Tue·Feb 4, 2025Tuesday·February 4, 2025

1. 01*

   Analytic two-loop amplitudes for $q\bar{q}\to \gamma \gamma$ and $gg\to \gamma \gamma$ mediated by a heavy-quark loop

   Matteo Becchetti🇮🇹 · Federico Coro🇧🇪 · Christoph Nega🇩🇪 · Lorenzo Tancredi🇩🇪 · Fabian J. Wagner🇩🇪

   We address the analytic computation of the two-loop scattering amplitudes for the production of two photons in parton-parton scattering, mediated by loops of heavy quarks. Due to the presence of integrals of elliptic type, both partonic channels have been previously computed using semi-numerical methods. In this paper, leveraging new advances in the theory of differential equations for elliptic Feynman integrals, we derive a canonical basis for all integrals involved and compute them in terms of independent iterated integrals over elliptic and polylogarithmic differential forms. We use this representation to showcase interesting cancellations in the physical expressions for the scattering amplitudes. Furthermore, we address their numerical evaluation by producing series expansion representations for the whole amplitudes, which we demonstrate to be fast and numerically reliable across a large region of the phase space.

   hep-phhep-thJHEP(2025)·30 citations
2. 02*

   Electroweak baryogenesis from charged current anomalies in $B$ meson decays

   Peter Athron🇨🇳 · Michael J. Ramsey-Musolf🇺🇸 · Cristian Sierra🇨🇳 · Yongcheng Wu🇨🇳

   We demonstrate for the first time that new physics explaining the long standing charged $B$ meson anomalies, $R(D^{(\ast )})$, can be the source of CP violation that explains the observed baryon asymmetry of the universe (BAU). We consider the general two Higgs doublet model with complex Yukawa couplings and compute the BAU in the semiclassical formalism, using a novel analytic approximation for the latter. After imposing constraints from both flavor observables and the electron electric dipole moment (eEDM), we find that a significant BAU can still be generated for a variety of benchmark points in the parameter space, assuming the occurrence of a sufficiently strong first order electroweak phase transition. These scenarios, which explain both the $R(D^{(\ast )})$ flavor anomalies and the BAU, can be probed with future eEDM experiments and Higgs factories measurements.

   hep-ph7 citations
3. 03*

   Local form factor subtraction for three-loop QCD corrections to electroweak production in quark-antiquark annihilation

   Rayan Haindl🇩🇪

   We extend a local subtraction framework to three-loop QCD corrections for the production of multiple electroweak bosons in quark-antiquark annihilation. We derive two-loop Ward identities that ensure the factorisation of most collinear singularities from the hard-scattering process in the sum over integrands. Infrared and ultraviolet singularities are removed point-by-point in loop momentum space using a minimal set of counterterms, which can be integrated analytically in terms of known master integrals. Additional counterterms eliminate non-factorising terms arising from loop momentum shifts and one-loop corrections to the gluon three-point function. We identify previously unknown non-factorising loop polarisation effects in the single-collinear regions, which pose challenges for local integrability and require further investigation. The techniques presented here are a first crucial step in formulating a systematic approach for constructing finite integrands for general electroweak amplitudes at three-loop order.

   hep-phJHEP(2025)·4 citations
4. 04*

   Starobinsky Inflation with T-Model Kaehler Geometries

   C. Pallis🇬🇷

   We present novel implementations of Starobisky-like inflation within Supergravity adopting Kaehler potentials for the inflaton which parameterize hyperbolic geometries known from the T-model inflation. The associated superpotentials are consistent with an R and a global or gauge U(1)_X symmetries. The inflaton is represented by a gauge-singlet or non-singlet superfield and is accompanied by a gauge-singlet superfield successfully stabilized thanks to its compact contribution into the total Kaehler potential. Keeping the Kaehler manifold intact, a conveniently violated shift symmetry is introduced which allows for a slight variation of the predictions of Starobinsky inflation: The (scalar) spectral index exhibits an upper bound which lies close to its central observational value whereas the constant scalar curvature of the inflaton-sector Kaehler manifold increases with the tensor-to-scalar ratio.

   hep-phastro-ph.COhep-thUniverse(2025)·4 citations
5. 05*

   Charge sum rules for quark fragmentation functions

   D. Kotlorz🇷🇺 · O. V. Teryaev🇷🇺

   Charge sum rules for quark fragmentation functions are studied. The simultaneous implementation of the conservation of electric and baryon charges, strangeness and isospin symmetry is achieved when the fragmentation to both mesons and baryons is considered. The results are compatible to Gell-Mann--Nishijima formulas and may be the new manifestation of superconformal symmetry between mesons and baryons. The numerical estimates are performed and compared with phenomenological models. The recently suggested violations of sum rules due to Wilson lines contributions are discussed.

