HEP Phenomenology·hep-ph

Wed·Aug 5, 2026Wednesday·August 5, 2026

35 papers—26 primary·9 cross-listed

01
Overlapping resonance branches of a gauge-invariant Lorentz-violating massive vector
Zurab Kepuladze🇬🇪
We investigate the propagation and resonance behavior of an Abelian massive vector field in the presence of a gauge-invariant, CPT-even, dimension-four Lorentz-violating kinetic operator constructed from a single preferred four-vector. In the massless theory, the propagator contains an additional algebraic pole that decouples from conserved currents, leaving two physical degrees of freedom. After spontaneous breaking of the internal U(1) symmetry, all three vector polarizations become physical but separate into two orthogonal dispersion branches carrying two and one physical polarization states, respectively. We show that this decomposition is preserved under Dyson resummation for a transverse matter vacuum polarization and calculate the corresponding decay rates and fermion-annihilation amplitude. The split-pole structure and associated double resonance behavior cannot be understood through a finite number of perturbative Lorentz-violating insertions. The contribution of the second branch in physical processes is strongly dependent on the initial momentum geometry: it vanishes for massless head-on fermions in a timelike background, whereas boosted nearly parallel configurations can generate an energy-enhanced correction. Spacelike and lightlike backgrounds additionally lead to directional and potentially sidereal variations of the resonance signal.
hep-phhep-th0 citations
02
Rank and Scale Tests of Shell-Motivated Fermion-Mass Ansatze with a Constrained Neutrino Extension
Yaroslav D. Krivenko-Emetov🇦🇹 · Oleksii M. Lytvynenko🇺🇦
We study whether the observed hierarchy of quark and lepton masses can be described by a small set of simple relations between the three fermion generations. Using the nine charged-fermion Yukawa couplings at the common scale M_Z, we distinguish genuine mass relations from those that arise simply because a model has enough freedom to reproduce the data. A systematic scan of projector-based models identifies a particularly accurate relation between the first- and third-generation mass slopes. We then construct more restrictive models that also constrain the second generation and test them by leave-one-out reconstruction. Several six-parameter models predict all nine charged masses with errors of only a few percent; the best fixed models reduce the worst leave-one-out error to about 4% without adding continuous parameters. We also give a possible microscopic interpretation of the most successful integer relations. Two mass-independent combinations of Standard-Model quantum numbers reproduce the required charged-sector pattern, and simple twofold or threefold matching classes fix the relative coefficient before the masses are used. In a separate two-loop running test, a down-sector ratio close to 1/15 near 6 x 10^6 GeV evolves to a value close to 1/14 at M_Z. The same framework gives neutrino-mass sums near 0.059-0.061 eV for normal ordering, while one family also allows inverted ordering near 0.103 eV. These results do not prove preons or fermion compositeness, but provide concrete targets for future microscopic models.
hep-ph0 citations
03
Neutrino Fluxes at a Muon Collider
Francis M. Burk🇺🇸 · Tao Han🇺🇸 · Wolfgang Kilian🇩🇪 · Felix Kling🇩🇪 · Joachim Kopp🇩🇪 · Zahra Tabrizi🇺🇸
While muon colliders are primarily considered precision machines for new physics searches at the energy frontier, they are also intense sources of high-energy neutrinos. Large fluxes of electron and muon neutrinos are produced in the decay of beam muons, especially along the straight sections around the experiments. In this work, we re-evaluate these neutrino fluxes using the latest design of a \SI{10}{TeV} muon collider and find that fluxes around the interaction region are almost two orders of magnitude higher than earlier estimates. We also compute the fluxes of neutrinos produced in $μ^{+} μ^{-}$ collisions, electromagnetic showers induced by electrons from muon decay, and interactions of neutrinos close to the collider ring. We find that these additional neutrino sources are non-negligible and would lead to a sizable number of neutrino interactions of all flavors, including several tau neutrino events, in a ton-scale detector placed in the forward direction. We discuss the physics opportunities offered by muon collider neutrinos in the context of QCD and nuclear physics, electroweak precision measurements, and searches for new physics.
hep-phhep-ex1 citation
04
The Forward Neutrino Flux and its Secondaries at a 10 TeV Muon Collider
Ju-Yeol Choi🇺🇸 · Matheus Hostert🇺🇸 · Peiran Li🇺🇸 · Zhen Liu🇺🇸
Muon decays in a muon collider ring would produce TeV neutrino and antineutrino beams of electron and muon flavor. We study this flux in the forward $μ^{+}$ and $μ^{-}$ beam directions at a 10 TeV muon collider and introduce \mint, a dedicated Monte Carlo simulation to model neutrino fluxes accounting for muon beam dynamics. We find that a benchmark detector at 5 km from the interaction point would see about $O (1 0^{9})$ neutrino interactions per year in a $\sim 3$ ~tonne fiducial volume with a beam spot size of $O (1)$ ~meter. We calculate the number of secondary muons and neutrinos generated by neutrino interactions in the rock upstream of the forward detectors and find that about two secondary high-energy and highly polarized muons from the rock would cross each detector per bunch crossing. Neutrino productions of charmed mesons and taus in the rock generate a small $ν_{τ} + ν ˉ_{τ}$ secondary flux, with $O (0.2)$ events per year in the detectors, likely too small to be observed. Wrong-sign neutrinos from similar processes, such as $ν_{e} + ν ˉ_{μ}$ in the $μ^{-}$ beam, are more numerous but still a fraction no larger than $O (1 0^{- 8})$ of the number of TeV neutrino interactions. Finally, we outline how the large forward neutrino exposure can be used to search for beyond-the-Standard-Model particles produced in neutrino interactions, with examples of heavy neutral leptons coupled to electron and muon flavors through mixing or electromagnetic dipole operators.
