HEP Phenomenology·hep-ph

Tue·Aug 11, 2026Tuesday·August 11, 2026

44 papers—33 primary·11 cross-listed

01
Ultraviolet Flavor Transmission to T-Violating Neutrino Oscillation Observables in a Seesaw Framework with Sterile Mixing and Planck-Suppressed Corrections
Poulastya Kar🇮🇳 · Bipin Singh Koranga🇮🇳 · Vivek Nautiyal🇮🇳
We construct, numerically validate, and phenomenologically constrain a pipeline connecting a spontaneously CP-violating ultraviolet Type-I seesaw boundary condition to Planck-suppressed corrections of the T-violating oscillation asymmetry and the CP asymmetry in a minimal 3+1 sterile-neutrino framework. The ultraviolet Yukawa structure is reconstructed via Casas-Ibarra parameterization, matched onto the Weinberg operator at seesaw thresholds, and evolved to the electroweak scale using one-loop RGEs. The renormalized operator is combined with a 3+1 sterile sector to build the oscillation Hamiltonian, with Planck-suppressed terms treated perturbatively to yield closed-form first-order corrections. We report three substantive implementation errors identified and corrected during independent module validation. Running transports ultraviolet flavor structure with high fidelity distorting mixing angles and phases at or below the per-mille level despite an overall flavor-blind operator normalization run of about fifty percent. Subjecting the ultraviolet texture to a four-channel phenomenological suite (muon to electron gamma, tau to muon gamma, tau to electron gamma, non-unitarity, and perturbativity) confines the correction to the range between three in one hundred million and three in ten million at the natural scale. We prove the asymmetry correction is exactly independent of Casas-Ibarra angles at all allowed points, affecting the correction only indirectly via allowed heavy spectra. Sterile sector effects are strongly texture-dependent, ranging from suppression to a forty-fold enhancement. Evaluating the corresponding antineutrino Hamiltonian for the CP asymmetry, we find the Planck-induced correction lies two to three orders of magnitude below DUNE's published CP-phase sensitivity floor. We present this as a checked, reproducible negative phenomenological result.
hep-ph1 citation
02
Probing Dark Matter and Phantom Field Effects on Neutrino Oscillations around Black Holes
Ikrom Ergashov🇺🇿 · Bakhtiyor Narzilloev🇺🇿 · Ibrar Hussain🇵🇰 · Bobomurat Ahmedov🇺🇿
This study investigates how dark matter in the background of the phantom field (DMPF) near a black hole influences neutrino flavor oscillations using a two-flavor model. It is found that gravitational effects are cancelled for radially moving neutrinos, causing the oscillation phase to increase with distance and mass-splitting, similar to flat spacetime. However, deflected neutrinos experience additional phase shifts due to dark matter, which slightly alters the mass-difference term and the total phase. Numerical analysis supports these findings and reveals a degeneracy between lens mass and dark matter parameters, affecting the transition probability curves based on source angle changes. Neutrinos modeled as Gaussian wave packets show that decoherence in a gravitational field is minimally influenced by dark matter, with the absolute neutrino mass determining the oscillation duration. Our findings imply that curved spacetime and dark matter significantly impact neutrino oscillations, offering potential insights into dark matter through neutrino astronomy in extreme environments.
hep-phgr-qcEPJC(2026)·0 citations
03
A $Γ_{3}$ modular symmetric approach for two-zero textures in left-right symmetric model
Ankita Kakoti🇮🇳 · Happy Borgohain🇮🇳
The observed pattern for neutrino masses and mixing provides compelling evidence for Beyond Standard Model physics which further motivates the search for predictive frameworks that can simultaneously address flavor structure and its phenomenological consequences. This work particularly investigates the realization of all possible seven two-zero neutrino mass textures within the generic left-right symmetric model with $A_{4}$ modular symmetry. By considering modular weights 4,8 and 10, we systematically construct all the possible classes of 2-0 textures without the introduction of any flavon fields which enhances the predictive power of the framework. In this work, we also identify the texture classes capable of simultaneously accommodating current neutrino data, reproducing the observed baryon asymmetry and also yielding experimentally testable results for the effective Majorana neutrino mass for new physics contributions of neutrinoless double beta decay.
hep-ph0 citations
04
Testing Antimatter Couplings with Spectroscopy
Joerg Jaeckel🇩🇪 · Lucas Puetter🇩🇪
We investigate how scalar-mediated potentials with Lorentz-violating couplings to Standard Model fermions affect spectroscopic observables in atoms and highly charged ions. Suitable combinations of an ordinary scalar and a time-like component of a Lorentz violating vector coupling allow for a split into "matter" and "antimatter" couplings, at least in the non-relativistic limit. By considering hydrogen and antihydrogen spectra, we access both matter and antimatter couplings. While relativistic effects alone lift degeneracies in ordinary hydrogen, providing indirect access to antimatter couplings, comparisons with antihydrogen measurements lead to significantly improved sensitivity to the antimatter couplings. In highly charged ions, enhanced relativistic effects further amplify the sensitivity, compensating for reduced experimental precision and larger theoretical uncertainties. We obtain the strongest bounds to date for scalar masses $m_{ϕ} ≳ 400 keV$ . For comparison, we estimate astrophysical constraints on the same parameter space, providing strong bounds even on antimatter couplings, despite stars being predominantly composed of matter.
hep-phphysics.atom-ph1 citation
05
Neutrinoless Double-Beta Decays from Operator Mixing
J. de Vries🇳🇱 · S. Fajfer🇸🇮 · L. P. S. Leal🇧🇷 · O. Sumensari🇫🇷 · R. Zukanovich Funchal🇧🇷
We perform a complete one-loop Renormalization Group (RG) analysis of neutrinoless double-beta decays within the Standard Model Effective Field Theory (SMEFT). Although several effective operators do not contribute to these processes at tree level, we show that they can generate sizable contributions through operator mixing. By accounting for the full one-loop RG evolution within the SMEFT, we find that the resulting constraints provide the most stringent bounds on numerous dimension-seven operators, improving upon limits derived from meson decays. We also highlight the importance of contributions beyond the first leading logarithm, which can provide the leading effects for specific operators and flavor combinations.
hep-ph0 citations
06
Quest for an Understanding of Pion and Kaon Structure
Zhen-Ni Xu🇪🇸 · Daniele Binosi🇮🇹 · Craig D. Roberts🇨🇳 · José Rodríguez-Quintero🇪🇸
The emergence of massless (Nambu-Goldstone) bosons in association with a dynamically global broken symmetry is a long known and widespread phenomenon in physics. However, practically nothing is known about the expressions of Nambu--Goldstone boson character on the internal structure of these bound states. Indeed, their structure is often ignored. In strong interactions, pions and kaons are the (would-be) Nambu-Goldstone bosons and experiments underway or planned at existing or anticipated high-energy, high-luminosity facilities will gather data that it is hoped will enable maps to be drawn of their internal structure. Meanwhile, theory and phenomenology find themselves in something of a quagmire. Herein, we provide a snapshot of the current status, highlighting issues under debate and identifying areas that deserve greater attention so that best use can be made of what is likely to be a huge volume of data delivered in the next decade or so.
