HEP Phenomenology·hep-ph

Mon·Oct 12, 2026Monday·October 12, 2026

19 papers—13 primary·6 cross-listed

01
Mass and decay angles in the $Ξ_{c}$ -- $Ξ_{c}^{'}$ mixing tension: Virtual hybrids and a single-direction criterion
Sanghoon Kim · Gihwan Nam · Jongheon Baek
We study the relation between mixing angles obtained from mass calculations and those inferred from decay analyses of the $Ξ_{c}$ -- $Ξ_{c}^{'}$ system. Within a constituent-quark model, we compare three definitions: a spin-component probability angle, a common-source overlap angle, and an SU(3)-breaking mass-operator angle. The probability angle is $3.1 1^{\circ}$ , while the latter two definitions give $2.48$ -- $2.5 8^{\circ}$ ; a second parameter set gives $2.38$ -- $2.4 9^{\circ}$ . The change of definition reduces, but does not remove, the difference from the lattice values $1.2 (1)^{\circ}$ and $0.810 (50) (200)^{\circ}$ . We then include virtual $q s Q g$ states coupled to the conventional $q s Q$ states, where $q = u, d$ and $Q = c, b$ . In the tested orbital- $S$ -wave model, a chromomagnetic transition containing both $j_{Q g} = 1/2$ and $3/2$ raises the source and mass-operator charm angles to $2.67$ -- $3.1 6^{\circ}$ when its strength is normalized to reference short-range mass shifts. The hybrid probability remains below $1.7%$ , and the corresponding bottom angles are $0.42$ -- $0.4 8^{\circ}$ . We also give a single-direction condition for the induced mass correction to be proportional to a single rank-one projector. This condition concerns the mass operator, not a universal angle for decay amplitudes. Eliminating the hybrid sector changes the current operator as well as the Hamiltonian; we derive this relation but do not calculate process-dependent decay angles. The results include projected hyperfine coefficients and energy-cut sums for comparisons in specified continuum and lattice matching schemes.
hep-phnucl-th
02
Seeing in the Dark: Gravitational Waves from Resonant Production of Dark Photon Dark Matter
Yanou Cui · Pankaj Saha · Evangelos I. Sfakianakis
Ultralight dark photons (DPs) are well-motivated dark matter candidates. A promising yet underexplored mechanism for their relic abundance is parametric resonance in the Abelian-Higgs model that generates the DP mass. We advance previous analytical studies through dedicated 3D lattice simulations that capture important nonlinear effects, including backreaction and relic partitioning between the dark Higgs and DPs. We further predict the associated stochastic gravitational-wave (GW) signal, which can be within reach of a broad range of detectors, opening a new avenue to probe ultralight DP dark matter.
hep-phastro-ph.CO
03
Probing $τ$ lepton dipole moments at FCC-ee
Dario Buttazzo · Gabriele Levati · Yang Ma · Fabio Maltoni · Paride Paradisi · ZeQiang Wang
We study the sensitivity of future high-luminosity $e^{+} e^{-}$ colliders to the electromagnetic and weak dipole moments of the $τ$ lepton within the Standard Model Effective Field Theory. We analyse several complementary processes across the FCC-ee operating stages and show that the exceptional luminosity and clean environment of future $e^{+} e^{-}$ colliders allow for substantial improvements over current limits from LEP and the LHC. The $e^{+} e^{-} \to τ^{+} τ^{-}$ process provides excellent sensitivity to weak dipole operators through resonant $Z$ production and $Z$ -pole energy scans, while $γ γ \to τ^{+} τ^{-}$ yields the strongest constraint on the anomalous magnetic moment owing to the dominance of linear interference effects in the near-threshold region. Higher-energy stages improve the sensitivity to the $τ$ electric dipole moment. The radiative processes $e^{+} e^{-} \to τ^{+} τ^{-} γ$ and $H \to τ^{+} τ^{-} γ$ provide complementary, though subleading, probes of $τ$ dipole operators. Combining all channels, we estimate the statistical reach at the 95% CL to be $∣Δ a_{τ} ∣ < 2.8 \times 1 0^{- 5}$ , $∣ d_{τ} ∣ < 2.5 \times 1 0^{- 18} e cm$ , $∣Δ a_{τ}^{Z} ∣ < 1.0 \times 1 0^{- 5}$ , and $∣ d_{τ}^{Z} ∣ < 4.4 \times 1 0^{- 19} e cm$ , improving upon the current bounds by several orders of magnitude. These projections quantify the potential statistical reach of the FCC-ee program, motivating dedicated studies incorporating detector effects, systematic uncertainties, and higher-order theoretical predictions.
