Fri·Feb 13, 2026Friday·February 13, 2026

1. 01*

   Constraints on dark axion portal: missing energy and fermion EDMs

   Sergei N. Gninenko🇷🇺 · N. V. Krasnikov🇷🇺 · Valery E. Lyubovitskij🇨🇱 · Sergey Kuleshov🇨🇱 · Alexey S. Zhevlakov🇷🇺 · I. V. Voronchikhin🇷🇺 · D. V. Kirpichnikov🇷🇺

   We study a model in which a new interactions between the Standard Model (SM) photon and both the dark photon (${\gamma }_D)$ and an ALP ($a$) are described by the dark axion portal operator. The implications of this dark axion portal scenario for electron fixed-target experiments are presented. In particular, we investigate the missing energy signatures associated with production of dark photons and their subsequent invisible decays into stable dark sector fermions, ${\gamma }_D\to \chi \bar{\chi }$. We discuss the discovery potential for such a scenario and derive projected sensitivity curves for the NA64$e$ and LDMX experiments. Furthermore, novel constraints of the NA64$e$ for $9.37\times 10^{11}$ electrons on target are derived by considering two production mechanisms for invisible states: (i)~the bremsstrahlung-like emission of an $a{\gamma }_D$ pair, $eN\to eN{\gamma }^{\ast }(\to a{\gamma }_D)$, and (ii)~the exclusive vector meson photoproduction, ${\gamma }^{\ast }N\to NV$, followed by the invisible decays of vector mesons, $V\to a{\gamma }_D$. Additionally, the constraints on the parameter space of $CP$-violating, fermion-specific ALP and dark photon couplings are established. These constraints are derived from current experimental bounds on the electric dipole moments (EDMs) of SM fermions, incorporating loop-induced contributions to the EDMs of the electron, muon, and neutron.

   hep-phPRD(2026)·5 citations
2. 02*

   A study of charged-particle multiplicity distribution in high energy p-O collisions

   Yuri N. Lima🇧🇷 · Lucas J. F. Silva🇧🇷 · Andre V. Giannini🇵🇹 · Marcelo G. Munhoz🇧🇷

   This study investigates the multiplicity distribution of charged particles generated in $p$-O collisions, employing Pythia (Angantyr) and $k_T$-factorization approach. Oxygen nucleus configurations are sampled using a $\alpha$-cluster model to evaluate both formalisms and assess how initial nucleus configuration influences the properties of the produced final states. Results obtained through clustering are systematically compared to those derived from the Woods-Saxon nuclear distribution. The analysis encompasses various pseudorapidity intervals ($|\eta |<$ 0.5, 1.0, 2.0, 3.0) and center-of-mass energies ($\sqrt{s}=$ 2.36, 5.02, 7.0, 13.0 TeV). Based on the resulting distributions, we examine the KNO scaling effect and fit the distributions with the double NBD model for parameterization, aiming to accurately characterize the observed results and elucidate contributions from both soft and semi-hard processes. Our results indicate that different geometric descriptions of the oxygen nucleus project significantly different multiplicities of charged particles, especially for large multiplicities and higher pseudorapidity. We also observed that multiplicity of charged particles calculated with Pythia reveals significantly different behavior from that calculated with $k_T$-factorization.

   hep-phhep-exnucl-th0 citations
3. 03*

   The absence of global anomalies of CP symmetry

   Kazuya Yonekura🇯🇵

   Some solutions to the strong CP problem assume that CP symmetry is a gauge symmetry, which is then spontaneously broken. For this scenario to be possible, the CP symmetry should not have any nonperturbative (global) anomalies. In this paper, we study anomalies of CP symmetry of fermions which are coupled to gravity and gauge fields with a gauge group $G$. When $G$ is connected and simply connected, we show that gauging a CP symmetry does not produce any new anomaly beyond the one before gauging it. In particular, the standard model matter content does not have anomalies.

   hep-phhep-thJHEP(2026)·1 citation
4. 04*

   Triple Differential Heavy-to-light Semi-leptonic Decays at Next-to-Next-to-Next-to-Leading Order in QCD

   Long Chen🇨🇳 · Xiang Chen🇨🇭 · Xin Guan🇺🇸 · Yan-Qing Ma🇨🇳

   We report the first complete calculation of the five heavy-to-light hadronic structure functions underlying semi-leptonic heavy-quark decays at next-to-next-to-next-to-leading order ($\mathcal{O}({\alpha }_s^3)$) in perturbative QCD. This theoretical advance, achieved via an innovative hybrid computational strategy, enables precision predictions for triple differential decay rates. The results are essential for harnessing the potential of high-precision experiments at Belle II, BES III, and LHCb. Selected applications of this work include a state-of-the-art prediction for the inclusive $B\to X_u\ell \nu$ width, crucial for a percent-level determination of $|V_{ub}|$, and the first $\mathcal{O}({\alpha }_s^3)$ results for lepton-energy moments in charm decays, vital for extracting $|V_{cs}|$ and $|V_{cd}|$. Our analysis also reveals significant higher-order corrections in the large-$q^2$ region of $b\to u$ transitions, offering new insights into the persistent tension between inclusive and exclusive $|V_{ub}|$ determinations.

   hep-phhep-ex3 citations
5. 05*

   Multi-Particle Invariant Mass -- Standard Expressions and Corrections to Order $(m/E{)}^4$

