HEP Phenomenology·hep-ph

Fri·Jul 24, 2026Friday·July 24, 2026

34 papers—18 primary·16 cross-listed

01
Unveiling the Vanishing Higgsino-Nucleon Scattering in the MSSM at Next-to-Leading Order
Subhadip Bisal🇨🇳 · Arindam Chatterjee🇮🇳 · Debottam Das🇮🇳 · Syed Adil Pasha🇮🇳 · Rahul Puri🇮🇳
Higgsino dark matter (DM) is considered one of the most well-motivated and minimal DM scenarios arising from supersymmetric extensions of the Standard Model. Motivated by the requirement of electroweak naturalness, Higgsinos are expected to be relatively light, with masses close to the weak scale. While a pure Higgsino state typically evades current direct detection limits, next-to-leading (NLO) order radiative corrections may bring it within the sensitivity of upcoming experiments. On the contrary, a more important consequence, observed specifically near the kinematic threshold for the production of two particles, is that the NLO corrections lower the DM-nucleon cross section below the neutrino floor. We explicitly examine the cancellation mechanism responsible for suppressed Higgsino-nucleon scattering and identify regions of MSSM parameter space where spin-independent cross-sections may vanish.
hep-ph3 citations
02
Accidentally Stable Dark Matter in a Parity Solution to the Strong CP Problem
Matthew J. Baldwin🇺🇸 · Keisuke Harigaya🇺🇸 · Isaac R. Wang🇺🇸
Parity symmetry, with an extended gauge group $S U (3)_{c} \times S U (2)_{L} \times S U (2)_{R} \times U (1)_{X}$ , can solve the strong CP problem. In particular, the model where $S U (2)_{R} \times U (1)_{X}$ is broken by the Parity partner of the Standard Model Higgs solves the strong CP problem without the necessity of introducing extra symmetry. We discuss the possibility of accidentally stable dark matter in this framework and show that $S U (2)_{L} \times S U (2)_{R}$ bi-triplet fermions can be stable over cosmological timescales. We compute the relic abundance of the bi-triplet dark matter and derive constraints on the parameter space from collider, direct-detection, and indirect-detection experiments. The $S U (2)_{R} \times U (1)_{X}$ symmetry breaking scale is required to be below 150 TeV, and most of the parameter space can be probed by near-future indirect-detection experiments.
hep-ph2 citations
03
Earth rotation turns event timing into a geometric probe of UHE neutrino origin
Andrew Cheek🇨🇳 · João Paulo Pinheiro🇨🇳 · Jordi Salvado🇪🇸
It has been proposed that the ultra-high-energy (UHE) event $KM3 - 230213A$ detected by KM3NeT could be explained by dark matter (DM) decay. Prima facie this seems unlikely because the arrival direction of the event is opposite to the Galactic Centre. We develop a per-event test statistic to quantitively assess this possibility and forecast the required future events to exclude the DM hypothesis in favour of an isotropic signal. For the single event observed, the DM decay hypothesis is disfavoured but not excluded ( $p -value_{DM} ≃ 0.13$ -- $0.15$ ). We emphasise how including the time-averaged detector visibility helps discrimination despite reducing the proportion of visible sky, reducing the number of events for exclusion from $\sim 33$ -- $43$ to $\sim 22$ -- $27$ . Moving beyond this, we perform a fully time-resolved forecast and find that the required number of events for exclusion reduces by $40%$ , $\sim 14$ -- $16$ . The time variation in the signal provides vital information allowing one to exclude or confirm the DM hypothesis with much fewer events. Our results are robust against DM decay channels and halo distributions and can readily be applied to other relics distributed similarly. Our framework allows one to turn event timing into a probe of signal geometry and is generic to any UHE equatorial neutrino telescopes.
hep-phastro-ph.HE0 citations
04
Dark Matter Weather: Probing Sub-GeV Interactions with Earth-Shielding Modulation
Tetiana Kozynets🇩🇰 · Rebecca Leane🇺🇸 · Juri Smirnov🇬🇧
Daily modulation from Earth shielding provides a powerful search handle for sub-GeV dark matter (DM) in low-threshold experiments. We use this effect as a probe of interaction structure in scenarios where DM couples to both electrons and nuclei. Nuclear scattering in the Earth alters the incident DM flux, while electron scattering produces the observable ionization signal, so the total rate and modulation pattern encode different aspects of the underlying interactions. We develop this two-interaction framework for argon and xenon targets and introduce a new statistical analysis that tests the modulation shape, including the location-dependent exposure of underground detectors to different Earth-crossing trajectories, alone and in combination with the ionization spectrum. We demonstrate the method for liquid-noble detectors at underground sites SURF (USA), LNGS (Italy), and SUPL (Australia), and apply it to DarkSide-50 data as a concrete case study. Our results show that Earth-scattering modulation can help disentangle electron and nuclear DM interactions and provide a validation handle for low-threshold liquid-noble searches.
