Wed·Feb 4, 2026Wednesday·February 4, 2026

1. 01*

   Exploring Thermalization and Multi-Freeze-Out Effects in Pb-Pb collisions Based on Tsallis pT Distributions

   Haifa I. Alrebdi🇸🇦 · Muhammad Ajaz🇵🇰 · Murad Badshah🇵🇰 · Mohammad Ayaz Ahmad🇬🇾

   This study investigates transverse-momentum (pT) distributions of pi-, pi+, K-, K+, p, pbar, K0s, and Lambda in several centrality classes of Pb-Pb collisions at sqrt(sNN) = 2.76 TeV. The measured spectra are analyzed with the Tsallis non-extensive distribution, from which the effective temperature T, non-extensive parameter q, and the mean transverse momentum mean_pT are extracted for each particle species and centrality interval. To disentangle thermal and collective effects, the mean kinetic freeze-out temperature T0 is obtained from the intercept of the T-versus-mass relation, while the average transverse flow velocity betaT is extracted from the slope of mean_pT versus the mean moving mass for pions, kaons, and protons. The results show that T increases and q decreases with increasing centrality, indicating a hotter and more equilibrated system in central collisions. A clear mass dependence of T supports a multi-freeze-out scenario, with heavier particles decoupling earlier. Both T0 and betaT rise from peripheral to mid-central collisions before saturating toward central events, which may suggest the onset of collective behavior or changes in freeze-out dynamics. These observations provide new insights into the thermal and dynamical properties of the medium created in heavy-ion collisions at the LHC.

   hep-phnucl-exnucl-thCPC(2026)·5 citations
2. 02*

   Generalized Neutrino Interactions: constraints and parametrizations

   L. J. Flores🇲🇽 · O. G. Miranda🇲🇽 · G. Sanchez Garcia🇲🇽

   Generalized neutrino interactions (GNI) are emerging as a convenient framework for describing effective scalar, vector, and tensor interactions. Such interactions arise naturally from extensions of the Standard Model that aim to explain neutrino properties and their mass origin. In this paper, we carefully study the two more common parametrizations for GNI and how to relate them. This allows us to compare bounds obtained from CEvNS and deep-inelastic scattering under the same footing. In addition, we present the current bounds from CEvNS measurements by COHERENT and compare them to those obtained from deep inelastic scattering on the same level. Our results focus on neutrino-quark interactions, and illustrate the complementarity between experiments working at different scales for GNI, showing that scalar interactions are better constrained by low-energy experiments like COHERENT, while tensor interactions are robustly constrained from deep inelastic scattering.

   hep-phhep-exPRD(2026)·2 citations
3. 03*

   Hydrogenated carbon structures as directional sub-GeV dark matter detectors

   Tomás Arias🇺🇸 · Antonino Bellinvia🇮🇹 · Gianluca Cavoto🇮🇹 · Angelo Esposito🇮🇹 · Francesco Pandolfi🇮🇹 · Guglielmo Papiri🇺🇸 · Antonio D. Polosa🇮🇹 · Tyler Wu🇺🇸

   We propose hydrogenated carbon structures as targets with a remarkable sensitivity to dark matter-nucleon interactions, in the mass range between the 1 MeV and 100 MeV. The ejection of a proton following the interaction with a dark matter particle is a quasi-elastic process, with an extremely small energy threshold, and a clear experimental signature. The proposed detectors are simple, technologically ready, and inexpensive. Yet, they can be considerably more sensitive than current experiments. They also allow strong directionality, to be used towards efficient background rejection.

   hep-phhep-exPRD(2026)·0 citations
4. 04*

   Quantum Tomography of Fermion Pairs in $e^{+}{e}^{-}$ Collisions: Longitudinal Beam Polarization Effects

   Yu-Chen Guo🇨🇳 · Tao Han🇺🇸 · Matthew Low🇺🇸 · Youle Su🇺🇸

   We present a quantum tomography study of fermion pair production at future $e^{+}{e}^{-}$ colliders, emphasizing how longitudinal beam polarization controls the two-qubit spin density matrix. We study the processes $e^{+}{e}^{-}\to t\bar{t},e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}$ and Bhabha scattering $e^{+}{e}^{-}\to e^{+}{e}^{-}$, representing the mass threshold behavior, the $Z$ pole resonance and the $s/t$-channel interplay. We choose to focus on three key concepts: quantum entanglement via the concurrence $\mathcal{C}$, Bell nonlocality via the optimal Clauser Horne Shimony Holt (CHSH) parameter $\mathcal{B}$, and non-stabilizerness (``magic'') via the second stabilizer Rényi entropy ${\mathcal{M}}_2$. For the $s$-channel-dominated channels, longitudinal polarization mainly reshapes single-spin polarizations while leaving the spin-correlation matrix largely unchanged, rendering $\mathcal{C}$ and $\mathcal{B}$ comparatively robust, but inducing a pronounced variation of ${\mathcal{M}}_2$. In contrast, in Bhabha scattering, polarization modifies the relative contributions of the $s$-channel and $t$-channel and can strongly affect all three observables. The observability of entanglement, Bell nonlocality, and magic exceeds the $5\sigma$ level when both statistical and systematic uncertainties are included, establishing the fermion pair systems as ideal laboratories for quantum-information studies in high energy leptonic collisions. With optimized beam polarization, future $e^{+}{e}^{-}$ colliders will provide a unique opportunity to experimentally explore and influence quantum resources in particle interactions.