   M. P. Fewell🇦🇺

   In collider-based particle physics, $invariantmass$ refers to the magnitude of the total-momentum 4-vector of a system of particles. An expression for the invariant mass of a 2-particle system is well known; it assumes that both the total energy $E$ and the transverse momentum $p_{\mathrm{T}}$ of each particle in the system greatly exceed its mass $m$. This note explores these assumptions by computing correction terms in powers of $m/E$ up to order $(m/E{)}^4$. The assumptions are found to be robust: not only is the leading correction quadratic in $m/E$, but also cancellations reduce its coefficient and that of the next-to-leading correction, which is of order $(m/E{)}^4$. Three- and four-particle systems are also treated and the generalisation to larger numbers of particles indicated. The zeroth-order expressions for these multi-particle systems are remarkably simple; they deserve to be better known.

   hep-ph0 citations
6. 06*

   Probing mixed-state dark matter and flavor observables in a scalar-assisted baryonic gauge theory

   Taramati🇮🇳 · Manas Kumar Mohapatra🇮🇳 · Utkarsh Patel🇮🇳 · Rukmani Mohanta🇮🇳 · Sudhanwa Patra🇮🇳

   We explore a {standard model} extension based on a local $U(1{)}_B$ symmetry, where a baryon-charged scalar mediates interactions between a fermionic dark matter candidate and {standard model} quarks. In this setup, the dark matter relic abundance is shaped not only by standard annihilation channels but also by additional coannihilation processes induced by a new scalar. The presence of this mediator provides a unified link between {dark sector} and flavor physics, yielding distinctive phenomenological consequences. We conduct a detailed study of dark matter phenomenology, emphasizing the role of the mass splitting between the dark matter particles and the scalar mediator in determining the efficiency of coannihilation. The parameter space is examined in light of existing constraints from cosmological observations, direct and indirect detection experiments, as well as the collider searches at the {\text{LHC}}. Our analysis shows that the extended scalar sector opens up viable regions of parameter space beyond those accessible in minimal \(U(1)_B\) realizations, many of which are expected to be tested by forthcoming searches at {\text{XENONnT}} and {the \text{Cherenkov Telescope Array}}. Moreover, the model induces correlated signatures from flavor observables associated with the $b\to s$ transitions as well, serving as complementary tests of the underlying framework.

   hep-phPRD(2026)·0 citations
7. 07*

   Generalizing the Soffer Bound: Positivity Constraints on Parton Distributions of Spin-3/2 Particles

   Dongyan Fu🇨🇳 · Yubing Dong🇨🇳 · S. Kumano🇨🇳 · Ju-Jun Xie🇨🇳

   We derive the complete set of positivity bounds for the leading-twist parton distribution functions (PDFs) of a spin-3/2 hadron for the first time. This work generalizes the Soffer bound, a fundamental constraint for spin-1/2 nucleons, to quark and gluon distribution functions in higher-spin systems. Expressing the antiparton-hadron scattering amplitudes in terms of the PDFs and the spin density matrix, we establish the connections between the PDFs and the scattering amplitudes in the tensor product space of the parton and hadron spins. Moreover, we obtain the definitions of the PDFs in terms of the helicity amplitudes. Positive definiteness of the scattering amplitude matrix yields a set of inequalities that define the physically allowed parameter space for the helicity amplitudes and a set of constraints for the PDFs. The Cauchy-Schwartz inequality determines the constrains between the PDFs and generalized parton distributions.

   hep-phhep-exhep-latnucl-exPRD(2026)·1 citation
8. 08*

   Associated Production of Charmonia-Bottomonia with Color-Octet Channels at the Z Factory, CEPC and FCC-ee

   Xiao-Peng Wang🇨🇳 · Yi-Jie Li🇨🇳 · Guang-Zhi Xu🇨🇳 · Kui-Yong Liu🇨🇳

   Within the nonrelativistic QCD (NRQCD) framework, we investigate the associated production of charmonia+bottomonia at future super $Z$ factory and at the CEPC/FCC-ee. The color-octet(CO) channels in the ${\gamma }^{\ast }/Z^0$-propagated process are considered besides the color-singlet(CS) channels. We find that the contributions of the CO states to the total cross section are dominant for almost all processes from the production threshold to the $Z^0$ mass. Thus, the comparison between the theoretical results and future data may give constraints to the CO matrix elements. In addition, we calculate the relativistic corrections to both the CS and CO channels, which decrease the cross sections significantly, with the $K$ factor $\simeq 0.5$. The predicted events of ($J/\psi +{\rm Y}$, ${\rm Y}+{\eta }_c$) production, with $J/\psi ,{\rm Y}$ reconstructed by lepton pair and ${\eta }_c$ reconstructed by hadronic decays, are (1,1) and (13,10) at the CEPC(2-yr) and FCC-ee(4-yr), respectively.

   hep-phPRD(2026)·1 citation
9. 09*

   QCD matter at a finite magnetic field and nonzero chemical potential

   Zhi-Ying Qin🇨🇳 · Bo Feng🇨🇳 · Ya-Hui Hou🇨🇳 · Hong-Yue Song🇨🇳 · Wen-Chao Zhang🇨🇳 · Hua Zheng🇨🇳 · Shi-Jun Mao🇨🇳