hep-phhep-ex0 citations
05
Abundant production of scalars and axions from phase transition bubble expansion
Isabel Garcia Garcia🇺🇸 · Gaurang Ramakant Kane🇬🇧 · John March-Russell🇬🇧 · Andrea Paolini🇺🇸
We revisit aspects of particle production during cosmological first-order phase transitions, and show that the expansion of true-vacuum bubbles can be a copious source of particle production. Specifically, for a massive spin-0 field linearly coupled to the bubble profile, spherical bubbles expanding even at \emph{constant} radial velocity efficiently produce particles until the local-rest-frame radius of curvature of the bubble wall exceeds the particle Compton wavelength -- contrary to the expectation that walls moving at constant speed cannot radiate. We compute the momentum spectrum of the produced particles for both accelerated and constant-velocity expansion histories, identify the regimes of coherent and incoherent production, quantify the validity of the perturbative treatment, and show that this mechanism can parametrically dominate other production processes of feebly coupled particles, including freeze-in. Our results apply to many models of light, feebly coupled particles studied in the literature, providing new sources of dark radiation and dark matter. In particular, a first-order deconfinement-confinement transition in a hidden Yang-Mills sector can abundantly produce axion-like particles, leading to dark radiation and/or dark matter signatures over large regions of parameter space.
hep-phastro-ph.CO0 citations
06
High-Frequency Gravitational Wave Detection with Superconducting Qubits
Heechan Yi🇰🇷 · Seong Chan Park🇰🇷 · Kyoungchul Kong🇺🇸 · Myeonghun Park🇰🇷
High-frequency gravitational waves (HFGWs) provide a unique window into high-energy and early-universe physics, yet they evade traditional macroscopic interferometry. To bridge this detection gap, we propose a novel quantum-sensing paradigm utilizing superconducting transmon qubits embedded in resonant microwave cavities. Through the inverse Gertsenshtein effect, HFGWs propagating in a static magnetic field resonantly excite a cavity mode. By leveraging the characteristic spin-2 quadrupolar pattern of the induced electromagnetic field, we position qubits directly at the electric-field hot spots of the $TE_{212}$ mode to act as localized sensors. Crucially, configuring this array as an entangled quantum register via symmetric Dicke states unlocks a fundamental scaling advantage: the signal probability scales quadratically with the qubit number, translating to a $h_{m i n} \propto n_{q}^{- 3/4}$ strain sensitivity scaling. We demonstrate that an idealized global register of 800 qubits reaches a strain sensitivity that surpasses standard macroscopic cavity-power limits by five orders of magnitude. Benchmarked against representative axion-haloscope parameters, this collective quantum enhancement decisively mitigates the profound Planck-scale suppression inherent to gravitational interactions, establishing a transformative framework for next-generation HFGW searches in the GHz band.
hep-phhep-exquant-ph1 citation
07
Virtues and Vices of Equivariant Transformers
Luigi Favaro🇧🇪 · Tilman Plehn🇩🇪 · Huilin Qu🇨🇳 · Jonas Spinner🇬🇧
We study for the first time the benefit of Lorentz-equivariant transformers for large-size jet tagging and flavor tagging. To control their computing demands, we optimize all implementations for inference cost metrics. In our scaling studies, we find that Lorentz-equivariant networks outperform standard transformers, provided geometric features are relevant. This holds true in an idealized world as well as for limited resources. The conditional gain from Lorentz equivariance provides interesting input to the development of foundation models for LHC data.
hep-phhep-ex1 citation
08
Flavor-violating dark matter at MEG-II and Mu3e
Daniele Barducci🇮🇹 · Giulio Marino🇮🇹 · Paolo Panci🇮🇹 · Robert Ziegler🇩🇪
We investigate the potential of high-intensity muon experiments such as MEG~II and Mu3e to uncover dark matter (DM) through the lepton-flavor-violating decay $μ^{+} \to e^{+} χ χ ˉ$ . We describe the underlying interactions in terms of dimension-six four-fermion operators and systematically explore all allowed Lorentz structures. We show that precision measurements of the Michel spectrum can probe new-physics scales of $O (TeV)$ for DM masses above approximately $1 MeV$ . For lighter DM, whose signal is confined close to the Michel endpoint, the radiative decay $μ^{+} \to e^{+} χ χ ˉ γ$ at MEG~II opens a complementary window, with sensitivity comparable to and, in some regions, stronger than that of the non-radiative channel. Remarkably, for reheating temperatures below the tens-of-MeV scale but above the BBN bound, MEG~II and Mu3e can probe regions in which freeze-in through the very same LFV interactions accounts for the observed DM abundance.
hep-phhep-ex0 citations
09
Fermionic Dark Matter in a Scotogenic Model with a Complex Scalar Singlet
Gustavo Ardila-Tafurth🇨🇱 · Andrés Flórez🇨🇴 · Victor Martín-Lozano🇪🇸 · Avelino Vicente🇪🇸
We study the phenomenology of the complex scoto-singlet model, an extension of the scotogenic framework that simultaneously accounts for radiative neutrino masses and fermionic dark matter. We perform a Markov Chain Monte Carlo scan of the parameter space, imposing theoretical consistency together with constraints from neutrino oscillation data, lepton-flavor violation, collider searches and the observed dark matter relic abundance. Viable dark matter solutions are found both near the Higgs resonance and in coannihilation regions, extending the allowed mass range with respect to the minimal scotogenic model. Direct- and indirect-detection signals are strongly suppressed, placing most of the viable parameter space beyond the reach of current experiments. At colliders, monojet searches offer the best prospects to probe our model in compressed-spectrum scenarios, while long-lived charged scalars may give rise to displaced or detector-stable signatures.
