Papers

We investigate the Quark-Diquark Model (QDM) with the Functional Renormalization Group (FRG) in the Local Potential Approximation. In a recent work [arXiv:2510.01066 [hep-ph]], problems were reported in applying this method at low temperatures and large quark chemical potentials, which were attributed to numerical artifacts. In this work, we trace the origin of these problems to the occurrence of a negative diffusion coefficient during the FRG flow of the derivative of the effective potential, leading to strong oscillations of the latter quantity. We show that negative diffusion is a model feature and not a numerical artifact. We propose a regularization scheme which introduces a hyperdiffusion term to remove these oscillations and demonstrate its effectiveness for studies of the phase diagram of the QDM. Regularizing the negative diffusion in the FRG flow is particularly important to reliably study phenomena such as color superconductivity and inhomogeneous phases, which might emerge in the high-density, low-temperature region of the QCD phase diagram.

Low-energy lepton-nucleon scattering probes various expressions of the long-distance dynamics in the baryon sector of QCD, governed by chiral symmetry breaking and the $\Delta$ resonance. We discuss some specific studies that could be performed with combined electron- and positron-nucleon scattering at lab energies $E_{e\pm} \lesssim$ 500 MeV. They include: (a) chiral dynamics in the low-$Q^2$ nucleon elastic form factors (peripheral charge and current densities); (b) two-photon exchange effects in the target normal single-spin asymmetry and beam charge asymmetry in elastic and inclusive scattering ($\Delta$ excitation); (c) nucleon generalized polarizabilities in virtual Compton scattering with beam charge asymmetry measurements.

We investigate the specific heat and isentropic bulk modulus of finite-temperature pure SU(3) gauge matter within a lattice-data-driven phenomenological framework. The equation of state is formulated in terms of a temperature-dependent effective gluon mass constrained { by lattice QCD pressure data as input, allowing the pressure}, trace anomaly, gluon number density, energy per thermally active gluonic mode, and derivative-sensitive response functions to be derived in a thermodynamically consistent manner. The resulting pressure and trace anomaly reproduce the characteristic lattice behavior across the deconfinement region, while the effective gluonic degrees of freedom increase rapidly above $T_c$. The normalized specific heat $C_V/T^3$ develops a pronounced enhancement in the vicinity of $T_c$, reflecting the rapid temperature variation of the energy density across the deconfinement region. The isentropic bulk modulus $K_S/T^4$ also rises sharply across the transition region, indicating a substantial stiffening of the equation of state. At high temperatures, both response functions gradually approach values close to their massless conformal Stefan–Boltzmann reference values, with $\left(C_V/T^3\right)_{\rm SB}=32\pi^2/15\simeq 21.06$ and $\left(K_S/T^4\right)_{\rm SB}=32\pi^2/135\simeq 2.34$. These findings indicate that the specific heat and isentropic bulk modulus provide complementary constraints on the temperature evolution of nonconformal dynamics in pure SU(3) gauge matter.

Though quantum computing naturally offers an advantage for simulations of real-time quantum systems, implementing Imaginary-Time Evolution (ITE) is comparatively more difficult. Nevertheless, quantum implementations of ITE are useful both in cases where classical implementations have associated sign problems, and also as an exact method of preparing eigenstates on quantum computers. In this work we present an algorithm to obtain ITE of a generic quantum Hamiltonian by performing analytic continuation of measured real-time correlation functions. We present simulations and demonstrations on IBM quantum hardware of 1D Fokker-Planck equations for classical diffusion process and imaginary-time evolution of integrated correlation functions in 1D quantum mechanical scattering as examples to demonstrate the effectiveness of the method.

