HEP Phenomenology·hep-ph

Fri·Oct 16, 2026Friday·October 16, 2026

43 papers—31 primary·12 cross-listed

01
Technically Natural Baryogenesis with the QCD Axion
Pouya Asadi🇺🇸 · David Cyncynates🇺🇸 · Stefania Gori🇺🇸
The strong CP problem, dark matter, and the observed baryon abundance may all be connected dynamically through the QCD axion, though whether this connection is realized in Nature depends on additional degrees of freedom. We show that the required dynamics can arise from technically natural ingredients if multiple axions mix through the QCD anomaly. We review the connection between axion rotation and the baryon asymmetry, revisit the axiogenesis and kinetic-misalignment proposals, and derive new limits on their dynamics. Motivated by these considerations, naturalness and axion quality, we construct a realization in which mixing with additional axions both enhances the effective QCD axion field range through monodromy and dissipates excess rotational energy through mixing with a dark confining gauge sector, thereby avoiding overclosure. We study the resulting effective dynamics in several illustrative limits, uncovering phenomena that may arise more generally in multi-axion theories. We numerically evolve the full coupled system and show that it can simultaneously reproduce the observed baryon asymmetry and dark matter abundance within a predictive region of parameter space testable by near-future direct and indirect searches. Depending on the model parameters, either the QCD axion or the new heavy axion constitutes the dominant dark matter component. Successful baryogenesis favors a QCD axion decay constant near its current astrophysical lower bound, while the heavy axion lies within reach of forthcoming astrophysical and cosmological observations.
hep-ph0 citations
02
Leptogenesis with a GeV-Scale Quasi-Dirac Neutrino
Stephen F. King🇬🇧 · Soumen Kumar Manna🇮🇳 · Rishav Roshan🇬🇧 · Arunansu Sil🇮🇳
We discuss leptogenesis in a model with a GeV-scale quasi-Dirac neutral lepton, comprising mainly sterile states, which is accessible to future experiments. In particular, we show that Higgs-decay leptogenesis can naturally arise from the type-I seesaw mechanism with spontaneously broken global lepton number together with a discrete $Z_{2}$ symmetry, yielding two quasi-degenerate right-handed neutrinos (RHNs) which, to excellent approximation, form a single Dirac neutrino, with a tiny mass splitting as required for resonant enhancement generated by higher-dimensional lepton-number-violating operators. Incorporating finite-temperature effects, we show that the observed baryon asymmetry can be successfully generated through thermal Higgs decays for 0.1-10 GeV mass quasi-Dirac neutrinos, with the CP asymmetry arising from the interplay between the vacuum and thermal contributions to the mass splitting. In the parameter region of successful leptogenesis, the quasi-Dirac neutrino is accessible to future heavy neutral lepton searches at SHiP, MATHUSLA and FCC-ee. In addition, the same symmetry-breaking sector gives rise to unstable domain walls whose annihilation can generate a stochastic gravitational-wave background, providing a complementary probe of the framework.
hep-phastro-ph.CO0 citations
03
Auditing anapole dark matter: the limits of model independence in dark matter effective field theory
Duncan K. Adams🇺🇸 · Jared Barron🇺🇸 · Megan H. McDuffie🇺🇸
Effective field theory is a powerful tool for studying the low-energy behavior of dark sector models without explicit dependence on the high-energy physics. However, bottom-up EFT analyses can miss important processes in UV completions that are relevant for dark matter production and detection. In this work we demonstrate explicitly that for Majorana dark matter coupled to the photon by the dimension-six anapole operator, different UV completions make qualitatively different predictions at high energy colliders, in the early universe, and in direct detection experiments. Additionally, we show that competitive, and in some cases, leading constraints on anapole dark matter can be derived by searching for signatures of additional particles in the UV completion rather than direct probes of the DM itself. We argue that the UV completions studied in this work have categorically different phenomenologies and that `model-independent' EFT constraints are not always applicable.