hep-phhep-exhep-latnucl-ex+11 citation
07
Strong decays of the possible $D^{*} K$ and $D ˉ^{*} K$ molecules
Zi-Li Yue🇨🇳 · Dian-Yong Chen🇨🇳 · Elena Santopinto🇮🇹
Inspired by the rich spectrum of structures near the $D^{(*)} K^{(*)} / D ˉ^{(*)} K^{(*)}$ thresholds, we postulate the existence of $S$ -wave $D^{*} K$ and $D ˉ^{*} K$ molecules, denoted as $T_{c s ˉ 1}^{f} (2460)$ with $I = 0$ (corresponding to $D_{s 1} (2460)$ ), $T_{c s ˉ 1}^{a} (2470)$ with $I = 1$ , $T_{c ˉ s ˉ 1}^{f} (2460)$ with $I = 0$ , and $T_{c ˉ s ˉ 1}^{a} (2470)$ with $I = 1$ , respectively. Using an effective Lagrangian approach, we investigate the strong decays of these molecular states. Our estimates indicate that the width of $T_{c s ˉ 1}^{a} (2470)$ is roughly three orders of magnitude larger than that of $T_{c s ˉ 1}^{f} (2460)$ , while the widths of $T_{c ˉ s ˉ 1}^{a / f} (2470)$ are of the same orders as that of $T_{c s ˉ 1}^{f} (2460)$ . The present study may provide valuable clues for the experimental search for these molecular candidates.
hep-ph0 citations
08
Flavor--Kinetic Entanglement Production from Decay and Scattering at Finite Density
Zekun Li🇨🇳 · Jia Liu🇨🇳 · Xiao-Ping Wang🇨🇳 · Jing-Jun Zhang🇨🇳
We extend the scattering-entanglement dictionary to finite-density environments by investigating the flavor--kinetic bipartition of the Hilbert space. We show that tracing over kinematic degrees of freedom maps the total branch-changing transition probability directly onto the leading flavor--kinetic linear entanglement entropy. At finite density, the vacuum branch-changing probability is replaced by an occupation-weighted collision probability, built from the same directed reaction-density kernel that enters the integrated Boltzmann equation. The resulting observable is the bath-averaged flavor--kinetic entanglement entropy of a pair sampled from the medium. As a proof of principle, this framework is applied to an $O (N)$ singlet-scalar extended model to probe thermal phase transitions. In the examples studied, the resulting entanglement entropy serves as a collision-based phase-transition-type diagnostic, exhibiting a finite discontinuity across a first-order phase transition and a nonanalytic temperature derivative for continuous transitions. These examples suggest a novel way to characterize thermal phase structures, distinct from traditional thermodynamic order parameters.
hep-phquant-ph0 citations
09
Hadronic photon correction to $γ^{*} γ \to f_{2} (1270)$ at next-to-leading order
Bing-Xin Liu🇨🇳 · Shen-Qiang Ren🇨🇳
Within the framework of light-cone sum rules, we calculate the hadronic photon corrections to the $γ^{*} γ \to f_{2} (1270)$ transition form factors induced by the leading-twist photon distribution amplitude of the real photon. We establish the factorization formula for the vacuum-to-photon correlation function at next-to-leading order in $α_{s}$ , and extract the perturbative hard matching coefficients by applying the method of regions. The parametrically large logarithms appearing in the hard functions are resummed to next-to-leading logarithmic accuracy by solving the two-loop evolution equation for the corresponding light-ray tensor operator. Combining the resulting light-cone sum rules with the known leading-power contributions from QCD collinear factorization, we provide updated theoretical predictions for the three helicity form factors $T_{0} (Q^{2})$ , $T_{1} (Q^{2})$ and $T_{2} (Q^{2})$ , including an estimate of the theoretical uncertainties.
hep-ph0 citations
10
Neutrino Mass and its Impact on Gravitational Waves from Domain Wall Collision
Victoria Puyam🇮🇳 · Mrinal Kumar Das🇮🇳
The $A_{4} \times Z_{4}$ symmetry models are constructed to study neutrino masses and mixings, as well as the gravitational-wave spectrum from domain-wall annihilation. The first neutrino mass model is constructed with the flavon's vacuum expectation value and alignment obtained from the self-interacting potential terms, while the second model uses a new vacuum expectation value arising from a potential containing both self-interaction and mixed terms. The resulting neutrino mixing patterns for both models are in good agreement with current neutrino oscillation data with different mixing values. Further, the flavon mixing terms lift the vacua degeneracy that often shows in the spontaneous symmetry breaking of the discrete symmetry. These mixing terms and the modified neutrino mass matrix of the second model are considered to produce the necessary bias for analysing the gravitational waves spectrum. The spectrum predicted by the model could be detected by current and near-future experiments when the flavons have the vacuum expectation value of $1 0^{4}$ TeV.
hep-ph0 citations
11
Probing Memory-Burdened Primordial Black Holes with High-Energy Neutrinos
Arian Moradi Asl · Sandhya Choubey🇸🇪 · Andreas Lund🇸🇪
The memory-burden effect can suppress the late-time evaporation of primordial black holes (PBHs), allowing those that would otherwise have evaporated via Hawking radiation to survive until the present epoch. These lighter PBHs emit high-energy and ultra-high-energy neutrinos, opening the tentalizing possibility of discovery via neutrino telescopes. We study the constraints on memory-burdened PBHs from current IceCube HESE, MESE, and EHE data; and forecast the sensitivity reach of IceCube-Gen2 radio and GRAND200k. In particular, we study how this signal depends on whether the initial PBH population is described by a log-normal mass function or by a monochromatic one. We find that log-normally distributed populations can be more strongly constrained than monochromatic populations with the same median mass primarily because their low-mass tails enhance the high-energy neutrino flux. We show that current IceCube data provide the leading limits for a lower memory burden parameter $k$ , whereas the projected radio detectors become substantially more sensitive for higher values of $k$ . We also study a scenario where future experiments would see a positive signal coming from PBHs. We consider a representative 30-event signal in IceCube-Gen2 radio and GRAND200k and study how well one could distinguish the two mass-function hypotheses. We find that it is easier to disfavor the monochromatic distribution when the log-normal distribution is assumed to be true. Finally, we study how well the parameters of the memory-burdened PBHs can be estimated in these future experiments.
hep-phastro-ph.HE1 citation
12
Open Path Geometric Phases in Three Flavor Neutrino Oscillations through Layered Matter
N. Razzaghi🇮🇷
We present a gauge invariant formulation of open path geometric phases in the context of three flavor neutrino oscillations traversing nonuniform matter. In contrast to the standard Berry phase, which is intrinsically associated with closed adiabatic cycles, neutrino propagation from source to detector typically traces an open trajectory within the parameter space of matter dependent Hamiltonians. We derive this formalism within a layered matter framework, where each discrete layer is characterized by a constant density and a local matter eigenbasis. The total evolution operator is expressed as a path ordered product of dynamical propagation factors and interface matrices that bridge adjacent matter eigenbases. This construction naturally yields geometric phase chains composed of endpoint projections and interface overlaps. We demonstrate that these chains remain invariant under arbitrary local rephasings of the instantaneous matter eigenstates, thereby resolving the gauge dependence ambiguity typically associated with open path transport. The proposed formalism elucidates the noncommutative nature of flavor evolution in layered media, illustrating that profiles with identical column densities but distinct ordering can yield different transition amplitudes. Furthermore, we analyze the influence of the Dirac CP phase, showing that it deforms the geometry of matter eigenbasis transport without being equivalent to the geometric phase itself. In the continuous limit, finite interface overlaps converge to Berry connection factors, while endpoint projections remain indispensable for ensuring open path gauge invariance. We discuss the phenomenological implications of this structure, emphasizing that geometric phases are not independent observables but contribute to transition probabilities via interference among coherent propagation chains.
