HEP Phenomenology·hep-ph

Fri·Oct 2, 2026Friday·October 2, 2026

52 papers—38 primary·14 cross-listed

01
Expanding quantum Proca field
Bogdan Damski
We consider the Proca theory of a real massive vector field coupled to an external current. This theory allows for non-conservation of the charge associated with the external current. It is so because the total conserved current is given by the sum of the external current and the internal current associated with the Proca field, neither of which is required to be conserved separately. Moreover, this theory admits the quantum description of a longitudinal field generated by a charge distribution. We explore both features by studying the quantum dynamics underlying the causal formation of the Proca field following the charge-creation process. The resulting non-equilibrium quantum state exhibits an expanding Proca field accompanied by a moving front. We compare this state with the one representing the corresponding static Proca field and identify fundamental differences between these states. The quantization of the Proca theory in the presence of an external current is discussed in detail. General results concerning the quantum dynamics of this theory are presented. Particular emphasis is placed on the problem of the instantaneous switching-on of an otherwise static external current. An intriguing shockwave structure is found in the point-charge creation problem, the extended-charge creation problem is also discussed.
hep-ph
02
M1 Radiative Transitions in the $B_{c}$ System after the $B_{c}^{*} (1 S)$ Observation: Radial-Node Cancellation and Quark-Line Filtering
Bing-Dong Wan
The recent ATLAS observation of the $B_{c}^{*} (1 S)$ meson fixes the ground-state hyperfine splitting and thereby determines the phase space for $B_{c}^{*} (1 S) \to B_{c} (1 S) γ$ . We study four $1 S$ and $2 S$ M1 radiative transitions using relativistic Salpeter wave functions calibrated to the measured ground-state masses, obtaining $Γ [B_{c}^{*} (1 S) \to B_{c} (1 S) γ] = 5.24 \times 1 0^{- 2}$ ~keV. The allowed transitions show no radial cancellation, whereas the hindered $2 S \to 1 S$ amplitudes are residuals of an approximately twenty-fold cancellation across the radial node. A quark-line-resolved analysis shows a strong asymmetry in the crossed hindered channel: the $b$ -emission contribution undergoes an $O (1 0^{2})$ internal cancellation while the $c ˉ$ contribution remains at $O (20)$ . The corresponding unsigned line strengths show that the small $b$ -current is generated by enhanced cancellation rather than by a smaller unsigned contribution. The unmeasured $B_{c}^{*} (2 S)$ mass remains the main limitation on the $2 S \to 2 S$ radiative width.
hep-ph
03
Dark-State Interference in an Effective Confined Three-Level Color System
S. D. Campos
In this work, a QCD-inspired effective model describes dark-state interference in a confined three-state system with two low-energy $Q Q$ states, $∣1 ⟩$ and $∣2 ⟩$ , and a gluon-excited hybrid state, $∣ H ⟩$ . A stationary chromoelectric flux-tube background enters the unperturbed Hamiltonian, while a time-dependent chromoelectric perturbation couples $∣1 ⟩$ and $∣2 ⟩$ to $∣ H ⟩$ in a $Λ$ -type configuration. Under two-photon\footnote{We retain standard terms like ``two-photon'' from the EIT literature only by mathematical analogy, but they do not refer to electromagnetic photons but to the effective frequencies and energy mismatches of chromoelectric perturbations and gluonic excitations that connect confined states.} resonance and within a Markovian Gorini-Kossakowski-Sudarshan-Lindblad master equation, the system forms a coherent superposition that decouples from $∣ H ⟩$ , strongly suppressing the steady-state probe susceptibility $Im χ_{CE}$ as lower-state decoherence vanishes. A phenomenological non-Abelian correction to the hybrid energy mainly shifts and reshapes the transparency window rather than creating the interference itself. The model is not a first-principles QCD calculation of medium opacity but a controlled effective link between dark-state interference in quantum optics and reduced confined color dynamics.
hep-phhep-thquant-ph
04
Thermal Higgsino Dark Matter in GmSUGRA for the LZ Event and Solar-Neutrino Constraint
Imtiaz Khan · Waqas Ahmed · Tianjun Li · Shabbar Raza · Ali Muhammad
We study the thermal Higgsino dark matter in the Minimal Supersymmetric Standard Model (MSSM) with Generalized Minimal Supergravity (GmSUGRA) boundary conditions after the high-recoil event reported by the LUX--ZEPLIN experiment and the subsequent solar-neutrino limits inferred from IceCube data. The Higgs sector is implemented in a NUHM2-type parametrization with $μ$ and $m_{A}$ as inputs, while the supersymmetry breaking soft terms obey the non-universal GmSUGRA relations. The numerical scan contains a Planck-compatible Higgsino branch near the thermal mass, with the neutral-state splitting extending continuously from the few-hundred-keV region to the MeV scale. The part of this branch with $\dmchi ≃ 0.3$ -- $0.4$ MeV overlaps the kinematic interval relevant to the LZ event, but is disfavored by the current solar-capture reinterpretations for a full-density thermal Higgsino. The same high-scale branch persists at larger splittings, including representative spectra with $\dmchi ≃ 0.85$ , $1.10$ , and $1.34$ MeV, beyond the quoted solar-capture limits. Our results demonstrate that the mass and sub-MeV splitting favored by the LZ high-recoil interpretation can be realized dynamically within a GUT-motivated supersymmetric construction, without imposing the neutralino compression as a weak-scale input. The combined data therefore select different parts of a common GmSUGRA Higgsino branch rather than excluding the thermal Higgsino construction itself.
hep-ph
05
Three-Body Holonomy and $S U (3) \to S U (2) \times U (1)$ Symmetry Breaking
Tadashi Yoshikawa
We show that a three-body holonomy can select the conventional $S U (3) \to S U (2) \times U (1)$ breaking direction. Three particles are special in the present construction: after removal of the center-of-mass coordinate they are the minimal one-dimensional few-body system with a two-dimensional relative space, allowing a closed cycle around the triple-coincidence point once pairwise contacts are encoded by matching conditions. A cyclic three-state mass operator gives \[ M^{[k]}=M_0+2\Delta\cos\!\left(\frac{\theta_3+2\pi k}{3}\right),\qquad k=0,1,2. \] At $θ_{3} = 0$ the spectrum splits as $3 \to 2 + 1$ , and the induced mass operator is proportional to the Cartan generator $T_{8}$ . Its commutant is therefore $S U (2) \times U (1)$ . In a trinification-like embedding, distinct left- and right-sector holonomies leave the hypercharge combination which reproduces the Standard-Model hypercharges for the usual trinification matter assignment. The construction is a toy mechanism for selecting the breaking direction; additional dynamics are required for rank reduction and vacuum selection.
hep-ph
06
Full-event anomaly detection for new physics searches at the Electron-Ion Collider
Dimitrios Athanasakos · Sebastian Grieninger · Hongkai Liu · Tymothy Mangan · Felix Ringer · Robert Szafron
The future Electron-Ion Collider (EIC) will offer new opportunities to search for physics beyond the Standard Model. We study resonant anomaly detection using machine learning and the full particle content of an event. We consider a new neutral gauge boson and a heavy neutral lepton as illustrative signals with different electron-jet topologies. Weakly supervised learning uses this event information to enhance the sensitivity of an invariant-mass search without identifying individual signal events during training. Comparisons with high-level observables show that the electron kinematics account for an important part of the separation, while correlations among the particles provide further sensitivity. We also construct a conditional full-event generator by adapting a model pretrained on LHC jets to produce EIC background events. A scan over signal fractions demonstrates substantial signal enhancement using the learned background reference, providing a proof of concept for this approach at the EIC. Finally, we consider a fully unsupervised graph autoencoder that provides modest signal enhancement but retains sensitivity at signal fractions too small for effective weak supervision. Our results motivate full-event anomaly detection as part of the EIC physics program and identify directions for developing methods suited to its distinct kinematics.