   hep-phquant-ph29 citations
5. 05*

   Differentiating Dimension-6 and Dimension-8 Effects in $\nu$SMEFT at the HL-LHC

   Manimala Mitra🇮🇳 · Shakeel Ur Rahaman🇬🇧 · Subham Saha🇮🇳 · Michael Spannowsky🇬🇧

   We study dimension-eight effects in the Standard Model Effective Field Theory extended by right-handed neutrinos ($\nu$SMEFT). Using the Hilbert series formalism, we derive the complete basis of dimension-eight operators and confirm agreement with existing classifications, providing a systematic framework beyond the conventional dimension-six truncation. We analyse the collider phenomenology of the representative operator ${\mathcal{O}}_{N^2{q}^{2}B}^{(1,2)}$ at the High-Luminosity LHC. The resulting signatures involve pair production of right-handed neutrinos in association with jets, followed by decays into electron-jet final states with potentially displaced vertices. Since similar final states are generated by leading dimension-six operators, we explicitly address whether dimension-eight contributions can be experimentally distinguished from dimension-six effects. Using a Boosted Decision Tree analysis based on kinematic observables, we show that the dimension-eight signal can be reliably separated from each relevant dimension-six hypothesis. Our results demonstrate that dimension-eight operators in the $\nu$SMEFT can give rise to experimentally resolvable signatures and should be included in collider EFT interpretations.

   hep-ph1 citation
6. 06*

   Searching for missing direct photons in heavy-ion collisions with P and CP violation

   Jonathan D. Kroth🇺🇸 · Kirill Tuchin🇺🇸

   We compute synchrotron radiation from a plasma in which $P$- and $CP$-violating parameters, a chiral chemical potential and a chiral gradient, couple to fermions. To do this, we compute exact wavefunctions for the fermions in the presence of these parameters and an external constant magnetic field. We find that these parameters increase the synchrotron radiation emitted by the fermions while also decreasing the traditionally large synchrotron radiation elliptic flow coefficient $v_2$. We apply these results to the quark-gluon plasma, where just such a contribution could provide a solution to the missing direct photons puzzle. We also use our wavefunctions to give a derivation of the chiral magnetic effect.

   hep-phPRD(2026)·3 citations
7. 07*

   Wave packet description of Majorana neutrino oscillations in a magnetic field

   Artem Popov🇷🇺 · Alexander Studenikin🇷🇺 · Alexander Tcvirov

   Majorana neutrino oscillations in a magnetic field are considered using the wave packets formalism. The modified Dirac equation for Majorana neutrinos with non-zero transition magnetic moments propagating in a magnetic field is solved analytically in the two flavour case. The expressions for the oscillations probabilities are derived accounting for the decoherence effect emerging at distances exceeding the coherence length. It is shown that for Majorana neutrinos propagating in a magnetic field the coherence length coincides with the coherence length for neutrino oscillations in vacuum when the vacuum frequency is much greater than the magnetic frequency (${\omega }_{vac}\gg {\omega }_B$), while it is proportional to the cube of the average neutrino momentum if (${\omega }_{vac}\ll {\omega }_B$). We show that the decoherence effect may appear during neutrino propagation in a magnetic field of supernova.

   hep-phhep-thquant-ph0 citations
8. 08*

   Dark Matter-Induced Nuclear De-Excitation at SBND with Ab Initio Nuclear Theory

   Bhaskar Dutta🇺🇸 · Debopam Goswami🇷🇴 · Baishan Hu🇺🇸 · Wei-Chih Huang🇺🇸 · Vishvas Pandey🇺🇸

   We explore the sensitivity of the Short-Baseline Near Detector (SBND) experiment to light dark matter using MeV-scale electromagnetic activity. Inelastic scattering of dark matter with argon nuclei can excite nuclear states that subsequently de-excite via the emission of MeV-scale photons, producing localized low-energy "blip" signatures in a liquid argon time projection chamber. We perform state-of-the-art ab initio nuclear calculations, including all relevant argon excited states with energies up to 18 MeV, to provide reliable predictions for these signals. After accounting for relevant backgrounds, we find that SBND can probe previously unexplored regions of parameter space for light dark matter.

