Wed·May 20, 2026Wednesday·May 20, 2026

1. 01*

   Meson Octet in a Uniform Magnetic Field

   Prabal Adhikari🇺🇸

   Chiral perturbation theory is utilized to construct the renormalized magnetic masses and decay constants of the meson octet at next-to-leading order. While the neutral pion mass decreases identically to two-flavor chiral perturbation theory, the neutral kaon mass remains unaltered by the magnetic field. The renormalized magnetic masses for the charged mesons change identically. Meson decay constants in the axial and vector channels are constructed. Each of the decay constants increase monotonically in the magnetic background. Low-energy theorems -- Gell-Mann-Oakes-Renner relations for the neutral mesons and their generalization for the charged mesons through the pseudoscalar coupling -- are constructed and provide non-trivial crosschecks.

   hep-ph0 citations
2. 02*

   Looking at the Entropy in a Proton through a QGP Lens

   Dmitri E. Kharzeev🇺🇸 · Krishna Rajagopal🇺🇸

   We investigate the interplay between the thermodynamic (Gibbs) entropy of quark-gluon plasma (QGP) and the quantum entanglement entropy characteristic of confined hadronic states across the quark-hadron phase transition. In the deconfined regime, entropy is well described by the statistical mechanics of colored quarks and gluons. Upon hadronization, however, the macroscopic Gibbs entropy of the plasma cannot simply vanish; instead, it is reorganized into the configurational entropy of a gas of colorless hadrons together with quantum correlations among the confined partons within each hadron. We show that the entanglement entropy of the internal partonic wave functions inside hadrons provides a natural repository for this ``converted'' thermodynamic entropy, reconciling the apparent reduction of macroscopic entropy with the second law of thermodynamics. Either by extrapolating from known facts about deep inelastic scattering, or starting from model descriptions of the proton wave function, or starting from the Hagedorn spectrum of its resonances, we provide three estimates of the magnitude of the entanglement entropy carried by a proton, with very different uncertainties. All three estimates indicate that the internal entanglement entropy of the proton is similar in magnitude to the Gibbs entropy of the QGP droplet from which the proton formed as QGP cools through the quark-hadron transition, as for example throughout the universe microseconds after the Big Bang. These results suggest that entanglement entropy offers a bridge between the quantum information content of hadronic states and the thermodynamic entropy of the quark-gluon plasma, providing a new lens on the microscopic mechanism of confinement and the nature of the QCD phase transition.

   hep-phnucl-th3 citations
3. 03*

   Spectral fringes without subcycles in Schwinger pair production and Dirac materials

   I. A. Aleksandrov🇷🇺 · M. A. Dorodnyi🇷🇺 · E. D. Akimkina🇷🇺

   Spectral fringes in Schwinger pair creation are usually attributed to structured driving, such as carrier oscillations, pulse trains, or multiple creation events. We show that pronounced fringes can arise even for smooth, carrier-free single-lobe electric-field pulses. Two bell-shaped profiles that are nearly indistinguishable in real time - a Gaussian pulse and a weakly deformed variant - produce qualitatively different longitudinal momentum spectra in the nonadiabatic crossover: the Gaussian spectrum remains smooth, whereas the deformed pulse develops strong fringes as the Keldysh parameter approaches unity. Exact numerical solutions in scalar and spinor QED agree with a semiclassical turning-point analysis and trace the effect to a turning-point dominance transition, where the leading saddle becomes irrelevant and subleading contributions interfere. We demonstrate the same mechanism in a solid-state Schwinger analog described by a gapped two-dimensional Dirac model relevant to epitaxial graphene on SiC, and discuss an energy-resolved pump-probe route to observing the predicted modulation.

   hep-phcond-mat.mes-hall0 citations
4. 04*

   The canonical approach at high temperature revisited

   Kouji Kashiwa🇯🇵 · Hiroaki Kouno🇯🇵

   This paper discusses a paradox encountered when employing the canonical approach, particularly in the high-temperature region where the Roberge-Weiss transition exists at finite imaginary chemical potential. The paradox is that the results obtained using the canonical approach cannot match the correct results in that region. We show that the paradox originates from the Roberge-Weiss transition in the infinite-size system, which is linked to the non-trivial Polyakov-loop sectors. Furthermore, it is shown that this paradox disappears in finite-size systems because of the smearing effect for the Roberge-Weiss transition, which validates the use of the canonical approach in lattice QCD simulations.

   hep-phhep-lat0 citations
5. 05*

   The twist-3 gluon contribution to $A_N$ in $J/\psi$ production in $pp$ collisions