hep-phhep-exnucl-exnucl-th+1
07
Primordial Black Hole and Gravitational Wave by Peaked Cosmic Perturbations from Axion Curvaton
Keisuke Harigaya · Lian-Tao Wang · Jiangyi Yi
We demonstrate that an axion field can develop perturbations peaked at an intermediate wavenumber through its inflationary dynamics. We compute the resultant spectrum of gravitational waves (GWs) and primordial black holes (PBHs) generated through the curvaton mechanism. The GW spectrum exhibits a triangular shape, with UV and IR slopes determined by the axion's inflationary evolution and treatable as free parameters. In computing the PBH abundance, we properly account for the nonlinear relation between curvature and density perturbations and the primordial non-Gaussianity generated by the curvaton. The PBHs can account for all of dark matter, accompanied by blue-tilted isocurvature perturbations at small scales. The IR slope of the GW spectrum is anti-correlated with the magnitude of the dark matter isocurvature perturbations, offering a multi-messenger test of the model.
hep-phastro-ph.CO
08
QCD axion misalignment during reheating
Disha Bandyopadhyay · Debasish Borah · Nayan Das
We study the production of QCD axion dark matter (DM) via vacuum and kinetic misalignment mechanisms during an extended reheating period after the end of slow-roll inflation. With pre-inflationary Peccei-Quinn breaking and considering a monomial inflaton potential during reheating, we classify our study into three different perturbative reheating scenarios in which the inflaton decays into (i) a pair of Standard Model (SM)-like bosons, (ii) a pair of SM-like fermions, or (iii) exclusively into a pair of heavy right-handed neutrinos, which eventually decays into the SM final states after dominating the energy density of the Universe for an intermediate epoch. For each of these reheating scenarios, we study the details of QCD axion relic separately via vacuum and kinetic misalignment mechanisms. For different combinations of reheating, monomial inflaton potential and misalignment mechanisms, we identify the parameter space consistent with the observed DM relic density while satisfying other cosmological and laboratory constraints. We also check the scope of probing the currently allowed parameter space at axion-detection and gravitational wave (GW) experiments.
hep-phastro-ph.CO
09
ALP-Mediated Dark Matter at Low Reheating Temperature and the Belle II Excess
Joel Jones-Pérez · Luca Merlo · Javier Silva-Malpartida
Belle II has reported a $2.7 σ$ excess in $B^{+} \to K^{+} ν ν ˉ$ over its Standard Model prediction, recently interpreted as arising from an axion-like particle mediating a thermal dark matter candidate. We reassess this interpretation using a new mass-differential measurement of the same data set and adding two visible-decay searches that earlier analyses omitted. The resulting bounds leave the predictions from a standard cosmological history only marginally compatible with the excess, viable in a narrow window of parameter space. Thus, we consider a situation where dark matter freezes out during a low-temperature reheating era, featuring entropy injection diluting the relic abundance. This requires smaller couplings compared to those in standard cosmology in order to match the observed dark matter density, opening a region of parameter space where the compatibility of the model with the Belle II excess is significantly improved.
hep-ph
10
The Great Wall of the Standard Model
Yang Bai · Yiming Yang
The global form of the Standard Model (SM) gauge group, $[S U (3)_{c} \times S U (2)_{L} \times U (1)_{Y}] /Γ$ , with $Γ \subseteq Z_{6}$ , remains undetermined. For $Γ = Z_{p}$ , the SM possesses a residual global electric one-form symmetry $Z_{6/ p}$ . Compactification on the thermal circle yields an ordinary discrete zero-form symmetry whose spontaneous breaking can produce cosmological domain walls. We calculate the temperature-dependent tension and width of the $Z_{6/ p}$ domain walls below the electroweak scale, which exist for every quotient except $Γ = Z_{6}$ , finding that their thickness can reach the kilometer scale around reionization in our benchmarks. These macroscopic thermal interfaces, if produced, would constitute the "Great Walls" of the Standard Model. We develop a phenomenological thermal velocity-dependent one-scale model to follow their network evolution, incorporating temperature-dependent surface tension, inertia, and plasma drag. For sufficiently early formation, our benchmarks give an estimated wall energy fraction of order $1 0^{- 14}$ near the onset of Big Bang nucleosynthesis, with further suppression at later times. Uncertainties arise from relating surface free energy to physical wall energy and from late-time plasma evolution and structure formation. Despite their small energy fraction, these walls could probe the global structure of the SM gauge group, motivating dedicated searches for their cosmological signatures.
hep-phhep-th
11
Quantum Information in High-Energy Physics: a top subject
Yoav Afik · Juan Ramón Muñoz de Nova
As a work selected for the Frontiers of Science Award, we present in the Proceedings of the ICBS an overview of how the techniques from the field of Quantum Information (QI) can be implemented in High-Energy Physics (HEP), including also some novel insights. We focus on the paradigmatic case of the top quark, a drosophila of a relativistic qubit. We study the presence of entanglement, perhaps the most genuine feature of Quantum Mechanics, in top-antitop quark production in high-energy colliders such as the LHC. We also analyze our experimental proposal of a quantum tomography protocol for the top-antitop quark pair, eventually leading to the entanglement observations by the ATLAS and CMS collaborations, which constituted the highest-energy observations of entanglement ever. We discuss how the concepts and techniques developed in our work have effectively spawned an already vast and rich field of QI in HEP.
hep-phhep-exhep-thquant-ph
12
Fractional anomalous determinants and the chiral phase transition
Robert D. Pisarski
At high temperature instantons form a dilute gas, so in QCD-like theories the breaking of the anomalous $U (1)_{A}$ symmetry is given by integral powers of the anomalous determinant, $\sim (det Φ)^{Q}$ , where $Φ \sim q_{L} q_{R}$ is bilinear in the quark fields, and with untwisted boundary conditions, the topological charge, $Q$ , is an integer. A syncretic model is constructed, which is manifestly "beyond Landau". In the chiral limit, at temperatures above the chiral phase transition, $T > T_{χ}$ , only integral powers of the anomalous determinant appear. Below $T_{χ}$ , following 't Hooft et al. I assume that the topological charge $Q$ is fractional, as an integer times $1/ N_{c}$ , where $N_{c}$ is the number of colors. I suggest that consequently, fractional powers of the anomalous determinant appear in the chiral effective Lagrangian. For $N_{f}$ degenerate flavors, this generalizes the Witten-Veneziano term, valid for small $N_{f} / N_{c}$ , to arbitrary $N_{f} / N_{c}$ . In this model the chiral phase transition is generically of second order. The two exceptions are for one flavor, where it is probably crossover, and three flavors, where it could well be weakly first order. This can be tested in lattice QCD with $2 + 1$ flavors by comparing the (known) temperature dependence of the difference of the $π^{a}$ and $a_{0}^{a}$ propagators, to the chiral condensate of the strange quark, between $T_{χ}$ and $\sim 2 T_{χ}$ . Analogous measurements are possible for one to four degenerate flavors about $T_{χ}$ . Lastly, I propose an operator for baryon number in the symmetric phase.
hep-phcond-mat.str-elhep-lathep-th+1
13
Glueballs and fractional anomalous determinants at nonzero $θ$ , and the decays of the X(2370)
Francesco Giacosa · Shahriyar Jafarzade · Győző Kovács · Péter Kovács · Robert D. Pisarski · Fabian Rennecke
Using fractional anomalous determinants, we construct a model of the trace and axial anomalies of a $S U (3)$ gauge theory at nonzero $θ$ angle through the couplings to scalar and pseudoscalar glueballs. In the pure gauge theory, we reproduce the $θ$ dependence of the vacuum energy and the scalar-glueball mass from the lattice, and estimate the jump in the topological charge density for the first-order transition at $θ = π$ . In QCD, the coupling of a pseudoscalar glueball to fractional anomalous determinants describes all of the four three-pseudoscalar decay channels of the $0^{-+}$ glueball candidate $X (2370)$ measured by the BESIII collaboration. Measuring the decay rates for $η η η$ and $η η η^{'}$ can provide a stringent test of the model.
