Wed·Mar 11, 2026Wednesday·March 11, 2026

1. 01*

   Explicit or Implicit? Encoding Physics at the Precision Frontier

   Victor Breso-Pla🇺🇸 · Kevin Greif🇺🇸 · Vinicius Mikuni🇯🇵 · Benjamin Nachman🇺🇸 · Tilman Plehn🇩🇪 · Tanvi Wamorkar🇺🇸 · Daniel Whiteson🇺🇸

   High-performance machine learning tools in particle physics rest on two complementary directions: encoding symmetries explicitly in the architecture, and implicitly learning the structure of the data through large-scale (pre-) training. We compare the performance of the representative L-GATr and OmniLearn models on three especially challenging tasks: reweighting-based unfolding, likelihood-ratio estimation, and weakly supervised anomaly detection. Across all benchmarks, both methods achieve comparable performance given the statistical precision of the finetuning datasets, suggesting that the significant efficiency gains from encoding known particle physics structures are largely method-independent.

   hep-phPRD(2026)·6 citations
2. 02*

   DIS dijet production in Background Field Approach: General formalism and methods

   Tiyasa Kar🇺🇸 · Andrey Tarasov🇺🇸 · Vladimir V. Skokov🇺🇸

   We develop a general formalism for computing physical observables within the background field approach, based on representing propagators of the Feynman diagrams in the background fields as path-ordered exponents. This representation allows systematic expansion of the background fields onto arbitrary linear piecewise contours in coordinate space, yielding gauge-covariant QCD operators to any required order of the expansion. We apply this formalism to DIS dijet production and derive a general form of the cross section in terms of (anti)quark propagators in the background fields, valid in arbitrary kinematics. To demonstrate the versatility of our approach, we consider two kinematic limits. In the back-to-back limit, the expansion contour reduces to that of TMD operators. In this limit we recover the known leading-power results. In the small-$x$ regime, defined by the high-energy power counting for boosted background fields, the expansion contour assumes a staple-like shape. We find that, at the leading eikonal order, the transverse component of the background field $B_i$, though parametrically suppressed relative to the light-cone component, contributes non-trivially through the field-strength tensor $F_{-i}$ and the transverse gauge links. Setting $B_i=0$ recovers the standard CGC result. We also demonstrate matching between the eikonal and back-to-back expansions, providing a quantitative dictionary between these two distinct kinematic regimes.

   hep-phnucl-thPRD(2026)·4 citations
3. 03*

   Axion-neutrino interactions in seesaw models and astrophysical probes

   P.Kivokurtseva🇷🇺

   We study axion-neutrino interactions in neutrino-mass extensions of the Standard Model, focusing on the Type-I and inverse seesaw. In these frameworks the effective coupling $g_{a\nu }$ is tied to the axion scale and can be constrained using existing astrophysical limits on axion couplings to electrons. We then estimate the impact of axion-mediated scattering on neutrino propagation in two benchmarks: resonant interactions with the C$\nu$B and scattering on axion dark matter. In the parameter space allowed by current bounds, the resulting optical depths are extremely small, implying no observable signatures with present sensitivities.

   hep-phastro-ph.HEJETP, Vol. 143, No 2, August 2026·0 citations
4. 04*

   The ultrafine splitting of heavy quarkonium with next-to-next-to-next-to-next-to-leading-order accuracy

   Jose M. Escario🇪🇸 · Andreas Maier🇪🇸 · Clara Peset🇪🇸 · Antonio Pineda🇪🇸

   We compute the hyperfine splitting of P-wave heavy quarkonium states with next-to-next-to-next-to-next-to-leading-order accuracy. The resummation of logarithms with next-to-next-to-next-to-next-to-leading-logarithmic accuracy is also addressed. A phenomenological analysis of these results is performed for bottomonium, charmonium and the $B_c$ system. We also apply these results to positronium, muonium, hydrogen and muonic hydrogen.

   hep-phphysics.atom-phJHEP(2026)·1 citation
5. 05*

   Linking Axions, the Flavor Problem, and Neutrino Masses through a Flavored Peccei-Quinn Symmetry

   Yithsbey Giraldo🇨🇴 · Eduardo Rojas🇨🇴 · Juan C. Salazar🇨🇴

   Recent measurements by several experimental collaborations have reported deviations from Standard Model (SM) predictions in diphoton final states, potentially hinting at the existence of intermediate scalar resonances above the electroweak scale. Such anomalies can be naturally accommodated within SM extensions featuring an enlarged scalar sector. In particular, multi-Higgs doublet frameworks arise in Flavored Axion Models (FAMs), which have been proposed to explain the texture zeros of quark mass matrices. These models provide a unified description of quark masses and the Cabibbo-Kobayashi-Maskawa (CKM) mixing matrix while simultaneously addressing the strong CP problem. In this work we study a concrete FAM realization augmented with Majorana masses for right-handed neutrinos, implementing a type-I seesaw mechanism. In this model the flavor structure is effectively determined by the vacuum expectation values of the scalar doublets and Yukawa couplings of order one. Within this framework, neutrino and axion mass scales are intrinsically connected, as the heavy right-handed neutrinos obtain their masses from the scalar field responsible for the spontaneous breaking of the Peccei-Quinn symmetry. We further explore the phenomenological implications of the model, including constraints from flavor-changing neutral currents derived from semileptonic decays, as well as current experimental limits on the axion-photon coupling obtained from axion search experiments.

   hep-ph1 citation
6. 06*

   Scalar contributions to the S, T, U parameters in a 3-3-1 model

   A. Doff🇧🇷 · C. A. de S. Pires🇧🇷

   Electroweak precision tests, expressed through the oblique parameters $S$, $T$, and $U$, impose stringent constraints on physics beyond the Standard Model. Gauge extensions of the Standard Model based on the $SU(3{)}_L\times U(1{)}_N$ symmetry predict a rich scalar and gauge spectrum that contribute to these parameters. Previous studies have shown that 3-3-1 gauge bosons give negligible contributions to the oblique parameters, while the contributions of the scalar sector to these parameters have received comparatively little attention. In particular, for the version of the $SU(3{)}_L\times U(1{)}_N$ model with right-handed neutrinos, the impact of the scalar sector on $S$, $T$ , and $U$ has not yet been addressed. In this work, we fill this gap and address sistematically the scalar contributions to the $S$, $T$ and $U$ within this version. As main result, we show that the parameter $T$ put stringent constraints on the masses and energy scales associated to the spectrum of scalars of the model.

   hep-phPRD(2026)·1 citation
7. 07*

   Dark matter in classically conformal theories: WIMP and supercooling

   Ke-Pan Xie🇨🇳 · Cheng-Hao Zhan🇨🇳

   Beyond solving the hierarchy problem, classically conformal (CC) theories naturally accommodate dark matter (DM). In this work, we explore the CC $SU(2{)}_X$ gauge theory with a triplet dark scalar, uncovering two distinct DM scenarios: weakly interacting massive particle (WIMP) and supercooled DM. The production mechanisms are strongly influenced by the CC model's unique first-order phase transition evolution history, which differs significantly from those in non-conformal models. We obtain the viable parameter space for each scenario and investigate the current constraints and future sensitivities at experiments, demonstrating that gravitational wave signals from the phase transition provide a common detection channel for both the WIMP and supercooled DM regimes.