   hep-phhep-exnucl-exnucl-th3 citations
9. 09*

   Cosmological phase transitions: from particle physics to gravitational waves, semi-analytically

   S. Pascoli🇮🇹 · S. Rosauro-Alcaraz🇮🇹 · M. Zandi🇮🇹

   Motivated by the recent evidence of a stochastic gravitational wave background found by pulsar timing array experiments, we focus on one of the prime cosmological explanations, i.e. a supercooled first order phase transition. If confirmed, it would offer a unique opportunity to probe early Universe dynamics and the related physics beyond the Standard Model of particles and interactions. However, the prediction of the gravitational wave spectrum from a given particle physics scenario requires theoretically and computationally demanding methods. While several tools have been put forward to reduce uncertainties and automatize these computations, we study here the possibility to perform the full pipeline of computations semi-analytically in the $4D$ theory for a $U(1{)}^{\prime }$ conformal extension of the Standard Model, thus avoiding computationally intensive simulations. Our approach yields accurate results that can be used in phenomenological studies and allow for an efficient exploration of the connection between the particle physics models and their cosmological predictions.

   hep-phastro-ph.COHiHEP(2026)·7 citations
10. 10*

    Transport Coefficients from pQCD to the Hadron Resonance Gas at finite BSQ densities

    Isabella Danhoni🇺🇸

    We calculate the shear viscosity, $\eta$, in two limits: perturbative QCD and an excluded-volume hadron resonance gas (HRG), at finite BSQ densities. Using an interpolation framework, we connect these regimes. In addition, we present results for (almost) next-to-leading order weak-coupling shear viscosity for QCD at finite ${\mu }_B$, and discuss the convergence of the perturbative series.

    hep-phEPJ Web Conf.(2026)·0 citations
11. 11*

    Contact interaction treatment of the nucleon Faddeev equation

    Xin-Yu Bai🇨🇳 · Ya Lu🇨🇳 · Zhao-Qian Yao🇨🇳 · Craig D. Roberts🇨🇳 · Sebastian M. Schmidt🇩🇪

    Working with a symmetry-preserving treatment of a vector*vector contact interaction (SCI), a largely algebraic three-body Faddeev equation treatment of the nucleon bound state problem is introduced and used to deliver results for all nucleon charge and magnetisation distributions and their flavour separation. A strength of the SCI treatment is that it provides for a transparent understanding of this three-body approach to developing predictions for baryon observables. Comparisons of SCI results with predictions obtained in realistic-interaction Faddeev equation studies reveal the sensitivities of a given observable to the pointwise behaviour of the quark-quark interaction and phenomena associated with the emergence of hadron mass.

    hep-phhep-latnucl-exnucl-thEPJA(2026)·3 citations
12. 12*

    Constraints on light dark matter from primordial black hole evaporation at dark matter direct detection experiments

    Tong Zhu🇨🇳 · Cheng-Rui Jiang🇨🇳 · Tong Li🇨🇳 · Jiajun Liao🇨🇳

    Primordial black holes (PBHs) are able to produce light dark matter (DM) particles via Hawking radiation, and yield a flux of boosted DM that can be probed at underground DM direct detection experiments. We analyze both galactic and extragalactic contributions to the differential flux of light DM from PBH evaporation, and then compute the expected event rate from PBH boosted DM scattering off electrons or nuclei after taking into account the attenuation effect. Using recent data from DM direct detection experiments XENONnT, PandaX-4T and LZ, we set constraints on both DM-electron and DM-nucleus scattering cross sections, as well as the fraction of DM composed of PBHs $f_{\mathrm{PBH}}$ for $9\times 10^{14}-1\times 10^{16}\mathrm{g}$ PBHs that are not fully evaporated today. We also investigate the spectral evolution induced by Hawking evaporation throughout the evaporation and post-evaporation regimes. The constraints on the PBH mass are then extended into the $1\times 10^{13}-6\times 10^{14}\mathrm{g}$ window for fully evaporated PBHs.

    hep-phPRD(2026)·1 citation
13. 13*

    Extraction of the pion-nucleon coupling constant using the effective-range expansion with the left-hand cut

    Bo-Yang Liu🇨🇳 · Bing Wu🇨🇳 · Ji-Wei Fu🇨🇳 · Meng-Lin Du🇨🇳 · Feng-Kun Guo🇨🇳 · Ulf-G. Meißner🇩🇪