hep-phhep-lathep-thnucl-th
14
A massive right-handed sterile neutrino in three-body $B ˉ \to D^{*} ℓ^{-} N ˉ_{R}$ decays - a Monte Carlo simulation study
Bhubanjyoti Bhattacharya · Thomas E. Browder · Lucien M. Cremaldi · Horacio Crotte Ledesma · Nilakshi Das · Alakabha Datta · Tejhas Kapoor · Kumar Pandey · Alexei Sibidanov
We investigate the differential decay distributions of $B ˉ \to D^{*} ℓ^{-} N ˉ_{R}$ , where $N_{R}$ is a heavy right-handed neutrino (RHN) and $ℓ = e, μ$ . We employ a newly developed Monte Carlo event generator based on the EvtGen framework that can simulate beyond-the-Standard-Model processes. We validate the implementation of the model by comparing the Monte-Carlo results with analytical results for several kinematic variables such as $q^{2}$ and missing mass, as well as signatures in the angular distributions such as $A_{F B}$ , $S_{3}$ , $S_{5}$ , etc. This MC Generator will enable new experimental searches for RHNs. We discuss the sensitivity of various observables to the presence of an RHN and the feasibility of an experimental analysis at Belle II.
hep-ph
15
Unified description of longitudinal and transverse parton dynamics in cold nuclear matter
Weiyao Ke
We present a unified description of longitudinal momentum evolution and transverse-momentum broadening in cold nuclear matter using soft collinear effective theory with Glauber gluon interactions (SCET $_{G}$ ). In a finite nucleus, Landau--Pomeranchuk--Migdal interference couples medium-induced energy loss to the transverse scale resolved by the observable. Our framework combines RG evolution of impact-parameter-dependent energy loss with BFKL-type rapidity evolution of the collision kernel, improved by kinematical constraints and running coupling. With a common set of cold-nuclear-matter parameters, it accounts for the main nuclear modification patterns in semi-inclusive DIS and Drell--Yan production and provides predictions for TMD hadron multiplicities at the EIC. We also discuss the one-point energy correlator in DIS, whose energy weighting suppresses the leading final-state energy-loss contribution. In the EIC kinematics studied, the residual dynamical corrections are small, leaving the nuclear modification dominated by the initial-state nuclear parton distributions.
hep-phnucl-th
16
Charged scalar portal dark matter with $U (1)_{Y}$ non-restoration and gravitational waves
Debasish Borah · Dhruv Ringe · Indrajit Saha
We explore the possibility of reviving scalar singlet dark matter (DM) with a minimal extension by a charged singlet scalar which also leads to hypercharge non-restoration in the early Universe. The minimal scalar singlet DM annihilating via the Higgs portal is tightly constrained by direct-detection experiments, leaving a desert between two narrow regions of the DM mass near the Higgs resonance and around a TeV. The addition of a charged scalar portal revives this desert region while keeping the one-loop direct-detection rate within reach of current and future experiments. A non-zero vacuum expectation value of the charged scalar at high temperature can also drive $U (1)_{Y}$ hypercharge symmetry non-restoration in the early Universe. In a subset of the parameter space, the charge-breaking minimum gets restored to the standard Higgs minimum via a strong first-order phase transition, making it a viable scenario for the generation of baryon asymmetry of the Universe via leptogenesis. A large part of the parameter space consistent with DM relic, direct-detection, symmetry non-restoration and other experimental bounds can be probed at upcoming GW detectors such as LISA, BBO and DECIGO.
hep-ph
17
Inelastic Dark Matter from a Higher-Dimensional Operator: The LUX-ZEPLIN High-Recoil Event and Thermal Relic
Debajyoti Choudhury · Jaydeb Das · Divya Sachdeva
The recent LUX-ZEPLIN (LZ) data shows a nuclear-recoil event around $248 keV$ , motivating scenarios in which dark matter (DM) preferentially scatters at large recoil energies. We investigate an inelastic scattering interpretation in terms of a simple extension with a fermionic DM field interacting with the Standard Model through a single dimension-6 operator. A tiny soft symmetry breaking term facilitates an endothermic transition while naturally suppressing elastic scatterings. Without any fine tuning, a simultaneous explanation of the LZ data and the observed relic density can be effected for a DM mass in the $\sim (0.2, 1)$ TeV range.
hep-ph
18
Neutrino trident process at a muon collider
Reinaldo Francener · Victor P. Goncalves
A TeV-scale muon collider enables the production of a highly collimated high-energy neutrino flux by muon decay in the straight sections of the collider ring. Recent studies have demonstrated that these neutrinos can be used for high-precision measurements in neutrino physics with a dedicated far-forward neutrino detector. In this study, we investigate the potentiality of the muon collider to discover the rare neutrino trident process, which is characterized by the fusion between a weak boson from the neutrino and a photon from the Coulomb field of the nucleus target. Our results indicate large neutrino trident rates per year [ $O (1 0^{3})$ ] in a baseline 10 kg neutrino detector for a configuration of different flavour pairs of charged leptons in the final state, which will allow high-precision tests of the Standard Model and searches for New Physics. As a first example, we investigate the impact of the a new gauge boson $Z^{'}$ , as predicted by the $L_{μ} - L_{τ}$ model, and derive the projected sensitivity to this new gauge boson. Our findings show that a neutrino detector at a muon collider will significantly extend the current excluded regions of the parameter space.
hep-phhep-ex
19
Systematic Bayesian investigation of the (2+1)-flavor QCD phase transition in a holographic model
Liqiang Zhu · Xun Chen · Kai Zhou · Hanzhong Zhang · Mei Huang · Enke Wang
In this study, we construct a bayesian holographic QCD model by integrating the Einstein-Maxwell-Dilaton (EMD) framework with lattice quantum chromodynamics (QCD) data at zero chemical potential, specifically entropy, the square of the speed of sound, and baryon number susceptibilities, while systematically incorporating error estimates from the lattice QCD (LQCD) results. Leveraging a bayesian inference framework, we first achieve a precise calibration of the model parameters, then perform a comprehensive investigation into the thermodynamic properties of $(2+1)$-flavor QCD at both zero and finite chemical potentials, and finally provide a prediction for the location of the critical end point (CEP) in the QCD phase diagram. Our results indicate that, under the maximum a posteriori (MAP) estimation, the CEP is located at $(T, μ)_{MAP} = (0.119, 0.615) GeV$ . Furthermore, we provide the predicted regions for the CEP at $68%$ and $95%$ confidence levels (CL), yielding $(T, μ)_{68% CL} = (0.1176 - 0.1204, 0.59 - 0.63) GeV$ and $(T, μ)_{95% CL} = (0.1172 - 0.1206, 0.58 - 0.63) GeV$ , respectively. A thorough comparison with predictions from other theoretical models validates the robustness and predictive power of our approach. This work not only establishes a novel analytical framework for holographic modeling but also provides valuable theoretical insights into the phase transitions of strongly interacting matter under extreme conditions.
hep-ph
20
Analyticity Bootstrap of Feynman Integrals
Xiang Li · Dao-Ming Mu · Yan-Qing Ma
We propose an analyticity bootstrap method to determine the reduction of Feynman integrals (FIs). The key observation is that, at any kinematic point, a dimensionally regularized FI possesses a Taylor expansion region (analytic region), and the finiteness of the Taylor region strongly constrains the integral reduction coefficients, which are rational functions of the kinematic variables. By writing the most general ansatz compatible with the singularity structure and then fixing the remaining parameters with only a few integration-by-parts (IBP) samples or asymptotic expansions, one can obtain the full reduction. We develop the method systematically in both single-variable and multi-variable cases, with many explicit examples. Interestingly, the differential equations (DEs) of the master integrals determine all these analyticity constraints and, conversely, the constraints facilitate the construction of the DEs. In particular, we show that the DEs in the auxiliary mass flow method can be constructed at significantly reduced cost and can even be fully determined without using IBP.