Dimensionless observables of neutron stars, such as the moment of inertia, the tidal deformability, the spin-induced quadrupole moment, and the compactness, satisfy the I–Love–Q and Love–$C$ universal relations to percent-level accuracy over a wide range of equations of state. We investigate analytically the origin of this insensitivity in the stellar structure equations. We derive asymptotic expansions of these relations directly from the differential equations and boundary conditions for slowly rotating, tidally deformed stars described by a general piecewise-polytropic equation of state. Although the differential equations allow several forms of the asymptotic expansion, we find that only one class is consistent with the observed universality, and we use this class to analyze the universal relations. Because the observables are determined at the stellar surface, information about the deep-interior equation of state can enter them only through the parameters that survive in the asymptotic expansion at the surface. We find that the universal relations depend only on three parameters: two integration constants and one polytrope index of the outermost segment. By determining how these parameters deform the relations, we show that, throughout the region of parameter space occupied by realistic equations of state, the resulting deviations remain at the percent level, consistent with the observed accuracy of the universal relations. Within the same formalism, we classify violations of universality according to the additional degrees of freedom or input data responsible for them. Since the construction relies only on the underlying differential equations and boundary conditions, the same procedure can be applied to other systems once the corresponding equations and boundary conditions are specified.

We investigate the skewness dependence of the pion generalized parton distribution (GPD) at different momentum transfers $-t$ within the covariant Nambu-Jona-Lasinio (NJL) model, employing the Schwinger proper-time regularization scheme to regulate ultraviolet divergences and implement an effective description of quark confinement. We evolve the pion GPDs for various values of $-t$ and $\xi$ to the scales $\mu^2=4$ and $27~\mathrm{GeV}^2$. We find that the valence-quark distributions are suppressed with increasing $-t$ and $\xi$, with the suppression becoming more pronounced at the lower scale, $\mu^2=4~\mathrm{GeV}^2$. In the forward limit, $\xi=0$ and $-t=0$, the predicted pion valence-quark distribution at $\mu^2=27~\mathrm{GeV}^2$ is in good agreement with the available experimental data and the global JAM analysis. The corresponding pion gluon distribution at $\mu^2=4~\mathrm{GeV}^2$, obtained through next-to-leading-order (NLO) DGLAP evolution, is also consistent with the JAM analysis. We further find that the pion and kaon valence-quark distributions exhibit a strong dependence on $-t$ but only a weak dependence on $\xi$, whereas the corresponding gluon distributions show weak dependence on both $-t$ and $\xi$. The generalized form factors of the pion and kaon at $\mu^2=4~\mathrm{GeV}^2$ are in good agreement with the corresponding lattice-QCD results.

The stability and instability in the time dynamics of quantum fluctuation of the massive gauge field coupling to the nonlinear massive wave solution is studied. In particular, the instability in the transverse polarization and longitudinal polarization modes are obtained as the two dimensional plot of the initial field value parameter and the spatial momentum of the quantum massive gauge fields with the help of the theory of the Hill's equation. We present the formalism to analyze the massive gauge field by taking into account Proca constraint and we found that our formalism can predict the time dynamics of the unstable quantum mode by the Floquet index. The resulting polarization-resolved Floquet maps show that the transverse modes possess only narrow parametric-resonance bands, whereas the longitudinal modes exhibit substantially broader regions generated by both parametric and spinodal instabilities. We also find additional low-momentum instability regions for the $W$ boson that are absent or strongly suppressed in the $Z$ sector.

Quintessential $\alpha$-attractor models of single-field inflation and evolving dark energy were constructed about a decade ago. Recently, it was pointed out that some of them might be disfavored due to dark-radiation constraints on gravitational waves and the higher values of $n_s$ favored by ACT. Here we present a class of updated quintessential $\alpha$-attractor models in which a single field describes both inflation and evolving dark energy, yields higher values of $n_s$, and admits reheating scenarios consistent with the dark-radiation bound on $\Delta N_{\rm eff}$. Depending on the value of the cosmological constant $\Lambda$, these models interpolate between $\Lambda$CDM with $\Lambda > 0$ (future dS universe), dynamical dark energy with $\Lambda = 0$ (future Minkowski universe), and dynamical dark energy with $\Lambda < 0$ (future cosmological collapse). We also study quintessential $\alpha$-attractor models based on an axion-inflaton complex scalar field with hyperbolic geometry, which describe inflation and dark energy of a “phantom illusion” type compatible with DESI DR2.