   hep-phhep-thPRC(2025)·2 citations
6. 06*

   Lorentz-violating pseudovectors in effective field theories for quantum gravity

   Hollis Williams🇬🇧

   Effective field theories which describe the coupling between gravity and matter fields have recently been extended to include terms with operators of non-minimal mass dimension. These terms preserve the usual gauge symmetries but may violate local Lorentz and diffeomorphism invariance. The number of possible terms in the field theory explodes once one allows for non-minimal operators, with no criterion to choose between them. We suggest as such a criterion to focus on terms which violate Lorentz invariance via a (pseudo)vector background field, leaving a number of possible terms in the Higgs, gauge and gravitational sectors. Further study of these terms is motivated by the proposed correspondence between the general effective theory for Lorentz violation and emergent Lorentz symmetry in condensed-matter systems, which is mostly unexplored for higher mass dimension operators and couplings to gauge fields and gravity. We suggest bounds in the Higgs sector and we show that some of the coefficients in the gauge sector vanish at one loop, whereas others have bounds which are comparable with those suggested by Kostelecký and Li for coefficients in Lorentz-violating QCD and QED coupled to quarks. We also find new bounds in the gravitational sector by considering Robertson-Walker cosmology. Finally, we discuss the special case where only diffeomorphism invariance is spontaneously broken and explain why it does not allow for non-trivial Nambu-Goldstone modes.

   hep-phhep-thActa Phys.Polon.B(2024)·2 citations
7. 07*

   Background-field method and QCD factorization

   Ian Balitsky🇺🇸

   One method for deriving a factorization for QCD processes is to use successive integration over fields in the functional integral. In this approach, we separate the fields into two categories: dynamical fields with momenta above a relevant cutoff, and background fields with momenta below the cutoff. The dynamical fields are then integrated out in the background of the low-momentum background fields. This strategy works well at tree level, allowing us to quickly derive QCD factorization formulas at leading order. However, to extend the approach to higher loops, it is necessary to rigorously define the functional integral over dynamical fields in an arbitrary background field. This framework was carefully developed for the calculation of the effective action in a background field at the two-loop level in the classic paper by Abbott [1]. Building on this work, I specify the renormalized background-field Lagrangian and define the notion of the quantum average of an operator in a background field, consistent with the ``separation of scales'' scheme mentioned earlier. As examples, I discuss the evolution of the twist-2 gluon light-ray operator and the one-loop gluon propagator in a background field near the light cone.

   hep-phActa Phys.Polon.B(2025)·2 citations
8. 08*

   Investigating Notions of Entropy and Its Production in High Energy Particle Collisions

   G. S. Ramos🇧🇷

   This work analyzes different notions of entropy and its production in $ep$ and heavy-ion collisions, focusing on the early stages of the collision. To this end, the importance of phenomena such as quantum entanglement and decoherence in entropy generation was studied. Using state-of-the-art methods for calculating entanglement entropy in the high-energy limit and synthesizing various approaches for its computation, phenomenological results were obtained from analytical expressions for the number of gluons. Results were also presented for the entanglement entropy in two-body elastic scattering based on the hadronic structure given by the model-independent Lévy method, at energy values typical of the RHIC, Tevatron, and LHC. Phenomenological models of unintegrated gluon distributions were used to calculate dynamic entropy in the QCD of dense gluonic states in $pp$ and $pA$ collisions at high energies, comparing it with decoherence entropy. The obtained results were contrasted with other notions of entropy in the literature, and theoretical uncertainties were discussed.

   hep-ph1 citation
9. 09*

   Study of the mass spectra of doubly heavy ${\Xi }_{Q{Q}^{\prime }}$ and ${\Omega }_{Q{Q}^{\prime }}$ baryons

   Ji-Hai Pan🇨🇳 · Ji-Si Pan🇨🇳

   LHCb Collaboration first observed a doubly charmed baryon ${\Xi }_{cc}^{++}$ in the ${\Lambda }_c^{+}{K}^{-}{\pi }^{+}{\pi }^{+}$ decay with a mass of $3621.40\pm 0.72\pm 0.27$ MeV. In this paper, we enumerated the mass spectra of the radial and orbital excited states for the doubly heavy ${\Xi }_{Q{Q}^{\prime }}$ and ${\Omega }_{Q{Q}^{\prime }}$ baryons using the Regge trajectory model and the scaling rules. Our studies suggest that ${\Xi }_{cc}^{++}$ can be grouped into the $1S$-wave state with the spin-parity quantum number $J^P=1/2^{+}$. On the other hand, the mass of ${\Xi }_{cc}$ state with $J^P=3/2^{+}$ is predicted to be $3699.69\pm 4.59$ MeV. We also predict the mass spectra of the unknown ground and excited states for the doubly heavy ${\Xi }_{Q{Q}^{\prime }}$ and ${\Omega }_{Q{Q}^{\prime }}$ baryons, which provide useful references for the experimental test in the future.

   hep-phEPJC(2025)·2 citations
10. 10*

    Constraining the CME in AVFD-simulated heavy-ion collisions using the Sliding Dumbbell Method

