy clusters can provide effective constraints on the particle mass of dark matter. Specifically, to simultaneously satisfy the small radius of XTE J1814-338 and the self-interaction limit, the particle mass of self-interacting fermionic dark matter is constrained to the range from sub-GeV to a few GeV.
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High Energy Physics (Phenomenology) · Cross-listed from astro-ph.HE
Correlation of galactic very-high-energy gamma-ray sources detected by LHAASO with high-energy neutrinos
Long-Yu Zhang and Kai Wang
We conducted an investigation into the possible correlation between very-high-energy (VHE, $E>$ 0.1 TeV) gamma-ray sources, as identified by the Large High Altitude Air Shower Observatory (LHAASO), and high-energy
neutrino events captured by the IceCube
Neutrino Observatory. For this analysis, we utilized the First LHAASO catalog, which comprises 90 VHE gamma-ray sources, and the IceCube Event Catalog of Alert Tracks (IceCat-1), which includes 348 track-like
neutrino events. Through Monte Carlo simulations, we assessed the correlations between the
neutrino events and LHAASO sources, achieving the best p-values of 0.237, 0.312, and 0.115, respectively, for all LHAASO sources, KM2A sources, and WCDA sources. These findings imply that the spatial coincidence between LHAASO sources and
neutrino alerts is relatively weak. Furthermore, under the assumption that gamma-rays are exclusively generated through hadronic interactions, we estimated the most optimistic theoretical
neutrino fluxes from LHAASO sources and compared them with the IceCube observed fluxes. The results indicate that the majority of these sources are improbable counterparts to the detected
neutrinos. In conclusion, LHAASO sources could be potential galactic
neutrino emitters but currently do not exhibit compelling evidence, thereby underscoring the necessity for elevated sensitivity levels in forthcoming detection instruments like IceCube-Gen2.
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High Energy Physics (Phenomenology)
Radion/Dilaton portal freeze-in dark matter in extra-dimensional theories
Amrita Mukherjee, George Sanamyan and Dipan Sengupta
We perform a comprehensive analysis of a radion/dilaton portal freeze-in dark matter in models of stabilized warped extra-dimensions. We show that the relic abundance of a generic dark matter particle (scalars, vectors, or
fermions) is obtained via the conformal coupling of the radial mode in a consistent model stabilized warped extra- dimensions; our calculations show that in scenarios where the reheating temperature is much smaller than the radion mass, keV-TeV scale dark matter particles can saturate the relic density. We perform a comprehensive analysis of a radion/dilaton portal freeze-in dark matter in models of stabilized warped extra-dimensions. We show that the relic abundance of a generic dark matter particle (scalars, vectors, or
fermions) is obtained via the conformal coupling of the radial mode in a consistent model stabilized warped extra- dimensions; our calculations show that in scenarios where the reheating temperature is much smaller than the radion mass, keV-TeV scale dark matter particles can saturate the relic density. Furthermore, we show that the model is subject to Lyman-alpha constraints in the keV-GeV range, providing a unique, model-independent probe of this sector. Our calculations extend previous attempts to calculate the freeze-in relic abundance in extra-dimensional portals by providing a consistent theoretical calculation of
matrix elements, clearly laying out the underlying motivation and assumptions and providing a comprehensive account of the cosmological constraints on the model.
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High Energy Physics (Phenomenology)
Superhorizon enhancement of the hydrodynamic GW tail in Standard Model embedded warm inflation
Simone Biondini and M. Laine
Hydrodynamic fluctuations in the primordial
plasma generate a gravitational-wave (GW) background that grows like $f^3_\mathrm{\scriptscriptstyle 0}$ in terms of the current frequency. However, within the ($10^{-4}_{ } ... 10^4_{ })\,$Hz band of upcoming interferometers, the modes likely re-entered the Hubble horizon when the hydrodynamic noise was no longer at its maximal value. To address this situation, we define a model-independent transfer function for GWs generated by hydrodynamic (or other white-noise) fluctuations at any time. Employing appropriate variables, we show how this transfer function, together with the simpler
vacuum one, can be determined numerically for a general expansion history. The results are illustrated for Standard Model embedded warm inflation scenarios, including both the
vacuum and hydrodynamic parts. Following previous estimates, we find that a pre-exit-generated hydrodynamic tail becomes almost flat below $(10^5_{ } ... 10^7_{ })\;$Hz. Its small-$f^{ }_\mathrm{\scriptscriptstyle 0}$ intercept remains finite, and can then moderately influence observational constraints through the tensor-to-scalar ratio ($r$).