We use physics-informed neural networks (PINNs) to solve the gravitational quasinormal-mode (QNM) eigenvalue problem for Kerr spacetime directly in the two-dimensional hyperboloidal formulation of the Teukolsky equation. This formulation does not require separation of variables and thus retains the coupled radial–angular structure. Such a scheme provides a prototype for calculating the QNMs of beyond-Kerr black holes for which the perturbation equations are non-separable. Sequences with increasing angular momentum are constructed, reaching close to the extremal limit. We focus on the fundamental modes $(\ell,m,n)=(2,0,0)$, $(2,1,0)$, $(2,2,0)$, $(3,3,0)$ and $(4,4,0)$, together with the first overtone $(2,2,1)$. Independent benchmark evaluation shows that every reported real and imaginary frequency component remains below $0.5\%$ error, with a median deviation of $0.1\%$. This accuracy is maintained in the near-extremal regime, where the damping rate becomes small and the modes are longest-lived. The results establish a non-spectral numerical route to multidimensional black-hole perturbation eigenproblems which does not match the substantially higher precision of dedicated Kerr solvers but offers greater flexibility and requires less analytical pre-processing. Non-separable rotating backgrounds and coupled systems, such as gravitational–electromagnetic Kerr–Newman perturbations, are natural extensions of the same construction.

We show that color triality constrains the nonperturbative states that screen a Wilson-line endpoint, allowing the joint flows of net electric charge, baryon number, and strangeness to probe QCD vacuum hadronization. Whether evaluated from resolved hadrons in a jet initiated by a quark of flavor $f$ or from the corresponding charge correlators, these flows satisfy the Gell-Mann–Nishijima relation $\langle Q_{\rm flow}\rangle_f \simeq I_{3,f} +\frac{1}{2}\left( \langle S_{\rm flow}\rangle_f +\langle B_{\rm flow}\rangle_f \right)$, where $I_{3,f}$ is the third component of the initiating-quark isospin. The net jet baryon number, $\langle B_{\rm flow}\rangle_f\simeq \frac{r_{qq}}{1+r_{qq}}$, directly probes the relative probability of a diquark–antidiquark vacuum excitation, with $r_{qq}$ the diquark-to-quark production ratio. Thus, for $r_{qq}\ll1$, the baryon number carried by the jet is substantially suppressed relative to the initiating-quark value $B_f=1/3$. Likewise, the strange-to-light pair-production ratio, defined by $u\bar u:d\bar d:s\bar s=1:1:r_s$, is encoded in the measured jet strangeness $\langle S_{\rm flow}\rangle_f \simeq S_f+\frac{3r_s}{2+r_s} \left(\frac{1}{3}- \langle B_{\rm flow}\rangle_f\right)$, predicting a nonzero mean net strangeness even in $u$- and $d$-initiated jets. The conserved-current moments appearing in these relations are independent of the renormalization scale. Their simultaneous measurement therefore provides a direct, flavor-resolved probe of vacuum pair production and quantum-number transport during hadronization.

We propose a minimal three-family realization of quark–lepton complementarity (QLC) in which the non-trivial correlation matrix is an exactly unitary, rigid deformation of tri-bimaximal mixing. In a canonical TBM convention the deformation is a rotation about the normalized axis $n_{gg}=(2,1,2)^T/3$, with rotation angle fixed by the Cabibbo angle, $\alpha_{gg}=-3\theta_C/4$. The resulting ansatz, $\UPMNS=\VCKM^\dagger\UTBM R_{n_{gg}}(-3\theta_C/4)$, contains no new continuous parameter in the Dirac lepton-mixing sector once the structural choice is fixed. With the 2025 Particle Data Group CKM fit it predicts $\theta_{12}=33.29^\circ$, $\theta_{13}=8.46^\circ$, $\theta_{23}=49.19^\circ$, and $\dcp=180.79^\circ$, with CKM-induced uncertainties much smaller than present oscillation errors. We derive leading Wolfenstein sum rules; in particular, the real deformation preserves the CKM-induced suppression $\Jcp=-A\eta\lambda^3/6+\mathcal O(\lambda^4)$ and hence a near-CP-conserving phase. A retrospective simplicity scan shows that the pair $(2,1,2),3/4$ ranks first among 5510 oriented primitive-integer/rational candidates when tested on epoch-matched 2016 and 2018 oscillation data. In an enlarged 49,622-candidate 2018 scan it is second in raw score but remains first among candidates no more complex than itself under several independent simplicity measures; profiling the rotation strength for the fixed $(2,1,2)$ axis gives $r_{\rm BF}=0.74941$. We formulate the deformation by a convention-covariant flavor-space generator and give an exact effective eigenframe realization $M_\nu=A I+B\Sgg+C\Sgg^2$. The construction is presently allowed in normal ordering, with the atmospheric sector providing its strongest pressure; its upper-octant atmospheric angle and near-$\pi$ Dirac phase provide sharp falsifiability targets.