hep-phhep-th
21
Parton-shower and fixed-order QCD effects in Higgs boson production in weak-boson fusion and its decays to bottom quarks
Arnd Behring
We study the impact of higher-order QCD corrections on Higgs production via weak-boson fusion with subsequent decays of the Higgs boson to bottom-quark pairs. We consider realistic fiducial cuts and observe large corrections in a fixed-order calculation. They arise from the interplay of the particular fiducial cuts considered and the radiative corrections to the Higgs decay subprocess. Switching to a parton-shower-matched description of the decay captures a significant portion of the corrections already at the lowest order and improves the perturbative convergence of the calculation.
hep-ph
22
Gravitational D-form factors of the nucleon and pion with mixing between two-quark and four-quark states
Mamiya Kawaguchi · Yao Ma · Yong-Liang Ma
We investigate the gravitational $D$ -form factors of the nucleon and pion within an extended linear sigma model (eLSM) that incorporates both two-quark and four-quark states, as well as nucleon fields. Within the scalar-meson-dominance picture, we find that meson mixing between two-quark and four-quark states suppresses the nucleon $D$ -form factor and leads to agreement with the lattice-QCD results. Interestingly, a quantitatively similar suppression was previously found in the parity doublet model (PDM) as a consequence of a nonzero chiral invariant component of the nucleon mass. This suggests that the effects of meson mixing and the chiral invariant mass are difficult to distinguish from the nucleon $D$ -form factor alone. We therefore examine the pion $D$ -form factor in the chiral limit. While its value in the forward limit remains fixed at $- 1$ in both the eLSM and the PDM, meson mixing modifies its momentum-transfer dependence. In contrast, the chiral invariant mass does not directly affect the pion $D$ -form factor. These results suggest that a combined analysis of the nucleon and pion $D$ -form factors can provide further insight into the mass decomposition of the nucleon and the quark composition of mesons.
hep-phhep-latnucl-th
23
Probing an up-phobic Higgs at colliders: the role of $b$ -associated production in the democratic 3HDM
Dipankar Das · Teesha Khandelwal · Ipsita Saha
We show that there exists a theoretically well-motivated Higgs sector in which the conventional heavy-Higgs production mechanisms are suppressed. In this limit, the $b$ -associated production channel assumes the role of the primary production mechanism. We demonstrate that the democratic three Higgs-doublet model (3HDM) provides a viable beyond the SM (BSM) framework in which this limit can be realized. We further show that existing $b$ -associated searches provide the most sensitive LHC probe of this 3HDM scenario in the up-phobic limit and derive the corresponding constraints on its parameter space. We also present projections for future collider searches, demonstrating their potential to probe further regions of the model's up-phobic parameter space.
hep-phhep-ex
24
Mechanisms of $D D ˉ$ pair production in $e^{+} e^{-} \to e^{+} e^{-} D D ˉ$ and $AA \to AA D D ˉ$ reactions and production of exotic charmonia
Antoni Szczurek · Izabela Babiarz · Piotr Lebiedowicz · Wolfgang Schäfer
We discuss mechanisms of $D D ˉ$ pair production in $e^{+} e^{-}$ collisions. We consider the $D^{0} D ˉ^{0}$ -continuum mechanism with the $t / u$ -channel $D^{*}$ vector-meson exchanges, where the $D^{*} D γ$ coupling constants are derived from the $D^{*} \to D γ$ decays. For the $D^{+} D^{-}$ channel, we consider mainly the $D^{\pm}$ exchanges. We find a relatively large continuum contribution for the $D^{0} D ˉ^{0}$ channel and a significantly smaller one for $D^{+} D^{-}$ , concluding that the broad bump at $M_{D^{0} D ˉ^{0}} = 3.8$ GeV observed by the Belle and BaBar Collaborations has a continuum origin rather than corresponding to the broad $χ_{c 0} (3860)$ resonance. We also investigate the resonant production of $D D ˉ$ pairs, including $χ_{c 0} (3860)$ and $χ_{c 2} (3930)$ . The $χ_{c 2} (3930)$ meson is a good candidate for the first excited $P$ -wave charmonium $χ_{c 2} (2 P)$ state. This resonance can decay into both $D D ˉ$ channels; however, its branching fractions are not well known at present. Comparing our model result with $Γ (χ_{c 2} (2 P) \to γ γ) = 0.544$ keV (corresponding to the Buchmüller-Tye potential) to the BaBar data, we find $B (χ_{c 2} (3930) \to D D ˉ) = 0.58 \pm 0.13$ . We present results for differential distributions in several variables for Belle II kinematics. Finally, we shortly mention predictions for the ultraperipheral heavy-ion reaction $P b P b \to P b P b D D ˉ$ for low invariant mass ( $M_{D D ˉ} < 4.3$ GeV) at the LHC.
hep-phhep-ex
25
Radiative corrections to the subprocess of annihilation of quark-antiquark pair of prompt photon production in proton-proton collisions at NICA energies $s$ = 10 GeV
Mohsun R. Alizada · Azar I. Ahmadov
In this work, a comprehensive theoretical and numerical study of the quantum-chromodynamic and quantum-electrodynamic radiative corrections: 1. $q q ˉ \to q q ˉ γ$ , 2. $q q ˉ \to g g γ$ , and 3. $q q ˉ \to g γ γ$ to the annihilation of a quark-antiquark pair $q q ˉ \to g γ$ of prompt photon production in proton-proton collisions at NICA energies $s$ = 10 GeV was performed. The differential cross-sections and double spin asymmetries $A_{LL}$ of the radiative corrections were investigated analytically using the FeynCalc and modulated in PYTHIA 8.316. Radiative corrections are significant at low collision energies of protons $s$ and small transverse momentum of photons $p_{T}$ . It was shown that radiative corrections to the annihilation of a quark-antiquark pair process satisfy the following relations: $2. σ_{s} (q q ˉ \to g g γ) > 1. σ_{s} (q q ˉ \to q q ˉ γ) > 3. σ_{s} (q q ˉ \to g γ γ)$ $1. \frac{d σ ( q q ˉ \to q q ˉ γ )}{d p _{T}^{2}} > 3. \frac{d σ ( q q ˉ \to g γ γ )}{d p _{T}^{2}} > 2. \frac{d σ ( q q ˉ \to g g γ )}{d p _{T}^{2}}$ The polarization of colliding protons has almost the same effect on processes 1. $q q ˉ \to q q ˉ γ$ , 2. $q q ˉ \to g g γ$ , and 3. $q q ˉ \to g γ γ$ and in this case above indicated relation is also satisfied. A direct comparison between strict leading order analytical calculations in FeynCalc and PYTHIA 8.316 modulations revealed excellent agreement in the central kinematic regions.
