HEP Phenomenology·hep-ph

Thu·Jul 9, 2026Thursday·July 9, 2026

32 papers—22 primary·10 cross-listed

01
The Positivity Geometry of Photon--Dark-Photon Effective Field Theories
Sayantan Chakraborty · Yash Dadhwal · Arun M. Thalapillil🇮🇳
We derive positivity bounds on the complete dimension-eight effective field theory of photons and a massless dark photon. The mixed gauge sector contains twelve CP-even Wilson coefficients and an enlarged helicity-amplitude structure. Using a modified forward-limit dispersion relation, we analytically obtain non-trivial linear and non-linear elastic positivity constraints that define a spectrahedral geometry. We analyze implications of these bounds on non-forward amplitudes and discuss where kinetic-mixing and dark-axion-portal UV completions populate this geometry.
hep-phhep-exhep-th0 citations
02
Anomaly Realization in Charge-Flux Detector Correlators
João Barata🇨🇭 · Ratmir Jumanov🇷🇺 · Andrey V. Sadofyev🇪🇸
Quantum anomalies provide a bridge between ultraviolet properties of a theory and its infrared sector. We study how this connection appears in axial-charge-flow observables. In the simplest example, an axial-charge detector probes the fermionic cut of the anomalous triangle and resolves its infrared content as an angular distribution. The massless limit does not commute with the angular integration: a contribution suppressed at fixed angle collapses onto the two beam-collinear directions while retaining the finite integrated sum rule fixed by the axial anomaly. We then replace the axial-charge detector by higher-spin helicity (zilch) detectors and study a family of axial-anomaly-controlled energy-weighted sum rules for the corresponding fluxes. We further show that the same singular localization mechanism and finite zilch-flux sum rules persist in the mixed axial-gravitational channel. We briefly comment on extensions to more general states and multipoint correlators.
hep-phhep-thnucl-th3 citations
03
Phenomenology of Leptophilic Gauge Interactions at Future $e^{+} e^{-}$ Colliders
S. O. Kara🇹🇷
We present an observable-driven study of leptophilic gauge interactions mediated by a neutral vector boson $Z_{ℓ}$ at future $e^{+} e^{-}$ colliders. Focusing on the process $e^{+} e^{-} \to μ^{+} μ^{-}$ , we investigate the sensitivity of angular observables to off-shell leptophilic interactions in regimes where interference effects dominate over resonant rate enhancements. The analysis is centered on the forward-backward asymmetry, which provides a robust probe of interference-induced angular deformations and retains sensitivity well beyond the resonance region. To characterize the relative angular response independently of the overall rate modification, we additionally introduce the interference-normalized quantity $I_{FB}$ as a diagnostic observable. Realistic collider effects, including initial-state radiation, beamstrahlung, and finite energy resolution, are consistently incorporated. Using benchmark configurations for FCC-ee, CEPC, ILC, and CLIC, we derive projected sensitivities in the $(M_{Z_{ℓ}}, g_{ℓ})$ plane. The results demonstrate the complementarity between high-luminosity circular colliders and high-energy linear colliders, reflecting the interplay between precision measurements and the energy enhancement of interference effects. Overall, the present framework provides an experimentally grounded approach for probing leptophilic gauge interactions through interference-sensitive angular observables at future lepton colliders.
hep-phPRD(2026)·0 citations
04
Natural Phantom Dark Energy from a $Z_{N}$ --Axion
Cédric Delaunay🇫🇷 · Admir Greljo🇨🇭
We present a technically natural microscopic realization of apparent phantom dark energy based on an axion coupled to $N$ copies of two-flavor dark QCD related by a $Z_{N}$ exchange symmetry. The symmetry exponentially suppresses the axion vacuum potential, naturally generating the dark-energy scale, while reheating into a single dark sector induces a controlled breaking of $Z_{N}$ that simultaneously restores the physical axion periodicity, sets the dark-matter abundance, and drives the late-time dark-energy dynamics. The selected sector contains dark-pion dark matter, whose finite density initially traps the axion away from its vacuum minimum. As the Universe expands and the dark-pion density redshifts away, the axion is released and rolls on the reheating-induced vacuum potential, generating an effective phantom crossing without tuned cancellations. We identify a viable parameter region that simultaneously reproduces the observed dark-matter relic abundance and dark-energy scale, satisfies cosmological and astrophysical constraints, and qualitatively reproduces the DESI preference for an evolving dark-energy equation of state.