   hep-phastro-ph.CO2 citations
8. 08*

   Detailed analysis of possible new-physics effects in the semileptonic decay $B_s\to D_s^{(\ast )}\tau \bar{\nu }$

   Mikhail A. Ivanov🇷🇺 · Jignesh N. Pandya🇮🇳 · Pietro Santorelli🇮🇹 · Nakul R. Soni🇮🇳 · Chien-Thang Tran🇻🇳 · Hai-Cat Tran🇻🇳 · Vo Quoc Phong🇻🇳

   We study the semileptonic decays $B_s\to D_s^{(\ast )}\tau \bar{\nu }$ as a promising probe for new physics (NP) beyond the standard model (SM). The extension of the SM is done through the introduction of four-fermion operators beyond the $V-A$ structure with the corresponding Wilson coefficients characterizing their contribution. The constraints on these coefficients are obtained from recent experimental data. Form factors describing hadron transitions are calculated in our covariant quark model with infrared confinement. Theoretical predictions for the full set of observables in these channels are provided. We analyze possible NP effects to be tested in future experiments.

   hep-phPRD(2026)·0 citations
9. 09*

   On the Robustness of type-II Seesaw Collider Searches

   Christoph Englert🇬🇧 · Manimala Mitra🇮🇳 · Wrishik Naskar🇩🇪 · Subham Saha🇮🇳

   Electroweak triplet Higgs sector extensions are well-motivated scenarios to address lepton flavour observations. These models can also be strongly constrained by combining precise, indirect low-energy measurements with direct searches for exotic, doubly charged Higgs bosons. Together, these searches set competitive constraints on the type-II seesaw mechanism. In this work, we consider extensions of the type-II seesaw, specifically through the lens of a modified collider phenomenology. Surveying motivated extensions, we map out changes in expected correlations, focusing on the modified production and decay phenomenology of exotic Higgs particles. This enables us to assess the robustness of the type-II seesaw collider constraints against extended new-physics contributions that modify standard sensitivity expectations and projections.

   hep-phPRD(2026)·4 citations
10. 10*

    Exotic hadrons associated with $b$-quark

    Xinchen Dai🇨🇳 · Sen Jia🇨🇳 · Alexey Nefediev🇩🇪 · Juan Nieves🇪🇸 · Chengping Shen🇨🇳 · Liming Zhang🇨🇳

    Compared to charmonium-like states, exotic hadrons associated with $b$-quark offer distinct advantages for exploring the nature of multiquark phenomena and the dynamics of the strong interaction. Due to the heavier bottom quark mass, theoretical calculations, particularly those based on effective field theories and potential models, tend to be more reliable and under better control in the bottomonium sector. With its clean $e^{+}{e}^{-}$ collision environment and high luminosity, the Belle and Belle II experiments are ideally suited to explore these exotic hadrons associated with $b$-quark, including $Z_b$, $X_b$, and $Y_b$ states, and charmonium-like states in $B$ decays. Utilizing the large proton--proton collision dataset, the LHCb experiment has conducted extensive investigations of heavy-flavor multiquark states through $B$ and ${\Lambda }_b$ decay channels. The relevant phenomenological interpretations are also reviewed.

    hep-phhep-exPhys.Rept.(2026)·11 citations
11. 11*

    Production of muonic kaon atoms at high-energy colliders

    Xiaofeng Wang🇨🇳 · Zebo Tang🇨🇳 · Zhangbu Xu🇺🇸 · Chi Yang🇨🇳 · Wangmei Zha🇨🇳 · Yifei Zhang🇨🇳

    We develop a framework for the formation of exotic muonic kaon atoms ($K\mu$) in semileptonic $D^0$ decays, using the effective weak Hamiltonian, a helicity-based treatment of the leptonic current, and a nonrelativistic bound-state projection. The resulting branching ratio, $\mathrm{BR}(D^0\to (K\mu ){\nu }_{\mu })=2.29\times 10^{-10}$, is implemented in a ROOT-based code to estimate yields at RHIC, LHC, and STCF. We show quantitatively that $K\mu$ atoms-also produced through coalescence in the quark-gluon plasma (QGP)-provide a sensitive probe of low-momentum primordial muons and early time electromagnetic radiation, offering complementary constraints in an otherwise unexplored phase space for thermal dilepton and photon emission. Newly estimated dissociation cross sections in detector material indicate that secondary-vertex reconstruction should be experimentally feasible, allowing clean experimental identification of the atoms. Projected yields from QGP coalescence in LHC and RHIC heavy-ion collisions, and from $D^0$ decays in LHC high luminosity $p+p$ collisions indicate that the first observation of $K\mu$ atoms is within reach.

    hep-phCPC(2026)·0 citations
12. 12*

    Extracting freeze-out conditions in beam energy scan via functional QCD

    Yi Lu🇨🇳 · Christian S. Fischer🇩🇪 · Fei Gao🇨🇳 · Yu-xin Liu🇨🇳 · Jan M. Pawlowski🇩🇪

    Fluctuations of conserved charges provide a link between high quality theoretical results and precision measurements of heavy ion collisions. We compare results for ratios of the lowest order baryon number susceptibilities from functional QCD approaches to proton number cumulants extracted from experiments. We find that they meet at a specific temperature and chemical potential for each collision energy. This is indicative of the respective freeze-out point. From this self-consistent determination of the freeze-out parameters we extract a prediction for the kurtosis on the freeze-out line. We find quantitative agreement with experimental data where available, despite comparing apples (baryons) with oranges (protons). At a collision energy around 5 GeV, our kurtosis exhibits a peak structure indicative of the critical end point of QCD.

    hep-phhep-exnucl-th9 citations
13. 13*

    Scattering of ${\Lambda }_c{\Lambda }_c$ and ${\Lambda }_c{\bar{\Lambda }}_c$ in chiral effective field theory

    Zhe Liu🇨🇳 · Hao Xu🇨🇳 · Zhan-Wei Liu🇨🇳 · Xiang Liu🇨🇳

    We investigate the $S$-wave scatterings of ${\Lambda }_c{\Lambda }_c$ and ${\Lambda }_c{\bar{\Lambda }}_c$ systems within a unified chiral effective field theory framework up to next-to-leading order. The contact low-energy coupling constants are determined by fitting to the lattice QCD results for the ${\Lambda }_c{\Lambda }_c$ scattering phase shift at an unphysical pion mass. After extrapolating to the physical pion mass, we find a repulsive interaction in the $I(J^P)=0(0^{+})$ ${\Lambda }_c{\Lambda }_c$ channel, consistent with the lattice QCD simulation. On the ${\Lambda }_c{\bar{\Lambda }}_c$ side, using the fitted contact low-energy constants, we predict the phase shifts and potentials for ${\Lambda }_c{\bar{\Lambda }}_c$ scattering in the $I(J^{PC})=0(0^{-+})$ and $0(1^{--})$ channels. Attractive interactions are found in both channels, each allowing for the formation of bound states. In particular, the attraction in the $0(1^{--})$ ${\Lambda }_c{\bar{\Lambda }}_c$ channel is stronger. In addition, our analysis reveals that the spin-spin term caused by the two-pion exchange contributes significantly to the interactions, leading to a distinct mass splitting between the $0(0^{-+})$ and $0(1^{--})$ ${\Lambda }_c{\bar{\Lambda }}_c$ channels.