The CMS and ATLAS Collaborations have reported a $t\bar{t}$ threshold enhancement possibly involving a pseudoscalar toponium quasi-bound state and an elementary pseudoscalar. Identifying the elementary pseudoscalar with the CP-odd Higgs boson, we investigate electroweak baryogenesis in the top-philic Type-III two-Higgs-doublet model (2HDM), whose scalar sector may support a strong first-order electroweak phase transition. We compare two scenarios: explicit CP violation and transitional CP violation (TCPV). In the first, a complex additional top-quark Yukawa coupling induces a spatially varying phase of the top-quark mass across the bubble wall. This generates a chiral asymmetry that electroweak sphalerons convert into baryon asymmetry. In TCPV, CP symmetry would be broken inside the bubble wall but preserved in the vacuum in the absence of explicit CP violation. A small explicit CP-violating bias would favor one of the otherwise CP-conjugate wall configurations, avoiding exact cancellation of the generated baryon asymmetry. This could allow baryogenesis without large explicit CP violation, potentially alleviating electric dipole moment constraints. Combining a one-loop finite-temperature analysis of bubble nucleation with transport calculations, we find that electroweak baryogenesis with explicit CP violation remains possible, although this conclusion depends on the thermal-resummation schemes. No viable TCPV solution is found in the parameter regions explored.

Since all the Standard Model (SM) parameters have been measured to precision at the percent level or smaller, one would aim to have a framework which describes baryogenesis as precise as possible, where the measured SM parameters are used as inputs. At high temperature before the electroweak symmetry breaking, the SM contains 15 approximate $U(1)$ symmetries with the associated flavor charges. To describe the evolutions of these flavor charges in a flavor-basis-covariant manner such that physical observables are flavor-basis-independent, a total of five density matrices in flavor spaces are required: three for quarks and two for leptons. Taking into account the quantum chromodynamics and electroweak sphaleron interactions together with all the Yukawa interactions, we obtain the complete flavor-covariant Boltzmann equations. By imposing chemical equilibrium in the lepton sector, we further derive a new effective quark-flavor-covariant formalism which can be used when baryogenesis occurs through number asymmetry generation in the quark sector. To verify the consistency of this complete formalism, we first apply it to leptogenesis scenarios, reproducing previous results which utilize the effective lepton-flavor-covariant formalism up to small corrections due to the quark chemical equilibrium approximations used in the latter formalism. Then, for the first time, we apply the complete formalism as well as the effective quark-flavor-covariant formalism to a cloistered baryogenesis scenario where number asymmetries are generated in the quark sector, showcasing the good agreement between the results from the two formalisms. Finally, we release the first generic baryogenesis public code BOLEH (BaryOn and Lepton charge Evolution in the Hot big bang) where all the SM interactions are taken into account.

We study the bremsstrahlung photon production from a hard jet parton induced by rescattering with a dense nuclear medium. Using the charged current interaction channel of deep inelastic scattering between an electron and a large nucleus, we derive the spectrum of medium-induced photons emitted from high-energy heavy and light quarks at the next-to-leading twist in a unified framework. Going beyond the collinear expansion approximation, we show that the photon spectrum is determined by the full momentum distribution of the gluon exchanged between the propagating quark and the medium, or equivalently, by the differential elastic scattering rate of the hard quark inside the medium. Modeling the gluon field with a static Debye screened potential reduces the photon spectrum to a dependence on the transverse momentum distribution of the exchanged gluon. This work provides a more reliable input for future phenomenological studies of quark mass effects on jet-induced photon production in relativistic heavy-ion collisions.