    We apply the generalized effective-range expansion of Phys. Rev. Lett. 135, 011903(2025), which incorporates the left-hand cut from one-pion exchange, to low-energy neutron-proton scattering in the ${}^1{S}_0$ and ${}^3{S}_1$ channels. The amplitude zero for the center-of-mass momentum near 0.35 GeV in the ${}^1{S}_0$ channel is naturally accommodated within this framework. We extract the pole position, scattering length, effective range, and the pseudoscalar pion-nucleon coupling constant $g_{\pi N}^2/(4\pi )$ at different expansion orders. The low-energy parameters are stable and consistent with established values, while $g_{\pi N}^2/(4\pi )$ exhibits larger uncertainties. The extraction of $g_{\pi N}^2/(4\pi )$ is data-driven, relying on the analytic constraints from the left-hand cut and phase-shift data within the one-pion-exchange approximation. Despite larger uncertainties compared to high-precision extractions, the consistency with established values demonstrates that this framework can probe the left-hand-cut singularity.

    hep-phnucl-th2 citations
14. 14*

    Studying Energy-Energy Correlators in pp Collisions at the LHC with a Jet-Free Event-Topology Method

    Yazhen Lin · Liang Zheng · Zhongbao Yin

    We present a jet-free approach for measuring energy-energy correlators (EEC) in proton-proton (pp) collisions at the Large Hadron Collider (LHC), employing an event-topology method that does not rely on explicit jet reconstruction. Using the leading charged hadron as a reference axis, the azimuthal plane is divided into Toward and Transverse regions, enabling a robust background subtraction and extending EEC measurements into the low $p_T$ regime where conventional jet-based approaches become unreliable. The method is validated through comparisons with conventional jet reconstruction results. We systematically explore the dependence of the EEC on the leading-particle transverse momentum and parton flavor. The observed scaling between the EEC peak position and the hard scale suggests that this topology-based EEC captures effectively the transition between perturbative and non-perturbative QCD regimes. Distinct differences are found between quark- and gluon-initiated events, reflecting their different color charges and radiation patterns. Extending the analysis to heavy flavor, EECs triggered by leading charm mesons exhibit a suppressed magnitude and a peak shifted toward larger angular separations relative to inclusive charged-particle triggers, providing a direct manifestation of the dead-cone effect. This jet-free EEC framework offers a simple and experimentally robust tool for studying the scale and flavor dependence of the QCD dynamics, with promising applications to proton-nucleus and heavy-ion collisions at the LHC.

    hep-phhep-exEPJC(2026)·0 citations
15. 15*

    Search for the production of dark Higgs in the framework of Mono-Z${}^{\prime }$ portal at the FCC-ee simulated electron-positron collisions at $\sqrt{s}=240$ GeV

    S. Elgammal🇪🇬 · N. De Filippis🇮🇹

    We conducted a Monte Carlo search for dark Higgs particles ($h_D$), which is based on a model derived from the Mono-Z${}^{\prime }$ portal. This model suggests the existence of $h_D$ and a new neutral gauge boson, denoted as Z${}^{\prime }$. Our study focused on the event topology featuring two oppositely charged muons and missing transverse energy, generated from simulations of $e^{+}{e}^{-}$ collisions at the Future Circular Collider (FCC-ee). This collider is set to operate with 240 GeV a center-of-mass energy ($\sqrt{s}$), and will achieve an integrated luminosity of 10.8 ab${}^{-1}$. In our analysis, we estimated upper limits on the mass of the dark Higgs at a 95\% confidence level, assuming that no $h_D$ particles were detected.

    hep-ph1 citation
16. 16*

    Collectivity Signatures in High-Multiplicity pp Collisions from Hybrid Hydro+Tsallis Modeling of Pion Spectra

    Murad Badshah🇵🇰 · Haifa I. Alrebdi🇸🇦 · Muhammad Waqas🇨🇳 · Hadiqa Qadir🇵🇰 · Muhammad Ajaz🇵🇰