    hep-phhep-lat1 citation
14. 14*

    Beyond QED: Electroweak and hadronic extensions of McMule

    Sophie Kollatzsch🇨🇭

    McMule is a Monte Carlo framework developed to advance the low-energy precision frontier by providing QED corrections to leptonic scattering and decay processes, currently up to next-to-next-to-leading order. Recent developments have extended its capabilities in two important directions: the systematic inclusion of electroweak effects at low energies within the low-energy effective field theory [arXiv:2507.17652], and the incorporation of pion form factors and the non-perturbative hadronic vacuum polarisation in loop amplitudes through a combination of OpenLoops and effective field theory techniques, referred to as disperon QED [arXiv:2512.10709]. I will provide an overview of McMule and discuss these recent extensions and their applications. In particular, I will illustrate the impact of the model used for non-perturbative $\gamma$-$Z$ mixing effects in the context of the MOLLER experiment and highlight the subtlety involved in consistently aligning OpenLoops with its effective field theory expansion in disperon QED.

    hep-ph2 citations
15. 15*

    Vector-like dark matter within an alternative left-right symmetric model

    Yassine Bouzeraib🇩🇿 · Mohamed Sadek Zidi🇩🇿 · Geneviève Bélanger🇫🇷

    We investigate an extension of the left-right symmetric model featuring an additional non-abelian $SU(2)$ gauge symmetry. The particle content is augmented by one generation of vector-like leptons transforming under the fundamental representation of this new gauge group. We demonstrate that the neutral component of the vector-like lepton multiplet naturally provides a viable and stable dark matter candidate. Stability is ensured by imposing a discrete parity symmetry that forbids mixing between the vector-like leptons and the Standard Model leptons. As a consequence, the dark sector interacts with the visible sector exclusively through the vector portal (via s-channel processes) and the vector-like lepton portal (via t-channel processes). In our analysis, we incorporate collider constraints on the mass of the first-generation extra charged gauge boson $W^{\prime \pm }$, while assuming that additional scalar states are decoupled from the relevant energy scale for simplicity. We identify the regions of parameter space consistent with the observed relic abundance, collider bounds on the charged partner $E^{\pm }$, current direct detection limits from the LZ experiment and indirect detection constraints from Fermi-LAT. We find viable dark matter with a mass at the TeV scale. We show the complementarity of direct and indirect searches in probing the remaining parameter space of the model, in particular comparing the prospects of multi-ton direct detection experiments such as XLZD and of the CTA telescope.

    hep-phPRD(2026)·1 citation
16. 16*

    Joint Bayesian analysis of soft and high-$p_{\perp }$ probes yields tighter constraints on QGP properties

    Marko Djordjevic🇷🇸 · Dusan Zigic🇷🇸 · Igor Salom🇷🇸 · Magdalena Djordjevic🇷🇸

    To extract bulk QGP properties, we perform a joint Bayesian calibration of bulk-medium parameters using low-$\text{pt}$ bulk and high-$\text{pt}$ tomography within a common medium evolution. Low-$\text{pt}$ observables are computed with \textsc{TRENTo}+\textsc{VISHNU}; temperature profiles are passed to \textsc{DREENA-A} to predict light/heavy $R_{\mathrm{AA}}(\text{pt})$ and $v_2(\text{pt})$. Gaussian-process emulation enables Hamiltonian Monte Carlo sampling of the low-$\text{pt}$-only and joint posteriors. The low-$\text{pt}$-only case underpredicts high-$\text{pt}$ anisotropy; the joint calibration matches both sectors and markedly tightens bulk-parameter constraints, demonstrating the added power of high-$\text{pt}$ data.

    hep-phnucl-th0 citations
17. 17*

    Circumstellar Medium of Supernovae as New Probes for Feebly-interacting Particles

    Yu Cheng🇰🇷 · Chui-Fan Kong🇰🇷 · Yen-Hsun Lin🇹🇼 · Meng-Ru Wu🇹🇼 · Seokhoon Yun🇰🇷

    We propose a novel strategy to probe feebly-interacting particles (FIPs) by exploiting the dense, confined circumstellar medium (CSM) surrounding core-collapse supernovae (CCSNe). FIPs produced in the proto-neutron star can deposit substantial visible energy into the CSM via decay prior to the shock breakout from the progenitor star. This energy injection heats and ionizes the CSM, establishing a FIP-induced photosphere that generates distinctive precursor blackbody emission. Using early-time observations of SN 2023ixf, we translate the non-detection of excessive precursor luminosity into stringent new constraints on MeV-scale dark photons as an exemplary model. Our results significantly extend existing CCSN bounds and exclude previously unexplored regions of parameter space. We further demonstrate that the FIP-induced dust sublimation offers robust diagnostics for future Galactic SNe, opening a new avenue to explore the dark sector.

    hep-phastro-ph.HE0 citations
18. 18*

    JLab and J-PARC for the J/{\ensuremath{\psi}} Production at the Threshold

    Igor I. Strakovsky (GWU)🇺🇸 · Jung Keun Ahn (Korea U.)🇰🇷 · William J. Briscoe (GWU)🇺🇸 · Misha G. Ryskin (PNPI)🇷🇺 · Axel Schmidt (GWU)🇺🇸

    New threshold measurements for $\gamma p\to pJ/\psi \to p({\mu }^{+}{\mu }^{-})$ by 007 and ${\gamma }^{\ast }p\to pJ/\psi \to p(e^{+}{e}^{-})$ by CLAS12 allow us to extend the previous phenomenological determination of the J/\ensuremath{\psi}-proton scattering length, ${\alpha }_{J/\psi p}$, using GlueX threshold data for $\gamma p\to pJ/\psi \to p(e^{+}{e}^{-})$. The agreement between all three J/\ensuremath{\psi} data sets shows no indication of systematic differences between methodologies. Furthermore, perturbative QCD predictions support the phenomenological determination of heavy vector meson-nucleon scattering lengths. The role of the nucleon form factor, $F_N$, is discussed, and a possible correction to the phenomenological scattering length for heavy vector meson photoproduction is calculated using the pole form of $F_N$. Upcoming J-PARC threshold measurements of the reaction ${\pi }^{-}p\to nJ/\psi \to n(l^{+}{l}^{-})$ will help to evaluate the possible role of heavy pentaquark, $P_c$, states in low-energy $J/\psi$ production and the effects caused by the nucleon form factors.

    hep-phhep-exnucl-exnucl-thPRD(2026)·2 citations
19. 19*

    The eikonal spin-dependent Odderon and gluon Sivers function of a proton, and its small-$x$ evolution