hep-phastro-ph.CO3 citations
05
Particle Cosmology: 1980-2000
Edward W. Kolb🇺🇸
A new field, \emph{Particle Cosmology}, emerged at the interface of elementary particle physics and cosmology in the last two decades of the 20th century. In this chapter of the \emph{Proceedings of the 4th International Symposium on the History of Particle Physics, the Standard Model and Beyond} I will review the development of Particle Cosmology in the period 1980-2000 centered on two events: a conference, \emph{Inner-Space/Outer-Space} held at Fermilab in May 1984 \cite{kolb1986innerspace} and the 1994 Snowmass Summer Study \emph{Particle and Nuclear Astrophysics in the Next Millennium} \cite{kolb1995particle}.
hep-phastro-ph.COhep-th0 citations
06
Collins effect in pion-in-jet production in polarized $pp$ and $e p$ collisions
Carlo Flore🇮🇹 · Umberto D'Alesio🇮🇹 · Marco Zaccheddu🇺🇸
We study Collins azimuthal asymmetries for pion-in-jet production in polarized proton-proton and lepton-proton collisions. We adopt a hybrid transverse momentum dependent approach, with a collinear configuration for the initial state, and employ the transversity and Collins fragmentation functions extracted from semi-inclusive deep inelastic scattering and $e^{+} e^{-}$ annihilation data. After recalling the good description of the STAR data in $pp$ collisions, which supports the universality of the Collins function, we present predictions for Electron-Ion Collider kinematics, both at leading order and by including the quasireal photon exchange in the Weizsäcker-Williams approximation. This contribution is sizable but does not spoil the dominance of quark-initiated channels. This implies that $ℓ p$ processes allow for a clearer access to the transversity distribution, including its sea-quark component.
hep-phhep-exnucl-th0 citations
07
Probing Quasi-Dirac Neutrino Oscillations at Long Baseline Experiments
Noor-Ines Boudjema🇬🇧 · Frank F. Deppisch🇬🇧 · Suka Sriyansu Pattanaik🇮🇳
The Dirac or Majorana nature of neutrinos remains one of the most fundamental open problems in particle physics. A natural intermediate scenario arises when small lepton-number-violating Majorana mass terms break the exact Dirac symmetry. These cause mass eigenstates to form nearly degenerate pairs, each separated by a small mass splitting. We study this quasi-Dirac scenario within a five-neutrino framework, extending the Standard Model by two right-handed neutrinos, which form a nearly degenerate sterile pair alongside the three active states. This extended mixing structure introduces additional phenomenological parameters, including new mixing angles, mass splittings, and CP phases. We use appearance and disappearance data from NO $ν$ A and T2K to constrain the active-sterile mixing angles $θ_{s a}$ and the mass splitting within the sterile pair $Δ m_{54}^{2}$ and forecast the sensitivity achievable at DUNE. We analyse how these parameters modify CP-violating observables relative to the standard three-neutrino case, comparing predicted event rates across both mass orderings and as a function of $δ_{C P}$ .
hep-ph0 citations
08
First constraint on Born-rule violations at high-energy colliders
Antony Valentini🇬🇧 · Mira Varma🇺🇸
We obtain an experimental constraint on possible Born-rule violations at high-energy colliders. We model Born-rule violations with differential scattering cross sections $d σ / d Ω$ subject to an angular smearing by a narrow Gaussian of width $ε$ (with respect to $x = cos θ$ for scattering angle $θ$ ). For large-angle Bhabha ( $e^{+} e^{-} \to e^{+} e^{-}$ ) scattering, at a centre-of-mass energy $s = 29 GeV$ , data from the PEP collider at SLAC allow us to set an upper bound of $ε < 0.042$ at $95%$ confidence. This corresponds to a Gaussian smearing over an angular range of twice the experimental bin width, and hence provides a physically meaningful limit on deviations from the Born rule. Future prospects for improving this limit are discussed.
hep-phhep-thquant-ph0 citations
09
From inflation to hot big bang -- a tutorial on cosmological perturbations
Mikko Laine🇨🇭 · Simona Procacci🇨🇭
These lecture notes are meant as a pedagogic guide to cosmological inflation and the early epochs thereafter. Inflation explains how the seeds for density perturbations, which evolved into the largest structures in our universe, could have formed during a period of exponential expansion. Apart from density perturbations, also tensor perturbations are generated, which may be observed as gravitational waves. The formalism is developed through explicit computations, paying attention to general-relativistic gauge invariance, and to thermalization (the mechanism that converts part of the energy density driving exponential expansion into the conventional hot big bang). For the steps best handled numerically or computer-algebraically, simple python scripts are provided. We aim at an unassuming style, hopefully accessible to students of theoretical high-energy physics.
