Thu·Feb 26, 2026Thursday·February 26, 2026

1. 01*

   Coherent Quantum Evaluation of Collider Amplitudes for Effective Field Theory Constraints

   Yacine Haddad🇨🇭 · Kaidi Xu🇩🇪 · Vincent Croft🇳🇱 · Jad C. Halimeh🇩🇪 · Michele Grossi🇨🇭

   Precision measurements at electron-positron colliders provide stringent tests of the Standard Model and powerful probes of possible higher-dimensional interactions. We present a hybrid quantum-classical framework for computing leading-order helicity amplitudes for $e^{+}{e}^{-}\to {\ell }^{+}{\ell }^{-}$ scattering on gate-based quantum hardware and using the resulting cross sections to constrain both Standard Model couplings and effective field theory operators. In our approach, external kinematics are encoded into single-qubit Weyl spinors, and full helicity amplitudes are reconstructed by coherently combining diagrammatic contributions within a single quantum circuit. Classical post-processing yields physical amplitudes and differential cross sections that can be directly compared with collider data. As a proof of concept, we compute unpolarised angular distributions and perform binned likelihood fits to precision electron-positron measurements. The extracted bounds are statistically consistent with Standard Model expectations, demonstrating that quantum-assisted amplitude evaluation can interface directly with phenomenological analyses and experimental data. This work establishes a concrete pathway toward applying quantum computing to precision collider physics and effective field theory studies.

   hep-phhep-exquant-ph1 citation
2. 02*

   Precision measurements of 2-3 oscillation parameters in the next-generation long-baseline experiments

   Ritam Kundu🇮🇳

   Over the past few decades, data from leading neutrino experiments have firmly established neutrino oscillation, implying non-zero neutrino masses and leptonic mixing and thereby providing confirmed evidence of physics beyond the Standard Model. On the backdrop of the precision era of neutrino oscillation, this thesis underscores its relevance by demonstrating the physics reach of the forthcoming long-baseline experiments -- Deep Underground Neutrino Experiment (DUNE) and Hyper-Kamiokande (Hyper-K) -- to establish non-maximal ${\theta }_{23}$, resolve the correct ${\theta }_{23}$ octant, and improve the precision on ${\theta }_{23}$ and $\Delta m_{31}^2$ by efficiently breaking parameter degeneracies. This is enabled by DUNE's high-resolution LArTPC detector and its wide-band beam, achieving sensitivity at a high confidence level compared to the global fits of world neutrino data. The combined analysis of DUNE and Hyper-K not only significantly enhances sensitivity to these phenomenological studies but also demonstrates their capabilities at lower exposures when operated together, relative to their nominal individual exposures. In addition, we investigate the impact of flavor-dependent long-range interactions arising from anomaly-free U(1)' extensions of the Standard Model, showing that although subdominant long-range interactions can substantially influence the sensitivity and precision of oscillation parameter measurements, the complementary strengths of DUNE and Hyper-K mitigate these challenges to a large extent.

   hep-phhep-exphysics.ins-det0 citations
3. 03*

   Elastic neutrino-electron scattering perspectives at nuclear reactors

   Luis A. Delgadillo🇨🇳 · Qishan Liu🇨🇳 · Randhir Singh🇨🇳

   The determination of the weak mixing angle, ${\sin }^2{\theta }_W$, at low momentum transfers remains a powerful test of the Standard Model and its potential new physics extensions. In this paper, we explore some physics opportunities at present and future reactor neutrino experiments through elastic neutrino-electron scattering (E$\nu$ES). We assess the expected sensitivity to the weak mixing angle considering the CLOUD, TAO, and DANSS experimental configurations. We find that both CLOUD and TAO may achieve a precision that surpasses the current global fit from reactor experiments, while DANSS alone is expected to surpass the benchmark precision set by TEXONO measurement of the weak mixing angle. Additionally, we derive projected upper limits for the non-standard neutrino interactions (NSI), effective neutrino magnetic moment (${\mu }_{\nu }$) and translate these into constraints on the neutrino transition magnetic moments (${\Lambda }_i$). Our results demonstrate the physics potential of the E$\nu$ES channel at current and upcoming reactor-based neutrino experiments.