   Longjie Chen🇵🇱 · Shinsuke Yoshida🇨🇳

   We present our results for the twist-3 gluon contribution to the single transverse-spin asymmetry(SSA) in $J/\psi$ production in proton-proton collisions. Although the data were reported by the RHIC experiment more than a decade ago, a theoretical calculation based on rigorous collinear factorization has remained unavailable for the dominant gluonic contribution. Our results show that only the $C$-even type twist-3 gluon distribution, which has a direct relationship with the gluon TMD distribution function, contributes to the $J/\psi$ SSA. Therefore, this observable serves as a key probe to understand the three-dimensional motion of gluons inside the proton. We also perform numerical simulations of the $J/\psi$ SSA at RHIC and LHC energies. Our simulations indicate that a sizable SSA could be generated through a mechanism different from that responsible for the SSA in light hadron and $D$-meson production.

   hep-phPRD(2026)·0 citations
6. 06*

   Weak Triplet Models of Neutrino Magnetic Moments

   Svjetlana Fajfer🇸🇮 · Shaikh Saad🇸🇮

   Experimental limits on neutrino magnetic moments remain several orders of magnitude above the predictions of the Standard Model; therefore, any future detection would provide unambiguous evidence for new physics. In models with Dirac neutrinos, however, mechanisms that enhance the magnetic moment typically generate excessively large neutrino masses. Recently, it has been argued that in frameworks where neutrinos mix with weak-triplet Dirac fermions, the magnetic moment can be decoupled from the neutrino mass. In this work, we revisit this possibility and show that sizable enhancements remain highly nontrivial to realize naturally. We demonstrate that, although the minimal realization allows the magnetic moment to be decoupled from the neutrino mass, obtaining an observable enhancement requires a delicate adjustment of the model parameters. Moreover, in extended scenarios, the decoupling no longer persists: the magnetic moment and neutrino mass become intrinsically linked, such that attempts to enhance the former inevitably induce large contributions to the latter.

   hep-ph1 citation
7. 07*

   Top Pair Threshold Revisited

   Torbjörn Sjöstrand🇸🇪 · Valery A. Khoze🇬🇧 · Christian T. Preuss🇩🇪

   Recently the CMS and ATLAS collaborations have found evidence for an unexpectedly large ttbar cross section in the threshold region, with an excess of the order of 5-10 pb relative to continuum perturbative calculations. A convenient approach to the theoretical study of this region, unifying the above- and below-threshold behaviour, is the non-relativistic Green's function formalism. It was first applied to top production more than 35 years ago, well before the discovery of the top. We therefore revive and dissect the old formalism, and put it back together in a more consistent form, suited for Monte Carlo event generation. Combined with some practical prescriptions, it can be applied to current conditions. As an example, the below-threshold cross section comes out to be of the order of 6.5 pb, i.e. comparable with the CMS and ATLAS numbers. The new code is publicly available in the Pythia event generator so can be used for more detailed comparisons.

   hep-phhep-ex1 citation
8. 08*

   A comparative study of $T_{cc}$ versus $X(3872)$ production in $pp$ collisions at $\sqrt{s}=$ 7 TeV

   Hongge Xu🇨🇳 · Tianqi Luo🇨🇳 · Yi-Long Xie🇨🇳 · Zhi-Lei She🇨🇳 · Ning Yu🇨🇳 · Zuman Zhang🇨🇳

   The production of exotic hadrons $T_{cc}$ and $X(3872)$ in $pp$ collisions at $\sqrt{s}=7$ TeV is compared using the parton and hadron cascade model PACIAE together with the dynamically constrained phase-space coalescence model DCPC. In the simulation, the compact tetraquark state and the loose molecular state are formed in the partonic and hadronic levels, respectively. Our analysis of the transverse momentum spectra reveals a significant discrepancy between the compact state and the molecular states. Furthermore, the production asymmetry between $T_{cc}^{+}$ and $T_{cc}^{-}$ is investigated. Finally, the coalescence parameters are extracted from the calculated spectra to further characterize the emission source properties. These distributions are proposed as valuable criteria for distinguishing between these states and investigating their internal structures in experimental measurements.

   hep-ph0 citations
9. 09*

   Controlling Quantum discord and steering in Electron-Positron Annihilation Using Polarized Beams