    Sanjin Benić🇭🇷 · Adrian Dumitru🇺🇸 · Florian Hechenberger🇺🇸 · Tomasz Stebel🇵🇱

    The matrix element in the proton of the eikonal Odderon operator, with a helicity flip, has been shown to correspond to the dipole gluon Sivers function. We employ a three quark light-front model of the proton to determine the Sivers function at moderately small $x_0\sim 0.1$ and transverse momentum $k_{\perp }\lesssim 1$~GeV. The model light-cone (LC) wave function predicts the properties of $x{f}_{1T}^{\perp g}(x,k_{\perp })$ such as its overall magnitude, the position of its peak in $k_{\perp }$, and its behavior at small $k_{\perp }$. We then compute numerically the BFKL anomalous dimension characterizing the power-law tail at $k_{\perp }\gtrsim 1.5$~GeV of the gluon Sivers function at small (but pre-asymptotic) LC momentum fractions, ${\alpha }_s\log x_0/x=1$: $x{f}_{1T}^{\perp g}(x,k_{\perp })\sim k_{\perp }^{-3.3}$.

    hep-phnucl-thPRD(2026)·2 citations
20. 20*

    Directed flow of D and B mesons in an electrically and chirally conductive QGP at LHC energies

    Ankit Kumar Panda🇨🇳 · Pooja🇫🇮 · Maria Lucia Sambataro🇮🇹 · Salvatore Plumari🇮🇹 · Santosh K. Das🇮🇳

    We investigate the directed flow of D and B mesons in the presence of electromagnetic fields incorporating finite electrical and chiral conductivities at LHC energies. The momentum evolution of heavy quarks in the quark-gluon plasma (QGP) is studied using Langevin dynamics, with their interactions with the medium described within the extended quasiparticle model (QPMp) framework. The electromagnetic fields are obtained from analytical solutions of Maxwell equations that account for both electrical and chiral conductivities. These conductivities modify the space-time evolution of the electromagnetic fields and influence the splitting of the directed flow between mesons and anti-mesons. However, the influence of chiral conductivity remains secondary to that of electrical conductivity and its impact on the directed flow is marginal. The results show that heavy mesons containing a charm quark develop a directed flow with a sign opposite to that of heavy mesons containing a bottom quark, with a smaller magnitude for the latter. The present study indicates that a simultaneous experimental measurement of v1 for heavy mesons containing both charm and bottom quarks would provide valuable insight into the electromagnetic field origin of v1 for heavy quarks.

    hep-phPLB(2026)·2 citations
21. 21*

    Dimuon production in neutrino-nucleus collisions at next-to-next-to-leading order in perturbative QCD

    Ilkka Helenius🇫🇮 · Hannu Paukkunen🇫🇮 · Sami Yrjänheikki🇫🇮

    Charm production in charged-current neutrino-nucleus deep-inelastic scattering (DIS), measured through dimuon final states, remains an important constraint of strangeness in global analyses of parton distribution functions (PDFs). This process has traditionally favored a smaller strange-quark PDF at small momentum fractions $x$ than what the LHC heavy-gauge boson data have indicated. Here, we present a self-contained next-to-next-to-leading-order (NNLO) perturbative QCD calculation of dimuon production in neutrino-nucleus DIS based on semi-inclusive DIS (SIDIS). This process has been previously computed at NNLO through fully inclusive charm production. We discuss the shortcomings of this approach and how they are addressed in the SIDIS picture. We study the perturbative convergence and explore new heavy-quark production channels that become available at NNLO. We find that the NNLO corrections significantly reduce the scale uncertainties at large values of $x$ where the cross sections are enhanced by the NNLO corrections. At small $x$, the NNLO corrections tend to be negative instead, which alleviate the tension between the dimuon and LHC data.

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

    Extracting the speed of sound of QCD from transverse momentum fluctuations

    Mubarak Alqahtani🇸🇦 · Tribhuban Parida🇵🇱 · Jean-Yves Ollitrault🇫🇷

    We extract the speed of sound ($c_s$) in the quark-gluon plasma from ATLAS data on the probability distribution of the transverse momentum per particle, $[p_T]$, in ultra-central Pb+Pb collisions. With an ideal detector, $c_s$ can be inferred from the rise of the mean $[p_T]$ with the collision multiplicity. In practice, however, low-$p_T$ particles escape detection, which biases the analysis. We show how to correct for this bias by using data on the variance of $[p_T]$, as well as information from the recently-measured $v_0(p_T)$. We also introduce a systematic method for deblurring the noise from the hadronization process. Assuming that the size of the quark-gluon plasma is independent of the hadron multiplicity in collisions at zero impact parameter, which is the scenario preferred both by high-energy QCD and heavy-ion data, we obtain $c_s/c=0.496\pm 0.008$ at temperature $T=221\pm 13$~MeV, in perfect agreement with first-principles calculations from lattice QCD.

    hep-phhep-exnucl-exnucl-thPLB(2026)·2 citations
23. 23*

    Probing GPDs in exclusive electroproduction of dijets

    Trambak Jyoti Chall🇮🇳 · Marta Łuszczak🇵🇱 · Wolfgang Schäfer🇵🇱 · Antoni Szczurek🇵🇱

    We summarize the formalism for calculating the exclusive dijet production in $ep\to e^{\prime }jjp$ in collinear QCD factorization, using generalized parton distributions as the soft hadronic input modeled in the double distribution approach. We include all leading-order contributions coming from light sea and valence quark exchanges, and gluon exchanges for both light quark-antiquark ($q\bar{q}$) production and also the heavy $c\bar{c}$ final state. We present results for several differential distributions for the cross section evaluated over a broad region of phase space, covering a wide range of inelasticity and photon virtuality. The gluon and sea contributions exhibit similar shapes, whereas the valence contribution, though relatively small, shows a markedly different behavior. The latter becomes particularly noticeable at large $x_{\mathbb{P}}$, a kinematic region not explored at HERA, but potentially accessible in future measurements at the Electron Ion Collider. This requires further feasibility studies. We also present the azimuthal angle modulation between the leptonic and the outgoing dijet planes for the general case, as well as for the ZEUS kinematic region where we see reasonable agreement with the data for diffractive deep inelastic scattering parameter $\beta \gtrsim 0.4$.

    hep-phPRD(2026)·2 citations
24. 24*

    Event-by-Event Multiplicity Cumulants as Probes of Partonic Energy Loss and Phase Structure in Au+Au Collisions within a Modified HIJING Model

    Y.A. Rusak🇧🇾 · L.F. Babichev🇧🇾

    Event-by-event fluctuations of charged hadron multiplicity, net-baryon, and net-electric charge are investigated in central Au+Au collisions at $\sqrt{s_{NN}}=$ 20-200 GeV using a modified HIJING Monte Carlo generator. The model incorporates QCD-based partonic energy loss formalisms in both hot (quark-gluon plasma) and cold media, eliminating free tuning parameters. At energies above 100 GeV/nucleon, multiplicity and net-charge fluctuations serve as sensitive probes for medium properties, showing strong agreement with STAR data when hot-medium finite-size effects are included. By introducing a probabilistic distribution for a first-order phase transition, we demonstrate that multiplicity cumulant ratios (${\sigma }^2/M$ and $S\sigma$) provide distinctive signatures of a binodal transition, whereas net-charge and net-baryon fluctuations remain relatively insensitive. Furthermore, expanding the kinematic acceptance significantly enhances the sensitivity of these multiplicity fluctuations to the phase transition boundary.