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

   Holographic QCD equation of state constrained by lattice QCD: neural-ODE for probe-limit and a back-reaction test

   Yutian Deng🇨🇳 · Mei Huang🇨🇳 · Lin Zhang🇨🇳

   We study the equation of state (EoS) of QCD matter in a bottom-up holographic setup that combines an Einstein-Maxwell-dilaton (EMD) sector with an improved Karch-Katz-Son-Stephanov (KKSS) flavor action. In the probe approximation, we perform an inverse reconstruction of the model functions by parameterizing them with neural networks and solving the EMD equations via a differentiable ODE solver (a neural ODE framework), calibrating the model to a $(2+1)$-flavor lattice-QCD EoS at finite temperature and finite baryon chemical potential. The reconstructed model functions are then parametrized and kept fixed across thermodynamic states. Next, viewing the EMD sector as an effective description of pure Yang--Mills theory, we fix its parameters by fitting the ${\mu }_B=0$ lattice pure-glue EoS using a hybrid optimization strategy. Finally, we go beyond the probe limit and solve the coupled EMD$+$KKSS equations with back-reaction, using the pure-glue-calibrated EMD sector as a fixed input and varying the KKSS couplings to compare with the ${\mu }_B=0$ two-flavor lattice EoS. We find a visible mismatch and a high-temperature behavior in which the back-reacted dimensionless ratios approach a nearly ${\beta }_1$-insensitive plateau close to the pure-glue baseline, providing a simple structural diagnostic for the present flavor-sector truncation.

   hep-phCPC(2026)·4 citations
5. 05*

   Study of the decay pattern of $f_0(1370)$ as a $\kappa \bar{\kappa }$ molecular state

   Yin Cheng🇨🇳 · Bing-Song Zou🇨🇳

   Under the hypothesis that the $f_0(1370)$ is a $\kappa \bar{\kappa }$ molecular state, we calculate the partial widths of its various decay channels, including the two-body decay $K\bar{K}$, $\pi \pi$, $\eta \eta$ and the four-body decay $\rho \rho /\sigma \sigma \to 4\pi$ and $K\bar{K}\pi \pi$. The coupling of $g_{f_0(1370)\kappa \bar{\kappa }}\approx 13$ GeV estimated from the Weinberg criterion yields a width of $f_0(1370)$ significantly smaller than the experimental data. By adjusting this coupling to $25\sim 40$ GeV, the total width of $f_0(1370)$ can be fitted to the measured value $200\sim 500$ MeV. At the center-of-mass energy $\sqrt{s}=1.37$ GeV, the channels that mainly contribute to the total width are $K\bar{K}$, $\pi \pi$ and $4\pi$ ranked as $\Gamma (K\bar{K})>\Gamma (4\pi )\approx \Gamma (\pi \pi )$ with $g_{f_0(1370)\kappa \bar{\kappa }}=35$ GeV. Around $1.37$ GeV, the decay widths of the two-body channels $K\bar{K}$, $\pi \pi$ and $\eta \eta$ remain stable with variation in $\sqrt{s}$, whereas the decay widths of the four-body channels $4\pi$ and $K\bar{K}\pi \pi$ increase continuously with $\sqrt{s}$. Most current data are model-dependent and conflicting, particularly regarding the conclusion of $4\pi$ dominance and the ratio of $K\bar{K}$ to $\pi \pi$ decay widths. The current data can not rule out the $\kappa \bar{\kappa }$ assignment for $f_0(1370)$. Further reliable theoretical and experimental analyses of $f_0(1370)$ are required to reveal its nature.

   hep-phPRD(2026)·0 citations
6. 06*

   Study of the ${\Omega }_{ccc}{\Omega }_{ccc}$ and ${\Omega }_{bbb}{\Omega }_{bbb}$ dibaryons in QCD Sum Rules