   Hong-Wei Zhang🇨🇳 · Xu Cao🇨🇳 · Tai-Fu Feng🇨🇳

   Quantum discord and steering offer crucial insights into the non-classical nature of hyperon-antihyperon pairs, a massive two-qubit system produced in high energy electron-positron annihilation. This work theoretically investigates the generation and control of these quantum correlations by leveraging longitudinal and transverse polarization of lepton beams. By exploiting the joint spin density matrix of hyperon pairs, the sensitivity of quantum discord and steering to the beam polarization degree are numerically quantified. Our analysis reveals distinct angular regimes where beam polarization can enhance steering and discord. Hierarchy of different quantum correlations are examined under the case of polarized lepton beams by constructing a measure in the spirit of entanglement of formation. It is confirmed that quantum discord remain non-zero even in regions with vanishing entanglement corresponding to separable states, controlled via transversely polarized beams. As an experimentally tunable parameter, beam polarization offers an effective means to manipulate the quantum correlation of hyperon-antihyperon systems, thereby providing a practical route for preparing and probing quantum states in high-energy particle physics.

   hep-ph5 citations
10. 10*

    The stability of color-flavor-locked quark matter and massive CFL quark stars

    Wen-Li Yuan🇨🇳 · Bikai Gao🇯🇵

    Owing to the emergence of attractive interactions between quarks, color superconductivity is expected to occur, with the color-flavor-locked (CFL) phase favored at high densities. This work investigates the absolute stability of beta-equilibrated CFL quark matter in bulk within the modified Nambu-Jona-Lasinio model, under color and electric charge neutrality conditions relevant to compact stars. Motivated by the possible existence of an ultra-low-mass central compact object in the supernova remnant HESS J1731-347 and the "mass-gap" secondary component in the GW190814 event, we systematically explore how vector repulsion, attractive diquark pairing, and nonperturbative vacuum effects influence the stiffness of CFL quark matter and its stability. Our findings suggest the existence of a physically viable region of parameter space in which the CFL phase is the true ground state of strongly interacting matter, thereby theoretically supporting the scenario of self-bound quark stars. This configuration is not only consistent with current astrophysical constraints from NICER and LIGO/Virgo observations, but also provides a possible explanation for both the $2.6M_{\odot }$ secondary component in GW190814 and the ultra-low-mass compact object with $M=0.77_{-0.17}^{+0.20}{M}_{\odot }$in HESS J1731-347.

    hep-phastro-ph.HEnucl-th2 citations
11. 11*

    Redetermination of proton sea distributions

    Alim Ruzi🇨🇳 · Bo-Qiang Ma🇨🇳

    The shapes of light flavor sea quark distributions of the proton are examined directly from two rounds of NNLO global analysis of HERA $e^{\pm }p$ deep inelastic scattering cross section measurements, termed as HERAshape and the ATLAS measurement of $W^{\pm }/Z$ production from $pp$ collision at $\sqrt{s}$ = 7 TeV, termed as ATLASshape. An asymmetric distribution between anti-up ($\text{ubar}$) quark and anti-down ($\text{dbar}$) quark is found in both analysis, showing that the anti-up quark distribution exceeds over anti-down quark distribution in the momentum fraction range $x\in (10^{-2},1)$ of these partons. The Gottfried Sum Rule is reevaluated from these extracted parton distribution functions and the obtained value differs surprisingly from that of the NMC and the NuSea Collaborations.

    hep-ph1 citation
12. 12*

    Probing the Rare Four-Bottom Higgs Decay $H\to b\bar{b}b\bar{b}$ at the HL-LHC and ILC

    Alexander Belyaev🇬🇧 · Eduard Boos🇷🇺 · Vyacheslav Bunichev🇷🇺 · Guliya Nurbakova🇰🇿 · Saniya Rustembayeva🇰🇿

    We propose the rare SM Higgs decay $H\to b\bar{b}b\bar{b}$ as a probe of the structure of Higgs interactions with bottom quarks and gauge bosons, and as a baseline for searches for new physics producing four-bottom final states in Higgs decays. We compute the leading contributions to this decay, including the dominant $H\to b\bar{b}g\to b\bar{b}b\bar{b}$ topology, the sizeable $H\to Z{Z}^{\ast }\to b\bar{b}b\bar{b}$ channel, and the loop-induced $H\to gg\to b\bar{b}b\bar{b}$ contribution. We find a branching ratio of order $1.6\times 10^{-3}$ and show that destructive interference among the leading amplitudes is phenomenologically relevant. We demonstrate that this decay can be probed in associated Higgs production at both the HL-LHC and the ILC. For $pp\to WH\to Wb\bar{b}b\bar{b}$ at $\sqrt{s}=14$ TeV, we use a multivariate analysis based on boosted decision trees to exploit correlations among the four-$b$ kinematic observables. At $3000{\mathrm{fb}}^{-1}$, the statistical significance reaches about $3.5$, while a tighter high-purity working point gives $S/B\simeq 5\%$ with significance close to $3\sigma$. A combined high-luminosity LHC dataset could therefore make this rare decay observable. For $e^{+}{e}^{-}\to ZH\to Zb\bar{b}b\bar{b}$ at the ILC with $\sqrt{s}=250$ GeV, we demonstrate that the cleaner collider environment gives a high-purity signal sample. In the nominal setup, the multivariate analysis gives a significance above $5\sigma$ already at $300{\mathrm{fb}}^{-1}$. At integrated luminosities of order $1-3{\mathrm{ab}}^{-1}$, the branching ratio can be measured with several-percent precision.