   We construct a hybrid equation of state (EoS) by smoothly interpolating the EoS in the hadron resonance gas at low temperatures to that in the ideal parton gas at high temperatures, and employ it to study the properties of the quantum chromodynamics (QCD) matter under finite magnetic field and nonzero chemical potential. In this work, we neglect the anomalous magnetic moment effects of both charged and neutral particles. Our results show that the thermodynamic observables such as the entropy density, the pressure, the energy density, the trace anomaly, and the specific heat at constant volume are sensitive to both finite magnetic field and chemical potential. As the chemical potential increases from zero, these quantities rise in both the hadronic and quark-gluon plasma phases. In contrast, introducing a magnetic field suppresses them at low temperatures but enhances them at high temperatures. Furthermore, nonzero chemical potential and magnetic field introduce nontrivial modifications to the squared speed of sound. Both effects increase its value near the critical temperature while reducing it at lower temperatures. When both the chemical potential and the magnetic field are present, their influences superimpose, leading to more intricate changes in the thermodynamic behavior. Finally, we compare our results with the lattice QCD data for the quadratic fluctuations of conserved charges and their correlations. The model successfully reproduces the temperature dependence of these observables at $eB=0$ and 0.04 GeV${}^2$. However, at the stronger field strength $eB=0.14$ GeV${}^2$, the model underestimates the magnitudes while still capturing the overall temperature trend.

   hep-phnucl-thPRD(2026)·2 citations
10. 10*

    Spectrum of $[cq][\bar{s}\bar{q}]$ tetraquarks: Nature of $D_{s0}^{\ast }(2317)$, $D_{s1}(2460)$ and $T_{c\bar{s}0}^{\ast }(2900)$

    Zhi-Yuan Chen🇨🇳 · Zhe-Hao Cao🇨🇳 · You-You Lin🇨🇳 · Ji-Ying Wang🇨🇳 · Ailin Zhang🇨🇳

    Motivated by the recent observations of exotic open-charm tetraquark candidates \(T^a_{c\bar{s}0}(2900)^{++}\) and \(T^a_{c\bar{s}0}(2900)^{0}\), we systematically calculate the mass spectra of \([cq][\bar{s}\bar{q}]\) tetraquarks within a nonrelativistic constituent quark potential model. In the model, the tetraquark states are treated as diquark-antidiquark bound systems with an interior interaction similar to the quark-antiquark interaction in conventional mesons. The well established states \(D_{s0}^*(2317)\) with \(J^P=0^+\) and \(D_{s1}(2460)\) with \(J^P=1^+\) could be identified as the two ground states of the \([cq][\bar{s}\bar{q}]\) system. \(T^a_{c\bar{s}0}(2900)^{0}\) and \(T^a_{c\bar{s}0}(2900)^{++}\) could be naturally interpreted as radially excited \(0^+\) tetraquark states with different interior components. Their large mass difference may result from their different interior structure instead of an isospin symmetry breaking. Whether \(T^a_{c\bar{s}0}(2900)^{0}\) and \(T^a_{c\bar{s}0}(2900)^{++}\) belong to an isospin triplet deserves further experimental investigation. In addition, there may be another \(0^+\) \([cq][\bar{s}\bar{q}]\) tetraquark state with mass around $2450$ MeV, which is composed of a $cq$ diquark and a $\bar{s}\bar{q}$ antidiquark both with spin-0. In the energy region $2640-2700$ MeV, there may be a $J^P=2^{+}$ \([cq][\bar{s}\bar{q}]\) tetraquark state composed of the $cq$ diquark and the $\bar{s}\bar{q}$ antidiquark both with spin-1.

    hep-ph2 citations
11. 11*

    QCD phase diagram in a magnetic field with baryon and isospin chemical potentials

    Yu Hamada🇩🇪 · Muneto Nitta🇯🇵 · Zebin Qiu🇯🇵

    Based on the chiral perturbation theory at the leading order, we present the phase diagram of low-energy QCD in a magnetic field at finite baryon and isospin chemical potentials. The phase diagram consists of the QCD vacuum, the chiral soliton lattice, the uniform charged pion condensation, an Abrikosov vortex lattice of the charged pions, a baryonic vortex lattice composed of neutral and charged pion vortices with their topological linking number being the baryon number, and a hybrid phase of chiral soliton and vortex lattices, with their intersections carrying the baryon number. While the chiral soliton lattice demands ultra-strong magnetic field $\sim 10^{19}$ G,the intersection phase appears at $\sim 10^{17}$ G, which is more realistic in neutron stars.

    hep-phcond-mat.supr-connucl-th6 citations
12. 12*

    Heavy-to-light Structure Functions at $\mathcal{O}({\alpha }_s^3)$ in QCD

    Long Chen🇨🇳 · Xiang Chen🇨🇭 · Xin Guan🇺🇸 · Yan-Qing Ma🇨🇳

    We present the first complete $\mathcal{O}({\alpha }_s^2)$ and $\mathcal{O}({\alpha }_s^3)$ perturbative QCD corrections to all five heavy-to-light structure functions underlying the triple-differential semi-leptonic decay rates of heavy quarks. This is achieved via a hybrid computational strategy that combines an efficient linear interpolation (with a suitable function basis) based on stratified Gauss-Kronrod points in the leptonic-mass $q^2$ with the differential equations in the other variable, further armed with reduced numerical $\epsilon$-dependence. Among the selected applications, we highlight the state-of-the-art prediction $\Gamma (B\to X_u\ell {\bar{\nu }}_{\ell })=\frac{|V_{ub}{|}^2}{|3.82\times 10^{-3}{|}^2}(6.53\pm 0.12\pm 0.13\pm 0.03)\times 10^{-16}\text{GeV}$ derived in the kinetic-mass scheme. We report several notable observations regarding the convergence of the first three orders of QCD corrections to the $q^2$-spectrum and to inclusive moments of the lepton-energy spectrum in semi-leptonic weak decays of $b$- and $c$-quark in different quark-mass schemes; they are important both for improving the inclusive determinations of the relevant CKM elements, non-perturbative dynamical parameters, and for gaining new insights into the potential impact of high-order QCD corrections. Lastly we discuss a novel interesting point encountered in the consistent perturbative reformulation of the differential $q^2$-spectrum from the pole-mass to other mass schemes: certain boundary-effect terms are identified that are non-vanishing for $b\to u\ell {\bar{\nu }}_{\ell }$ firstly at $\mathcal{O}({\alpha }_s^3)$; their incorporation is essential to preserve the integrity of the integrated moments of the perturbatively re-expanded $q^2$-spectrum but necessitates histogramming from $\mathcal{O}({\alpha }_s^3)$ onward even within pure perturbation theory.