    The transverse momentum (pT) distributions up to pT = 20 GeV/c for pions produced in the ten different multiplicity classes (MCs) of symmetric pp collisions at sqrt(s) = 7 TeV have been investigated. Two distinct models, the Tsallis-Pareto type function (model) and the combined BGBW model and Tsallis-Pareto type model have been employed to fit the pT distributions via the minimum chi-square method. The combined Hydro+Tsallis model is more reliably describing the pT spectra than the Tsallis-Pareto model. The Tsallis temperature (T), non-extensivity parameter (q), normalization constant (N0), Kinetic freeze-out temperature (T0), transverse flow velocity (betaT), and (mean pT) have been extracted through the fitting procedure via the employed models. The Tsallis-Pareto model gives T, q, N0 and mean pT while Hydro+Tsallis model gives T0, betaT, T, q, N0 and mean pT. Incorporating the values of the extracted T and q the thermodynamic quantities and response functions, including energy density (epsilon), particle density (n), entropy density (s), pressure (P), specific heat at constant volume (CV), squared speed of sound (cs2), mean free path (lambda), Knudsen number (Kn), isothermal compressibility (kappaT), and expansion coefficient (alpha) have been calculated at the freeze-out stage. It has been observed that T, betaT, mean pT, N0, epsilon, n, s, P, CV, cs2, and alpha increase with increasing(decreasing) the charged particles multiplicity density dNch/deta(MCs). While T0, q, lambda, Kn, and kappaT decrease with increasing(decreasing) dNch/deta(MCs). These systematic variations in the trends of parameters might suggest the gradual transition towards collectivity and thermal equilibration in the high multiplicity pp events, possibly signalling enhanced collective dynamics and partial thermalization in small collision systems.

    hep-phNPA(2026)·1 citation
17. 17*

    Asymmetric dark matter from leptogenesis in type-III seesaw framework with modular $S_4$ symmetry

    Abhishek🇮🇳 · V. Suryanarayana Mummidi🇮🇳

    We present a unified framework for neutrino masses, baryogenesis, and dark matter based on a modular $S_4$ symmetry combined with a type-III seesaw mechanism. All Yukawa couplings, CP phases, and flavor textures originate from a single complex modulus $\tau$, whose vacuum expectation value controls both visible and dark sector dynamics. The same modular parameter fixes the neutrino mass matrix, determines the CP asymmetries driving resonant leptogenesis, and correlates the resulting baryon and dark matter abundances. A detailed numerical analysis shows that the model reproduces all neutrino oscillation data within the $3\sigma$ NuFIT~5.2 (2024) ranges for normal ordering, predicting ${\delta }_{\mathrm{CP}}\simeq \pm (150^{\circ }-180^{\circ })$, $\sum m_{\nu }\simeq (0.06-0.08)\mathrm{eV}$, and an effective Majorana mass $m_{\beta \beta }\simeq (8-18)\times 10^{-3}\mathrm{eV}$, testable in next-generation neutrinoless double-beta decay experiments. The same modular Yukawas yield resonantly enhanced CP asymmetries $|{ϵ}_{L,\chi }|\sim 10^{-9}-10^{-6}$ at $M_{\Sigma }\sim 10^7\mathrm{GeV}$, successfully generating the observed baryon asymmetry ${\eta }_B\simeq 6\times 10^{-10}$ and dark relic density ${\Omega }_{\chi }{h}^2\simeq 0.12$ without additional free parameters. The predicted correlation ${\Omega }_{\chi }/{\Omega }_B\simeq 5.4$ fixes the dark matter mass to $m_{\chi }\simeq 0.1-2\mathrm{GeV}$, consistent with all current constraints. This framework therefore realizes a fully predictive baryon$-$dark matter co-genesis, where the geometry of the modular symmetry links the origin of flavor, CP violation, and the cosmic matter asymmetry.

    hep-phJHEP(2026)·2 citations
18. 18*

    Probing direct $CP$ violation in ${\Lambda }_b^0\to P_c^{+}{h}^{-}$ $(h=\pi ,K)$ with final-state rescattering

    Zhu-Ding Duan🇨🇳 · Tian-Liang Feng🇨🇳 · Run-Hui Li🇨🇳 · Ming-Zhu Liu🇨🇳 · Jian-Peng Wang🇨🇳 · Fu-Sheng Yu🇨🇳

    The LHCb Collaboration recently reported a measurement of the difference in direct CP asymmetries for the decays ${\Lambda }_b^0\to J/\psi p{h}^{-}$ (with $h=K,\pi$), offering new experimental constraints on the decay dynamics of heavy baryons into charmonium final states. Inspired by these findings, we explore the branching ratios and direct CP violations for the decays ${\Lambda }_b^0\to P_c^{+}(4312,4440,4457)h^{-}$ within the framework of final-state rescattering. Our analysis indicates that the branching fractions for ${\Lambda }_b^0\to P_c^{+}{\pi }^{-}$ lie around the $10^{-6}$ level, with the corresponding direct CP asymmetries approaching approximately $1\%$. In contrast, the direct CP violation for the decay ${\Lambda }_b^0\to P_c^{+}{K}^{-}$ is found to be very small, while its branching ratios show a strong dependence on the spin assignments of the $P_c$ states. These predictions may provide useful guidance for more precise CP measurements and amplitude analyses in the $P_c$ region in future experiments.

    hep-phhep-exPRD(2026)·1 citation
19. 19*

    Symmetry-restoring finite counterterms of SMEFT four-fermion operator insertions at one loop