We study a non-standard cosmology (NSC) scenario within the Unimodular Gravity (UG) framework, sourced by a scalar field $\phi$ that undergoes energy diffusion, parametrized by the diffusion parameter $x$, the initial energy densities rate $\kappa\equiv\rho_\phi/\rho_\gamma|_{\text{ini}}$, and the end-of-domination temperature $T_{\text{end}}$. We compare this UG+NSC scenario with standard NSC and $\Lambda$CDM cosmologies for WIMP Dark Matter (DM) production via the freeze-out mechanism. We find that energy diffusion reshapes the allowed $(m_\chi, \langle\sigma v\rangle)$ parameter space, where $m_\chi$ is the DM mass and $\langle \sigma v \rangle$ is the thermally averaged annihilation cross section, opening regions otherwise excluded by DM overproduction in $\Lambda$CDM, and shifting the mass and cross-section ranges accessible to WIMP candidates depending on $x$, $\kappa$, $T_{\text{end}}$, and the barotropic index $\omega$ of $\phi$. As a concrete application, we implement this framework for the Real Singlet Scalar WIMP and test its $(m_\chi, \lambda_{HS})$ parameter space against current direct detection bounds from the LZ experiment, showing that energy diffusion opens previously unconstrained regions in the Higgs-portal coupling $\lambda_{HS}$ and thereby alters the detectability prospects of this benchmark model in future searches.

Cosmic superstrings are well-motivated early-Universe sources of stochastic gravitational waves, with phenomenology controlled by the string tension $G\mu$ and the intercommutation probability $P$. We study whether LISA can reconstruct these parameters and distinguish different superstring signal models in the presence of instrumental noise and astrophysical foregrounds. We consider two phenomenological models. In Model I, reduced intercommutation acts only as an amplitude enhancement of a cusp-dominated spectrum, $\Omega_{\rm SS}^{\rm I}=P^{-\beta}\Omega_{\rm cusp}$. In Model II, the signal is a cusp–kink mixture, $\Omega_{\rm SS}^{\rm II} =P^{-\beta}[p_c\Omega_{\rm cusp}+(1-p_c)\Omega_{\rm kink}]$, so that $P$ controls both amplitude and spectral shape. Using simulated LISA data, we perform Bayesian inference with noise uncertainties, unresolved extragalactic compact-binary backgrounds, and a flexible Galactic double-white-dwarf foreground. We compare the models using Bayesian evidences and map the $(G\mu,P)$ posterior geometry with marginalized widths, correlations, covariance anisotropy, principal eigenvalues, posterior area, and bias. We find that reduced intercommutation generically produces strong $G\mu$–$P$ correlations, because the data often constrain an amplitude-like combination. However, when the cusp–kink spectral difference lies in the LISA band and the signal is sufficiently loud, Model II can be favored and the posterior can retain genuine shape information. As an optimistic foreground scenario, we also compute the Bayes factor using a reduced tanh Galactic foreground template, finding improved model discrimination when the foreground shape is constrained.

We develop a stochastic formulation of the Schwinger effect in de Sitter spacetime using the Schwinger–Keldysh (in-in) formalism, tailored to particle production by non-stationary gauge backgrounds in the early Universe. Treating the gauge field as a prescribed classical stochastic ensemble, we integrate out massless charged matter and derive the corresponding influence functional and particle-production kernel to leading non-trivial order in the gauge coupling. Conformal invariance allows the result to be extended directly from de Sitter to generic spatially flat FLRW spacetimes, without relying on asymptotic out states. We establish the infrared safety and classicality conditions of the stochastic description and clarify its relation to the conventional static Schwinger effect. We further extend the framework to massless conformally coupled scalars and to weakly coupled non-Abelian gauge sectors, including Standard Model and hidden-sector examples, in regimes where thermal corrections are negligible. Our results provide a general framework for matter creation by stochastic gauge fields in inflation, preheating, and non-thermal BSM sectors, connecting quantum field theory in curved spacetime with early-Universe and high-energy phenomenology.