hep-ph0 citations
10
Critical coupling with zero-mode corrections in discretized light-cone quantized $ϕ^{4}$ theory
Shreeram Jawadekar🇺🇸 · Mamoon A. Sharaf🇺🇸 · James P. Vary🇺🇸
We present an advancement for solving the Discretized Light-Cone Quantization (DLCQ) Hamiltonian for mass spectra in 2D $ϕ^{4}$ theory that incorporates perturbative zero-mode contributions. We demonstrate that this correction accelerates numerical convergence of the mass eigenstates with increasing resolution and yields a critical coupling of comparable accuracy with a substantial reduction in computational costs. Specifically, with more than one order of magnitude reduction in basis space dimensionality we achieve an extrapolated critical coupling of $23.10 \pm 0.25$ compared with $23.53 \pm 0.26$ in the larger basis but without zero-mode correction. We employ Gaussian Process Regression for extrapolation to the continuum limit. The approach we present here is prospective for studies of higher-dimensional gauge theories.
hep-phhep-thnucl-th0 citations
11
Neutrino flavor-wave transport: Numerical tests and theoretical challenges
Anson Kost🇺🇸 · Lucas Johns🇺🇸 · Huaiyu Duan🇺🇸
Neutrino quantum kinetics is computationally intractable in the neutrino-dense arenas of core-collapse supernovae and neutron star mergers. Flavor-wave (or flavomon) transport is an emerging approach to this problem in which small-scale flavor inhomogeneities are treated as quasiparticles with properties determined by the local mean background. We present the first numerical calculations of flavor-wave transport under slow driving. Our results show some quantitative successes but also underscore the theoretical challenges that need to be overcome. Two issues are particularly concerning. (1) Nonlinear wave-wave coupling may be important. (2) Degeneracies and small energy gaps are responsible for significant nonadiabatic transitions. Future work will need to address these points if flavor-wave transport is to be viable in settings of astrophysical interest. Other topics examined include flavor-wave parallel transport and flavor-space symmetry breaking.
hep-phastro-ph.HE0 citations
12
Minimal Scale-Invariant Dark Matter
Alexander Belyaev🇬🇧 · Roman Pasechnik🇸🇪 · Rishav Roshan🇬🇧 · Alfonso Zerwekh🇨🇱
We study the minimal classically scale-invariant extension of the Standard Model, containing a single $Z_{2}$ -stabilised real scalar singlet whose mass is not an independent input but is generated dynamically through the quantum effective potential and linked to radiative electroweak symmetry breaking through the Higgs portal. We construct the full two-field one-loop effective potential and introduce a modified on-shell renormalisation scheme that fixes the electroweak vacuum, the Higgs mass, the vanishing Higgs--singlet mixing and the singlet curvature at the physical point, yielding predictions stable under renormalisation-scale variation. Since thermal freeze-out is excluded by direct-detection limits, we identify a highly predictive freeze-in realisation of this model. Imposing perturbativity, vacuum stability and the observed relic abundance leads to a freeze-in solution with a dark-matter mass of around $2 MeV$ . The predicted electron-scattering cross section for this solution lies far below the current sensitivity of DAMIC-M. Current direct-detection experiments therefore do not constrain this scenario. The minimal scale-invariant singlet model thus provides a robust and highly predictive framework connecting radiative electroweak symmetry breaking and freeze-in dark-matter genesis.
hep-phastro-ph.COhep-th0 citations
13
Possible Bound States in the $D^{*} D ˉ^{*}$ / $B^{*} B ˉ^{*}$ and $D^{*} D^{*}$ / $B ˉ^{*} B ˉ^{*}$ Systems within the Bethe-Salpeter Formalism
Ce Li🇨🇳 · Jing-Juan Qi🇨🇳 · Zhu-Feng Zhang🇨🇳 · Zhen-Yang Wang🇨🇳 · Xin-Heng Guo🇨🇳
We investigate possible $S$ -wave bound states in the $D^{*} D ˉ^{*}$ , $B^{*} B ˉ^{*}$ , $D^{*} D^{*}$ , and $B ˉ^{*} B ˉ^{*}$ systems within the Bethe-Salpeter formalism using one-boson-exchange interactions. Bound state solutions are obtained in the isoscalar hidden-heavy systems with $J^{P C} = 0^{++}$ , $1^{+-}$ , and $2^{++}$ , whereas no isovector solutions are found within the parameter range considered. For the doubly heavy systems, solutions are obtained in the allowed $I (J^{P}) = 0 (1^{+})$ , $1 (0^{+})$ , and $1 (2^{+})$ systems, although the $1 (0^{+})$ solution requires a comparatively large cutoff parameter. The bottom systems are bounded more favorably than their charmed counterparts because of their larger reduced masses.