    Jagbir Singh🇮🇳 · Anjali Sharma🇮🇳 · Ankita Nain🇮🇳 · Madan M. Aggarwal🇮🇳

    The Anomalous Viscous Fluid Dynamics (AVFD) framework is utilized to generate ${}_{79}^{197}Au{+}_{79}^{197}Au$, ${}_{44}^{96}Ru{+}_{44}^{96}Ru$, and ${}_{40}^{96}Zr{+}_{40}^{96}Zr$ collision events at $\sqrt{s_{\mathrm{NN}}}$ = 200 GeV to investigate the Chiral Magnetic Effect (CME). The CME signal is modulated through the axial charge per entropy density ($n_5/s$) in each event to produce data sets with varying CME signal strengths. Additionally, a 33$\%$ local charge conservation (LCC) is implemented in each event. These data sets are analyzed using CME-sensitive two- and three-particle correlators. Furthermore, the Sliding Dumbbell Method (SDM) is employed to identify potential CME-like events within each data set. The identified events selected using the SDM exhibit characteristics consistent with CME. The CME fraction in these events is quantified while accounting for background contributions.

    hep-phnucl-thEPJA(2026)·0 citations
11. 11*

    A model calculation of the CKM matrix

    Maurizio Firrotta🇬🇷 · Giancarlo Rossi🇮🇹

    We propose a strategy to compute the CKM matrix based on the conjecture, recently put forward in the literature, according to which elementary particle masses are not generated like in the standard Higgs scenario, but emerge from a non-perturbative mechanism triggered by the presence in the fundamental Lagrangian of ``irrelevant'' chiral breaking operators of the Wilson type of dimension $d\ge 6$ scaled by $d-4$ powers of the UV cutoff. Non-perturbatively generated quark masses have the form $m_q\sim C_q(\alpha ){\Lambda }_{RGI}$ where ${\Lambda }_{RGI}$ is the RGI scale of the theory and $C_q(\alpha )$ is a function of the gauge couplings. For the (elementary) fermion $q$ the $C_q(\alpha )$ leading behaviour is $C_q(\alpha )=\text{mbox}O({\alpha }^{1+(d_q-4)/2})$. The dependence of the gauge coupling power behaviour from the dimension $d_q$ of the Wilson-like operators associated with the fermion $q$ can be exploited to construct hierarchically organized up and down ''proto-mass matrices'' for ''proto-flavours'', the diagonalization of which yields flavoured quarks with definite masses and a first principle construction of the CKM matrix.

    hep-ph0 citations
12. 12*

    The Aharonov-Bohm effect for a constant scalar matter potential in neutrino flavour interferometry

    J. Bernabeu🇪🇸 · C. Espinoza🇲🇽

    The Aharonov-Bohm effect is one of the most surprising wonders of the quantum world. The observed solenoid effect, as well as others, shows that a particle is affected by the potential in a region in which there is no force-field. This is so through the phase of the probability amplitude. Its interpretation is debated between a physical significance of the potential versus non-locality of quantum physics with the presence of the force-field generated by the potential difference outside this region. We demonstrate that the debate is resolved with the idea of replacing spatial interference by flavour interferometry as observed in neutrino oscillations. The neutrino propagation through the crust of the Earth in current facilities is affected by a constant scalar matter potential and the phase difference is in flavour internal properties. Here we show how to signal and experimentally disentangle the phase-shift due to the potential by means of observables characteristic of its symmetry properties. The energy dependence of the neutrino-antineutrino asymmetry in the golden transition ${\nu }_{\mu }\to {\nu }_e$ allows a clear separation of the matter component against the genuine asymmetry in the absence of the potential. These findings define, in a perfect symbiosis between quantum physics and particle physics, the path to observe in a single experiment the physical significance of the potential, the neutrino mass hierarchy and the genuine matter-antimatter asymmetry in the lepton sector.

    hep-phquant-phPRL(2026)·0 citations
13. 13*

    Thrust distribution in electron-positron annihilation at full NNNLL+NNLO (and beyond) in QCD

    Ugo Giuseppe Aglietti🇮🇹 · Giancarlo Ferrera🇮🇹 · Wan-Li Ju🇮🇹 · Jiahao Miao🇮🇹

    We consider the thrust ($T$) distribution in electron-positron ($e^{+}{e}^{-}$) annihilation into hadrons and we perform the all-order resummation of the large logarithms of $1-T$ up to next-to-next-to-next-to-next-to-leading logarithmic (N${}^4$LL) accuracy in QCD. We consistently combine resummed predictions with the known fixed-order results up to next-to-next-to-leading order (NNLO). All perturbative terms up to order ${\alpha }_S^3$ are included in our calculation which, thanks to a unitarity constraint, exactly reproduce after integration over the variable $T$ the next-to-next-to-next-to-leading order (N${}^3$LO) result for the total cross section of $e^{+}{e}^{-}$ into hadrons. We resum the large logarithms in the Laplace-conjugated space and compare our results with those obtained with the analytic resummation formalism in the physical ($T$) space. We find that the differences in the spectra obtained with the two different formalisms are sizable. Non-perturbative corrections have been included through an analytic hadronization model depending on two free parameters. Finally, we present a comparison of our spectra with experimental data at the $Z$-boson mass ($m_Z$) energy, which enables us to extract the value of the QCD coupling ${\alpha }_S(m_Z^2)=0.1181\pm 0.0018$ fully consistent with the world average.

    hep-phPRL(2025)·17 citations
14. 14*

    Light quark contributions to Higgs decays

    A. I. Hernández-Juárez🇲🇽 · R. Gaitán🇲🇽 · R. Martinez🇨🇴

    The literature establishes that the light fermions contributions to the decays $H\to Z\gamma$ and $H\to \gamma \gamma$ are negligible since their coupling with the Higgs is proportional to $m_f$. In the present letter, we show that although such a conclusion is true for leptons, the light quark contributions are zero when we consider their non-perturbative effects.

