HEP Phenomenology·hep-ph

Wed·Jul 22, 2026Wednesday·July 22, 2026

49 papers—31 primary·18 cross-listed

01
Zero of the proton electric form factor in the finite value of the spacelike momentum transfer squared
Erik Bartoš🇸🇰 · Stanislav Dubnička🇸🇰 · Noel Vincze🇸🇰 · Andrej Liptaj🇸🇰 · Anna Zuzana Dubničková🇸🇰
The behavior of the polarization data on $μ_{p} (G_{E}^{p} (t) / G_{M}^{p} (t))$ ratio, at the present day available up to $t = - 8.5$ GeV $^{2}$ , obtained in the Jefferson Lab experiments carried out by the Akhiezer-Rekalo polarization method, has a decreasing tendency, indicating possible existence of a zero of the proton electric form factor $G_{E}^{p} (t)$ in the finite spacelike momentum transfer squared value. However, recently appeared two papers, investigating these data, one of them including also other existing data on the nucleon electromagnetic structure in the spacelike and timelike regions, in which an existence of such zero is disproved. Nevertheless, reinvestigations we provide in this paper give clear arguments for the possible existence of such a zero.
hep-phnucl-th0 citations
02
Probing the Cosmic Axion Background via Axion-Photon Conversion in Filaments
Duncan Rocha🇺🇸 · Gordan Krnjaic🇺🇸 · Matthew J. Baldwin🇺🇸
The cosmic axion background (CaB) is a hypothetical population of relativistic axions produced in the early universe. If the CaB is produced from dark matter decays, the axions in this population can convert to photons in the magnetic fields of cosmological filaments, resulting in an isotropic gamma ray background flux. We present new indirect detection constraints on the axion mass and axion-photon coupling, for GeV-TeV dark matter with a decay lifetime below $1 0^{30}$ sec, by comparing this flux against experimental data. We exclude significant parameter space for axion masses below $1 0^{- 5}$ ~eV for a broad range of dark matter masses and lifetimes, assuming conservative filament magnetic field strengths ( $\sim 1$ nG). For large filament fields ( $\sim 100$ nG), our strategy also constrains a portion of the QCD-axion parameter space for TeV-scale dark matter masses.
hep-ph0 citations
03
Soft Gluon Wave Function and Evolution Operator in the CGC at Next-to-Leading Order
Ramkumar Radhakrishnan🇺🇸
We construct the soft gluon light cone wave function of a fast moving hadron and the associated unitary evolution operator $Ω$ up to $O (g^{2})$ in pure Yang Mills theory $(N_{f} = 0)$ , within the Color Glass Condensate (CGC) framework. Working in light cone gauge, we perform a Born Oppenheimer separation between fast valence and soft modes and implement the eikonal approximation, which allows $Ω$ to be written as a fully normal ordered series in soft gluon creation and annihilation operators. The expansion coefficients are functionals of the non-commuting valence color charge density operators $ρ$ . We fix the coefficients by using the unitarity and explicit diagrammatic calculations within light-cone perturbation theory (LCPT). As an application, we diagonalize the pure Yang Mills soft Hamiltonian through orders $g$ and $g^{2}$ and show that the off diagonal mixing elements between Fock sectors cancel leading to the coherent background field energy proportional to $ρ^{2}$ .
hep-phhep-thnucl-th0 citations
04
Factorization of the triple-collinear $q \to q c c ˉ$ splitting function at first order in opacity
Shahin Iqbal🇵🇰 · Urs Achim Wiedemann🇨🇭
In strongly ordered collinear limits, triple-collinear $1 \to 3$ splitting functions factorize into products of $1 \to 2$ splitting functions. Here, we investigate whether, and under which conditions, this factorization persists in a finite QCD medium. To this end, we reformulate the opacity expansion as a medium-modification of the compact Catani-Grazzini representation of collinear $1 \to n$ splitting functions. We compute the fully differential medium-modified triple-collinear $q \to q c c ˉ$ splitting function to first order in opacity and leading order in $N_{c}$ , and show that it can be expressed as a sum of momentum-shifted vacuum $q \to q c c ˉ$ splitting functions multiplied by simple interference factors. In vacuum, this splitting function has a single strongly ordered collinear limit, in which the invariant mass of the outgoing $c c ˉ$ pair is much smaller than all other invariant masses. The medium-modified splitting function instead exhibits three distinct strongly ordered limits, depending on how the relevant invariant masses -- multiplied by a boost factor and interpretable as inverse formation times -- compare with the medium length. Remarkably, in all three cases the triple-collinear splitting factorizes also in the medium into a tensor product of $q \to q g$ and $g \to c c ˉ$ splitting functions. In two of these limits, the latter are medium modified to first order in opacity. This first proof shows that factorization extends to medium-modified triple-collinear splitting functions. Lastly, we relate our results to the longstanding problem of overlapping formation times and discuss their implications for jet-quenching parton showers based on medium-modified $1 \to 2$ splittings. We also outline further applications of our formalism and note that our results may inform future phenomenological studies of spin (de)correlations in final-state radiation in dense QCD matter.
hep-ph0 citations
05
Fate of Metastable Vacua in the Type-II Two-Higgs Doublet Model
Debtosh Chowdhury🇮🇳 · Kirtimaan A. Mohan🇺🇸 · Poulami Mondal🇮🇳 · Subrata Samanta🇮🇳
The scalar potential of the Two-Higgs-Doublet Model (2HDM) can admit multiple non-degenerate vacua due to the presence of the two Higgs doublets unlike the Standard Model (SM). For a physically viable parameter point, one of these vacua must correspond to the physical electroweak (EW) symmetry breaking vacuum with the vacuum expectation value of about $246$ GeV. Given the complex structure of the scalar potential, the physical EW vacuum may be metastable in nature rather than the global minimum of the potential. In this work, we delineate regions of the parameter space in the Type-II 2HDM accommodating multiple extrema of the scalar potential and analyze, in a gauge-independent manner, the stability of the EW vacuum there at the tree level and beyond. A Bayesian global fit of the Type-II 2HDM, including next-to-leading-order unitarity constraints and the latest experimental measurements, indicates that parameter space regions leading to metastable EW vacua are excluded at both the tree and one-loop levels.
hep-phhep-ex0 citations
06
Gravitational waves from self-resonance during reheating with a quantum-corrected inflaton potential
Tomoya Inada🇯🇵 · Noel Jonathan Jobu🇮🇳 · Kenji Nishiwaki🇮🇳 · Toshifumi Noumi🇯🇵 · Naoki Yamatsu🇯🇵
We investigate how localized quantum corrections to the inflaton potential affect preheating dynamics and the resulting stochastic gravitational wave (GW) spectrum. When these corrections sufficiently suppress the quadratic term of the potential near its minimum, inflaton self-resonance can produce a peaked GW spectrum. On the other hand, we find that a smooth and enhanced spectrum can appear if the quadratic term acquires a negative coefficient. As a concrete realization, we analyze the $α$ -attractor T-model with a one-loop Coleman--Weinberg correction induced by a heavy scalar and compute the resulting GW spectra using lattice simulations. The GW signals lie in the ultra-high-frequency regime at frequencies above the kHz range. These results suggest that GW signals from preheating may probe quantum corrections to the inflaton potential, thereby providing indirect information about the underlying UV physics.
hep-phastro-ph.COgr-qchep-th1 citation
07
Towards the Swampland of Flavour Symmetries
Xiyuan Gao🇩🇪
In this thesis, we demonstrate the predictive power of the flavour models without explicit flavour symmetries, which we call the `swampland of flavour symmetries'. Firstly, we revisit the minimal type II seesaw model, which extends the Standard Model (SM) with a TeV-scale triplet scalar field. We find that certain flavour textures of the neutrino mass matrix can suppress the tightly constrained $μ \to e$ transition rates and allow a $5 - 6$ TeV effective cut-off scale, even when the relevant flavour symmetries are all strongly broken. Next, we show two examples in which some SM flavour parameters are calculable, but the underlying symmetries remain implicit. (i) In the most minimal $S O (10)$ theory, although the quark-lepton symmetry does not manifest at low energies, we find that the $b - τ$ mass ratio can be correctly predicted when the leptoquarks contained in the scalar sector lie at TeV scale, as motivated by the long-standing $B$ anomalies. (ii) We identify a new class of anomaly-free chiral symmetries in the SM (including three right-handed neutrinos), referred to as enhanced $B - L$ , under which all neutrinos are massless. In this framework, the neutrino masses are not free parameters but arise solely through the dynamical symmetry breaking effects, known as neutrino condensate. Furthermore, we note that the swampland of flavour symmetries could also involve light new particles, in particular the flavourful axions. As a preliminary study, we calculate an overlooked two-loop contribution to the axion flavour violating interactions in a minimal axion model, and analyze its impact on explaining a recent excess at Belle II.