hep-phastro-ph.HEhep-ex0 citations
05
Reheating the FCC: Probing Early Matter Domination with Long-Lived Particles
Nicolás Bernal🇦🇪 · Giovanna Cottin🇨🇱 · Kuldeep Deka🇦🇪 · Manuel López🇨🇱
We study a GeV-scale Higgs-portal scalar $ϕ$ that can dominate the early Universe and later decay into Standard Model states, ending an early matter-dominated era. Ordinary cosmic reheating is the minimal example of this scenario. The small Higgs mixing makes $ϕ$ a long-lived particle (LLP), linking the reheating temperature $T_{rh}$ to displaced-decay signatures at colliders. Including finite-temperature suppression of the decay width, we map FCC-hh LLP sensitivity onto the $[m_{ϕ}, T_{rh}]$ plane. We find that FCC-hh displaced searches could probe GeV-scale transition temperatures, up to the electroweak scale within the broken-phase Higgs-portal description.
hep-phhep-ex0 citations
06
Hyperasymptotic Expansions in QCD: The Lightest Gluelump Mass Case
Antonio Pineda🇪🇸
In these proceedings, we provide a summary of our recent advancements in determining the mass of the lightest gluelump using hyperasymptotic expansions in Quantum Chromodynamics (QCD) \cite{Ayala2025}. This paper details our methodology, our precise determination of leading renormalon normalization constants, and our extraction of the gluelump mass from two independent physical systems, yielding a final combined, renormalization-group-invariant and scheme-independent result of $Λ_{B}^{PV} = 2.44 (7) r_{0}^{- 1}$ .
hep-phhep-lathep-th0 citations
07
Spin Structure of the Nucleon: Overview
Yoshitaka Hatta🇺🇸
I present a pedagogical review of the decomposition of the proton spin. Both the Jaffe-Manohar and Ji decompositions are discussed. Particular emphasis is placed on the quark and gluon orbital angular momenta, including their gauge invariant definitions, small- $x$ behavior and connection to experimental observables.
hep-ph2 citations
08
Numerical Backreaction and Finite-Time Energy Transfer in Post-Recombination Magnetogenesis from Ultralight Dark Matter
Aviv David🇨🇦 · Robert Brandenberger🇨🇦
We study gauge-field production in a post-recombination magnetogenesis scenario driven by an ultralight pseudoscalar dark matter field $ϕ$ coupled to electromagnetism. Previous analytical work has shown that a homogeneous oscillating $ϕ$ background can excite gauge field modes through tachyonic and narrow-band resonance channels. Here we follow the coupled evolution of the homogeneous $ϕ$ mode and gauge field modes of both helicities in an expanding background. Our numerical work confirms the results for the spectra of produced gauge particles obtained in the previous approximate analytical treatments. In addition, our study allows us to determine when back-reaction shuts off the resonance. We find that for parameter values for which the tachyonic instability band is open, back-reaction does not shut off the resonance until a fraction $F$ of order one of the initial dark matter energy density has been transferred to photons, and this happens on a time scale which is short compared to the Hubble time. In the parameter range in which only the narrow resonance band is open, $F$ eventually reaches order one, but the time when this happens increases as the effective coupling constant decreases, and therefore $F$ may remain negligible until the present time.
hep-phastro-ph.COgr-qchep-th0 citations
09
The $K (1690)$ signal from COMPASS as a strange hybrid state
Bing Chen🇨🇳 · Ri-Qing Qian🇨🇳 · Xiang Liu🇨🇳
A pseudoscalar resonance structure, denoted as the $K (1690)$ , was recently discovered by the COMPASS Collaboration in the scattering reaction $K^{-} + p \to K^{-} π^{-} π^{+} + p$ . If the $K (1690)$ is a genuine state, there are three observed pseudoscalar strange mesons, namely the $K (1460)$ , $K (1690)$ , and $K (1830)$ , in the 1.0 $-$ 2.0 GeV region. However, within the conventional quark model, only the $2^{1} S_{0}$ and $3^{1} S_{0}$ strange meson states are expected in this energy region. Therefore, at least one of these states should be interpreted as an exotic candidate. In this work, we study the spectrum of strange mesons systematically, and find that the $K (1460)$ and $K (1830)$ are good candidates of $2^{1} S_{0}$ and $3^{1} S_{0}$ strange mesons, respectively. A further investigation of their strong decays also supports this assignment. Furthermore, we note that the production mechanism of the $K (1690)$ is similar to that of the $π_{1} (1600)$ , which has been widely regarded as a hybrid meson candidate. We investigate the strong decays of the $K (1690)$ within a constituent gluon model by treating it as a $0^{-}$ strange hybrid meson and find that the results support the $K (1690)$ as a hybrid state. Finally, we identify several important decay modes of the $K (1690)$ that may be used in future experiments to test whether it contains the $n^{1} S_{0}$ ( $n =$ 2 and 3) $s q ˉ$ component. We also suggest BESIII to search for the $K (1690)$ state through the $J / ψ \to K K (1690) \to K K_{0}^{*} (1430) π \to K K π π$ process.
hep-ph0 citations
10
Dark Monopoles, Bounds on Hidden Sectors, and Cosmological Implications
Donald Liveoak🇺🇸 · Anshuman Maharana🇮🇳 · James D. Wells🇺🇸
Hidden sectors are a generic prediction of string theory compactifications and result in a promising landscape for dark matter model building. We consider the case of hidden sector magnetic monopoles produced via a thermal phase transition in the early Universe and subsequently diluted by pair annihilation. We show that for symmetry-breaking scales $≳ 100 PeV$ , the monopole abundance is unacceptably high, overclosing the Universe. Our bounds are robust against variations in the initial fraction of energy density deposited in the hidden sector, exhibiting only a weak power-law dependence on this quantity. The bound is substantially tightened in the case of multiple hidden sectors. The standard cosmology may only be recovered if one of the following is true: the hidden sector(s) are non-existent, the hidden sectors have no monopoles with symmetry-breaking scale above 100 PeV, the maximum temperature of each monopole-producing hidden sector after reheating is below its symmetry-breaking scale, or the monopole abundance is diluted during a period of early matter domination.