    hep-phhep-exhep-th0 citations
13. 13*

    Lee-Yang zeros and edge singularity in a mean-field approach

    Tatsuya Wada🇯🇵 · Győző Kovács🇵🇱 · Masakiyo Kitazawa🇯🇵 · Takahiro M. Doi🇯🇵

    The analytic structure of the partition function in finite-volume systems is investigated at complex chemical potentials in a minimal mean-field effective model of QCD with finite-size effects incorporated. We discuss the temperature dependence of the Lee-Yang zeros and their relation to the edge singularity for various system sizes. Different methods for locating the critical point based on finite-size scaling of Lee-Yang zeros and susceptibility ratios are compared. We demonstrate that these methods can successfully identify the critical point, whereas a careful treatment of corrections from irrelevant operators is crucial for its accurate determination.

    hep-phPRD(2026)·1 citation
14. 14*

    Lindblad-driven quarkonium production in heavy-ion collisions

    Néstor Armesto🇪🇸 · Miguel Ángel Escobedo🇪🇸 · Elena G. Ferreiro🇪🇸 · Víctor López-Pardo🇪🇸

    We study the production of the conventional quarkonium states in ultrarelativistic heavy-ion collisions using an open quantum system framework based on the Lindblad equation. Starting from the complex-valued in-medium potential, we derive the dissociation temperature and thermal decay width for each state, and compute their survival probabilities for a system undergoing Bjorken expansion. We then extend the framework to include recombination from thermalized charm and bottom quarks in the quark-gluon plasma, deriving a coalescence model for quarkonia from the Lindblad equation under the adiabatic approximation. The methodology provides a unified, first-principles-inspired description of suppression and recombination for both charmonium and bottomonium.

    hep-phhep-exnucl-exnucl-th5 citations
15. 15*

    Renormalisation and invariants for two U(1)s

    Sacha Davidson🇫🇷 · Martin Gorbahn🇬🇧

    We revisit the renormalisation of models with two U(1) gauge symmetries, in a formulation with non-canonical gauge kinetic terms which is covariant under field reparametrisations among the two gauge bosons. This approach is convenient to study the appearance of kinetic mixing in scale evolution, because a coupling matrix is attributed to the gauge kinetic terms. We obtain simple MSbar renormalisation group equations up to two-loop, which can be solved to give effective millicharges at low energy which depend on the running couplings and heavy mass scales of the model. This formulation allows to construct ``invariants'' out of running Lagrangian parameters, which are invariant under generic gauge field reparametrisations, including rescalings, and which can be related directly to observables such as the millicharge.

    hep-ph0 citations
16. 16*

    Non-Relativistic Cosmological Collider Signals

    Matheus C. Ferreira🇧🇷 · F. T. Falciano🇧🇷

    We investigate a non-relativistic realization of the boostless cosmological collider in a scenario where inflationary interactions are mediated by a massive tilted-ghost spectator field. Unlike standard boostless collider constructions, in which the characteristic non-Gaussian signatures are mainly generated by boost-breaking interaction vertices, the dominant effect in the present framework arises directly from the propagation of the spectator modes. Non-relativistic corrections deform the bulk mode functions, inducing a tilt that modifies the in-in correlators and generates a distinctive collider signal. The resulting squeezed-limit non-Gaussianity reproduces the qualitative structure of boostless cosmological-collider signals while originating from a fundamentally different dynamical mechanism. A central feature of the construction is the emergence of an effective chemical-potential-like parameter that controls the relative weight of the two late-time oscillatory branches. However, the tilted-ghost mode exhibits distinctive dynamical features and does not correspond to a conventional chemical-potential deformation. Depending on the sign of the tilt, the corresponding non-Gaussian signal can be either enhanced or suppressed. We show that the tilted-ghost scenario provides a simple effective framework in which boostless-collider phenomenology and chemical-potential-like branch asymmetries arise naturally from non-relativistic propagation effects.