hep-ph0 citations
04
Signatures of Leptophilic Baryogenesis at Muon Colliders
Hooman Davoudiasl🇺🇸 · Ian M. Lewis🇺🇸 · Miguel A. Soto Alcaraz🇺🇸
The baryon asymmetry of the Universe may be produced in a model with 3 Higgs fields, a Higgs Troika, without the need for a strong first order electroweak phase transition. The couplings of the new Higgs fields to Standard Model fermions are assumed in accord with the "Spontaneous Flavor Violation (SFV)" framework, in order to avoid large deviations from flavor physics constraints. We consider a leptophilic version of SFV and outline its potential signatures at future muon colliders, envisioned to be multi-TeV partonic center of momentum machines. Hence, they provide optimal venues to search for the leptophilic Higgs Troika baryogenesis mechanism. The projected reach for signals of the new scalars allows for probing the key components of the baryogenesis model at scales that accommodate cosmological requirements.
hep-ph0 citations
05
Collective Organization of String Fragmentation
Romuald A. Janik · Maciej A. Nowak · Marek M. Rams · Ismail Zahed
How coherent confining strings reorganize into hadronic matter is a central open problem in nonequilibrium gauge dynamics. Using real-time tensor-network simulations of the massive Schwinger model, we identify a collective organization underlying string fragmentation. For intermediate masses, the dynamics simplifies and more than $99%$ of the temporal evolution of the electric-field probability distribution is governed by a single collective mode whose decay tracks the survival probability of the parent string. The extracted survival law exhibits the same Gaussian dependence implied by the Lund world-sheet area law, providing microscopic support for its characteristic area law dependence without assuming the Lund fragmentation mechanism. The same mode controls the transition from the coherent string to the produced mesons, explains the universal non-thermal effective fluid equation of state, and essentially controls the growth of bipartite entanglement through the causal propagation of massive pairs. These results identify collective fragmentation as an organizing principle of coherent string breaking and provide a microscopic perspective on the dynamical origin of a central ingredient of Lund hadronization.
hep-phhep-thquant-ph0 citations
06
All three-loop four-point massless integrals with one off-shell leg
Thomas Gehrmann🇨🇭 · Petr Jakubčík🇨🇭 · Jungwon Lim🇩🇪 · Andreas von Manteuffel🇩🇪 · Cesare Carlo Mella🇬🇧 · Lorenzo Tancredi🇩🇪
We present the complete set of massless three-loop four-point master integrals with one off-shell external leg. These are essential building blocks for the three-loop virtual corrections to Higgs-boson or vector-boson production in association with a jet at the Large Hadron Collider, required for next-to-next-to-next-to-leading-order QCD predictions. We construct a complete basis of canonical integrals by identifying integrands with simple poles and unit leading singularities, solely by integrand analysis. This includes an integral family with 371 master integrals and a 19-dimensional top sector. The solutions for all relevant integrals are provided as a map to a minimal set of iterated integrals graded according to their analytic properties, together with high-precision series expansions.
hep-phhep-th0 citations
07
Machine-learning-based neutrino-event generation constrained by experimental measurements
Jose Luis Bonilla🇵🇱 · Krzysztof M. Graczyk🇵🇱 · Rwik Dharmapal Banerjee🇵🇱 · Beata E. Kowal🇵🇱 · Hemant Prasad🇵🇱 · Jan T. Sobczyk🇵🇱
We present a generative surrogate for charged-current $\nu_\mu$-nucleus scattering that can be calibrated to measured differential cross sections without event-level experimental samples. Starting from a theoretical interaction model, we fine-tune the surrogate to a MicroBooNE measurement and show that this also improves the description of observables not used in the fit. The calibrated model can also be applied to measurements from different neutrino fluxes without retuning, while retaining event-level predictions of outgoing-muon kinematics. Our results show that experimental cross sections can directly constrain generative event models while preserving their applicability across different observables and beam configurations.
