Fri·Jan 31, 2025Friday·January 31, 2025

1. 01*

   Anisotropy in Magnetized Quark Matter in the Chiral Limit

   S. A. Ferraris🇦🇷 · J. P. Carlomagno🇦🇷 · G. A. Contrera🇦🇷 · A. G. Grunfeld🇦🇷

   We investigate the behavior of cold quark matter under strong magnetic fields in the frame of a nonlocal NJL model in the chiral limit. Our analysis focuses on deconfinement, chiral symmetry restoration, and the anisotropy in pressure induced by the external magnetic field. For $eB\lesssim 0.07{\text{GeV}}^2$, the critical chemical potential remains largely insensitive to the magnetic field, whereas at higher field strengths, transitions to chirally restored phases occur at progressively lower chemical potentials. The parallel and perpendicular pressures, respect to the magnetic field, exhibit distinct behaviors, reflecting the anisotropic nature of the system. Oscillations in the quark number density, driven by the de Haas van Alphen effect, reflect the quantized behavior of quarks in a magnetic field. Similarly, the magnetization displays oscillatory behavior, driven by the sequential filling of Landau levels. At lower external magnetic field strengths, contributions from orbital angular momentum and the population of higher Landau levels further modulate these oscillations. These results provide deeper insights into the thermodynamic and magnetic properties of quark matter under strong magnetic fields, with implications for astrophysical studies.

   hep-phAstron.Nachr.(2025)·1 citation
2. 02*

   Spectral-statistics properties of the experimental and theoretical light baryon and meson spectra

   L. Muñoz🇪🇸 · A. Relaño🇪🇸

   We compare the statistical fluctuation properties of the baryon and meson experimental mass spectra with those obtained from theoretical models (quark models and lattice QCD). We find that for the experimental spectra the statistical properties are close to those predicted by Random Matrix Theory for chaotic systems, while for the theoretical ones they are in general closer to those predicted for integrable systems and safely incompatible with those of chaotic systems. We stress the importance of the agreement of the fluctuation properties between experiment and theoretical models, as they determine the dynamical regime and the complexity of the real interactions. We emphasize the new statistical method we use, adapted for properly analyzing the fluctuation properties for very short spectral sequences.

   hep-phnlin.CDnucl-thPRC(2015)·1 citation
3. 03*

   Distribution amplitudes of heavy-light pseudo-scalar and vector mesons from Dyson-Schwinger equations framework

   Yin-Zhen Xu🇪🇸

   We report the first Dyson-Schwinger equation predictions for the leading-twist distribution amplitudes of the $B^{\ast }$, $B_s^{\ast }$, and $B_c^{\ast }$ mesons, and extend the investigation to a broader set of heavy-light pseudo-scalar/vector mesons. Numerical analysis shows that, in flavor-asymmetric systems, the distribution amplitude is skewed toward the heavier quark, with the position of the maximum $\sim M_E^f/(M_E^f+M_E^g)$, where $M_E$ is the Euclidean constituent quark mass and $f$, $g$ denote the quark flavors. Spin effects are found to be subleading compared to the influence of valence-quark composition, and lead to heavier quarks carrying more light-front momentum in vector mesons than in their pseudo-scalar counterparts. Our results can be compared with both experimental and theoretical outcomes in the future.

   hep-phPRD(2025)·10 citations
4. 04*

   Spin-dependent dark matter scattering in quasi-two-dimensional magnets

   Giacomo Marocco🇺🇸 · John Wheater🇬🇧

   We study the prospects of detecting dark matter coupled to the spin of the electron, such that it may scatter and excite magnons - collective excitations of electronic spins. We show that materials exhibiting long-range magnetic order where the spins are coupled only along a plane may act as directional dark matter detectors. These quasi-2D materials possess anisotropic dispersion relations and structure functions which induce a sidereal modulation in the excitation rate. We calculate the expected signal rate for some candidate (anti)ferromagnets, demonstrating a possible route to the direct detection of spin-dependent dark matter in the keV to MeV mass range.