hep-ph0 citations
08
Feynman Integrals Meet Second-Order Partial Differential Equations
Xiang Chen🇨🇭 · Hantian Zhang🇨🇭
We propose a second-order partial differential equation method to solve multi-loop Feynman integrals as an equilibrium problem. As a proof-of-concept demonstration, we perform a Galerkin discretization of the corresponding variational form and employ the finite element method to compute two-loop four-point Feynman integrals. This method can solve the integral over a broad region of multi-dimensional phase space once and for all. This work establishes a new connection between perturbative quantum field theory and modern partial differential equation methods, with the potential to streamline a wide range of phenomenological applications.
hep-phhep-th0 citations
09
The Plan B Model: $Z^{'}$ collider phenomenology and discovery prospects
Ben Allanach🇬🇧 · Hannah Banks🇬🇧 · Jon Butterworth🇬🇧
The Plan B Model was proposed by Allanach et al. (2023) and explains some gross features of the fermion mass spectrum. It also affects the predictions of various observables involving the $b \to s$ quark-flavour transition. The model predicts a new TeV-scale $Z^{'}$ which decays into various different final states. We constrain the viable parameter space of the model by re-casting several LHC direct searches for the $Z^{'}$ in addition to using Contur to test the model against unfolded measurements of various differential cross sections that are predicted to be non-zero in the Standard Model. We delineate the regions of parameter space that are excluded by current LHC data, and estimate the projected reach of the high luminosity LHC.
hep-phhep-ex0 citations
10
Detecting Cosmological Stasis with Future Gravitational Wave Observatories
Gabriela Barenboim🇪🇸 · Anne-Katherine Burns🇪🇸
We map the observational predictions of cosmological stasis in the inflationary gravitational wave background onto the sensitivity bands of current and planned gravitational wave detectors. Using the closed-form piecewise spectral template derived in the companion paper, we generate detectability maps for four stasis scenarios: canonical, dynamical scalar, vacuum-energy/matter, and vacuum-energy/radiation across the frequency bands probed by NANOGrav, SKA, LISA, DECIGO, BBO, the Einstein Telescope, and Cosmic Explorer. For scenarios in which the spectrum is suppressed, $w_{s} < 1/3$ , the stasis feature is detectable by BBO in the region of $(w_{s}, Δ N)$ parameter space in which $w_{s} ≳ 0.2$ for tensor-to-scalar ratios close to the Planck upper limit, r = 0.036. For scenarios in which the spectrum is enhanced, $w_{s} > 1/3$ , the stasis feature is detectable by BBO across the entire $(w_{s}, Δ N)$ parameter space for tensor-to-scalar ratios of $O (0.01)$ . We characterize the Standard Model (SM) $g_{*}$ fine structure of the IGWB, showing that SM phase transitions introduce spectral steps of $\approx 20%$ (electroweak, at $\sim 2.6 \times 1 0^{- 6}$ ~Hz) and $\approx 53%$ (QCD, at $\sim 3.6 \times 1 0^{- 9}$ ~Hz). For stasis scenarios with end-of-stasis temperatures below the QCD scale these steps fall inside the stasis band and constitute additional spectral features that complement the primary signature. Finally, we model the finite-width end-of-stasis transition phenomenologically, demonstrating that the spectral break at $f_{e n d}$ is smoothed over a log-frequency window $Δ N_{trans} \times 3 (1 + w_{s}) /4$ , and that the consistency relation $C^{2} = C^{2} (α)$ remains testable provided $Δ N_{stasis} ≫ Δ N_{trans}$ , a condition easily satisfied for all scenarios of phenomenological interest.
hep-phastro-ph.COgr-qc1 citation
11
Standard Model Symmetries and the Nested Embeddings of $R \subset C \subset H \subset O$
N. Furey🇩🇪
Where does the Standard Model's internal structure come from? Treating $O \oplus H \oplus C \oplus R$ as a module for its own multiplication algebra enables a particular origin story for the Standard Model's pre-Higgs, $g_{S M} := su (3)_{C} \oplus su (2)_{L} \oplus u (1)_{Y},$ and post-Higgs, $g_{L E} := su (3)_{C} \oplus u (1)_{Q},$ symmetries. We recognize the endomorphisms and their modules alike as $Z_{2}^{n}$ -graded algebras. Then, annihilating certain highest grade (volume) elements, and enacting an equal-trace condition on anti-hermitian operators leads precisely to $g_{S M}$ and $g_{L E}$ . Weak hypercharge and electric charge operators, $Y$ and $Q,$ take on a remarkably simple form: $\sum \frac{1}{n} I_{n \times n}$ . Upon the introduction of Cayley-Dickson imaginary units, this 15 $R$ dimensional $O \oplus H \oplus C \oplus R$ embeds naturally as a vector space into several well-studied 16 $R$ dimensional algebras, which we generically refer to as $V .$ With this embedding, the Standard Model's internal symmetries may then be seen to arise in part from the sequence of nested inclusions: $R \subset C \subset H \subset O \subset V .$ We define the notion of endomorphic models of particle physics, and connect $E n d_{R} (V) ≃ C l (0, 8)$ to the earlier ideas of Bott Periodic Particle Physics. We comment on a possible connection between the existence of multiple complex structures and the baryon asymmetry problem. In closing, we identify an appearance in this model of the fully connected tree of division algebraic Hopf fibrations that starts at $S^{15},$ and simultaneously involves the four parallelizable spheres $S^{7}, S^{3}, S^{1}, S^{0} .$
hep-phhep-th0 citations
12
Deep inelastic scattering as a probe of entanglement: the complete QCD dipole cascade
Martin Hentschinski🇲🇽 · Krzysztof Kutak🇵🇱 · Wieslaw Placzek🇵🇱 · Martin Rohrmoser🇵🇱
We study entanglement entropy in Deep Inelastic Scattering (DIS) using the dipole formulation of the high-energy limit of QCD. We argue that a reduced density matrix arises in low $x$ DIS due to a trace over unobserved color degrees of freedom and we obtain entanglement entropy in terms of dipole multiplicities, directly from the von Neumann entropy. Dipole multiplicities are obtained from a solution to low $x$ evolution equations, which we solve numerically. Unlike previous studies, we take into account both transverse-size and azimuthal-angle dependence in the dipole evolution kernel. We study both the exact solution of the equation as well as its double leading-logarithmic approximation (DLLA). We find that for the same initial dipole size, the DLLA solution generates a larger entropy. Finally, we calculate the dipole multiplicities and entanglement entropy and compare our results to the Shannon entropy of hadron multiplicities, as measured by the H1 collaboration.
hep-phquant-ph5 citations
13
D $e^{+} e^{-}$ ffusion: Capturing the Beam-Beam Physics of $e^{+} e^{-}$ Collisions with Diffusion Models
Antonio Chahine🇬🇧 · Mariarosaria D'Alfonso🇺🇸 · Jan Eysermans🇺🇸 · Emmett Forrestel🇺🇸 · Loukas Gouskos🇺🇸 · Lindsey Gray🇺🇸 · Katie Kudela🇺🇸 · Haoyun Liu🇬🇧 · Benedikt Maier🇬🇧 · Dimitrios Ntounis🇺🇸 · Christoph Paus🇺🇸 · Umar Sohail Qureshi🇺🇸 · Caterina Vernieri🇺🇸
Beam-induced backgrounds at high-luminosity $e^{+} e^{-}$ colliders, such as the FCC-ee, are dominated by incoherent pair creation (IPC), and require computationally expensive simulations with dedicated Monte Carlo (MC) event generators. Reliable detector and machine-detector interface studies necessitate event samples that are several orders of magnitude larger than what is practically attainable with existing MC. To alleviate this bottleneck, we present D $e^{+} e^{-}$ ffusion, a denoising diffusion probabilistic model that operates as a permutation-equivariant, set-valued surrogate for fast IPC simulation. Trained on a small GuineaPig++ sample, D $e^{+} e^{-}$ ffusion faithfully reproduces the marginal and joint kinematic, angular, and positional distributions of all three IPC production processes. In addition, we assess the fidelity at the detector level by propagating both Geant4 and D $e^{+} e^{-}$ ffusion events through a Geant4 simulation of the CLD vertex detector and by training a transformer-based two-sample classifier; the classifier achieves an area under the ROC curve of $0.553 \pm 0.016$ . The trained model generates events nearly four orders of magnitude faster than Geant4, paving the way for a fast-simulation surrogate for FCC-ee design studies.