    hep-phgr-qchep-thJCAP(2026)·1 citation
17. 17*

    Dark Matter Interpretation of the Super-Kamiokande Antineutrino Excess and Predictions for JUNO

    Alessandro Granelli🇪🇸 · Silvia Pascoli🇮🇹 · Salvador Rosauro-Alcaraz🇫🇷

    Super-Kamiokande has reported a small excess of electron antineutrino events in the 20 MeV energy range, in the search for the diffuse supernova neutrino background. We interpret this signal as a possible indication of dark matter that annihilates dominantly into neutrinos, pointing to a thermal dark matter candidate with $s$-wave annihilation and with mass in the tens of MeV range. This mass scale naturally fits into rich dark sector extensions of the Standard Model. Neutrino experiments, including JUNO, will be able to test this hypothesis in the coming years.

    hep-phastro-ph.CO3 citations
18. 18*

    WIMP-like Dark Matter Without Thermalization At Freeze-Out

    Dan Hooper🇺🇸 · Gordan Krnjaic🇺🇸 · Gabriele Montefalcone🇺🇸

    In the standard thermal relic scenario, dark matter remains in chemical equilibrium with the Standard Model radiation bath until freeze-out occurs at $T\sim m_X/20$, where $m_X$ is the dark matter mass. In this familiar class of models, the observed relic density is obtained for annihilation cross sections of order $\sigma v\sim 10^{-26}$ cm${}^3$/s. We show that comparable cross sections can naturally be realized in hidden-sector models in which the dark matter and Standard Model sectors decouple at a very high temperature, $T\gg m_X$, and subsequently evolve with separate thermal histories. Despite this decoupling, the two sectors have similar temperatures during freeze-out, leading to the usual thermal relic abundance. As a consequence, the coupling between the Standard Model and hidden sectors can be extremely small, potentially placing direct detection and collider signals far below foreseeable sensitivities.

    hep-phastro-ph.COhep-th0 citations
19. 19*

    Model-Building Implications from Light Magnetic Monopoles: A Case Study of Flavour Deconstruction

    Marko Pesut🇨🇭 · Davide Racco🇨🇭 · Yunlong Zhao🇨🇭

    We highlight a generic connection between extensions of the Standard Model featuring low-scale semi-simple embeddings of $\mathrm{U}(1{)}_{\mathrm{EM}}$ and the phenomenology of light magnetic monopoles in the early Universe. Combining cosmological, astrophysical, and direct-search constraints, we show that magnetic monopoles with masses far below the scale of Grand Unified Theories are generically excluded and require low-scale inflation to dilute their abundance, followed by reheating below the monopole-production scale. These constraints are particularly relevant for flavour non-universal models, which provide a well-motivated framework to address the hierarchical structure of Yukawa couplings while allowing new dynamics close to the TeV scale compatible with experimental bounds. In many of these constructions, the sequential breaking of semi-simple gauge groups through intermediate stages containing a $\mathrm{U}(1)$ factor generically leads to the production of light magnetic monopoles. We show that the parameter region naturally predicted by these models implies low-scale inflation, with reheating temperature as low as $10^3\text{–}10^4\mathrm{TeV}$. These results significantly reduce the otherwise large allowed inflationary window and establish a direct connection between flavour physics and the thermal history of the early Universe: future evidence for a low-scale semi-simple embedding of $\mathrm{U}(1{)}_{\mathrm{EM}}$, in particular through flavour non-universal interactions, would point towards low-scale reheating, while probes of primordial gravitational waves could directly constrain the scale at which low-scale semi-simple groups can appear.

    hep-phastro-ph.COgr-qc1 citation
20. 20*

    Indirect Parametric Resonance of the Electromagnetic Field Driven by an Oscillating SU(2) Dark Matter Condensate

    Tatsuya Daniel🇨🇦 · Vahid Kamali🇨🇦 · Robert Brandenberger🇨🇦

    We study a local patch of an axion-like dark sector in Minkowski spacetime, containing an initially homogeneous and isotropic non-Abelian $SU(2)$ condensate, and a real pseudoscalar field $\chi$, coupled to an Abelian $U(1)$ gauge field which could be that of usual electromagnetism. The pseudoscalar couples directly to both gauge sectors through Chern-Simons interactions, while the $U(1)$ field couples to the $SU(2)$ condensate only indirectly, through the pseudoscalar. We show analytically that a homogeneous oscillating $SU(2)$ background $Q(t)$ acts as a periodic source for $\chi$, generating a homogeneous oscillatory condensate $\dot{\chi }$ that in turn modulates the frequency of the $U(1)$ helicity modes. In the linear regime this produces a Hill equation, and when the first harmonic dominates it reduces to a Mathieu equation. We derive the approximate resonance conditions, the leading Floquet exponent, and the conditions for a two-stage enhancement $Q\to \chi \to U(1)$. We also highlight an important point: in the exactly periodic, zero-bias limit, the indirect resonance is not intrinsically chiral, because the two Abelian helicities are related by a half-period time shift.