   Xu-Liang Chen🇨🇳 · Jin-Peng Zhang🇨🇳 · Zi-Xi Ou-Yang🇨🇳 · Wei Chen🇨🇳 · Jia-Jun Wu🇨🇳

   The recent observation of a family of fully-charm tetraquark states by the LHCb, ATLAS and CMS Collaborations suggests the possible existence of fully-heavy dibaryons. In this work, we investigate the ${\Omega }_{ccc}{\Omega }_{ccc}$ and ${\Omega }_{bbb}{\Omega }_{bbb}$ dibaryons in both the ${}^1{S}_0$ and ${}^5{S}_2$ channels using the method of QCD sum rules. We employ the iterative dispersion relation (IDR) method to efficiently compute the massive five-loop banana diagrams that appear in these systems, and properly address the tricky small-circle divergence problem in the nonperturbative terms. Our analyses reveal that for both charm and bottom systems, the scalar dibaryon lies lower than its tensor counterpart. In $\overline{\text{MS}}$ scheme, the mass of the scalar ${\Omega }_{ccc}{\Omega }_{ccc}$ dibaryon is found to be slightly above the $2{\Omega }_{ccc}$ mass threshold, while the ${\Omega }_{bbb}{\Omega }_{bbb}$ systems may form bound states. However, they are predicted to be much heavier in the on-shell scheme.

   hep-phhep-exhep-latPRD(2026)·2 citations
7. 07*

   Solving stiff dark matter equations via Jacobian Normalization with Physics-Informed Neural Networks

   M. P. Bento🇵🇹 · H. B. Câmara🇵🇹 · J. R. Rocha🇵🇹 · J. F. Seabra🇵🇹

   Stiff differential equations pose a major challenge for Physics-Informed Neural Networks (PINNs), often causing poor convergence. We propose a simple, hyperparameter-free method to address stiffness by normalizing loss residuals with the Jacobian. We provide theoretical indications that Jacobian-based normalization can improve gradient descent and validate it on benchmark stiff ordinary differential equations. We then apply it to a realistic system: the stiff Boltzmann equations (BEs) governing weakly interacting massive particle (WIMP) dark matter (DM). Our approach achieves higher accuracy than attention mechanisms previously proposed for handling stiffness, recovering the full solution where prior methods fail. This is further demonstrated in an inverse problem with a single experimental data point - the observed DM relic density - where our inverse PINNs correctly infer the cross section that solves the BEs in both Standard and alternative cosmologies.

   hep-phcs.LG0 citations
8. 08*

   Resonance-aware parton-shower matching for off-shell top-antitop production with semi-leptonic decays at electron-positron colliders

   Ansgar Denner🇩🇪 · Daniele Lombardi🇮🇹 · Mathieu Pellen🇩🇪 · Giovanni Pelliccioli🇮🇹

   We present full off-shell NLO corrections in QCD obtained with the MoCaNLO code matched to parton shower. A resonance-aware matching procedure has been devised for the MC@NLO method tuned to the Catani-Seymour dipole subtraction. Specifically, we consider the off-shell production of a top-antitop pair in the semi-leptonic decay channel in electron-positron collisions and match it to the final-state QCD parton shower of PYTHIA8. Distortions of resonances' line shapes are avoided by providing the details of the resonance-cascade chain on an event-by-event basis to the parton shower and by adapting the matching accordingly through the introduction of dedicated counterterms.

   hep-phJHEP(2026)·2 citations
9. 09*

   Seedless Reduction of Feynman Integrals

   Leonardo de la Cruz🇫🇷 · David A. Kosower🇫🇷

   We show how to construct a complete set of lowering operators, whose successive application reduces an arbitrary Fenyman integral to a combination of master integrals. The construction builds systems of equations for generic integral indices using IBP-generating vectors. The solution to each system is a lowering operator.

   hep-phhep-th9 citations
10. 10*

    ALP Dark Matter, Cosmological Magnetic Fields and the Direct Collapse Black Hole Formation Scenario

    Ashu Kushwaha (Institute of Science, Tokyo)🇯🇵 · Robert Brandenberger (McGill)🇨🇦

    Assuming that dark matter is an ultralight pseudoscalar particle which couples to electromagnetism like an axion (an ALP), we demonstrate that the coupling of the cosmological magnetic field produced by the ALP field oscillations to the primordial dark matter fluctuations yields a spectrum of gauge field fluctuations which can produce a sufficient flux of Lyman-Werner photons to enable the Direct Collapse Black Hole formation scenario. The induced flux is consistent with the bounds on the excess flux of radio photons from ARCADE2 and EDGES measurements.