    Sergio Ferrando Solera🇪🇸 · Sebastian Jäger🇬🇧 · Luiz Vale Silva🇪🇸

    Some effects induced by SMEFT operators at one loop have attracted a lot of attention in recent years, in particular, the renormalization of divergences by physical operators in single insertions of dimension-6 operators. Important non-logarithmically enhanced contributions must also be calculated. We discuss dimensional regularization in the Breitenlohner-Maison-'t Hooft-Veltman scheme. The goal here consists of determining in this scheme quantum effects in chiral theories at one loop. Namely, the determination of finite counterterms at one loop that reestablish the Slavnov-Taylor identities, which follow from gauge symmetries. These counterterms are necessary due to the presence of evanescent symmetry-breaking terms in the classical Lagrangian needed to regularize fermion propagators. We consider a technique that allows an easier calculation of such finite effects, relying on the identification of $(D-4)/(D-4)$ terms of one-loop amplitudes with an external ghost leg. We focus on dimension-6 four-fermion operators, identifying all finite counterterms in the Breitenlohner-Maison-'t Hooft-Veltman scheme at one loop, and as expected find no obstructions to the Slavnov-Taylor identities that cannot be cured by finite counterterms. This represents one step towards moving to higher order calculations.

    hep-phhep-thJHEP(2026)·1 citation
20. 20*

    Modern Machine Learning and Particle Physics Phenomenology at the LHC

    Maria Ubiali🇬🇧

    Modern machine learning is driving a paradigm shift in particle physics phenomenology at the Large Hadron Collider. This short review examines the transformative role of machine learning across the entire theoretical prediction pipeline, from parton-level calculations to full simulations. We discuss applications to scattering amplitude computations, phase space integration, Parton Distribution Function determination, and parameter extraction. Some critical frontiers for the field including uncertainty quantification, the role of symmetries, and interpretability are highlighted.

    hep-ph5 citations
21. 21*

    Quantum speed limit time for bipartite entanglement in neutrino oscillations in matter with non-standard interactions

    Abhishek Kumar Jha🇮🇳 · Lekhashri Konwar🇮🇳 · Rukmani Mohanta🇮🇳

    In the three-flavor neutrino oscillation framework, we investigate the transition probabilities of an initial muon neutrino flavor state in the presence of non-standard interactions (NSIs) characterized by complex off-diagonal ($|{ϵ}_{\alpha \beta }|e^{i{\varphi }_{\alpha \beta }}$) and diagonal parameters ($|{ϵ}_{\alpha \alpha }-{ϵ}_{\beta \beta }|$), including a CP-violating phase and a constant matter potential, under both normal (NO) and inverted mass ordering (IO) scenarios. Within these scenarios and through the lens of mode entanglement, bipartite entanglement measures such as entanglement entropy and capacity of entanglement are quantified in terms of the transition probabilities, which can be measured in neutrino oscillation experiments. Using these two bipartite entanglement measures, we further explore the quantum speed limit (QSL) time, which describes how rapidly bipartite entanglement evolves during neutrino oscillations. We illustrate our results using the baseline lengths and energies corresponding to ongoing long-baseline accelerator neutrino experiments, such as T2K, NO$\nu$A, and the upcoming DUNE experiment. In the presence of a CP-violating phase and a constant matter potential, both with and without NSI effects, we compare the QSL time behavior for bipartite entanglement in neutrino oscillations for NO and IO. The most pronounced discrepancies in the QSL time for bipartite entanglement arise from the off-diagonal NSI parameter ${ϵ}_{\mu \tau }$ across both the NO and IO scenarios. We emphasize that among all the experiments considered, NO$\nu$A and DUNE exhibit a rapid suppression of bipartite entanglement in neutrino oscillations in the standard oscillation scenario with NO at the end of their baseline lengths for the corresponding best-fit value of CP-violating phase. Our results hint at a possible imprint of new physics in neutrino oscillations.

    hep-phquant-ph2 citations
22. 22*

    Exploring Higgs EFT in $t\bar{t}hh$ at High Luminosity LHC

    Ricardo D'Elia Matheus🇧🇷 · Oscar J. P. Eboli🇧🇷 · Rafiqul Rahaman🇧🇷 · Aurore Savoy Navarro🇫🇷