    hep-ph1 citation
15. 15*

    Summing large Pomeron loops in the saturation region: dipole-nucleus collision beyond nonlinear equations

    Eugene Levin (Tel Aviv U.)🇮🇱

    In this paper we found the dipole-nucleus scattering amplitude at high energies by summing large Pomeron loops. It turns out that the energy dependence of this amplitude is the same as for dipole-dipole scattering. It means that the Balitsky-Kovchegov (BK) equation, which has been derived to describe this scattering, can be trusted only in the limited range of energies: $z\le \sqrt{2\kappa C}{A}^{1/6}$

    hep-phPRD(2025)·4 citations
16. 16*

    Ponderomotive Effects of Ultralight Dark Matter

    Kevin Zhou🇺🇸

    I exhibit a new class of quadratic effects of ultralight dark matter. Axions, dark photons, and dilatons can exert rapidly oscillating forces, torques, and mass shifts on Standard Model particles. These effects average to zero at first order, but shift particle properties at second order, in analogy to the ponderomotive force in optics. Remarkably, these effects scale with the square of the amplitude of the dark matter field, even when the field's direct physical effects depend only on its derivatives. I calculate the resulting observables in electron $g_e-2$ experiments using classical mechanics, recovering results previously derived using field theory. When considered properly, these particular experiments do not beat astrophysical bounds, but other precision experiments may have interesting sensitivity.

    hep-phJHEP(2025)·8 citations
17. 17*

    ALP Production from Abelian Gauge Bosons: Beyond Hard Thermal Loops

    Mathias Becker🇮🇹 · Julia Harz🇩🇪 · Enrico Morgante🇮🇹 · Cristina Puchades-Ibáñez🇩🇪 · Pedro Schwaller🇩🇪

    Previous computations of feebly interacting particle production have encountered issues with unphysical (negative) interaction rates at soft momenta. We address this problem by studying the production of Axion-Like Particles (ALPs) coupled to $U(1)$-gauge fields, employing the full form of 1PI-resummed gauge boson propagators. This approach avoids the need for matching or subtraction procedures, ensuring physically consistent results. We find that the ALP production rate remains positive across all momentum scales and identify the dominant production mechanisms. At soft ALP momenta ($p\lesssim g^{2}T$), interactions involving two spacelike gauge bosons dominate the production rate, surpassing other channels by an order of magnitude. In particular, using the full gauge boson propagator suggests that at even softer momenta ($p\lesssim g^{4}T$), production involving two timelike gauge bosons becomes significant, potentially exceeding other contributions by another order of magnitude. Using these insights, we update the thermal ALP abundance and refine the estimate of the average ALP momentum, providing important input for structure formation constraints on ALP dark matter in the keV mass range.

    hep-phJHEP(2025)·12 citations
18. 18*

    Cooling the Shock: New Supernova Constraints on Dark Photons

    Andrea Caputo🇨🇭 · Hans-Thomas Janka🇩🇪 · Georg Raffelt🇩🇪 · Seokhoon Yun🇰🇷

    During the accretion phase of a core-collapse supernova (SN), dark-photon (DP) cooling can be largest in the gain layer below the stalled shock wave. In this way, it could counter-act the usual shock rejuvenation by neutrino energy deposition and thus prevent the explosion. This peculiar energy-loss profile derives from the resonant nature of DP production. The largest cooling and thus strongest constraints obtain for DP masses of 0.1-0.4 MeV, a range corresponding to the photon plasma mass in the gain region. Electron-capture SNe, once observationally unambiguously identified, could provide strong bounds even down to nearly 0.01 MeV. For a coupling strength so small that neutrino-driven explosions are expected to survive, the DP cooling of the core is too small to modify the neutrino signal, i.e., our new argument supersedes the traditional SN1987A cooling bound.

    hep-phastro-ph.HEPRL(2025)·16 citations
19. 19*

    Direct Dark Matter searches with Metal Halide Perovskites

    Davide Baiocco🇮🇹 · Damiano Marian🇮🇹 · Giulio Marino🇮🇹 · Paolo Panci🇮🇹 · Marco Polini🇮🇹 · Alessandro Tredicucci🇮🇹

    Polar materials with optical phonons in the meV range are excellent candidates for both dark matter direct detection (via dark photon-mediated scattering) and light dark matter absorption. In this study, we propose, for the first time, the metal halide perovskites MAPbI${}_3$, MAPbCl${}_3$, and CsPbI${}_3$ for these purposes. Our findings reveal that CsPbI${}_3$ is the best material, significantly improving exclusion limits compared to other polar materials. For scattering, CsPbI${}_3$ can probe dark matter masses down to the keV range. For absorption, it enhances sensitivity to detect dark photon masses below $\sim 10\mathrm{meV}$. The only material which has so far been investigated and that could provide competitive bounds is CsI, which, however, is challenging to grow in kilogram-scale sizes due to its considerably lower stability compared to CsPbI${}_3$. Moreover, CsI is isotropic while the anisotropic structure of CsPbI${}_3$ enables daily modulation analysis, showing that a significant percentage of daily modulation exceeding 1% is achievable for dark matter masses below $40\mathrm{keV}$.