hep-phastro-ph.COLect.Notes Phys.(2026)·0 citations
10
Perturbative determination of CP phase in CKM matrix using rephasing invariants of hierarchical mass matrices and their inverses
Masaki J. S. Yang🇯🇵
In this paper, we derive approximate expressions for the CP phase $δ$ in the CKM matrix by a perturbative singular value decomposition for hierarchical quark mass matrices $m_{q}$ . The diagonalization is achieved through a seesaw-like procedure in which the heavier generations are successively integrated out, naturally leading to mixing matrices expressed in terms of the mass matrix and its inverse $m_{q}^{- 1}$ . As a result, in the basis where the up-type quark mass matrix is diagonal, $δ$ is reduced to the fourth-order invariant $δ ≃ ar g [- m_{d 12}^{- 1} m_{d 23} / m_{d 11}^{- 1} m_{d 13}]$ , constructed from the down-type mass matrix and its inverse. Furthermore, in the Kobayashi--Maskawa parametrization, the CP phase is likewise expressed in the same basis as the invariant $δ_{KM} ≃ ar g [m_{d 13}^{- 1} m_{d 33} / m_{d 11}^{- 1} m_{d 13}] ≃ π /2$ .
hep-ph0 citations
11
Higgs boson mass and thermal wino dark matter from Starobinsky supergravity with the MSSM
Daniel Frolovsky🇳🇱 · Alexander Belyaev🇬🇧 · Sergei V. Ketov🇷🇺
We propose a framework connecting cosmic microwave background (CMB) observables with high-energy particle phenomenology, based on Starobinsky supergravity coupled to the Minimal Supersymmetric Standard Model (MSSM). Cosmic inflation and supersymmetry (SUSY) breaking occur within the hidden sector emerging from Starobinsky supergravity. The inflationary scale sets the hidden-sector mass scale and, via gravitational mediation of SUSY breaking, the MSSM soft terms. The same hidden sector can also dynamically generate a high-scale $μ$ term. The resulting MSSM spectrum fixes the high-scale threshold corrections and the boundary conditions for the renormalisation-group (RG) evolution of the Higgs quartic coupling. Three-loop RG evolution of the Higgs quartic coupling gives a Higgs boson mass consistent with the measured value within the theoretical and experimental uncertainties, thereby linking the amplitude of primordial scalar perturbations to the Higgs boson mass. With conserved R-parity, the lightest supersymmetric particle is stable, and the minimal framework developed here points to a nearly pure neutral wino as the dark-matter (DM) candidate. In the thermal-relic scenario, the observed abundance selects a wino mass of about $3$ TeV. Recent gamma-ray analyses exclude it as the sole DM component, even for conservative cored Galactic profiles. Alternatives include a subdominant wino fraction or late entropy dilution. Its loop-induced spin-independent wino-nucleon scattering cross section lies below current LUX-ZEPLIN sensitivity but within reach of next-generation liquid-xenon detectors. Electroweak corrections generate a small charged-neutral wino mass splitting, producing a long-lived charged wino and disappearing-track signature. A future $100$ TeV proton collider can discover the corresponding pure-wino signal or exclude the scenario independently of its cosmological abundance.
hep-phastro-ph.COgr-qchep-th0 citations
12
Inclusive Charmless Non-Leptonic B Decays at NLO within and beyond the Standard Model
Stefan Meiser🇪🇸 · Pol Morell🇪🇸 · Angel Picazo🇪🇸 · Javier Virto🇪🇸
We calculate the full set of BSM contributions to the inclusive non-leptonic $B$ -meson lifetime from charmless final states within the framework of the Weak Effective Theory up to next-to-leading order in QCD and to leading power in the heavy-quark expansion. We do so by computing cut diagrams and the corresponding phase space integrals. This involves calculating current-current, penguin-penguin, penguin-dipole and dipole-dipole diagrams with two-, three- and four-particle cuts. We describe the technical difficulties of the computation. We then discuss how our results can be used to constrain new physics scenarios related to the anomalies observed in semi-leptonic and charmless non-leptonic decays.