   hep-phPRD(2025)·12 citations
5. 05*

   Baryon Construction with ${\eta }^{\prime }$ Meson Field

   Fan Lin🇨🇳 · Yong-Liang Ma🇨🇳

   In the low-energy regime, baryons with $N_f\ge 2$ have long been constructed as skyrmions or through bag models, but such constructions for $N_f=1$ are hindered by the trivial topological structure of the meson field. Recent proposals suggest that one-flavor baryons can instead be interpreted as quantum Hall droplets on the ${\eta }^{\prime }$ domain wall, providing a potential link to quark--hadron continuity at high density. In retrospect, the qualitative or semi-qualitative construction of one-flavor baryons on the ${\eta }^{\prime }$ domain wall reveals that these baryons can be described as quantum Hall droplets, resembling topological solitons akin to skyrmions. Using an effective theory on the ${\eta }^{\prime }$ domain wall, which is conjectured to be the Chern--Simons--Higgs theory, it is discussed that its vortex solution with unit baryon numbers naturally has a spin of $N_c/2$, and thus can be interpreted as a baryon or multi-baryon structure. The particle--vortex duality suggests that quarks carry a fractional topological charge of $1/N_c$ and obey fractional statistics. In terms of chiral bag models, confinement can be attributed to the monopoles confined within the bag, and the vector meson fields on the bag surface are essential for ensuring the correct baryon number in the chiral bag framework, thereby providing deeper insights into baryons as non-trivial topological structures of the meson field. In this paper, we review the progress in this development, with a special focus on the ${\eta }^{\prime }$ domain wall dynamics. Naive extensions to $N_f\ge 2$ are also discussed.

   hep-phhep-thnucl-thSymmetry(2025)·1 citation
6. 06*

   Spacetime profile of electromagnetic fields in intermediate-energy heavy-ion collisions

   Hidetoshi Taya🇯🇵

   I numerically estimate the spacetime profile of the electromagnetic fields produced in intermediate-energy heavy-ion collisions at $\text{sqsNN}=2.4\text{mathchar}‘-7.7\mathrm{GeV}$ for a wide range of impact parameters $b=0\text{mathchar}‘-9\mathrm{fm}$, using a hadronic cascade model, JAM (Jet AA Microscopic transport model). I demonstrate that (1) the produced electromagnetic fields are as strong as $eE,eB=\mathcal{O}((50\mathrm{MeV}{)}^2)$; (2) that the produced fields extend in spacetime about $V_4=\mathcal{O}((10\mathrm{fm}{)}^4)$; (3) that the magnetic field dominates around the collision point, while the other broad regions of spacetime are dominated by the electric field; and (4) that a topological electromagnetic-field configuration such that $\mathbf{E}\cdot \mathbf{B}\ne 0$ is realized.

   hep-phnucl-thPRC(2025)·4 citations
7. 07*

   Fits of ${\alpha }_s$ from event-shapes in the three-jet region: extension to all energies

   Paolo Nason🇮🇹 · Giulia Zanderighi🇩🇪

   This work is an extension of a previous publication [1] where we fitted the strong coupling ${\alpha }_s$ together with the non-perturbative parameter ${\alpha }_0$ from event-shape and jet-shape distributions using power corrections computed in the three-jet region. In ref. [1] only ALEPH data at the $Z$-pole were used in the fit. Here, instead, we include a large data sample from various $e^{+}{e}^{-}$ experiments at energies ranging from 22 to 207 GeV and revisited the treatment of theoretical uncertainties. We find that the inclusion of different energies, while not changing the central fit result considerably, helps to disentangle the dependence of perturbative and non-perturbative corrections. Our best fit result is ${\alpha }_s(M_Z)=0.1181(+0.0002-0.0005)(+0.0018-0.0021)$, where the first error includes experimental uncertianties and the second one includes uncertainties associated with scale variation, mass effects, fit limits, non-perturbative schemes and non-perturbative uncertainties.

   hep-phJHEP(2025)·20 citations
8. 08*

   Permuted Charged Lepton Correction in the Framework of Dirac Seesaw

   Sagar Tirtha Goswami🇮🇳 · Subhankar Roy🇮🇳

   A Dirac neutrino mass model is proposed, based on an extended group structure of $SU(2{)}_L\otimes U(1{)}_Y\otimes A_4\otimes Z_3\otimes Z_{10}$ with the Type-I seesaw mechanism. This work explores the impact of parametrization and permutation in the charged lepton diagonalizing matrix, driven by free parameters in the charged lepton sector, on the predictions of observable parameters. Some interesting consequences on the neutrino mass hierarchies, mixing angles and the Dirac CP phase are observed. The framework also finds application in the study of charged lepton flavour violation and dark matter.