    hep-phastro-ph.COcond-mat.mtrl-scihep-exPRD(2025)·3 citations
20. 20*

    Transverse force distributions in the proton from lattice QCD

    K. U. Can🇦🇺 · J. A. Crawford🇦🇺 · R. Horsley🇬🇧 · P. E. L. Rakow🇬🇧 · G. Schierholz🇩🇪 · H. Stüben🇩🇪 · R. D. Young🇦🇺 · J. M. Zanotti🇦🇺

    Single-spin asymmetries observed in polarised deep-inelastic scattering are important probes of hadron structure. The Sivers asymmetry provides information about the transverse momentum of the struck quark and can be related to final-state interactions. Understanding these asymmetries at the quark level has been the subject of much interest in QCD phenomenology. In this contribution, we present a lattice QCD calculation of the transverse spatial distribution of a colour-Lorentz force acting on the struck quark in a proton. Our lattice calculations employ $N_f=2+1$ flavours of dynamical fermions at the SU(3) symmetric point across three lattice spacings. We determine a central, spin-independent confining force, as well as spin-dependent force distributions with local forces larger than the QCD string tension. These distributions offer a new, complimentary picture that underlies the Sivers asymmetry in transversely polarised deep-inelastic scattering.

    ↳ hep-lathep-phnucl-thPoS(2025)·0 citations
21. 21*

    Reheating chiral dynamos with spin-0 and massive spin-1 torsions via chiral asymmetry

    Zhi-Fu Gao🇨🇳 · Biao-Peng Li🇨🇳 · L.C. Garcia de Andrade🇧🇷

    Recently, Syderenko et al. (JCAP, 10: 018, 2016) investigated magnetogenesis and chiral asymmetry in the early hot universe. This study explores the impact of minimally coupling a constant torsion in their cosmological model, suggesting new chiral physics. Physically, this means that if torsion is right chiral, the difference between the number of right and left chiralities does not change. Moreover, the decay of chiral asymmetry depends on torsion chirality. We solve the chiral torsionful dynamo equation for magnetic field seeds. Magnetic helical fields are considered important for chiral fermion asymmetry. Even in $(3+1)$ dimensional spacetime, torsion is highly suppressed beyond inflation (Eur Phys J C 82: 291, 2022). However, torsion of $1\mathrm{MeV}$ appears in the early universe. Equations for correlated magnetic field coefficients are solved in terms of torsion. Weak magnetic fields of the order of $10^{-42}$ Gauss are boosted by powerful torsionful dynamo amplification, generating a much stronger magnetic field of the order of $10^{-9}$ Gauss in the present universe. A galactic magnetic field of $10^{-6}$ Gauss in the present universe, with torsion of $10^{-15}$ Gauss, leads us to a galactic dynamo seed of $10^{-9}$ Gauss. We also discuss reheating dynamo regeneration of decaying cosmic magnetic fields during the hadronization era. The relation between the reheating contribution to e-folds and the connection between CMF and temperature squared allows us to obtain dynamo amplification in terms of N-folds of inflation. The main innovation of this work is the exploration of constant torsion in a cosmological model, revealing new chiral physics. This study offers a new perspective on the origin and evolution of magnetic fields in the early universe.

    ↳ astro-ph.COgr-qchep-ph0 citations
22. 22*

    Effect of a repulsive three-body interaction on the $D{D}^{(\ast )}K$ molecule

    Ya-Wen Pan🇨🇳 · Jun-Xu Lu🇨🇳 · Emiko Hiyama🇯🇵 · Li-Sheng Geng🇨🇳 · Atsushi Hosaka🇯🇵

    The hadronic molecular picture of the observed exotic states has inspired numerous investigations into few-body systems. Recently, the lattice effective field theory studied the effect of a three-body interaction on the binding energy of the $D{D}^{\ast }K$ system, revealing an intriguing phenomenon in the binding energy. This work uses the Gaussian expansion method to explore the underlying physics. Our results show that as the repulsive three-body interaction strengthens, the spatial size of the $D{D}^{(\ast )}K$ bound state gradually increases. Further enhancement of the three-body interaction causes the $D{D}^{(\ast )}K$ three-body bound state to break into a $D^{(\ast )}K$ two-body bound state, accompanied by a distant $D$ meson. The identical nature of the two $D$ mesons leads to the fact that the $DDK$ system consistently resembles an isosceles triangle-shaped spatial configuration.

    ↳ nucl-thhep-lathep-phPRD(2025)·6 citations
23. 23*

    Resolving the Problem of Multiple Control Parameters in Optimized Borel-Type Summation

    V.I. Yukalov🇷🇺 · S. Gluzman🇨🇦

    One of the most often used methods of summing divergent series in physics is the Borel-type summation with control parameters improving convergence, which are defined by some optimization conditions. The well known annoying problem in this procedure is the occurrence of multiple solutions for control parameters. We suggest a method for resolving this problem, based on the minimization of cost functional. Control parameters can be introduced by employing the Borel-Leroy or Mittag-Leffler transforms. Also, two novel transformations are proposed using fractional integrals and fractional derivatives. New cost functionals are advanced, based on lasso and ridge selection criteria, and their performance is studied for a number of models. The developed method is shown to provide good accuracy for the calculated quantities.