hep-ph
26
From the LZ Event to Grand Unification: Heavy Higgsinos and Proton Decay
Shihwen Hor · Natsumi Nagata · Tsutomu T. Yanagida
The recently reported LUX-ZEPLIN (LZ) event has renewed interest in inelastic Higgsino dark matter. While a weak-scale Higgsino provides a simple interpretation of the event, such a scenario is in tension with the IceCube bound from dark-matter capture and annihilation in the Sun. This tension can be avoided for a much heavier Higgsino, with a mass of order $1 0^{5}$ GeV and a neutral-state mass splitting of $≃ 400$ keV, which in turn points to gaugino masses around $1 0^{7}$ GeV. Such a heavy supersymmetric spectrum is often thought to be unfavorable for supersymmetric grand unified theories (GUTs), since it tends to worsen gauge coupling unification and lower the unification scale, potentially leading to excessively rapid proton decay. In this work, we revisit this expectation in minimal supersymmetric SU(5), taking into account the GUT-scale threshold corrections. We show that the resulting unification conditions allow the SU(5) gauge bosons to remain sufficiently heavy when the adjoint-Higgs self-coupling is small, thereby suppressing dimension-six proton decay. At the same time, the color-triplet Higgs mass can remain near the conventional GUT scale, $M_{H_{C}} \sim 1 0^{16}$ GeV, particularly when the gluino is significantly heavier than the wino. Remarkably, in this region the dimension-five decay mode $p \to K^{+} ν ˉ$ can have a lifetime within the reach of next-generation proton-decay searches, including Hyper-Kamiokande, JUNO, and DUNE. We also discuss supersymmetry-breaking scenarios that can give rise to the required supersymmetric mass spectrum.
hep-ph
27
Overlapping Subcritical Bubbles: Free Energy and Lifetime
Guangshang Chen · Yang Xiao · Jin Min Yang · Yang Zhang
Subcritical bubbles can form an appreciable population during weak first-order phase transitions, but are usually treated as isolated fluctuations. This raises the question of whether spatial overlap between neighboring subcritical bubbles can modify their evolution. We address this question by combining analytic free-energy calculations for composite Gaussian profiles with Langevin simulations of overlapping configurations. We find that the overlap lowers the free-energy cost and generally increases the lifetime of subcritical bubbles, with the enhanced persistence potentially feeding back on their abundance. Such overlap can therefore generate collective effects and should be incorporated into kinetic descriptions of subcritical-bubble populations.
hep-ph
28
Spin relaxation of heavy quarks from momentum diffusion in the quark-gluon plasma
Ankit Kumar · Sourav Dey · Vinod Chandra · Amaresh Jaiswal
Heavy-quark spin dynamics in the quark-gluon plasma provides a potential probe of the interaction between heavy quarks and the medium. We develop a stochastic framework in which the random momentum kicks responsible for heavy-quark diffusion also induce spin rotation through Thomas precession. Starting from the Thomas-Bargmann-Michel-Telegdi equation and a Langevin equation for heavy-quark momentum, we derive a novel coupled spin-momentum Fokker-Planck equation. In the heavy-quark limit, where momentum equilibrates faster than spin, the momentum degrees of freedom can be integrated out, yielding a rotational Fokker-Planck equation for the spin orientation. This establishes a direct relation between the Thomas precession contribution to the spin-relaxation time $τ_{s}$ and the heavy-quark momentum-diffusion coefficient $κ$ . In the non-relativistic limit, we find $τ_{s} = 2 τ_{p} (m_{Q} / T)^{2}$ , with $τ_{p}$ being the momentum relaxation time. Using recent determinations of $κ$ from lattice QCD, strong-coupling estimates, $T$ -matrix calculations, and heavy-flavor phenomenology, we obtain the corresponding Thomas precession contribution to spin relaxation times for charm and bottom quarks. Relativistic kinematics modify the result by only a modest amount over the temperature range relevant for heavy-ion collisions, while the uncertainty is dominated by that of $κ$ . We emphasize that the result represents the Thomas precession contribution to heavy-quark spin relaxation; direct coupling to the chromomagnetic field provides an additional channel.
hep-ph
29
Generalized fluctuation-dissipation theorem and Einstein relation in rotating equilibrium
Shuo Fang · Shi Pu
We derive a generalized fluctuation-dissipation theorem (FDT) for vector fields in rotating thermal equilibrium from an exact phase-space Kubo-Martin-Schwinger (KMS) relation. The resulting FDT contains rotation-induced tensorial contributions beyond a scalar thermal factor. In the local transport limit, we obtain a model-independent generalized Einstein relation with rotation in which, through second order in thermal vorticity, symmetric momentum diffusion depends on low-frequency spectral information beyond that encoded in the rotation-dependent dissipative drag. Remarkably, we find a new Einstein-type relation linking zero modes in the spectral function to the nonrotating drag coefficient. These zero modes underlie a new mechanism for the orbital polarization of heavy quarkonium. The same FDT constraint yields a modified detailed-balance relation whose first-order vortical correction is governed by transition polarization, without explicit dependence on the bath model. Our findings establish microscopic equilibrium constraints for studying rotating quantum matter in various fields.
hep-phcond-mat.stat-mechhep-thnucl-th
30
Probing the neutrino mass through semileptonic decays
Claire Chevallier
We argue that a detailed analysis of semileptonic decays can test the possibility of a massive neutrino. The key observable, related to the forward-backward asymmetry, is exactly zero for a massless neutrino but becomes non-zero if the neutral lepton is heavy and interacts with Standard Model fields via left-handed operators. For right-handed interactions, this quantity differs significantly from zero even for a massless right-handed neutrino. We demonstrate this explicitly using the example of a pseudoscalar meson decaying into another pseudoscalar meson.
hep-ph
31
Near Threshold Kaluza-Klein Graviton Decays and the Dark Dimension
Kevin Langhoff
Near threshold, intra-tower decays of Kaluza-Klein (KK) gravitons are pure $d$ -wave, with rate $Γ \propto p^{5}$ in the decay products momentum $p$ , rather than the $s$ -wave $Γ \propto p$ assumed in the dark dimension literature. In a flat dark dimension this excludes KK gravitons as a dark matter candidate. Even if some other source of dark matter is assumed, the irreducible freeze-in abundance of KK gravitons produce MeV gamma rays which allows one to set upper limits on the reheating temperature; additionally using the lower bound on the reheating temperature from big-bang nucleosynthesis and the cosmic microwave background requires the radius of the extra dimension to be almost three orders of magnitude smaller than the distance conjecture would naively prefer, $R \sim Λ^{- 1/4}$ .
hep-phhep-th
32
An optimal strategy for experimental searches in high-mass dilepton production at the LHC
J. Alcaraz Maestre · O. M. Carretero
We present an optimal method for studying new physics effects in high-mass dilepton production at the LHC. This method relies on a reweighting procedure that is precise to the next-to-leading order in quantum chromodynamics. The only computationally expensive input required is a standard model $pp \to V^{(*)} \to ℓ^{+} ℓ^{-}$ sample, with $V = Z, γ^{*}$ , generated at the same level of precision and with sufficient statistical coverage of the phase space at high invariant masses. The proposed method is suitable for any $q q ℓ^{+} ℓ^{-}$ contact-interaction scenario, regardless of the assumed underlying structure and couplings. It is also ideal for searching for medium-to-large-width new neutral resonances produced in the s-channel, as changes to the input values for mass, coupling, or width can be easily implemented using the same initial generated samples.
hep-phhep-ex
33
Confronting $K^{-} d$ dynamics with kaonic atom measurements within a novel unitary framework
Albert Feijoo · Àngels Ramos · Juan Torres-Rincon
We study the low-energy interaction of negative kaons with deuterons using chiral $K ˉ N$ interaction models (OR and BCN) as input. The three-body $K^{-} d$ amplitude is constructed within the Fixed-Center Approximation to the Faddeev equations, where the unitary constraints missing in the conventional approach are formally implemented with the incorporation of coherent multiple-scattering processes. The unitary procedure is extended to coupled channels including charge-exchange processes, as well as isospin-breaking effects through the use of physical particle masses. This provides a consistent description of the low-energy $K^{-} d$ amplitude and allows for the determination of the scattering length and the effective range. The resulting framework is then used to assess the compatibility of the BCN $K ˉ N$ interaction model with the recent SIDDHARTA-2 measurements of kaonic hydrogen and kaonic deuterium through a bootstrap analysis. The procedure leads to a readjustment of the BCN parameterization which produces visible effects in several isospin-sensitive $K ˉ N$ scattering observables, hence highlighting the additional information provided by the new kaonic-atom measurements to better constrain the poorly known isovector component of the $K ˉ N$ interaction.