hep-phastro-ph.CO1 citation
11
Charged Higgs Search at Future Neutrino Telescope and Higgs Factory
YiCheng Dai🇨🇳 · Wei Liao🇨🇳 · Yi-Song Lu🇨🇳 · Qi-Shu Yan🇨🇳
We investigate the discovery potential of the charged Higgs boson at future lepton colliders and neutrino telescopes within two simplified benchmark scenarios with universal Yukawa couplings. We demonstrate that both the muon-track and cascade events at neutrino telescopes can be exploited to search for or constrain the charged Higgs boson through resonant neutrino scattering process, and we compare the sensitivities obtained under different astrophysical neutrino flux models. We study the effect of the detector volume of neutrino telescopes on the discovery potential of the charged Higgs boson. We study the signal of charged Higgs boson at future lepton colliders over different kinematic regimes using optimized reconstruction strategies. We compare the discovery potential of the two experimental approaches over the relevant parameter space and find that future lepton colliders generally provide better sensitivity in most of the parameter space, while neutrino telescopes with very large detector volume can offer competitive and complementary sensitivity in the heavy-mass region of the charged Higgs boson.
hep-phastro-ph.HEhep-ex0 citations
12
Advanced Statistical Analysis of Linear and Nonlinear Regge Trajectories for Light Non-strange Mesons
S.S. Afonin🇷🇺
A rigorous statistical analysis of Regge-type trajectories for light non-strange meson mass spectra is carried out, which explicitly accounts for experimental uncertainties. We test three scenarios: a linear model with distinct radial ( $n$ ) and orbital ( $l$ ) slopes (Model 1), a linear model with a universal slope (Model 2), and a nonlinear model featuring a universal slope and a Dirac-Coulomb-type term $\propto (l + 1)^{- 1}$ (Model 3). Optimization is performed using a nonlinear $χ^{2}$ minimization framework, where the intrinsic theoretical model uncertainty is determined self-consistently by enforcing $χ^{2} / dof = 1$ . To ensure robust model selection, we employ the Akaike and Bayesian information criteria alongside complementary statistical tests. Our analysis demonstrates that moderate deviations from linearity in the Regge spectrum are predominantly localized within the $S$ -wave resonance sector. These distortions are successfully accommodated by the nonlinear correction in Model 3, from which an approximate Coulomb-type degeneracy, $m^{2} (n, l) \propto n + l$ , emerges as a statistically robust feature. Furthermore, we show that the $l$ -dependent correction to the principal quantum number in light non-strange mesons is consistent with the leading-order relativistic correction to the Coulomb problem.
hep-phhep-exhep-thnucl-th0 citations
13
MeV Electrophilic Axion-like Particles from Sun
Shao-Feng Ge🇨🇳 · Sk Jeesun🇨🇳 · Tao Li🇨🇳
This work explores the production of an MeV-scale electrophilic axion-like particles (ALPs) by utilizing the monochromatic 5.5MeV photon resulting from the nuclear fusion processes in the Sun. These 5.5MeV photons can undergo the Compton-like scattering with the ambient electrons in the solar matter to produce a substantial flux of MeV ALPs. Upon reaching the Earth, such ALPs can be detected via the same electron coupling, offering a new opportunity for the dark matter (DM) direct detection experiments to probe the previously unexplored parameter regions. We show that the existing data of LZ, PandaX-4T, and Borexino can attain the sensitivities $g_{a e} ≲ 3.7 \times 1 0^{- 6}$ , $g_{a e} ≲ 3.7 \times 1 0^{- 6}$ and $g_{a e} ≲ 1.7 \times 1 0^{- 6}$ , respectively, for $m_{a} ≲ 1$ MeV. An optimistic 200 tonne $\times$ year exposure by PandaX-xT can reach $g_{a e} ≲ 1.6 \times 1 0^{- 6}$ for most of the mass window $m_{a} < 1$ MeV and even $g_{a e} ≲ 1.5 \times 1 0^{- 7}$ with $m_{a}$ approaching 1MeV. Despite the stringent constraints from different laboratory experiments and astrophysical observations, our obtained limits from LZ, PandaX-4T, and Borexino can probe new parameter regions, specifically in the mass window $0.4 MeV ≲ m_{a} ≲ 1$ MeV.
hep-phastro-ph.HEastro-ph.SRhep-ex0 citations
14
Thermal Resummation for Very Strong First-order Phase Transitions
Philipp Klose🇳🇱
Effective potentials are a key ingredient for predicting stochastic gravitational wave backgrounds from strong first-order phase transitions in the early universe. Established techniques for a robust computation, including dimensional reduction, rely on a high-temperature expansion that is expected to break down for very strong transitions capable of producing observable backgrounds at next-generation gravitational wave detectors such as LISA. We argue that existing 2PI effective action techniques enable consistent resummation for such transitions, and use them to compute the next-to-leading order effective potential of the Abelian Higgs model for a strong transition in a general covariant gauge. We find that our result can be recovered from a Daisy resummed potential by modifying the power counting, and show explicitly that it satisfies the leading-order Nielsen identity needed for gauge-independent predictions of the bubble nucleation rate and is consistent with prior results for small Higgs condensates.