hep-ph0 citations
13
Correlated low-energy constants in large- $N_{c}$ chiral perturbation theory
Pere Masjuan🇪🇸
The combined chiral and large- $N_{c}$ expansion is increasingly employed in precision studies involving the $η$ and $η^{'}$ mesons, including recent applications to low-energy axion phenomenology within U(3) chiral perturbation theory. We point out that the operator structure of the large- $N_{c}$ chiral Lagrangian naturally induces correlated directions among the low-energy constants $(F_{0}, L_{4}, C_{16})$ and $(F_{0}, L_{6}, C_{20})$ , implying that phenomenological analyses determine correlated combinations of couplings rather than independent low-energy constants. Using the determination of the pion decay constant as an illustrative example, we reinterpret existing phenomenological and lattice determinations in terms of these correlated directions, showing that the well-known anticorrelation between $F_{0}$ and $L_{4}$ extends naturally to NNLO through $C_{16}$ . These correlated directions lead to a practical prescription for interpreting and propagating phenomenological determinations of the low-energy constants consistently within the combined chiral and large- $N_{c}$ framework.
hep-phhep-lat0 citations
14
Topological analysis of scale-invariant spatial fluctuations in ultrarelativistic heavy-ion collisions
Salman Khurshid Malik🇮🇳 · Ramni Gupta🇮🇳 · Fakhar Ul Haider🇮🇳 · Balwan Singh🇮🇳
The QGP-to-hadronic matter phase transition and QCD critical point in heavy-ion collisions can be identified by studying spatial fluctuations among final-state particles using intermittency analysis. First CMC-based intermittency analysis in the two-dimensional angular ( $η$ , $φ$ ) phase space, using EPOS as the background model is presented. Critical fluctuation signals are extremely weak, constituting only a few percent of the total event sample and are severely diluted by the overwhelming non-critical background, rendering traditional intermittency analyses insufficient for reliable signal extraction. To extract the weak critical signal, we employ a two-stage topological machine learning framework combining Topological Data Analysis (TDA) with deep learning. In the first stage, particle events are represented as two-dimensional point clouds and a Delaunay-based sub-level set filtration is constructed to extract Betti curves as multiscale topological invariants, corrected for multiplicity bias via azimuthal randomisation and classified by two complementary architectures, a TopoPointNet (TPN) and Boosted Decision Trees (BDT). Since event-level classification alone is insufficient to restore the critical scaling, a second stage applies a particle-level density filter, explicitly stripping away the diffuse thermal background and isolating the densely packed critical clusters. The two stage pipeline successfully restores the power-law scaling of the normalized factorial moments, enabling accurate recovery of the intermittency index in ( $η$ , $φ$ ) space and establishing topological machine learning as a robust data driven tool for probing the QCD critical point and the phase structure of strongly interacting matter in heavy-ion collisions at LHC energies.
hep-phhep-ex0 citations
15
Perturbative Dissipation in Minimal Warm Inflation
Daniel J. H. Chung🇺🇸 · Nidhi Sudhir🇺🇸 · Lian-Tao Wang🇺🇸
We present an analysis of the perturbative modes of dissipation in the minimal warm inflation model where an axion-inflaton is coupled to a gluon thermal bath through the axion-gauge coupling. The corresponding friction coefficient, which generically is governed by IR physics, for the processes we consider is dominated by Landau damping of soft space-like gluons and the plasmon decay of hard on shell gluons. Since both of these processes are IR dominated, the friction coefficient becomes sensitive to the non-perturbative magnetic mass scale $m_{g}^{- 1} \sim (α T)^{- 1}$ which in turn leads to the friction coefficient's overall linear proportionality to $α$ , which is much less suppressed in $α$ powers compared to the well understood term from Chern-Simons (CS) diffusion $(\propto α^{5})$ . On the other hand, this contribution to the friction coefficient is suppressed due to slow roll. We show that this can be viewed as a suppression of local spontaneous CPT violation for derivative couplings in general and that time correlations of nonlocal variables which do not fall off at large time separations are what allow an unsuppressed friction coefficient.
hep-phgr-qchep-th0 citations
16
QCD Sum Rule Analysis of Triply Heavy $(Q Q ˉ) (Q q ˉ)$ Tetraquark States with $J^{P} = 0^{\pm}$
Wen-Shuai Zhang🇨🇳 · Chun-Gui Duan🇨🇳 · Zhi-Hui Guo🇨🇳 · Liang Tang🇨🇳
Within the framework of QCD sum rules, we systematically investigate the mass spectra and possible decay patterns of the $(c c ˉ) (c q ˉ)$ and $(b b ˉ) (b q ˉ)$ tetraquark states with quantum numbers $J^{P} = 0^{\pm}$ . Based on two distinct color configurations, $[8_{c}]_{Q Q ˉ} \otimes [8_{c}]_{Q q ˉ}$ and $[1_{c}]_{Q Q ˉ} \otimes [1_{c}]_{Q q ˉ}$ , we construct 18 interpolating currents for these states, and obtain stable sum rules for a subset of them. By calculating the corresponding two-point correlation functions, we extract their mass spectra. For the $(c c ˉ) (c q ˉ)$ system, we identify four possible tetraquark states: two with $J^{P} = 0^{+}$ , namely $T_{3 c, 0} (4760)$ and $T_{3 c, 0} (5000)$ , and two with $J^{P} = 0^{-}$ , denoted as $T_{3 c, 0} (5040)$ and $T_{3 c, 0} (5370)$ . For the $(b b ˉ) (b q ˉ)$ system, the extracted masses are found to lie in the ranges $13.72$ -- $14.02$ GeV for the $J^{P} = 0^{+}$ states and $13.90$ -- $14.22$ GeV for the $J^{P} = 0^{-}$ states. We further analyze their possible decay modes. Our results indicate that $T_{3 c, 0} (5000)$ , $T_{3 c, 0} (5040)$ , and $T_{3 c, 0} (5370)$ can decay into a charmonium state and a charmed meson, and are therefore expected to have appreciable decay widths. By contrast, $T_{3 c, 0} (4760)$ and all predicted $(b b ˉ) (b q ˉ)$ tetraquark states are expected to be relatively narrow, since the corresponding two-body strong decays via the fall-apart mechanism are kinematically forbidden. Therefore, $T_{3 c, 0} (4760)$ and all predicted $(b b ˉ) (b q ˉ)$ tetraquark states are promising candidates for experimental searches in final states containing a $D$ or a $B ˉ$ meson, accompanied by light hadrons or a photon.