hep-ph0 citations
14
Spin correlation of hyperon-antihyperon systems in $e^{+} e^{-}$ annihilation
Wenyu Zhang🇨🇳 · Yang Li🇨🇳 · Xiaorong Zhou🇨🇳 · Qun Wang🇨🇳
Quantum correlations in high-energy collisions provide a novel perspective on both fundamental physics and hadron structure. We calculate the quantum information observable in spin-1/2 particle-antiparticle systems produced in $e^{+} e^{-}$ annihilation. Starting from the two-qubit density operator, we calculate the Bell variable, concurrence and negativity as functions of the scattering angle and collision energy for the $Λ Λ ˉ$ , $Σ^{+} Σ ˉ^{-}$ , and $Λ_{c}^{+} Λ ˉ_{c}^{-}$ systems in the process $e^{+} e^{-} \to B B ˉ$ at BESIII experiments. Unlike elementary particle-antiparticle systems, the hyperon-antihyperon system exhibits non-vanishing transverse polarization for $B$ and $B ˉ$ with respect to the production plane, which significantly restrict the kinematic region where the CHSH inequality is violated while leaving the entanglement largely unaffected. We also extend our analysis to the general case of spin-1/2 particle-antiparticle production, and explore the potential of using quantum correlations as probes to hadron structure, particularly to the parton-level entanglement inside heavy-flavored mesons.
hep-ph1 citation
15
Faddeev equations for the $J / ψ N N$ and $ϕ N N$ three-body systems in momentum space
Xu Zhang🇨🇳
We construct Faddeev equations for the $J / ψ N N$ and $ϕ N N$ three-body systems in momentum space. The two-body subsystem $t$ -matrix is obtained by solving the Lippmann-Schwinger equations. The $N N$ interactions are constructed using the Malfliet-Tjon potential. The $J / ψ N$ interaction potentials in the $^{4} S_{3/2}$ and $^{2} S_{1/2}$ channels are taken from HAL QCD. The $ϕ N$ interaction potential in the $^{4} S_{3/2}$ channel is also taken from HAL QCD. The $^{2} S_{1/2}$ $ϕN$ interaction is obtained from the combination of the $ϕp$ correlation function analysis and the HAL QCD results, as well as from the assumption that the spin-spin parts of the $ϕN$ and $J / ψ N$ interactions are inversely proportional to the respective hadron masses. The Faddeev equations are solved to find bound states in the $J / ψ N N$ and $ϕ N N$ three-body systems. The numerical results suggest that there exist bound states in the $ϕ N N$ three-body system, while there is no bound state in the $J / ψ N N$ system.
hep-phnucl-th0 citations
16
Unraveling weak radiative hyperon decays with broken flavor symmetry
Kaiwen Chen🇨🇳 · Lin Qiu🇨🇳 · Jin Sun🇰🇷 · Zhi-Peng Xing🇨🇳 · Ruilin Zhu🇨🇳
We present a broken $S U (3)$ flavor analysis of weak radiative decays of spin-1/2 hyperons, incorporating current-current and electromagnetic-penguin contributions as well as charge- and mass-insertion effects. Six independent reduced amplitudes describe all decay channels, while a minimal relation between the parity-conserving and parity-violating form factors reduces to eight free parameters. A global fit to the ten available observables yields $χ^{2} / d.o.f. = 0.98$ and accommodates the large negative asymmetry in $Σ^{+} \to p γ$ . The resulting nonzero effective form factor $g_{b_{8}}$ provides a possible flavor-symmetry realization of the parity-violating amplitude while remaining compatible with Hara's theorem, which constrains the current-current contribution in the exact symmetry limit. Our analysis favors a sizable negative value of $α_{γ} (Ξ^{-} \to Σ^{-} γ)$ , which differs from the current experimental result by approximately $1.3 σ$ . Future precision measurements of this observable will provide a decisive test of this prediction.
hep-ph0 citations
17
Analysis of the $X (2370)$ as a glueball based on rigorous current-field duality
Zhi-Gang Wang🇨🇳
In this work, we take the $X (2370)$ with $J^{P C} = 0^{-+}$ as a glueball consists of three valence gluons, and construct a six-quark current based on rigorous current-field duality to obtain the glueball-quark Lagrangian. Then we perform Fierz transformation to bosonize the quark current into a series of three pseudoscalar mesons. At last, we obtain ratios among the partial decay widths of the glueball to three pseudoscalar mesons in a model-independent way, which are compatible with the experimental data from the BESIII Collaboration and support assigning the $X (2370)$ as a glueball.
hep-ph2 citations
18
On the nature of fully-charmed four-quark exotic state $X (6900)$ from its photoproduction off nuclei
E. Ya. Paryev🇷🇺
The possibility to study the nature of fully-charmed tetraquark state $X (6900)$ from its inclusive photoproduction off nuclei near the kinematic threshold is investigated within the collision model based on the nuclear spectral function. The model accounts for $X (6900)$ production in direct photon--nucleon interactions as well as three different scenarios for its internal structure: compact tetraquark, molecule of the two hidden-charm $J / ψ$ and $ψ (3770)$ mesons and the mixture of both of them. We calculate within these scenarios the absolute and relative excitation functions on $^{12}$ C and $^{184}$ W nuclei at near-threshold photon energies of 30--40 GeV, the absolute momentum differential cross sections and ratios of them for the $X (6900)$ meson production off these target nuclei at laboratory polar angles of 0 $^{\circ}$ --5 $^{\circ}$ and for photon energy of 35 GeV as well as the A-dependences of its transparency ratios at photon energy of 35 GeV. We show that these observables reveal a definite sensitivity to the $X (6900)$ intrinsic structure. Therefore, they might be useful for the determination of this structure from the comparison of them with the experimental data from the future experiments at the upcoming experimental facilities, such as the planned electron-ion colliders in the United States and China.