hep-phcs.LGhep-exnucl-ex+10 citations
08
CT25: the new generation of CTEQ-TEA PDFs
Alim Ablat🇨🇳 · Daniel Adamiak🇺🇸 · Aurore Courtoy🇲🇽 · Sayipjamal Dulat🇨🇳 · Yao Fu · Marco Guzzi🇺🇸 · T. J. Hobbs🇺🇸 · Joey Huston🇺🇸 · Maximiliano Ponce Chavez · Kirtimaan Mohan🇺🇸 · Pavel Nadolsky🇺🇸 · Tanishq Sharma🇮🇹 and 3 other authors
This contribution reviews CT25, a new generation of CTEQ--TEA parton distribution functions (PDFs) for precision QCD. With its first member sets released in 2025, the CT25 family addresses common uses of parton distributions in diverse contexts. We describe the CTEQ--TEA Parton Cloud, an online database of exploratory global fits to precision QCD measurements, from which we select PDF solutions for general- and special-purpose calculations. These solutions are published as complementary error PDF ensembles---the baseline CT25, CT25m, CT25pd, and ensembles with conservative priors---optimized for distinct uses. They implement new approaches to quantifying uncertainties and different treatments of theoretical, parametrization, and nuclear-target uncertainties. In particular, they provide complementary frameworks for exploring PDF uncertainties at large partonic momentum fractions relevant to HL-LHC and EIC studies. Further details will appear in the forthcoming CT25 publication.
hep-ph0 citations
09
Bounds on hadronic contributions to the anomalous magnetic moment of the $τ$ lepton from QCD Sum Rules
Siyuan Li🇩🇪 · J. Ho🇺🇸 · R.T. Kleiv🇨🇦 · D. Leighton🇨🇦 · E.J. Obbink🇺🇸 · T.G. Steele🇨🇦
A QCD sum-rule study is performed to place bounds on the leading-order (LO) hadronic vacuum polarization (HVP) contribution to the anomalous magnetic moment of the $τ$ lepton ( $a_{τ}^{HVP, LO}, a_{τ} = (g - 2)_{τ} /2$ ). The QCD contributions to $a_{τ}^{HVP, LO}$ are modeled as a combination of Laplace QCD sum rules (LSRs) and finite-energy QCD sum rules (FESRs) of various weights, which are bounded by Hölder and related fundamental inequalities. The light-quark ( $u, d, s$ ) contributions are evaluated up to five-loop order in perturbative contributions in the chiral limit, LO in light quark mass corrections, next-to-leading order (NLO) in dimension-four QCD condensates and to LO in dimension-six QCD condensates. Extending previous work on $a_{μ}^{HVP, LO}$ , we present a robust methodology for using QCD sum rules to constrain $a_{τ}^{HVP, LO}$ , and more generally any lepton $g - 2$ . A criterion is developed to extract from the bounds analysis a final result of $a_{τ}^{QCD} = (3.385 \pm 0.048) \times 1 0^{- 6}$ , which after inclusion of charmonium and bottomonium contributions gives a final result $a_{τ}^{HVP, LO} = (3.501 \pm 0.048) \times 1 0^{- 6}$ , comparable to data-driven and lattice predictions. Lattice QCD results along with our value for $a_{τ}^{HVP, LO}$ are used to obtain a combined QCD determination from lattice and sum-rule methods of $a_{μ}^{HVP, LO} = (7.217 \pm 0.233) \times 1 0^{- 8}$ . Our analysis provides fundamental QCD sum-rule inputs into the theoretical determinations of $a_{τ}$ , and establishes new methodologies for QCD sum-rule determinations of low-energy observables.
hep-ph0 citations
10
The Sill distribution for all partial waves
Krzysztof Kyzioł🇵🇱 · Francesco Giacosa🇵🇱
In high-energy physics, short-lived resonances appearing in scattering processes are described by energy-dependent spectral functions. The relativistic Breit--Wigner distribution (rBW), obtained as a relativistic extension of the standard Breit--Wigner form, is commonly employed owing to its simplicity. However, when the lower-energy threshold lies sufficiently close to the resonance peak, sizable deviations from the rBW line shape are expected. The Sill distribution provides a simple way to incorporate the physical threshold while preserving exact normalization, but in its original formulation it is inherently restricted to $s$ -wave decays. Here, we extend the Sill distribution to arbitrary partial waves. The correct $ℓ$ -wave threshold behaviour is implemented while exact normalization is retained through a simple modification of the mass term of the propagator. As a benchmark, the $p$ -wave Sill provides a very good description of the $Δ (1232)^{++}$ line shape up to 1.35 GeV and simultaneously reproduces its on-shell mass and width and its complex pole position, in agreement with independent determinations compiled by the PDG.