hep-phhep-ex
04
A portable implementation of one-loop Feynman integrals
Reet Barik · John M. Campbell · Taylor Childers · Stefan Höche · Max Knobbe
We present the first performance-portable implementation of a loop integral library for high-energy particle physics. The new code is based on the QCDLoop package, which provides an essential component in the software stack for perturbative precision calculations at collider experiments. Our implementation extends QCDLoop to modern computing architectures by means of the Kokkos portability framework, which allows to target most existing CPUs and GPUs.
hep-ph
05
Testing coherent elastic neutrino-nucleus scattering N dependence
Laura Duque · O. G. Miranda · G. Sanchez Garcia
Despite its elusive character, coherent elastic neutrino-nucleus scattering (CEvNS) detection is evolving as a precision measurement from different neutrino measurements. In this note we show how CEvNS experiments using the Spallation Neutron Source (SNS) are robust measurements that enter into a precision era. Despite the interplay of nuclear and elementary particle physics, we demonstrate that CEvNS current measurements are accurately described by using only one extra parameter, the number of neutrons, $N$ . By making this test, we illustrate that current CEvNS are precise enough to reconstruct the number of neutrons in the nuclear target. At the same time, determining the number of nucleons in the target material can be used as a benchmark for the precision and accuracy of this kind of detectors.
hep-phhep-ex
06
Stochastic gravitational waves from narrow-band cosmological magnetic fields
Abdias Aires · Tatsuya Daniel
We calculate the spectrum of gravitational waves generated by a cosmological magnetic field with a narrow-band power spectrum. For a spectrum narrowly peaked at a comoving wavenumber $k_{c}$ , we find that the gravitational wave signal peaks at $2 k_{c}$ and has a sharp cutoff at this scale. We apply this result to an ultralight dark matter model of magnetogenesis operating around recombination, in which an axion-photon coupling generates a helical magnetic field by parametric resonance. We determine the conditions for the resulting gravitational waves to enter the frequency range of pulsar timing experiments. Although the required frequency can be reached for sufficiently large coupling, the corresponding amplitude is below the experimental sensitivity for physically allowed energy densities of the magnetic field. We generalize this conclusion to models of magnetogenesis operating at other epochs, estimating as $T ≃ 160 MeV$ the temperature of a magnetogenesis process assumed to be the source of the stochastic gravitational wave background suggested by pulsar timing arrays. We place the lower bound $T ≳ 1$ - $10 MeV$ on such viable models.
hep-phastro-ph.COgr-qchep-th
07
Undiscovering Quark-gluon Plasma
Thomas A. Trainor
An exploration of the scientific method applied to heavy ion research in comparison to the functioning of large collaborations
hep-ph
08
Direct detection constraints on EFT operators for inelastic dark matter
X. G. Wang · A. W. Thomas
We convert existing exclusion limits on the elastic spin-independent (SI) dark matter--proton cross sections into upper bounds on the event rate, subsequently applying them to constrain other effective operators for inelastic scattering of light dark matter in the GeV mass region. We focus on three representative scenarios including the isoscalar, proton-philic, and the proton-philic spin-dependent inelastic dark matter model, which are well-motivated in phenomenological studies of dark matter detection.
hep-phastro-ph.COhep-ex
09
Predictions for neutron-tagged Coulomb dissociation in ultraperipheral Ru+Ru and Zr+Zr collisions
Huda Nasrulloh · Xinbai Li · Zebo Tang · Kaiyang Wang · Luobing Wang · Xin Wu · Wangmei Zha
The photonuclear response reflects nuclear structure and the dynamics of excitation and decay, with neutron-emission channels retaining information that can be obscured in inclusive dissociation yields. We calculate specified-side and mutual neutron-tagged Coulomb-dissociation cross sections in ultraperipheral $_{44}^{96} Ru +_{44}^{96} Ru$ and $_{40}^{96} Zr +_{40}^{96} Zr$ collisions at $s_{NN} = 200 GeV$ using an impact-parameter-dependent equivalent-photon framework with photonuclear inputs from TALYS calculations and ENDF evaluations. Across the two input sets, the predicted Ru/Zr ratios span $1.54$ - $1.71$ for exact $1 n$ and $2.49$ - $3.09$ for $1 n 1 n$ , while inclusive $X n$ (at least one neutron) and $X n X n$ ratios remain near unity at $0.96$ - $0.99$ and $1.05$ - $1.10$ , respectively. The one-neutron ratios lie well above the corresponding flux-only $Z^{2}$ and $Z^{4}$ charge-scaling references, reflecting differences in the low-energy one-neutron response that are amplified by mutual tagging. This topology hierarchy identifies neutron-tagged isobar ratios as sensitive probes of photonuclear response, revealing response differences hidden in inclusive dissociation. These calculations also provide neutron-emission inputs for neutron-tagged vector-meson photoproduction in isobar collisions.