hep-phhep-exnucl-exnucl-th
34
Effective field theory of scalar glueballs: Form factors and interaction radii
Adamu Issifu · Orlando Oliveira · Tobias Frederico
We develop a gauge-invariant effective field theory for scalar glueball interactions based on the Yang-Mills gluon condensate. Starting from a coherent-state formulation of the Yang-Mills vacuum, we derive an effective Lagrangian for the scalar glueball and its interactions with gluons. The resulting crossing-symmetric amputated four-gluon Green's function is projected onto the color-singlet $J^{P C} = 0^{++}$ channel, yielding a normalized scalar glueball form factor that factorizes into universal kinematic structures and an intrinsic glueball function. The formalism predicts a parameter-free effective interaction radius for the ground-state scalar glueball with resonance $f_{0} (1710)$ , $r_{int} = 6 / m_{ϕ} = 0.28$ fm, which is in excellent agreement with recent lattice Yang-Mills determinations of the mass-radius ( $r = 0.263 (31)$ fm). The predicted momentum dependence of the normalized form factor is consistent with lattice Yang-Mills gravitational form factor data, with the $f_{0} (1710)$ candidate providing the best overall fit and $r_{int}$ . Inclusion of the first excited $0^{++}$ glueball produces modest corrections to the interaction radius ( $r_{int}^{*} = 0.240$ fm) while yielding stable and kinematically robust modifications of the form factor. This framework provides a systematic bridge between effective field theory and first-principles lattice Yang-Mills calculations of scalar glueball dynamics.
hep-phhep-lathep-th
35
Electron and monopole properties in a dark matter model
Jacob García-Moreno · Vicente Vento
Monopoles have been a subject of much theoretical and experimental research since they were proposed to symmetrize Maxwell's equations. No experimental signature of their existence has been detected. A model generalizing QED with dark massless photons and dark monopoles was proposed not long ago. In this model, by introducing a mixing interaction between the two sectors, leptons and monopoles are transformed into into dyons. This particular behavior of the electrons determines a new path to study the physics of monopoles. Here we generalize the Electroweak theory in the same way by incorporating a dark sector with massive photons and monopoles, and analyze experimental consequences for electrons in both models. The mass of the dark photon plays an important role regarding observability.
hep-ph
36
A consistent $O (v^{2})$ NRQCD description of decays and high- $P_{T}$ prompt production of charmonia
Valerio Bertone · Jean-Philippe Lansberg · Kate Lynch · Tanjona R. Rabemananjara
We present a global determination of the six long-distance matrix elements (LDMEs) within non-relativistic QCD (NRQCD) appearing in the production of prompt $J / ψ$ up to $O (v^{2})$ using high- $P_{T}$ LHC data for direct and feed-down contributions from $χ_{c}$ and $ψ (2 S)$ . Using a leading-power fragmentation framework at NLO+NLL, we fit $ψ (2 S) / J / ψ$ yield ratios from ATLAS and CMS and $ψ (2 S)$ CMS polarization data at $s = 13$ TeV, injecting one decay width per charmonium. The fit LDMEs provide excellent predictions of the CMS and ATLAS cross-section data up to $P_{T} = 360$ GeV for the $J / ψ$ , as well as the $J / ψ$ polarization data from CMS. The obtained excellent agreement with production and decay data demonstrates that $O (v^{2})$ NRQCD is sufficient to describe $J / ψ$ , $ψ (2 S)$ , and $χ_{c}$ hadroproduction at large $P_{T}$ .
hep-phhep-exhep-th
37
The Scalar MSW Effect: Compact analytical formulas for neutrino oscillations with large matter effects, including $μ - μ$ and $τ - τ$ dominant matter potentials
Sandhya Choubey · Andreas Lund
Deriving simple and accurate three-flavor neutrino oscillation probability formulas in matter is critical for understanding the phenomenology of upcoming experiments. In this article, we extend the Jacobi diagonalization method for deriving effective parameter mappings for neutrino oscillations in matter. The key insight behind the extension is to purposefully parameterize the mixing matrix, $U_{PMNS}$ , using particular arrangements of Euler rotations. This novel extension allows for deriving simple and accurate effective mixing parameter mappings for exotic types of matter potentials. First, we revisit the Jacobi diagonalization method for neutrino oscillations with standard matter effects and use this to demonstrate our generalization. Subsequently, we apply the Jacobi diagonalization method to scalar non-standard interactions (SNSI) and derive effective parameter mappings for all three single diagonal coupling cases. The resulting formulas reveal that all diagonal SNSI couplings could give rise to a scalar MSW (SMSW) effect, that is an energy independent resonant enhancement analogous to the MSW effect. Finally, we study the accuracy of the derived SNSI formulas for various contemporary and upcoming experiments. For $δ m_{ee}$ , the accuracy is excellent for all considered experiments. For $δ m_{μμ}$ and $δ m_{τ τ}$ the accuracy is worse since $A_{C C}$ must be neglected, and first order perturbative corrections are applied to amend this.
hep-phhep-exhep-th
38
Drell-Yan lepton pair production from low to high transverse momentum
Benoît Assi · Enrico Bothmann · John Campbell · Christian Gütschow · Stefan Höche · Wan-Li Ju · Max Knobbe · Marek Schönherr · Jesse Thaler · Michael L. Wagman
We present a technique for computing Drell-Yan lepton pair production at particle-level that achieves N $^{3}$ LO and approximate N $^{4}$ LL $^{'}$ accuracy at small to moderate transverse momentum, tree-level precision for $Z + 4$ , $5$ , and $6$ jets, and approximate NLO EW precision at high transverse momentum. A crucial non-perturbative input, the Collins-Soper kernel, is obtained from continuum-limit lattice QCD results. High-precision theory results are recast into strictly positive event weights using an information-theoretic approach based on the maximum entropy principle.
hep-phhep-exhep-lat
39
Close Pulsar Pairs See Dark Matter Substructure through the Gravitational-Wave Background
Abhiram Cherukupalli🇺🇸 · Vincent S. H. Lee🇺🇸 · Kim V. Berghaus🇩🇪 · Kathryn M. Zurek🇺🇸
Pulsar timing arrays detect signals from dark matter substructure, but a nanohertz gravitational-wave background (GWB) severely degrades their sensitivity. We show that timing pulsar pairs separated by sub-parsec distances avoids this degradation. The GWB imprints nearly the same perturbation on both pulsars and is suppressed in the difference of their residuals, whereas a nearby dark matter subhalo perturbs the two differently and survives. We find that an array with pulsar pairs separated by $0.1 pc$ improves the sensitivity to subhalos of order $\sim 1 0^{- 6}$ solar masses by more than an order of magnitude, relative to an otherwise identical array of widely separated pulsars. Dense globular clusters naturally host many such pairs, though the baryonic environment must be separated from a dark matter substructure signal.
↳ astro-ph.COhep-ph0 citations
40
Neutrino Oscillations without Mass: A Re-analysis of KamLAND Data following the Dirac Equation in Curved Spacetime
Golam Mortuza Hossain🇮🇳 · Pushpit Kumar🇺🇸
The Dirac equation in stationary curved spacetime implies that describing two-flavor neutrino oscillations requires treating the invariant mass and conserved energy of each propagating state distinctly, as gravity affects energy differently than mass. By re-analysing the publicly released KamLAND dataset, we show that modeling flavor states of massless neutrinos as two-level quantum states with energy-dependent level splitting, analogous to modified Jaynes-Cummings models, results in a higher-likelihood fit to the observed data than the standard massive-neutrino paradigm.