hep-phhep-exphysics.data-an0 citations
14
Transport phenomena and observables associated with viscous properties of an anisotropic hot QCD medium at finite baryon asymmetry
Shubhalaxmi Rath🇨🇱 · Nicolás A. Neill🇨🇱
We have studied the transport phenomena and observables associated with viscous properties of a baryon asymmetric hot QCD medium in the presence of a weak-momentum anisotropy arising due to the asymptotic expansion of the matter in the initial stages of ultrarelativistic heavy-ion collisions. This study facilitates the understanding of the sound attenuation in the medium through the Prandtl number, the nature of flow through the Reynolds number, fluid behavior through the specific shear viscosity, and conformal symmetry through the specific bulk viscosity for an anisotropic hot QCD medium at finite baryon asymmetry. We have determined the shear and bulk viscosities by solving the relativistic Boltzmann transport equation in the relaxation time approximation method. The interactions among partons are incorporated through their distribution functions within the quasiparticle model of hot QCD medium at finite temperature, anisotropy and baryon asymmetry. We have observed a decrease in the shear and bulk viscosities in the presence of expansion-induced anisotropy for baryonless scenario as well as for baryon asymmetric scenario. Conversely, these viscosities are larger in baryon asymmetric matter compared to their counterparts in baryonless matter. The impact of anisotropy on baryon asymmetric matter is observed to be as conspicuous as on baryonless matter. The above results are broadly attributed to the squeezing of the distribution function due to the momentum anisotropy generated by the asymptotic expansion of baryon asymmetric matter and the dispersion relations of partons in the presence of anisotropy. Additionally, the aforesaid observables are also significantly modulated by the expansion-induced anisotropy in the baryon asymmetric medium, indicating new predictions for the sound attenuation, flow characteristics, fluid behavior and conformal symmetry of the said medium.
hep-phhep-thnucl-th0 citations
15
Production of lepton-flavor-violating scalars through resonant positive-muon annihilation on atomic electrons
Jinhong Shen🇨🇳 · Youpeng Wu🇨🇳 · Zijian Wang🇨🇳 · Leyun Gao🇨🇳 · Qite Li🇨🇳 · Chen Zhou🇨🇳 · Qiang Li🇨🇳 · Yu Xu🇨🇳 · Xueheng Zhang🇨🇳 · Liangwen Chen🇨🇳 · He Zhao🇨🇳 · Zhiyu Sun🇨🇳 · Ruihu Zhu🇨🇳
We investigate an invisible lepton-flavor-violating scalar $ϕ$ with exclusive $e - μ$ couplings and study its resonant production via $μ^{+} e^{-} \to ϕ$ in fixed-target experiments. Since the effective center-of-mass energy is determined by the momentum of the initial-state bound electrons, atomic effects can significantly affect the resonance behavior. We therefore employ relativistic bound-state electron wave functions to calculate the production cross section and reveal a material-dependent broadening of the resonance lineshape. For the proposed HIAF experiment, fewer than one day of data taking ( $6 \times 1 0^{10}$ MOT) can probe couplings at the $1 0^{- 5}$ level at 90\% confidence level near resonance, demonstrating that high-intensity muon fixed-target experiments provide a powerful complementary probe of lepton-flavor violation.
hep-ph0 citations
16
A coupled-channel quark model study of possible $Ξ_{cc}^{(*)} K^{(*)}$ molecular states
Ye Yan🇨🇳 · Qi Huang🇨🇳 · Yuheng Wu🇨🇳 · Hongxia Huang🇨🇳 · Jialun Ping🇨🇳
Inspired by the recent experimental discovery of doubly charmed baryons, we investigate the possible $Ξ_{cc}^{(*)} K^{(*)}$ molecular systems within the framework of the quark delocalization color screening model. The energy spectra and scattering processes of the relevant baryon-meson systems are investigated to explore the dynamical properties of the possible molecular states. The spectrum calculations predict three bound states, namely the $I (J^{P}) = 0 (1/ 2^{-})$ $Ξ_{cc} K$ , the $I (J^{P}) = 0 (3/ 2^{-})$ $Ξ_{cc}^{*} K$ , and the $I (J^{P}) = 0 (5/ 2^{-})$ $Ξ_{cc}^{*} K^{*}$ molecular states. The scattering phase shift analysis further confirms two $Ξ_{cc} K^{*}$ resonance states with $I (J^{P}) = 0 (1/ 2^{-})$ and $0 (3/ 2^{-})$ , which originate from quasi-bound states through channel coupling. In particular, the $I (J^{P}) = 0 (1/ 2^{-})$ $Ξ_{cc} K$ bound state is consistent with previous theoretical studies, making it one of the most promising candidates for future experimental searches.
hep-ph0 citations
17
LFV decays in a 3-3-1 model with singlet leptoquarks
N.H.T. Nha🇻🇳 · L.T. Hue🇻🇳 · N. T. K. Ngan🇻🇳 · P.T. Bich🇻🇳 · T.T. Hong🇻🇳 · N.T. Tham🇻🇳
Motivated by a recent study of the 3-3-1 model supplemented with a singlet scalar leptoquark, which successfully explains the muon anomalous magnetic moment and the decay $μ \to e γ$ within current experimental constraints, we extend the phenomenological analysis of this framework to include the lepton-flavor-violating decays of the Standard Model-like Higgs and the $Z$ boson. An interesting feature is that the branching ratios of these decays exhibit a nearly linear correlation with the corresponding charged lepton flavor-violating radiative decays, namely $Br (h, Z \to e_{b}^{\pm} e_{a}^{\mp}) \propto Br (e_{b} \to e_{a} γ)$ . Furthermore, the model exhibits a complementary interplay between the charged-lepton anomalous magnetic moments: parameter regions with $∣Δ a_{μ} ∣ \geq 1 0^{- 11}$ favor $Br (h, Z \to τ^{\pm} μ^{\mp})$ reaching their current experimental upper limits while keeping $∣Δ a_{e} ∣$ negligible, whereas regions with $1 0^{- 14} \leq ∣Δ a_{e} ∣ \leq 8 \times 1 0^{- 13}$ instead allow $Br (h, Z \to τ^{\pm} e^{\mp})$ to approach the present experimental sensitivities but simultaneously suppress $∣Δ a_{μ} ∣$ to the level of $O (1 0^{- 16})$ .
hep-ph1 citation
18
Domain Walls From Confining Bubbles: $S U (N_{c})$ Yang Mills at Finite $θ$
Bruno Missoni🇮🇹 · Enrico Morgante🇮🇹 · Nicklas Ramberg🇮🇹
We study the confinement phase transition in SU( $N_{c}$ ) pure Yang-Mills theory at finite $θ \neq = 0$ using the Improved Holographic QCD (IHQCD) model. We show that the critical temperature, as a function of $θ$ for large but fixed $N_{c}$ , is reduced, thus decreasing the amount of supercooling in the confinement phase transition. Upon completion of the confinement phase transition, a network of domain walls can be produced, owing to the multi-branched vacuum structure of Yang-Mills theory at finite $θ$ . We highlight the potential interplay between the produced domain walls and the confinement phase transition dynamics. We emphasize that DW production from bubble coalescence in strongly coupled non-conformal FOPTs is a dynamical process of vacuum assignment, hydrodynamics, and local reheating effects, all potentially affecting the approach towards the scaling regime. Lastly, we demonstrate the level of tuning necessary for potentially interesting imprints from gravitational waves through domain wall annihilation and its interplay with the confinement PT.
hep-phastro-ph.COhep-th1 citation
19
A Non-Holomorphic Modular $A_{4}$ Framework for Resonant Leptogenesis with Gravitational Wave Signatures
Mitesh Kumar Behera🇮🇳 · Jaydeb Das🇮🇳 · Niloy Mondal🇮🇳
We study a type-I seesaw framework based on non-holomorphic $A_{4}$ modular symmetry, where polyharmonic Maaß\ forms construct the Yukawa couplings and right-handed neutrino (RHN) Majorana mass matrix. The use of non-holomorphic modular forms yields highly constrained neutral lepton mass matrices with a more restrictive lepton-sector structure and naturally generates a quasi-degenerate RHN mass spectrum, enabling resonant leptogenesis at an intermediate scale with RHN masses of $O (1 0^{3})$ TeV without requiring an ad hoc mass degeneracy. We further extend the model by introducing a complex scalar field $(Φ)$ charged under $Z_{3}$ symmetry. The spontaneous breaking of the discrete symmetry after the phase transition associated with $Φ$ leads to domain-wall (DW) formation. A radiatively induced bias term associated with the RHN sector triggers DW annihilation, resolving the cosmological DW problem, and producing a stochastic gravitational wave (GW) signal that indirectly probes the RHN mass scale. The accompanying first-order phase transition produces a second GW peak, yielding a characteristic double-peaked spectrum with frequencies separated by several orders of magnitude and potentially observable by complementary future GW detectors.