   hep-phNPB(2026)·6 citations
9. 09*

   Non-standard cosmological scenarios, Sommerfeld enhancement and asymmetric dark matter

   Reyima Rashidin🇨🇳 · Fangyu Liu🇨🇳 · Hoernisa Iminniyaz🇨🇳

   We discuss the relic density of asymmetric dark matter with long-range interactions in non-standard cosmological scenarios where the extra cosmic energy is introduced. The Hubble expansion rate is modified in non-standard cosmological models, which affects the relic density of dark matter. If the mass of the dark exchanged gauge boson is less than the mass of dark matter particles multiplied by the dark fine-structure constant, the wave function of the incoming particles of dark matter annihilation would be distorted away from the free plane-wave approximation, yielding the significant enhancements to annihilation cross sections, known as Sommerfeld enhancement. Sommerfeld enhancement results the asymmetric dark matter relic density under abundant, while the enhanced cosmic expansion rate increases the relic density of asymmetric dark matter by letting the decoupling from the thermal equilibrium occurs earlier. However, the mixed effect of modified cosmic expansion and the Sommerfeld enhancement on asymmetric dark matter density evolution becomes quite complicated, due to their opposing affects on relic density and contrary strength developments as the temperature fell. We investigated the mixed effects on asymmetric dark matter freeze-out process and current relic abundance, which is significantly different from the standard situation. Further, we calculate the constraint relations of the asymmetric dark matter pertubative annihilation cross section and dark coupling constant with the mass of asymmetric dark matter, the asymmetry factor with the dark coupling constant, when the relic density of asymmetric dark matter falled in the observed region. The upper bounds on the mass of asymmetric dark matter for s-wave and p-wave annihilations are also derived.

   hep-phNPB(2026)·1 citation
10. 10*

    A general upper bound on the light dark matter scattering rate in materials

    Riccardo Catena🇸🇪 · Michał Iglicki🇸🇪

    Combining an effective theory description of spin-1/2 dark matter (DM)-electron interactions in materials with linear response theory provides a powerful framework to model the scattering of DM, including in-medium effects, in detectors used for direct searches. Within this framework, we show that the rate of DM-induced electronic transitions in detector materials admits a theoretical upper bound under general assumptions on the underlying DM-electron coupling. In particular, our theoretical upper bound applies to models where DM couples to the electron density as well as the spin, paramagnetic and Rashba currents in materials, and arises from the Kramers-Kronig relations that constrain the analytic properties of the scattering rate. We evaluate our maximum rate formula numerically for Ar, Xe, Ge, and Si targets and find that Ge and Si detectors are closer to saturate this theoretical upper bound, but still far from saturation when DM couples to densities or currents which are different from the electron density. This motivates the exploration of a different class of materials to effectively probe such coupling forms.

    hep-phastro-ph.COJCAP(2025)·4 citations
11. 11*

    Factorisation schemes for proton PDFs

    Stéphane Delorme🇵🇱 · Aleksander Kusina🇵🇱 · Andrzej Siódmok🇵🇱 · James Whitehead🇵🇱

    Beyond leading-order, perturbative QCD requires a choice of factorisation scheme to define the parton distribution functions (PDFs) and hard-process cross-section. The modified minimal-subtraction ($\overline{\mathrm{MS}}$) scheme has long been adopted as the default choice due to its simplicity. Alternative schemes have been proposed with specific purposes, including, recently, PDF positivity and NLO parton-shower matching. In this paper we assemble these schemes in a common notation for the first time. We perform a detailed comparison of their features, both analytically and numerically, and estimate the resulting factorisation-scheme uncertainty for LHC phenomenology.