    hep-phhep-ex3 citations
13. 13*

    Full Three-Loop Electroweak Multiplet Contributions to the Electron Electric Dipole Moment

    Tatsuya Banno🇯🇵 · Junji Hisano🇯🇵 · Teppei Kitahara🇯🇵 · Kiyoto Ogawa🇯🇵 · Naohiro Osamura🇯🇵

    Experimental sensitivity to the electric dipole moment (EDM) of the electron has improved remarkably in recent years. Consequently, future prospects could probe new physics whose contribution to the electron EDM first arises at three-loop order. Additional SU(2)${}_L$ multiplets with CP-violating Yukawa interactions, which contribute to the electron EDM at three-loop level, is one such testable new physics scenario. In this scenario, the electron EDM is radiatively induced from two contributions: the CP-odd trilinear $W$-boson coupling, called the electroweak-Weinberg operator, and the CP-odd dipole operator of electron. The former and the latter operators are generated at two-loop and three-loop levels, respectively, after integrating out the SU(2)${}_L$ multiplets. Within the same models, according to an analysis based on the Standard Model Effective Field Theory (SMEFT), we previously found that the contribution to the electron EDM from the electroweak-Weinberg operator can be probed in future experiments. However, the one-loop matching condition between the electron EDM and the electroweak-Weinberg operator does not receive a large logarithmic enhancement because the associated anomalous dimension is zero. The CP-odd dipole operator of the electron would contribute to the electron EDM at the same three-loop order as the contribution through the electroweak-Weinberg operator. In this paper, we directly calculate the electron EDM induced by the CP-violating Yukawa interactions of the SU(2)${}_L$ multiplets at full three-loop level. A central result is that the full three-loop calculation is a factor of three larger than that of the electroweak-Weinberg operator alone.

    hep-phJHEP(2026)·2 citations
14. 14*

    Recent progress in decays of $b$ and $c$ hadrons

    Aoife Bharucha🇫🇷

    In the last ten years there has been great progress in calculations of decays of $B$ and $D$ mesons, and baryons containing a heavy $b$ or $c$ quark. One propelling factor has been the measurement of several anomalies in $b\to s$ and $b\to c$ transitions, these are one of the only signs of physics beyond the Standard Model. The deviations included measurements of branching ratios, angular observables and lepton universality ratios. Another factor is the exclusive-inclusive discrepancy in the determination of the CKM elements $V_{ub}$ and $V_{cb}$. We will first review recent calculations involving $b\to s$ and $c\to u$ transitions that could shed light on the neutral current anomalies. We will then summarise the progress the determination of the CKM elements, $V_{ub}$ and $V_{cb}$. Finally we will discuss the current theoretical status and experimental prospects for the lepton universality ratios in $b\to s$ and $b\to c$ semileptonic decays.

    hep-phIndian J.Phys.(2023)·1 citation
15. 15*

    Existence of the $D{D}^{\ast }{\bar{K}}^{\ast }$ and $B{B}^{\ast }{K}^{\ast }$ three-body molecular states

    Yan-Ke Chen🇨🇳 · Lu Meng🇨🇳 · Jun-Zhang Wang🇨🇳 · Shi-Lin Zhu🇨🇳

    We investigate the existence of the three-body molecular state composed of $D{D}^{\ast }{\bar{K}}^{\ast }$ within the one-boson-exchange (OBE) model. A major challenge is that while the pseudoscalar-meson couplings are well-determined, the couplings for scalar- and vector-meson exchanges render significant model dependence. To ensure the reliability of our predictions and reduce model dependence, we recalibrate the coupling constants of the OBE model. We treat the pole position of $Z_c(3900)$, or equivalently the scalar $\sigma$-exchange coupling constant, as the only unknown parameter. The coupling constants for the vector $\rho$- and $\omega$-exchanges are determined by the pole positions of the well established states $X(3872)$ and $T_{cc}(3875)$. We demonstrate that these parameter sets also successfully describe the $T_{cs0}(2870)$ without further tuning. For the three-body system, our results indicate that an $I\left(J^P\right)=1/2\left(0^{-}\right)$ three-body molecular bound state exists when $Z_c(3900)$ is a virtual state located within approximately $-10\text{MeV}$ of the $D{\bar{D}}^{\ast }$ threshold. Furthermore, we extend our analysis to the complex energy plane using the complex scaling method to search for molecular resonances, though no evidence of resonances is found in considered channels. We also apply this formalism to the bottom analog $B{B}^{\ast }{K}^{\ast }$ system. In this sector, the conditions for the existence of a three-body bound state are more relaxed, as a $Z_c(3900)$ virtual state located within $-25\text{MeV}$ below the threshold suffices, although three-body molecular resonances remain absent. We suggest that future experiments precisely measure the pole position of $Z_c(3900)$ or search for the three-body bound state in $DD\bar{K}\pi \pi$ and $DD\bar{K}$ channels, as these efforts would mutually illuminate the nature of the associated states.