hep-phhep-exhep-lat0 citations
13
Algebraic Structure of Three-Flavor Neutrino Oscillations in Constant-Density Matter: Cayley--Hamilton Evolution, DMP Resummation, and Closed-Form Uncertainty Propagation
Aaryan Chaulagain🇳🇵 · Anju Dhakal🇳🇵 · Daya Nidhi Chhatkuli🇳🇵
For three-flavor neutrino oscillations in constant-density matter, the Cayley--Hamilton theorem forces the evolution operator into a quadratic polynomial in $H^$ , with coefficients determined by the three real eigenvalues through a Vandermonde system we write out explicitly. The eigenvalues follow from Cardano's trigonometric formula, recovering the Zaglauer--Schwarzer expressions. The Denton--Minakata--Parke (DMP) approximation achieves fractional accuracy better than $1 0^{- 4}$ because its $1$ -- $3$ rotation is a resummation: it removes the near-degeneracy that makes the naive expansion diverge at $A^\to 1$ , replacing the unbounded $(1 - A^)^{- 1}$ with an effective parameter $ϵ_{0} ≲ 0.015$ bounded uniformly in energy. A density-matrix treatment with a Lindblad term handles open-system decoherence and wave-packet effects in the same language; matter-dressed coherence lengths satisfy $L / L_{coh}^{ij} \sim 1 0^{- 3}$ -- $1 0^{- 2}$ for terrestrial baselines. The CP asymmetry $A_{CP} (ν_{μ} \to ν_{e})$ is split into genuine and matter-induced fake contributions. Closed-form Jacobians in the NuFIT~6.0 parameter basis feed Monte Carlo and linearized uncertainty-propagation schemes, the latter validated against a Feldman--Cousins profile-likelihood mapping near physical boundaries. The Denton--Parke NuFast-LBL algorithm [Phys.\ Rev.\ D {\bf 110}, 073005 (2024)] remains the tool of choice for production fits; the analytic expressions here supply what iterative solvers cannot -- parameter continuity, transparent limits, and Jacobians in closed form.
hep-phhep-th0 citations
14
Reappraisal of the Constraints on Heavy Axion-like Particles from Gamma-Ray Bursts
Christopher V. Cappiello🇺🇸 · Saurav Das🇺🇸 · P. S. Bhupal Dev🇺🇸 · Takuya Okawa🇮🇹 · Soebur Razzaque🇿🇦
We reassess existing limits and derive new constraints on heavy axion-like particle (ALP) coupling to photons using gamma-ray bursts (GRBs). ALPs can be produced in the hot dense fireball plasma during the initial stage of GRB outflow, thus potentially disrupting the primary fireball and altering the GRB luminosity. We consider the ALP production rate for various GRB parameters in two different energy injection scenarios of GRB fireball formation, and point out that ALP production is less efficient than previously assumed unless a GRB event is exceptionally energetic. We update the existing energy loss bounds using more realistic GRB parameters. We also point out that in the region of parameter space previously constrained by GRB luminosity criterion, ALP production turns out to be still efficient enough to form a secondary fireball via ALP decay to two photons and their subsequent annihilation to electron-positron pair. This secondary fireball reprocesses the gamma-rays from heavy ALP decay into $X$ -rays, emitted isotropically from its surface, thus allowing us to probe $O (100 MeV)$ -scale ALPs indirectly using $X$ -ray (or future MeV gamma-ray) telescopes, not necessarily directed toward the GRB jet itself. We show that the future point-source sensitivity of $X$ -ray and MeV gamma-ray telescopes may allow us to constrain new ALP parameter space.
hep-phastro-ph.COastro-ph.HE0 citations
15
Gravitational form factors of the pion in light-front holographic QCD
Jiali Deng🇨🇳 · Xiaolong Wang🇨🇳 · Yang Zhou🇨🇳 · Defu Hou🇨🇳
Understanding the internal structure of the pion-particularly the energy-momentum distributions of quarks and gluons and the internal mechanical properties encoded in its gravitational form factors-is a fundamental challenge in quantum chromodynamics (QCD). In this work, we study the gravitational form factors using light-front QCD (LFQCD), combined with the holographic QCD. Our main innovation is the introduction of an effective light-front wave function, with its five-dimensional component obtained from holographic QCD, which is then employed, within the light-front QCD framework, to calculate the pion's gravitational form factors $A (Q^{2})$ and $D (Q^{2})$ as well as its radius. Our computed pion gravitational form factors show good agreement with lattice QCD results, providing nontrivial support for the viability of our phenomenological model.
hep-ph2 citations
16
Neutrino cuboid for normal mass ordering and tribimaximal flavor mixing
Zhi-zhong Xing🇨🇳
Given the latest JUNO implication for normal neutrino mass ordering, we parametrize three neutrino masses in a flavor cuboid: $m_{1} = m_{0} sin ξ$ , $m_{2} = m_{0} cos ξ sin ζ$ and $m_{3} = m_{0} cos ξ cos ζ$ . We find that this cuboid is able to accommodate both neutrino mass degeneracy and tribimaximal flavor mixing in its cubic limit with $ξ_{*} = arctan (1/ 2) ≃ 35.2 6^{\circ}$ and $ζ_{*} = 4 5^{\circ}$ . Assuming $θ_{12} = ξ$ and $θ_{23} = ζ$ for the two large angles of neutrino oscillations and expanding them around $ξ_{*}$ and $ζ_{*}$ , we propose a viable ansatz which predicts a normal but nearly degenerate neutrino mass spectrum and a nearly tribimaximal neutrino mixing pattern. Testing the achieved correlation among $ξ_{*} - θ_{12}$ , $ζ_{*} - θ_{23}$ and $Δ m_{21}^{2} /Δ m_{31}^{2}$ will provide a smoking gun for the validity of this ansatz.