    hep-phhep-thEPJC(2025)·10 citations
12. 12*

    't Hooft model in the temporal gauge

    Paul Hoyer🇫🇮

    I consider QCD${}_2$ in the $N_c\to \infty$ limit at fixed $g^2{N}_c$. The derivation starts from equal-time $q\bar{q}$ bound states in coordinate space and temporal ($A^0=0$) gauge, avoiding the use of quark and gluon propagators. The wave function is given analytically by a ${}_1{F}_1$ function with an explicit frame dependence. In the infinite momentum frame the Fourier transformed wave function satisfies the 't~Hooft equation, however with contributions also from quarks with negative kinetic energy. Such contributions are present also in the rest frame, and do not vanish under boosts.

    hep-phnucl-thPRD(2025)·3 citations
13. 13*

    Optimizers for Stabilizing Likelihood-free Inference

    G. Bruno De Luca🇺🇸 · Benjamin Nachman🇺🇸 · Eva Silverstein🇺🇸 · Henry Zheng🇺🇸

    A growing number of applications in particle physics and beyond use neural networks as unbinned likelihood ratio estimators applied to real or simulated data. Precision requirements on the inference tasks demand a high-level of stability from these networks, which are affected by the stochastic nature of training. We show how physics concepts can be used to stabilize network training through a physics-inspired optimizer. In particular, the Energy Conserving Descent (ECD) optimization framework uses classical Hamiltonian dynamics on the space of network parameters to reduce the dependence on the initial conditions while also stabilizing the result near the minimum of the loss function. We develop a version of this optimizer known as $EC{D}_{q=1}$, which has few free hyperparameters with limited ranges guided by physical reasoning. We apply $EC{D}_{q=1}$ to representative likelihood-ratio estimation tasks in particle physics and find that it out-performs the widely-used Adam optimizer. We expect that ECD will be a useful tool for wide array of data-limited problems, where it is computationally expensive to exhaustively optimize hyperparameters and mitigate fluctuations with ensembling.

    hep-phhep-thPRD(2025)·8 citations
14. 14*

    Unitarity triangle angles explained: a predictive new quark mass matrix texture

    P. F. Harrison🇬🇧 · W. G. Scott🇬🇧

    We propose a novel quark mass matrix texture-pair with five free parameters, which fits the four quark mass ratios $m_s/m_b$, $m_d/m_b$, $m_c/m_t$, $m_u/m_t$, and the four CKM quark mixing observables. The matrices each have one texture zero, but the main innovation here is a ``geometric'' ansatz exploiting a pair of small complex expansion parameters, based on the geometry of the Unitarity Triangle. The fit to the observables is in good agreement with current experimental values renormalised to $\sim 10^4$ TeV, and offers decisive tests against future high-precision measurements of the unitarity triangle angles at the weak scale. We identify two novel symmetries of these mass matrices which explain the phenomenologically-successful relations $\alpha \equiv {\varphi }_2\simeq \frac{\pi }{2}$ and $\beta \equiv {\varphi }_1\simeq \frac{\pi }{8}$.

    hep-phJHEP(2025)·6 citations
15. 15*

    Reactor antineutrinos CE$\nu$NS on germanium: CONUS+ and TEXONO as a new gateway to SM and BSM physics

    M. Atzori Corona🇮🇹 · M. Cadeddu🇮🇹 · N. Cargioli🇮🇹 · F. Dordei🇮🇹 · C. Giunti🇮🇹

    Coherent elastic neutrino-nucleus scattering (CE$\nu$NS) is a key process for probing Standard Model and beyond the Standard Model (BSM) properties. Following its first detection by the COHERENT Collaboration, recent reactor-based experiments provide a unique opportunity to refine our current understanding. In particular, the high-precision data from CONUS+, combined with the strong bounds from TEXONO, not only validate the CE$\nu$NS process at low energies but also provide improved constraints on the weak mixing angle, neutrino electromagnetic properties (including the charge radius, millicharge, and magnetic moment), and nonstandard interactions and light mediators. We also examine the role of elastic neutrino-electron scattering, which gains significance in certain BSM scenarios and allows us to obtain the best limit for the millicharge of the electron neutrinos. By combining reactor and higher-energy spallation neutron source measurements, this work strengthens CE$\nu$NS as a precision tool for testing the Standard Model and beyond.