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High Energy Physics (Phenomenology)
Thermal spectral functions of heavy and exotic Mesons from a hQCD at finite density
Zhou-Run Zhu, Zhanyuan Gao, Zhaohui Feng et al. (+2 more)
In this work, we study spectral functions of heavy and exotic
mesons in a self-consistent Einstein-Maxwell-dilaton model at finite temperature and chemical potential, where the dilaton is allowed to back-react on the geometry. A non-quadratic dilaton profile is introduced to reproduce the nonlinear Regge trajectories of heavy-flavor
mesons, and the corresponding spectral functions are computed for charmonium, bottomonium, tetraquark, and hybrid channels. In all cases, increasing either temperature or chemical potential suppresses and broadens the quasiparticle peaks, signaling sequential in-medium dissociation; for each radial family, the 2S-like state melts before the 1S-like state. The predicted melting temperatures obey the mass ordering $T_{\rm melt}^{\pi_1(1400)}<T_{\rm melt}^{J/\psi}<T_{\rm melt}^{Z_c(3900)}<T_{\rm melt}^{\Upsilon(1S)}$, with $T_{\rm melt}\simeq 1.08,\ 2.96,\ 4.44$, and $5.93\,T_c$, respectively, so heavier states remain bound up to higher temperatures. These results provide quantitative, testable predictions for heavy-ion experiments probing tetraquark and hybrid
mesons in hot and dense QCD matter.
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All authors Zhou-Run Zhu, Zhanyuan Gao, Zhaohui Feng, Man-Li Tian, Defu Hou
High Energy Physics (Phenomenology) · Cross-listed from nucl-th
Binding energies in the $0^{-+}$ and $1^{--}$ fermion–antifermion channels from the ladder Bethe-Salpeter and Schrödinger equations
Wei He and Hai-Qing Zhou
In this work, we calculate the binding energies of an equal-mass
fermion–antifermion system in the $0^{-+}$ and $1^{--}$ channels from the ladder Bethe–Salpeter (BS) equation with scalar, pseudoscalar, and vector exchange. The results are compared with those of the Schrödinger equation with the corresponding leading static interaction in two regimes: pointlike massless exchange at weak coupling and finite-mass exchange with monopole form factors at stronger coupling. For the BS calculation, we use two independent numerical methods based on momentum-space integral equations and coordinate-space differential equations. The differential-equation method gives estimated relative binding-energy errors below $10^{-9}$ in both regimes. For massless vector exchange in Coulomb gauge, the numerical results are consistent with the uncrossed-ladder perturbative spectrum through the $O(m\alpha^5)$ terms. The results for massless scalar exchange and vector exchange in Feynman gauge are consistent with the common Wick–Cutkosky expansion through order $m\alpha^3$. For finite exchange masses, the differences from the leading static Schrödinger spectra at the same masses, couplings, and form factors depend strongly on the exchange and channel. Scalar exchange gives nearly degenerate channels with much weaker binding than the Schrödinger reference. In contrast, vector exchange with only the metric term retained gives stronger binding than the Schrödinger reference in $0^{-+}$ and weaker binding in $1^{--}$. Notably, retaining the full Proca numerator substantially increases the vector binding in both channels. Pseudoscalar exchange also supports bound states and favors $1^{--}$, although its leading static central interaction vanishes.
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High Energy Physics (Phenomenology)
Magnetically Charged Black Holes from Grand Unified Theory
Tanmay Vachaspati and Anja Wachowitz
Grand Unified models of particle physics inevitably give rise to
magnetic monopoles. Often the model will also contain a weakly broken discrete
symmetry that leads to the formation of biased domain walls that survive for a limited period in cosmology. For a range of the discrete
symmetry breaking parameter, domain walls can collapse to form magnetically charged extremal black holes lighter than $\simeq 1\, {\rm kg}$ but these are not expected to survive until the present epoch due to Hawking evaporation and Schwinger pair production of monopoles. If the parameter is smaller still, the black holes may be astrophysical, with mass greater than $10^{15}\, {\rm g}$ and with sub-extremal
magnetic charge: $Q \simeq 10^8$ (for our canonical choice of parameters). The cosmological energy density in residual
magnetic monopoles depends on the discrete
symmetry breaking parameter and for sufficiently small values of the parameter, the
magnetic monopole density can satisfy all observational constraints.
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High Energy Physics (Phenomenology)
Constraints on pion parton distributions at small $x$ from leading-neutron electroproduction data
C. Yang, P. C. Barry, W. Melnitchouk et al. (+1 more)
We revisit the extraction of parton distribution functions (PDFs) in the pion in a global QCD analysis of pion–
nucleus Drell–Yan and leading-
neutron (LN) electroproduction data, in view of recent suggestions that uncertainties on the pion PDFs at small parton momentum fraction $x$ are dramatically underestimated. We perform a set of controlled fits that vary the LN data coverage, PDF parametrization, and positivity constraints, determining both the PDFs and pion-nucleon splitting functions simultaneously. While the use of a restricted H1 LN data sample used by the Fantômas group is found to enlarge the PDF uncertainties and admit solutions with vanishing gluon PDFs, our global analysis provides a good description of an extended H1 and ZEUS LN database, significantly reducing the parametrization dependence and strongly disfavoring a zero gluon distribution.
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All authors C. Yang, P. C. Barry, W. Melnitchouk, N. Sato