    ↳ math-phcond-mat.stat-mechhep-phmath.MPJ.Math.Chem.(2025)·3 citations
24. 24*

    Gradient flow of the Weinberg operator

    Tanmoy Bhattacharya🇺🇸 · Shohini Bhattacharya🇺🇸 · Vincenzo Cirigliano🇺🇸 · Rajan Gupta🇺🇸 · Emanuele Mereghetti🇺🇸 · Sungwoo Park🇺🇸 · Jun-Sik Yoo🇺🇸 · Boram Yoon🇺🇸

    We present preliminary results on the susceptibilities involving the CP-violating (CPV) Weinberg three-gluon operator and the topological $\Theta$ term using the gradient flow scheme, and study their continuum and chiral extrapolations. These are used to provide an estimate of the $\Theta$ induced by the Weinberg operator in theories with the Peccei-Quinn (PQ) mechanism. Combined with the calculations of the matrix elements (MEs) of quark-bilinears between nucleon states, such calculations will enable estimates of the electric dipole moments (EDMs) and CPV pion-nucleon couplings due to the Weinberg operator, thereby providing robust constraints on beyond the standard model (BSM) physics.

    ↳ hep-lathep-phPoS(2025)·4 citations
25. 25*

    Hadron structure via Generalized Parton Distributions

    Shohini Bhattacharya🇺🇸

    Recent advancements have made it possible to approximate light-cone correlation functions in lattice QCD by computing their Euclidean counterparts. In these proceedings, we review key developments in this approach and explore their direct implications for Generalized Parton Distributions (GPDs). Furthermore, we emphasize the pivotal role of GPDs in uncovering the internal structure of hadrons and beyond.

    ↳ hep-lathep-phPoS(2025)·3 citations
26. 26*

    Fractional vorticity, Bogomol'nyi-Prasad-Sommerfield systems and complex structures for the (generalized) spinor Gross-Pitaevskii equations

    Fabrizio Canfora🇨🇱 · Pablo Pais🇨🇱

    The (generalized) Gross-Pitaevskii equation (GPE) for a complex scalar field in two spatial dimensions is analyzed. It is shown that there is an infinite family of self-interaction potentials which admit Bogomol'nyi-Prasad-Sommerfield (BPS) bounds together with the corresponding first-order BPS systems. For each member of this family, the solutions of the first-order BPS systems are automatically solutions of the corresponding second-order generalized GPE. The simplest topologically non-trivial solutions of these first-order BPS systems describe configurations with quantized fractional vorticity. The corresponding fraction is related to the degree of non-linearity. The case in which the self-interaction potential is of order six (namely $|\Psi {|}^6$, which is a relevant theory both in relativistic quantum field theories in $(2+1)$ dimensions in connection with the quantum Hall effect as well as in the theory of the supersolids) is analyzed in detail. Such formalism can also be extended to the case of quantum mixtures with multi-component GPEs. The relationship between these techniques and supersymmetry will be discussed. In particular, despite several common features, we will show that there are multi-component GPEs that are not supersymmetric (at least, not in the standard sense) and possess a BPS system of the above type.

    ↳ cond-mat.quant-gashep-phhep-thnucl-thNPB(2025)·8 citations
27. 27*

    The nucleon structure from an AdS/QCD model in the Veneziano limit

    Jiali Deng (CCNU)🇨🇳 · Defu Hou (CCNU)🇨🇳

    We employ the VQCD model, a holographic approach that dynamically simulates essential QCD characteristics, including linear mass spectra, confinement, asymptotic freedom, and magnetic charge screening, while incorporating quark flavor effects. Using this model, we first calculate the proton mass spectrum and the wave function, incorporating anomalous dimensions to refine our results. Next, we compute the proton structure functions across a range of Bjorken $x$ values using consistent parameters. Furthermore, we derive the proton electromagnetic form factor by solving the electromagnetic field's motion equation, accounting for background effects, and demonstrate qualitative consistency with results from free electromagnetic fields coupled to fermions. Finally, we calculate the gravitational form factors by introducing an effective graviton mass $m$ arising from chiral symmetry breaking and the proton energy-momentum tensor. Our calculations yield results that are in excellent agreement with experimental data and lattice QCD computations, validating the VQCD model as a robust tool for studying proton properties.

    ↳ nucl-thhep-phPRD(2025)·13 citations
28. 28*

    Kaon Modification in Pion Medium

    Yu. B. Ivanov🇷🇺

    Kaon properties in thermal pion-nucleon medium are studied. The dense pion-nucleon medium is produced in high-energy heavy-ion collisions. The consideration is based on the chiral nucleon-kaon-pion Lagrangian. It is found that the pion medium does not produce a substantive contribution but enhances the effect of the baryon matter. Numerical estimate shows that this enhancement factor induced by the pion medium does not exceed 5% at the freeze-out stage of heavy-ion collisions, i.e. it is small. However, the impact of this enhancement can be higher in actual nuclear collisions because the effect of the in-medium (anti)kaon modification is accumulated during the (anti)kaon evolution before the freeze-out when the pion density is higher.