↳ gr-qchep-phhep-th0 citations
41
No-signaling-in-time condition for three-flavor neutrino oscillations
Massimo Blasone · Fabrizio Illuminati · Luciano Petruzziello · Kyrylo Simonov · Luca Smaldone
Macrorealism is a fundamental concept in quantum foundations, capturing basic features of our everyday experience. Among the main tools introduced to test violations of macrorealism are the Leggett-Garg inequalities. These inequalities provide necessary and sufficient conditions for a certain data set including the correlators measured in a number of different experimental runs (weak version of macrorealism). Leggett-Garg inequalities have proved useful for detecting violations of macrorealism in neutrino oscillation experiments. However, it is interesting to investigate a set of necessary and sufficient conditions for strong macrorealism - no-signaling-in-time and arrow-of-time conditions - in order to obtain a more complete characterization of macrorealism in the context of neutrino oscillations. In particular, here we extend previous study of the no-signaling-in-time condition to the case of three-flavor neutrino oscillations, including the CP-violating phase of the Pontecorvo-Maki-Nakagawa-Sakata matrix.
↳ hep-thhep-phquant-ph
42
Gaugino condensates in $N = 1$ super-Yang-Mills Theory on Eguchi-Hanson space
Mohamed M. Anber
We study gaugino condensates in $N = 1$ $S U (N)$ super-Yang--Mills theory on Eguchi--Hanson space using instanton methods. Fractional topological charge and the spectral asymmetry of the asymptotic $RP^{3}$ boundary modify the instanton calculus. A charge- $\frac{1}{2}$ instanton carries only two adjoint gaugino zero modes and can therefore contribute directly to the bilinear. Because the Eguchi--Hanson path integral prepares a boundary state on $RP^{3}$ , the observables are boundary-sector-projected amplitudes. Moreover, supersymmetric Ward identities ensure that chiral correlators are independent of insertion points and the Eguchi--Hanson resolution parameter. For $S U (2)$ instanton, with central holonomy, the full collective-coordinate integral gives $⟨ tr (λλ)⟩ = 16 π^{2} Λ^{3}$ for a specified boundary projection, reproducing the flat-space value. For a single $S U (2)$ -block embedding in $S U (N > 2)$ , the noncentral holonomy requires a continuum determinant for renormalization-group invariance, so zero modes alone do not determine the bilinear. We also study a charge- $1$ $S U (4)$ two-block saddle with central holonomy, $16$ bosonic moduli, and $8$ adjoint zero modes. Its collective-coordinate integral gives $⟨ \prod_{i = 1}^{4} tr (λλ) (x_{i})⟩ = \frac{1}{6} (16 π^{2} Λ^{3})^{4}$ . Under the assumptions required for position independence and clustering, this result determines the fourth power of the bilinear condensate in the corresponding boundary sector. Since no independent bilinear calculation is available in the same sector, the factor $1/6$ does not by itself constitute a clustering puzzle.
↳ hep-thhep-phmath-phmath.MP
43
Scaling Collider Event Generation with Residual-Quantized Tokens
Dan Godi · Dmitrii Kobylianskii · Eilam Gross
Full detector simulation and reconstruction of collider events are projected to become major bottlenecks at the High-Luminosity Large Hadron Collider, motivating the development of fast, ML-based surrogates. At the same time, LLMs have driven fast progress in generative discrete modeling: autoregressive transformers trained on tokenized data now represent the state of the art across a range of generative tasks. We extend the discrete modeling paradigm by introducing a particle-level generative model trained on residual-quantized full-event data. We demonstrate the ability of this model family to perform conditional generation from detector-stable particles; we study its scaling behavior across a range of dataset and model sizes, characterize the effects of repeated data exposure and demonstrate that token-level loss systematically predicts downstream physical fidelity. These results provide an empirical framework for scalable collider full-event generation based on residual-quantized representations.
↳ hep-excs.LGhep-phphysics.data-an
44
Absence of Continuous Spin Particles in Superstring Theory
Arwa Alabbasi · Fernando Quevedo
The study of continuous spin particles, as general low-energy implications of relativity and quantum mechanics, has intensified in recent years with potential experimental signatures. In this note we show that these particles are absent in perturbative super-string theories, generalising a result in arXiv:1302.4771 to the supersymmetric case. This stands out as a general low-energy prediction of all perturbative superstring constructions.
↳ hep-thhep-ph
45
Towards Retrieval Augmented Generation in High-Energy and Astroparticle Physics
Jacky Kumar · Sajan Kumar
The high-energy and astroparticle physics literature has grown into an enormous body of knowledge. Gaining a comprehensive understanding of this literature is an important step in research, but is a challenging task. Before making meaningful advances, it is important to establish what has already been done and identify open questions. However, this process is becoming increasingly difficult given the sheer volume of publications. Conducting a focused literature survey on a narrow topic is particularly challenging. We develop an open-source Retrieval Augmented Generation (RAG) pipeline to produce concise, targeted summary reports with citations, grounded in the database of arXiv papers, enabling researchers, editors, and referees to rapidly orient themselves within any corner of the field. Specifically, we embed approximately 230K hep-ph and astro-ph.HE papers to enable a hybrid retrieval that captures both keyword matches and semantic similarity. The fused candidate set is then refined using a cross-encoder reranker. Following retrieval, the papers are passed to a Large Language Model (LLM), for which we use Google DeepMind's open-source Gemma-4-E4B model. The LLM first acts as a judge to evaluate the relevance and then synthesizes a coherent and grounded report with references. This modern AI-driven approach allows us to go beyond the capabilities of classical keyword search on arXiv or Inspire-HEP.
↳ astro-ph.HEhep-ph
46
High-energy neutrinos from shocked circumnuclear material around optically-bright and infrared-only tidal disruption events
Mainak Mukhopadhyay · Shigeo S. Kimura · Tatsuya Matsumoto
Tidal disruption events (TDEs) can launch sub-relativistic outflows that drive shocks into the surrounding circumnuclear material (CNM), providing a natural site for cosmic ray (CR) acceleration and high-energy neutrino production through hadronuclear ( $pp$ ) interactions. We model this emission for optically bright and infrared (IR)-only TDEs, the latter motivated by a recently identified population of luminous IR transients with weak or absent optical counterparts, consistent with TDEs embedded in dusty, obscured nuclear environments. We semi-analytically compute the shock dynamics, CR acceleration and transport, and neutrino production, including the radiative cooling and compression in dense environments. While optical TDEs remain inefficient $pp$ neutrino sources with comparatively small neutrino yields, radiative compression in dense IR-only TDEs enhances the target density and allows the pp efficiency to approach the calorimetric regime, yielding up to $\sim 10%$ of the observed diffuse neutrino flux at $100$ TeV, given the rate uncertainties. The long-lasting neutrino emission and low individual source yield motivate joint electromagnetically informed stacking searches. We forecast such searches for IceCube, IceCube-Gen2, KM3NeT, and HUNT, and conclude that a future $\sim 30 k m^{3}$ neutrino observatory can reach $3 σ$ sensitivity for nearby ( $z ≲ 0.4$ ) IR-only TDEs with multi-year search windows. Growing optical and IR TDE samples can therefore enable population-resolved searches that can test whether dense, obscured nuclear environments are efficient high-energy neutrino sources.
↳ astro-ph.HEhep-ph
47
Microscopic Insights into the Quarkyonic Hadron--Quark Crossover: Lessons from Ultracold Fermi Gases
Hiroyuki Tajima
In neutron-star and dense quantum chromodynamics (QCD) physics, it is important to understand how baryonic matter evolves into quark matter at high density. A continuous hadron--quark crossover is one of the most attractive candidates because it can reconcile the comparatively soft equation of state around nuclear density with the rapid stiffening required to support massive neutron stars. Recent neutron-star observations motivate equations of state that stiffen rapidly across the intermediate-density regime, while quarkyonic-matter descriptions feature a shell-like baryon momentum distribution there. In this paper, we review our recent work on the microscopic description and interpretation of these phenomena by drawing an analogy with the Bose--Einstein condensate (BEC) to Bardeen--Cooper--Schrieffer (BCS) crossover in ultracold Fermi gases and two-color QCD. As pairing fluctuations play a crucial role in the BEC--BCS crossover, we discuss the role of its three-body counterpart, that is, tripling fluctuations associated with baryon formation in the hadron--quark crossover. In terms of a phase-shift representation of tripling fluctuations, the interplay between a three-body bound-state pole and the scattering continuum suppresses low-momentum baryonic occupation, generates a baryonic momentum shell, and reduces the density susceptibility, thereby producing a peak in the speed of sound. We review the demonstration of this mechanism in a one-dimensional three-component Fermi gas, its relativistic extension, and its connection to phenomenological quarkyonic equations of state.