hep-ph3 citations
20
Chromoelectric and chromomagnetic matching to scalar and spin-two nucleon structure
Arkadiy I. Syamtomov🇺🇦
Compact heavy quarkonium couples through the multipole interaction to scalar and spin-two gluonic operators. At leading chromoelectric order the corresponding matching coefficients satisfy $C_{2}^{Φ} = - C_{S}^{Φ}$ ; an independent chromomagnetic polarizability lifts this relation within the general CP-even, spin-independent, local two-gluon interaction at dimension four and zero derivative order. We construct an RG-consistent realization in a fixed $M S$ convention. The QCD trace identity converts the gluon-only scalar matching condition into an invariant basis and fixes the correlated quark-mass coefficient required when the interaction is re-expressed in the scale-dependent basis away from the matching scale, whereas leading-logarithmic singlet evolution induces a quark spin-two coefficient. In threshold-aligned symmetric kinematics, the canonical-spin non-flip projection contains $A_{i} (t)$ and the combination $3 B_{i} (t) - D_{i} (t)$ . An explicit Breit-frame calculation relates this projection to an off-diagonal helicity representation for nonzero spacelike $t$ ; the off-diagonal form is kinematic rather than an additional dynamical spin flip. Linearity of the scalar and spin-two evolution factorizes the chromomagnetic dependence of their ratio as $R_{2/0}^{Φ} (t; ρ_{Φ}) = [(1 + ρ_{Φ}) / (1 - ρ_{Φ})] R_{2/0}^{Φ} (t; 0)$ within the gluon-only dimension-four matching setup. The result separates state-dependent quarkonium matching from scalar and gravitational nucleon structure and states explicitly the assumptions under which this factorization holds.
hep-phhep-th1 citation
21
Automated higher-order predictions for ultra-peripheral collisions with full impact-parameter dependence
Frank Krauss🇬🇧 · Peter Meinzinger🇨🇭
We present an automated framework within the Sherpa event generator for the simulation of photon-induced processes in high-energy collisions of protons and nuclei. The calculation builds upon the equivalent-photon approximation and incorporates different form factor parametrisations, taking into account the full dependence on the finite size of emitters and their impact parameter. Higher-order effects are taken into account automatically by either YFS-resummation of soft photon emissions to all orders or Next-to-Leading Order in electroweak theory. We validate our simulation framework using data from two representative ATLAS measurements of exclusive $μ$ -pair production in $pp$ and Pb+Pb collisions. Exemplary predictions for exclusive $W$ -pair production in $pp$ collisions and $τ$ -pair production in both $pp$ and Pb+Pb collisions are presented.
hep-ph1 citation
22
Probing the vector-like $X$ quark via the $t W$ channel at future muon-proton colliders
Liangliang Shang🇨🇳 · Shuting Zhao🇨🇳 · Bingfang Yang🇨🇳 · Stefano Moretti🇬🇧
We investigate the discovery potential for the vector-like $X$ -quark (VLX) at future muon--proton ( $μ p$ ) colliders through the process $μ^{+} p \to ν ˉ_{μ} X \to ν ˉ_{μ} t W^{+}$ . A simplified effective model is adopted in which the production and decay of the VLX are governed by the coupling strength $g^{*}$ , the generation-mixing parameter $R_{L}$ , and the VLX mass $m_{X}$ . A comprehensive Monte Carlo analysis is performed at $s = 5.29$ , $6.48$ , and $9.16 TeV$ , considering four complementary decay channels: the Fully Leptonic (FL), Fully Hadronic (FH), and two Semi-Leptonic (SL1 and SL2) modes. An $80%$ polarized muon beam together with boosted-object reconstruction based on fat-jet techniques is employed to improve the signal sensitivity. The expected exclusion and discovery reaches are evaluated using the Asimov significance. We find that the sensitivity can be improved substantially with increasing center-of-mass energy and larger values of $R_{L}$ . Among the four channels, the FH mode provides the strongest sensitivity, reaching a $2 σ$ exclusion limit of $m_{X} ≃ 8.3 TeV$ with $g^{*} = 0.009$ for $R_{L} = 0.1$ at $s = 9.16 TeV$ , whereas the FL mode gives the weakest reach because of its smallest branch ratio. These results demonstrate that future $μ p$ colliders can offer significant sensitivity to heavy VLX over a broad region of parameter space.
hep-ph0 citations
23
Muon pair production in electron-positron collisions close to threshold in the presence of a strong laser field
N. Mahlin🇩🇪 · S. Villalba-Chávez🇩🇪 · C. Müller🇩🇪
Within the framework of strong-field quantum electrodynamics, we study the creation of muon-antimuon pairs in laser-assisted collisions of electrons with positrons, whose center-of-mass energy is close to the threshold of the process. Our focus lies on incident collision energies slightly below the threshold, where the associated energy gap has to be overcome by multiphoton absorption from the applied high-intensity laser field while the collision occurs. We calculate the cross section of the process and discuss its nonperturbative dependencies on the energy gap and the laser parameters. Three qualitatively different interaction regimes are identified, where the influence of the laser field either has a classical or fully quantum nature. In the latter case, an exponential dependence of the cross section on the collision parameters is found, which resembles the Schwinger effect.
hep-ph0 citations
24
A note on analytic continuation to Minkowski space relevant for $^{3} P_{0}$ decay-model phenomenology
Alexandre Salas-Bernárdez🇪🇸 · Juan Ferrera🇪🇸 · Felipe J. Llanes-Estrada🇪🇸
We discuss some aspects of the uniqueness of analytically continuing Euclidean Green functions obtained by means of the Dyson-Schwinger equations (DSEs) and constrained by lattice data, back to Minkowski-space with physical $p^{2}$ .
hep-phActa Phys.Polon.Supp.(2026)·1 citation
25
Prospects for $K_{L} \to π^{0} ν ν ˉ$ , $K_{S} \to μ^{+} μ^{-}$ , $K_{L} \to π^{0} ℓ^{+} ℓ^{-}$ and $ε^{'} / ε$ after the new $K^{+} \to π^{+} ν ν ˉ$ result from NA62
Monika Blanke🇩🇪 · Andrzej J. Buras🇩🇪 · Cristina Lazzeroni🇬🇧 · Joel C. Swallow🇨🇭
The recently announced NA62 measurement of the $K^{+} \to π^{+} ν ν ˉ$ branching ratio, based on 2016--2024 data, is fully consistent with its very accurate Standard Model (SM) prediction. While it is not excluded that the final result based on 2016--2026 data will deviate from the SM prediction, the question arises whether a similar fate awaits the $K_{L} \to π^{0} ν ν ˉ$ decay. This decay is currently being searched for by the KOTO experiment, with the present upper bound roughly two orders of magnitude above its very precise SM prediction. The proposed KOTO II experiment aims to provide the first discovery of the $K_{L} \to π^{0} ν ν ˉ$ decay and measure its branching ratio. Building on the findings of several previous papers we demonstrate that in the presence of suitably chosen large new complex phases and of a small amount of new right-handed $s ˉ d$ couplings, in addition to the left-handed ones, the $K_{L} \to π^{0} ν ν ˉ$ branching ratio can still be enhanced by one order of magnitude with respect to the SM prediction while keeping both $K^{+} \to π^{+} ν ν ˉ$ and $ε_{K}$ SM-like. Simultaneously the decays $K_{S} \to μ^{+} μ^{-}$ , studied by LHCb, and $K_{L} \to π^{0} ℓ^{+} ℓ^{-}$ , searched for by KOTO II, can be strongly enhanced and the anomaly in the ratio $ε^{'} / ε$ , as claimed by Dual QCD, removed. We illustrate this with an example of a specific $Z^{'}$ scenario.
hep-phhep-exhep-lat1 citation
26
Holographic Soliton Crystals for Dense Nuclear Matter and Neutron Stars
Lorenzo Bartolini🇦🇹 · Sven Bjarke Gudnason🇨🇳 · Jonas Mager🇦🇹 · Anton Rebhan🇦🇹
We construct a nuclear-matter equation of state (EOS) from holographic QCD in the Witten-Sakai-Sugimoto (WSS) model, going beyond the homogeneous ansatz by building dense baryonic matter more directly from the solitonic description of holographic baryons. Employing the two-baryon interaction potential obtained from the linearized soliton tails sourced in the curved background by point-like (core) instantons, we assemble an infinite face-centered cubic (FCC) crystal with nearest neighbors in the most attractive channel as an approximation to the quantum liquid of baryons and compute the energy density $E (n_{B})$ , the chemical potential $μ_{B}$ , and the pressure $P$ . We calibrate the symmetric-matter EOS by fixing the 't Hooft coupling $λ$ and the WSS scale $M_{KK}$ to saturation-density and onset-chemical-potential properties, and by including a quark-mass term to reproduce the physical pion mass $m_{π} = 135 MeV$ . This fit turns out to remain reasonably close to the parameters required by the vacuum meson sector, while their modification is consistent with Brown-Rho scaling in a dense medium, and the incompressibility at saturation is of the correct order of magnitude, both in clear contrast to the homogeneous approximation. We then extend to beta-equilibrated matter, using phenomenological input for the symmetry energy, and obtain hybrid EOS and neutron-star observables that are compatible with the NICER constraints.