    hep-phnucl-th0 citations
25. 25*

    First Estimation of Model Parameters for Neutrino-Induced Nucleon Knockout Using Simulation-Based Inference

    Karla Tame-Narvaez🇺🇸 · Steven Gardiner🇺🇸 · Aleksandra Ćiprijanović🇺🇸 · Giuseppe Cerati🇺🇸

    To enable an accurate determination of oscillation parameters, accelerator-based neutrino experiments require detailed simulations of nuclear interaction physics in the GeV regime. While substantial effort from both theory and experiment is currently being invested to improve the fidelity of these simulations, their present deficiencies typically oblige experimental collaborations to resort to empirical tuning of simulation model parameters. As the precision requirements of the field continue to become more stringent, machine learning techniques may provide a powerful means of handling corresponding growth in the complexity of future neutrino interaction model tuning exercises. To study the suitability of simulation-based inference (SBI) for this physics application, in this paper we revisit a tuned configuration of the GENIE neutrino event generator that was originally developed by the MicroBooNE collaboration. Despite closely reproducing the adopted values of four physics parameters when confronted with the tuned cross-section predictions as input, we find that our trained SBI algorithm prefers modestly different values (within MicroBooNE's assigned uncertainties) and achieves slightly better goodness-of-fit when inference is run on the experimental data set originally used by MicroBooNE. We also find that our trained algorithm can create a fair approximation of an alternative neutrino scattering simulation, NuWro, that shares only a subset of its physics model parameters with GENIE.

    hep-phcs.AIhep-exphysics.comp-ph2 citations
26. 26*

    Heavy dibaryons ${\Xi }_{cc}^{(\ast )}{\Xi }_{cc}^{(\ast )}$ and ${\Xi }_{bb}^{(\ast )}{\Xi }_{bb}^{(\ast )}$

    An-Su Lu🇨🇳 · Mao-Jun Yan🇨🇳 · Chun-Sheng An🇨🇳 · Cheng-Rong Deng🇨🇳

    We systematically investigate the dibaryons ${\Xi }_{cc}^{(\ast )}{\Xi }_{cc}^{(\ast )}$ (di-${\Xi }_{cc}$) and ${\Xi }_{bb}^{(\ast )}{\Xi }_{bb}^{(\ast )}$ (di-${\Xi }_{bb}$), with various isospin-spin configurations $I(J^P)$ in a nonrelativistic quark model. For the di-${\Xi }_{cc}$ system, only the single channels ${\Xi }_{cc}{\Xi }_{cc}^{\ast }$ and ${\Xi }_{cc}^{\ast }{\Xi }_{cc}^{\ast }$ with $0(1^{+})$ are capable of forming deuteronlike bound states, with the $\sigma$ meson exchange playing a decisive role. Those states have binding energies of approximately $-1.5$ MeV and $-3.3$ MeV and sizes of 2.37 fm and 1.87 fm, respectively. The coupled channel effect in the di-${\Xi }_{cc}$ system with $0(1^{+})$ enhances the attraction. As a result, this di-${\Xi }_{cc}$ system can establish a deuteronlike configuration, with the binding energy of $-7.5$ MeV relative to the threshold ${\Xi }_{cc}{\Xi }_{cc}$ and the size of approximately 1.40 fm. For the di-${\Xi }_{bb}$ system, the single channels with $0(1^{+})$, $0(2^{+})$, and $0(3^{+})$ can give rise to deuteronlike bound states with binding energies ranging from $-6.1$ MeV to $-14.3$ MeV. Additionally, the di-${\Xi }_{bb}$ system with $1(0^{+})$ and $1(2^{+})$ can also establish deuteronlike bound states with binding energies of around $-0.5$ MeV. When considering the coupled channel effect in the di-${\Xi }_{bb}$ system with $0(1^{+})$, a compact hexaquark state is formed, exhibiting a binding energy of $-21.2$ MeV relative to the threshold ${\Xi }_{bb}{\Xi }_{bb}$ and a size of 0.53 fm. In this state, the $\pi$ meson exchange provides a very powerful attractive force. The meson exchange interactions in the quark model is dispensable in the di-${\Xi }_{bb}$ bound states, except for ${\Xi }_{bb}^{\ast }{\Xi }_{bb}^{\ast }$ with $1(0^{+})$.

    hep-phPRD(2026)·1 citation
27. 27*

    Subtracted Dispersion Relations for Virtual Compton Scattering off the Proton

    I. Danilkin🇩🇪 · B. Pasquini🇮🇹 · M. Ronchi🇩🇪 · M. Vanderhaeghen🇩🇪

    We present a once-subtracted dispersion relation (DR) formalism for the virtual Compton scattering (VCS) process from threshold up to the $\Delta (1232)$ energy region. The formalism aims at extracting the nucleon's electric and magnetic generalized polarizabilities from the $e^{-}p\to e^{-}\gamma p$ process, in view of the precision goals of the present and near future experiments at Jefferson Lab. The present work improves upon the existing unsubtracted DR formalism in several ways. The required $s$- and $t$-channel discontinuities in the subtracted dispersion integrals are obtained in a largely data-driven manner in this energy region. The $s$-channel dispersive integrals are reconstructed from ${\gamma }^{\ast }p\to \pi N\to \gamma p$ using pion photo- and electro-production data, while the $t$-channel dispersion integrals are evaluated from ${\gamma }^{\ast }\gamma \to \pi \pi \to N\bar{N}$ using recent dispersive analyses of both the ${\gamma }^{\ast }\gamma \to \pi \pi$ and $\pi \pi \to N\bar{N}$ processes. We compare our results to VCS data and show the sensitivity of the observables to the nucleon's scalar generalized polarizabilities, which enter the present formalism as subtraction constants.

    hep-ph0 citations
28. 28*

    Scattering observables and correlation function for $p{f}_1(1285)$ revisited

    Pablo Encarnación🇪🇸 · Albert Feijoo🇪🇸 · Eulogio Oset🇪🇸

    In view of the recent theoretical developments in the fixed center approximation for the scattering of a particle with a a two-body cluster, implementing elastic unitarity on the standard fixed center formalism, and the imminent availability of ALICE data on the correlation function of the $p{f}_1(1285)$ system, we update the results of a previous work for this correlation function and the low-energy scattering observables. The new results show appreciable changes in some observables and should provide valuable input for comparison with the forthcoming experimental data. Such a comparison is expected to yield relevant information on the nature of the axial-vector meson states.

    hep-phPRD(2026)·5 citations
29. 29*

    Polarization transfer in ${\psi }^{\prime }\to \psi \pi \pi$: a complete spin density matrix analysis framework