    hep-phhep-exPRD(2026)·2 citations
16. 16*

    Studies of low energy $l+p\to l+p+\gamma$ process in covariant chiral perturbation theory

    Xu Wang🇨🇳 · Kai-Ge Kang🇨🇳 · Zhiguang Xiao🇨🇳 · Han-Qing Zheng🇨🇳

    This study presents a tree-level calculation of the scattering amplitude for the $lp\to lp\gamma$ (with a hard photon) process within the framework of Chiral Perturbation Theory. Our calculations, based on the $O(p^2)$ and $O(p^3)$ nucleon-pion Lagrangians, aim to provide a theoretical prediction for the differential cross-section. The result shows that explicit inclusion of the nonzero lepton mass significantly influences the low energy differential cross section for $\mu p\to \mu p\gamma$ process. The kinematic region of the present experimental data is beyond the validity domain of the $\chi$PT and is therefore not suitable for determining the low-energy constants (LECs). By comparing our results with future experimental data, we expect to determine the values of the LECs as a further test of $\chi$PT as an effective low-energy theory of QCD. The process is of significant interest as it can help to determine the generalized polarizabilities of the nucleon.

    hep-phhep-exnucl-th0 citations
17. 17*

    Resonating group method for baryon-baryon interactions with unequal oscillator frequencies and its application to the $N\Delta$ system in a chiral quark model

    Ke-Rang Song🇨🇳 · Fei Huang🇨🇳

    The resonating group method (RGM) is widely used to investigate baryon-baryon interactions at the quark level, typically under the assumption that the two baryons involved share an identical harmonic-oscillator frequency. In reality, however, when a specific interaction Hamiltonian is given, different baryons should have unequal oscillator frequencies due to distinct interaction potentials induced by their different quantum numbers. In this work, we develop a new quark-level RGM formalism for baryon-baryon systems with unequal oscillator frequencies, with the aim of providing a unified and consistent framework for describing both single-baryon properties and baryon-baryon interactions. We present the formalism for solving bound-state and scattering problems, with particular emphasis on constructing the wave functions of two-baryon systems with unequal oscillator frequencies. The proposed formalism is then applied to the $N\Delta$ system within a chiral SU(3) quark model, where the quark-quark interaction includes, in addition to the one-gluon exchange (OGE) and a phenomenological confinement potential, the nonet scalar and pseudoscalar meson exchanges arising from the spontaneous breaking of chiral SU(3) symmetry. The distinctive features of the newly developed formalism are demonstrated by comparing the results from the new formulation with those from traditional calculations.

    hep-phnucl-thPRD(2026)·0 citations
18. 18*

    Resurrecting Kaluza-Klein Dark Matter with Low-Temperature Reheating

    Kirtiman Ghosh🇮🇳 · Abhishek Roy🇰🇷 · Rameswar Sahu🇮🇳

    In Universal Extra Dimension (UED) scenarios, the lightest Kaluza-Klein (KK) particle is naturally stable due to a remnant discrete symmetry, KK parity, arising from extra-dimensional compactification. This stability requires no ad hoc symmetry and renders Kaluza-Klein dark matter a well-motivated candidate, provided it reproduces the observed relic abundance. The minimal UED (mUED) framework being highly predictive is strongly constrained by the combined requirements of relic density and collider searches under standard cosmological assumptions. We revisit the dark matter phenomenology of mUED in the presence of a nonstandard cosmological history featuring a low reheating temperature driven by prolonged inflaton decay. Solving the coupled Boltzmann equations for dark matter, radiation, and inflaton energy densities, we show that entropy injection during reheating can dilute the relic abundance by orders of magnitude, reopening large regions of parameter space previously ruled out. We further demonstrate that the revived parameter space is consistent with current collider, direct-detection, and indirect-detection constraints, while remaining testable by upcoming experiments.

    hep-phhep-ex0 citations
19. 19*

    Time-Structured Tail Probabilities for Ultra-High-Energy Gamma-Hadron Discrimination in Water-Cherenkov Arrays

    Ruben Conceição🇵🇹 · Pedro J. Costa🇵🇹 · Mário Pimenta🇵🇹

    Gamma-hadron discrimination based on shower observables is essential for identifying gamma-ray astrophysical sources at the highest energies. In this work, we introduce $P_{\mathrm{tail}}^{\alpha ,T}$, a new discrimination variable for ultra-high-energy photon searches within the framework of a water-Cherenkov detector (WCD) array. The observable extends signal-integrated methods by incorporating the time structure of WCD traces, using cumulative signal distributions. Using simulated proton- and gamma-induced air showers at energies around $10^{17}\mathrm{eV}$, we evaluate the performance of $P_{\mathrm{tail}}^{\alpha ,T}$ and compare it with established WCD-based observables such as $S_b$, risetime-based variables, and the SWGO-inspired, $P_{\mathrm{tail}}^{\alpha }$. The new variable attains a background contamination of roughly $2\times 10^{-2}$ at $50\%$ gamma efficiency, improving upon existing WCD-only methods by nearly a factor of five and approaching the performance of an idealized muon-isolating reference. These results demonstrate the effectiveness of exploiting time-resolved signal tails to enhance ultra-high-energy photon searches in sparse surface arrays.

    hep-phhep-ex0 citations
20. 20*

    Systematic Operator Construction for Non-relativistic Effective Field Theories: Hilbert Series versus Young Tensor