hep-ph1 citation
17
Double quarkonium production in hadronic collisions at fixed-target experiments
Carlo Flore🇮🇹 · Cristian Pisano🇮🇹
We present new results for double quarkonium production in (un)polarized hadronic collisions at fixed-target experiments. Our approach incorporates the transverse momentum dependent factorization in combination with the Color-Singlet Model. We present new analytical expressions for the angular structure of the cross section for the $q q ˉ$ -induced channel, and provide predictions for the unpolarized cross section and transverse single-spin asymmetries for present and future fixed-target experiments at CERN and the LHC.
hep-phhep-exnucl-th0 citations
18
Fierz-complete four-quark interactions and the QCD phase diagram
Zi-ning Wang🇨🇳 · Li-jun Zhou🇨🇳 · Chuang Huang🇩🇪 · Rui Wen🇨🇳 · Shi Yin🇩🇪 · Wei-jie Fu🇨🇳
The dynamics of Fierz-complete four-quark interactions and its influence on the QCD phase diagram have been investigated within the functional renormalization group approach to QCD at finite temperature and densities. It is found that in the vacuum the pion and sigma channels play the overwhelmingly dominant role, and all the other channels are negligible. However, when it is near the critical end point (CEP), the magnitude of four-quark couplings in other channels increases sizably and they become more and more important. In comparison to the single scalar-pseudoscalar channel of four-quark interactions, the dynamics of Fierz-complete four-quark interactions increases a bit the curvature of the phase boundary, and moves the CEP to location of larger baryon chemical potential and smaller temperature.
hep-phnucl-exnucl-th3 citations
19
Dark Neutrons as Dark Matter: Collisions in Halos and Direct Detection from Dark CP Violation
Pablo Figueroa🇪🇸 · Camilo García-Cely🇪🇸 · Giacomo Landini🇮🇹
We consider confining gauge theories with a non-vanishing topological angle $θ$ , which induces CP-violating interactions among dark pions and dark baryons, with dark matter consisting of dark neutrons. The $θ$ term generates scalar pion--baryon couplings analogous to the CP-violating pion--nucleon interactions of QCD. These interactions give rise to an attractive long-range Yukawa potential mediated by the dark pions, whose strength is proportional to $θ$ . Since the dark pions are naturally light pseudo-Goldstone bosons, the resulting force can lead to sizable dark matter self-interactions, providing a simple and theoretically motivated realization of the self-interacting dark matter paradigm. We also investigate the implications for direct detection in scenarios where the dark sector communicates with the Standard Model through a dark photon portal. The $θ$ term induces dark electric dipole moments proportional to $θ$ , which couple directly to the electric fields of nuclei and can substantially enhance direct detection rates. We show how the underlying interactions shape the recoil spectra and discuss the possibility of identifying the CP-violating origin of the signal through its time dependence. Finally, we analyze the interplay between dark matter self-interactions and direct detection signals, showing that both are controlled by the same CP-violating parameter. Our results demonstrate that the topological angle $θ$ can play a central role in determining the phenomenology of composite dark matter.
hep-ph0 citations
20
Revisiting cLFV in "T1-2-A" scotogenic models: asymmetries in three-body lepton decays
A. Darricau🇫🇷 · A. M. Teixeira🇫🇷
We consider a well-motivated class of scotogenic models (the "T1-2-A" variant), and carry out a comprehensive reassessment of its prospects regarding charged lepton flavour violating (cLFV) observables. Aiming only at explaining neutrino oscillation data and putting forward a viable dark matter candidate, a thorough exploration of the model's parameter space suggests that one can have sizeable rates for cLFV observables, especially in rare muon transitions. We have further considered the role of parity and time-reversal asymmetries for cLFV 3-body decays, $ℓ_{α}^{+} \to ℓ_{β}^{+} ℓ_{γ}^{+} ℓ_{δ}^{-}$ , which can be potentially studied in association with polarised muon and tau decays. The new set of observables offers further complementarity information on the scotogenic model under consideration, and possible means of testing it.
hep-ph1 citation
21
On the coverage of electroweak-inos within the pMSSM with SModelS -- a comparison with the ATLAS pMSSM study
Leo Constantin🇫🇷
The ATLAS collaboration has recently performed a vast scan of the phenomenological Minimal Supersymmetric Standard Model (pMSSM) with a focus on the electroweak-ino sector, and analysed how their Run 2 searches for electroweak production of supersymmetric (SUSY) particles constrain this dataset. All the SLHA files from the scan as well as the constraints from the eight individual searches considered by ATLAS were made publicly available. We use this material to study how well the ATLAS constraints can be reproduced with SModelS v3.0. Moreover, we explore how the picture changes when also including CMS results, and what can be gained by the statistical combination of analyses. Finally, we discuss the part of parameter space with light electroweak-inos that remains valid despite the stringent LHC limits. Our results underscore the need of a broad, multifaceted approach for maximising sensitivity and closing loopholes in the extensive SUSY parameter space.