hep-phhep-exnucl-th0 citations
11
Testing the inelastic dark matter interpretation of the LZ event with heavy-element experiments
Peter W. Graham · Juan P. Luengas · Harikrishnan Ramani · Samuel S. Y. Wong
We consider the inelastic dark matter interpretation of the recent 248 keV event observed by LZ and identify different experiments that could test it. Details of the underlying model and the ability of complementary experiments to test it depend significantly on the high-velocity tail of the dark matter distribution. We consider several example velocity distributions motivated by the impact of the Large Magellanic Cloud (LMC) in order to map out the effects of this dependence. For example, we illustrate the type of high-velocity tail that would make the thermal Higgsino viable despite stringent constraints from solar neutrinos: Reducing the flux of the tail relative to simulation results improves the Higgsino fit, while extending the tail to higher velocities at fluxes below current simulation resolution evades the solar neutrino bound. This motivates more detailed simulations at higher resolution to understand the tail better. Even if xenon experiments confirm the signal event, complementary experiments are still required to test whether the underlying model is inelastic dark matter and to break degeneracies in the measurement of dark matter parameters such as mass and mass splitting. Heavy-element paleodetectors could cover most of the parameter space relevant to the LZ event. Their use of different elements could determine the dark matter mass and splitting, while their unique sensitivity to the history of the dark matter distribution could test the signal's LMC origin. Luminous detection in large neutrino detectors with heavy-element supplements could directly test the inelastic nature of the signal and measure the mass splitting, while its sensitivity to the radiative decay rate could provide strong evidence for the Higgsino interpretation.
hep-phastro-ph.COastro-ph.GAhep-ex
12
Two-loop HTL-resummed thermodynamics for pure $N = 2$ supersymmetric Yang-Mills theory
Qianqian Du · Bingxiang Luo · Ubaid Tantary
We compute the two-loop hard-thermal-loop (HTL) resummed thermodynamic potential of pure four-dimensional $N = 2$ supersymmetric Yang-Mills theory using regularization by dimensional reduction. Our result is gauge invariant and was renormalized using vacuum energy, gluon mass $m_{d}$ and quark mass $m_{q}$ counterterms. The thermal mass parameters are determined self-consistently and numerically from gap equations incorporating the running coupling. Based on these solutions, we numerically calculate the scaled pressure, entropy density, energy density, and trace anomaly and compare them with the results in the static perturbative limit through $O (λ^{2})$ . For the first three quantities, next-to-leading-order (NLO) corrections are positive and have discernible effects at small coupling, and reduce the renormalization-scale dependence at relatively large couplings. We assess $m_{q}$ -prescription dependence by comparing these results with those obtained by setting $m_{q} = 0$ . We find that it has a substantial impact on $m_{d}$ and the scalar mass $m_{s}$ at large couplings, and it reverses the signs of the NLO corrections to the first three quantities and qualitatively alters the trace anomaly.
hep-ph
13
PTagent: An LLM-assisted tool for finite-temperature model construction in cosmological phase transitions
Lei Wu · Yang Xiao · Jin Min Yang · Yang Zhang
Cosmological phase-transition calculations require well-defined finite-temperature numerical models, whose construction involves assembling model information under consistent theoretical prescriptions. In this work we present \texttt{PTagent}, a large language model (LLM) agent-based framework for constructing such models from SARAH model files, research papers, and DRalgo sources. The LLM agent interprets and organizes model information and identifies unresolved physical choices, while dedicated backends perform the model-dependent calculations. After review and approval of the resulting physical model specification, the backends generate the corresponding CosmoTransitions-style or PhaseTracer-style numerical potentials. By separating model interpretation from numerical implementation, PTagent provides an inspectable and reproducible approach to finite-temperature model construction for cosmological phase-transition studies.