    ↳ nucl-thhep-phPhys.Part.Nucl.Lett.(2025)·0 citations
29. 29*

    Can Q-balls describe cosmological and galactic dark matter?

    Susobhan Mandal🇮🇳 · S. Shankaranarayanan (IIT Bombay)🇮🇳

    The Cold Dark Matter (CDM) hypothesis accurately predicts large-scale structure formation and fits the Cosmic Microwave Background temperature fluctuations (CMB). However, observations of the inner regions of dark matter halos and dwarf galaxy satellites have consistently posed challenges to CDM. On the other hand, the Modified Newtonian Dynamics (MOND) hypothesis can explain galactic phenomena but fails to account for the complex shape of the CMB and matter power spectra. CDM and MOND are effective in nearly mutually exclusive regimes, prompting the question: Is there a physical mechanism where CDM and MOND share a common origin? Q-balls, which are localized, non-topological solitons, can be a bridge between the two hypotheses. Q-balls formed in the early Universe can mimic CDM at cosmological scales. Interestingly, Q-balls can exhibit MOND-like behavior in the late Universe at galactic scales, providing a unified framework. Specifically, we demonstrate that millicharged composite Q-balls formed from complex scalar fields, decoupled from the background radiation, can naturally arise during the radiation-dominated epoch. From the matter-radiation equality, we also obtain the mass of Q-balls to be $1eV$, which are much smaller than the electron mass. Using the constraints from the invisible decay mode of ortho-positronium, we obtain $Q<3.4\times 10^{-5}$. We also establish an upper bound on the number density of Q-balls, which depends on the charge of the Q-ball and the small initial charge asymmetry. Furthermore, we demonstrate that the MOND naturally emerges at the galactic scale within the framework of our Q-ball model.

    ↳ hep-thastro-ph.COgr-qchep-phEPJC(2025)·1 citation
30. 30*

    Antipodal self-duality of square fishnet graphs

    Lance J. Dixon🇺🇸 · Claude Duhr🇩🇪

    In strongly-deformed planar $\mathcal{N}=4$ super-Yang-Mills theory, or fishnet theory, a point-split single-trace correlation function of four dimension-$m$ scalar operators is given by a single Feynman integral, which involves integrating over locations of a $m\times m$ grid of points. We show that for any integer $m$ this square fishnet graph is invariant under the combined action of a kinematic map and the antipode map of the Hopf algebra on multiple polylogarithms, i.e. it possesses an antipodal self-duality.

    ↳ hep-thhep-phPRD(2025)·13 citations
31. 31*

    Dense and magnetized QCD from imaginary chemical potential

    Szabolcs Borsányi🇩🇪 · Bastian Brandt🇩🇪 · Gergely Endrődi🇭🇺 · Jana Guenther🇩🇪 · Marc-André Petri🇩🇪 · Adeilton Dean Marques Valois🇩🇪 · Lukas Varnhorst🇩🇪

    In this work, we computed the equation of state of dense QCD in the presence of background magnetic fields using lattice QCD simulations at imaginary baryon chemical potential. Our simulations include 2+1+1 flavors of stout-smeared staggered fermions with masses at the physical point and a tree-level Symanzik-improved gauge action. Using several expansion schemes, we tuned our simulation parameters such that the equation of state satisfies strangeness neutrality and isospin asymmetry constraints, which are relevant to the phenomenology of heavy-ion collisions. Our results suggest a strong change in the equation of state due to the magnetic field, in particular, around the crossover temperature. A continuum extrapolation of our data is still needed for future applications of our equation of state to heavy-ion-collision phenomenology.

    ↳ hep-lathep-phhep-thPoS(2025)·9 citations
32. 32*

    Out-of-equilibrium Chiral Magnetic Effect via Kubo formulas

    B. B. Brandt🇩🇪 · G. Endrődi🇩🇪 · E. Garnacho-Velasco🇩🇪 · G. Markó🇩🇪 · A. D. M. Valois🇩🇪

    In this proceedings article, we present the first steps towards the determination of the out-of-equilibrium conductivity of the Chiral Magnetic Effect (CME) in the presence of strong interactions. Using linear response theory, we obtain an analytical expression for the spectral function associated with this effect at one-loop in perturbation theory. In addition, we provide a first estimate of the CME conductivity by calculating the associated Euclidean correlator using quenched Wilson fermions and dynamical staggered fermions in physical Quantum Chromodynamics (QCD) simulations. In particular, we focus on the midpoint of the correlator, which can be used as a proxy of the full conductivity. We present results in a wide range of temperatures, showing how this observable is suppressed at low temperatures, while at high temperatures it approaches the perturbation theory prediction.