    Yong-Kang Li🇨🇳 · Yi-Ning Wang🇨🇳 · Jiang-Hao Yu🇨🇳

    This work establishes a systematic framework for operator construction in the non-relativistic effective field theory, incorporating both the three dimensional Euclidean symmetry and the internal symmetries. By employing double cover of the rotation group, we extend the Hilbert series to the non-relativistic systems, and eliminates redundancies introduced by the spin operator. We also generalize the Young tensor method to the non-relativistic cases through the $SU(2)$ semi-standard Young tableaux, which allows for the construction of operator bases with repeated fields at any given mass dimension. Utilizing the Young tensor technique and Hibert series as cross-check, we obtain the complete operator bases for the following cases: heavy particle (and also heavy quark) effective theory operators up to mass dimension 9; pion-less effective theory operators, including nucleon-nucleon contact interactions up to $\mathcal{O}(Q^4)$ and three-nucleon interactions at $\mathcal{O}(Q^2)$; and finally the spin-1/2 dark matter-nucleon operators up to $\mathcal{O}(v^4)$.

    hep-phnucl-th1 citation
21. 21*

    Higgs decays to four leptons to $\mathcal{O}(1/{\Lambda }^4)$ in SMEFT

    Mario Flores-Hernandez🇺🇸 · Adam Martin🇺🇸

    We study the decays $h\to \ell \bar{\ell }\left(Z\to {\ell }^{\prime }\overline{{\ell }^{\prime }}\right)$ and $h\to \ell {\bar{\nu }}_{\ell }{\nu }_{{\ell }^{\prime }}\overline{{\ell }^{\prime }}$ within the SMEFT framework and including effects up to $\mathcal{O}(1/{\Lambda }^4)$, where $\Lambda$ is the new physics scale suppressing higher dimensional operators. To work to this order, we must include the square of dimension-six operators and the interference of dimension-eight operators with the Standard Model. We study angular asymmetries and other differential decay observables and determine which are most sensitive to $\mathcal{O}(1/{\Lambda }^4)$ effects. While new kinematic structures arising in higher dimensional operators have the potential to induce novel angular dependency, we find this does not occur for $h\to \ell \bar{\ell }\left(Z\to {\ell }^{\prime }\overline{{\ell }^{\prime }}\right)$. For $h\to \ell {\bar{\nu }}_{\ell }{\nu }_{{\ell }^{\prime }}\overline{{\ell }^{\prime }}$, new angular dependencies do arise at $\mathcal{O}(1/{\Lambda }^4)$, though they require a fully reconstructible (meaning we can go to the Higgs rest frame) final state. For non-reconstructible final states such as $\ell {\bar{\nu }}_{\ell }{\nu }_{{\ell }^{\prime }}\overline{{\ell }^{\prime }}$, we must study Higgs production and decay together with the appropriate observables, which we find obscures the new angular effects.

    hep-phJHEP(2026)·3 citations
22. 22*

    Producing $\Lambda (1405)$ and $\Lambda (1520)$ in ${\pi }^{-}p$ reaction to explore their inner structures

    Yuan Gao🇨🇳 · Xiao-Yun Wang🇨🇳 · Xiang Liu🇨🇳

    In this work, the production mechanisms of the hyperon resonances $\Lambda (1405)$ and $\Lambda (1520)$ in the ${\pi }^{-}p$ scattering are investigated within an effective Lagrangian approach incorporating Regge trajectories. By including contributions from $t$-channel $K^{\ast }$ and $u$-channel $\Sigma$ exchanges, we perform global fits to the total and differential cross sections for ${\pi }^{-}p\to K\Lambda (1405)$ and ${\pi }^{-}p\to K\Lambda (1520)$. The results show good agreement with available experimental data. For the total cross section of $\Lambda (1405)$ production, the $u$-channel contribution is dominant, whereas the $t$-channel contribution plays the primary role in $\Lambda (1520)$ production. Furthermore, the differential cross sections of the two processes exhibit distinctly different shapes, reflecting their distinct underlying reaction mechanisms. An analysis based on the constituent counting rule indicates that $\Lambda (1520)$ is consistent with a conventional three-quark configuration, while $\Lambda (1405)$ shows a clear deviation, suggesting a more exotic structure. Owing to the large branching ratio of ${\Lambda }^{\ast }\to \pi \Sigma$, the Dalitz process ${\pi }^{-}p\to K{\Lambda }^{\ast }\to K\pi \Sigma$ is also calculated. Our results demonstrate that reconstructing ${\Lambda }^{\ast }$ via the $K\pi \Sigma$ final state is experimentally feasible. This study provides important theoretical insights into the production dynamics of these hyperon resonances, and suggests future high-precision measurements of the $t$-distribution at large momentum transfer at facilities such as AMBER, J-PARC, HIKE, and HIAF, which can further clarify their reaction mechanisms and structural properties.