    hep-phhep-exPRD(2025)·30 citations
16. 16*

    CGAN-Based Framework for Meson Mass and Width Prediction

    S. Rostami🇮🇷 · M. Malekhosseini🇮🇷 · M. Rahavi Ezabadi🇮🇷 · K. Azizi🇮🇷

    Mesons play a crucial role in understanding the strong interaction in the framework of quantum chromodynamics (QCD). However, the mass and decay width of several ordinary and exotic mesons remain experimentally undetermined. In this work, we propose a novel application of advanced machine learning techniques to deal with this challenge. Due to the limited available meson datasets, traditional data-driven methods are norm To overcome this, we employ a Conditional Generative Adversarial Network (CGAN) to generate synthetic meson data based on known physical parameters. This not only augments the dataset but also retain the underlying physics of the original mesons data. With the extended dataset, we train multiple copies of CGAN and apply a bagging technique to predict uncertainties, improving the robustness and reliability of the predictions. As our findings indicate, the CGAN models are capable of well describing meson properties and their structure relations, offering a potent novel instrument for hadron spectroscopy. This calculation opens a promising future for data-driven hadron physics studies.

    hep-phhep-exhep-latNPB(2025)·2 citations
17. 17*

    Searching for the Flavon in the diphoton channel at future super hadron colliders

    M. A. Arroyo-Ureña (Facultad de Ciencias Físico-Matemáticas, Benemérita Universidad Autónoma de Puebla)🇲🇽 · Diego Carreño (Facultad de Ciencias Físico-Matemáticas, Benemérita Universidad Autónoma de Puebla)🇲🇽 · T.A. Valencia-Pérez (Instituto de Física, Universidad Nacional Autónoma de México)🇲🇽

    We study the production of a CP-even flavon $H_F$ in proton-proton collisions and the prospects for its detection via the diphoton channel at future super hadron colliders, i.e., $pp\to H_F\to \gamma \gamma$. The theoretical framework adopted is a model that invokes the Froggatt-Nielsen mechanism with an Abelian flavor symmetry, which includes a Higgs doublet and a complex singlet. We confront the free parameters of the model against theoretical and experimental constraints to find the allowed parameter space, which is then used to evaluate the production cross section of the flavon and the branching ratio of its decay into two photons. We find promising results based on specific benchmark points, achieving signal significances at the level of 5$\sigma$ for flavon masses in the interval $200\lesssim M_{H_F}\lesssim 450$ and integrated luminosities in the range $5-12$ ab${}^{-1}$ at the future High-Energy LHC. On the other hand, the Future hadron-hadron Circular Collider could probe masses up to 1 TeV if it reaches an integrated luminosity of at least 2 ab${}^{-1}$.

    hep-phPRD(2025)·1 citation
18. 18*

    Visualizing How the Structure of Large-Radius Jets Shapes Their Wakes

    Arjun Srinivasan Kudinoor🇺🇸 · Daniel Pablos🇪🇸 · Krishna Rajagopal🇺🇸

    The ATLAS collaboration has introduced and implemented a strategy for selecting and analyzing large-radius jets composed of skinny $R=0.2$ subjets in heavy ion collisions at the LHC. We show how measurements of these jets teach us about the resolution length $L_{\mathrm{res}}$ of quark-gluon plasma (QGP) and can teach us how jet substructure shapes the wakes that jets excite in the QGP droplets through which they pass. We use Hybrid Model calculations to reproduce measurements of $R_{AA}$ for large-radius jets in PbPb collisions, and study their dependence on the angle between the two skinny subjets involved in the final reclustering step of an $R=1$ jet. We show how these observables can constrain the value of $L_{\mathrm{res}}$ and demonstrate that the ATLAS data rule out any picture in which an entire parton shower loses energy coherently as if it were a single entity. Determining the degree to which the QGP can resolve partons within a jet is central to the broader program of using jet quenching measurements to probe QGP. We make further use of this setup by analyzing the response of the medium to the passage of large-radius $R=2$ jets containing two skinny subjets in gamma-jet events. We introduce novel jet-shape observables that allow us to visualize the angular shape of the soft hadrons originating from the wakes that wide jets with two skinny subjets excite in a droplet of QGP, as a function of the angular separation between the subjets. We find that even when they are $\sim 0.8-1$ radian apart, a single broad wake is produced. Only when the two subjets are even farther apart is the presence of two sub-wakes revealed. We show that the way in which jet structure shapes jet wakes can be visualized with similar clarity in experiments by using only those hadrons with low $p_T$. These observables thus offer a new and distinctive way of seeing jet wakes in heavy ion collision data.