hep-phhep-ex0 citations
17
The $π /12$ model: trimaximal first-column lepton mixing with charged-lepton $μ$ -- $τ$ breaking
Vernon Barger🇺🇸
The first column of the lepton mixing matrix carries two independent magnitude conditions: the trimaximal norm $∣ U_{e 1} ∣^{2} = 2/3$ and the $μ$ -- $τ$ balance $∣ U_{μ 1} ∣ = ∣ U_{τ 1} ∣$ . We parameterize their violation by $ε_{1} \equiv (3/2) ∣ U_{e 1} ∣^{2} - 1$ and $ε_{2} \equiv 3 (∣ U_{τ 1} ∣^{2} - ∣ U_{μ 1} ∣^{2})$ and show that current data treat the two differently in central value: including the first JUNO measurement, $ε_{1} = + 0.014 \pm 0.010$ is consistent with zero, while $ε_{2} = + 0.2 9_{- 0.13}^{+ 0.07}$ is large but disfavors zero at only $1.5 σ$ on the global-fit profile likelihood, the driving phase being still poorly measured. This asymmetry selects the $π /12$ model. Its neutrino sector is TM $_{1}$ with the electron-row condition $∣ U_{e 2} ∣/∣ U_{e 3} ∣ = 2 + 3$ that fixes $sin^{2} θ_{13} = (2 - 3) /12 = 0.02233$ and $sin^{2} θ_{12} = 0.31811$ . A charged-lepton 2--3 rotation $R_{23} (θ_{e}, α)$ leaves the electron row exactly invariant and generates $ε_{2} = sin 2 θ_{e} cos α$ . In an $S_{4} \times C_{4} \times C_{3} \times C_{2}$ realization, the rotation arises from a single additional flavon whose alignment forces $α = 0$ ; a natural angle $θ_{e} ≃ 2^{\circ}$ then reproduces the departure of $θ_{23}$ from maximal while pinning the CP phase to $δ = 27 2^{\circ} \pm 2^{\circ}$ , near-maximal CP violation with $ε_{2} = - 0.066$ . The current $θ_{23}$ -- $δ$ measurements thereby become a sharp test: the predicted $δ$ sits $1.7 σ$ from the present central value on the same profile likelihood, the predicted $ε_{2}$ has the opposite sign to the measured one, and the Hyper-Kamiokande design precision of $2 0^{\circ}$ on $δ$ resolves the question at $3 σ$ . The mass predictions are inherited unchanged, $Σ m_{ν} = 65.6$ meV and $m_{β β} = 5.4$ meV, at the current DESI bound in $Λ$ CDM.
hep-ph0 citations
18
Spectroscopic and Structural Properties of $B$ , $B_{s}$ , and $B_{c}$ Mesons within a Non-Relativistic Potential Model: A Comparative Analysis via Matrix Numerov and Variational Methods
Pritom Kumar Nath · Rishan Dev Choudhury · Jugal Lahkar
In this work, we studied the spectroscopic masses, decay constants, oscillation frequencies, and Isgur-Wise function parameters of $B$ , $B_{s}$ , and $B_{c}$ mesons within the framework of a non-relativistic potential model. The interaction is modelled using the Killingbeck potential, with calculations performed using two complementary approaches: the matrix Numerov method for solving the Schrödinger equation and the quantum mechanical variational method employing the Gaussian wave function. We determined the unknown parameters of the Killingbeck potential by fitting it to the Cornell potential using the ordinary least squares (OLS) method. These calibrated parameters are then used to compute the aforementioned physical observables.We obtained the masses of the heavy mesons with deviations of less than 0.5\% from the highly precise experimental data. We also discussed the drawbacks and limitations of the non-relativistic model and highlighted its domain of applicability. At the end, we compare our results obtained from both methods with those from other theoretical frameworks, including QCD sum rules, lattice QCD, and alternative potential model studies.
hep-ph0 citations
19
Small-instanton effects in an atlas of KSVZ axion models
Ning Chen🇨🇳 · Saurabh K. Shukla🇮🇳
We investigate small-instanton contributions to the axion potential across a range of KSVZ models containing vector-like quarks~(VQs), using naive dimensional analysis. We consider scenarios containing a single VQ, multiple identical copies, and sets of distinct VQs, requiring in each case that the gauge couplings remain perturbative up to the Planck scale under the two-loop gauge running. The associated fermion zero-mode content varies between these cases, requiring different combinations of mass insertions and scalar--Yukawa contractions for its saturation. Increasing the copies of VQs can render the instanton-size integral dominated by instantons of the smallest size, corresponding to the scale near the ultraviolet~(UV) cut-off. The resulting contribution then becomes sensitive to the UV completion and the induced potential can compete with, or dominate over, the ordinary QCD contribution. Assuming that the QCD and small-instanton potentials are aligned, we determine the resulting axion-mass shift and its consequences for the axion--photon coupling. When the small-instanton induced susceptibility becomes comparable to or larger than the QCD susceptibility, the physical axion mass of $m_{a}$ is enhanced at fixed decay constant~ $f_{a}$ , while the axion-photon of $g_{aγ γ}$ coupling remains controlled by $f_{a}$ and the anomaly ratio of $E / N$ . The standard QCD relation among $m_{a}$ , $f_{a}$ and $g_{aγ γ}$ is consequently modified, opening new regions of the $(m_{a}, g_{aγ γ})$ plane for axion searches.
hep-phhep-th0 citations
20
Phenomenology of different cross-section models at DUNE
Subrajit Puhan🇮🇳 · Monojit Ghosh🇭🇷 · Rukmani Mohanta🇮🇳 · Amit Pal🇮🇳 · S.K. Swain🇮🇳
In this paper, we study the impact of different cross-section models in the measurement of the neutrino oscillation parameters in DUNE. In particular, for the quasi-elastic (QEL) region, we considered the Llewellyn-Smith formalism (LS) and the Hartree-Fock Continuum Random Phase Approximation (HF-CRPA) and for the resonance (RES) region, we consider the Rein-Sehgal (RS) and the Berger-Sehgal (BS) models, and compare our results with the DUNE cross-section tune (Valencia model for QEL and RS model for RES), which was considered in their technical design report. Our results show that while the DUNE tune is best for QEL, the best model for RES is BS. As the DUNE energy region is mainly dominated by RES, for the total cross-section, the HF-CRPA+BS model provides the best strength in the cross-section, whereas the DUNE tune is the weakest among all the configurations considered in our work. Regarding the neutrino mass ordering, CP violation and octant sensitivity, the HF-CRPA+BS model provides $(25 - 30)$ % improvement, and regarding the precision of the $θ_{23}$ and $Δ m_{32}^{2}$ , the same model provides $(15 - 20)$ % improvement as compared to the DUNE tune.
hep-ph0 citations
21
The role of thermal photons in a magnetized plasma and their significance in heavy ion collisions
Zhaolu Ouyang🇨🇳 · Xinyang Wang🇨🇳
In this contribution, we present thermal photon production mechanisms within a magnetized quark-gluon plasma, utilizing the framework of Landau-level quantization. We examine the specific influences of the magnetic field, chemical potential, and chiral chemical potential on photon yield and polarization. By providing a more comprehensive theoretical description of photon production across the full evolution of heavy-ion collisions, our study offers a promising new avenue for resolving the photon $v_{2}$ puzzle and potentially detecting the signature of magnetic fields in heavy-ion collision experiments.