    Jiabao Gong🇨🇳 · Guanyu Wang🇨🇳 · Dongyu Yuan🇨🇳 · Libo Liao🇨🇳 · Yilun Wang🇨🇳 · Jiarong Li🇺🇿 · Xiaoshen Kang🇨🇳 · Lei Zhang🇨🇳 · Jin Zhang🇨🇳 · Gang Li🇨🇳

    A theoretical framework based on the Spin Density Matrix (SDM) formalism is developed to describe polarization transfer in the decay chain $e^{+}{e}^{-}\to {\psi }^{\prime }\to \psi \pi \pi$. Explicit relations connecting the SDMs of ${\psi }^{\prime }$ and $\psi$ are derived, generalizing Cahn's analysis into a complete SDM treatment. For the dominant $S$-wave $\pi \pi$ emission, the SDM is shown to be perfectly preserved, ${\rho }_{\psi }={\rho }_{{\psi }^{\prime }}$, rendering the $\psi$ an ideal probe of the initial polarization state. Deviations arising from $D$-wave contributions are quantified, and a self-consistency experimental test is proposed that simultaneously validates the framework and constrains partial wave amplitudes. This formalism provides a consistent basis for extracting $\psi$ polarization and for amplitude analyses of subsequent $\psi$ decays in a continuum-background-free environment. The framework extends to other hadronic transitions, including ${\psi }^{\prime }\to h_c{\pi }^0$ in charmonium and ${\rm Y}(nS)\to {\rm Y}(mS)\pi \pi$ in bottomonium, as well as to electroweak processes such as $e^{+}{e}^{-}\to Z^{\ast }\to ZH$, where the same angular-momentum structure governs polarization transfer -- offering a unified probe of dynamics from charmonium to the Higgs sector.

    hep-phhep-ex0 citations
30. 30*

    Jet energy loss in anisotropic plasmas meets limiting attractors

    Kirill Boguslavski🇦🇹 · Lucas Hörl🇦🇹 · Florian Lindenbauer🇦🇹

    We consider the energy loss of a high-energy parton in the early anisotropic plasma in heavy-ion collisions. Working in the harmonic approximation, we compute the change in the mean energy of an emitted gluon in the presence of an anisotropic background, characterized by anisotropic jet quenching parameters ${\hat{q}}_x\ne {\hat{q}}_y$. Evaluating the resulting integrals numerically, we compare with isotropic media, and obtain a simple pocket formula to estimate the impact of anisotropy on the mean emitted gluon energy, which is generally small. We then combine our results with the values of the jet quenching parameter extracted from QCD kinetic theory simulations and show that the medium length dependence of this mean energy loss exhibits the characteristics of limiting attractors, which can be obtained by extrapolating to zero and infinite coupling. Our study thus relates energy loss of jet partons to universal dynamics of anisotropic plasmas.

    hep-phhep-exnucl-th0 citations
31. 31*

    Back-to-back dijet production in DIS with finite-energy corrections and twist-3 gluon TMDs

    Tolga Altinoluk🇵🇱 · Guillaume Beuf🇵🇱 · Alina Czajka🇵🇱 · Cyrille Marquet🇫🇷

    This work presents the summary of calculation of the cross section of the dijet production in deep inelastic scattering at small x at next-to-eikonal accuracy. The cross section is calculated in the back-to-back limit of the produced jets using results obtained in our previous works. The cross section is expressed via the transverse-momentum-dependent (TMD) parton distributions. Specifically, we show how the next-to-eikonal corrections are related to the $x$ dependent phase of twist-2 gluon TMD and to twist-3 unpolarized gluon TMDs.

    hep-phPoS(2026)·0 citations
32. 32*

    Stodolsky effect in the framework of Generalised Neutrino Interactions

    Siddhartha Bandyopadhyay🇮🇳 · Ujjal Kumar Dey🇮🇳

    We study the Stodolsky effect utilizing the most general form of neutrino interactions with electrons below the electroweak scale by considering all possible Lorentz invariant operators respecting SU(3)$\otimes$U(1) symmetry. We perform our calculation for both Dirac and Majorana neutrinos and find that in the most general setting, only the non-standard neutrino interactions and the tensor interaction terms provide a non-zero contribution, apart from the Standard Model contribution. We investigate the implications for the possible detection of the cosmic neutrino background (C$\nu$B) by analysing the energy shifts that are characteristic of the Stodolsky effect. We also discuss the implication of considerable asymmetry in the C$\nu$B on the present scenario.

    hep-phastro-ph.CO0 citations
33. 33*

    Production of global vortices with quantum mediation

    Omer Albayrak🇺🇸 · Tanmay Vachaspati🇺🇸

    We study global vortex production in (numerical) scattering experiments when the scatterer and the vortex degrees of freedom interact only due to intermediary quantum variables. We work in $2+1$ dimensions with a complex scalar field, $\varphi$, that supports global vortices, a real scalar field, $\psi$, that is the scatterer, and a quantum field, $\rho$, that couples to both $\varphi$ and $\psi$, acting as a mediator. We simulate the scattering of relativistic Gaussian wavepackets of $\psi$ and scan parameter space for regions where vortex-antivortex pairs are produced. The results show that vortex production is highly sensitive to the initial Gaussian parameters, and the parameter space is chaotic with ``holes" and isolated regions of vortex production.

    hep-phhep-th0 citations
34. 34*

    Detecting Axion-like particles using Cosmic Variance Cancellation with CMB and Radio surveys

    Harsh Mehta🇮🇳 · Anaya Dixit🇮🇳 · Suvodip Mukherjee🇮🇳 · Joseph Silk🇫🇷

    Axions and axion-like particles (ALPs) arise naturally in many extensions of the Standard Model and are among the well-motivated candidates for dark matter. In the presence of magnetic fields of galaxy clusters, the Cosmic Microwave Background (CMB) photons can convert to ALPs, with the efficiency of the process governed by the cluster electron density and magnetic field profiles, the photon-ALP coupling strength ($g_{a\gamma }$), as well as the frequency ($\nu$) of the photon at the redshift of the cluster. The CMB blackbody spectrum suggests this resonant conversion takes place at radio wavelengths as well, following the spectral behaviour of the ALP distortion signal. This opens up a new window to search for ALPs using cosmic variance cancellation (CVC), with multi-frequency tracers of the same phenomenon in CMB photon-ALP resonant conversion. The constraints on the ALP signal ratios from different combinations of microwave and radio bands of Simons Observatory (SO) and Square Kilometer Array (SKA), can be significantly improved using CVC as compared to the case of using auto-only spectra from the two experiments. With the large number of galaxy clusters that will be observed by SO and SKA, we will be able to obtain much more information using CVC, especially for the case of low-mass ALPs with stronger signals. Using the auto-only spectra from galaxy clusters up to redshift $z=1$ for inference of normalized ratio parameter, we obtain a standard deviation of $5.9\times 10^{-2}$ for ALP mass $m_a=10^{-14}\mathrm{eV}$, which improves to $1.3\times 10^{-2}$ using CVC. Not only is this method a universal probe of the ALP distortion signal using its spectral dependence, but will be able to provide a more robust consistency check, helping to identify and mitigate potential spurious signals that might arise in CMB-only analyses, based on its frequency behavior in different bands.

    ↳ astro-ph.COastro-ph.HEhep-phJCAP(2026)·0 citations
35. 35*

    Matter- and magnetically-driven flavor conversion of neutrinos in magnetorotational collapses

    Marco Manno🇮🇹 · Pablo Martínez-Miravé🇩🇰 · Irene Tamborra🇩🇰

    The magnetorotational collapse of massive stars copiously emits neutrinos of all flavors, with a prominent hierarchy between the non-electron and electron flavor average energies. Relying on a three-dimensional neutrino-magnetohydrodynamic simulation of a $13M_{\odot }$ progenitor, we investigate flavor conversion in matter. We find that, in addition to resonant flavor conversion of neutrinos and antineutrinos in matter, (anti)neutrinos experience chirality-flipping interactions due to their non-zero magnetic moment ($\mu \lesssim 10^{-12}{\mu }_B$) and large magnetic field in the source ($B\simeq 10^{15}$ G). For Majorana neutrinos, this leads to resonant flavor-changing neutrino-antineutrino mixing. The event rate expected from a Galactic collapse at current and next-generation neutrino telescopes, such as IceCube and Hyper-Kamiokande, strongly depends on the orientation of the magnetorotational collapse with respect to the observer direction and flavor conversion scenario. The event rate is expected to be larger for an observer facing head on the jet launched during the stellar collapse and peaks around $400$-$600$ ms after bounce. Our work highlights that understanding the rich phenomenology of flavor conversion in magnetorotational collapses is essential to take full advantage of the joint detection of neutrinos and gravitational waves from these sources.

    ↳ astro-ph.HEhep-phClass.Quant.Grav.(2026)·5 citations
36. 36*

    New Construction of Black Hole Solution in Non-Commutative Geometry and Their Thermodynamic Properties

    Abdellah Touati

    In this work, we present a new construction of black hole solutions in non-commutative gauge theory by applying the Seiberg-Witten map directly to interaction potentials before solving Einstein's equations. This approach provides a dynamical effect of spacetime non-commutativity that preserves gauge covariance. We obtain both NC Schwarzschild and charged Reissner-Nordstrom-like black hole solutions, showing that the charged sector exhibits a novel branch dependence between attractive and repulsive electric interactions absent in the commutative limit. We analyze the geometrical properties, energy conditions, and thermodynamic properties of these spacetimes. Our results reveal that non-commutativity eliminates the temperature divergence at the final evaporation stage, inducing a second-order phase transition, or a Hawking-Page-like phase transition in the presence of pressure. Additionally, linear response analysis indicates high sensitivity to the NC parameter for small black holes. Finally, quantum tunneling investigations for both thermal and non-thermal radiation demonstrate that the NC deformation suppresses the particle-number density and weakens correlations between successive emissions, acting as a barrier to particle escape and supports the formation of a cold finite remnant. From a cosmological standpoint, since these stable remnant possess a fixed Planck-scale mass ($M^{\text{min}}\simeq 2.73M_P$), they provide a dynamically generated, purely gravitational cold dark matter candidate that aligns with dark universe phenomenology while simultaneously resolving the black hole information loss paradox.

    ↳ hep-thhep-phPTEP(2026)·0 citations
37. 37*

    Analytic formulae for non-local magic in bipartite systems of qutrits and ququints

    Giorgio Busoni🇦🇺 · John Gargalionis🇦🇺 · Ewan N. V. Wallace🇦🇺 · Martin J. White🇦🇺

    We conjecture analytic expressions for the non-local magic of bipartite pure qudit states of prime local dimension. Our construction relies on the Schmidt-aligned state attaining the minimum over local unitaries, a hypothesis that we support with numerical evidence for pairs of qutrits and ququints. For composite local dimensions, we find that the analogous expressions do not in general reproduce the global minimum, but can still provide computationally cheap approximations to the non-local magic. We also find that relations between non-local magic and entanglement diagnostics that hold for two qubits generally do not extend to qutrit and higher-dimensional systems.

    ↳ quant-phhep-phhep-th10 citations
38. 38*

    Non-perturbative determination of the QCD Equation of State up to the electroweak scale

    Michele Pepe (INFN, Milan Bicocca)🇮🇹

    The QCD Equation of State with $N_f=3$ massless quark flavours is determined non-perturbatively over a broad range of temperatures, extending from the electroweak scale down to 3 GeV, and smoothly connecting to the low-temperature regime. The comparison with perturbative predictions shows that, even at temperatures approaching the electroweak scale, the Equation of State can be accurately described only by adding terms beyond the known perturbative series, including non-perturbative contributions. The strategy that allows this investigation in the previously unexplored high-temperature regime combines shifted boundary conditions with a determination of the lines of constant physics based on the running of a non-perturbatively defined renormalized coupling. This methodology is general and can be applied to QCD with four or five massive quark flavours.

    ↳ hep-latastro-ph.COhep-phPoS(2026)·1 citation
39. 39*

    Low-energy atmospheric neutrino flux calculation with accelerator-data-driven tuning

    Kazufumi Sato🇯🇵 · Hiroaki Menjo🇯🇵 · Yoshitaka Itow🇯🇵 · Morihiro Honda🇯🇵

    We have incorporated a hadron interaction tuning based on accelerator data into our atmospheric neutrino flux calculation, which has been used to analyze atmospheric neutrino oscillations at Super-Kamiokande. This new approach enables a more direct evaluation of the flux uncertainty than a conventional tuning using atmospheric muons. The neutrino flux calculated with this new tuning is 5\%--10\% smaller but still consistent with our previously published prediction within its uncertainty. The flavor ratio $({\nu }_{\mu }+{\bar{\nu }}_{\mu })/({\nu }_e+{\bar{\nu }}_e)$ and $\bar{\nu }/\nu$ ratios were consistent with the previous prediction. Based on the measurement errors of the accelerator data, we evaluated the flux uncertainty associated with the new tuning to be 7\%--9\% in the $E_{\nu }<$ 1 GeV region, which was difficult to assess with the conventional tuning. The flux uncertainty in the $1<E_{\nu }<10$ GeV region was evaluated to be 5\%--7\%, which is an improvement over the conventional tuning.

    ↳ astro-ph.HEhep-phPTEP(2026)·1 citation
40. 40*

    Pure Natural Inflation Passes the ACT

    Cristóbal Zenteno Gatica🇪🇸 · Alexandros Papageorgiou🇪🇸 · Matteo Fasiello🇪🇸

    Pure natural inflation is a compelling effectively single-field model of inflation stemming from a top-down approach to the acceleration mechanism. In this short letter we show that such model is compatible with the latest CMB constraints obtained from the Atacama Cosmology Telescope combined with baryon acoustic oscillation data from the Dark Energy Spectroscopic Instrument. Under both the instantaneous reheating hypothesis and standard assumptions for reheating, we rule in a non-trivial fraction of the parameter space. We apply our analysis also to a phenomenological extension of the model and chart its viable parameter space.

    ↳ astro-ph.COgr-qchep-phhep-th3 citations
41. 41*

    Renormalisation and matching of massless scalar correlation functions in Soft de Sitter Effective Theory

    Martin Beneke🇩🇪 · Patrick Hager🇨🇭 · Andrea F. Sanfilippo🇪🇸

    For light and massless scalar fields, cosmological correlation functions suffer from infrared divergences and secular logarithms. Soft de Sitter Effective Theory (SdSET) has been proposed by Cohen and Green as the effective description of the non-trivial dynamics of long-wavelength modes $k_{\mathrm{phys}}<H$ in de Sitter space, which is responsible for the infrared and late-time logarithms, and as a systematic extension of the stochastic approach. In this article, we construct SdSET in dimensional regularisation, including an initial-condition functional. We demonstrate by examples that renormalisation and matching works as for flat-space effective field theories. Adopting massless $\kappa {\varphi }^4$ theory as the UV theory, we match the tree-level trispectrum and six-point function, and the one-loop power spectrum to SdSET, verifying explicitly that SdSET is the appropriate effective field theory for the quantum dynamics of superhorizon modes.

    ↳ hep-thastro-ph.COhep-phJHEP(2026)·7 citations
42. 42*

    Study of quark and gluon jet identification in photoproduction at EIC

    Siddharth Narayan Singh🇺🇸 · Ritu Aggarwal🇮🇳 · Manjit Kaur🇮🇳

    This paper presents a systematic study of the substructure of dijets produced in direct and resolved photoproduction events and subsequent quark and gluon jet identification in dijets, considering the kinematic reach of the upcoming Electron-Ion Collider (EIC) experiment. We investigate the substructure of jets produced in dijet photoproduction events with center-of-mass energies $\sqrt{s}=64\text{–}140$ GeV at the EIC.~Events are simulated using event generator PYTHIA and contributions from direct and resolved photoproduction subprocesses are analyzed at different energies.~Jets are reconstructed using longitudinally invariant $k_T$ algorithm within the FastJet framework.~Substructure of quark and gluon initiated jets in the selected dijet photoproduction sample is studied in detail by using jet-shape variables.~Predictions for subjet multiplicities and integrated jet shapes are presented in the gluon-initiated and quark-initiated jets in the dijet photoproduction events at the EIC energies.~These results demonstrate the feasibility of distinguishing quark and gluon jets in the photoproduction events at the EIC and provide a baseline for further QCD studies.

    ↳ hep-exhep-phPRD(2026)·1 citation
43. 43*

    How Heavy Can Moduli Be?

    Mehrdad Mirbabayi🇮🇹 · Giovanni Villadoro🇮🇹

    In Kaluza-Klein (KK) compactification of gravitational theories, moduli fields, which are scalar fields associated to the deformations of the compact manifold, are typically lighter than the KK gravitons. However, a universal limit on their mass does not seem to exist. We provide numerical evidence that a light scalar particle, with mass ratio to the first KK graviton $(m_{\mathrm{sc}}/m_{1KK}{)}^2\le 4/3$, is necessary for the consistency of the $4d$ effective theory of KK gravitons. This can be interpreted as a limit on how rigidly the compact manifold can be stabilized.

    ↳ hep-thhep-ph2 citations
44. 44*

    Dark Matter Recoupling

    Eugenia Dallari🇪🇸 · Francesco Castagna🇮🇹 · Emanuele Castorina🇮🇹 · Maria Archidiacono🇮🇹 · Ennio Salvioni🇪🇸

    In the late Universe, and on cosmological scales, dark matter is conventionally assumed to be collisionless, as a consequence of the strong existing bounds on dark matter interactions at the Cosmic Microwave Background last-scattering surface. Challenging this lore, here we show that dark matter interactions can be naturally weak at early times, but then grow to observationally relevant strengths at very late times, even significantly after reionization. This is realized if dark matter recouples to a dark radiation species in the range of redshifts probed by the current generation of galaxy surveys. We systematically study, for the first time, the phenomenology of this dark matter recoupling scenario. A combination of Cosmic Microwave Background and Baryon Acoustic Oscillation data show that the interaction needs to be weak at present, if the entirety of dark matter couples to dark radiation. From a complementary perspective, we estimate that a 4% fraction of dark matter could still be strongly interacting today. Implications for a microscopic model realizing the recoupling dynamics are discussed.

    ↳ astro-ph.COhep-phJCAP(2026)·2 citations
45. 45*

    Does hot QCD have a conformal manifold in the chiral limit?

    Shi Chen🇺🇸 · Aleksey Cherman🇺🇸 · Robert D. Pisarski🇺🇸

    Recent lattice evidence suggests the chiral phase transition in QCD is second-order for $N_f\ge 2$ massless flavors. We constrain CFT descriptions of a critical line in temperature $T$ and imaginary baryon chemical potential ${\theta }_B=i{\mu }_B/T$. An 't Hooft anomaly at general ${\theta }_B$ constrains the transition even at ${\theta }_B=0$, leaving only three minimal scenarios. The best-motivated scenario for $N_f\ge 3$, and perhaps also $N_f=2$, is beyond Ginzburg-Landau, featuring a conformal manifold of ${\theta }_B$-dependent universality classes with an exactly marginal operator related to baryon density.

    ↳ hep-thhep-lathep-phnucl-thPRL(2026)·1 citation
46. 46*

    The Cosmological Simulation Code OpenGadget3 - Implementation of Self-Interacting Dark Matter

    Moritz S. Fischer🇫🇷 · Marc Wiertel · Cenanda Arido🇩🇪 · Yashraj Patil · Antonio Ragagnin🇮🇹 · Klaus Dolag🇩🇪 · Marcus Brüggen🇫🇷 · Mathias Garny🇩🇪 · Andrew Robertson🇫🇷 · Kai Schmidt-Hoberg🇩🇪

    Dark matter (DM) could be subject to non-gravitational self-interactions which is relevant to resolve potential problems of cold DM on small scales. Their impact on astrophysical objects such as galaxies and galaxy clusters allows for constraining the strength of this scattering and eventually further properties of the cross-section. To model self-interacting dark matter (SIDM), N-body simulations are a crucial tool widely employed by the SIDM community. In this paper, we describe the SIDM implementation in the cosmological hydrodynamical N-body code OpenGadget3 and release it to the public. It is capable of simulating elastic scattering for various differential cross-sections, including strongly anisotropic cross-sections. Beyond single-species models, the code also allows simulating a two-species model with cross-species interactions. In addition to describing the numerical schemes for modelling various flavours of SIDM, we discuss the technical challenges of implementing them. Moreover, we demonstrate through several test problems that OpenGadget3 can accurately simulate DM self-interactions. Furthermore, we assess the performance of the code and provide scaling tests. Lastly, we highlight remaining challenges in the context of SIDM and describe directions for improving the current state of the art.

    ↳ astro-ph.IMastro-ph.COhep-phphysics.comp-ph5 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.