hep-ph
14
Two-variable longitudinal distribution of the $Λ_{b}$ in a three-quark light-front model
Shuai Xu · Xiao-Nan Li
We determine a normalized two-variable longitudinal distribution of the $Λ_{b} = (u d) b$ baryon from a covariant three-quark light-front wave function. The scalar $u d$ channel is selected with the good-component structure $C γ_{5} γ^{+}$ , and the two independent transverse momenta are integrated without introducing an elementary diquark. The resulting model-scale valence distribution, $Ψ_{2}^{LF} (x_{u}, x_{d})$ , retains both the heavy--light and internal-light momentum scales of the parent wave function. It is symmetric under $x_{u} \leftrightarrow x_{d}$ , is concentrated where both light-quark fractions are small, and separates the total light-pair momentum from its internal sharing. For the central parameter set we find $⟨ x_{u} ⟩ = ⟨ x_{d} ⟩ = 0.130$ , $⟨ x_{b} ⟩ = 0.739$ , $⟨ ζ^{2} ⟩ = 0.153$ , and $⟨ ζ^{4} ⟩ = 0.055$ , where $ζ = (x_{u} - x_{d}) / (x_{u} + x_{d})$ . Parameter variations give $⟨ x_{u} ⟩ = 0.13 0_{- 0.007}^{+ 0.007}$ , $⟨ x_{b} ⟩ = 0.73 9_{- 0.014}^{+ 0.014}$ , $⟨ ζ^{2} ⟩ = 0.15 3_{- 0.016}^{+ 0.014}$ , and $⟨ ζ^{4} ⟩ = 0.05 5_{- 0.009}^{+ 0.009}$ . The heavy--light momentum partition is controlled mainly by $β_{b, u d}$ and $m_{b}$ , whereas the internal $u$ -- $d$ sharing is most sensitive to $β_{u d}$ . The result provides a compact finite-mass benchmark for three-quark longitudinal structure, with distinct observables for heavy--light momentum sharing and correlations inside the light pair.
hep-ph
15
Nonleptonic decays of the double-charmed baryon $Ξ_{cc}^{+}$ with dynamically determined baryon wave functions
Yu-Shuai Li · Hong-Tao An
Motivated by the recent observation of the double-charmed baryon $Ξ_{cc}^{+}$ by the LHCb Collaboration, we systematically investigate the two-body nonleptonic decays of the $Ξ_{cc}^{+}$ into a single-charmed baryon and a light pseudoscalar meson. In our calculation, both factorizable and nonfactorizable decay amplitudes are evaluated within the framework of nonrelativistic quark model combined with the baryon wave functions dynamically determined by numerically solving the three-body Schrödinger equation with a nonrelativistic potential model. In particular, the nonfactorizable $W$ -exchange amplitudes are estimated under pole model by considering $J^{P} = 1/ 2^{\pm}$ low-lying intermediate charmed-baryon poles, and our results show that these contributions are comparable to or even dominate the factorizable amplitudes in several decay channels. Moreover, assuming a lifetime of $τ_{Ξ_{cc}^{+}} = 47 fs$ , we predict relatively large branching fractions for several CF decays, including $B (Ξ_{cc}^{+} \to Ξ_{c}^{'0} π^{+}) = 8.90%$ , $B (Ξ_{cc}^{+} \to Ω_{c}^{0} K^{+}) = 7.09%$ , $B (Ξ_{cc}^{+} \to Σ_{c}^{+} K ˉ^{0}) = 6.92%$ , $B (Ξ_{cc}^{+} \to Ξ_{c}^{+} π^{0}) = 5.28%$ , and $B (Ξ_{cc}^{+} \to Σ_{c}^{++} K^{-}) = 5.17%$ . These channels are promising candidates for future experimental searches at the LHCb.