    hep-phnucl-thJHEP(2026)·11 citations
19. 19*

    The spatial string tension and its effects on screening correlators in a thermal QCD plasma

    Dibyendu Bala🇩🇪 · Olaf Kaczmarek🇩🇪 · Peter Petreczky🇺🇸 · Sayantan Sharma🇮🇳 · Swagatam Tah🇮🇳

    We calculate the spatial Wilson line correlator for 2+1 flavor QCD using highly improved staggered quark discretization for fermions and in quenched QCD for a wide range of temperatures, from the chiral crossover temperature ${\mathrm{T}}_{\mathrm{pc}}\simeq 156$ MeV or the deconfinement temperature $\simeq 300$ MeV respectively, up to $2$ GeV. Extracting the spatial string tension for different lattice cut-offs and by performing a continuum extrapolation of this observable, we show that the soft (magnetic) gluons interact non-perturbatively even at temperatures $\gtrsim 1$ GeV. We provide incriminating evidences to demonstrate that dimensionally reduced effective theories can describe these soft quark and gluon quasi-particles for both quenched and $2+1$ flavor QCD, at temperatures $\mathrm{T}\gtrsim 5{\mathrm{T}}_{\mathrm{pc}}$. We also show for the first time the imprints of the non-perturbative pseudo-potential in the properties of mesonic screening masses for temperatures ranging from $0.8$-$164$ GeV in the quark-gluon plasma.

    ↳ hep-lathep-phnucl-thPRL(2025)·16 citations
20. 20*

    Physics on and off the light cone

    Philip D. Mannheim🇺🇸

    We study light-front physics and conformal symmetry, and their interplay both on and off the light cone. The full symmetry of the light cone is conformal symmetry not just Lorentz symmetry. Spontaneously breaking conformal symmetry gives masses to particles and takes them off the light cone. Canonical quantization specifies equal-time commutators on the light cone. Equal instant-time and equal light-front-time commutators look very different, but can be shown to be equivalent by looking at unequal-time commutators. We discuss the connection of the light-front approach to the infinite momentum frame approach, and show that vacuum graphs are outside this framework. We show that there is a light-front structure to both AdS/CFT and the eikonal approximation. While mass generation involves scale breaking mass scales, we show that such mass scales can arise via dynamical symmetry breaking in the presence of scale invariant interactions at a renormalization group fixed point.

    ↳ hep-thhep-phEur.Phys.J.ST(2026)·0 citations
21. 21*

    Trace dynamics, octonions, and unification: An $E_8\times E_8$ theory of unification

    Tejinder P. Singh🇮🇳

    This is a very brief overview of the ongoing research program of unification known as the octonionic theory. We highlight the quantum foundational origins for the theory, and the seven key ingredients which go into its making.

    ↳ physics.gen-phhep-phJ.Phys.Conf.Ser.(2024)·7 citations
22. 22*

    Fundamental quantum limits for detecting ultrahigh frequency gravitational waves

    Xinyao Guo🇨🇳 · Haixing Miao🇨🇳 · Zhi-Wei Wang🇨🇳 · Huan Yang🇨🇳 · Ye-Ling Zhou🇨🇳

    The ultrahigh-frequency (above 10 kHz) gravitational waves (GW) window provides a unique opportunity to detect primordial GWs, free from astrophysical foregrounds that dominate lower frequencies. A stochastic GW background in this range is generically predicted from cosmological phase transitions and topological defects associated with grand unification and other ultra-high energy theories. We establish a universal quantum limit framework for various detection schemes, setting a fundamental bound on GW detectability. Our analysis reveals that backgrounds in the kHz-MHz range are in principle observable, whereas higher-frequency signals lie below the quantum limit. These results offer theoretical guidance for future detector designs and open new avenues for probing early universe physics.