hep-phActa Phys.Polon.Supp.(2026)·1 citation
22
Sneutrino Tribrid Inflation in Flipped $SU (5)$ : Confronting ACT DR6 and Planck
Farishta Israr🇵🇰 · Mansoor Ur Rehman🇸🇦 · Saleh O. Allehabi🇸🇦
We construct a realization of sneutrino tribrid inflation within the $R$ -symmetric flipped $S U (5)$ grand unified theory. A vector-like pair of matter multiplets, $1 0_{V} + 10_{V}$ , provides a $D$ -flat inflaton direction along the right-handed sneutrino component, with an additional $Z_{2}$ symmetry forbidding a direct inflaton mass term so that the leading inflationary interaction is a non-renormalizable Kähler-driven operator. Unlike previous studies, we treat the superpotential cutoff scale $M_{s}$ as independent of the reduced Planck mass, $m_{P}$ , substantially enlarging the viable parameter space. Confronting the model with the ACT DR6/Planck determination $n_{s} = 0.9734 \pm 0.0034$ and the $2 σ$ bound on the running of the spectral index, we identify broad regions of viable parameter space in which the flipped $S U (5)$ symmetry-breaking scale can approach the conventional GUT scale, $M ≃ M_{GUT}$ , and the tensor-to-scalar ratio can reach observable values, $r ≳ 1 0^{- 3}$ , within reach of forthcoming CMB $B$ -mode experiments such as LiteBIRD and CMB-S4. We further study the post-inflationary dynamics, identifying the inflaton with the lightest right-handed sneutrino in a conventional type-I seesaw sector, whose out-of-equilibrium decay generates a lepton asymmetry that is converted into the observed baryon asymmetry via non-thermal leptogenesis and electroweak sphalerons, for a reheating temperature consistent with both successful leptogenesis and the gravitino constraint.
hep-ph0 citations
23
Comment on "Regarding the Rotational Unruh Effect"
S. R. Mane🇺🇸
We comment on various statements in a recent document (A.~Deur, S.~J.~Brodsky, C.~D.~Roberts and B.~Terzić, Regarding the Rotational Unruh Effect, \textit{arXiv:2607.25004v1 [hep.ph]}, (2026)). The examples cited treat electrons (or positrons) circulating and emitting photons in high-energy storage rings. The topic is also of interest in astrophysics, for electrons orbiting in magnetic fields around neutron stars.
hep-phphysics.acc-ph0 citations
24
Near-threshold resonances in $e^{+} e^{-}$ annihilation
S.G. Salnikov🇷🇺 · A.E. Bondar🇷🇺 · A.I. Milstein🇷🇺
Near-threshold resonances have been discovered in many hadron pair production processes, resulting in a significant increase in reaction cross sections at low relative velocities of the produced particles. The natural cause of such resonances is the interaction between slow hadrons in the final state. Our review demonstrates that, in virtually all known cases, final-state interactions successfully explain the results of numerous experiments demonstrating a nontrivial energy dependence of cross sections for processes near reaction thresholds. A comprehensive study of near-threshold resonances in various processes can provide new information about the interaction between hadrons at large distances.
hep-phhep-ex0 citations
25
The Challenge of Detecting Quantum Nature of Gravitational Waves
Yu Miyauchi🇯🇵 · Hidetoshi Omiya🇯🇵 · Atsuhisa Ota🇨🇳 · Hiroki Takeda🇯🇵 · Takahiro Tanaka🇯🇵
We investigate whether squeezing can provide an observable signature of quantum gravitational waves. Because a realistic detector couples only to a particular wave-packet mode, squeezing in global source modes need not remain observable. We show that inflationary two-mode squeezing reduces to an unsqueezed thermal state in the accessible one-mode sector, phase incoherence washes out squeezing in stochastic backgrounds, and the limited coverage of the solid angle of detectors strongly suppresses squeezing from isolated sources. We then show that source squeezing is not essential, {\it i.e.}, a quantized gravitational wave can generate a positive squeezing witness if the detector state is initially prepared in a squeezed state, whereas a classical external gravitational field cannot, producing only a displacement. However, the resulting signal is bounded by the extremely small graviton--detector coupling. Thus, detector squeezing can remove the need for squeezed incident waves, but not the suppression caused by weak gravitational interaction.
hep-phgr-qc1 citation
26
Improved Regge Kinematics and All-Path-Length Corrections to Momentum Broadening in the Quark-Gluon Plasma
Dario van den Berg🇿🇦 · Isobel Kolbe🇿🇦
We present a study of transverse momentum broadening for high-energy partons propagating through the quark-gluon plasma (QGP), extending the Gyulassy-Levai-Vitev (GLV) formalism to include both all-path-length (APL) corrections and improved sub-Regge kinematics. The standard GLV framework relies on the large separation distance and large formation time approximations, which are well justified in large nuclei but may become unreliable in small collision systems, where the relevant length and coherence scales are comparable. Working to first order in the opacity expansion, we derive analytic expressions for the transverse momentum broadening distribution and the corresponding momentum transport coefficient, $q^$ , while systematically relaxing these approximations. The APL correction arises from relaxing the large separation distance approximation, whereas the sub-Regge and combined sub-Regge-APL corrections are obtained using an improved set of Regge kinematics beyond the strict Regge limit. We find that these corrections can substantially modify both the transverse momentum broadening distribution and the momentum transport coefficient, particularly for short path lengths and high exchanged momentum, providing a more complete theoretical description of momentum broadening in the QGP.
hep-phnucl-th0 citations
27
Quark spin-orbit correlations in spin-1 targets
Hyunwoo Kim🇰🇷 · June-Young Kim🇰🇷
The quark spin-orbit correlation probes the alignment of quark helicity with longitudinal kinetic orbital angular momentum inside a hadron. This correlation is defined by a QCD operator: the position moment of the asymmetric parity-odd quark energy-momentum tensor. The matrix element of this rank-two tensor decomposes into symmetric-traceless, antisymmetric, and trace parts. The symmetric-traceless part is matched to moments of axial generalized parton distributions. The QCD equations of motion relate the antisymmetric part to vector and tensor form factors and set the trace to zero. Using these relations, we derive two gauge-invariant sum rules for the spin-orbit correlation in a spin- $1$ hadron. One gives the correlation in an unpolarized target. The other gives its tensor-polarization dependence, which is absent for spin- $0$ and spin- $1/2$ targets. We estimate the unpolarized spin-orbit correlations for the $ρ$ meson and deuteron using existing lattice and phenomenological inputs, respectively.
hep-phhep-lat0 citations
28
Transverse distributions of the energy-momentum tensor for a spin- $3/2$ baryon
Hui-Jae Lee🇰🇷 · Ki-Hoon Hong🇰🇷 · June-Young Kim🇰🇷 · Hyun-Chul Kim🇰🇷
We develop a multipole description of transverse distributions of the energy-momentum tensor for a spin- $3/2$ baryon in frames connected by a longitudinal boost. In the transverse Breit frame, the $T^{00}$ , $T^{03}$ , and $T^{33}$ matrix elements are expressed through seven multipole form factors for energy, angular momentum, and stress. At finite longitudinal momentum, we factorize the Lorentz mixing of these three components from the spin- $3/2$ Wigner rotations of the external states. The resulting elastic-frame matrix elements contain six transverse multipoles, whose Fourier transforms define the distributions of energy, longitudinal momentum, and longitudinal momentum flux. We also calculate $T^{++}$ , $T^{+-}$ , and $T^{--}$ directly with light-front Rarita-Schwinger spinors. The elastic-frame construction provides a continuous interpolation from the transverse Breit frame to the infinite-momentum frame. In this limit, the Wigner rotation becomes the Melosh rotation, and the leading elastic-frame matrix elements reproduce the corresponding light-front results. Using the $Δ$ -baryon gravitational form factors obtained in the Skyrme model as a representative numerical input, we find that the energy distribution is dominated by the energy monopole defined in the transverse Breit frame and changes only weakly under longitudinal boosts. Through boost mixing, this monopole provides the dominant contribution to the longitudinal momentum distribution and its flux at finite $P_{z}$ . For a longitudinally polarized spin- $3/2$ target, the distributions contain only the monopole contributions, whereas those of a transversely polarized target exhibit spin-dependent quadrupole and octupole deformations and a dipole that shifts their maxima.