    hep-phastro-ph.COastro-ph.GAgr-qc+14 citations
11. 11*

    NASDUCK': Laboratory Limits on Ultralight Dark-Photon Dark Matter with Null-Axis Magnetometry

    Joel Barir🇮🇱 · Itay M. Bloch🇨🇭 · Yair Goldszeft🇮🇱 · Gal Goldstein🇮🇱 · Constantine Feinberg🇮🇱 · Or Katz🇺🇸 · Tomer Volansky🇮🇱

    The dark photon is a well-motivated ultralight dark-matter candidate that may couple to the Standard Model through kinetic mixing. We search for dark-photon dark matter in the mass range $m_{A^{\prime }}{c}^2=4\times 10^{-12}$-$2\times 10^{-9}\mathrm{eV}$ (1-500 kHz) using a three-axis magnetometer inside a large conductive shielded room. We set new laboratory limits on the kinetic-mixing parameter $ϵ$, improving upon previous laboratory bounds by up to three orders of magnitude. Our search exploits a geometry-defined null response along one axis as a noise reference; a subtraction procedure reduces the noise floor and improves sensitivity. These results establish the strongest laboratory constraints in this mass range and illustrate how null-axis magnetometry can broaden terrestrial searches for ultralight vector dark matter.

    hep-phhep-ex0 citations
12. 12*

    Non-anomalous axions: lessons from the Majoron

    Antonio Herrero-Brocal🇪🇸

    We show that when an anomalous and a non-anomalous global symmetries are spontaneously and simultaneously broken, the resulting Nambu--Goldstone boson is associated with the non-anomalous one. Applied to the Majoron, this implies that its underlying symmetry is $B-L$ rather than $L$, naturally resolving the domain wall problem. This result further demonstrates that effective couplings of the form $aF\tilde{F}$ do not uniquely indicate an anomalous origin, allowing the detection of non-anomalous Nambu--Goldstone bosons, such as the Majoron, in searches for axion--gauge boson interactions, potentially serving as evidence for the existence of new charged fermions.

    hep-ph2 citations
13. 13*

    One Sum To Rule Them All: A Second Order Master Rate Sum Rule for Charm Decays

    Margarita Gavrilova🇺🇸 · Yuval Grossman🇺🇸 · Guglielmo Papiri🇺🇸 · Stefan Schacht🇬🇧

    We show that within the Standard Model any system of hadronic weak charm decays related by $U$-spin satisfies the following rate sum rule: (sum of CF and DCS CKM-free rates) divided by (sum of SCS CKM-free rates) = 1, which holds up to second order in $U$-spin breaking. We test this sum rule against available data and find that it is well satisfied in all cases. For systems in which some decay rates have not yet been measured, we use this sum rule to predict the missing rates.

    hep-phhep-exJHEP(2026)·3 citations
14. 14*

    Robust Calibration of Non-Perturbative Models with History Matching

    Andrew Iskauskas🇬🇧 · Max Knobbe🇺🇸 · Frank Krauss🇬🇧 · Steffen Schumann🇩🇪

    We apply, for the first time, Bayes Linear Emulation and History Matching to the calibration of non-perturbative models in Monte Carlo event generators. In contrast to the usual approach of "Monte Carlo tuning", History Matching does not result in best-fit plus ellipsoidal parameter uncertainty estimates but instead identifies all parameter space regions that are consistent with data. This approach leads to a systematic and robust quantification of parametric uncertainties in the models, especially in those challenging cases where different, possibly disjoint, regions of parameter space deliver similar results, which are usually not properly treated with current methodology. We highlight the power of this method with the hadronisation models available through Sherpa: the built-in cluster fragmentation Ahadic and string fragmentation through an interface to Pythia.