    ↳ gr-qcastro-ph.IMhep-phhep-thPRD(2026)·10 citations
23. 23*

    Gaussian-process reconstructions and model building of quintom dark energy from latest cosmological observations

    Yuhang Yang🇨🇳 · Qingqing Wang🇨🇳 · Chunyu Li🇨🇳 · Peibo Yuan🇨🇳 · Xin Ren🇨🇳 · Emmanuel N. Saridakis🇬🇷 · Yi-Fu Cai🇨🇳

    In this article we use the latest cosmological observations, including SNe, BAO, CC and RSD, to reconstruct the cosmological evolution via the Gaussian process. At the background level, we find consistency with the quintom dynamics for different data combinations and divide the characteristics of dark energy into three different categories, which are negative-energy dark energy, late-dominated dark energy and oscillating dark energy, respectively. Considering the effect of modified gravity on the growth of matter perturbations, the reconstruction results at the perturbative level show that we only need minor corrections to general relativity. Furthermore, we provide theoretical interpretation for the three different types of dynamical dark-energy behavior, in the framework of modified gravity, scalar fields, and dark-energy equation-of-state parametrizations. Finally, we show that all of these models can be unified in the framework of effective field theory.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2025)·44 citations
24. 24*

    Unveiling the origin of XMM-Newton soft proton flares II. Systematics in the proton spectral analysis

    T. Mineo · V. Fioretti🇮🇹 · S. Lotti · S. Molendi · G. Lanzuisi · M. Cappi · M. Dadina · S. Ettori🇮🇹 · F. Gastaldello · R. Amato

    Low-energy protons entering the field of view of the XMM-Newton telescope scatter with the X-ray mirror surface and might reach the X-ray detectors on the focal plane. They manifest in the form of a sudden increase in the rates, usually referred to as soft proton flares. By knowing the conversion factor between the soft proton energy and the deposited charge on the detector, it is possible to derive the incoming flux and to study the environment of the Earth magnetosphere at different distances. We present the results of testing these matrices with real data for the first time, while also exploring the seasonal and solar activity effect on the proton environment. The selected spectra are relative to 55 simultaneous MOS and PN observations with flares raised in four different temporal windows: December-January and July-August of 2001-2002 (solar maximum) and 2019-2020 (solar minimum). The main result of the spectral analysis is that the physical model representative of the proton spectra at the input of the telescope is a power law. However, a second and phenomenological component is necessary to take into account imprecision in the generation of the matrices at softer energies.

    ↳ astro-ph.HEhep-phAstronomy & Astrophysic 2024·3 citations
25. 25*

    Split-even approach to the rare kaon decay $K\to \pi {\ell }^{+}{\ell }^{-}$

    Raoul Hodgson🇩🇪 · Vera Gülpers🇬🇧 · Ryan Hill🇬🇧 · Antonin Portelli🇬🇧

    In recent years the rare kaon decay has been computed directly at the physical point. However, this calculation is currently limited by stochastic noise stemming from a light and charm quark loop GIM subtraction. The split-even approach is an alternative estimator for such loop differences, and has shown a large variance reduction in certain quantities. We present an investigation into the use of the split-even estimator in the calculation of the rare kaon decay.

    ↳ hep-lathep-phPoS(2025)·7 citations
26. 26*

    Scattering of SIMPlectic Dark Pions

    Yannick Dengler🇦🇹 · Axel Maas🇦🇹 · Fabian Zierler🇬🇧

    We study the scattering of two identical pNGBs (pseudo-Nambu-Goldstone Bosons) in Sp(4) gauge theory with two mass-degenerate Dirac fermions in the pseudo-real fundamental representation. This theory serves as a realization of a SIMP (Strongly Interacting Massive Particles) Dark Matter model. SIMPs are an exciting dark matter candidate as they make use of a new relic density mechanism and provide potential solutions to the so-called small-scale structure problems. These theories are realized by a confining dark sector which includes non-perturbative signatures. While most of the research focuses on ChPT (Chiral Perturbation Theory), first-principle verification of these models is indispensable. In these proceedings we give an update on scattering properties in the most common channel and give an outlook on the projects that lie ahead.