    hep-phastro-ph.COgr-qchep-th2 citations
21. 21*

    Gauged Flavour for Asymmetric Dark Matter

    Mattias Blennow🇸🇪 · Enrique Fernandez-Martinez🇪🇸 · David Garcia-Garcia🇪🇸 · Javier M. Lizana🇪🇸

    We propose a framework that links the origin of the Standard Model flavour hierarchies to the generation of asymmetric dark matter via leptogenesis. The key new ingredient is a gauged $SO(3)$ flavour symmetry acting on both the visible and dark sectors, whose spontaneous breaking generates fermion mass hierarchies. Right-handed neutrino decays produce a primordial lepton asymmetry, which is redistributed into baryon and dark matter asymmetries by electroweak and flavour sphalerons respectively. Dark matter arises as baryon-like bound states of a confining $SU(3)$, providing a natural rationale for the similar mass scales of visible and dark matter. We analyze flavour, collider, electroweak, and cosmological constraints. Anomaly cancellation requires the presence of mirror fermions, inducing a seesaw-like suppression of new physics effects in the lighter generations, such that different observables are sensitive to different flavour-breaking scales. Meson oscillations provide the dominant constraints, with $K$ and $B_s$ observables constraining the highest and intermediate scales, while the lowest scale may place some mirror fermions potentially within reach of future collider searches and is currently probed by flavour violating $B_s$ decays and electroweak observables. Flavour interactions are also bounded from below by the requirement of a sufficiently fast decay of the symmetric dark matter component, leading to a tightly constrained and predictive scenario testable through several complementary probes.

    hep-ph2 citations
22. 22*

    Quantum Magic Reveals CP Phases Invisible to Entanglement in Spin-0 Decays

    Nicolas Viaux🇨🇱 · Ariel Norambuena🇦🇲 · Pedro Orellana🇦🇲

    All standard scalar quantum-information measures -- concurrence, negativity, entanglement entropy, the optimized CHSH bound, and quantum Fisher information -- are CP-blind in ideal \\ spin-0 $\to f\bar{f}$ decays because the two-qubit spin state is maximally entangled for every CP angle. We show that stabilizer magic, fixed in the physical Pauli frame of spin analysis, escapes this blind spot: the stabilizer Rényi entropy admits an exact closed form, vanishing at CP-definite and Clifford phases and peaking at maximal non-Clifford mixing. Two experimentally accessible, magic-inspired CP witnesses follow; the linear amplitude is $14.3\times$ more efficient than its quartic counterpart and reaches discovery-level sensitivity at the HL-LHC for $H\to {\tau }^{+}{\tau }^{-}$.

    ↳ quant-phhep-phhep-thPRD(2026)·2 citations
23. 23*

    Ab initio correlations between neutrinoless and two-neutrino double-beta decays in ${}^{48}$Ca

    X. Lian🇨🇳 · C. R. Ding🇨🇳 · C. L. Bai🇨🇳 · J. M. Yao🇨🇳

    We develop a novel ab initio in-medium no-core configuration-interaction (IM-NCCI) framework for nuclear charge-exchange processes by combining the in-medium similarity renormalization group with chiral nuclear Hamiltonians, and apply it to the $2\nu \beta \beta$ and $0\nu \beta \beta$ decays of ${}^{48}$Ca. This framework reproduces the locations of several main resonance peaks in the Gamow-Teller (GT) strength distribution for the ${}^{48}\mathrm{Ca}\to {}^{48}\mathrm{Sc}$ transition. The cumulative GT strength indicates missing contributions from two-body weak currents, corresponding to an effective quenching factor of $q\simeq 0.84$. Incorporating this quenching yields a $2\nu \beta \beta$ nuclear matrix element (NME) in excellent agreement with experiment. Applying the same framework to $0\nu \beta \beta$ decay, and including the contribution from short-range operators, we obtain a total NME of $M^{0\nu }=1.00\text{-}2.02$. Using 34 non-implausible chiral Hamiltonians, we establish from first principles strong linear correlations between the $0\nu \beta \beta$ NME and the NMEs governing $2\nu \beta \beta$ decay and double GT transitions. Combining these correlation relations within the 95% confidence level with the experimental $2\nu \beta \beta$-decay data yields a constrained prediction of $M^{0\nu }=1.30\text{-}1.65$. This work establishes IM-NCCI as a complementary ab initio framework for nuclear weak decays and opens a pathway toward constraining $0\nu \beta \beta$ NMEs in heavier candidate nuclei using experimentally accessible $2\nu \beta \beta$-decay data.