hep-ph
10
Spectroscopy of $n c n c c ˉ$ , $nnnn c ˉ$ , and $nnn c c ˉ$ pentaquarks within the framework of Regge phenomenology
Vandan Patel · Ajay Kumar Rai
We investigate the mass spectra of the $ncnc\bar{c}$, $nnnn\bar{c}$, and $nnnc\bar{c}$ pentaquark systems, where $n$ denotes a light $u$ or $d$ quark, within a leading-order linear Regge approximation. The extension of the baryon intercept and inverse-slope additivity relations to these systems is implemented as a minimal cluster-additive ansatz for compact color-antitriplet diquarks, rather than assumed to be an exact QCD relation. By analyzing the corresponding trajectories in the $(J,M^2)$ plane, we first determine the allowed mass range of the ground-state $ncnc\bar{c}$ pentaquark and extract the associated Regge parameters. Using these inputs, we estimate the mass intervals of the excited states of the $ncnc\bar{c}$, $nnnn\bar{c}$, and $nnnc\bar{c}$ systems. We also obtain analytical mass-inequality relations. The resulting spectra exhibit a systematic ordering with increasing total spin and orbital excitation along the Regge trajectories. We further compare the predicted states with selected kinematically compatible meson--baryon thresholds as a qualitative guide to possible nearby channels. Our results provide a useful reference for future theoretical studies and may serve as a guide for experimental searches and spin-parity assignments of pentaquark candidates in the open- and hidden-charm sectors.
hep-ph
11
Dijet hadrochemistry: tomography of jet-induced medium excitation and diffusion wake
Cong Yi · Xiang-Yu Wu · Zhong Yang · Pi Duan · Guang-You Qin · Xin-Nian Wang · Wenbin Zhao
Energetic partons traversing the quark-gluon plasma in relativistic heavy-ion collisions induce a medium response that modifies the production of associated hadrons, whose chemical composition provides a sensitive probe of this response. We study jet-associated hadrochemistry using the coupled linear Boltzmann transport and hydrodynamics model with a hybrid hadronization scheme that combines Cooper--Frye particlization, quark coalescence and string fragmentation. For inclusive charged jets in $p + p$ and 0--10\% central Pb+Pb collisions at $s_{NN} = 5.02$ ~TeV, the calculated in-cone $K / π$ and $p / π$ ratios are enhanced in Pb+Pb relative to $p + p$ collisions, consistent with preliminary ALICE measurements, with coalescence between shower and thermal partons providing a substantial contribution. Extending the analysis to dijet events, we predict that both ratios are enhanced around the leading and subleading jets, more strongly around the subleading jet and more pronounced for larger radial size. After mixed-event acceptance correction and sideband background subtraction, the yields of associated pions, kaons and protons all become negative near $∣Δ ϕ ∣ ≃ π /2$ , signaling a depletion caused by the diffusion wake. The $K / π$ and $p / π$ ratios of these deficits remain finite and exceed the $p + p$ values around the jet peaks, indicating that the missing hadrons originate from jet-excited medium. These results establish dijet hadrochemistry as an experimentally accessible tomographic probe of jet-induced medium excitation and the diffusion wake.
hep-phnucl-exnucl-th
12
Non-resonant Flavoured leptogenesis with aligned two-Higgs doublet model and right-handed neutrinos
Km Pranjali · Indrani Chakraborty
We explore the possibility of non-resonant flavoured leptogenesis in the framework of the aligned two-Higgs doublet model augmented with two right-handed neutrinos. Considering the lightest heavy neutrino mass between 10 TeV-100 TeV, we calculate the baryon asymmetry of the universe by solving fully flavoured coupled Boltzmann equations and find that the observed baryon asymmetry can be successfully generated for lightest heavy-neutrino masses in this range without relying on resonant enhancement. We compute the flavour-dependent CP asymmetries and washouts as well. Unlike conventional analyses based on only one Higgs doublet, in this framework, both Yukawa structures associated with the scalar doublets contribute to the CP asymmetry, and their combined effect plays an essential role in realizing the observed lepton asymmetry. We find that the flavoured lepton asymmetry survives if the washout in that direction is weak. The CP asymmetries in the other flavour directions suffer strong washout. The surviving flavour-dependent lepton asymmetry becomes the main contributor to the final baryon asymmetry. We perform a comprehensive numerical analysis to identify the allowed regions of the multi-dimensional parameter space compatible with neutrino oscillation data, perturbativity of the Yukawa couplings, charged-lepton flavour violation and the observed baryon asymmetry.