hep-phhep-th1 citation
27
Flavor-Dependent QCD Critical Endpoint and Dual-Channel Fluctuations from Multi-Charge Holography
Zhibin Li🇨🇳 · Danning Li🇨🇳 · Mei Huang🇨🇳
We construct a thermodynamically self-consistent holographic QCD framework incorporating multiple conserved charges. By introducing three independent bulk $U (1)$ gauge fields, our Einstein-Maxwells-dilaton (EMsD) model naturally accommodates the coupled chemical potential landscape $(μ_{B}, μ_{Q}, μ_{S})$ inherent to realistic heavy-ion collisions. Crucially, thermodynamic consistency is enforced at the level of holographic renormalization, ensuring exact Maxwell cross-derivative relations without ad hoc patching. Calibrated exclusively at zero density, the model exhibits genuine predictive power for finite-density thermodynamics. We reveal that finite charge and strangeness densities induce pronounced nonmonotonic shifts in the critical endpoint (CEP) location. Furthermore, by mapping the freeze-out trajectories, we demonstrate that the allowed parameter bands robustly encompass empirical hadron resonance gas (HRG) fits. Within this physical regime, higher-order cumulant ratios for both net-baryon and net-charge channels exhibit coherent critical peaks at $s_{N N} \approx 5 - 7 GeV$ . This hierarchical dual-channel signature provides a decisive, background-free strategy for the ongoing experimental search for the QCD critical point.
hep-ph1 citation
28
Full Next-To Leading-Order Electroweak and QCD Corrections to the Relic Density in the CxSM
Pavao Brica🇩🇪 · Karim Elyaouti🇩🇪 · Pedro Gabriel🇩🇪 · Margarete Mühlleitner🇩🇪 · Rui Santos🇵🇹
In this work, we present the calculation of the next-to-leading order (NLO) QCD and electroweak corrections to the thermally averaged cross section of Dark Matter (DM) annihilation in the framework of the complex singlet extended Standard Model (CxSM) with one DM candidate. We derive the corresponding NLO QCD and electroweak corrected relic density and discuss the impact of the corrections as well as the remaining theoretical uncertainty due to missing higher-order corrections. This is estimated through a variation of the renormalization schemes for the singlet vacuum expectation value $v_{S}$ and the Higgs mixing angle $α$ . For the bulk of the scanned parameter points, the QCD and electroweak corrections are found to be of typical size with the remaining theoretical uncertainty ranging at the percent level. The larger corrections that are found, can be attributed to a large counterterm for $v_{S}$ emerging in the case of large mass gaps in the decay channel used for the renormalization. The corrections are of phenomenological impact. There are parameter points that are allowed at leading order (LO), but are excluded after including the NLO corrections to the relic density, and vice versa. Our corrections have been implemented in the new code RelExt@NLO based on the LO code RelExt, which has been made publicly available. This work marks a first step towards the calculation of the QCD and electroweak corrected relic densities in models with DM candidates stabilized by a discrete $Z_{2}$ symmetry.
hep-ph0 citations
29
Impact of Z-boson transverse-momentum resummation on PDF determination
Juan M. Cruz-Martinez🇪🇸 · Emanuele R. Nocera🇮🇹 · Luca Rottoli🇮🇹 · Paolo Torrielli🇮🇹
We study the impact of small-transverse-momentum resummation for neutral-current Drell-Yan lepton-pair production on the determination of collinear parton distribution functions (PDFs). We focus on measurements of the Z-boson transverse-momentum spectrum performed by ATLAS and CMS at the LHC at centre-of-mass energies of 8 and 13 TeV, and include them in PDF fits based on the NNPDF methodology. Theoretical predictions are computed at next-to-next-to-leading order (NNLO) in perturbative QCD and are supplemented with small-transverse-momentum resummation corrections at next-to-next-to-next-to-leading logarithmic accuracy obtained with RadISH. Missing higher-order uncertainties are accounted for through a theory covariance matrix constructed from renormalisation- and factorisation-scale variations. We first revisit the treatment of the 8 TeV data, replacing the fixed-order predictions used in previous analyses with numerically stable NNLO calculations, and removing the additional numerical uncertainties introduced in earlier fits. We then assess the impact of the 13 TeV measurements, of resummation corrections, and of progressively lowering the minimum cut on the dilepton transverse momentum. We find that resummation improves the description of the Z boson transverse-momentum data and is essential for ensuring the overall consistency of the PDF fits. Nevertheless, it does not conclusively support extending the fitted kinematic region to transverse momenta below a few tens of GeV. The impact of resummation on PDFs is moderate, leading primarily to a stabilisation of the gluon PDF in a kinematic region of relevance for LHC phenomenology. Finally, we comment on the fact that the treatment of correlations among theoretical uncertainties may play a central role in PDF fits to measurements with percent- and sub-percent-level precision.
hep-phhep-ex0 citations
30
Astrophysical Neutrino Sources as Colliders
Carlos A. Argüelles🇺🇸 · P. S. Bhupal Dev🇺🇸 · Bhaskar Dutta🇺🇸 · Gonzalo Herrera🇺🇸 · Nicholas Kamp🇺🇸 · Jason Kumar🇺🇸 · Stephan A. Meighen-Berger🇦🇺 · Mudit Rai🇷🇴 · Ian M. Shoemaker🇺🇸
High-energy neutrinos arise from processes at large center-of-mass energies, offering a window to test physics at comparable scales or beyond those accessible in collider experiments on Earth. Here, we present a recipe for extracting two-sided bounds on the inelastic $pp$ and $p γ$ cross sections from neutrino point-source data, by independently constraining every astrophysical input (cosmic-ray luminosities and target densities) through electromagnetic observations or theoretical arguments. The cross section is then the only remaining free parameter. Applying this framework to the IceCube associations with TXS~0506+056, NGC~1068, and the Galactic Plane, to a stacked population of eleven X-ray bright Seyfert galaxies, to the ultra-high-energy KM3NeT event KM3-230213A, and to projected observations of ultra-high-energy neutrinos, we obtain constraints that span center-of-mass energies from $s \sim 1$ GeV to $\sim 1 0^{5}$ GeV, some of which are well beyond the reach of the LHC and, for the $p γ$ channel, beyond HERA. Several of these bounds are more stringent than unitarity limits.
hep-phastro-ph.HEhep-ex0 citations
31
Integral representation of the neutrino mass-squared differences
I. Alikhanov🇷🇺
Determining the absolute neutrino mass scale remains one of the most compelling challenges in particle physics. To constrain theoretical models, establishing precise relations among neutrino masses is essential. We propose a simple integral representation of the neutrino mass-squared differences $Δ m_{ij}^{2}$ that provides a complementary perspective on these oscillation parameters. We then demonstrate its utility through several examples. Specifically, assuming stringent cosmological bounds that confine the sum of neutrino masses near the normal ordering floor, we derive an analytical condition for the lightest neutrino mass, $m_{1} < 61Δ m_{21}^{2} /30$ . Using recent data from the JUNO experiment, this yields a competitive upper limit of $m_{1} < 0.0023$ eV (95\% C.L.). We also formulate practical analytical bounds for $m_{2}$ and $m_{3}$ adaptable to future data, and translate the results into allowed ranges for the effective electron and Majorana neutrino masses $m_{ν_{e}}$ and $m_{β β}$ . Finally, we show that neutrino mass relations of the Gatto-Sartori-Tonin type emerge directly from the proposed integral representation.
hep-phhep-ex0 citations
32
Sensing relativistic quantum fields with minimally perturbing local measurements
F. Daem🇫🇷 · L. Ballesteros Ferraz🇫🇷 · A. Zampeli🇵🇱 · A. Matzkin🇫🇷
We develop a framework for minimally perturbing local measurements in relativistic quantum field theory, with the aim to sense local properties of the field in a non-destructive manner. The field properties are sensed by weakly coupled pointers and encapsulated in conditional expectation values dependent on a postselection of the field state. Our operational protocol uses causally admissible Kraus updates for the field, in line with recent relativistic measurement theories, keeping in mind restrictions related to ``impossible measurements''. We illustrate our approach with three applications: a spacelikeness detector for causal-structure sensing, counting particle-creation densities in a supercritical potential and non-destructive discrimination between entangled states of the field and mixtures.