We study leptogenesis via out-of-equilibrium decays of right-handed neutrinos in a parity symmetric extension of the Standard Model with gauge group $SU(3)_c \times SU(2)_L \times SU(2)_R \times U(1)_X$, spontaneously broken to the Standard Model gauge group at a scale $v_R$. We focus on the minimal Higgs realization, in which the strong CP problem is resolved without invoking additional symmetries. In this framework, lepton number is violated through Yukawa interactions, while neutrino masses arise only at higher loop order, a feature that permits the CP-violating quantum corrections to right-handed neutrino decays to be parametrically large. For thermal production of right-handed neutrinos, we find that successful leptogenesis requires $v_R \gtrsim 6\times 10^{12}$ GeV. Non-thermal production, however, relaxes this bound dramatically, requiring only $v_R \gtrsim 10$ TeV, a scale accessible to collider searches for new particles and searches for rare processes.

We present the first application of the unbiased exponential resummation method to the determination of the QCD pseudocritical temperature $T_{\rm pc}$ at vanishing baryon chemical potential $\mu_B$. By reconstructing the finite-density baryon number susceptibility $\chi_2^B$, we define two thermal-derivative observables whose peak positions yield $T_{\rm pc}^T=160.2(4)(3)$ MeV and $T_{\rm pc}^C=158.1(5)(3)$ MeV. We also show that the pseudocritical temperature, $T_{\rm pc}^\chi$ obtained from the peak of the fourth-order baryon number susceptibility $\chi_4^B$ is consistent with these determinations and with previous lattice-QCD results based on Taylor expansions \cite{Bollweg:2022Pade}. Further, we demonstrate that scaling relations \cite{Bollweg:2022fqq} between $\chi_4^B$ and the thermal derivatives of $\chi_2^B$ yield mutually consistent estimates of the leading second order curvature coefficient $\kappa_2^B$ at the corresponding pseudocritical temperatures. A direct analysis of the $\mu_B$ dependence of the pseudocritical temperatures provides an independent but substantially less constrained determination of the curvature, which remains statistically consistent with the scaling-based estimates. These results demonstrate the consistency of unbiased exponential resummation with the expected scaling behavior and establish it as a complementary approach for probing the QCD crossover at small finite baryon density.

We study the constraints placed by energy positivity on general unitary quantum field theories. We show that the coefficients in the partial wave expansion of energy-energy correlators all must lie within a bounded region of parameter space, which we call the “EEC-hedron”. For the particular case of conformal field theories, these positivity constraints on energy correlators lead to bounds on the allowed values of coefficients in the operator product expansion. We demonstrate this approach in the 3d Ising and $O(2)$ CFTs, deriving new bounds on OPE coefficients in both theories.

Dark matter subhalos leave gravitational imprints in the stellar streams of the Milky Way. Observing individual strong impacts of subhalos offers a compelling way to constrain and discover potentially dark subhalos down to $10^6 M_\odot$, allowing for new tests of the particle physics properties of dark matter. We develop a pipeline and statistical framework to forecast the expected number of detectable subhalo impacts on stellar streams, based on morphological and kinematic data from surveys such as LSST and Via. Starting from a catalog of confirmed stellar streams, we focus our efforts on 14 promising streams that are relatively well-modeled with a particle spray algorithm. Our criteria for a detectable impact is a deviation at 95% CL from the best-fit polynomial proxy model for the stream, which accounts for stream modeling uncertainties and regulates the effect of distant impacts that are degenerate with these uncertainties. Among the 14 streams studied, we find that 5 streams have an expected number of detectable impacts greater than 0.2. With LSST and Via data, the stream Jet has $5.15^{+1.10}_{-0.95}$ expected detectable impacts, followed by Orphan-Chenab ($1.40^{+0.62}_{-0.47}$), ATLAS-Aliqa Uma ($1.25^{+0.60}_{-0.44}$), GD-1 ($0.55^{+0.43}_{-0.28}$), and Palomar 5 ($0.40^{+0.39}_{-0.23}$), where error bars are the 95% containment on the Poisson mean. These values rely on the assumed subhalo population, which can give a factor of few systematic uncertainty in the predictions. We also consider effects of different particle dark matter models on the number of impacts, finding a suppression by a factor of $\sim 4$ for warm dark matter and fuzzy dark matter models at their current mass bounds and an $O(1)$ enhancement for a toy model of self-interacting dark matter.