hep-phhep-exnucl-exnucl-th1 citation
19
Probing Heavy-Quark Spin Symmetry in Double $J / ψ$ Hadroproduction
Zhi-Guo He🇨🇳 · Xiao-Bo Jin🇨🇳 · Bernd A. Kniehl🇩🇪
We perform the first complete $O (α_{s}^{5})$ analysis of the prompt hadroproduction of $J / ψ$ pairs with large transverse momenta $p_{T}^{ψ ψ}$ in the nonrelativistic-QCD factorization framework, including all possible Fock state combinations $c c ˉ (m) + c c ˉ (n)$ , with $m, n =^{3} S_{1}^{[1, 8]},^{1} S_{0}^{[8]},^{3} P_{J}^{[1, 8]}$ . We observe that CMS and ATLAS data constrain a specific linear combination of the long-distance matrix elements (LDMEs) $⟨ O^{J / ψ} (^{1} S_{0}^{[8]})⟩$ and $⟨ O^{J / ψ} (^{3} P_{0}^{[8]})⟩$ . In conjunction with two other combinations fixed by single prompt $J / ψ$ hadroproduction, we gain a new LDME set, which turns out to be largely compatible with the world data of prompt $J / ψ$ yield and polarization and to probe heavy-quark spin symmetry, by which agreement is established with LHCb data of prompt $η_{c}$ yield. Our $O (α_{s}^{5})$ predictions also nicely agree with CMS and ATLAS data in the lowest bins of $J / ψ$ pair invariant mass $m^{ψ ψ}$ , beyond leading-order kinematics.
hep-phhep-ex0 citations
20
Hierarchical Axiverse
Hai-Jun Li🇨🇳
String compactifications generically produce $O (100)$ light axion-like particles, yet low-energy mixing has not previously been exploited as a structuring constraint on their spectrum. We show that the requirement of well-defined QCD-induced mass mixing forces the axion masses into a hierarchically spaced ordering, while stochastic mixing organizes the decay constants into a hierarchically split distribution -- two populations separated by an essentially empty window. Both patterns are insensitive to ultraviolet input and satisfy the relevant Swampland constraints within standard large-volume compactifications. We term this emergent pattern the hierarchical axiverse.
hep-phhep-th0 citations
21
Two-loop QCD amplitudes for $t t ˉ W$ production at the LHC in the leading-colour approximation
Matteo Becchetti🇮🇹 · Dhimiter Canko🇮🇹 · Xiang Chen🇨🇭 · Vsevolod Chestnov🇮🇹 · Maximilian Delto🇨🇭 · Sara Ditsch🇩🇪 · Tiziano Peraro🇮🇹 · Mattia Pozzoli🇮🇹 · Chiara Savoini🇩🇪 · Simone Zoia🇨🇭
We present a numerical computation of the two-loop QCD scattering amplitudes for the production of a top-antitop quark pair in association with a $W$ boson ( $t t ˉ W$ ) at the LHC in the generalised leading-colour approximation, retaining the exact dependence on the top-quark and $W$ -boson masses. Rather than pursuing a fully analytic calculation, we employ a hybrid framework that combines numerical evaluation with strong algebraic and analytic control, allowing ultraviolet and infrared singularities as well as large intermediate cancellations to be treated exactly. This is achieved by expressing the finite remainder in terms of a set of special functions with rational coefficients. The special functions are evaluated numerically by solving differential equations through power-series expansions, while the values of the rational coefficients are reconstructed, point by point, from finite-field evaluations. The calculation is performed in the 't Hooft-Veltman scheme and validated against an independent implementation in conventional dimensional regularisation employing a substantially different computational strategy. We finally provide the colour- and polarisation-summed hard functions evaluated on the phase-space grid used in a previous computation of the next-to-next-to-leading-order QCD corrections to the $t t ˉ W$ cross section.
hep-phhep-th0 citations
22
Formation of Quark-Gluon Plasma droplets under Ultra-Relativistic Heavy Ion Collisions in the presence of magnetic fields with a modified hadronic medium
Ananya Sharma🇮🇳 · Divya Rathee🇮🇳 · Agam K. Jha🇮🇳
We build upon the previous studies conducted in this domain using the density of states of various components of the quark-gluon plasma(QGP) modelled after the Thomas-Fermi and Bethe models. This study provides an analysis of the stability of the quark-gluon plasma droplet by the inclusion and variation of chemical potential and magnetic field. An effective mass term is included to account for both the rest mass and thermodynamic mass terms of the quarks and gluon. We also expand on the inclusion of a different meson, kaon, into the medium of the droplet. The analysis on these quantities is done by calculating the free energy of the system and examining it as a function of droplet radius, chemical potential and magnetic field to find conditions for stable droplet formation. We discover that a kaonic medium, along with a pre-existing pionic medium, provides greater stability to the system. At the same time, it is realised that the parameters of chemical potential and magnetic field, due to their opposing effect, help in containing the droplet. Further calculations on entropy and heat capacity yield information about the nature of the phase transition of the system. Our analysis and results are in accordance with lattice QCD simulations.
hep-ph0 citations
23
Deser formula for the shift of energy levels of hadronic atoms in terms of the effective radius of the strong interaction with the Coulomb wave function of hadronic atoms at the origin
O. Voskresenskaya🇷🇺
It is shown that the relations between probabilities of A_2{\pi}-atoms creation in ns-states, derived with neglecting of strong interaction between pions, remain practically unchanged if the strong interaction is taken into account in the first order of perturbation theory. The formulation of Deser equation for the energy shift of energy levels of hadronic atoms is given in terms of the effective range of strong interaction and the relative correction to the Coulomb wave function of hadronic atoms at the origin, caused by the strong interaction.