hep-ph
13
Chiral Symmetries in the Standard Model of Particle Physics and its Extensions
Sergio Ferrando Solera
Chiral gauge theories are a central focus of research in theoretical particle physics due to the parity symmetry breaking observed in the Standard Model. Left-Right Symmetric Models (LRM) explain the breaking of parity through a Spontaneous Symmetry Breaking Mechanism, predicting new $W_{R}$ and $Z_{R}$ gauge bosons. The absence of direct BSM physics detection at the LHC has driven research towards precision observables and Effective Field Theories (EFTs), particularly the SMEFT framework. Precision radiative calculations in chiral theories using dimensional regularization require a $D$ -dimensional $γ_{5}$ prescription, such as the mathematically consistent Breitenlohner-Maison-'t Hooft-Veltman (BMHV) scheme. However, this scheme introduces gauge symmetry-breaking terms that obstruct Slavnov-Taylor identities. A primary objective of this thesis is to provide a pedagogical introduction to cancelling these spurious anomalies via algebraic renormalization, and to derive the one-loop symmetry-restoring finite counterterms required to renormalize the four-fermion operators of the $ν$ SMEFT. Furthermore, the thesis explores UV completions like LRMs embedded in other BSM theories like the Grand Unified Theories. This embedding implies that no discrete symmetries remain at the TeV scale and allows LRMs to be treated as EFTs with the minimal scalar content needed to perform the Spontaneous Symmetry Breaking Mechanism. The second main objective is to derive robust lower bounds on the masses of the new gauge bosons and the LR scale using collider observables. This analysis is performed for both the effective and traditional LRMs, ensuring that the results are independent of other parameters of the theory.
hep-phhep-th
14
Quantum limit to transparency
Angelo Esposito · Alberto Nicolis · Federico Piazza
We argue that no material can be made completely transparent to light as long as it has a nontrivial index of refraction. The quantum decay of photons into phonons is an ineliminable source of attenuation. This survives even once all other excitations have been gapped away, impurities have been removed, and the temperature has been set to zero. Restricting for simplicity to the case of a superfluid, we determine via effective field theory methods the corresponding low-frequency contribution to the imaginary part of the index of refraction. This scales as $ω^{4}$ and induces a nonanalyticity of the real part for $ω \to 0$ . We also extend our result to large coherent electromagnetic fields, such as those of a laser, showing that the effect can receive strong nonlinear enhancements. Our result is a genuine quantum lower bound to the transparency of a medium.
↳ hep-thcond-mat.otherhep-ph
15
The road to $H_{0}$ , $Ω_{m}$ , and $w$ with a global neutrino-telescope network
Pavel Zhelnin · Gonzalo Herrera · Nicholas Kamp · Carlos A. Argüelles
The newly measured correlation between the neutrino and X-ray luminosities of Seyfert galaxies has yielded the first neutrino-based measurement of the Hubble constant. Building on this result, we forecast the reach of a global neutrino-telescope network by 2030, utilizing full-sky IceCube exposures combined with KM3NeT-ARCA and Baikal-GVD. We find that this 2030 configuration sharpens the neutrino-measured Hubble constant from today's $H_{0} = 6 6_{- 37}^{+ 44}$ to $H_{0} = 6 6_{- 13}^{+ 15}$ km s $^{- 1}$ Mpc $^{- 1}$ . Additionally, we project that the disk-corona slope of the neutrino X-ray luminosity relation ( $L_{ν} \propto L_{X}^{β}$ ) will reach $β = 0.72 \pm 0.04$ , enabling a $\geq 5 σ$ exclusion of the calorimetric value $β = 1$ . Finally, we show that, if a high-redshift population of neutrino sources, such as JWST's "little red dots," is identified and obeys the same luminosity relation, we can obtain a new independent measurement of the matter density $Ω_{m}$ and the dark energy equation-of-state parameter $w$ .