↳ quant-phhep-phhep-th0 citations
33
A First Bound on the Moffat Energy and Thorium-229 Clock as a Probe of the Nonlocal Time-Energy Structure and a Proposed Experiment for the use of Nuclear Entanglement and Squeezed States to Test Nonlocal Quantum Field Theory
E. J. Thompson🇨🇦 · Arvin Kouroshnia🇨🇦 · J. W. Moffat🇨🇦 · C. Chyrak🇨🇦 · G. Gervais🇨🇦 · H. A. Carteret🇨🇦
In this paper we derive the nonlocal Time-Energy uncertainty principle and then apply the published $^{229}$ Th nuclear clock data as a first probe of the nonlocality scale $E_M$. By using the direct clock-energy channel, we find conservative lower bounds on $E_M$ at the tens of MeV scale, with optimistic present-data estimates reaching the hundred MeV scale. Including the known nuclear sensitivity enhancement of the $^{229}$ Th transition gives us stronger model dependent bounds in the GeV range, while nuclear-scale reference-energy scenarios can reach the TeV range. The conclusion we draw from this is that nuclear clocks already provide an experimental route from nonlocal time--energy uncertainty to measurable laboratory bounds on non-Planckian nonlocality. We explore the idea of using a squeezed-state experiment with the $^{229} Th$ nuclear clock to test the time--energy structure of nonlocal quantum field theory. The idea is reasonably obtainable within the near future of nuclear clock experiments. One would prepare an ensemble of thorium nuclei in a coherent superposition of the nuclear ground state and the low-lying isomeric clock state, entangle the participating nuclei through a collective interaction, and generate a family of spin-squeezed states with a tunable squeezing parameter $r$ . Then a phase-controlled analysis pulse will rotate the selected collective nuclear quadrature into a measurable ground-isomer population difference. Near a strongly polarized collective state the normalized operators $J_{y} / S$ and $J_{z} / S$ obey the same approximate canonical algebra as the phase and amplitude quadratures of a squeezed optical mode. We use this experiment to either probe or bound the nonlocal energy scale $E_{M}$ .
↳ quant-phhep-exhep-phhep-th+11 citation
34
Dissecting the Scalar Cosmological Collider with the Cosmic Microwave Background
Oliver H. E. Philcox🇺🇸
The cosmological collider program probes ultra-high-energy physics by searching for subtle oscillatory signatures induced by inflationary particle exchange. Due to the non-linear symmetries usually assumed in inflation, these signals do not appear in isolation; moreover, their amplitudes are bounded by perturbativity and unitarity. To comprehensively probe cosmological collider physics, we must jointly analyze the full multi-field inflationary Lagrangian: in this work, we conduct such a study, probing single, double, and triple scalar field exchange and self-interactions across a wide range of masses (in both the complementary and principal series), mixings, and sound-speeds. Using modern theoretical tools (including the cosmological bootstrap and the cosmological flow), we construct a vast library of tree-level primordial bispectra: combining these with recent measurements of the inflationary shape function from Planck and modern sampling techniques, we perform Bayesian exploration of the eight-parameter multi-field likelihood. Most previous studies of cosmological collider physics assume weak mixing, such that the coupling between the scalar field and the Goldstone mode can be treated perturbatively: in our companion study, we demonstrate that this assumption is incompatible with current datasets except at the smallest masses. By solving for the inflationary bispectra numerically using CosmoFlow, we perform the first analysis of the strongly-mixed collider, demonstrating that the Planck constraints are much tighter than the theoretical bounds, though the oscillatory contributions are heavily suppressed. Across the full multi-field landscape, we find no evidence for new physics with a maximal $χ^{2}$ improvement of $5.3$ .
↳ astro-ph.COgr-qchep-exhep-ph+12 citations
35
Probing large mass-splitting inelastic Dark Matter with RES-NOVA
D. Alloni🇮🇹 · G. Benato🇮🇹 · P. Carniti🇮🇹 · M. Cataldo🇮🇹 · L. Chen🇨🇳 · M. Clemenza🇮🇹 · M. Consonni🇮🇹 · G. Croci🇮🇹 · I. Dafinei🇮🇹 · F.A. Danevich🇺🇦 · C. de Vecchi🇮🇹 · D. Di Martino🇮🇹 and 37 other authors
Probing inelastic dark matter at large mass splittings requires heavy target nuclei, an extended recoil-energy range, and the high-velocity tail of the dark-matter distribution. We exploit these features with the RES-NOVA prototype detector, featuring a PbWO4 cryogenic calorimeter, produced from archaeological Pb and operated at the deep-underground laboratory of Gran Sasso of INFN (Italy), analyzing a 32.4 g day exposure over 2.5 keV - 1 MeV under both the Standard Halo Model (SHM) and a Large Magellanic Cloud (LMC)-motivated velocity distribution. We extend direct-detection constraints beyond the 330 keV reach of established technologies (e.g. Xe-based TPCs), probing splittings up to 510 (780) keV in the SHM (LMC) benchmark, while future exposures will probe new regions of the parameter space.
↳ astro-ph.COhep-exhep-phphysics.ins-det6 citations
36
GUEST: Gravitational Universe Exploration with Satellite Tracking. A passive satellite laser-ranging mission for the dark gravitational Universe
Diego Blas🇪🇸 · Aurélien Hees🇫🇷 · F. Javier Atapuerca · Giada Bargiacchi · Massimo Bassan · Joshua N. Benabou🇺🇸 · Bruno Bertrand · Adrien Bourgoin🇫🇷 · Clare Burrage🇬🇧 · Nicolò Burzillà · Alfonso Caldiero · Roberto Campagnola and 69 other authors
GUEST is a space mission concept whose central objective is the detection of gravitational waves (GWs) in the microhertz band -- a physics-rich frequency window that no other present or planned detector can reach at a significant level. The concept is simple: two dense, passive spheres, covered with cube-corner retroreflectors, deployed in {highly eccentric} Earth orbits ( $e ≳ 0.7$ , period $P ≳ 33$ h), tracked continuously by the global network of satellite laser-ranging stations over a minimum observation time of 10 years, with an expected total duration of 30 years. The orbits themselves act as resonant detectors of the oscillating gravitational perturbations, with the microhertz sensitivity emerging from the selected orbital parameters. From the same data stream, GUEST delivers a programme of fundamental and applied science that cuts across particle physics, gravitational-wave astronomy, cosmology, astrophysics, and geodesy: the first coherent search for GWs from supermassive black-hole binaries in the $μ$ Hz band, the exploration of primordial GW backgrounds in the unexplored energy-scale gap between pulsar-timing arrays and LISA, a dedicated probe of ultra-light dark matter in a parameter region untouched by any other experiment, a new way to search for ultra-light bosons, order-of-magnitude-improved tests of new gravitational interactions at astronomical ranges, and a step change in the absolute determination of $G M_{\oplus}$ that underpins the Global Geodetic Observing System and future navigation and Earth-observation missions. This white paper presents the motivation, scientific reach, and mission concept of GUEST.
↳ astro-ph.COgr-qchep-phphysics.ins-det4 citations
37
Hawking emission of massive vector fields by Kerr black holes
Marco Calzà🇮🇹 · Miguel Faria🇵🇹 · Yuber F. Perez-Gonzalez🇪🇸 · João G. Rosa🇵🇹
We compute, for the first time, the Hawking emission spectrum of massive vector (Proca) fields by spinning Kerr black holes, determining the associated greybody factors and the resulting mass and spin loss functions. We show, in particular, that the scalar (longitudinal) polarization of the Proca field has a spectrum approaching that of a free scalar field in the massless limit (in which it becomes a pure gauge mode), although we find substantial differences for finite mass. The contribution of the two vector (transverse) polarization modes coincides, as expected, with the one obtained by Page for the Maxwell field in the massless limit. The black hole's evaporation rate is dominated by the scalar mode for slowly spinning black holes and by the two vector modes as the black hole approaches extremality. As for other fields, we find that Proca Hawking emission is Boltzmann-suppressed for Hawking temperatures $T_{H} ≲ ∣ μ - Ω_{H} ∣$ , where $μ$ is the field mass and $Ω_{H}$ is the angular velocity of the black hole's horizon. This implies that highly spinning black holes can efficiently emit massive vector fields at temperatures parametrically below the field's mass. Finally, we also find that superradiant emission is more pronounced for massive vector fields, with a maximum amplification factor of $≃ 7%$ (compared to $≃ 4%$ for massless photons).