hep-ph0 citations
24
Di-Higgs Production and Trilinear Higgs Self-Coupling in the scNMSSM: Qualitative Implications for the Electroweak Phase Transition at large {\lambda} and Low tan\b{eta}
Marwa Telba
The trilinear Higgs self-coupling and di-Higgs production cross section are investigated in the semi-constrained NMSSM (scNMSSM) at large- $λ$ / low- $tan β$ with full two-loop precision. A random scan of one million parameter points subject to theoretical, collider, flavor, and dark matter constraints yields 66 SM-like points with singlet fraction $S_{13}^{2} < 0.05$ , all found in the mass range $m_{h_{1}} \in [122.0, 125.0] GeV$ --- a feature that reflects an intrinsic property of the scNMSSM at large- $λ$ / low- $tan β$ , where doublet-dominated configurations are kinematically confined below $\sim 125 GeV$ . The trilinear coupling ratio is found to be universally suppressed: $κ_{λ} = 0.884$ -- $0.982$ , $⟨ κ_{λ} ⟩ = 0.944 \pm 0.018$ . The non-resonant di-Higgs cross section at $s = 13.6 TeV$ lies in the range $30.3$ -- $36.9 fb$ ( $0.88$ -- $1.05 σ_{SM}$ ), with the resonant contribution via $g g \to h_{3} \to h_{1} h_{1}$ negligible ( $\leq 0.004 fb$ ). All predictions are consistent with current ATLAS+CMS di-Higgs upper limits and is expected to be probed at the HL-LHC. These results are discussed in the context of the electroweak phase transition, where the universal suppression of $κ_{λ}$ is qualitatively consistent with a modified Higgs potential that could support a strengthened first-order transition. A quantitative determination of the phase transition strength via finite-temperature analysis is left for future work.
hep-phMod. Phys. Lett. A (2026) 2650207·1 citation
25
Mono-X Signal Characterization from Two-component Dark Matter Using a Convolutional Neural Network
Max Fusté Costa🇸🇪 · Yong Sheng Koay🇸🇪 · Stefano Moretti🇬🇧
We assess the scope of a Convolutional Neural Network (CNN) in characterizing potential signals of two-component Dark Matter (DM) arising at the Large Hadron Collider (LHC) from mono-jet and mono-Z probes. We show that such a CNN has the ability of not only inferring the presence of two DM particles but also of extracting their mass and spin, the latter being either 0 or 1/2, following detector level analysis. However, such result represents a conceptual proof-of-concept, as we have not entertained a signal-to-background analysis.
hep-ph0 citations
26
Revised exclusion limits on doubly charged Higgs bosons from a reanalysis of the ATLAS multi-lepton search at $s = 13$ ,TeV
Kirtiman Ghosh🇮🇳 · Arun Kumar Nayak🇮🇳 · Debabrata Sahoo🇮🇳
The ATLAS search for pair-produced doubly charged Higgs bosons in multi-lepton final states using the full Run 2 dataset [Eur. Phys. J. C 83 (2023) 605] reports the strongest limits to date on the mass of doubly charged scalars, driven by an essentially background-free four-lepton channel. We show that the four-lepton signal efficiency implied by the auxiliary cutflow of that analysis exceeds a strict, mass-independent upper bound derived from the equal-branching-ratio assumption of the search, the leptonic $τ$ branching fractions, and the ATLAS lepton reconstruction efficiencies. We show that this excess cannot be explained by hadronic $τ$ or jet misidentification without invoking fake rates far above realistic values. We regenerate the signal independently and recompute the exclusion limit, using the corrected signal yields, the ATLAS background predictions and uncertainties, and the same $C L_{s}$ procedure implemented in pyhf. The resulting expected limit lies systematically above the ATLAS expected limit, by roughly a factor of two or more. This shifts the expected lower mass bound from $1065$ GeV to $\sim 950$ GeV in the left-right symmetric type-II seesaw model, and from $880$ GeV to $\sim 770$ GeV in the Zee--Babu model.
hep-phhep-ex1 citation
27
Enthalpy-Based Thermal Response and Its Exact Relation to the Speed of Sound in Finite-Temperature QCD
S. D. Campos🇧🇷
A precise characterization of the QCD phase transition remains a fundamental open problem, primarily due to the intrinsically non-perturbative nature of the dynamics that govern the breakdown of We quantify the logarithmic thermal variation of the normalized enthalpy density in finite-temperature Quantum Chromodynamics using a dimensionless response thermal function, $H (T)$ . We establish an exact identity that links $H (T)$ to the speed of sound, $c_{s}^{2} (T)$ . Using continuum-extrapolated lattice Quantum Chromodynamics, Monte Carlo uncertainty propagation, and cubic spline interpolation, we extract a stable peak at $T_{peak} \approx 153.6 MeV$ ( $H_{peak} \approx 6.24$ ), which remains robust under changes in the smoothing parameter $s$ . By contrast, $H (T) = 0$ for the MIT Bag Model despite its non-vanishing trace anomaly. We highlight $H (T)$ as an effective diagnostic of the QCD crossover and discuss its limitations for universal critical scaling at zero chemical potential.