hep-ph0 citations
29
Effects of Born-Infeld Electrodynamics on Chiral Symmetry Restoration and Meson Susceptibilities in Holographic QCD
Hiwa A. Ahmed🇷🇴 · Peshwaz A. Abdoul🇮🇶
Within a holographic QCD framework, we numerically investigate chiral symmetry breaking and the associated phase transition at finite temperature and chemical potential. The model is constructed on a nonlinear charged Born-Infeld black hole background. The chiral condensate, extracted from the asymptotic behavior of the bulk scalar field, serves as the primary order parameter. At zero chemical potential, we find a chiral crossover transition for physical quark masses with a pseudocritical temperature of $T_{p c} = 0.1477$ GeV. In the chiral limit, the transition becomes first-order with a critical temperature of $T_{c} = 0.1337$ GeV. A critical strange quark mass of $m_{s} = 37$ MeV, at zero light quark mass, separates first- and second-order transition regions. For finite chemical potential ( $μ$ ) and a physical strange mass ( $m_{s} = 95$ MeV) with massless light quarks, the transition remains second-order, with $T_{c}$ decreasing as $μ$ increases. These results are further supported by the behavior of meson susceptibilities $(χ_{π} - χ_{σ})$ , which exhibit a rapid thermal decay and convergence across the phase boundary. Introducing the Born-Infeld parameter $β$ shifts the second-order phase boundary to higher temperatures for smaller $β$ (stabilizing the chirally broken phase) but does not alter the transition order or introduce a critical endpoint within the studied range. Our findings are consistent with previous soft-wall model studies and highlight the significant role of nonlinear bulk electrodynamics in modifying the chiral phase diagram.
hep-phhep-lathep-th0 citations
30
The Living Guide of Machine Learning for Particle Physics
Claudius Krause🇦🇹 · Ramon Winterhalder🇮🇹 · Matthew Feickert🇺🇸 · Benjamin Nachman🇺🇸
We started the Living Review of Machine Learning for Particle Physics (HEP-ML Living Review) in 2020 as a community-maintained, near-comprehensive bibliography of machine learning in particle physics. The field was then growing faster than any single researcher could follow, finding the relevant papers was hard, and a structured, continuously updated reference paid off immediately. Since then the literature has grown by more than an order of magnitude, the methods reach far beyond the classification and generation tasks of the early years, and the community has built its own ecosystem of topic-specific reviews, benchmark papers, and software frameworks. The original model no longer serves this field well, and we can no longer sustain it. We therefore change direction. We freeze the Living Review as an archival reference covering the literature up to 1 June 2026, where it remains a stable record of the first phase of HEP-ML. A new resource, the HEP-ML Living Guide, replaces it. It does not list everything. It curates, it annotates, and it points readers to foundational and representative work, so that researchers can find their way into a mature and rapidly diversifying field. In this article we explain why we make this change and how the new resource works.
hep-phhep-exhep-lathep-th+12 citations
31
Prospects for early heavy-quark measurements at the EIC
Allencris John Rubesh Rajan🇫🇷 · Laboni Manna🇵🇱
We assess the prospects for inclusive heavy-quark-pair electroproduction in electron-proton ( $e p$ ) and electron-nucleus ( $e$ A) collisions, alongside double-charm-pair ( $D^{0} D ˉ^{0}$ and $D^{0} D^{0}$ ) electroproduction in $e p$ collisions, during the early operational phase of the Electron-Ion Collider (EIC). Based on the anticipated beam energies and luminosities of the EIC, we estimate the total cross sections and differential distributions for photon virtuality $Q^{2}$ , heavy-quark transverse momentum, and rapidity. This analysis evaluates different Bjorken- $x$ ( $x_{Bj}$ ) intervals across a range of $Q^{2}$ values. Expected event yields are estimated from the projected integrated luminosities of the early science programme, demonstrating the substantial improvement in statistical precision over previous HERA measurements at moderate and large $x_{Bj}$ . For electron--nucleus collisions, we compute the nuclear modification ratio $R^{e A}$ within collinear factorisation using nuclear parton distribution functions, and identify the kinematic regimes in which shadowing, anti-shadowing, and EMC-like suppression are accessible with early EIC data. These results are intended to serve as a parton-level baseline to support feasibility studies and to provide a reference for future higher-order theoretical and experimental investigations at the EIC.
hep-phhep-thnucl-th0 citations
32
NNLO soft functions for heavy-quark pair production at hadron colliders
Guido Bell🇩🇪 · Alessandro Broggio🇦🇹 · Sebastian Edelmann🇩🇪 · Matthew A. Lim🇬🇧 · Rudi Rahn🇦🇹
We generalise the SoftSERVE framework for the automated computation of soft functions involving final-state heavy quarks in back-to-back kinematics up to next-to-next-to-leading order (NNLO) in the strong-coupling expansion. Our algorithm employs suitable phase-space parameterisations for both massive and mixed massless-massive contributions, allowing for an efficient numerical evaluation. Focusing on SCET $_{I}$ observables that satisfy non-Abelian exponentiation, we present explicit results for the 0-jettiness soft function in hadronic top-quark pair production in the form of two-dimensional grids. We describe the renormalisation procedure in detail and discuss the singular behaviour of the tripole colour correlations in the threshold limit.
hep-ph0 citations
33
Leptogenesis in Brane-modified cosmology: Signatures in primordial gravitational waves
Amit Dutta Banik🇮🇳 · Arnab Paul🇮🇳
We investigate the implications of brane-inspired modifications of the evolutionary history of the early universe on the process of baryogenesis via leptogenesis. A modified cosmic history alters the evolution of the Boltzmann equations governing lepton asymmetry, providing the possibility of successful leptogenesis in regions of the parameter space inaccessible in the standard cosmological scenario. Furthermore, a modified cosmic history also alters the shape of an otherwise scale-invariant spectral energy density (SED) of primary gravitational waves (PGWs) produced during inflation. This establishes a novel yet indirect probe of high scale leptogenesis scenarios through the observation of the SED of PGWs via future observations. We consider two scenarios in this work with single and multiple epochs of stiff equation of state(s) after inflation and before the epoch of radiation domination. We identify the parameter space where successful leptogenesis is possible, along with the possible observability of the PGWs, hence providing an indirect window into this leptogenesis scenario through PGWs.
hep-ph0 citations
34
Constraints on magnetic monopoles from X-ray observations of neutron stars
Mainak Mukhopadhyay🇺🇸 · Daniele Perri🇵🇱 · Edward W. Kolb🇺🇸
Magnetic monopoles are captured efficiently by neutron stars, and if they catalyze nucleon decay, the decay products would thermalize and generate observable X-ray surface emission. We use archival Chandra, XMM-Newton, and Swift-XRT data for old isolated millisecond pulsars to place conservative limits on the Galactic monopole flux ( $F_{M}$ ). For a benchmark cross-section of $σ_{Δ B} \sim 1 0^{- 27} c m^{2}$ , our constraint as a function of monopole mass $m_{M}$ is given by $F_{M} (m_{M}) ≲ 6 \times 1 0^{- 19} c m^{- 2} s^{- 1} s r^{- 1} \times max (4 \times 1 0^{- 6}, min (2 \times 1 0^{11} (GeV/ c^{2}) / m_{M}, 1))$ . These limits improve previous neutron-star bounds, provide the strongest constraints to date on $F_{M}$ for $m_{M}$ between $1 0^{11} - 1 0^{13} GeV/ c^{2}$ , and are competitive to existing constraints for this scenario. We also derive complementary constraints from the measured thermal emission of the Magnificent Seven. Our results demonstrate that neutron star X-ray observations provide a powerful probe of magnetic monopoles and motivate dedicated X-ray searches for old neutron stars as a means to test monopole-induced heating.