↳ astro-ph.COhep-ph
16
Macroscopic study of $ϕ$ -mesic nuclei in $pp$ collisions at $s$ = 7 TeV with the PACIAE model
Qiang Wang · Zhi-Lei She · An-Ke Lei · Dai-Mei Zhou · Wen-Chao Zhang · Hua Zheng · Li-Lin Zhu · Yu-Liang Yan · Zhong-Qi Wang · Ben-Hao Sa
A macroscopic method of the parton and hadron cascade model PACIAE combined with the coalescence model DCPC is employed to study the $ϕ$ -mesic nuclei in $pp$ collisions at $s$ = 7 TeV for the first time in this work. Based on the final hadronic states of $pp$ collisions simulated by the PACIAE model, the $ϕ$ -mesic nuclei: $_{ϕ}^{3} H (ϕ - p n)$ , $_{ϕ}^{4} H (ϕ - p nn)$ , and $_{ϕ}^{4} He (ϕ - pp n)$ are recombined by the DCPC model with constituents of protons, neutrons, and $ϕ$ mesons. Their yields, transverse momentum spectra, and rapidity distributions are simulated separately. These theoretical predictions call for experimental confirmation.
↳ nucl-thhep-ph
17
Distinguishing Flat and Warped Extra Dimensions with Unruh-DeWitt Detectors
Ashmita Das · Anjana Krishnan · Soumitra Sengupta
We examine the response of a two level Unruh-DeWitt (UD) detector interacting with the Kaluza-Klein (KK) mass modes of a bulk scalar field in extra dimensional models. Considering two of the promising extra dimensional models with distinct compactifications, such as large, flat extra dimensions in the Arkani Hamed, Dimopoulos \& Dvali (ADD) framework and warped extra dimensions in the Randall-Sundrum (RS) scenario, we compute the profile function of the detector. We extend this computation to the 6 dimensional doubly compactified spacetime geometry. The profile function of the detector has been examined as a function of the energy gap of the detector, the compactification radius of the extra dimension, and the dimensionality of spacetime, requiring the chosen parameter space appropriately such that the gauge hierarchy problem is duly addressed. We find that the pattern of the profile function is dictated by the spacing of the KK mass spectrum and the resolution of the detector. For ADD model, the spacing between successive KK modes decreases with the increasing compactification radius, yielding a smoothly increasing continuum pattern in the profile function. Whereas for the RS warped geometry model, a tiny deviation in the radius of the extra dimension produces a large change in the same, resulting a sharp increment. The resolvability of the KK mode structure is sensitive to the underlying geometry of the spacetime, providing a qualitative distinction between flat and warped extra dimensional scenarios within the UD detector framework.
↳ hep-thhep-phquant-ph
18
Levy-shaped femtoscopic sources from an exact solution of relativistic hydrodynamics
Bence Szentkuti · Mate Csanad
An important goal of high-energy physics is to better understand the spacetime structure of particle emitting sources created in heavy-ion collisions. For a fraction of a second a special form of matter, the so-called quark-gluon plasma (QGP) is created, which can be examined with the toolkit of femtoscopy. With the measurement of correlation functions it was determined that Lévy distributions describe the shape of QGP sources the most accurately, however, based on hydrodynamics Gaussian distributions are typically expected. In this article we showcase an exact solution of the equations of relativistic hydrodynamics, which aims to resolve this puzzle by providing Lévy distributions directly from hydrodynamics. A detailed analysis reveals whether the predictions of this solution are in accordance with observations.
↳ nucl-thhep-ph
19
Local Diagnostics of Learned Event Representations for Anomaly Detection at the HL-LHC
Donatella Genovese · Philip Ploner · Simone Scardapane · Stefano Giagu · Thea Klaeboe Aarrestad
Anomaly detection, the identification of collision events that deviate from Standard Model expectations, is one of the most promising model-agnostic strategies for new-physics searches at the Large Hadron Collider. Searching for rare events in learned low-dimensional representations removes the need to commit to hand-crafted observables a priori, but sacrifices the immediate physical interpretation those observables provide. For anomaly detection to enter a discovery pipeline, flagged events must therefore be diagnosed locally, both to distinguish potential new physics from mismodeling or detector effects and to identify observables for targeted follow-up searches. We evaluate supervised and self-supervised neural embedding strategies on COLLIDE-2V, a 750-million-event dataset simulated under realistic High-Luminosity LHC conditions, using the reconstruction error of an autoencoder trained in the learned latent space as the anomaly score. Across the configurations and benchmark signals considered, supervised objectives, which exploit simulation process labels during training, generally outperform their self-supervised counterparts and, in their best configurations, improve on an autoencoder trained directly on kinematic features, raising the signal efficiency at 10% background acceptance on all held-out processes. We further introduce a local diagnostic pipeline that fits a Gaussian Mixture Model to the SM latent space, profiles each component through high-level observables without process labels, localizes the flagged events, and ranks observables by their local discriminating power. The ranking recovers the defining kinematics of the held-out processes, while correlating the anomaly score with the same observables quantifies how closely the score tracks them, revealing cases where the most discriminating observable is not the one the score follows most closely.
↳ cs.AIhep-exhep-phphysics.data-an