↳ hep-lathep-phhep-th0 citations
28
Partial Waves for Multipositivity
Jaehoon Jeong🇰🇷
We develop a partial-wave formalism providing the missing spin-resolved framework for multipositivity among massless planar amplitudes. We present a systematic procedure for constructing kinematic charts realizing the complex-forward limit. Applying it to obtain the four-, five-, and six-point charts, we show how to derive the one-to-two and one-to-three wavefunctions and construct the associated partial waves. The resulting formalism places higher-point multipositivity on the same footing as conventional partial-wave analyses of two-to-two scattering.
↳ hep-thhep-ph1 citation
29
Determination of the Angular Momentum of Radiated Gravitons, Scalars, and Dark Photons from Binary Orbits
Arpan Hait🇮🇳 · Subhendra Mohanty🇮🇳
We compute the energy and angular momentum radiated by compact binaries through gravitational waves, scalar and vector fields, using the field-theoretic approach. We observe that each emitted graviton carries away an angular momentum of $J ˙ / N ˙ ≃ 2ℏ$ , not only for elliptical orbits (as has already been pointed out by Page [arXiv:2409.00305]) but also for hyperbolic orbits. We extend the analysis to scalar and vector radiation and find that the angular momentum carried by each emitted quantum of radiation is approximately $ℏ$ , i.e., $J ˙ / N ˙ ≃ ℏ$ for both types of radiation. We demonstrate that the radiated energy and angular momentum of binary systems can be determined from the evolution of the orbital angular frequency and the eccentricity of the quasi-Kepler orbit. However, a gauge-invariant decomposition of the angular momentum carried by the emitted particles into the spin and orbital components is not possible.
↳ gr-qcastro-ph.COhep-phhep-th0 citations
30
The Utility of Sparse Error Detection in Quantum Simulations
Henry Froland🇺🇸 · Dorota M. Grabowska🇺🇸 · Sebastian Grieninger🇺🇸 · Jeremy Hartse🇺🇸 · Anne L. Lashbrook · Zhiyao Li🇺🇸 · Ziyuan Li · Sarah J. M. Powell · Martin J. Savage🇺🇸 · Xiaojun Yao🇺🇸 · Nikita A. Zemlevskiy🇺🇸
The recent success of error detecting codes points toward their potential application to fault-tolerant simulations of nature. In this work, we examine the utility of sparse error detection for simulating lattice gauge theories using quantum computers. In particular, we study the time evolution of the lattice Schwinger model embedded into the Iceberg code family, $[[N + 2, N, 2]]$ , as well as the Hypercube code family, $[[2^{N}, N, 2]]$ . The lattice of electrons and positrons in the axial gauge is embedded into a single code block or into multiple code blocks, and this work finds that large codeblocks are advantageous in the absence of connectivity constraints. Noisy classical simulations with realistic near-term error rates, infrequent syndrome measurements and physics-aware postselection are found to improve observable estimation. Under realistic noise rates for near-term quantum computers, this work finds that sparse error detection in quantum simulations has the potential to improve accuracy of observable estimation. Additional rounds of error detection are found to systematically drive errors in observables to the noise floor set by the code. These findings suggest that incorporating minimal implementations of fault tolerance in the near-term will enhance the performance of quantum simulations in nuclear physics and high-energy physics.
↳ quant-phhep-lathep-phnucl-th2 citations
31
Kick Velocities and Mass Function of Free-Floating Planets from Dynamical Ejection in Hierarchical Three-Body Systems
Hugh Kramer🇺🇸 · Stefano Profumo🇺🇸
Free-floating planets (FFPs), also known as rogue planets, are sub-stellar objects that travel through the Galaxy unbound to any host star. Their velocity distribution carries information about the dynamical channel that released them from their birth systems, while their mass distribution encodes the underlying abundance of planets available for ejection. We present a suite of direct $N$ -body simulations of hierarchical three-body systems consisting of a Solar-mass host star, a massive giant perturber, and a lighter planet treated in the restricted three-body regime. We vary the mass of the ejected planet, the mass of the giant perturber, the light planet's semi-major axis, and the eccentricities of both planets, measuring the asymptotic ejection velocity $v_{\infty}$ and the finite-radius ejection speed $v_{kick}$ at the first accepted ejection output. The ejected body's mass has little effect on the outcome over four orders of magnitude, confirming the test-particle limit. By contrast, the giant-planet mass sets the ejection scale and time, following the secular scaling $t_{ejec} \propto M_{J}^{- 1}$ . The eccentricities mainly affect the high-velocity tail rather than the median: a higher light-planet eccentricity extends the kick ceiling to $\sim 23$ km/s, while a highly eccentric giant can yield rare kicks near $80$ km/s via pericentre-enhanced slingshot encounters. We interpret these trends with a semi-analytic framework based on Hill-scale scattering, the Tisserand parameter, and an eccentricity-dependent upper envelope for slingshot energy exchange, and discuss how the ejection velocities map onto the Galactic FFP velocity dispersion and how the mass function sets the microlensing timescale distribution relevant for Roman and Euclid.