hep-ph2 citations
15
Transverse-momentum resummation effects on angular coefficients in Z and W boson hadroproduction
Stefano Camarda🇨🇭 · Giancarlo Ferrera🇮🇹 · Lorenzo Rossi🇮🇹 · Gabriele Francesco Sala🇮🇹
We present a comprehensive analysis of the angular coefficients of $Z$ and $W$ boson production at hadron colliders in different kinematical ranges, using data from the ATLAS, LHCb, and CMS Collaborations at the LHC, as well as CDF data at the Tevatron. We provide theoretical predictions obtained by consistently combining the resummation of logarithmically enhanced QCD corrections at small transverse momenta $q_{T}$ up to next-to-next-to-leading logarithmic accuracy (NNLL) with fixed-order calculations at next-to-leading order (NLO), valid at large $q_{T}$ . We quantify the impact of transverse-momentum resummation on the angular coefficients. We find that the inclusion of resummation effects leads to a moderate and systematic improvement in the description of the data in the intermediate $q_{T}$ region, $q_{T} \sim 20 - 50$ ~GeV, for several angular coefficients, while in the remaining cases it does not degrade the agreement of fixed-order QCD predictions with experimental measurements.
hep-phhep-exhep-lat0 citations
16
Heavy neutral leptons from light scalar in fixed target and forward search experiments
ShivaSankar K.A. · Souvik Das · Arindam Das · Sanjoy Mandal🇰🇷
The observation of neutrino masses strongly motivates $U (1)_{B - L}$ extensions of the Standard Model, in which heavy neutral leptons acquire Majorana masses through spontaneous $U (1)_{B - L}$ symmetry breaking and generate light neutrino masses via the seesaw mechanism. In this framework, the singlet scalar responsible for symmetry breaking mixes with the SM Higgs boson, allowing it to be produced in rare meson decays. We investigate a scenario in which this light scalar promptly decays into a pair of long-lived heavy neutrinos that subsequently decay into visible charged leptons and hadrons through light-heavy neutrino mixing inside the proposed Forward Physics Facility (FPF) at the FCC-hh and the SHiP beam-dump experiment. Taking into account realistic detector geometries, decay probabilities, and visible branching fractions, we estimate the projected sensitivities to the scalar-Higgs mixing angle as a function of the scalar mass and to the light-heavy neutrino mixing as a function of the heavy neutrino mass. We find that FPF and SHiP can significantly extend the discovery reach for both light scalars and long-lived heavy neutrinos beyond existing experimental limits, providing powerful and complementary probes of neutrino-mass generation and hidden-sector physics.
hep-ph0 citations
17
Neural solutions of coupled ghost and gluon Dyson--Schwinger equations in Landau gauge
Rodrigo Carmo Terin🇪🇸
The coupled ghost and gluon Dyson--Schwinger equations (DSEs) of four-dimensional Landau-gauge Yang--Mills (YM) theory are solved with a neural representation trained only from renormalized equation residuals. The neural and fixed-point solutions agree at the percent level and remain stable under changes of initialization, network size, integration grid, and infrared boundary condition. Variations of the three-gluon vertex model produce substantially larger effects than the neural error. The MiniMOM ultraviolet running and the sign change of the gluon Schwinger function are also reproduced within the limitations of the truncation.
hep-phcs.LGhep-lathep-th0 citations
18
Gauge coupling beta functions and gauge field anomalous dimensions at four loops in the Standard Model
M.A.Bezuglov🇩🇪 · B.A.Kniehl🇩🇪 · V.N.Velizhanin🇩🇪
We present the beta functions of the gauge couplings and the anomalous dimensions of the gauge fields in the unbroken phase of the Standard Model at four loops.
hep-phNPB(2026)·0 citations
19
Chiral Magnetic Conductivity in the Tight-Binding Model of Dirac Semimetals
Mustafa Bohra · Yuexiang Zhang · M.A. Zubkov🇮🇱
We consider the typical tight - binding model of Dirac semimetal in the presence of both magnetic and electric fields. The electric conductivity reveals dependence on magnetic field. We calculate this dependence in the limit of strong magnetic field, when the given model is described effectively by the one - dimensional SSH model because the dynamics in the plane orthogonal to magnetic field is reduced to that of the lowest Landau level (LLL). Considering the small temperature limit we take into account dissipation due to scattering on impurities. The corresponding dissipation rate is calculated explicitly. The obtained results confirm that the source of the magnetoconductivity in this system is chiral magnetic effect.