↳ gr-qcastro-ph.COhep-ph0 citations
38
Quantum critical fan and emergent relativistic symmetry of two-dimensional Dirac semimetals
Friederike Ihssen🇩🇪 · Bilal Hawashin · Mireia Tolosa-Simeón🇩🇪 · Michael M. Scherer🇧🇷
Two-dimensional Dirac semimetals near a quantum critical point can be described by Gross--Neveu--Yukawa models. In view of recent experimental advances exhibiting a transition from Dirac semimetal to insulator in highly-tunable van-der-Waals heterostructures, a better understanding of finite-temperature effects is mandatory. Here, we study the Gross--Neveu--Yukawa phase diagram of the chiral Ising model with a non-perturbative field-theory approach at zero and finite temperature, both in the semimetallic phase and in the insulating phase with spontaneously broken $Z_{2}$ symmetry. At zero temperature, we find a quantum critical point with critical exponents that are close to the ones of the chiral Ising universality class, and show that relativistic symmetry is emergent close to the quantum critical point. At finite temperature, the ordered phase survives up to a finite critical temperature, at which we observe a classical phase transition into the disordered phase. We confirm that this transition lies in the two-dimensional Ising universality class. Finally, we determine the extent and scaling properties of the quantum critical fan, and the behavior of the quasiparticle weight, therein. In summary, we present a unified field-theoretical framework for the phase diagram of the chiral Ising model in the surroundings of its quantum critical point.
↳ cond-mat.str-elcond-mat.stat-mechhep-ph0 citations
39
The fermion sector of the SMEFT from asymptotically safe gravity
Astrid Eichhorn🇩🇪 · Moritz Gessner🇩🇪 · Shouryya Ray🇩🇰
Quantum gravity impacts Standard Model fields through effective interactions generated by renormalization. These appear as Standard Model Effective Field Theory (SMEFT) operators, where the effects of new physics are parametrized by the values of the higher-order SMEFT coefficients. As a step towards predicting these SMEFT coefficients from the asymptotically safe Standard Model with quantum gravity, we investigate the flow of a representative set of four-fermion operators under gravitational fluctuations. We strengthen the evidence for the near-perturbative nature of asymptotic safety by finding that these dimension-six-interactions remain irrelevant, resulting in the prediction of specific values for the dimensionless ratios of SMEFT coefficients in the IR. We also find a mechanism that can make a specific subset of these operators relevant. This subset is determined by symmetry considerations. On this basis, we provide a categorization of dimension-six-SMEFT interactions into two categories. Interactions in the first category are predicted to be non-zero, but Planck-scale suppressed. Interactions in the second category are predicted to be zero at small gravitational coupling, but may become free parameters of the theory at larger gravitational couplings.
↳ hep-thgr-qchep-ph0 citations
40
Extreme mass-ratio inspirals into Newtonian Proca stars
João Bernardo Silva🇵🇹 · Richard Brito🇵🇹
Massive bosonic fields can form self-gravitating solitonic structures, which for vector fields are known as Proca stars. For ultralight fields, these structures can describe the cores of dark matter haloes surrounding the supermassive black holes at the center of galaxies. It has been argued that future gravitational-wave detectors might be able to probe the properties of dark matter structures. However, most of the analyses considering ultralight dark matter have focused on massive scalar fields. In this work, we study how Proca stars respond to a perturbing small object inspiralling in their interior, in the Newtonian limit. We consider both Newtonian spherically symmetric Proca stars and the non-spherically symmetric ground-state solutions. We compute the total energy lost by the orbiting object and compare it to the case where the bosonic star is composed of a scalar field. Our results show that, at the Newtonian level, the energy lost by the object in a Proca star ground state is similar to that in its scalar field counterpart, with relative differences of at most $\sim 20%$ , while the maximum orbital energy loss rate in the ground-state configuration can be one to two orders of magnitude larger than in the spherically symmetric Proca star, when a central parasitic black hole is present. Our work motivates the need to study extreme mass-ratio inspirals into Proca stars using a fully relativistic setup, where differences between the Proca and scalar boson star ground states are expected to become more significant.
↳ gr-qchep-ph0 citations
41
Global Asymptotics, the Swampland Conjectures, and Preheating of String Moduli
Leia Price🇺🇸 · Kuver Sinha🇺🇸 · Robert Wiley Deal🇺🇸
While the cosmological implications of the Swampland Conjectures are usually discussed in the context of inflationary model building, they also have implications for the violent, non-adiabatic dynamics that can follow inflation or any displacement of string moduli. We study this question through the lens of self-resonant preheating, where we point out that two Swampland motivated structures play central roles. The first is the local curvature of the potential: the tachyonic branch of the refined de Sitter Conjecture singles out the kind of negative curvature that can drive tachyonic amplification. We show, however, that local curvature data is not enough; the large field asymptotics of the potential determines how the modulus samples the unstable region. Thus, plateaus, barriers, and runaways can lead to different resonance efficiencies; we study tachyonic resonance for bulk moduli in LVS and KKLT compactifications, as well as for typical blow-up moduli potentials and alpha-attractor models. The second Swampland motivated structure pertains to the tower of light states predicted by the Swampland Distance Conjecture. Modeling a finite subset of such states as an effective stochastic environment within which a string modulus preheats, we find that the light states mainly reshape existing resonance bands by smearing, shifting, and mildly seeding instabilities, rather than opening a robust new reheating channel. Our results suggest that Swampland physics affects preheating by controlling both the deterministic curvature structure of the potential as well as stochastic corrections from emergent light states.
↳ hep-thhep-ph1 citation
42
Ultra-peripheral Collisions
Jesus Guillermo Contreras🇨🇿 · Spencer Robert Klein🇺🇸
Photons in ultra-peripheral collisions of heavy ions (and protons) can be used for a variety of physics purposes - for studies of nuclear structure at low Bjorken $- x$ , as probes of beyond-standard-model physics at the highest possible photon energies, and to explore new regimes of quantum mechanics via interferometry between two photon sources that share no common origin. This review will present the origins of photons in ultra-peripheral collisions and discuss the important physics that is being done with these photons, with particular emphasis on those on the energy frontier for photon physics.
↳ hep-exhep-phnucl-exnucl-th0 citations
43
Time-Domain Axion Searches with Magnetic White Dwarfs
Hong-Yi Zhang🇨🇳 · Heng Bian🇨🇳 · Zhao-Yu Zuo🇨🇳
Magnetic white dwarfs can convert photons into axions in their strong magnetic fields, with the conversion probability modulating the light curve as the star rotates. However, this observable is degenerate with intrinsic stellar variability if the background is modeled too simplistically. We develop a controlled background-degeneracy framework that computes the axion-induced modulation from reconstructed stellar magnetic fields while fitting it simultaneously with a flexible Fourier model of the intrinsic light curve. Applying this framework to TESS observations of PG~1015+014 using two independent magnetic field reconstructions, we find that a sinusoidal stellar background can produce an apparent preference for nonzero axion-photon conversion. This preference is absorbed once the background light curve includes the second harmonic, indicating that higher-harmonic stellar variability is a leading degeneracy for precise photometric axion searches in magnetic white dwarfs. Interpreting the two-harmonic fit as a conservative baseline, we obtain competitive constraints for sub- $μ eV$ axions. We further derive an analytic target-ranking estimate for other TESS magnetic white dwarfs, identifying systems where phase-resolved magnetic modeling would be most valuable for competitive axion probes.