↳ astro-ph.EPastro-ph.GAhep-ph0 citations
32
General-relativistic structure of two-component quantum dark fermion stars
Ilídio Lopes🇵🇹
We develop a general-relativistic framework for two-component quantum dark fermion stars: equilibrium configurations of two degenerate fermion species governed by gravity, a Yukawa-mediated dark fifth force and a globally relevant Bohm quantum-pressure correction. The treatment retains the full covariant form of the nonlinear Klein--Gordon equation in the Schwarzschild interior, with closure relations valid at arbitrary compactness, from the ultralight baseline up to densities of order $0.16 fm^{- 3}$ at which relativistic scalar densities and self-consistent effective fermion masses become unavoidable. Two Lagrangian parameters, the dark-fermion mass and the dimensionless ratio between the Yukawa channel and gravity, together fix the equilibrium structure; a joint measurement of mass and radius therefore constrains the dark-sector microphysics directly from gravitational-wave observables. For particle masses in the band $1 0^{- 11}$ -- $1 0^{- 10}$ eV, the configurations exhibit radii of $3$ - $24 km$ and compactness in the range $0.14$ - $0.34$ , behaving as dual mimickers: at moderate compactness they overlap with neutron stars in mass, radius, and inspiral frequency; at the most compact end ( $κ \sim 0.34$ , $R_{T} / R_{S} ≃ 1.5$ ) they cross the photon sphere and could masquerade as low-mass black holes in the mass-gap region. Tidal-deformability measurements discriminate against both populations: the dimensionless tidal deformability is measurably smaller than the neutron-star value yet remains non-zero, unlike that of a genuine black hole. These objects populate the sensitivity bands of LISA, the Einstein Telescope, and Cosmic Explorer, producing astrometric microlensing signatures individually resolvable by \textit{Gaia}. The framework thus provides a reproducible and falsifiable template for constraining dark-sector properties through multi-messenger observations.
↳ astro-ph.HEastro-ph.GAgr-qchep-ph+1PRD(2026)·0 citations
33
Intersection matrices associated to geometric-ordered bases of Feynman integrals
Iris Bree🇩🇪 · Federico Gasparotto🇩🇪 · Sebastian Pögel🇨🇭 · Xing Wang🇨🇳 · Stefan Weinzierl🇩🇪 · Xiaofeng Xu🇨🇳
In integration-by-parts reduction of Feynman integrals, the order relation in the Laporta algorithm determines a set of master integrals. In this paper we investigate the intersection matrices of the integrands of the master integrals that are obtained from a geometric order relation. With an appropriate definition of integrands and their duals, we find that the intersection matrices are simpler than expected: For a filtration-compatible basis, the entries of the intersection matrix are Laurent polynomials in the dimensional regularisation parameter $ε$ . For an $ε$ -factorised basis, the entries are instead integers, up to an overall power of $ε$ , if the boundary values for the auxiliary functions of the rotation are chosen appropriately. This has practical consequences: We can systematically eliminate certain auxiliary transcendental functions, introduced in going from a filtration-compatible basis to an $ε$ -factorised basis. We provide an algorithm that performs this elimination while minimising the number of required calculations.
↳ hep-thhep-phmath-phmath.MP0 citations
34
Logarithmic Soft Photon Theorem and Waveform Tails in Higher Dimensions
Biswajit Sahoo🇮🇳
We derive the leading logarithmic soft-photon theorem in $d > 4$ spacetime dimensions and its classical radiative counterpart. A direct one-loop analysis in massive scalar quantum electrodynamics (QED) yields a factorizing soft term of order $ω^{d - 4} ln ω$ , although the charged-particle S-matrix is infrared finite. The logarithm is generated by the scale-invariant loop-momentum region $ω ≪ ∣ ℓ ∣ ≪ Λ$ , where $Λ$ denotes a characteristic hard-particle energy scale. At leading radiative order, the corresponding logarithmic contribution to the classical electromagnetic waveform arises from the long-range acceleration of the asymptotic charged particles. In even $d \geq 6$ , the straight-line waveform at this radiative order is distributionally supported in retarded time within an interval whose width is set by the characteristic size of the hard-scattering region, whereas the logarithmic acceleration term produces universal early- and late-time radiative tails proportional to $∣ u ∣^{- (3 d - 10) /2}$ . In odd $d \geq 5$ , straight-line motion already gives a late-time tail at the same radiative order proportional to $u^{- (d - 4) /2}$ . The acceleration correction adds universal late- and early-time terms proportional, respectively, to $ln u / u^{(3 d - 10) /2}$ and $∣ u ∣^{- (3 d - 10) /2}$ . A comparison of Feynman and retarded boundary conditions separates the classically radiative contribution from the intrinsically quantum part of the logarithmic soft factor.
↳ hep-thgr-qchep-ph0 citations
35
Local Spin Polarization in Anisotropic Gubser Flow: Suppression Mechanism and Formulation Dependence
Kenji Fukushima🇯🇵 · Shi Pu🇨🇳 · Dong-Lin Wang🇨🇳
We analytically study the longitudinal spin polarization in relativistic heavy-ion collisions using a perturbed Gubser flow solution. In the large-system-size limit, we derive analytical expression of the local spin polarization along the beam direction. In our treatment, the contributions from thermal vorticity and thermal shear are of comparable magnitudes. The thermal vorticity yields the polarization with a sign opposite to that observed experimentally, while the thermal shear counteracts this effect, helping recover the desired sign. We find that the choice of the reference unit vector aligned with the fluid velocity gives the experimentally observed sign only at low transverse momenta, whereas another formulation with the unit vector fixed along the laboratory time direction yields the desired sign for a wide range of transverse momenta. Notably, a recent formulation with the unit vector normal to the freeze-out hypersurface exhibits an exact cancellation between contributions from thermal vorticity and thermal shear at leading order in the large-system-size limit. We identify a general cancellation pattern with acceleration dominance, which is manifest particularly in the latter two formulations. Thus, the total polarization originates from non-acceleration effects, which need not be substantial even when the elliptic flow is finite, as clearly demonstrated in our analytical results. For comparison, we also discuss the spin polarization in the Hubble flow with rotation.
↳ nucl-thhep-ph0 citations

Affiliations

first authorsco-authorsvia INSPIRE