↳ cond-mat.mes-hallhep-ph0 citations
20
Interacting Dark Energy and Dark Matter in O(3) No-Scale Gravity
Lincoln da S. Pereira🇧🇷 · Muzi Hong🇯🇵 · Elisa G. M. Ferreira🇯🇵 · Tsutomu T. Yanagida🇯🇵
Dark Energy (DE) and Dark Matter (DM) are among the greatest mysteries in particle physics and cosmology, since their origins remain unclear. It is intriguing to consider whether both may originate from a purely gravitational sector. We propose that they arise from degrees of freedom associated with the partners of the Brans-Dicke boson in No-Scale Gravity, a fundamental scale-invariant gravitational theory in which the Planck scale is illusional. We consider the Brans-Dicke boson, together with two scalar fields, to form a vector multiplet under an $O (3)$ symmetry, whose angular directions in the Einstein frame are identified with DM and DE. Small explicit breaking of $O (3)$ generates their masses and interaction, and we show that the resulting model reproduces the required background cosmological evolution and present-day abundances, with the lighter field providing a dynamical DE component at late times. Although the DE field remains canonical, the interacting cosmology exhibits an effective phantom-like evolution at late times, of the type suggested by DESI in combination with other cosmological probes, without introducing a fundamental phantom degree of freedom. The model provides a first-principles realization of interacting DE, in which DM, DE, and their coupling emerge from the symmetry structure of the underlying gravitational theory.
↳ astro-ph.COgr-qchep-phhep-th2 citations
21
Moduli-Space Laplacians, Asymptotic Geometry, and the Emergent String Conjecture
Christian Aoufia🇪🇸 · Muldrow Etheredge🇩🇪 · Bernardo Fraiman🇪🇸 · Sanjay Raman🇺🇸 · Alexander Stewart🇺🇸
At asymptotic limits of moduli spaces of quantum gravity vacua, we argue that the masses of the lightest particle towers are eigenfunctions of the moduli-space Laplacian. The associated eigenvalues are quantized by the Emergent String Conjecture and determine the exponential decay rates of axionic directions in these limits. We also connect the quantization of Laplacian eigenvalues to the spectrum of instantons for the theory. We support our claims with diverse examples that preserve between 4 and 32 supercharges.
↳ hep-thhep-ph2 citations
22
Perturbatively Stable Self-Correcting Classical Memory from Gauge Averaging
Ryan Thorngren🇺🇸
We show that the self-correcting memory in 3d Wegner gauge theory is stable to arbitrary small enough perturbations of the Hamiltonian. Our proof relies on a new method we dub ``gauge averaging'', which gives conditions under which explicitly broken gauge symmetries are effectively restored by fluctuations. These conditions show that the self-correcting memory phase is fluctuation stabilized, with its robustness to perturbations increasing with increasing temperature, up to some $T_{c} > 0$ .
↳ quant-phcond-mat.stat-mechcond-mat.str-elhep-ph+20 citations
23
What could an emerging Big Bang Nucleosynthesis discrepancy be hinting at?
Vivian Poulin🇫🇷 · Julien Froustey🇪🇸 · Cyril Pitrou🇫🇷 · Tristan L. Smith🇺🇸
The latest measurement of the primordial deuterium abundance is in $\sim 2 σ$ tension with several state-of-the-art predictions of standard Big Bang nucleosynthesis (BBN), when using the baryon density inferred from the $Λ$ CDM model fit to cosmic microwave background (CMB) data. This tension increases to $\sim 3 σ$ for models attempting to solve the Hubble tension, such as early dark energy (EDE), which generally predict a larger baryon density than in $Λ$ CDM. We test whether this discrepancy could be pointing to a non-standard expansion history during BBN. We compute light-element abundances with PRIMAT and compare $Λ$ CDM, a $Δ N_{eff}$ extension, and a very early dark energy (vEDE) component. For vEDE, we sample $Δ H / H$ , the fractional increase of the expansion rate while deuterium burning is freezing out and helium-4 fusion is mostly over. The Bayesian analysis using BBN plus the CMB baryon-density constraint in the EDE cosmology gives $Δ H / H = 0.08 7_{- 0.037}^{+ 0.036}$ during the deuterium burning epoch, i.e. at a temperature $T_{D} ≃ 0.03 MeV$ , and no residual tension. The vEDE component preserves the observed deuterium abundance at the larger CMB baryon density while only mildly affecting helium-4. By contrast, extra radiation raises the helium-4 abundance too efficiently and does not reconcile the baryon density determinations. Together with inflation, dark energy, and EDE, our results hint at the presence of another light scalar field in cosmology.
↳ astro-ph.COhep-ph0 citations
24
The Well-Tempered Likelihood: Honest Confidence Intervals for Misspecified Models
Benjamin Nachman🇺🇸 · Jesse Thaler🇺🇸
Likelihood-based inference in particle physics, and in the physical sciences more broadly, relies on the assumption that the model accurately describes the data. When the model is misspecified, though, standard confidence intervals shrink to zero width with increasing data, producing overconfident and potentially misleading constraints. We propose the well-tempered likelihood, which divides the likelihood-ratio test statistic by a goodness-of-fit (GOF) statistic evaluated at the best-fit point. Under correct specification, the GOF is $O (1)$ and standard inference is recovered. Under misspecification, both the likelihood and the GOF scale as $O (N)$ for $N$ data points, so their ratio remains $O (1)$ and the resulting well-tempered confidence interval self-limits at a floor determined by the model's inadequacy, essentially reducing the effective sample size. In other words, \textit{all models are correct, as long as your dataset is small enough}. We present binned and unbinned formulations of the well-tempered likelihood---the latter based on a classifier two-sample test---and demonstrate our method on a Gaussian example and on a measurement of the strong coupling constant using synthetic electron-positron collisions.