    ↳ nucl-thhep-phhep-thPRD(2026)·3 citations
23. 23*

    Numerical simulation of the stochastic formalism including non-Markovianity

    Masahiro Kawasaki🇯🇵 · Tomotaka Kuroda🇯🇵

    We numerically investigate stochastic dynamics in cosmology by solving Langevin equations for Infrared (IR) modes with stochastic noises generated by Ultraviolet (UV) modes at the coarse-graining scale. By construction, the stochastic formalism relies on the separation of scales, which requires solving the equations for UV modes on top of the evolving IR modes for all modes at every time step, leading to a non-Markovian system in general. In this paper, working on a de Sitter background, we analyze several representative models by simultaneously solving the Langevin equations for IR modes and the equations for UV modes at each time step. We demonstrate that once the effects of effective masses are treated consistently by our simulation, the flat direction in the minimal supersymmtric model (MSSM) does not saturate but instead evolves as an exactly flat direction. Furthermore, we investigate memory effects in simple two models; $V=\lambda {\varphi }^4$ and $V=\mu \varphi \chi +\lambda {\varphi }^4$, and non-Markovian contributions can lead to quantitative differences, even in stationary configurations, when compared with Markovian approximations, particularly in the strong-coupling regime.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2026)·7 citations
24. 24*

    GR from RG: Gravity Is Induced From Renormalization Group Flow In The Infrared

    M.M. Sheikh-Jabbari🇮🇷 · V. Taghiloo🇮🇷

    In this essay and utilizing the holographic Renormalization Group (RG) flow, we demonstrate how the effective action of a non-gravitating quantum field theory in the ultraviolet (UV) develops an Einstein-Hilbert term in the infrared (IR). That is, gravity is induced by the RG flow. An inherent outcome of holography that plays a crucial role in our analysis is the \textit{RG flow of boundary conditions}: the rigid Dirichlet conditions on the background metric in the UV become an admixture of Dirichlet and Neumann as we flow to the IR, thereby ``unfreezing'' the metric and transforming it from a non-dynamical background into a dynamical field. This mechanism, which is a conceptually new addition to the standard Wilsonian RG flow, also provides the mechanism to evade the Weinberg-Witten no-go theorem. Within the GR from RG picture outlined here, the search for a quantum theory of gravity by treating the metric as a fundamental field may be a hunt for a phantom--akin to seeking the atomic structure of water by quantizing the equations of hydrodynamics.

    ↳ hep-thastro-ph.COgr-qchep-ph1 citation
25. 25*

    Cosmographic Connection Between Cosmological And Planck Scales: The Barrow-Tsallis Entropy

    Yu. L. Bolotin🇺🇦 · V.V. Yanovsky🇺🇦 · D. A. Yerokhin

    One of the fundamental challenges of quantum gravity is to understand how the microscopic degrees of freedom of the cosmological horizon shape the evolution of the Universe. One possible approach to this problem is based on the Barrow--Tsallis entropy. This entropy accounts for both quantum gravitational effects and the nonextensive effects inherent in any long-range interaction. By employing an inverse cosmographic reconstruction of the model parameters, we derive a relation between the Barrow parameter, which encodes the microscopic deformation of the horizon geometry, and the Tsallis parameter, which characterizes macroscopic nonextensivity. Within the IR--UV correspondence, this relation determines the scaling of the microscopic length uncertainty in terms of the current cosmographic parameters and demonstrates how long-range nonextensive effects alter the standard Karolyhazy-type scaling. We also applied our cosmographic reconstruction method to evaluate the feasibility of using fractional derivatives to describe the late evolution of the Universe. Within the assumed non-interacting power-law holographic model class, the resulting algebraic relations are exact. For this fixed model class, the observational uncertainty of the reconstructed parameter combination is determined by the current uncertainties in the cosmographic parameters; the quoted uncertainty of $\delta$ additionally includes the adopted prior on $\Delta$, but not uncertainty associated with the model choice. Propagating the observational errors of the deceleration and jerk parameters and marginalizing over a uniform prior on the Barrow parameter within the adopted interval $\Delta \in [-1,1]$, we obtain the Monte Carlo estimate $\delta =1.11\pm 0.57$ for the nonextensivity parameter, with the jerk parameter providing the largest observational contribution to the error budget.

    ↳ gr-qcastro-ph.COhep-phhep-th2 citations
26. 26*

    Elliptic flow of strange and multi-strange hadrons in isobar collisions at $\sqrt{s_{\mathrm{NN}}}=200\mathrm{GeV}$ at RHIC

    The STAR Collaboration

    We report a systematic measurement of elliptic flow ($v_2$) of $K_s^0$, $\Lambda$, $\overline{\Lambda }$, $\varphi$, ${\Xi }^{-}$, ${\overline{\Xi }}^{+}$, and ${\Omega }^{-}$+${\overline{\Omega }}^{+}$ at mid-rapidity ($|y|<1.0$) for isobar, ${}_{44}^{96}$Ru+${}_{44}^{96}$Ru and ${}_{40}^{96}$Zr+${}_{40}^{96}$Zr, collisions at $\sqrt{s_{\mathrm{NN}}}$ = 200 GeV. The transverse momentum ($p_{\mathrm{T}}$) dependence of $v_2$ is studied for various centrality classes. The number of constituent quark scaling of (multi-)strange hadrons is found to hold approximately within 20%, suggesting the development of partonic collectivity in isobar collisions similar to that observed in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 200 GeV. The average $v_2$ ratio shows $\sim$2% deviation from unity in central and mid-central collisions for strange hadrons, indicating a difference in nuclear structure and deformation between the isobars. The $v_2$ in isobaric collisions is compared to Cu+Cu, Au+Au, and U+U collisions at similar collision energies. We observe an increase in $v_2(p_{\mathrm{T}})$ with increasing system size. The difference in $v_2$ between the isobar and other collision systems increases with $p_{\mathrm{T}}$. The results are compared with a multi-phase transport model calculations with a deformed density profile to provide further insight into the nuclear structure of these isobars.

    ↳ nucl-exhep-exhep-phnucl-th1 citation
27. 27*

    Black Holes Trapped by Ghosts

    Cheng-Yong Zhang🇨🇳 · Yunqi Liu🇨🇳 · Bin Wang🇨🇳

    Violent cosmic events, from black hole mergers to stellar collapses, often leave behind highly excited black hole remnants that inevitably relax to equilibrium. The prevailing view, developed over decades, holds that this relaxation is rapidly filtered into a linear regime, establishing linear perturbation theory as the bedrock of black hole spectroscopy and a key pillar of gravitational-wave physics. Here we unveil a distinct nonlinear regime that transcends the traditional paradigm: before the familiar linear ringdown, an intrinsically nonlinear, long-lived bottleneck can dominate the evolution. This stage is controlled by a saddle-node ghost in phase space, which traps the remnant and delays the onset of linearity by a timescale obeying a universal power-law. The ghost imprints a distinctive quiescence-burst signature on the emitted radiation: a prolonged silence followed by a violent burst and a delayed ringdown. Rooted in the bifurcation topology, it extends naturally to neutron and boson stars, echoing a topological universality shared with diverse nonlinear systems in nature. Our results expose a missing nonlinear chapter in gravitational dynamics and identify ghost-induced quiescence-burst patterns as clear targets for future observations.

    ↳ gr-qchep-ph0 citations
28. 28*

    Single-minus gluon tree amplitudes are nonzero

    Alfredo Guevara🇺🇸 · Alexandru Lupsasca🇺🇸 · David Skinner🇬🇧 · Andrew Strominger🇺🇸 · Kevin Weil🇺🇸

    Single-minus tree-level $n$-gluon scattering amplitudes are reconsidered. Often presumed to vanish, they are shown here to be nonvanishing for certain "half-collinear" configurations existing in Klein space or for complexified momenta. We derive a piecewise-constant closed-form expression for the decay of a single minus-helicity gluon into $n-1$ plus-helicity gluons as a function of their momenta. This formula nontrivially satisfies multiple consistency conditions including Weinberg's soft theorem.

    ↳ hep-thhep-ph34 citations
29. 29*

    Extending the Cosmological Collider: New Scaling Regimes and Constraints from BOSS

    Daniel Green🇺🇸 · Jiashu Han🇺🇸 · Benjamin Wallisch🇸🇪

    Primordial non-Gaussianity generated by additional fields during inflation offers a compelling observational target. Heavy fields imprint characteristic oscillatory signals in non-Gaussian correlation functions of the inflaton, a process sometimes referred to as cosmological-collider physics. These distinct signatures are compelling windows into ultra-high-energy physics, but are often suppressed, making standard equilateral non-Gaussianity the most promising discovery channel in many scenarios. In this paper, we show that direct couplings between the inflaton and additional fields can lead to a wide variety of novel, observationally relevant signals which open new parameter regimes that simultaneously exhibit the characteristics of light and heavy fields. We identify these primordial signatures in the late-time observables of the large-scale structure of the Universe, where they most significantly modify the scale-dependent bias of the galaxy power spectrum to include an oscillatory modulation around a non-trivial power law. We explore the full range of parameters that phenomenologically arise in these models and study the sensitivity of current and future galaxy surveys, finding that this new class of primordial non-Gaussianity is particularly accessible in near-term surveys due to its oscillatory feature. Finally, we perform an analysis of existing data from the final release of the Baryon Oscillation Spectroscopic Survey (BOSS DR12). While we find no evidence for a signal, we demonstrate significant improvements in sensitivity over respective non-oscillatory scenarios and place the first constraints on this extended parameter space of oscillatory non-Gaussianity.

    ↳ astro-ph.COhep-phhep-th15 citations
30. 30*

    The Dark Side of the Moon: Listening to Scalar-Induced Gravitational Waves

    D. Blas🇪🇸 · J. W. Foster🇺🇸 · Y. Gouttenoire🇩🇪 · A. J. Iovino🇦🇪 · I. Musco🇸🇮 · S. Trifinopoulos🇨🇭 · M. Vanvlasselaer🇪🇸

    The collapse of large-amplitude primordial curvature perturbations into planetary-mass primordial black holes generates a scalar-induced gravitational wave background in the $\mu$Hz frequency range that may be detectable by future Lunar Laser Ranging and Satellite Laser Ranging data. We derive projected constraints on the primordial black hole population from a null detection of stochastic gravitational wave background by these experiments, including the impact of the standard model electroweak phase transition on the abundance of planetary-mass primordial black holes. We also discuss the connection between the obtained projected constraints and the recent microlensing observations by the HSC collaboration of the Andromeda Galaxy.

    ↳ astro-ph.COgr-qchep-phPLB(2026)·12 citations
31. 31*

    Symmetric Gapped States and Symmetry-Enforced Gaplessness in 3-dimension

    Arun Debray🇺🇸 · Matthew Yu🇬🇧 · Weicheng Ye🇨🇦

    We establish a comprehensive framework for characterizing the infrared (IR) phases of a fermionic quantum theory in three spatial dimensions, based on its quantum anomalies associated with a finite symmetry. We uncover a fundamental dichotomy among these anomalies: the first class of anomalies can always be realized by symmetric gapped states, while the second class can never be realized by gapped states without breaking the given symmetry, establishing the phenomenon of symmetry-enforced gaplessness in these settings. Moreover, using the construction of symmetry extension, we construct the candidate gapped states that theories with the first class of anomalies can flow to in the IR. As an application, we provide concrete predictions of the candidate IR phases of (3+1)-dimensional gauge theories based on our results. Our results also suggest that systems with discrete chiral anomalies cannot be gapped out by adding arbitrary bosonic degrees of freedom.

    ↳ hep-thcond-mat.str-elhep-phmath-ph+16 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.