    The non-resonant production of a Higgs boson pair in association with a top-antitop quark pair ($pp\to t\bar{t}hh$) has only recently begun to be explored at the Large Hadron Collider (LHC) and provides a unique and largely uncharted probe of the top-Higgs sector, offering complementary sensitivity to the Higgs self-coupling and higher-dimensional interactions beyond the Standard Model. In this work, we present a detailed study of this process within the framework of Higgs Effective Field Theory (HEFT) at the High-Luminosity LHC (HL-LHC). A comparative analysis is performed using a traditional cut-based approach in the single-lepton channel and a multivariate parametric boosted decision tree method in both single-lepton and dilepton final states. We derive one- and two-parameter limits at 95\% confidence level on the HEFT couplings $\delta {\kappa }_{\lambda }$, $c_2$, $c_{2g}$, $c_{tg}$, and $c_{tg2}$. The projected bound on $\delta {\kappa }_{\lambda }$ is weaker than current experimental constraints from dedicated Higgs-pair measurement; however, this coupling plays a critical role in shaping the multidimensional allowed parameter space. For the remaining HEFT couplings, where no direct experimental limits currently exist, our results provide the first sensitivity projections in the $t\bar{t}hh$ channel. Overall, this study demonstrates the strong potential of the $t\bar{t}hh$ production process to probe extended Higgs and top-quark interactions beyond the Standard Model through the exploitation of the $t\bar{t}hh$ data at the HL-LHC.

    hep-phhep-exhep-thJHEP(2026)·3 citations
23. 23*

    QCD Scattering Amplitudes and Prescriptive Unitarity

    Sérgio Carrôlo🇩🇪 · Dmitry Chicherin🇫🇷 · Johannes Henn🇩🇪 · Qinglin Yang🇩🇪 · Yang Zhang🇨🇳

    We present a systematic framework for the maximally-transcendental part of planar QCD scattering amplitudes and perform the first bootstrap computation of six-gluon MHV amplitudes in massless QCD at the symbol level. By analyzing the maximal weight projection of amplitudes at the integrand level, we relate their maximally-transcendental parts to prescriptive unitarity integrals. This reveals a novel analytic structure: the prefactors multiplying the functions of maximal transcendentality are identified with the four-dimensional leading singularities of the theory. As a consequence, these prefactors admit a complete classification and can be computed using on-shell diagrams, a formalism originally developed in $\mathcal{N}=4$ super Yang-Mills theory. As a concrete application, we determine the two-loop prefactors for planar MHV gluon amplitudes at arbitrary multiplicity. Combining these prefactors with recent advances in the planar two-loop six-point function space and explicit six-point prescriptive-unitarity input, we construct a complete symbol ansatz and uniquely fix the maximally-transcendental part of the two-loop six-gluon MHV QCD amplitudes by imposing physical constraints. The resulting symbols are expressible in a reduced 137-letter alphabet, suggesting that this alphabet is complete for two-loop six-point massless MHV scattering. We also discuss the implications for multi-collinear splitting and multi-soft functions.

    ↳ hep-thhep-phJHEP(2026)·13 citations
24. 24*

    Probing beyond the Standard Model with gravitational waves from phase transitions

    Chiara Caprini🇨🇭

    This review article is based on a seminar presented at the Higgs pairs workshop 2025. Stochastic gravitational wave backgrounds can serve as probe of the diverse phenomenology encountered in beyond-Standard-Model scenarios featuring phase transitions in the early Universe. Focussing on gravitational wave production from first-order phase transitions, we present the main results of a recent analysis by the LISA Cosmology Working Group concerning the detectability of such signals with LISA. Strong degeneracies, both among the parameters controlling the phase transition and between these and the parameters of the beyond-Standard-Model scenario underlying the phase transition, complicate the reconstruction of the model from a potential signal. Nonetheless, once a specific scenario is assumed, LISA observations can supply constraints possibly complementary to those obtainable from present and future particle colliders.

    ↳ astro-ph.COhep-phHiHEP(2025)·3 citations
25. 25*

    Evidence for deviation in gravitational light deflection from general relativity at cosmological scales with KiDS-Legacy and CMB lensing

    Guo-Hong Du🇺🇸 · Tian-Nuo Li🇺🇸 · Tonghua Liu🇨🇳 · Jing-Fei Zhang🇺🇸 · Xin Zhang🇺🇸

    General relativity (GR) faces challenges from cosmic acceleration and observational tensions, necessitating stringent tests at cosmological scales. In this work, we probe GR deviations via a $\mu$--$\Sigma$ modified gravity parameterization, integrating KiDS-Legacy weak lensing (WL) data (1347 deg${}^2$, $z\le 2.0$), joint cosmic microwave background (CMB) data from Planck, ACT, and SPT, DESI DR2 baryon acoustic oscillation, and DES-Dovekie supernova data. KiDS-Legacy significantly improves constraint precision: ${\mu }_0$ (matter clustering) by $\sim 60\%$ and ${\Sigma }_0$ (gravitational light deflection) by $\sim 43\%$ relative to CMB alone. In the $\Lambda$CDM background, ${\mu }_0=0.21\pm 0.21$ is consistent with GR, while ${\Sigma }_0=0.149\pm 0.051$ deviates from GR at the 3.0$\sigma$ level. Furthermore, within the observationally preferred $w_0{w}_a$CDM background, this deviation in gravitational light deflection persists at the 2.2$\sigma$ level. This deviation is likely driven by the higher amplitudes in the large-scale CMB lensing measurements. This precise separation of GR-consistent matter clustering and deviant light deflection provides key observational clues for new physics or data systematics. Our work underscores the critical role of synergizing high-precision CMB and WL data in advancing GR tests.