↳ astro-ph.HEhep-ph0 citations
44
Universal scaling between magnetar field and initial spin period for short gamma ray bursts
Qin-Mei Li🇨🇳 · Qi-Bin Sun🇨🇳 · Sheng-Bang Qian🇨🇳 · Li-Yin Zhu · Fu-Xing Li🇨🇳 · Si-Yuan Zhu🇨🇳 · Ming Lian🇨🇳 · Jing Li🇨🇳
The $B_{p}$ -- $P_{0}$ correlation serves as a critical probe of magnetar engine physics. Although this scaling relation has been firmly established for long gamma-ray bursts (lGRBs), systematic investigations for short GRBs (sGRBs) remain absent, leaving the physical differences between the two populations poorly constrained. Here we analyze 33 Swift sGRBs exhibiting prominent X-ray plateaus from newborn millisecond magnetar spin-down, and derive their initial spin period $P_{0}$ and polar magnetic field $B_{p}$ . sGRB magnetars span $P_{0} \in [1.73, 18.28] ms$ and $B_{p} \in [0.06, 2.82] \times 1 0^{17} G$ ( $⟨ B_{p} ⟩ = 7.05 \times 1 0^{16} G$ ), significantly more magnetized than lGRB magnetars ( $B_{p} \in [0.39, 23.08] \times 1 0^{15} G$ ; $⟨ B_{p} ⟩ = 3.69 \times 1 0^{15} G$ ). For the first time, we derive consistent power-law $B_{p}$ -- $P_{0}$ correlations for GRBs : the scaling for sGRBs is $lo g B_{p} = (0.84 \pm 0.07) lo g P_{0} + (15.79 \pm 0.07)$ , whose slope is highly consistent with that of lGRBs, $lo g B_{p} = (0.83 \pm 0.09) lo g P_{0} + (14.92 \pm 0.06)$ . The near-identical slopes imply a universal magnetar spin-down mechanism, while the vertical offset between intercepts traces divergent progenitor channels. This scaling relation thus offers a new diagnostic to disentangle the formation pathways of GRB. Within the framework of the standard spin-up model, the mass accretion rates of sGRBs ( $M ˙ \sim 1 \times 1 0^{- 1}$ to $3 \times 1 0^{- 1} M_{⊙} s^{- 1}$ ) are substantially higher than those of lGRBs ( $M ˙ \sim 1 0^{- 4}$ to $1 \times 1 0^{- 1} M_{⊙} s^{- 1}$ ). Our work completes the missing $B_{p}$ -- $P_{0}$ statistics for sGRBs, quantitatively unifies their magnetar physics with lGRBs, and provides new observational constraints on the origin diversity of relativistic transients.
↳ astro-ph.HEhep-ph0 citations
45
Nonlinear collective flow reveals the breakdown of quadrupole--hexadecapole scaling in heavy ion collisions
Hadi Mehrabpour🇨🇳 · Zahra Sheibani🇮🇷 · Li Yan🇨🇳 · Chunjian Zhang🇨🇳 · Abolfazl Mirjalili🇮🇷
Determining the role of intrinsic hexadecapole deformation ( $β_{4}$ ) in nuclear structure remains a long-standing challenge. Relativistic heavy-ion collisions provide a unique opportunity to address this problem by converting the initial nuclear geometry into the collective motion of the quark--gluon plasma (QGP). Using event-by-event viscous hydrodynamic simulations of ultra-central $^{238}$ U+ $^{238}$ U collisions at $s_{N N} = 193$ GeV, we investigate whether higher-order collective flow can isolate the contribution of $β_{4}$ and test the $β_{2} - β_{4}$ correlation. We demonstrate that information carried by the sign of $β_{4}$ survives the QGP evolution and is enhanced through nonlinear hydrodynamic response: the fourth-order flow harmonic acquires its topology dependence predominantly from the linear response, whereas the sensitivity of the sixth-order harmonic originates almost entirely from nonlinear mode coupling. As a consequence, the nonlinear response coefficient $ξ_{6, 222}$ cleanly separates the $(β_{2}, β_{4})$ intrinsic nuclear topologies. These results establish the sign of $β_{4}$ as an experimentally accessible signature of deviations from the quadrupole--hexadecapole correlation, demonstrating that higher-order collective flow provides a direct probe of nuclear multipole structure while revealing how nonlinear QGP dynamics encode subtle higher-order geometric information into final-state observables.
↳ nucl-thhep-exhep-phnucl-ex1 citation
46
A method for energy and radius reconstruction with simulated charge information in a ton-scale liquid scintillator detector like Taishan Antineutrino Observatory
Randhir Singh🇯🇵 · Yichen Li🇯🇵 · Xiaochuan Xie🇨🇳
Small neutrino detectors are a ton level detectors which can be placed very close to the core of Nuclear Power Plant. In some detectors liquid scintilling (LS) material is used as the detecting material. The antineutrinos from the reactor core fall on the liquid scintillator of the detector where they deposit energy via Inverse Beta Decay process (IBD). The energy absorbed by liquid scintillator is re-emitted in the form of scintillation. These photons then travel through the scintillating material and hit the Silicon Photo Multipliers (SiPMs) which are installed on the inner surface of detector's spherical copper shell. These SiPMs absorb the photons to give a charge output signal. The energy and radius reconstruction is done using the information of charge collected by the SiPMs. Due to factors like large photo-coverage with large photon detection efficiency, small spherical detector size and low temperature operation, small size LS detectors can achieve an unprecedented energy resolution. In this paper, we have used a template-dependent method exploiting simulated data to reconstruct the event radius and energy. This method uses response functions generated using radioactive source calibration data and the charge information to reconstruct the energy and the radius of the event by constructing maximizing a likelihood function. This methodology is applicable to all similar size spherical neutrino detector experiments.
↳ physics.ins-dethep-ph0 citations
47
Resolving the $T_{cc}^{+}$ with $π$ Exchange from Lattice QCD
Nelson Pitanga Lachini🇬🇧 · Raúl A. Briceño🇺🇸
We revisit the lattice QCD description of the doubly charmed tetraquark $T_{cc}^{+}$ using a finite-volume scattering formalism that incorporates one-pion exchange nonperturbatively, thereby making the nearest left-hand cut explicit while respecting unitarity and analyticity. We simultaneously determine the $D D^{⋆} π$ coupling and the isoscalar $D D^{⋆}$ scattering amplitude by reanalyzing the previously computed finite-volume $D D^{⋆}$ spectrum below the $D^{⋆} D^{⋆}$ threshold, on lattices with pion mass $m_{π} \approx 391 MeV$ . We find that the inclusion of pion exchange changes the $T_{cc}^{+}$ from a real-valued to a complex-valued pole in the second sheet of the $J^{P} = 1^{+}$ , $D D^{⋆}$ amplitude below threshold. We further predict that the $T_{cc}^{+}$ pole will move closer to the real-energy axis as the pion mass approaches its physical value.
↳ hep-lathep-phnucl-th3 citations
48
Quarkyonic Stars with Strangeness
Jin-Biao Hu🇳🇱 · Jun-Ting Ye🇨🇳 · Si-Pei Wang🇳🇱 · Rui Wang🇳🇱 · Zhen Zhang🇳🇱 · Lie-Wen Chen🇨🇳
We propose an extension of the quarkyonic matter framework that includes $u$ , $d$ , and $s$ quarks and the full baryon octet. Within this extended framework, we impose beta-equilibrium between baryons and leptons, while determining the quark fractions from the constituent quark contents of baryons. The hadronic sector of octet baryons is described by a recently developed density, momentum and isospin dependent effective interaction based on the N3LO Skyrme pseudopotential, whereas quarks and leptons are treated as free particles. We find that the quarkyonic mechanism can obviously reduce the critical density for hyperon appearance in neutron stars due to the fact that the nucleons are displaced to higher momentum states in quarkyonic matter and their chemical potentials rise accordingly. Furthermore, the quarkyonic mechanism can significantly stiffen the equation of state of hyperon star matter and thereby enhance the hyperon star maximum mass, thus helping to mitigate the hyperon puzzle.
↳ nucl-thastro-ph.HEhep-phnucl-ex0 citations
49
Towards anomaly detection searches for new physics signatures including Higgs bosons with weakly supervised machine learning
Chi Lung Cheng🇺🇸 · Julia Gonski🇺🇸 · Runze Li🇺🇸 · Qibin Liu🇺🇸 · Benjamin Nachman🇺🇸 · Dennis Noll🇺🇸 · Julie Khalilieh Romman🇺🇸 · Liangyu Wu🇺🇸
The Higgs boson, with its universal coupling to mass, provides a broadly applicable portal to sectors beyond the Standard Model and is therefore a natural anchor for anomaly detection (AD) at collider experiments. The Higgs And X Anomaly Detection (HAXAD) strategy offers a principled approach to searching for such anomalies occurring in association with a Higgs boson by combining machine-learning-based feature embedding, background estimation, and weakly supervised classification. This work extends the previous HAXAD approach towards the level of maturity required for application to recorded collider data. A major addition is the introduction and comparison of two new embedding strategies, which in turn shape the background estimation and classification. In addition, a new inference framework is developed, yielding signal-agnostic and signal-specific cross section limits and thereby completing the statistical machinery needed for future AD analyses built on HAXAD. The set of investigated signal models is also significantly expanded, allowing for the evaluation of sensitivity on a much broader phase space. Improvements to the method increase signal sensitivity with respect to the original method, and when benchmarked against an example cut-based search on the same final state, HAXAD matches or exceeds the best individual cut-based limits for a wide variety of considered signal models. These developments strengthen the case for HAXAD as a viable and compelling AD-based search strategy with novel discovery potential at colliders.
↳ hep-exhep-ph2 citations

Affiliations

first authorsco-authorsvia INSPIRE