↳ astro-ph.HEhep-phhep-th0 citations
35
Neutrino quantum kinetics for fast flavor conversion in a time-dependent environment
Zewei Xiong🇩🇪 · Meng-Ru Wu🇹🇼
Fast flavor conversions (FFCs) of neutrinos, driven by the fast flavor instability (FFI), can reshape the neutrino flavor content in dense astrophysical environments such as core-collapse supernovae and neutron star mergers. Most studies of FFCs adopt a two-step approach, in which a flavor-unstable state containing deep electron-minus-heavy-flavor lepton number (E-XLN) angular crossings is first constructed and subsequently evolved. Because realistic crossings should instead develop gradually through neutrino transport, the validity of such setups has been called into question. We investigate this issue by solving the neutrino quantum kinetic equations with self-consistent collisional rates in a spherically symmetric supernova background whose electron fraction evolves in time through a sequence of stages, starting from a configuration free of E-XLN crossings. We find that the evolution proceeds through three characteristic episodes. In the shallow-crossing episode, FFCs develop from marginally unstable, shallow crossings, carrying small-scale structures consistent with linear stability analysis. In the near-crossing-elimination episode, the balance between collisions and FFCs keeps the system in a near-quasistationary state in which the emerging crossings are continuously eliminated, so that the strongly unstable regime is never reached. In the swapping episodes, the E-XLN reverses sign and a dynamically propagating flavor-swap E-XLN zero surface forms. We find that the evolved flavor content at the end of different time stages broadly agrees with the quasistationary solutions obtained in the corresponding two-step models adopting fixed matter backgrounds. In addition, we investigate the robustness of the effective classical transport (ECT) framework that adopts subgrid flavor redistribution using different parametrized prescriptions. Notably, except during the swapping [abridged]
↳ astro-ph.HEhep-ph1 citation
36
Inflationary Axion Isocurvature in the CMB across All Ultralight Masses
Rayne Liu🇺🇸 · Wayne Hu🇺🇸 · Daniel Grin🇺🇸
If the Peccei-Quinn symmetry of an ultralight axion is broken before the end of inflation, axion quantum fluctuations seed isocurvature perturbations, linking them to the tensor-to-scalar ratio $r$ . We extend the effective time average (ETA) approach of the Boltzmann code $AxiECAMB$ to accurately evolve these perturbations across the full axion mass range from dark energy ( $m_{a} ≲ H_{0}$ ) to dark matter ( $m_{a} ≫ 1 0^{- 28}$ eV) types. We provide analytic fitting formulae for the axion abundance given the initial field value $ϕ_{ini}$ , accurate at sub-percent level for $m_{a} ≫ H_{0}$ and allowed dark matter fraction $f_{dm}$ . In the dark matter regime, the Planck bound on CDM isocurvature requires $r f_{dm} < 0.08 (m_{a} /1 0^{- 27} eV)^{- 1/2}$ , which becomes stronger than the current BICEP tensor bound for $m_{a} f_{dm}^{2} ≳ 1 0^{- 26.4} eV$ . For $1 0^{- 32} ≲ m_{a} / eV ≲ 1 0^{- 28}$ , Jeans suppression breaks the degeneracy with CDM isocurvature, leaving unique signatures, and in the dark energy regime ( $m_{a} ≲ H_{0}$ ), the isocurvature signal is even more highly suppressed, peaking only at the CMB quadrupole. We provide analytic scalings for both signatures. Given the tensor bound, any primary CMB detection in these two lightest regimes would indicate a non-inflationary origin of the isocurvature modes or a breakdown of the standard frozen-field misalignment scenario. A window of coexistence opens near $m_{a} \sim 1 0^{- 25}$ eV and $f_{dm} ≳ 0.1$ where both axion isocurvature and tensor modes could be discovered just below current bounds while simultaneously alleviating the $S_{8}$ tension.
↳ astro-ph.COhep-ph0 citations
37
High Precision Fundamental Physics Experiments at JLab with Spin-transparent Storage Rings of Low-energy Polarized Electron Beams
Vladimir Khachatryan · Riad Suleiman · Alberto Accardi · Carlos Ayerbe Gayoso · Marco Battaglieri · Devesh Bhattarai · Silviu Covrig Dusa · Yaroslav Derbenev · Forrest Friesen · Joseph Grames · Paul Guèye · Tyler J. Hague and 17 other authors
A breakthrough in fundamental physics experiments measuring particle spin precession may happen if spin-transparent storage rings become adopted tools for such experiments. We present a new design of highly specialized table-sized storage rings, which use low-energy polarized electron beams and Mott polarimetry. Based on the spin transparency ansatz, the spin precession stemming from the magnetic dipole moment is canceled at any beam energy after an electron's turn along the periodic orbit in the ring. Meanwhile, a spin precession induced by the fundamental physics of interest, e.g., the electron's permanent electric dipole moment (EDM) and/or ultralight-dark-matter-mediated forces such as axions, will accumulate. However, capitalizing on such types of rings is not only desirable for measurements of EDMs and axion searches relevant to $C P$ violation and matter-antimatter asymmetry in the Universe, but may also find very promising applications in quantum computing.
↳ nucl-exhep-phhep-thphysics.acc-ph+10 citations
38
The explicit Lorentz invariant QED pair production rates from superstrings
J. X. Lu🇨🇳
We present a new avenue to the usual Schwinger effect via the open string pair production for a system of two Dp branes with $1 \leq p \leq 6$ in Type II superstrings. The two Dp are placed parallel at a separation with one of them carrying the most general constant electromagnetic background allowed for the pair production. By taking the so-called field theory limit, we obtain systematically, from the open string pair production rate, the respective \textit{explicit Lorentz invariant} QED pair production rate in diverse dimensions for a pair of charged/anti-charged massive particles, which can be scalars, spinors or vectors.