    hep-phhep-exJHEP(2026)·3 citations
15. 15*

    Bjorken Flow of Holographic R-Charged Plasmas

    Gustavo de Oliveira🇧🇷 · Willians Barreto🇧🇷 · Romulo Rougemont🇧🇷

    We numerically investigate the time evolution of several physical observables for the so-called 2 R-Charge Black Hole (2RCBH) model undergoing Bjorken flow. The 2RCBH model corresponds to a top-down holographic construction describing a strongly interacting conformal fluid defined at finite temperature and R-charge density. Taken together with previous findings for the purely thermal $\mathcal{N}=4$ Supersymmetric Yang-Mills (SYM) plasma, and the 1 R-Charge Black Hole (1RCBH) model, our results for the 2RCBH model provide strong numerical evidence for the existence of far-from-equilibrium correlations between the non-equilibrium holographic entropy defined through the area of the apparent horizon of dynamical bulk black holes, and the expectation value of the energy-momentum tensor of the dual boundary quantum field theory. Such correlations are relevant in the pre-hydrodynamic stages of some initial data evolved in time, and seem to hold at least for strongly interacting conformal fluids, be they charged or neutral.

    ↳ hep-thhep-phEPJC(2026)·0 citations
16. 16*

    Forward hadron production in proton-air collisions above LHC energies through the fluctuations of extensive air showers

    Lorenzo Cazon🇪🇸 · Ruben Conceição🇵🇹 · Miguel Alexandre Martins🇪🇸 · Felix Riehn🇩🇪

    Primary proton-air interactions at ultra-high energies leave a physically interpretable imprint on the correlated fluctuations of the depth of shower maximum and the muon content in extensive air showers. This imprint reflects the stochasticity in the partition of the primary energy among secondary particles in the first interaction. We show that these fluctuations can be accessed through a probabilistic description that isolates sensitivity to hadronic physics in the initial collision, while treating the subsequent shower development as effectively universal. The uncertainties resulting from this universality are smaller than the spread among current hadronic interaction models and comparable to current experimental uncertainties. Consequently, the joint observable space defined by these two quantities provides a new probe of hadron production in kinematic regimes far beyond the reach of human-made accelerators.

    ↳ astro-ph.HEhep-exhep-ph0 citations
17. 17*

    Choice of Quantum Vacuum for Inflation Observables

    Melo Wood-Saanaoui🇬🇧 · Rudnei O. Ramos🇧🇷 · Arjun Berera🇬🇧

    We investigate the modifications to inflationary observables that arise when adopting an $\alpha$-vacuum instead of the standard Bunch--Davies vacuum for quantum fluctuations during inflation. Within the Starobinsky inflationary model, we compute and compare the scalar spectral index, its running, and the running of the running arising from different choices of the initial vacuum state. We further examine the energy scales associated with $\alpha$-vacua and argue that, for any number of extra spatial dimensions, the relevant scale can be truncated at the Hubble scale, $\sim$$\mathcal{O}(10^{13})\mathrm{GeV}$, without conflict with current Cavendish-type experimental bounds on sub-millimeter gravity ($\sim$$250\mu \mathrm{m}$). Our analysis demonstrates that the $\alpha$-vacuum is subject to stringent constraints as a viable de~Sitter-invariant alternative to the Euclidean (Bunch--Davies) vacuum, with the corrections that it induces in the inflationary observables being strongly limited by the latest Planck data.

    ↳ gr-qcastro-ph.COhep-phhep-thSymmetry(2026)·3 citations
18. 18*

    Searches for new physics beyond the Standard Model in hyperon sector

    Jianyu Zhang🇨🇳 · Jinlin Fu🇨🇳 · Hai-Bo Li🇨🇳

    Hyperon physics offers a distinctive laboratory for probing the intensity frontier and searching for physics beyond the Standard Model. This review summarizes recent results from the BESIII experiment, including pioneering studies of dark baryons, massless BSM particles, and invisible decay modes, together with investigations of baryon- and lepton-number violation. A central highlight is the determination of the $\Lambda$ electric dipole moment using quantum-entangled hyperon-antihyperon pairs, achieving a sensitivity three orders of magnitude beyond previous limits. These measurements provide world-leading constraints on new physics scenarios and establish a robust foundation for next-generation precision studies. By integrating experimental progress with theoretical developments and future facility prospects, this review emphasizes the critical role of hyperon probes in testing the fundamental laws of nature.

    ↳ hep-exhep-phChin.Phys.Lett.(2026)·2 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.