The mixing of heavy neutral leptons (HNLs) with tau neutrinos remains largely unconstrained compared to their mixing with electron and muon neutrinos. In this work, we investigate the potential of solar neutrinos to improve constraints on HNL-$\nu_\tau$ mixing in the MeV mass range. Due to neutrino oscillations, the Sun is a copious source of neutrinos of all flavors, and the partial conversion of electron neutrinos into muon and tau neutrinos occurs already during their propagation through the solar interior. Tau neutrinos can produce HNLs through scattering with protons in the Sun, provided nonzero HNL-$\nu_\tau$ mixing is present. The HNLs escape the Sun and subsequently decay through the same interaction. For $\mathcal{O}(10)$ MeV HNL masses, the dominant visible decay yields electrons and positrons that can be detected by space-based solar observatories. Using data from the Solar and Heliospheric Observatory (SOHO), we search for such signals and derive constraints on the squared HNL-$\nu_\tau$ mixing matrix element, $|U_{\tau N}|^2$, reaching below the $10^{-2}$ level for HNL masses of $\sim 5$ MeV. These constraints improve upon existing terrestrial limits in this mass range by more than an order of magnitude.

Searches for new physics using neural anomaly scores have transformative potential, but suffer from a lack of statistical interpretability. The normalized autoencoder (NAE) provides a probabilistic interpretation of the standard bottleneck architecture, tying the anomaly score to a learned likelihood. We validate this relation for a toy model, test it for jets using a dual-NAE setup, and show how a Bayesian NAE learns this likelihood with an uncertainty.

The complete one- and two-loop gauge and scalar current–current contributions to the running of arbitrary dimension-six four-fermion operators are reported. The results are obtained in a basis-independent and renormalization-scheme-agnostic fashion and are valid for arbitrary gauge groups. The complete gauge and scalar contributions, including the genuine one- and two-loop poles, counterterm insertions, wave-function renormalization, finite evanescent insertions, diagram multiplicities, and the associated color, charge and Yukawa factors are provided for the most general renormalizable Lagrangian with gauge and scalar interactions. The results enable the derivation of leading- and next-to-leading-order current–current anomalous-dimension matrices for arbitrary Effective Field Theories (EFTs) and constitute a significant step toward the complete two-loop renormalization of general EFTs.

The dynamics of heavy quarks in quark-gluon plasma (QGP) formed in heavy ion collisions provide a unique window to characterize its properties. Existing approaches to describe heavy quarks in medium rely either on quasiparticle-based models of QGP, or on assuming that the momentum transfer from the medium follows Gaussian statistics. However, neither of these assumptions can be taken for granted in QCD. In fact, in the prototypical theory that is strongly coupled $\mathcal{N}=4$ SYM, it has been long known there are no momentum-carrying quasiparticles, and furthermore, we have recently shown that the momentum transfer from the medium is far from being Gaussian [arXiv:2501.06289]. Since then, we showed that the asymmetry of said momentum transfer between energy loss and energy gain – which affects all moments of the distribution, not only its Gaussian characteristics – is, in fact, universal [arXiv:2504.21139]. Therefore, in order to connect the initial heavy quark production cross section with the final hadron spectrum in a way that is consistent with QFT principles, new methods are needed. In this talk, we present a new transport description of heavy quarks that encodes all of the non-Gaussian features of the momentum transfer from the medium, all of which can be defined and in principle calculated in QCD, without relying on any assumptions regarding the strength of the coupling. As a demonstrative example, we discuss heavy quark equilibration in $\mathcal{N}=4$ SYM. This paves the way towards extracting novel information about fundamental properties of QGP.