    ↳ hep-lathep-exhep-phhep-th+1PoS(2025)·10 citations
33. 33*

    Renormalization-group approach to the Kohn-Luttinger superconductivity: Amplification of the pairing gap from ${\ell }^4$ to $\ell$

    Yuki Fujimoto🇯🇵

    We revisit the renormalization group (RG) analysis of the Kohn-Luttinger (KL) mechanism for superconductivity. The KL mechanism leads to superconductivity in a system with a repulsive bare interaction. The key ingredient is the screening effect that renders the induced interaction attractive in channels with nonzero angular momentum $\ell \ne 0$, thereby triggering the Bardeen-Cooper-Schrieffer (BCS) instability. According to the original argument, the resulting gap is exponentially small, with its exponent scaling as $-{\ell }^4$. However, the KL mechanism was originally formulated within perturbation theory, where the series is known to converge poorly in certain cases -- most notably, for the p-wave paring gap induced by a repulsive s-wave contact interaction. This poor convergence may be attributed to a divergent integrand in a specific class of diagrams containing both the BCS logarithm and the Kohn anomaly, suggesting that one must resum the Kohn anomaly contributions separately from the BCS logarithm. In this work, we incorporate the Kohn anomaly contribution into the beta function of the RG equation governing the BCS instability near the Fermi surface. Our solution shows that the KL gap exponent is then proportional to $-\ell$, indicating a significant enhancement of the KL mechanism beyond the previously known result. To illustrate this, we study the spin-triplet p-wave pairing gap arising from a repulsive s-wave contact interaction and compare our RG-based results with those obtained from the Bethe-Salpeter equation in perturbation theory.

    ↳ cond-mat.supr-conhep-phnucl-thPRB(2025)·3 citations
34. 34*

    Lattice techniques to investigate the strong $CP$ problem: lessons from a toy model

    David Albandea🇪🇸 · Guilherme Catumba🇪🇸 · Alberto Ramos🇪🇸

    Recent studies have claimed that the strong $CP$ problem does not occur in QCD, proposing a new order of limits in volume and topological sectors when studying observables on the lattice. We study the effect of the topological term on a simple quantum mechanical rotor that allows a lattice description. We particularly focus on recent proposals to face the challenging problems that this study poses in lattice QCD and that are also present in the quantum rotor, such as topology freezing and the sign problem.

    ↳ hep-lathep-phPoS(2025)·0 citations
35. 35*

    $U(1{)}_A$ Breaking in Hot QCD in the Chiral Limit

    Tamas G. Kovacs (Eotvos U. and Debrecen, Inst. Nucl. Res.)🇭🇺

    We propose a simple instanton-based random matrix model of hot QCD that in the quenched case precisely reproduces the distribution of the lowest lattice overlap Dirac eigenvalues. Even after including dynamical quarks the model can be easily simulated in volumes and for quark masses that will be out of reach for direct lattice simulations in the foreseeable future. Our simulations show that quantities connected to the $U(1{)}_A$ and $SU(N_f{)}_A$ chiral symmetry are dominated by eigenvalues in a peak of the spectral density that becomes singular at zero in the thermodynamic limit. This spectral peak turns out to be produced by an ideal instanton gas. By generalizing Banks-Casher type integrals for the singular spectral density, definite predictions can be given for physical quantities that are essential to test chiral symmetry breaking, but presently impossible to compute reliably with direct lattice simulations.

    ↳ hep-lathep-phhep-thPoS(2025)·1 citation
36. 36*

    Strong coupling in (2+1+1)-flavor QCD

    Viljami Leino🇩🇪 · Alexei Bazavov🇺🇸 · Nora Brambilla🇩🇪 · Andreas Kronfeld🇺🇸 · Julian Mayer-Steudte🇩🇪 · Peter Petreczky🇺🇸 · Sebastian Steinbeißer🇩🇪 · Antonio Vairo🇩🇪 · Johannes Heinrich Weber🇩🇪

    The strong coupling ${\alpha }_{\mathrm{s}}$ can be obtained from the static energy as shown in previous lattices studies. For short distances, the static energy can be calculated both on the lattice with the use of Wilson line correlators, and with the perturbation theory up to three loop accuracy with leading ultrasoft log resummation. Comparing the perturbative expression and lattice data allows for precise determination of ${\alpha }_{\mathrm{s}}(m_Z)$. We will present preliminary results for the determination of ${\alpha }_{\mathrm{s}}(M_Z)$ in (2+1+1)-flavor QCD using the configurations made availableby the MILC-collaboration with smallest lattice spacing reaching 0.0321fm.

    ↳ hep-lathep-phPoS(2025)·3 citations
37. 37*

    Quasinormal modes of nonthermal fixed points

    Matisse De Lescluze🇧🇪 · Michal P. Heller🇧🇪

    Quasinormal modes play a prominent role in relaxation of diverse physical systems to equilibria, ranging from astrophysical black holes to tiny droplets of quark-gluon plasma at RHIC and LHC accelerators. We propose that a novel kind of quasinormal modes govern the direct approach to self-similar time evolution of nonthermal fixed points, whose relevance ranges from high energy physics to cold atom gases. We utilize black hole perturbation theory techniques to compute the spectrum of these far from equilibrium quasinormal modes for a kinetic theory with a Focker-Planck collision kernel in isotropic and homogeneous states. Our conclusion is that quasinormal modes of nonthermal fixed points give rise to a tower of progressively more decaying power-law contributions. A byproduct of our analysis is a precise determination and improved understanding of the distribution function characterizing nonthermal fixed points.

    ↳ hep-thcond-mat.quant-gasgr-qchep-ph+1PRL(2025)·12 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.