↳ stat.MEhep-exhep-phphysics.data-an0 citations
25
Multi-Spin Perturbations, Thermodynamics, and Observational Signatures of Reissner-Nordstrom Black Holes in Bumblebee Gravity
Jayasri Choudhury🇮🇳 · Yenshembam Priyobarta Singh🇮🇳 · Dhruba Jyoti Gogoi🇦🇿 · Telem Ibungochouba Singh🇮🇳
In this paper, we present a comprehensive investigation into the dynamical and thermodynamic properties of the charged Reissner-Nordström (RN) black hole (BH) in the bumblebee gravity framework, where spontaneous Lorentz symmetry breaking (LSB) occurs. To analyze the dynamical behavior, we apply the unified Teukolsky master equation within the Newman-Penrose formalism to evaluate massless field perturbations of arbitrary spins ( $s = 0, 1/2, 1, 3/2, 2$ ). By deriving the corresponding effective potentials, we compute the quasinormal modes (QNMs) frequencies using the Padé-improved 6th-order WKB approximation and the Asymptotic Iteration Method (AIM) and evaluate the greybody factors for all perturbing fields, demonstrating how the LSB parameter $L$ and the BH charge $Q$ modify the spacetime's damped oscillations and wave propagation. We further assess the observational prospects of these QNMs by determining the black-hole mass ranges accessible to current and future gravitational-wave detectors, including LISA, Virgo, and LIGO. Moreover, we investigate the modified thermodynamic structure, calculating the Hawking temperature, entropy with logarithmic thermal corrections and heat capacity. Our thermodynamic analysis reveals a second-order phase transition whose critical radius is heavily governed by the background charge. These combined findings provide valuable theoretical insights into how Lorentz violation affects the physical stability, thermal evolution, and phase structure of charged BHs.
↳ gr-qchep-ph2 citations
26
A lower bound on primordial power spectrum from halo substructure
Shin'ichiro Ando🇳🇱 · Nagisa Hiroshima🇯🇵 · Koji Ishiwata🇯🇵 · Tomo Takahashi🇯🇵
We investigate how the primordial curvature perturbation of a certain wavelength scale affects the halo and subhalo structure. Primordial power spectrum considered in this paper features a nearly scale-invariant form with a cutoff at the wavenumber $k = O (1)$ Mpc $^{- 1}$ and an additional log-normal bump at smaller scales. We compute the host halo evolution, as well as the subhalo mass function. To be consistent with the observations of stellar streams and gravitational lensing data, the amplitude of the bump that is typically the same or larger than $1 0^{- 9}$ of the primordial curvature perturbation should be present at the wavenumbers of $10$ - $30$ Mpc $^{- 1}$ .
↳ astro-ph.COastro-ph.GAhep-ph0 citations
27
Searching for initial state fluctuations in heavy ion collisions at FAIR energy using Principal Component Analysis
Ekata Nandy🇮🇳 · Subhasis Chattopadhyay🇮🇳
In high energy heavy ion collisions, the initial configurations of the colliding nuclei play an important role in determining the reaction type and the products of the reaction. The initial arrangement of nucleons within the overlap region of two colliding nuclei is generally asymmetric and such asymmetries reflect themselves in the measurement final state momentum anisotropy. Also initial distribution of the nucleons are subjected to large quantum fluctuation causing large energy deposition in a small region. The final state observables related momentum anisotropies although sensitive to such localized fluctuations but their true effect gets diluted because these observables are calculated by averaging over a set of events. Also, such fluctuations in the initial states are random and uncontrolled. Thus, identifying their effect from event-averaged final state observable is difficult. However, it would be interesting to know the origin of such fluctuations and how these fluctuation are eventually translated to the final state. In this work, we at first introduce such localized fluctuations in the initial configurations, also called hot spots, by implementing spatial rearrangements of nucleon position in the colliding nuclei in the central Pb+Pb collisions at E $_{l ab}$ =20 AGeV ( $s$ =6.27 GeV) using the UrQMD event generator. Then the final state distributions of one or two dimensional variables e.g., ( $η$ , $ϕ$ , $p_{T}$ ) and ( $η - p_{T}$ , $ϕ - p_{T}$ , $η - ϕ$ ) of the produced pions are analysed using the principal component analysis (PCA) technique. The eigenvalues of the principal components have been studied for various initial configurations, event fractions containing hot spots in the initial condition and for event centralities with an aim to find it's sensitivity to the initial hot spot configurations.
↳ nucl-thhep-phEPJA(2025)·0 citations
28
Reviving the Affleck-Dine Curvaton Scenario with Compensated Isocurvature Perturbations
Masahiro Kawasaki🇯🇵 · Shunsuke Neda🇯🇵
We revisit the Affleck-Dine curvaton scenario in the framework of supersymmetry, taking Q-ball formation into account. In this scenario, a scalar field carrying baryon number, namely the Affleck-Dine field, generates both the curvature perturbations and the baryon asymmetry of the Universe. However, correlated baryon isocurvature perturbations are inevitably generated, resulting in excessively large correlated matter isocurvature perturbations. We propose a mechanism to suppress them, in which the correlated baryon isocurvature perturbations are canceled by anti-correlated dark matter isocurvature perturbations, thereby realizing compensated isocurvature perturbations. We show that the scenario can simultaneously account for the baryon asymmetry and the observed curvature perturbations of the Universe without generating excessively large matter isocurvature perturbations.