↳ hep-thgr-qchep-phmath-ph+10 citations
39
Matrix Multiverses Meet Multiple Mythologies
Sidan A🇺🇸 · Tom Banks🇺🇸 · Willy Fischler🇺🇸
We present a model in which asymptotically de Sitter universes of various types, and de Sitter (dS) radii $R_{n}$ , live in the interiors of black holes in a maximally entropic flat $p = ρ$ Friedmann-Robertson-Walker universe. These dS universes clearly have many quantum states. We argue that they decay and equilibrate with the maximal entropy universe on time scales of order $α_{n} R_{n} ln (R_{n} / δ_{n})$ , where $α_{n}$ are model-dependent dimensionless constants and $δ_{n}$ are the initial distances between the shell, satisfying the Israel junction conditions, and the dS horizon. These are time-scales as viewed by a detector following a trajectory far from the would-be cosmological horizon. These times are all exponentially shorter than dS recurrence times, which have no meaning in this model. It is impossible for a detector inside one of the dS universes to determine whether it is actually part of such a structure. This model could be used as the basis for claiming that certain constants of nature or cosmological initial conditions were chosen to have mathematically unnatural values because other values could not lead to any form of intelligent life.
↳ hep-thgr-qchep-ph1 citation
40
Geodesic structure, eikonal quasinormal modes and thermodynamic properties of a Schwarzschild-de Sitter-like black hole with global monopole in Bumblebee gravity
Irengbam Roshila Devi🇮🇳 · Yenshembam Priyobarta Singh🇮🇳 · Dhruba Jyoti Gogoi🇮🇳 · Telem Ibungochouba Singh🇮🇳
We investigate the geodesic dynamics, eikonal quasinormal modes (QNMs), and extended phase space thermodynamics of a Schwarzschild-de Sitter-like black hole coupled with a global monopole in Bumblebee gravity. Our analysis reveals that spontaneous Lorentz symmetry breaking and topological defects modify the effective radial dynamics, leading to lower effective potential barriers and a reduced magnitude of the effective force. For null geodesics, higher monopole parameters expand the photon sphere and critical impact parameter, implying an enlarged black hole shadow, while mitigating dynamical instability. For massive particles, the stable circular orbit window narrows significantly as the Outermost Stable Circular Orbit (OSCO) shrinks, alongside a marked enhancement in perihelion precession. In addition, we examine the correspondence between the eikonal QNMs and the properties of null geodesics. The excellent agreement between the eikonal approximation and the WKB method for scalar and electromagnetic perturbations supports the validity of the correspondence for the spacetime under consideration. In the extended thermodynamic phase space, we evaluate the black hole as a holographic heat engine. We demonstrate that classical efficiency is mathematically blind to Lorentz violation; however, introducing a quantum-corrected modified entropy tightly couples the macroscopic work output to the symmetry-breaking framework. Ultimately, the necessity to respect the Carnot bound imposes a strict macroscopic constraint on the Lorentz-violating parameter, safeguarding the Second Law of Thermodynamics.
↳ gr-qchep-ph0 citations
41
Schwinger-Keldysh effective field theory of type-B Goldstone: near-diagonal geometry and Berry term
Pei Zheng🇨🇳 · Mei Huang🇨🇳
In this work, we formulate a finite temperature Schwinger-Keldysh effective field theory for type-B Goldstone modes. In particular, we organize the required two time contour structure by a near-diagonal geometry in which the r-type field is interpreted as the physical Goldstone configuration and the a-type field is identified as corresponding tangent displacement. Within this geometric viewpoint, the Berry term essential for type-B Goldstones is obtained directly through the transgression of the Berry curvature. Moreover, we show that this exact Berry transgression is compatible with dynamical KMS condition. In order to construct the conservative, dissipative and noise sectors, we classify possible tensors globally defined on the coset manifold. Based on this framework, we discuss in detail two concrete model examples. The dispersion relations of the Goldstone modes and the associated two-point correlation functions are calculated in the presence of dissipation.
↳ hep-thhep-ph0 citations
42
Thermal Origin of Black Hole Quasinormal Modes
D. Giataganas🇹🇼 · G.F. Giudice🇦🇪 · A. Kehagias🇬🇷 · F. Quevedo🇦🇪 · A. Riotto🇨🇭
When a black hole rings after a merger, it emits gravitational waves at characteristic frequencies known as quasinormal modes (QNMs). In the eikonal limit, these modes are governed by the unstable circular light orbits that form the photon ring. In this work, we demonstrate that the ringing of a black hole has a precise thermal interpretation. A probe string propagating in the near-ring geometry acquires an induced Rindler horizon on its worldsheet, with a temperature set by the Lyapunov exponent of the photon ring. Out of this structure, the black hole QNMs emerge as thermal excitations, so that the characteristic ringing of a black hole is the retarded response of a thermal system living on the photon ring. We explicitly derive the QNM spectrum from two complementary perspectives: microscopically, via unstable transverse worldsheet fluctuations, and macroscopically, through the pole structure of the causal response function of an open thermal quantum system.
↳ hep-thastro-ph.COgr-qchep-ph1 citation
43
Probing ultralight bosons with LISA observations of spinning black hole mergers and follow-up searches of merger remnants
Ifigeneia Giannakoudi🇨🇦 · Maxence Corman🇩🇪 · William E. East🇨🇦
Ultralight bosons can trigger superradiant instabilities around rotating black holes, extracting angular momentum and leading in some cases to observable gravitational signatures. When the associated spin-down timescale is shorter than the black hole lifetimes and the spin-up timescales due to, e.g. accretion, this process imposes an upper limit on black hole spins. In addition, the formation and subsequent dissipation of boson clouds generates quasi-continuous gravitational wave emission. In this work, we explore the prospects for constraining and detecting ultralight bosons with observations of massive black hole binary mergers with the space-based LISA observatory. We consider two complementary approaches: measurements of black hole spins from merging binaries and follow-up gravitational wave searches targeting massive black hole binary merger remnants. We consider three population models for massive black holes, based on either heavy or light seeds, and forecast the exclusion and detection probabilities for both scalar and vector bosons. We find that black hole spin measurements can constrain scalar masses in the range $[5 \times 1 0^{- 18}, 1 0^{- 14}]$ eV and vector masses in the range $[6 \times 1 0^{- 19}, 2 \times 1 0^{- 14}]$ eV, with the exact range depending on the model. In contrast, restricting to vector bosons, follow-up gravitational wave searches are sensitive to a narrower vector boson mass range of $\sim [3 \times 1 0^{- 17}, 3 \times 1 0^{- 15}]$ eV, with the specific values again depending on the model. If a vector boson with a mass in the range $[1 0^{- 16}, 2 \times 1 0^{- 15}]$ eV existed, the probability of having an event that the follow-up searches would be sensitive to ranges from very small to near unity depending on the astrophysical model.
↳ gr-qcastro-ph.HEhep-ph1 citation
44
The Fate of Large Scale White Noise in Second-Order Cosmological Perturbation Theory
Aurora Ireland🇺🇸
Working to second order in cosmological perturbation theory, we reconsider the Large Scale White Noise (LSWN) effect proposed in [2511.13866] and [2511.15803]. We demonstrate that the kurvature density variable $Δ ρ$ does indeed develop LSWN at second order. However, contrary to the claims of [2511.15803], we show that this is not inherited as an infrared (IR) pole in the second-order comoving curvature perturbation $R_{2}$ . This apparent enhancement was an artifact of using a linear Poisson equation to relate two genuinely second order quantities. Further, we show that $R_{2}$ is protected from developing any such IR enhancement: $lim_{k \to 0} (k^{2} R_{2}) = 0$ , which follows from a conservation law in the soft limit. The constraint proposed in [2511.15803] and its implications for the small-scale primordial power spectrum are therefore invalid.
↳ astro-ph.COgr-qchep-phhep-th1 citation

Affiliations

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