↳ nucl-thcond-mat.quant-gashep-ph
48
Hadronization into Nuclei: Does Size Matter?
Anton Andronic · Peter Braun-Munzinger · Hjalmar Brunßen · Johanna Stachel
We investigate an extension of the statistical hadronization model (SHM) that takes (hyper)nucleus sizes into account. The spatial extent of nuclear wave functions relative to the fireball volume is used to calculate a size correction, which describes the suppression with respect to a point-like treatment of the (hyper)nucleus at hadronization. For several species of light nuclei (d, $^{3} H$ , $^{3} He$ ) and for the hypernucleus $_{Λ}^{3} H$ , the predicted effects of the size correction on SHM yields are compared to yield measurements in pp, p-Pb, and Pb-Pb collisions in the ALICE experiment. The experimental data suggest that this size correction, based on applying final-state wave functions at chemical freeze-out, does not give a consistent description of (hyper)nucleus production in nuclear and hadronic collisions. By contrast, the SHM without a nuclear-size correction provides a substantially better description of the data. This result lends further support to the interpretation that such nuclear states are formed from initially compact (multi-quark) configurations which after hadronization expand to their final-state wave functions.
↳ nucl-thhep-ph
49
A celestial viewpoint on infrared divergences in QCD
Lorenzo Magnea · Enrico Zunino
Non-abelian infrared radiation can be seen as both a practical ingredient for QCD phenomenology and a window on the long-distance structure of gauge theories. During the last decade, a novel viewpoint was developed on infrared phenomena: soft currents are seen as arising from asymptotic symmetries realised on the celestial sphere, and soft colour correlations similarly emerge from a two-dimensional conformal field theory on the sphere. In this contribution, we briefly review the status of this approach. We begin with the standard bulk picture, presenting the infrared factorisation of massless scattering amplitudes, and then we show how universal infrared information gets mapped to marked points on the celestial sphere. In particular, soft colour-dipole singularities are reproduced to all orders by a correlator of vertex operators in a free-boson theory on the sphere. We then proceed to study soft-gluon currents, and show how bulk results constrain the structure of the celestial theory beyond the free-field limit. For single emission, we note that all logarithms in dipole-like loop contributions can be absorbed into the choice of scale for the strong coupling. For multiple emission, we show how the emerging mixed-helicity celestial operator product expansion must be weighted by energy fractions, breaking holomorphic factorisation and obstructing associativity under successive collinear limits. These results illustrate a remarkable connection between the familiar physics of infrared QCD and the dynamics of a two-dimensional theory on the celestial sphere.
↳ hep-thhep-ph
50
Tree-Level Interaction Vertices in the Linear Sigma Model with Quarks under Global Rotation
Luis A. Hernández · Eduardo Lazcano · R. Zamora
We derive the tree-level interaction vertices of the linear sigma model with quarks in the presence of global rotation. Starting from the scalar and fermionic field solutions in a rotating background, we construct the corresponding spectral representations and use them to evaluate the mesonic self-interactions and Yukawa couplings of the model. We show that rotation modifies the usual momentum-space structure of the interaction vertices: conservation of longitudinal momentum is accompanied by angular-momentum selection rules, while the transverse dynamics is encoded in rotation-induced radial form factors involving products of Bessel functions. The resulting expressions provide a set of interaction rules adapted to the symmetries and finite geometry of the rotating system. Although derived within the linear sigma model with quarks, the structures obtained for scalar self-interactions and scalar-fermion couplings can be extended to a broader class of quantum field theories under global rotation. These results provide the building blocks for perturbative calculations and contribute toward a microscopic quantum-field-theoretical description of interacting matter in rotating environments.
↳ hep-thhep-ph
51
Trace-anomaly decomposition and universal dark matter scaling in compact stars
Adamu Issifu · Constança Providência · Tobias Frederico
We investigate how dark matter (DM) admixture modifies the conformal properties and phase structure of dense neutron-star matter within a self-consistent single-fluid framework, with the global DM fraction $F_{χ} = N_{χ} / N_{B}$ fixing the local relation $n_{χ} = F_{χ} n_{B}$ . We derive an exact decomposition of the total trace anomaly, $Δ_{tot}$ , into microscopic contributions. For collider-motivated Higgs-portal benchmarks, explicit Higgs, vector-mediator, and contact-interaction contributions are negligible, while heavy nonrelativistic DM has an intrinsic trace anomaly close to the nonrelativistic limit, $Δ_{χ} ≃ 1/3$ . Consequently, the DM rest-mass energy fraction dominates the DM-induced modification of $Δ_{tot}$ , producing a smooth upward shift of up to $\sim 0.1$ for $F_{χ} \sim 0.2%$ . In the pressureless, comoving heavy-WIMP regime, we further identify a universal dark-sector scaling governed by the mass-loading parameter $λ = F_{χ} m_{χ} / m_{N}$ : numerical calculations with different $(F_{χ}, m_{χ})$ pairs at fixed $λ$ exhibit overlapping trace-anomaly, sound-speed, and mass--radius responses for a given baryonic equation of state. In hybrid stars, DM leaves the coexistence pressure and chemical potential essentially unchanged, whereas first-order hadron--quark deconfinement produces sharp discontinuities in the squared sound speed $c_{s}^{2}$ , $Δ_{tot}$ , and $Δ_{tot} - Δ_{B}$ . The combined softening substantially reduces the maximum stellar mass, placing $F_{χ} \sim 0.2%$ in tension with the observed $2 M_{⊙}$ neutron stars. These results show that the trace anomaly and its density evolution provide a sensitive diagnostic for distinguishing smooth DM-induced modifications of dense matter from genuine first-order deconfinement.
↳ nucl-thastro-ph.HEhep-ph
52
Strongly mixed cosmological collider at unequal sound speeds
Javier Huenupi · Gonzalo A. Palma · Spyros Sypsas
We derive the canonically normalized modes of a two-field inflationary system with arbitrary constant quadratic mixing and unequal sound speeds $c_{φ}$ and $c_{σ}$ for the curvature and isocurvature perturbations, respectively. A Laplace representation reduces the coupled dynamics to a second-order Heun equation and gives the exact late-time curvature power spectrum for arbitrary values of the mixing parameter and entropy mass. The sound-speed ratio $r_{c} = c_{σ} / c_{φ}$ controls the separation between the two sound horizons. At fixed nonzero mixing and $r_{c} ≪ 1$ , the power exhibits power-law enhancement, growth as $ln^{2} (1/ r_{c})$ , or bounded oscillations in $ln r_{c}$ , depending on the mass and mixing. For $r_{c} ≫ 1$ , the correction to the unmixed spectrum vanishes as $ln r_{c} / r_{c}^{2}$ at fixed mass and mixing. Using the same normalized modes, we compute the tree-level bispectrum for three representative cubic interactions, with the mixing parameter treated exactly. For heavy entropy fields, unequal speeds modify the collider amplitude and phase while preserving the strict squeezed frequency set by the final entropy mass. The power-normalized amplitude can vary nonmonotonically with $r_{c}$ , and a sound-speed hierarchy can delay the approach to this asymptotic regime.
↳ astro-ph.COhep-phhep-th

Affiliations

first authorsco-authorsvia INSPIRE