↳ astro-ph.COhep-ph0 citations
29
Impact of Baryon anti-Baryon annihilation on hyperon ( $Λ$ , $Λ ˉ$ ) production and apparent strangeness enhancement in $Λ ˉ / p ˉ$ in heavy ion collisions at SPS energy
Ekata Nandy🇮🇳 · Subhasis Chattopadhyay🇮🇳
A deconfined medium of quarks and gluon, called the Quark-Gluon Plasma (QGP) is produced when heavy-nuclei are collided at relativistic energies. The QGP formation is often characterized by a phenomenon called strangeness enhancement where, the relative production of strange-to-non-strange particles are enhanced in central collisions compared to peripheral or proton-proton interactions. Besides the enhancement in K/ $π$ ratios, a non-monotonic energy dependence was also reported for $Λ ˉ$ to $p ˉ$ ratios at CERN SPS, attributed to a signature for the strangeness enhancement as well. As anti-particles are produced directly from the reaction, the $Λ ˉ$ / $p ˉ$ ratios are considered as a cleaner probe for the strangeness enhancement. However, at this energy range hadronic interactions have a dominant role to play and, importantly for $Λ ˉ$ and $p ˉ$ , processes like baryon-anti-baryon ( $B B ˉ$ ) annihilation can have a significant impact. In this work, we use a hadronic transport model UrQMD, to investigate the role of baryon-anti-baryon ( $B B ˉ$ ) annihilation on $Λ$ , $Λ ˉ$ hyperon production and its effect on $Λ ˉ$ / $p ˉ$ ratios. The UrQMD calculations that include $B B ˉ$ annihilation can produce the trend of average transverse mass spectra for $Λ$ and $Λ ˉ$ , as well as, the characteristic enhancement in $Λ ˉ$ / $p ˉ$ ratios in data as a function of centrality and collision energy. Furthermore, $Λ ˉ$ / $p ˉ$ ratios extracted from the feed-down corrected SPS data are seen to be in good agreement with UrQMD model calculations with $B B ˉ$ annihilation. This suggests that $Λ ˉ$ / $p ˉ$ enhancement is not necessarily because of strangeness enhancement and $B B ˉ$ annihilation has a significant role to play.
↳ nucl-thhep-phEPJA(2022)·2 citations
30
Intrinsic coupling between transverse spherocity and elliptic flow in heavy-ion collisions
Subikash Choudhury🇮🇳 · Ekata Nandy🇮🇳
Transverse spherocity ( $S_{0}$ ) is an event-shape observable widely used to classify collision events according to their topology, particularly to distinguish jet-like from isotropic events. Low-spherocity events are generally interpreted as being associated with enhanced jet activity. This event classification has also been applied to heavy-ion collisions to investigate the influence of event topology on several observables, including elliptic flow and constituent-quark-number scaling. In this work, we demonstrate that such an interpretation requires careful reconsideration. Using toy Monte Carlo simulations, A Multiphase Transport (AMPT) model calculations, and an analytical formulation of the spherocity observable, we show that transverse spherocity is intrinsically related to the elliptic flow coefficient, $v_{2}$ . This connection arises because the axis that minimizes the spherocity aligns with the event symmetry plane, causing events with larger elliptic anisotropy to naturally exhibit smaller spherocity values even in the absence of genuine jet-like topologies. We further show that this intrinsic relation gives rise to an inherent anti-correlation between transverse spherocity and $v_{2}$ , implying that several characteristics previously attributed to the enhanced jet-like nature of low-spherocity events in heavy-ion collisions can instead be understood as consequences of collective anisotropic flow. Our results indicate that, in heavy-ion collisions, transverse spherocity should be interpreted primarily as a probe of the collective momentum-space anisotropy rather than as a direct measure of jetty event topology. Consequently, physics conclusions drawn from spherocity-selected events should explicitly account for its intrinsic correlation with elliptic flow.
↳ nucl-thhep-phPRD(2026)·0 citations
31
Spin and momentum fraction carried by partons in the nucleon
Constantia Alexandrou🇨🇾 · Simone Bacchio🇨🇾 · Jacob Finkenrath🇩🇪 · Christos Iona🇨🇾 · Giannis Koutsou🇨🇾 · Christian Kummer🇨🇾 · Yan Li🇨🇾 · Bhavna Prasad🇨🇾 · Gregoris Spanoudes🇨🇾
We determine the momentum fraction and angular momentum carried by quarks and gluons in the proton in lattice QCD. We use four ensembles simulated with up, down, strange and charm quarks with their masses tuned to their physical values. These ensembles have similar physical volume and different lattice spacings allowing us to take the continuum limit directly at the physical pion mass point. We extract the quark and gluon momentum fractions and total angular momentum in the continuum limit as well as the intrinsic quark spin and orbital angular momentum contributions to the proton spin. We find the total momentum fraction $⟨ x_{N} ⟩ = 0.995 (60) (29)$ and the total spin $J_{N} = 0.507 (43) (65)$ , showing that both the momentum and spin sum rules are satisfied. We compare our results to those extracted from phenomenological analyses.