We revisit a proposed correction to the muon magnetic anomaly measurement and compare it with energy-binned scans reported by the Fermilab $g-2$ collaboration. The central point is that, for a relativistic three-body decay inferred from an ensemble of detected positrons, the relevant neutrino partial trace is defined on the asymptotic state at the detector, not on an idealised state at the decay vertex. Because the fitted positron sample mixes events with different decay times, flight times, energies and acceptances, tracing over the unobserved neutrino helicities leaves a time-dependent mixed state in the observed sector. Using angular-momentum balance, we obtain an energy-dependent correction in the positron energy interval $E_p \in (1.5,2.9)$ GeV. The corrected experimental interval for the muon anomaly moves towards the BaBar- and $\tau$-based determinations, while remaining compatible at the $1\sigma$ level with both data-driven and lattice-based Standard Model evaluations. We then fit digitised public $R(E_p)$ scans for Fermilab's runs $1$ to $6$, with two one-parameter hypotheses: a constant shift and the entanglement-motivated energy-dependent shift. Within digitisation accuracy, the differences in $\chi^2$ remain modest and the current binned data do not provide decisive discrimination between them.

Quantum magic, or nonstabilizerness, is a quantum resource associated with computational advantage in quantum systems. In high energy collisions, Quantum Electrodynamics (QED) is inefficient at generating magic while the weak mixing angle, a fundamental constant of nature, sits near a value that minimizes magic production in charged-lepton scattering. These observations were made in the laboratory (lab) basis, in which spin is projected along the incoming beam axis. An alternative choice is the helicity basis, in which spin is projected along the direction of motion of each particle. The transformation between these two bases is, in general, not a Clifford operation and therefore can change the amount of magic. We present a detailed study of magic production in both bases for QED and electroweak processes, and compare these results with the basis-invariant non-local magic. In the ultra-relativistic limit, magic production is generally smaller in the helicity basis due to helicity selection rules, while the lab basis generally yields less magic in the non-relativistic regime. We provide circuit realizations of the ultra-relativistic Bhabha amplitudes using linear combinations of unitaries and show that the lab basis construction contains a larger $T$-gate count at generic scattering angles. Interestingly, in both bases the physical weak mixing angle lies close to the value that minimizes magic production.

The large-scale structure of the universe has the potential to probe anomalies suggested by observations of the cosmic microwave background. In this work, we focus on a position-dependent dipolar modulation of the primordial power spectrum and develop a full-sky formalism for computing correlation functions of galaxy density, velocity and ellipticity. By comparing the correlation functions obtained with and without the plane-parallel approximation, we show that wide-angle corrections become non-negligible for opening angles $\Theta \gtrsim 30^\circ$. Our results demonstrate that wide-angle corrections must be taken into account when testing the dipolar modulation with future large-scale structure surveys.

We investigate uncertainty quantification for the neutron-star equation of state (EOS) by comparing point-estimation and distributional inference approaches using the same Chebyshev and piecewise-linear parameterizations. We combine neutron-star mass–radius and gravitational-wave tidal-deformability information within Bayesian, multilayer-perceptron (MLP), and normalizing-flow frameworks. Although the methods yield similar mean EOS behavior, the deterministic MLP produces substantially narrower uncertainty bands at high densities. We show that this behavior is associated with the point-estimation objective, which maps degenerate solutions toward the conditional mean rather than representing the full parameter posterior. By contrast, the normalizing flow yields distributions more consistent with the Bayesian inference. Our results demonstrate that reliable uncertainty quantification of the high-density EOS requires methods that represent conditional probability distributions rather than only point estimates.

QCD, the theory of the strong interactions, is formulated in terms of quarks and gluons, while low-energy nuclear physics deals with hadrons such as protons, neutrons, and pions. Symmetries establish a systematic connection between these two descriptions of strongly-interacting systems. The objective of this article is to review the symmetries of QCD and to explain how they constrain hadronic interactions. Chiral symmetry, which emerges in QCD in the limit of massless quarks, is of particular importance for low-energy nuclear physics. Together with its explicit and spontaneous breaking, chiral symmetry provides the basis for chiral perturbation theory, the effective field theory describing pions and nucleons at low energies.