hep-ph0 citations
22
Single inclusive hadron and jet production in lepton-hadron scattering
Jian-Wei Qiu🇺🇸 · Kazuhiro Watanabe🇯🇵
We present the first calculation of single inclusive hadron and jet production at large transverse momentum in lepton-hadron scattering in a joint QCD+QED factorization approach. The scattering cross section is factorized into a convolution of infrared-safe hard coefficient functions with universal lepton distribution functions (LDFs) and parton distribution functions (PDFs) of the colliding lepton and hadron, respectively, together with fragmentation functions (FFs) of the observed hadron (or jet). With joint QCD+QED factorization, the DGLAP-type evolution equations for LDFs, PDFs, and FFs necessarily have evolution kernels calculated in both QCD and QED. We derive a default set of LDFs for our calculations and discuss a strategy to extract universal, non-perturbative LDFs from future data. We present our calculations for single inclusive hadron and/or jet production at the energies of Jefferson Lab and the future Electron-Ion Collider.
hep-phhep-exnucl-exnucl-th3 citations
23
Alleviating the Hubble Tension with Smooth Sign-Switching Dark Energy: Full CMB Constraints with DESI and PantheonPlus
Mariam Bouhmadi-López🇪🇸 · Hsu-Wen Chiang🇨🇳 · Beñat Ibarra-Uriondo🇪🇸
Sign-switching dark energy has recently been proposed as a minimal modification of the late-time expansion history aimed at alleviating tensions within the standard cosmological model. In this work, we investigate ECDM, a smooth realisation of this scenario, with the dark energy density gradually transitioning from a negative to a positive value. We develop a consistent formulation of the perturbation equations that remains well behaved even when the dark energy equation-of-state parameter diverges during the transition. We confront the model with a comprehensive set of cosmological observations, including cosmic microwave background measurements from Planck 2018, ACT DR6 and SPT-3G, baryon acoustic oscillation measurements from DESI DR2, Type Ia supernova distances from Pantheon+, and local Hubble constant measurement of SH0ES. The inclusion of perturbations allows us to assess the impact of the model on structure growth and CMB anisotropies, providing a more thorough test of sign-switching dark energy. Our results show that this class of models is fully compatible with current precision cosmological observations while alleviating the Hubble tension and providing a compelling modification of the late-time dynamics of the Universe.
↳ astro-ph.COgr-qchep-phhep-th4 citations
24
Effective Field Theories for Material Media
Angelo Esposito🇮🇹 · Alberto Nicolis🇺🇸 · Riccardo Penco🇺🇸
We review recent progress in understanding certain aspects of condensed matter systems from a high energy theory perspective. We discuss effective field theories that describe collective bulk and localized excitations in a variety of solid and fluid systems. Particular emphasis is placed on the role played by spacetime symmetries and their spontaneous breaking. The resulting Goldstone dynamics can be seen as underlying a wide variety of phenomena. We attempt to bridge the language gap between subfields while underscoring the numerous conceptual similarities.
↳ hep-thcond-mat.otherhep-ph1 citation
25
Classical conformal invariance and superhorizon dynamics in de Sitter
Maria Cristina Fiore🇪🇸 · Andrea F. Sanfilippo🇪🇸
Soft de Sitter Effective Theory is a well-motivated candidate for the correct effective late-time description of equal-time correlation functions in de Sitter space. In this work, we study its application to theories that enjoy classical conformal invariance, using the conformally-coupled $ϕ^{4}$ -theory as a toy model. While quantum effects generate non-trivial late-time dynamics in such models, we argue that it is not described by the standard construction of the effective theory as discussed thus far in the literature. We show that the tree-level matching of the trispectrum onto the effective theory does not fit into the expected power-counting scheme, and we contrast it with the matching of the tree-level bispectrum in the conformally-coupled $ϕ^{3}$ -theory, where it works consistently. We then propose a prescription to identify the leading superhorizon degrees of freedom in such theories, which should serve as the starting point for the construction of their late-time effective description. The interpretation of logarithms of the form $lo g (- k η)$ in this context is briefly discussed.