    ↳ astro-ph.COgr-qchep-phhep-thSCPMA(2026)·13 citations
26. 26*

    Jet-associated Balance Functions of Charged and Identified Hadrons in pp Collisions at $\sqrt{s}=13.6$ TeV using PYTHIA8

    Subash Chandra Behera🇮🇹 · Arvind Khuntia🇮🇹

    We present a study of charge balance functions inside jets in proton-proton collisions at $\sqrt{s}=13.6$ TeV using the PYTHIA8 event generator. The balance function is a differential observable of opposite-charge correlations, which is calculated in the jet frame for inclusive charged hadrons and the identified $\pi$, $K$, and $p$. The results show a clear narrowing of the balancing width with increasing jet charged multiplicity, indicating that particle production becomes more localized in momentum space in high-multiplicity jets.This trend resembles features attributed to collective expansion in heavy-ion collisions. The species dependence highlights sensitivity to the redistribution of strangeness and baryon number during string fragmentation and color reconnection. The new CR tune yields a little broader proton balance-function width in $\Delta {\varphi }^{\ast }$ than CP5, hinting at enhanced baryon-production dynamics, whereas meson widths differ only mildly. These comparisons suggest that multiparton interactions and color reconnection contribute to the observed trends, potentially generating collective like features inside jets, especially in high multiplicity jets, via nontrivial color dynamics alongside standard fragmentation. Taken together, the results establish identified hadron balance functions in high multiplicity jets as a sensitive probe of hadronization and provide new constraints for models of small system collectivity.

    ↳ hep-exhep-phnucl-exPRD(2026)·1 citation
27. 27*

    Where Does Tracing of Cosmic Ray in Real Atmosphere Terminate?

    Du-Xin Zheng🇨🇳 · Long Chen🇨🇳 · Ran Huo

    In backtracing simulations, which are widely employed to determine cosmic-ray particle trajectories in the geomagnetic field, the atmosphere is typically approximated as an artificial sharp boundary at some low altitude where the traced trajectory terminates. In this paper, we extend beyond this simplified assumption and investigate two realistic physical processes that terminate cosmic-ray particle propagation in the atmosphere: Bethe-Bloch energy loss mechanisms and hard scattering interactions with atmospheric atoms using total cross sections based on the Glauber-Gribov formalism. The former mechanism dominates at low rigidities (for protons below $\sim 0.57$~GV), while the latter becomes dominant at higher rigidities. Consequently, we introduce two dimensionless variables up to detailed numerical criteria: the relative rigidity shift due to Bethe-Bloch effects ($\Delta \mathfrak{R}/\mathfrak{R}$), and the expected number of hard scattering events ($⟨N⟩$). Using the corrected US Standard Atmosphere 1976 model, we demonstrate that the altitude dependence can be factorized as approximately $\exp (-0.14h/\text{km})$. Additionally, the effect of the local curvature radius of the trajectory near perigee can be similarly factorized. Our calculations indicate that the simplified sharp-boundary altitude should be at least $50$ km with $\Delta \mathfrak{R}/\mathfrak{R}+⟨N⟩\lesssim 1$ for protons, increasing by more than $15$ km for heavy nuclei such as iron.

    ↳ physics.space-phastro-ph.EPhep-phphysics.ao-phCPC(2026)·0 citations
28. 28*

    Electromagnetic Couplings of Dark Domain Walls

    Nemanja Kaloper🇺🇸

    We extend Maxwell electrodynamics with a Chern--Simons coupling to a dark sector top form sourced by domain walls. Cosmic birefringence can arise from a distinct mechanism in which photon polarization is rotated when crossing vacuum interfaces, rather than through adiabatic propagation in a background field. Ultrathin walls induce a finite, frequency-independent polarization rotation generated by an electromagnetic Chern-Simons term localized at the interface. The effect persists even in the absence of ultralight axions or other propagating scalar degrees of freedom. For phenomenologically viable parameters, such walls can generate cosmic microwave background polarization rotation at the level $\Delta \vartheta \sim 10^{-3}$ rad, providing a signature of the topological structure of the dark-sector vacuum.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2026)·7 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.