↳ hep-lathep-exhep-phnucl-ex+10 citations
32
Hubble tension: the shape wall
Miguel A. Sabogal🇮🇹 · Luis A. Escamilla🇹🇷 · Davide Pedrotti🇮🇹 · Edvig Selimaj🇮🇹 · Sunny Vagnozzi🇮🇹
The standard "no-go theorem" against late-time solutions to the Hubble tension is essentially a normalization wall, since Baryon Acoustic Oscillation (BAO) measurements constrain the product $H_{0} r_{d}$ , with $r_{d}$ the sound horizon at baryon drag. However, late-time solutions (which keep $r_{d}$ fixed) are tightly constrained not only by the BAO normalization $H_{0} r_{d}$ , but also by the shape of the expansion history, i.e. the dimensionless expansion rate $E (z) \equiv H (z) / H_{0}$ . We show that, if $r_{d}$ and the acoustic angular scale $θ_{s}$ are fixed, an increase in $H_{0}$ needs to be matched by an equal fractional increase in the dimensionless distance integral $I \equiv \int d z / E (z)$ : $δ H_{0} / H_{0} ≃ δ I / I$ . We use this to quantify the "shape wall" set by relative distance constraints on $E (z)$ , which we reconstruct nonparametrically, using Gaussian Processes and the latest unanchored Type Ia Supernovae (SNeIa) and BAO data. In our most conservative analysis using PantheonPlus SNeIa and DESI DR2 BAO data, we find a maximum fractional increase in $H_{0}$ of $≲ 2%$ , falling well short of the $≳ 8%$ required to solve the tension. This shape wall holds even in the presence of early-time new physics, and limits the maximum increase in $H_{0}$ which can be contributed by late-time modifications to $E (z)$ at fixed $θ_{s}$ . Therefore, late-time modifications, whether invoked alone or alongside early-time new physics, face not only the well-known normalization wall, but also a stringent percent-level shape wall.
↳ astro-ph.COgr-qchep-phhep-th3 citations
33
Enhanced hydrodynamic predictions for $v_{02} (p_{T})$
Rupam Samanta🇵🇱 · Tribhuban Parida🇵🇱 · Jean-Yves Ollitrault🇫🇷
We present hydrodynamic predictions for the new observable $v_{02} (p_{T})$ , which measures the correlation of particle spectra with elliptic flow. We implement a data-driven correction so as to match hydrodynamic calculations to elliptic flow ( $v_{2} (p_{T})$ ) data. The corrected results are in fair agreement with $v_{0} (p_{T})$ data up to high $p_{T}$ . We make predictions for $v_{02} (p_{T})$ of unidentified charged hadrons up to $p_{T} = 10$ ~GeV $/ c$ , and of pions, kaons and protons up to $p_{T} = 5 - 6$ ~GeV $/ c$ , in several centrality windows, for Pb+Pb collisions at $s_{N N} = 5.02$ ~TeV. For $p_{T} > 4$ ~GeV $/ c$ , we predict a decrease of $v_{02} (p_{T})$ of charged hadrons in mid-central collisions, and meson-baryon splitting. We also predict a non-monotonic variation of $v_{02} (p_{T})$ for protons at low $p_{T}$ above $30%$ centrality. This is a specific feature of this new observable, which is not observed for the usual flow observables $v_{2} (p_{T})$ and $v_{0} (p_{T})$ .
↳ nucl-thhep-phnucl-ex0 citations
34
Ultra-High-Energy Particle Production in Binary Mergers Endowed with Magnetic Fields
Carlos H. Coimbra-Araujo🇧🇷 · Rita C. Anjos🇧🇷 · Jonas P. Pereira🇧🇷 · Jaziel G. Coelho🇵🇱
We study the production of ultra-high-energy particles via the Bañados--Silk--West (BSW) mechanism in the pre-merger phase of binary systems detected by LIGO-Virgo-KAGRA. By solving the geodesic equations for charged particles in magnetized Kerr spacetime with fields of $B \sim 1 0^{12}$ -- $1 0^{14}$ ~G, we demonstrate that collisions near the horizon can achieve center-of-mass energies $E_{cm} \sim 1 0^{18}$ -- $1 0^{20}$ ~eV, placing them firmly in the ultra-high-energy cosmic-ray (UHECR) range. We systematically explore the parameter space of merger remnants, varying black hole mass ( $M \sim 20$ -- $150 M_{⊙}$ , characteristic of the binary black hole population), dimensionless spin ( $χ_{f} \sim 0.7$ -- $0.9$ ), magnetic field strength, and particle angular momenta. Our analysis reveals three distinct acceleration regimes: a gravity-dominated regime ( $B < 1 0^{12}$ ~G) with negligible magnetic enhancement; a transition regime ( $1 0^{12} G ≲ B ≲ 1 0^{13} G$ ) where gravitational and magnetic effects compete; and a magnetic-dominated regime ( $B > 1 0^{13}$ ~G) where fields amplify collision energies by nearly an order of magnitude. For the 34 gravitational-wave events with high remnant spins ( $χ_{f} > 0.7$ ), we compute the maximum achievable energies, finding that systems with $χ_{f} ≳ 0.85$ and $M ≳ 100 M_{⊙}$ can reach $E_{max} \sim 1 0^{20}$ ~eV. Our results establish magnetized binary mergers, particularly black hole--neutron star systems and postmerger black hole remnants formed in binary neutron star coalescences, as promising sources of UHECRs and provide quantitative predictions linking gravitational-wave observables to particle acceleration efficiency.
↳ astro-ph.HEastro-ph.COgr-qchep-ph+1PRD(2026)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE