HEP Phenomenology·hep-ph

Tue·Jul 14, 2026Tuesday·July 14, 2026

54 papers—33 primary·21 cross-listed

01
ACT stands for Awkward Cosmology Theories
Loris Del Grosso🇺🇸 · Alfredo Urbano🇮🇹 · Marcello Ziccolella🇮🇹
Recent observations from the Atacama Cosmology Telescope (ACT) point to a scalar spectral index in tension with the predictions of Starobinsky inflation. Two main strategies have been proposed to reconcile Starobinsky inflation with these data: (i) including higher-curvature operators in the gravitational action, and (ii) modifying the post-inflationary reheating dynamics. We critically re-examine both approaches. When higher-curvature corrections are included, dimensional-analysis arguments allow introducing a second mass scale suppressing higher-dimensional operators, resulting in a one-coupling, two-scale effective theory. We show that fitting the ACT data drives this class of effective theories toward a regime of stronger sensitivity to UV physics, potentially implying fine-tuning of the inflationary observables. We illustrate our general point with two concrete models, namely no-scale supergravity and metric-affine gravity, showing that they provide different realizations of the same underlying $f (R)$ theory. On the reheating side, requiring the CMB modes to re-enter the horizon before recombination leads to stringent constraints on the reheating equation of state, and fitting the ACT data favors an exotic reheating phase with $ω_{reh} > 1/3$ , incompatible with inflaton oscillations about the minimum of the standard Starobinsky potential. Finally, we explore the possibility that a phase of cosmological stasis, driven by a tower of decaying massive states, could play the role of the post-inflationary epoch. We find that accommodating ACT-preferred $n_{s}$ in this setup requires a tower of states with negative energy density. Taken together, our results suggest that reconciling Starobinsky inflation with the ACT data demands ingredients that are challenging to motivate from the perspective of UV-complete theories, undermining the minimality of the original Starobinsky model.
hep-phastro-ph.COgr-qchep-th3 citations
02
Searching for heavy charged relics in the Earth
Reza Ebadi🇺🇸 · Peter W. Graham🇺🇸 · Surjeet Rajendran🇺🇸 · Erwin H. Tanin🇺🇸 · Samuel S. Y. Wong🇺🇸
We propose a method for detecting an ambient density of heavy, electrically-charged particles. Such particles would impact the Earth, lose energy in terrestrial matter, and become trapped. We study the accumulation of these rare particles in multiple target materials that provide large exposure, such as water and geological rocks. We discuss strategies for concentrating the particles by centrifugation or gravitational settling, along with particle identification using mass spectrometry. This method enables the discovery of charged relics with masses $1 - 1 0^{12} TeV$ comprising a tiny fraction of the local dark matter density, reaching down to $f_{X} \sim 1 0^{- 20}$ at the lowest masses. A pathfinder experiment using only a liter of water and one centrifuge (or $\sim m^{3}$ and no centrifuge) operating for a month can already reach $f_{X} \sim 1 0^{- 10}$ and probe new parameter space.
hep-phastro-ph.COhep-ex1 citation
03
Darkly Charged ALPs
Nicolás M. Arenaza🇪🇸 · Enrique Fernández-Martínez🇪🇸 · Belén Gavela🇪🇸 · Elizabeth E. Jenkins🇺🇸 · Aneesh V. Manohar🇺🇸 · Pablo Quílez🇺🇸 · Thomas Steingasser🇪🇸
The established $d = 5$ ALP effective Lagrangian describes the interaction of scalars with approximate shift-symmetry which carry no Standard Model (SM) charges with SM fields. It implicitly assumes that ALPs are not charged under any symmetries of the dark sector. In this paper, we remove this assumption. For ALPs carrying conserved dark charges, no $d = 5$ ALP effective interaction to SM particles is possible. We build the effective Lagrangian for these darkly charged ALPs stemming from a general breaking pattern, and we show that the lowest-order shift-symmetric effective Lagrangian contains just two $d = 6$ operators coupling ALPs to SM particles. We explore the model-independent phenomenological implications of these interactions, as well as the question of whether the dark matter observed in the Universe may consist of darkly charged ALPs. We identify higher order operators of the effective field theory, and determine which types of dark symmetry groups can seed darkly charged ALPs. Illustrative examples of ultraviolet completions which result in darkly charged ALPs at low-energies are provided as well. The darkly-charged ALP scenario can be generalized by including dark gauge interactions. In this paper, we have considered only the case with no such interactions.
hep-phhep-th0 citations
04
Counting b-jets at the FCC-ee as a probe of top-quark flavor physics
Shaouly Bar-Shalom🇮🇱 · Jose Wudka🇺🇸
We explore the sensitivity of a future FCC-ee to multi-TeV new physics (NP) that can generate vector, scalar and tensor flavor-changing (FC) $ee t u_{k}$ contact interactions ( $u_{k} = u, c$ for $k = 1, 2$ ), probed via single top-quark production, $e^{+} e^{-} \to t u ˉ_{k}, t u ˉ_{k} γ$ (+ c.c.) and leading (following the top-quark decay) to two- and four-jet signals, $e^{+} e^{-} \to 2 j + X, 4 j + X$ , where $X$ denotes any non-jet final-state particles. Our analysis exploits an approximately conserved Standard Model (SM) quantum number introduced in [1] and termed " $b$ -Parity" ( $b_{P}$ ), which is applicable to scattering processes of the type $e^{+} e^{-} \to n \cdot j_{b} + m \cdot j_{ℓ} + X$ , where $n$ and $m$ are the number of produced $b$ -jets and light-jets ( $u, d, c, s,$ and/or gluons) and $b_{P} = (- 1)^{n}$ . The FC $ee t u_{k}$ four-fermion interactions can generate distinct $b_{P}$ -odd ( $b_{P} = - 1$ ) signals in these multi-jet events, for which the only significant SM background stems from $b$ -jet misidentification. We demonstrate that the FCC-ee, operating at a $s = 240$ GeV (the $Z H$ run phase) with high luminosity and excellent flavor-tagging performance, is an ideal platform to search for these $b_{P}$ -odd signatures. Indeed, by simply counting the number of final-state $b$ -jets, the FCC-ee can probe NP scales of $Λ \sim 10$ TeV for the new heavy states that generate the vector, scalar and tensor $ee t u$ and/or $ee t c$ interactions. This reach, remarkably about 40 times the assumed FCC-ee center-of-mass energy, improves upon current bounds on some of these four-fermion operators by an order of magnitude and it critically relies on high-purity b-jet tagging.
hep-phhep-exPLB(2026)·0 citations
05
Benchmarking the Nearside Energy-Energy Correlators with Mellin Transform
Yuxun Guo🇺🇸 · Feng Yuan🇺🇸
We investigate nearside energy-energy correlators (EECs) at small angles, explicitly incorporating the QCD scaling behavior in both the perturbative and post-confinement regimes through a Mellin-transform framework. As an illustration, we show that a single parameter, $Λ$ , characterizing the transition scale between the two regimes, provides an excellent description of nearside EECs in $e^{+} e^{-}$ annihilation, including the recent ALEPH analysis as well as earlier measurements across different energies, with next-to-next-to-leading-order accuracy and next-to-next-to-leading-logarithmic resummation.
hep-phhep-ex0 citations
06
The Higgs boson through the lens of electroweak precision data
Yannick Fischer🇩🇪 · Johannes Haller🇩🇪 · Andreas Hoecker🇨🇭 · Roman Kogler🇩🇪 · Finn Labe🇩🇪 · Klaus Mönig🇩🇪 · Dennis Schwarz🇦🇹 · Jörg Stelzer🇺🇸
The global electroweak fit tests the quantum structure of the Standard Model by confronting precision measurements with high-order theoretical predictions. This paper presents an updated Gfitter analysis using the latest experimental inputs, notably the new world average of the $W$ -boson mass, and state-of-the-art theoretical calculations. The fit yields indirect determinations of precision observables, including the $W$ and Higgs-boson masses, the top-quark mass, and the effective leptonic weak mixing angle, confirming the remarkable internal consistency of the Standard Model. The analysis is further extended to the Higgs sector by combining ATLAS and CMS signal-strength measurements with electroweak precision data in the $κ$ framework. The resulting electroweak constraints on the Higgs couplings to vector bosons allow a determination of the total Higgs-boson width with a precision of about 10\% or better within a leading-logarithmic oblique interpretation, and provide bounds on invisible and undetected Higgs-boson branching fractions without using direct searches for invisible Higgs decays. The paper also presents bounds on Wilson coefficients in the Standard Model Effective Field Theory together with projections for the precision of the global electroweak fit achievable at the FCC-ee.
hep-phhep-ex3 citations
07
Strong First-Order Electroweak Phase Transitions and Gravitational Waves in the Normal Two-Higgs-Doublet Model: A Comparative Study of the Four Yukawa Types and Thermal Resummation Schemes
Jin-Hwan Cho🇰🇷 · Dongjoo Kim🇰🇷 · Jinheung Kim🇰🇷 · Soojin Lee🇹🇼 · Jeonghyeon Song🇰🇷
We present a comprehensive global analysis of strong first-order electroweak phase transitions (SFOEWPTs) and their associated stochastic gravitational-wave (GW) backgrounds within the Normal Scenario of the $C P$ -conserving Two-Higgs-Doublet Model (2HDM) with softly broken $Z_{2}$ symmetry, where the lighter $C P$ -even scalar is identified as the observed $125 GeV$ Higgs boson. Across all four Yukawa structures (Type-I, II, X, and Y), we track the finite-temperature vacuum evolution, transition dynamics, and GW signatures. To quantify the theoretical uncertainty associated with thermal resummation, we perform a detailed comparison between the Parwani and Arnold--Espinosa prescriptions. While both schemes find that single-step paths overwhelmingly dominate successful transitions and consistently favor the Higgs alignment limit, the resulting SFOEWPT parameter space exhibits a pronounced scheme dependence. The Arnold-Espinosa prescription severely restricts the viable parameter space (with upper bounds on the heavy-scalar masses below approximately 800 GeV) and introduces an extreme parametric sensitivity that produces fragmented distributions and irregular voids in the heavy-scalar mass planes. In contrast, the more stable Parwani prescription allows heavy-scalar masses below $\sim 1.6 TeV$ . We further identify highly restricted GW parameter regions capable of yielding a four-year LISA signal-to-noise ratio above 10, while demonstrating that the acoustic GW source is generically short-lived, leading to a substantial suppression of the predicted signal amplitude. Our results highlight the strong complementarity between future space-based GW observations and high-energy collider searches in probing the cosmological viability of the 2HDM.
hep-ph1 citation
08
Suppressing Extra-Dimensional Axion Isocurvature Dynamically
Gongjun Choi🇺🇸 · Tony Gherghetta🇺🇸
Extra-dimensional QCD axion is well motivated by string compactifications and enjoys enhanced protection against quality-violating effects. If present during inflation, however, its quantum fluctuations generate isocurvature perturbations that strongly constrain the inflationary scale. We propose a dynamical suppression mechanism in warped five-dimensional models, where a radion-inflaton coupling sets the radion minimum at small inter-brane separation during inflation, temporarily enhancing the effective four-dimensional axion decay constant. After inflation, the radion minimum shifts to larger separation, restoring the standard QCD axion window. In a warped orbifold GUT with Goldberger-Wise stabilization, this mechanism can satisfy CMB isocurvature bounds while allowing substantially higher inflationary scales than in conventional pre-inflationary axion cosmology.
hep-phastro-ph.COhep-th1 citation
09
QED vertex and anomalous magnetic moment in the presence of a magnetic field
Alejandro Ayala🇲🇽 · Enrique Muñoz🇨🇱 · Marcelo Loewe🇨🇱 · Juan Cristobal Rojas🇨🇱 · Norberto Scoccola🇦🇷
We compute the fermion-photon vertex in QED in the presence of a constant and uniform magnetic background up to one-loop order. We show that even at tree-level, the vertex is modified due to the loss of Lorentz invariance induced by the magnetic field, thus breaking into longitudinal and transverse pieces. Moreover, the radiative corrections induce the emergence of a rich tensor structure that includes the anomalous magnetic moments in the transverse, parallel, and mixed transverse/parallel directions. We concentrate on studying one of these anomalous magnetic moment components, the one in the purely transverse direction. We find the selection rules for transitions between a few low-lying Landau levels and show that the amplitudes for transitions from an initial to a final Landau level differ by a sign from the reverse process due to the loss of time reversal invariance induced by the presence of the field. Contrary to the vacuum case, the amplitudes are, in general, complex, and the phase factor can be interpreted in terms of a finite life-time of the decaying state. For the anomalous magnetic moment in the purely transverse direction, transitions between states occupying both the lowest Landau levels are forbidden. Moreover, for the computation of the allowed transitions, we find that it is not necessary to include a photon mass since the magnetic field acts as an infrared regulator.
hep-phhep-th4 citations
10
On the Origins of the Strong CP Problem
Anthony G. Williams🇦🇺
The conventional strong $C P$ problem arises from the tension between an unrestricted physical parameter $θ ˉ$ and the experimental constraint $∣ θ ˉ ∣ ≲ 1 0^{- 10}$ . In the standard formulation, a global topological classification of gauge-field configuration space leads to integer-valued sectors, $θ$ -vacua, and $θ$ as a physical vacuum angle. Alternatively, a physical flavor-singlet pseudoscalar phase may be introduced through the quark mass matrix. The axial anomaly relates these descriptions through the invariant combination $θ ˉ = θ + ar g det M$ . We ask the logically prior question of whether known physical principles or observables require the introduction of an independent physical flavor-singlet $C P$ -violating parameter in QCD. We distinguish consequences of local gauge invariance and causal locality from those requiring additional global assumptions or the introduction of a physical flavor-singlet $C P$ -violating parameter. For constant $θ$ , the topological charge density is a total four-divergence with no local variational response to compactly supported field variations, and a nonzero $θ$ coupling is not required by perturbative renormalization. No established QCD phenomenology requires a physical $θ ˉ$ parameter. Without such a parameter, the topological susceptibility, axial anomaly, 't~Hooft vertex, Leutwyler--Smilga and Witten--Veneziano relations, standard lattice QCD results, semiclassical instanton solutions, and established phenomenological successes of QCD all remain. Nothing prevents the introduction of $θ ˉ$ as an independent physical parameter, which is consistent with these same QCD results. In this sense, establishing that the strong $C P$ problem is an \emph{unavoidable} feature of QCD requires showing why a physical $θ ˉ$ parameter is \emph{required}, rather than merely allowed.
hep-ph4 citations
11
Lorentz-Violating Photon Decay into Neutrinos and Constraints from PeV Photon Stability
Zurab Kepuladze🇬🇪
We study the vacuum decay of a Lorentz-violating photon into a neutrino-antineutrino pair. Lorentz-violating corrections to the photon dispersion relation are parametrized through an effective invariant mass $m_{eff}^{2} = k_{α} k^{α}$ . This makes the otherwise forbidden decay $γ \to ν ν ˉ$ kinematically allowed. The process proceeds through the Standard Model one-loop neutrino electromagnetic vertex and is therefore strongly suppressed. Using the low- $q^{2}$ anapole form factor, we derive the decay rate and apply it to TeV and PeV photons. We find that below the electron-positron threshold the neutrino channel is open but generally too slow to provide stronger constraints than existing bounds. Above the threshold, $γ \to e^{+} e^{-}$ dominates unless the relative photon-electron LIV parameter closes this channel. In that case, the neutrino decay gives an independent constraint on photon-neutrino relative LIV parameters.
hep-phastro-ph.HE0 citations
12
Matter Profile Mismodeling as the Origin of the CP CPT Degeneracy in Long-Baseline Neutrino Oscillation
Bipin Singh Koranga🇮🇳 · Vivek Kumar Nautiyal🇮🇳
We demonstrate that approximating the Earth's density profile with a single path averaged value instead of the spatially resolved Preliminary Reference Earth Model PREM generates a joint parameter degeneracy in the $(δ_{CP}, Δ_{CPT}, θ_{CPT})$ space. At long baselines ( $L \geq 5000 km$ ), this geometric artifact becomes entirely indistinguishable from genuine Beyond the Standard Model (BSM) physics. While previous studies established individual channel biases separately, this work provides the first analytic proof that these biases form an extended two dimensional valley within the full three-parameter space. Furthermore, we rigorously demonstrate that multi channel combinations alone are insufficient to resolve this degeneracy. A Poisson loglikelihood chi square analysis confirms that DUNE like exposures utilizing a constant density approximation would erroneously report this artifact as a $\pm 3 σ$ BSM discovery. Specifically, at $L = 7000 km$ , the constant-density assumption shifts the recovered $δ_{CP}$ by $17. 8^{\circ}$ and fabricates a spurious CPT violation at $Δ_{CPT} = 4.1 \times 1 0^{- 4} eV^{2}$ . Consequently, full spatially resolved PREM propagation is established as a strict mathematical requirement rather than an optional refinement for the correct physical interpretation of data from next-generation long baseline experiments, including DUNE, HyperKamiokande, and P2O.
hep-ph1 citation
13
Quantum corrections as a Bound for Detecting Self-Interacting Ultralight Dark Matter
Jae-Weon Lee🇰🇷 · Chueng-Ryong Ji🇺🇸
We investigate the implications of the interactions between ultralight dark matter (ULDM) and the Standard model particles for the effective self-interaction coupling constants of ULDM. Our analysis shows that one-loop quantum corrections can result in a substantial increase in the effective coupling constant, which is tightly constrained by cosmological observations. Our findings highlight the importance of considering quantum corrections in the detection of ULDM.
hep-phastro-ph.CO0 citations
14
$λ$ , $ρ$ , and $σ$ Regge trajectories for the quadruply heavy pentaquark $bb u ˉ cc$ in the diquark-triquark picture
Xin-Ru Liu🇨🇳 · Qi Liu🇨🇳 · Jiao-Kai Chen🇨🇳
Systematic investigations of four series of Regge trajectories for quadruply heavy pentaquarks are still lacking. Using the diquark and triquark Regge trajectory relations, we propose the Regge trajectory relations for the quadruply heavy pentaquark $bb u ˉ cc$ : $M = 2 m_{b} + 2 m_{c} + m_{u} + 5 C /2 + β_{x_{λ}} (x_{λ} + c_{0 x_{λ}})^{2/3}$ $+ β_{x_{ρ_{1}}} (x_{ρ_{1}} + c_{0 x_{ρ_{1}}})^{2/3} + β_{x_{ρ_{2}}} x_{ρ_{2}} + c_{0 x_{ρ_{2}}} + β_{x_{σ}} (x_{σ} + c_{0 x_{σ}})^{2/3}$ . Four series of Regge trajectories, namely the $λ$ -, $ρ_{1}$ -, $ρ_{2}$ -, and $σ$ -trajectories, are investigated. We demonstrate that accounting for the internal structure and substructure of pentaquarks is indispensable for constructing the $ρ_{1}$ -, $ρ_{2}$ -, and $σ$ -trajectories; without such structural considerations, functional form and trajectory parameters can only be obtained via pure fitting against theoretical or experimental data. We further prove that the Regge trajectories of diquark 1, triquark, and diquark 2 (emdedded within the triquark) do not correspond one-to-one to the $ρ_{1}$ -, $ρ_{2}$ -, and $σ$ -trajectories. Nevertheless, these trajectories govern the behaviors of the respective $ρ_{1}$ -, $ρ_{2}$ -, and $σ$ -trajectories. For both configurations $(bb) (u ˉ (cc))$ and $(cc) (u ˉ (bb))$ , the $λ$ -, $ρ_{1}$ -, and $σ$ -trajectories exhibit behavior of $M \sim x^{2/3}$ ( $x = n_{r_{1}}, n_{r_{3}}, l_{1}, l_{3}, N_{r}, L$ ), whereas the $ρ_{2}$ -trajectories exhibit behavior of $M \sim x$ ( $x = n_{r_{2}}, l_{2}$ ). The functional behavior of Regge trajectories for diquarks and triquark offers guidance for fitting the pentaquark Regge trajectories. Additionally, we provide rough estimates for spin-averaged masses of the $λ$ -, $ρ_{1}$ -, $ρ_{2}$ -, and $σ$ -excited states.
hep-ph0 citations
15
Do primordial quark pellets solve the dark matter puzzle?
Domenec Espriu🇪🇸
We show that primordial quark pellets (PQP), ultra dense quark matter mini-stars formed at around 1 TeV, naturally arise in a radiation dominated universe if rare baryon overdensities are produced by collapsing Peccei-Quinn domain walls or similar superhorizon structures. Solving the Tolman-Oppenheimer-Volkoff equation with a hot quark equation of state, we find stable solutions with a maximum mass of $1 0^{- 2}$ solar masses and radii of approximately 100 meters, although the formation mechanism favours much smaller objects. Once formed, PQPs cool and evolve intro mini neutron stars or stable strange matter nuggets, depending on the QCD ground state. Formation probabilities of $1 0^{- 9}$ to $1 0^{- 4}$ per horizon volume could suffice to reproduce the present dark matter density without altering Big Bang Nucleosynthesis or requiring entropy dilution. PQPs completely evade microlensing constraints if their mass is below $1 0^{- 7}$ solar masses, a range that could easily accommodate most of the dark matter. PQPs thus potentially constitute a conservative, Standard-Model based, and observationally testable solution to the dark matter puzzle.
hep-phastro-ph.COgr-qc2 citations
16
Migdal Ionization as a Probe of Light Dark Matter from Nuclear Transition
Yuanchao Lou🇨🇳 · Liangliang Su🇩🇪 · Lei Wu🇨🇳
Nuclear reactors serve as a key artificial source of light dark matter. Direct detection of reactor-produced dark matter faces substantial obstacles, since quenching effects suppress conventional elastic scattering signals below detector thresholds. We present a new search strategy utilizing the Migdal effect in germanium detectors to probe light dark matter produced via nuclear de-excitation from reactors. Using ON-OFF residual spectra from the TEXONO experiment, we set a new stringent limit on the dark matter and nucleus interaction over the mass range $0.01 MeV \leq m_{χ} ≲ 2.6 MeV$ , which provides a complementary bound to existing cosmological and astrophysical limits.
hep-ph0 citations
17
The KM3NeT 220 PeV event: a neutrino messenger from the grand unification scale?
Vernon Barger🇺🇸
The 220~PeV neutrino KM3-230213A, in tension with IceCube and Auger unless narrow, admits a two-body reading: relic decay $X \to ν ν ˉ$ with $m_{X} \approx 4.4 \times 1 0^{8}$ ~GeV. Consistency with neutrino and $γ$ -ray bounds sets $τ / f \approx 1 0^{29}$ -- $1 0^{30}$ ~s, lifetime over relic fraction. For a flavored $^{1} S_{0}$ onium, the operator scale lands in the Majorana-mass range of unified models: one Higgs insertion gives a singlet mediator, $M /∣ C_{7} ∣^{1/3} \approx 1 0^{14}$ -- $1 0^{16}$ ~GeV across the allowed relic fraction; two give the seesaw window; Dirac or Majorana neutrinos select the branch. We give the construction and its decisive tests.
hep-phastro-ph.HE0 citations
18
A Unified Study of Hidden-Charm and Hidden-Bottom Mesons
Vikas Patel🇮🇳 · Chetan Lodha🇮🇳 · A. K. Rai🇮🇳
We present a unified phenomenological analysis of hidden-charm and hidden-bottom mesons, treating the $c\bar c$ and $b\bar b$ sectors within a common screened-potential and QCD sum-rule framework. The mass spectra are obtained from a screened Coulomb-plus-confining interaction with spin-dependent corrections, while the short-distance decay constants, annihilation widths and electromagnetic transition form factors are organized through two-point and three-point QCD sum rules. The same calculated states are then used to study E1 and M1 radiative transitions, Regge trajectories and finite-spectrum thermodynamic observables constructed from excitation energies relative to the corresponding ground states. The results are discussed together rather than as disconnected outputs: the mass spectra determine the state assignments, the Regge plots test the global level ordering, the radiative widths probe orbital and spin-flip overlap integrals, and the QCD sum-rule quantities connect the spectrum to current-coupled observables. The comparison of the two hidden-flavour sectors shows the expected compression and stronger spin suppression in bottomonium, while charmonium remains more sensitive to fine-structure, radial-node and medium-related effects. The resulting picture provides a coherent vacuum benchmark for $c\bar c$ and $b\bar b$ spectroscopy, radiative transitions and QCD sum-rule observables.
hep-phEPJC(2026)·0 citations
19
The Impossible Triangle: A No-Go for Symmetry-Protected Scalar Portals in Interacting Dark Energy
Mohid Farhan🇵🇰
The $S_{8}$ tension motivates interacting dark energy (IDE), but embedding IDE in UV-complete physics faces severe naturalness challenges. We analyze four symmetry-protected DM--DE portals ( quartic ( $\frac{1}{2} λ ϕ^{2} χ^{2}$ ), trilinear ( $g ϕ χ^{2}$ ), derivative ( $(c_{6} / Λ^{2}) (\partial_{μ} ϕ)^{2} χ^{2}$ ), and fermionic Yukawa ( $y ϕ ψ ˉ ψ$ ) )within a $Z_{2}$ -symmetric Inert Doublet + Singlet Model. The trilinear portal requires $β \sim 0.45$ ( $g \sim 1 0^{- 16} GeV$ ), overshooting the radiative bound $g ≲ 1 0^{- 42} GeV$ by $\sim 26$ orders (tuning $Δ \sim 1 0^{52}$ ). The quartic portal needs $λ \sim O (1 - 10)$ versus $λ ≲ 1 0^{- 86}$ ( $Δ \sim 1 0^{87}$ ). The derivative portal saturates dynamically at $≲ 4%$ suppression. The Yukawa portal yields $Δ \sim 1 0^{52}$ , persisting even with SUSY cancellation. No single-mediator model simultaneously satisfies technical naturalness and resolves the $S_{8}$ tension. Viable solutions require either multi-field tuned cancellations or explicit symmetry breaking with quantified fine-tuning.
hep-ph0 citations
20
Multipole structure of the $N \to Δ$ Transition Generalized Parton Distributions
June-Young Kim🇰🇷 · Hyun-Chul Kim🇰🇷
We establish the multipole structure of the $N \to Δ$ transition at the level of the generalized parton distributions (GPDs). We decompose the four transition GPDs into one monopole, two dipole, and one quadrupole components in the transverse plane by a multipole expansion of the covariant transition matrix element in terms of the three-dimensional spin-transition tensors and the transverse momentum transfer. These multipole components are in one-to-one correspondence with the light-front helicity amplitudes. In the zero-skewness limit, the multipole GPDs define impact-parameter transition densities, which generalize the transverse transition charge densities to the $x$ -dependent level. These transition densities arise from non-diagonal matrix elements between two distinct hadronic states and must therefore be distinguished from the diagonal densities of the nucleon and the $Δ$ . The multipole transition densities visualize the monopole, dipole, and quadrupole structures of the partonic $N \to Δ$ transition in the transverse plane.
hep-phhep-exhep-lat1 citation
21
Conversion-Driven Baryogenesis in Flavored Dark Matter Models
Benedetta Belfatto🇩🇪 · Monika Blanke🇩🇪 · Jan Heisig🇩🇪 · Lena Rathmann🇩🇪 · Felix Wilsch🇩🇪
The dark matter and baryon asymmetry problems remain two of the most pressing questions in fundamental physics. Considering lepton-flavored dark matter, it has recently been shown that the cogenesis of dark matter and the baryon asymmetry can be economically achieved via conversion-driven freeze-out. This mechanism leverages semi-efficient conversions to drive a departure from equilibrium while preserving independence from initial conditions through early thermalization of the dark sector. In this work, we develop this mechanism further, providing a detailed analysis of the chemical-equilibrium conditions and demonstrating that the framework can be extended to quark-philic scenarios, where the matter-antimatter asymmetry is generated resonantly through baryon-number-conserving $C P$ -violating conversions of a mediator field into Standard Model quarks and dark matter. The strong QCD interactions of the colored mediator, including bound-state formation effects during freeze-out, substantially enlarge the viable parameter space and allow dark matter masses from a few hundred GeV up to the TeV scale. We furthermore assess the impact of thermal effects by comparing a minimal treatment with a setup that approximately accounts for thermal masses and their kinematic consequences. The resulting scenario predicts striking long-lived particle signatures with soft displaced decay products that remain only partially explored at the LHC and motivate dedicated searches at the HL-LHC.
hep-ph0 citations
22
Soft photon approximation in a laser field: applications
Peter A. Krachkov🇷🇺 · Simon V. Sorokin🇷🇺
We apply the soft photon approximation to QED processes in a strong plane-wave laser field. New compact expressions for the emission factors are presented, which simplify the generalization to multiple soft photon emission. The method is applied to nonlinear single, double, and $N$ -photon Compton scattering. For single Compton scattering, we show that the soft photon approximation reproduces the exact spectrum with accuracy $O (ω / ε)$ , significantly outperforming the classical radiation theory. For double Compton scattering, we derive analytical expressions for the differential probability in two kinematic regimes: when both photons are soft, and when one photon is soft while the other has arbitrary energy. We present a compact analytical expression for the amplitude of $N$ -photon emission within the soft photon approximation. A numerical implementation in Wolfram Mathematica for single and double Compton scattering is provided.
hep-ph0 citations
23
Neutron tagging of heavy lepton pair production at RHIC and LHC energies
Atacan Fatih Candar🇹🇷 · Mehmet Cem Güçlü🇹🇷
We calculated cross sections for $γ γ \to ℓ^{+} ℓ^{-}$ ( $ℓ = e, μ, τ$ ) production in ultraperipheral gold and lead collisions and compare our results with recent measurements from the STAR, ALICE, ATLAS, and CMS experiments at center of mass energies $s_{N N} = 200$ GeV, $s_{N N} = 2.76$ TeV, and $s_{N N} = 5.02$ TeV. The calculations are performed within lowest order quantum electrodynamics (LO QED) using a Monte Carlo technique for calculating the impact parameter dependent probability, and subsequently combined with neutron emission probabilities associated with Coulomb excitation of the nuclei. These neutron emission scenarios are modeled using a Poisson statistics, allowing the cross sections to be categorized into experimentally relevant neutron classes: 0n0n, 0n1n, 1n1n, 0nXn, XnXn, and inclusive (0n0n+0nXn+XnXn) production. To enable a direct comparison with experiments, fiducial phase space restrictions corresponding to the acceptance of each detector are implemented.
hep-ph0 citations
24
Determination of the Odderon amplitude in elastic cross-sections at high energies from scaling and analyticity
J. A. velazquez Corral🇺🇸 · B. G. Giraud🇫🇷 · R. Peschanski🇫🇷 · C. Royon🇺🇸
Scaling amplitudes describing $pp$ elastic scattering differential cross-sections in the dip-bump region of momentum transfer at the LHC have been recently derived~\cite{scaling}. We check that the same scaling is verified by the $p p ˉ$ cross-section at the highest energy of the Tevatron. Applying the general "energy to phase" relation for a given signature, coming from the analiticity properties inherent to the S-Matrix formalism~\cite{chew}, we derive the scaling amplitude with positive signature (i.e. the Pomeron). Fitting the $pp$ differential cross-sections measured by the TOTEM collaboration leads to some tension with data in the experimental dip observed at moderate momentum transfer. Concentrating the study to the dip/bump region, we are able to determine a contribution of a negative signature amplitude (i.e. the Odderon) leading to a parameter free prediction for the $p p ˉ$ differential cross-section which is in agreement with the D0 data. The extraction of the Odderon amplitude in both modulus and phase is then performed and discussed.
hep-phhep-exnucl-exnucl-th2 citations
25
Coulomb Effects in Momentum-Space Femtoscopy: A Case Study of the $K ˉ Ω$ System
Pablo Encarnación🇪🇸 · Amador García-Lorenzo🇪🇸 · Miguel Albaladejo🇪🇸 · Albert Feijoo🇪🇸 · Juan Nieves🇪🇸 · Isaac Vidaña🇮🇹
We present a momentum-space framework for the consistent treatment of Coulomb interactions in femtoscopic correlation functions based on a modified Vincent--Phatak method that is more amenable to numerical implementation. The formalism provides a practical approach to incorporating Coulomb effects at the short distances relevant for femtoscopy within the Lippmann--Schwinger equation, while preserving a unified treatment of the strong interaction. As an application, we study the $S = - 4$ pseudoscalar--baryon decuplet interaction in the $K ˉ Ω$ system and present predictions for the singly and doubly negatively charged channels, $K ˉ^{0} Ω^{-}$ and $K^{-} Ω^{-}$ . As an additional validation of the formalism, we have also applied it to the well-studied $pp$ system. We further assess the limitations of the asymptotic wave-function approximation and quantify corrections accounting for the short-distance structure of the interaction potential. We introduce a phenomenological parameter that effectively absorbs contributions from both the finite source size and the off-shell structure of the interaction, the latter being one of the main obstacles to extracting detailed information on hadron--hadron interactions from femtoscopic measurements in a model-independent way.
hep-phnucl-th2 citations
26
Unitarization Schemes for High-Energy Elastic Scattering
E. G. S. Luna🇧🇷
We examine key features of the eikonal and $U$ -matrix unitarization schemes and apply both frameworks to investigate the high-energy behavior of the elastic scattering amplitude, considering input amplitudes whose asymptotic behavior is driven exclusively by Pomeron exchange. Particular attention is devoted to assessing how the extracted Pomeron parameters depend on the assumed trajectory form. In this context, we compare linear and nonlinear Pomeron trajectories, evaluating their impact on the phenomenological description of the data and on the stability of the fitted parameters.
hep-phhep-ex0 citations
27
An improved moment QCD sum rule
Jin-Peng Zhang🇨🇳 · Xu-Liang Chen🇨🇳 · Wei Chen🇨🇳
QCD sum rules are among the most important non-perturbative tools in hadron physics, with the Laplace sum rule (LSR) and moment sum rule (MSR) being the two most commonly used formulations. Despite their widespread application, both approaches have significant shortcomings: the LSR relies on subjective criteria -- namely OPE convergence and pole dominance -- to constrain the parameter space, while the conventional MSR cannot extract the coupling constant of the interpolating current. More critically, the ground-state masses obtained from these two methods are often inconsistent. In this work, we propose an improved moment sum rule (IMSR) framework that resolves these issues simultaneously. Our method explicitly incorporates quark-hadron duality, which introduces the approximation condition on the OPE side and provides a natural a posteriori constraint on the parameters. We impose rigorous dependence conditions on the unphysical parameters $(Q_{0}^{2}, n)$ to quantify and control their influence. As a result, our framework uniquely determines both the optimal value of the duality parameter and the ground-state mass, without invoking any ad hoc or subjective criteria. It also allows for the simultaneous extraction of the current coupling. Applying the IMSR to a pseudoscalar $u d \Bar d \Bar s$ tetraquark system, the results are in excellent agreement with our previous LSR analyses, validating the effectiveness of the proposed scheme. The IMSR method substantially enhances the robustness and reliability of QCD sum rules, effectively eliminating the subjectivity that has long plagued conventional formulations.
hep-phhep-ex0 citations
28
TRSMScans
Tania Robens🇭🇷 · Roxana Rodriguez🇺🇸 · Manuel Samaniego🇺🇸 · Jason Veatch🇺🇸
In this work, we propose a new scan tool that automatically calculates maximal cross section predictions for a new physics scenario with additional scalar states. While the tool is currently optimized for asymmetric production and decay processes in the form of p p -> h3 -> h1 h2, where hi denote CP even neutral scalars, in principle it can be extended to include any production and decay mode. As the code builds largely on the structure of the publicly available code ScannerS, it can in principle be extended to any other model contained within this tool. We here show first applications for a specific model, the Two-Real-Singlet Model (TRSM), and compare to publicly available results from the LHC collaborations from the previous runs. We also in detail discuss the structure of the code, including code installation, usage, as well as underlying algorithms.
hep-ph2 citations
29
Linearity, Nonlinearity and Universality of Regge Trajectories in Light Mesons: a Statistical Approach
S.S. Afonin🇷🇺
The masses of light non-strange mesons can be parameterized as a function of the radial quantum number $n$ and the orbital angular momentum $L$ . We perform a comprehensive statistical and phenomenological comparative analysis of competing Regge-like formulas evaluated against two experimental datasets: a benchmark sample of 27 well-established states from the 2024 Particle Data Group (PDG) data, and an expanded sample of 85 states compiled within a recently proposed $(L, n)$ -classification. Two linear Regge models for $M^{2} (L, n)$ are tested: one featuring distinct slopes for $L$ and $n$ , $M^{2} (L, n) \propto an + b L$ (Model 1), and another assuming a universal slope, $M^{2} (L, n) \propto a (n + L)$ (Model 2). Model selection is conducted quantitatively using the Residual Sum of Squares (RSS), the adjusted RSS, the Akaike Information Criterion (AIC), and the Bayesian Information Criterion (BIC). Within the 27 benchmark states, Model 2 is statistically disfavored. We argue, however, that this discrepancy is driven by the specific behavior of $S$ -wave ( $L = 0$ ) states. Upon their exclusion, the difference in performance between the two models becomes statistically insignificant, with information criteria selecting Model 2 as the more parsimonious description. Furthermore, we demonstrate that the masses of $S$ -wave states can be successfully accommodated by a physically motivated, nonlinear $L$ -dependent correction. A parallel analysis of the extended 85-state dataset, where the relative contribution of $S$ -wave states is significantly smaller, reveals that Model 2 is statistically preferred, thereby restoring the Coulomb-like degeneracy in the Regge spectrum under consideration.
hep-phhep-ex1 citation
30
Thermal Dilepton Polarization under Rotation or Magnetic Field in Heavy-ion Collisions
Haowen He🇨🇳 · Bowen Hou🇨🇳 · Xinyang Wang🇨🇳 · Minghua Wei🇨🇳
Dilepton (Virtual photon) polarization is characterized by anisotropic coefficients $λ_{θ}$ , $λ_{ϕ}$ , and $λ_{θ ϕ}$ , which are expected to be influenced by vorticity and magnetic fields. This work investigates thermal dilepton production in a quark-gluon plasma via the quark-antiquark annihilation process $q q ˉ \to γ^{*} \to l^{+} l^{-}$ . Virtual photon polarization can be induced by both the spin polarization of quarks and the anisotropy of their momentum distribution in the medium. By employing the modified quark propagator under an external field, we derive the electromagnetic spectral function in a hot medium. Based on the spin-projection decomposition of the spectral function, the spin density matrix elements of the virtual photon and the anisotropy coefficients for the emitted dileptons are determined. Due to the distinct effects of vorticity and magnetic fields on the quark propagator, the resulting invariant mass spectra of dilepton polarization exhibit characteristic differences. Furthermore, our study reveals the response of dilepton polarization signals to external fields of varying strengths, suggesting dilepton polarization as a complementary and sensitive probe for both vorticity and magnetic fields in relativistic heavy-ion collisions.
hep-ph0 citations
31
Multi-scale improved predictions for $pp \to t t ˉ W^{+} + X$
Nikolaos Dimitrakopoulos🇩🇪 · Malgorzata Worek🇩🇪
We compare standard fixed-order NLO QCD predictions for the full off-shell $pp \to e^{+} ν_{e} μ^{-} ν ˉ_{μ} τ^{+} ν_{τ} b b ˉ (j) + X$ processes in the multi-lepton decay channel with the results obtained using the MiNLO approach. The MiNLO method, now also implemented in the Helac-NLO framework, provides a dynamic determination of the renormalization and factorization scale settings by identifying the most likely branching histories of the additional jets through an inverse $k_{T}$ -clustering algorithm. The inclusion of Sudakov form factors accounts for the large logarithms that arise in the presence of widely separated scales. We perform a dedicated comparison of the two approaches at both the integrated and differential (fiducial) cross-section levels for the LHC Run II energy of $s = 13$ TeV. Finally, we present the merging of the full off-shell predictions for $pp \to e^{+} ν_{e} μ^{-} ν ˉ_{μ} τ^{+} ν_{τ} b b ˉ + X$ , $pp \to e^{+} ν_{e} μ^{-} ν ˉ_{μ} τ^{+} ν_{τ} b b ˉ j + X$ and $pp \to e^{+} ν_{e} μ^{-} ν ˉ_{μ} τ^{+} ν_{τ} b b ˉ j j$ , with the aim of improving the description of the underlying $pp \to e^{+} ν_{e} μ^{-} ν ˉ_{μ} τ^{+} ν_{τ} b b ˉ + X$ process.
hep-phhep-ex1 citation
32
Antenna subtraction at NNLO for heavy quark pair production at hadron colliders: the non-diagonal channels
Aude Gehrmann-De Ridder🇨🇭 · João Pires🇵🇹
We present the calculation involving the $q q$ , $q q^{'}$ and $q g$ partonic channels contributing to heavy-quark pair production at hadron colliders through next-to-next-to-leading order in QCD using the antenna subtraction formalism. The calculation is performed in full colour and implemented within the NNLOJET framework. Building upon previously available results, we complete the NNLO treatment of the $q q$ and $q q^{'}$ channels by deriving the integrated subtraction contributions required at the real virtual and double-virtual levels. We further present for the first time the NNLO antenna subtraction terms related to the $q g$ -channel in full colour. The calculation requires several new ingredients, including massive soft factors and convolutions involving integrated massive antennae thereby extending the integrated antenna library to cope with processes with massive fermions. We validate the calculation through analytic infrared pole cancellation and numerical comparisons with existing results. These results complete the NNLO description of the $q q$ , $q q^{'}$ , and $q g$ channels and constitute an important step towards a fully differential NNLO treatment of heavy-quark pair production within the antenna subtraction formalism.
hep-ph0 citations
33
A Standard Model analysis of $D^{0} \to π^{-} π^{+}, K^{-} K^{+}, K_{S}^{0} K_{S}^{0}$
Robert Fleischer🇳🇱 · Maria Laura Piscopo🇨🇭 · K. Keri Vos🇳🇱 · B. Yağmur Zubaroğlu🇳🇱
We investigate the Standard Model (SM) description of the singly Cabibbo-suppressed charm decays $D^{0} \to π^{-} π^{+}$ , $D^{0} \to K^{-} K^{+}$ and $D^{0} \to K_{S}^{0} K_{S}^{0}$ . Using factorisation together with isospin symmetry, we constrain non-factorisable effects and the associated $U$ -spin breaking required by the measured branching fractions. We find that corrections of order $50%$ are sufficient to describe all modes, which although sizeable, are not unexpected for hadronic charm decays. Using the constraints from the branching fractions, we derive SM predictions for the direct CP asymmetry in $D^{0} \to K_{S}^{0} K_{S}^{0}$ , finding it to be at most at the per-mille level in our benchmark scenario, providing motivation for future precision measurements.
hep-ph0 citations
34
Hardware-efficient quantum simulation of intense-field QED
Zhuoyi Li🇨🇳 · Bin Xu🇨🇳 · Zhongtian Dong🇺🇸 · Yuxiang Huang🇨🇳 · Ying-Ying Li🇨🇳 · Yiheng Lin🇨🇳 · Jing Shu🇨🇳
Strong electromagnetic backgrounds make quantum electrodynamics a real-time nonperturbative problem involving dressed fermions and dynamical photons. We propose a trapped-ion protocol for simulating intense-field QED in $3 + 1$ dimensions in the Furry picture. The construction encodes photon modes in collective phonons and Volkov-dressed fermion modes in ion spins, combining native spin-phonon couplings with Clifford circuits that compress nonlocal Jordan--Wigner strings. For nonlinear Breit--Wheeler pair production, the protocol has polynomial resource scaling and is benchmarked against exact single-mode dynamics with controlled Trotter errors. With experimentally motivated phonon heating and dephasing, zero-noise extrapolation substantially reduces deviations in photon-survival and pair-production signals. These results provide a hardware-efficient route to intense-field particle-production dynamics beyond perturbative or static-field descriptions.
↳ quant-phhep-lathep-ph0 citations
35
Color-factor symmetry using perturbiner methods for tree-level amplitudes of Yang-Mills theory coupled to matter
Abigail R. Chriss🇺🇸 · Mia Karlsson · Stephen G. Naculich🇺🇸
Bern-Carrasco-Johansson relations are helicity-independent constraints among the partial amplitudes of tree-level processes containing gluons and possibly also matter fields. They are a consequence of color-kinematic duality, but alternatively can be derived using the color-factor symmetry of tree-level amplitudes. We use recursive perturbiner methods to present a general, streamlined proof of the color-factor symmetry of all tree-level amplitudes containing an arbitrary number of fundamental spin-zero or spin-one-half matter fields and at least one gluon.
↳ hep-thhep-ph0 citations
36
Are We Ready for AI-Driven Discovery? AI Verification Before the Next Fundamental Physics Breakthrough
Gaia Grosso🇺🇸 · Vinicius Mikuni🇯🇵 · Lukas Heinrich🇩🇪
Machine learning (ML) has become integral to fundamental physics, accelerating statistical workflows from data acquisition through inference and hypothesis testing. As ML systems grow increasingly autonomous, ensuring their reliability for discovery claims becomes critical. This review synthesizes the VERaiPHY (Validation & Evaluation for Robust AI in PHYsics) initiative's frameworks for rigorous ML assessment across particle physics, astrophysics, and cosmology. We establish when verification is essential by contextualizing ML within the statistical discovery workflow. We emphasize fundamental limitations: inductive bias is unavoidable, sample complexity bounds learning, and experimental constraints limit discovery. We reflect on physicists' evolving role as both experimental designers and evaluators whose judgments encode scientific rigor into AI systems. Responsible integration requires understanding ML's transformative potential alongside its intrinsic boundaries.
↳ physics.data-ancs.LGhep-ph2 citations
37
The muon Moonshot: Moon subsurface tomography with upward-going muons
Zimo Hu🇯🇵 · Leyun Gao🇨🇳 · Zhengyun You🇨🇳 · Qite Li🇨🇳 · Qiang Li · Yuhong Yu🇨🇳 · Liangwen Chen🇨🇳 · Xueheng Zhang🇨🇳 · Zhiyu Sun🇨🇳
We propose a novel muon Moonshot concept for lunar subsurface tomography based on upward-going muons originated from the lunar regolith. Unlike the Earth, the Moon lacks an atmosphere, leaving a dense regolith below and a near-vacuum environment above. Consequently, while most downward-going hadrons are absorbed before decaying, upward-going hadrons escaping the regolith can decay in flight, producing a significant source of lunar muons. These muons are detectable by instruments on the lunar surface or in near-lunar orbit. We perform Monte Carlo simulations to investigate their energy spectra, angular distributions, and integrated fluxes under various theoretical and detector configurations. The results indicate that the lunar muon flux is sensitive to detector altitude under a flat-terrain assumption, demonstrating its potential as a novel non-invasive probe of shallow subsurface voids. We also present case studies on the detection of underground cavities and water resources, with cavity-induced flux variations observable in less than two minutes and weaker water signals distinguishable after about 36 minutes of data collection with a $1 m^{2}$ detector, and discuss potential implementations in future lunar missions.
↳ astro-ph.EPastro-ph.IMhep-exhep-ph+10 citations
38
Quantum Horizon and Quantum Membrane Paradigm from Black Hole Quantum Mechanics
Chong-Sun Chu🇹🇼
We develop a microscopic quantum membrane paradigm from the matrix quantum mechanics of black holes [1]. It was proposed that a quantum black hole is described by a fuzzy sphere together with a half-filled Fermi sea of horizon partons. We show that the topology of the fuzzy sphere induces a Berry monopole, providing a microscopic origin for the monopole appearing in the tunneling description of the decay of quantum black hole. Because the partons couple to the fuzzy sphere as fundamental degrees of freedom, they are sensitive to this monopole and form Lowest-Landau-Level (LLL) states rather than ordinary propagating two-dimensional fermions. Their guiding-center dynamics generates Ohmic, Hall, and polarization currents on the horizon. To couple these currents to an external electromagnetic field, we introduce a two-block matrix configuration comprising black-hole, environmental, and bifundamental link sectors. Off-diagonal link modes become tachyonic near the fuzzy sphere and condense, dynamically locking the horizon gauge field to the boundary value of the external Maxwell field. The parton current thereby becomes a physical boundary source for the exterior field. Our construction replaces the fictitious membrane of the classical paradigm with a dynamical quantum membrane populated by microscopic LLL degrees of freedom. The resulting boundary condition generalizes the classical ingoing membrane condition and yields explicit quantum, frequency-dependent, and helicity-dependent corrections, offering a possible probe of the microscopic quantum structure of the horizon.
↳ hep-thcond-mat.othergr-qchep-ph3 citations
39
The Neutron Electric Dipole Moment from Lattice QCD using a Background Electric Field
Thomas Blum🇺🇸 · Fangcheng He🇺🇸 · Taku Izubuchi🇺🇸 · Luchang Jin🇺🇸 · Hiroshi Ohki🇯🇵 · Sergey Syritsyn🇺🇸
We present the calculation of the neutron electric dipole moment (nEDM) $d_{n}$ using 2+1 flavor domain wall fermion ensembles with fixed lattice spacing $a \approx 0.11 fm$ and pion masses of 340, 420, and 576 MeV. We show that the neutron electric dipole moment can be extracted from the energy shift induced by a static uniform external background electric field in the presence of the CP-violating QCD theta-term, $θ ˉ Q_{t o p}$ . Motivated by the Feynman-Hellmann theorem, we employ sampling of the topological charge $q_{top} (t)$ on a single time-slice rather than the global topological charge $Q_{top} = \int q_{top} (t) d t$ , which dramatically improves the statistical precision of the $θ$ -induced nEDM. Key to our method is to calculate the forward matrix element of the topological charge density in the nucleon deformed by a background electric field. We find that calculation with the traditional positive parity-projected nucleon operator is subject to large excited-state contamination. To remove the contamination, we construct the ground state of the deformed nucleon by solving a non-Hermitian generalized eigenvalue problem. With this approach, we find consistent values for the nEDM when using different nucleon interpolating operators, regardless of whether they are covariant or non-covariant under chiral transformations. Finally, after extrapolating to the physical point, we obtain $d_{n} = - 0.0050 (4)^{stat} (8)^{sys} θ ˉ$ $e$ fm, where the systematic uncertainty includes excited-state effects estimated as variation with the Euclidean-time fits and the dependence on the strength of the electric field applied to the neutron. Conventional systematic errors like discretization, finite-volume, and chiral extrapolation effects will be addressed in future work.
↳ hep-lathep-exhep-ph3 citations
40
Conformal dark matter and MHz gravitational waves
Imtiaz Khan🇨🇳 · Niamat Ullah🇵🇰 · Salvatore Capozziello🇮🇹 · G. Mustafa🇨🇳 · Farruh Atamurotov🇺🇿
A localized enhancement of the primordial curvature spectrum can leave two distinct relics: gravitationally produced conformal-fermion dark matter and a scalar-induced stochastic gravitational-wave background. We show that the dark-matter abundance fixes the scalar normalization through the cubic moment of the curvature spectrum, while the induced tensor signal probes its quadratic convolution. This closes the usual normalization freedom in scalar-induced gravitational-wave templates and ties the MHz signal directly to the dark-matter mass, peak scale, and spectral width. A concrete single-field realization demonstrates this mechanism: a Mukhanov--Sasaki evolution produces a broad MHz background that sits safely below the Gaussian primordial-black-hole threshold. In this construction, a null high-frequency search becomes a lower bound on the conformal-fermion mass, while a detection has to reproduce the relic abundance, peak frequency, amplitude, and width from one primordial feature. The result is a testable link between small-scale inflationary structure, superheavy dark matter, and laboratory MHz gravitational-wave searches
↳ astro-ph.COhep-ph0 citations
41
From hyperon--nucleon interactions to deuteron--hyperon femtoscopy
Jiaxing Zhao🇩🇪
We investigate the low-energy scattering and femtoscopic correlation functions of the $d - Λ$ , $d - Σ$ , and $d - Ξ$ systems within a microscopic folding approach. The effective deuteron--hyperon interactions are constructed by folding the HAL-QCD hyperon--nucleon potentials with the deuteron wave function, while the spin and isospin structures are treated through Wigner- $6 j$ recoupling coefficients. Using the resulting interactions, we calculate the scattering parameters and momentum correlation functions for all spin channels. No bound states are found for the $d Λ$ , $d Σ$ , or $d Ξ$ systems. Nevertheless, the $d Λ$ correlation exhibits a pronounced low-momentum enhancement associated with a large scattering length and a near-threshold pole, whereas the $d Σ$ correlation is suppressed by its predominantly repulsive interaction. The neutral $d Ξ^{0}$ system shows only a moderate enhancement, while the charged $d Ξ^{-}$ correlation is strongly amplified by the attractive Coulomb interaction. We further investigate feed-down effects from $Σ^{0}$ , $Σ (1385)$ , and $Ξ$ decays using Monte Carlo response matrices and demonstrate that these decays clearly modify the observable $d Λ$ correlation. Our results provide quantitative predictions for future femtoscopic measurements and establish deuteron--hyperon correlations as a sensitive probe of hyperon--nucleus interactions.
↳ nucl-thhep-ph0 citations
42
Jordan Pair Quantum Theory and the Standard Model
John C. Baez🇬🇧 · Endre Bokor🇬🇧 · Latham Boyle🇬🇧
Jordan pairs and hermitian Jordan triples were discovered by mathematicians studying Jordan algebras, which describe the possible algebras of observables in quantum mechanics. We point out a striking correspondence between the doubly exceptional hermitian Jordan triple (the so-called ``bi-Cayley'' triple) and the structure of the Standard Model of particle physics. We also point out how ordinary quantum mechanics may be reformulated, and generalized, using hermitian Jordan triples.
↳ math-phhep-phhep-thmath.MP+10 citations
43
Constraints on Annihilating Dark Matter from Gamma-Ray Background-Galaxy Shape Correlations: Model-independent Null Results and Moderate Template-based Signals
Masato Shirasaki🇰🇷 · Deheng Song🇧🇪 · Oscar Macias🇺🇸 · Shunsaku Horiuchi🇺🇸 · Naoki Yoshida🇯🇵
We revisit the cross-correlation between the unresolved $γ$ -ray background and galaxy shapes to constrain the annihilation cross section of particle dark matter. Our analysis uses $γ$ -ray photons from 14 years of observations with the Fermi Large Area Telescope (LAT), together with galaxy shape catalogs from the Dark Energy Survey Year 3 (DES Y3) and the Dark Energy Camera All Data Everywhere (DECADE) project, enabling us to probe cosmological large-scale signals over a common sky area of $\sim 12, 000 deg^{2}$ shared by the $γ$ -ray and galaxy data sets. In order to better access signals from large-scale structure, we employ a Fourier-space estimator for the cross-correlation in contrast to the previous DES Y3 analysis. We find that our measurements are consistent with a null detection in a model-independent $χ^{2}$ test, while template-based analyses yield signals at the $\sim 3 σ$ level. Our null results exclude an enhanced annihilation cross section for wino-like dark matter with a mass of $2 - 3$ TeV under a modest substructure boost factor of $\sim 30$ in Milky Way-sized halos. For larger boost factors of $\sim 100$ , the constraints become significantly stronger and exclude the canonical thermal annihilation cross section $⟨ σ v ⟩ = 3 \times 1 0^{- 26} cm^{3} / s$ for a $7 - 40$ GeV dark matter particle annihilating into $b b ˉ$ or $τ^{+} τ^{-}$ . The template-based analysis favors a power-law $γ$ -ray energy dependence of the cross-correlation, but also indicates deviations from that expected based on the mean intensity of the unresolved $γ$ -ray background around 100 GeV. We further consider decaying dark matter scenarios and derive $2 σ$ lower limits on the particle lifetime of $\sim 1 0^{26} - 1 0^{27} s$ , depending on the decay channel.
↳ astro-ph.COhep-ph0 citations
44
Evading Cosmological Strong Coupling in Non-minimally Coupled Vector Gravity
Antonio De Felice🇯🇵 · Seishi Enomoto🇯🇵 · Nagisa Hiroshima🇯🇵 · Atsushi Naruko🇯🇵
Recent analyses of Proca theories with non-minimal curvature couplings have uncovered an additional scalar degree of freedom with an identically vanishing propagation speed, $c_{s}^{2} = 0$ , signaling a scale-dependent strong-coupling problem. In this {\it Letter}, we show that an additional derivative interaction can lift this zero-speed degeneracy and restore a non-degenerate quadratic dynamics for the scalar perturbations. In an open region of parameter space, the scalar kinetic matrix is positive definite and the high-frequency propagation speeds are real and positive. At quadratic order, this removes the specific signature of strong coupling associated with the $c_{s}^{2} = 0$ mode. We also uncover a non-uniform limit as the temporal vector condensate approaches zero: at fixed nonzero $A_{0}$ , the formal extreme-ultraviolet regime develops a ghost, while the kinetic structure of the exactly vanishing-condensate branch is different. The momentum scale at which this ghost appears is pushed toward increasingly high values as $A_{0} \to 0$ . Whether the ghost scale ultimately lies above the EFT cutoff depends on an independent determination of the EFT cutoff. Finally, we identify a stable de Sitter fixed point with $A_{0} \neq = 0$ , surrounded by a finite region in which the scalar no-ghost and high-frequency stability conditions remain satisfied.
↳ hep-thastro-ph.COgr-qchep-ph0 citations
45
Spinoptics in the presence of axion-like particles in curved spacetime
Tomoki Takeuchi🇯🇵 · Tsutomu Kobayashi🇯🇵
We study the propagation of high-frequency electromagnetic waves coupled to an axionic scalar field in curved spacetime. By applying the effective action approach, we go beyond the standard geometric optics limit and derive spinoptics equations for the axion--Maxwell theory that are valid for arbitrary curved spacetimes and arbitrary axion profiles. These equations allow us to analyze helicity-dependent corrections to photon trajectories arising from the photon's interactions with both the axion field and spacetime curvature. We present representative examples to demonstrate how light trajectories deviate from null geodesics due to spinoptics effects in the presence of an axion field.
↳ gr-qchep-ph1 citation
46
Reconstruction of Primordial Power Spectrum from Gravitational Waves of High-Redshift Black Hole Binaries
Qianhang Ding🇰🇷 · Xinpeng Wang🇯🇵 · Masahide Yamaguchi🇰🇷 · Ying-li Zhang🇨🇳
High-redshift binary black hole (BBH) events are promising candidates for primordial black holes (PBHs) detectable by next-generation gravitational wave (GW) detectors. A redshifted mass distribution of detected PBH candidates can be obtained from GW observations, from which the underlying PBH mass function can be reconstructed. In this work, we develop a framework that applies the gradient-descent method to the observed redshifted mass distribution and reconstructs the PBH mass function and, subsequently, the primordial power spectrum (PPS) on small scales. As an illustrative application, we analyze BBH events in the LIGO--Virgo--KAGRA (LVK) catalogs under a specified PBH selection criterion. We find a regularization-stable candidate bump-like enhancement of order $O (1 0^{- 2})$ in the reconstructed PPS, centered around $k_{peak} ≃ 5.7 \times 1 0^{5} Mpc^{- 1}$ under the adopted assumptions. Our results demonstrate the feasibility of reconstructing the small-scale PPS from high-redshift BBH observations with next-generation GW detectors.
↳ astro-ph.COhep-ph0 citations
47
Conjugate Boundary Conditions, Kaluza-Klein Fermions, and an Extended Seesaw Model
Yugo Abe · Yuki Adachi🇯🇵 · Yukihiro Fujimoto🇯🇵
In this paper, we discuss the conjugate boundary condition (CBC), which has recently been studied as a way of realizing a Majorana fermion within a compactified five-dimensional theory ( $M^{4} \otimes S^{1} / Z_{2}$ ). The Majorana fermion which plays a crucial role in the seesaw scenario arises as a zero mode (lowest mode) by imposing the CBC. Although each nonzero Kaluza-Klein (KK) mode is also naively expected to be described by two Majorana fermions, we show by direct calculation that they can be combined into a Dirac spinor in the free theory or up to the level of the quadratic term in the Lagrangian. This difference comes from the fact that an accidental U(1) symmetry exists in the KK mode sector, though such a symmetry does not appear in the zero mode sector. We also point out that the compatibility between the CBC and the axial U(1) transformation plays a crucial role in the diagonalization of the KK mode. We also investigate interactions compatible with both the CBC and the chiral orbifold projection. We find that a nontrivial bulk interaction between a CBC fermion and a chiral-orbifold fermion is allowed. As an application, we construct an extended seesaw scenario by utilizing both boundary conditions and such nontrivial bulk interactions. The resulting seesaw scenario has a different property in contrast with the conventional extended seesaw scenario; namely, the above new non-trivial interactions cause lepton number violation (LNV), while the Majorana mass term in our model does not violate lepton number.
↳ hep-thhep-ph1 citation
48
Axion Generation in a Three-Dimensional Optical Trap
Chunyu Zhang · Xinran Fang · Lichen Peng · Xuri Yao🇨🇳 · Xiaoying Tang🇨🇳
The axion is a theoretical particle that could resolve multiple fundamental problems, most notably the strong Charge-conjugation-parity-symmetry (CP) problem in quantum chromodynamics and the nature of dark matter.To date, however, the axion has never been detected in any free-space experiment. In this work, we designed and constructed a laser-based system that generates a three-dimensional, closed trapping potential field with a null central region. Owing to its spindle-like geometry, we term this configuration an optical spindle trap (OST). Along the propagation axis, the photon population evolves in a distinct manner from the left to the right terminus of the trap: it first diminishes and then recovers to its baseline value.This behavior is analogous to the photon axion photon conversion process sought in light shining through wall experiments(LSW)1-3, in which a measured photon deficit would constitute evidence for axion conversion. The photon population was monitored with a single-photon counter (SPC) operated well below its saturation threshold, and the observed behavior was corroborated by charge-coupled device (CCD) imaging at extremely low optical powers, thereby excluding detector artefacts as the origin of the photon deficit.Under the constraint of energy conservation, the missing photons are attributed to conversion into axions that remain undetectable by both the SPC and the CCD. The underlying conversion mechanism is ascribed to spin-coupled axion photon interactions. This tens-of-millimeter-scale optical spindle trap thus provides a viable free-space axion source, generated by a table-top laser, for the study of the strong CP problem and axion-like dark matter candidates.
↳ physics.opticshep-exhep-ph0 citations
49
Chiral and $U (1)_{A}$ symmetries in background magnetic fields from lattice QCD
Heng-Tong Ding🇨🇳 · José Javier Hernández Hernández🇨🇳 · Dan Zhang🇨🇳
We study chiral symmetry and singlet $U (1)_{A}$ symmetry in QCD in a background magnetic field using lattice QCD. We first clarify the neutral-sector symmetry structure in a pure magnetic background, where the unequal electric charges of the light quarks explicitly reduce the non-singlet flavor symmetry. We identify the neutral-pion--sigma susceptibility difference, $χ_{π^{0}} - χ_{σ}$ , as the chiral-partner splitting associated with the surviving neutral non-singlet axial symmetry, and the neutral-pion--delta susceptibility difference, $χ_{π^{0}} - χ_{δ^{0}}$ , as the singlet $U (1)_{A}$ partner splitting. We also discuss the disconnected contribution to the neutral-pion susceptibility and its continuum constraint. Numerical results are obtained on fixed-scale $(2 + 1)$ -flavor HISQ ensembles with $m_{l} = m_{s}^{phys} /10$ , corresponding to a pion mass of about $220 MeV$ at vanishing magnetic field. We find that the neutral chiral-partner splitting increases with the magnetic field strength $e B$ at low temperature and decreases at sufficiently large $e B$ near the crossover, providing susceptibility-splitting counterparts of magnetic catalysis and inverse magnetic catalysis, respectively. The singlet $U (1)_{A}$ partner splitting shows an analogous low-temperature enhancement and large-field suppression near the crossover, with the suppression setting in at larger $e B$ and remaining milder than in the chiral channel. These results provide a first lattice-QCD study of neutral-sector probes of chiral and singlet $U (1)_{A}$ partner susceptibility splittings in background magnetic fields.
↳ hep-lathep-phhep-thnucl-th0 citations
50
Ab initio calculations of two-neutrino and neutrinoless double- $β$ decay of $^{48}$ Ca and related Gamow-Teller strength distributions
Zhen Li🇩🇪 · Lotta Jokiniemi🇩🇪 · Achim Schwenk🇩🇪
We present ab initio calculations of two-neutrino double-beta ( $2 ν β β$ ) decay of $^{48}$ Ca and the related Gamow-Teller (GT) strength functions in $^{48}$ Sc using the valence-space in-medium similarity renormalization group (VS-IMSRG) with nuclear interactions and electroweak currents based on chiral effective field theory. We find that the usual $p f$ -shell valence space significantly underestimates the nuclear matrix element (NME) of $2 ν β β$ decay compared to experiment, while an enlarged $d_{3/2} p f$ valence space yields very good agreement with the experimental value without any adjustments. We trace this to an improved description of the involved GT strength distributions, so that the enlarged valence space captures important correlations. The enlarged $d_{3/2} p f$ valence space leads to neutrinoless $β β$ NMEs of $^{48}$ Ca that are twice as large compared to the $p f$ -shell calculation. Our findings suggest that studies with different valence spaces and related GT strengths are important for assessing ab initio NME calculations of heavier $β β$ decays.
↳ nucl-thhep-phnucl-ex2 citations
51
Tidal deformation and strain accumulation of solid compact stars
Hongxiang Shen🇨🇳 · Yong Gao🇩🇪 · Hong-Bo Li🇨🇳 · Ren-Xin Xu🇨🇳
The tidal deformability of compact stars encodes the equation of state of dense matter, and gravitational-wave observations such as GW170817 have begun to constrain it under the assumption of a fluid interior. Yet whether the interior of pulsar-like compact stars is fluid or solid remains largely untested, despite the distinct tidal responses the two states predict. In this work, based on the strangeon-star model, we develop a framework for modeling tidal deformation in solid compact stars. Adopting a shear modulus of $μ = 1 0^{34} erg cm^{- 3}$ , we find a relative difference of approximately $40%$ in tidal deformability between solid and fluid strangeon stars of $1.4 M_{⊙}$ , corresponding to a $\sim 10%$ deviation from the universal I--Love relation. We further model the accumulation of internal strain during binary inspiral and find that it peaks near the stellar center. When the gravitational-wave frequency reaches several hundred $Hz$ , large-scale fracturing occurs and can release up to $\sim 1 0^{46} erg$ of elastic energy, sufficient to power short $γ$ -ray-burst precursors. This solid-to-fluid transition alters the tidal response and imprints on the waveform and phase of the emitted gravitational radiation. Combined with the precursor electromagnetic emission, these gravitational-wave signatures offer a multi-messenger avenue to test the solid nature of pulsar-like compact stars.
↳ astro-ph.HEgr-qchep-phnucl-th0 citations
52
Breaking the Dark Sector Degeneracy with Nonparametric Expansion--Growth Reconstruction
Changyu You🇨🇳 · Rong-Gen Cai🇨🇳 · Tao Yang🇨🇳
The dark energy equation of state (EoS) and a possible dark-sector interaction are degenerate at the level of background expansion: the same expansion history may be interpreted as time-varying dark energy, energy exchange with dark matter, or a mixture of both. We introduce a data-driven, nonparametric expansion--growth framework that breaks this degeneracy by simultaneously reconstructing the dark energy EoS and the dark-sector coupling. Allowing the interacting matter density to evolve freely, we incorporate the coupling into the linear matter perturbation equation and reconstruct the expansion and growth histories using Gaussian processes, with hyperparameters marginalized in a Bayesian treatment. Applying this method to Pantheon+, cosmic chronometers, BAO measurements including DESI DR2, and redshift-space-distortion data, we infer both $w_{de} (z)$ and the interaction history over $0 ≲ z ≲ 2$ , without assuming either a parametric EoS or a prescribed interaction form. We find no statistically significant evidence for either a nonzero interaction or dark energy dynamics: the reconstructed coupling and dark energy EoS remain consistent with the $Λ$ CDM limit. Our results establish an expansion--growth consistency test for coupled dark-sector physics and provide a model-independent route to distinguish genuine dark energy dynamics from effective dark-sector energy exchange.
↳ astro-ph.COgr-qchep-ph0 citations
53
Constraints on Ultra-Light Axions from the DESI DR1 Full Shape, Planck and ACT
Francesco Verdiani🇮🇹 · Emanuele Castorina🇮🇹 · Ennio Salvioni🇪🇸 · Emiliano Sefusatti🇮🇹 · Matteo Viel🇮🇹
We present updated bounds on ultra-light axions (ULAs) as a subcomponent of dark matter, derived from the full-shape analysis of the DESI Data Release 1 galaxy power spectra combined with Cosmic Microwave Background (CMB) data from ACT and Planck. We focus on the mass window $1 0^{- 32} eV \leq m_{a} \leq 1 0^{- 24} eV$ , employing state-of-the-art analysis methods rooted in the Effective Field Theory of Large Scale Structure. For the smallest masses, our joint analysis with DESI improves over CMB-only constraints by more than a factor of 2, establishing the most stringent limits to date. For instance, for $m_{a} \sim 1 0^{- 29} eV$ ULAs are constrained to be a fraction as small as $0.3%$ of the total matter energy density. The DESI Luminous Red Galaxy sample shows a mild preference for an ULA subcomponent with $m_{a} \approx 1 0^{- 26} eV$ , mirroring previous hints from BOSS, but this preference vanishes upon combination with CMB data. Probing the largest masses, $m_{a} ≳ 1 0^{- 25} eV$ , in future studies will benefit from extending the data analysis to smaller scales, both for galaxy clustering and CMB lensing, but will also require concurrent improvements in the theoretical modeling.
↳ astro-ph.COhep-ph1 citation
54
Signatures of $10 - 1 0^{4} M_{⊙}$ Dark Matter halos in LISA via Stochastic Diffraction
Han Gil Choi🇩🇪 · Juan Urrutia🇪🇪 · Miguel Zumalacárregui🇩🇪
Cold Dark Matter predicts a population of low-mass halos which are sensitive to its fundamental nature and the primordial power spectrum, yet remain undetected. Although elusive, their discovery may be possible thanks to wave-optics lensing of gravitational waves (GWs) by the superposition of many halos along the line of sight. We study the statistical properties of stochastic diffractive lensing, which imprints correlated fluctuations on the amplitude and phase of the original waveform. The stochastic distortions can be described by an orthogonal basis that captures the dominant ''tones'' associated with the dark matter properties, or dark timbre, which is not degenerate with binary source parameters. LISA is most sensitive to halos of $O (10 - 1 0^{4} M_{⊙})$ , and because the imprint recurs in every source, stacking $\sim (50, 500)$ loud binaries could confirm them at the $(2, 5) σ$ level ( $\sim 0.2$ to $≳ 4 σ$ for realistic merger rates and different concentration estimations). The per-event signal is only $O (1 0^{- 3})$ in cold dark matter, demanding major advances in waveform accuracy and data analysis. Even short of that reach, stochastic diffraction places stringent bounds on models that enhance small-scale structure, such as axion miniclusters and primordial black holes.
↳ astro-ph.COastro-ph.HEhep-ph3 citations

Affiliations

first authorsco-authorsvia INSPIRE