    ↳ nucl-thhep-phnucl-ex4 citations
24. 24*

    Inflaton Accretion onto Primordial Black Holes During Reheating

    Jitumani Kalita🇮🇳 · Debaprasad Maity🇮🇳

    Primordial Black Holes (PBHs) forming prior to Big Bang Nucleosynthesis evolve during the reheating epoch, an environment dominated by an oscillating inflaton field decaying into a relativistic thermal bath. In this work, we track the complete lifecycle of PBHs within this coupled inflaton-radiation background. Utilizing $\alpha$-attractor E-models, we analytically anchor the reheating initial conditions directly to Cosmic Microwave Background observations. By matching exact scalar field solutions in a Schwarzschild spacetime to the cosmological far-zone, we derive the cycle-averaged mass accretion rate and couple it to the growing radiation bath. We find that this combined accretion induces a highly non-linear enhancement of the final PBH mass. Because the Hawking evaporation timescale scales cubically with mass, PBHs forming near their critical runaway limits experience a massive extension of their lifespans. Surviving deeper into the radiation-dominated era triggers a multi-order-of-magnitude amplification in their emitted Stochastic Gravitational Wave Background (SGWB).

    ↳ astro-ph.COgr-qchep-ph0 citations
25. 25*

    Domain-wall Quintessence

    Nobufusa Kobayashi🇯🇵 · Yuichiro Tada🇯🇵 · Fuminobu Takahashi🇯🇵 · Takahiro Terada🇯🇵

    We investigate a dark energy model driven by a planar domain-wall-like structure with a thickness comparable to, or larger than, the current Hubble radius, focusing on its intrinsic anisotropy and observational viability. Near the centre of the domain wall (DW), the spacetime is anisotropic, with distinct expansion rates parallel and perpendicular to the wall. This anisotropic structure induces direction-dependent cosmic expansion and modifies photon geodesics from cosmological sources, leaving characteristic signatures in cosmological observables. We confront the model with recent observational data. We first compute the anisotropic Cosmic Microwave Background (CMB) temperature multipoles generated by the DW and impose constraints from the Planck 2018 measurements. These constraints severely limit the allowed DW abundance, requiring the DW energy density to be less than $\mathcal{O}(10^{-5})$ of the current critical density in order to suppress the quadrupole contributions. We then perform a Markov Chain Monte Carlo (MCMC) analysis using Type Ia supernova (SNe Ia) data, including the Pantheon+ SH0ES and DESY5 samples, to compare the DW scenario with the standard $\Lambda$CDM model. We find that although the DW naturally realises anisotropic accelerated expansion, the combined constraints from the CMB and SNe Ia favour the $\Lambda$CDM limit, in which the DW contribution is negligible, and the universe is effectively isotropic. Our results demonstrate that a Hubble-scale domain wall is tightly constrained by current observations and can only play a subdominant role in the late-time cosmic acceleration.

    ↳ astro-ph.COgr-qchep-ph0 citations
26. 26*

    A new analysis of the "hep" S-factor and the "hen" cross section

    Michele Viviani🇮🇹 · Alex Gnech🇺🇸 · Laura Elisa Marcucci🇮🇹 · Alejandro Kievsky🇮🇹 · Luca Girlanda🇮🇹

    We present a new accurate analysis of the ${}^3$He$(p,e^{+}{\nu }_e)$${}^4$He (''hep'') reaction at astrophysical energies. The S-factor is computed using a state-of-the-art method to calculate the four-nucleon scattering and bound-state wave functions (the hyperspherical harmonic expansion), and by using nuclear interactions and accompanying electroweak nuclear currents obtained within the chiral effective field theory framework. Our analysis includes a detailed examination of the theoretical uncertainties coming from two different sources: the truncation of the interaction and current chiral expansions, and the model dependence. Our recommended final theoretical value for the hep S-factor at zero energyis $S(0)=(8.7\pm 0.9)\times 10^{-20}$ keV b. We provide also the energy spectrum of the outgoing hep positrons which may be measured in future experiments. We include also an analysis of the ''sister'' reaction ${}^3$He$(n,\gamma )$${}^4$He (''hen'') at low energies, showing that the calculation well reproduce the total cross section from thermal energies to few MeV, validating our results on the hep reaction.

    ↳ nucl-thastro-ph.SRhep-phnucl-ex0 citations
27. 27*

    Probing String-Theory-Inspired Topologies of the Early Universe through CMB Temperature and Polarization Anisotropies

    Nick E. Mavromatos🇬🇷 · Miguel-Angel Sanchis-Lozano🇪🇸

    TeV string-mass-scale strings have been excluded experimentally at colliders, as their effects have not been observed at the Large Hadron Collider (CERN). On the other hand, higher-scale string theory, with mass scales typically close to the Planck scale, is often regarded as experimentally inaccessible due to the enormous energies required for direct tests, and far beyond the reach of present or foreseeable particle accelerators. Nevertheless, the early Universe may provide an indirect observational window for high-string scale through imprints left on the Cosmic Microwave Background (CMB). In this work, building on previous studies, we reexamine temperature and polarization angular correlations as probes of the geometry and topology of the pre-inflationary Universe. We focus in particular on two-point correlation functions at large angular scales, where signatures of nontrivial spatial topology may survive as relics of primordial physics. We investigate the observational consequences of toroidal compactification and analyze their impact on the primordial power spectrum of the CMB provided by the Planck satellite. Within the current experimental and theoretical uncertainties, we identify a possible indication closely related to spatial-parity breaking, consistent with the presence of six spatial extra dimensions in the early Universe, compactified at the GUT epoch before the start of inflation. Finally, we extend our framework to B-mode polarization, highlighting its potential as a sensitive probe in forthcoming ground-based and space-borne experiments with unprecedented precision.

    ↳ astro-ph.COgr-qchep-phhep-th0 citations
28. 28*

    Charmonium properties at high temperatures from lattice QCD

    Rasmus Normann Larsen🇩🇪 · Peter Petreczky🇺🇸 · Jorge Luis Dasilva Golan🇺🇸 · Johannes H. Weber🇩🇪

    We study charmonium properties at non-zero temperature in the temperature range 153 MeV $<T<$ 305 MeV using lattice QCD. We use HISQ action for dynamical quarks and Wilson clover action for valence charm quarks and calculate the correlation function of extended meson operators. Our lattice QCD results are consistent with the existence of all charmonium states below the open charm threshold in this temperature region. However, charmonium states acquire sizable thermal width, which increases with increasing temperature. The size of the thermal width follows the hierarchy of charmonium sizes, i.e. the smaller ground state charmonium has a smaller thermal width than the larger excited charmonia.

    ↳ hep-lathep-phnucl-th1 citation
29. 29*

    The potential of diffuse Galactic Ridge neutrino measurements to constrain dark matter

    Jaume Zuriaga-Puig🇪🇸 · Pedro de la Torre Luque🇪🇸 · Viviana Gammaldi🇪🇸

    We use the latest ANTARES Galactic Ridge neutrino measurements to investigate their implications for indirect dark matter (DM) searches. We consider both annihilating and decaying DM scenarios, spanning a wide range of masses and final states, and systematically compare the resulting neutrino fluxes with the expected astrophysical Galactic diffuse emission. Furthermore, we compare the results for different DM density profiles allowed by the observations, from spike and cuspy to cored profiles. We do so for the WIMP model-independent scenario and explore two more specific models: branons and very heavy sterile neutrinos, where a cold DM candidate arises naturally from the theory. We show the potential neutrino measurements in the Galactic Ridge for DM and make predictions for future neutrino observatories.

    ↳ astro-ph.HEastro-ph.GAhep-phPhys.Dark Univ.(2026)·1 citation
30. 30*

    The Equivalence Principle at High Energies Completes the Spectrum

    Francesco Calisto🇺🇸 · Clifford Cheung🇺🇸 · Grant N. Remmen🇺🇸 · Francesco Sciotti🇪🇸 · Michele Tarquini🇺🇸

    We prove a version of the completeness hypothesis that follows from the coexistence of symmetry and gravity: tree-level gravitational scattering mandates single-particle states in all possible irreducible representations of the symmetry group constructible from a single seed charge. Our main assumption is that the leading high-energy behavior of scattering is universal irrespective of charge, thus satisfying the equivalence principle. Curiously, we discover that these newly-deduced states contribute democratically - that is, with equal interaction strengths - to scattering.

    ↳ hep-thhep-ph3 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.