↳ hep-thastro-ph.COhep-ph1 citation
26
Kaon-deuteron correlation function from an effective field theory approach
Juan Torres-Rincon🇪🇸 · Àngels Ramos🇪🇸
We present a study of femtoscopic correlation functions for $K^{-} d$ and $K^{+} d$ pairs, and compare our results with recent measurements by the ALICE Collaboration in both Pb-Pb and high-multiplicity $pp$ collisions. The kaon-deuteron wave functions are derived from scattering amplitudes using a unitarized chiral effective theory model describing the elementary interactions of $K^{\pm}$ mesons with nucleons. We then evaluate the $K^{\pm} d$ strong scattering amplitudes by solving the Faddeev equations within two distinct frameworks: the Impulse Approximation and the Fixed Center Approximation, which accounts for multiple scatterings. We also incorporate the long-range Coulomb effects between the kaon and the deuteron. We show that the $K^{-} d$ correlation function exhibits large sensitivity to both the size of the emitting source and the relative momentum of the pair, being heavily influenced by rescattering processes. In contrast, the $K^{+} d$ correlation function is dominated by the weakly repulsive $K^{+} N$ interaction, showing deviations from purely Coulombic behavior only at small emission source sizes. Our predictions are in agreement with the ALICE experimental data, and also with the energy-shift and width of the $1 s$ level of the kaonic deuterium preliminary results from the SIDDHARTA 2 Collaboration.
↳ nucl-thhep-phActa Phys.Polon.Supp.(2026)·0 citations
27
Hadronic and partonic composition of QCD matter across the crossover
Artemiy Lysenko🇺🇦 · Mark I. Gorenstein🇺🇦 · Marek Gazdzicki🇵🇱 · Roman Poberezhniuk🇺🇸 · Volodymyr Vovchenko🇺🇸
We construct a simple equation of state of strongly interacting matter at zero chemical potentials that provides a unified description of lattice QCD thermodynamics in terms of hadronic and partonic degrees of freedom. The hadronic phase is described by the quantum van der Waals hadron resonance gas, extended by excluded-volume repulsion between mesons, while the quark-gluon plasma is modeled as an ideal gas of quarks and gluons supplemented with a phenomenological interaction term proportional to $T^{3}$ . The two regimes are connected by a smooth crossover switching function. The three model parameters - the meson hard-core radius, the strength of the partonic interaction term, and the switching temperature - are determined from a fit to lattice QCD results for the trace anomaly. The resulting equation of state reproduces the lattice data on the pressure, entropy density, energy density, and speed of sound in the temperature range $T = 100$ - $500$ MeV. The fit yields a meson hard-core radius $r_{M} ≃ 0.2$ fm, a partonic interaction scale $A ≃ 600$ MeV, and a switching temperature $T_{0} ≃ 216$ MeV, substantially exceeding both the pseudocritical temperature of the QCD chiral crossover and the chemical freeze-out temperature. This finding suggests that the transition from hadronic to partonic degrees of freedom is considerably more gradual than indicated by the chiral pseudocritical temperature alone, with hadronic states remaining an important component of strongly interacting matter up to temperatures of about $250$ MeV, well above the QCD chiral crossover.
↳ nucl-thhep-ph0 citations
28
Weakly supervised machine learning for model-agnostic searches of new phenomena in the $γ$ -ray sky
Michael Krämer🇩🇪 · Silvia Manconi🇫🇷 · Kathrin Nippel🇩🇪
The $γ$ -ray sky, as observed by the Fermi Large Area Telescope, contains a significant number of unassociated sources that may point to new astrophysical populations or more exotic phenomena. Machine-learning methods are widely used for source classification and searches for new physics, but most existing approaches rely on fully supervised training and therefore on explicit signal models. We explore weakly supervised classification as a less model-dependent strategy for analysing $γ$ -ray source spectra. In a background-versus-mixture setup, classifiers are trained on samples with different signal admixtures rather than on fully labelled signal and background events. We study three representative scenarios: pulsar-active galactic nuclei separation as a controlled benchmark, the identification of dark-matter subhalos, and spectral irregularities induced by axion-photon oscillations. In each case we investigate the impact of signal fraction and sample composition on classification performance. Our results show that weak supervision can identify anomalous or signal-like subsets of data while reducing the reliance on detailed signal templates during training. In favourable cases, the method approaches the performance of fully supervised classifiers, while remaining applicable in situations where the signal model is uncertain or only partially specified. Weakly supervised learning therefore provides a complementary candidate-selection and anomaly-ranking strategy for $γ$ -ray data analysis and searches for new phenomena.