    ↳ hep-lathep-phPoS(2025)·4 citations
27. 27*

    Gravitational waves from metastable cosmic strings in the delayed scaling scenario

    Yifan Hu🇨🇳 · Kohei Kamada🇨🇳

    Recent observations by pulsar timing arrays (PTAs) such as NANOGrav, EPTA, PPTA, and CPTA suggest the presence of nanohertz stochastic gravitational wave background (GWB). While such signals could be explained by gravitational waves from a network of metastable cosmic strings (CSs), standard scenarios involving the Kibble-Zurek mechanism triggered by a thermal potential face significant challenges. Specifically, these scenarios predict a GWB spectrum inconsistent with the non-detection at higher frequencies by LIGO-Virgo-KAGRA (LVK) for CSs with relatively large string tension. It is also difficult to prevent the monopole forming phase transition just before the CS forming symmetry breaking, which spoils the CS network formation. In contrast, a delayed scaling scenario, where the CSs start to emit GWs at a later time due to the dilution during inflation, alleviates these issues. This scenario allows for a larger string tension while monopoles are sufficiently diluted such that the CS network safely forms. In this study, we clarify the spectrum of stochastic GWB from metastable CSs in the delayed scaling scenario, consistent with the PTA observations while satisfying the LVK constraints. Furthermore, we explore its potential signatures at frequencies accessible to other detectors such as LVK as well as LISA, Taiji, and TianQin or DECIGO and BBO. We also discuss the implications on inflation and underlying UV theories, such as the grand unified theories.

    ↳ astro-ph.COgr-qchep-phJCAP(2025)·6 citations
28. 28*

    Avoiding Big Rip Singularities in Phantom Scalar Field theory with Gauss-Bonnet term

    Giannis Papagiannopoulos🇬🇷 · Genly Leon🇨🇱 · Andronikos Paliathanasis🇿🇦

    We consider a phantom scalar field coupled to the Gauss-Bonnet scalar within a spatially flat FLRW geometry. Moreover, we assume a nonzero interaction between the scalar field and the matter term. We perform a detailed phase space analysis using two sets of dimensionless variables. Specifically, we introduce dimensionless variables based on the Hubble normalization approach and a new set based on the matter-scalar field normalization. These two sets of variables allow for a comprehensive phase space analysis. This model supports inflationary solutions without the Big Rip or Big Crunch singularities appearing as asymptotic solutions. This outcome is attributed to the presence of the Gauss-Bonnet scalar. The result remains valid even in the absence of the interaction term.

    ↳ gr-qchep-phmath-phmath.MPAnnals Phys.(2025)·3 citations
29. 29*

    Chiral non-Abelian vortex molecules in dense QCD

    Sven Bjarke Gudnason🇨🇳 · Muneto Nitta🇯🇵

    The color-flavor locked phase of high density QCD admits non-Abelian vortices, that are superfluid vortices with confined color-magnetic fluxes. Vortex solutions were thus far constructed in an axially symmetric Ansatz with common vortex winding in the left- and right-handed diquark condensates. In this paper, we explore vortex solutions without any Ansatz. In addition to axially symmetric configurations known before, we find that the axial symmetry is broken in certain parameter regions; in one case a single vortex is split into two chiral non-Abelian vortices, i.e. vortices with winding only in the left or right-handed diquark condensate, and they are connected by one or two domain walls forming a non-Abelian vortex molecule. In the other case, a chiral non-Abelian vortex molecule is confined inside a domain wall elongated to spatial infinity.

    ↳ hep-thhep-phPRD(2025)·1 citation
30. 30*

    Towards more accurate $B_{(s)}\to \pi (K)$ and $D_{(s)}\to \pi (K)$ form factors

    Logan Roberts🇬🇧 · Chris Bouchard🇬🇧 · Olmo Francesconi🇬🇧 · Will Parrott🇨🇦

    We present progress on the calculation of scalar, vector, and tensor form factors for the following meson decays: $B\to \pi$, $B_s\to K$, $D\to \pi$ and $D_s\to K$. This calculation uses the MILC HISQ gluon field ensembles with HISQ valence quarks. We generate ensembles of correlator data with varying lattice spacings, some as small as 0.044 fm. Some ensembles have a strange-to-light quark mass ratio of 5:1 and others use the physical light quark mass. The fully-relativistic, heavy-HISQ approach is used for the heavy quark, with simulation masses ranging from the charm to near the bottom. This heavy-HISQ approach provides nearly full coverage of the kinematic range.

    ↳ hep-lathep-phPoS(2025)·1 citation

* 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.