↳ astro-ph.HEastro-ph.IMhep-ph0 citations
29
Massive Graviton Dark Matter from a Gapped Continuum
Eugenio Megias🇪🇸 · Miguel Prieto🇪🇸 · Mariano Quiros🇪🇸
We consider the possibility of dark matter in a warped extra-dimensional theory in presence of a linear dilaton background, with a gapped continuum spectrum, in a brane-world cosmological scenario. Firstly, triggered by self-energy radiative corrections, we study the existence of an isolated resonance of massive gravitons, and its realization as a long-lived feebly interacting dark matter candidate, produced by the freeze-in mechanism. This massive graviton is proved to satisfy all theoretical and experimental constraints, in the sub-MeV mass range. We further consider the close relationship between the existence of this component of dark matter and the presence of an inflaton localized on the brane, with a mass around $1 0^{11}$ GeV and a sub-TeV reheating temperature, in a brane inflationary scenario that allows to reproduce the most recent cosmological observables. Secondly, the gapped continuum of gravitons, a particular five dimensional realization of the physics of unparticles, is identified as a holographic fluid which can play the role of holographic dark matter. The production of the holographic fluid goes by an ultra-violet freeze-in mechanism, with an abundance mainly depending on the reheating temperature. Depending on the values of the mass gap and the reheating temperature, one or both components of dark matter can be present.
↳ hep-thastro-ph.COgr-qchep-ph2 citations
30
Hadronic vacuum polarization in hydrogen-like atoms and ions amid the interplay of recoil and finite-size effects
Franziska Hagelstein🇩🇪 · Vadim Lensky🇩🇪 · Bogdan Malaescu🇫🇷 · Vladimir Pascalutsa🇩🇪
Hadronic vacuum polarization (hVP) enters simple atomic systems at a level that is small yet decisive for the precision spectroscopy now underway. We evaluate the hVP contributions to the Lamb shift and the hyperfine splitting (HFS) in ordinary and muonic hydrogen (H and $μ$ H) and hydrogen-like helium-3 ions ( $^{3}$ He $^{+}$ and $μ^{3}$ He $^{+}$ ), using the dispersive data-driven approach and state-of-the-art empirical parametrizations of the $R$ ratio. At the centre of the analysis is the interplay of recoil and finite-size effects: the recoil corrections that dominate the HFS in muonium (Mu), where both constituents are pointlike, are shown to be suppressed by the nuclear elastic form factors (FFs). Our results for the leading hVP contribution to the Lamb shift agree with the literature within uncertainties. Furthermore, we present a first evaluation of the subleading $O (Z^{5} α^{6})$ hVP-finite-size correction, which is by no means negligible in $μ^{3}$ He $^{+}$ . Our results for the hVP contribution to the HFS deviate significantly from all previous evaluations. For the ground-state HFS, we obtain $2.153 (11) μ$ eV in $μ$ H and $- 15.19 (57) μ$ eV in $μ^{3}$ He $^{+}$ , as well as $0.0860 (4)$ kHz and $- 0.476 (17)$ kHz in ordinary H and $^{3}$ He $^{+}$ , respectively. Notably, our result for $μ$ H differs from previous evaluations by roughly ten times the experimental precision anticipated by the upcoming CREMA and FAMU measurements.
↳ physics.atom-phhep-exhep-phnucl-th0 citations
31
Subsolar-mass binary mergers of strange stars and neutron stars: gravitational waves and ejecta
Yong Gao🇩🇪 · Ming-Zhe Han🇩🇪 · Kenta Kiuchi🇩🇪 · Masaru Shibata🇩🇪 · Enping Zhou🇨🇳 · Kenta Hotokezaka🇯🇵
We present the first numerical-relativity simulations of subsolar-mass binary strange star (SS) mergers and compare with binary neutron star (NS) mergers across equations of state, masses, and mass ratios. The self-bound nature of SSs makes them less deformed during the inspiral and keeps a sharp surface up to contact, driving strong shock heating and a large radial bounce that are far weaker in the NS. The more compact SS thus reaches a higher gravitational-wave cutoff frequency $f_{cut}$ before contact but a lower post-merger peak frequency $f_{2}$ . Within each class these frequencies follow quasi-universal relations with the tidal deformability, and their ratio $f_{2} / f_{cut}$ cleanly separates the two classes. Both classes can eject $\sim 1 0^{- 2} M_{⊙}$ of material, neutron-rich for the NS and decompressed quark matter for the SS, a potential source of an electromagnetic counterpart whose observation could test the SS and NS hypotheses for subsolar-mass events.
↳ astro-ph.HEgr-qchep-phnucl-th1 citation
32
Unification of polynomial and exponential cosmological attractors
Renata Kallosh🇺🇸 · Andrei Linde🇺🇸
We introduce a family of simple $α$ -attractor models that can interpolate between exponential and polynomial cosmological attractors. By varying the interpolation parameter $μ$ in these models, one can scan a wide range of values of the spectral index $n_{s}$ matching any combination of CMB and DESI data.
↳ hep-thastro-ph.COgr-qchep-ph3 citations

Affiliations

first authorsco-authorsvia INSPIRE