hep-ph
16
Determining the Threshold Excess in Top-Quark Pair Production through a Global PDF Analysis
Richard D. Ball · Jaco ter Hoeve
We present an empirical determination of the threshold excess $Δ$ in top-quark pair production, taking full account of correlated uncertainties with PDFs, the top-quark mass $m_{t}$ and the strong coupling $α_{s} (m_{Z})$ . We extract $Δ$ from a variety of differential $t t ˉ$ cross-section measurements by ATLAS and CMS at 8 and 13 TeV, using theoretical predictions of the $t t ˉ$ continuum up to NNLO QCD accuracy, including an estimate of missing higher order uncertainties and NLO EW corrections. At 8 TeV we see no evidence of a significant threshold excess, but at 13 TeV obtain results above the NNLO QCD $t t ˉ$ background at just over two $σ$ when we combine all the available measurements. We also find evidence of a strong correlation between $Δ$ and $m_{t}$ , which must be taken into account if the uncertainty on any threshold excess is to be estimated reliably.
hep-ph
17
Revisiting $B_{c}^{(*)}$ production in $Z$ -boson decays at NLO in QCD
Qi-Wei Ke · Lei Guo · Jun Zeng · Xu-Chang Zheng
We study $B_{c}^{(*)}$ production in $Z$ -boson decays at next-to-leading order (NLO) in QCD within the color-singlet nonrelativistic QCD framework. The analysis covers both the $1 S$ and $2 S$ pseudoscalar and vector states, extending the phenomenological study to radially excited $B_{c}$ mesons. We calculate direct production widths and energy-fraction and invariant-mass distributions, including both charm- and bottom-quark production topologies. For the central inputs and $μ_{R} = 2 m_{b}$ , the $K$ factors are $1.52$ for $B_{c}$ and $1.33$ for $B_{c}^{*}$ . We examine uncertainties from the renormalization scale, heavy-quark masses, and wave functions at the origin, and apply the principle of maximum conformality to fix the renormalization scale from the $β_{0}$ -dependent NLO contribution. The NLO corrections enhance the small- and intermediate-energy-fraction regions and modify the invariant-mass spectra. We discuss these features in relation to heavy-quark fragmentation. The results provide production-rate and kinematic inputs for studies of ground-state and radially excited $B_{c}$ mesons at high-statistics $Z$ factories.
hep-phhep-ex
18
Hidden-charm and hidden-beauty hybrid mesons
Raghavendra Kaushal · Bhaghyesh
The mass spectra of $Π_{u}$ , $Σ_{u}^{-}$ , $Π_{g}$ , $Δ_{g}$ , $Σ_{g}^{-}$ , $Δ_{u}$ , and $Σ_{u}^{+}$ hybrid charmonium and hybrid bottomonium states are computed using a non-relativistic potential model. The hybrid potential is modelled as a linear combination of quarkonium potential and gluonic excited potential. The gluonic excited potential is computed by fitting the potential difference between hybrid potential and quarkonium potential obtained from the lattice quantum chromodynamics. Experimental masses and $J^{P C}$ values of $Ψ (4230)$ , $Ψ (4500)$ , $X (4500)$ , and $Ψ (4660)$ are compatible with hybrid charmonium states, and $Υ (10753)$ and $Υ (11050)$ are compatible with hybrid bottomonium states obtained from our model, respectively.
hep-ph
19
Non-Invertible Froggatt-Nielsen Symmetry
Hajime Otsuka · Ryo Yokokura
We investigate non-invertible completions of anomalous flavor symmetries and their application to Dirac neutrino masses. We formulate symmetry defects dressed by topological quantum field theories for flavor symmetries including finite non-Abelian flavor transformations with rational anomaly characters and modular flavor symmetries with the rational part of modular anomaly cocycles, for gauge sectors with the required exact higher-form symmetry. As a concrete example, we construct a Froggatt-Nielsen (FN) model in which an order-four subgroup $Z_{4}^{FN} \subset U (1)_{FN}$ is completed into a non-invertible defect through its mixed anomaly with an intermediate hidden $U (1)_{H}$ gauge sector in the infrared monopole-decoupling limit. The non-invertible FN symmetry can be explicitly broken at the energy scale where monopoles become dynamical. This breaking from the infrared viewpoint can be realized in an ultraviolet hidden $S U (2)_{H}$ theory as instanton effects, where a constrained instanton with topological charge one generates a fermion mixing term that violates FN charge by one unit. Its coefficient contains the nonperturbative factor $ζ_{H} \sim exp [- 8 π^{2} / g_{H}^{2} (v_{H})]$ . When independent FN-breaking terms are subleading, integrating out the heavy fermions gives $(Y_{ν})_{ij} \propto ζ_{H} ϵ^{ℓ_{i} + n_{j}}$ in a rotated basis for the right-handed neutrinos, to leading order in the instanton-induced fermion mixing. The nonperturbative factor provides the exponential suppression of the neutrino Yukawa couplings, while the FN charges determine the powers of $ϵ$ . For the chosen FN charges and generic order-one coefficients, $m_{2} / m_{3} \sim ϵ$ , favoring normal ordering. An independent $Z_{8}^{D}$ gauge symmetry forbids Majorana masses. The same FN charge assignment reproduces the leading quark and charged-lepton Yukawa hierarchies.
hep-phhep-th
20
Nuclear PDFs
K. Greve · T. Ježo · M. Klasen · A. Kusina · F.I. Olness · J. Wissmann
We summarize the current status of global analyses of model-independent nuclear parton distri- bution functions (nPDFs). A carefully conducted global analysis of nPDFs in the era of heavy-ion collisions at the LHC is key to gaining access to new information through the data measured by the collider experiments. This implies incorporating as large and diverse a dataset as possible, as well as the latest theoretical calculations, in order to capture a faithful representation of nuclear structure that reflects the current state of knowledge. On the other hand, the uncertainties in par- ticular must reflect what is not known. For many observables, nuclear uncertainties represent the most significant source of error in current theoretical models; nevertheless, they should not, where possible, be artificially constrained (for example, through parameterization bias). The quality of a global (n)PDF fit is often measured by the $χ^{2}$ per degree of freedom, which is approximately one for a fit that describes the data precisely without overfitting. Many additional aspects allow to characterize a good fit, e.g. the $χ^{2}$ distribution per experiment, the shape of the uncertainties, and the sensitivity to different types of data. We inspect various fit quality indicators for fits obtained by different groups. Morever we pay close attention to the $A$ -dependence. Traditionally, the A-dependence had a primarily functional role in global nPDF analyses and comparatively less attention has been paid to it when characterizing a fit. However, we have now entered the era of nuclei collisions at the LHC and need to investigate the $A$ -dependence properly.
hep-phnucl-th
21
Multi-Higgs production from a theory of varying Higgs quartic and top Yukawa couplings
Ulf Danielsson · Rikard Enberg · Gunnar Ingelman · Soumyadip Kundu · Tanumoy Mandal · Subhadip Mitra
We study the collider phenomenology of a theory in which the Higgs quartic self-coupling and the top Yukawa coupling are \textit{varying couplings}, which arise dynamically from two scalar fields, $ϕ_{1}$ and $ϕ_{2}$ . Depending on the scalar masses relative to twice the top-quark mass, the heavy scalars decay mainly to Higgs boson pairs ( $hh$ ) or to top-quark pairs ( $t t ˉ$ ), giving two distinct signatures. We find sizeable cross sections for resonant $hh$ production, and also for the background-suppressed process with three Higgs bosons ( $hhh$ ) from associated production, $pp \to h ϕ_{i} \to hhh$ . By recasting ATLAS resonance searches, we set bounds on the effective new-physics scales $Λ_{1}$ and $Λ_{2}$ at the TeV scale. We also show that the High-Luminosity LHC (HL-LHC) will probe this parameter space further, through combined measurements of the $hh$ , $t t ˉ$ and multi-Higgs channels. This gives a strong, multi-channel test of whether the electroweak sector has a dynamical origin.
hep-phhep-th
22
Decay modeling in 4top production
Manal Alsairafi
We present NLO QCD predictions for the $pp \to t t ˉ t t ˉ + X$ process in the 4 lepton decay channel at the integrated and differential level for the LHC centre-of-mass energy of $s = 13.6$ ~TeV. Specifically, we compare the fixed order NLO QCD calculations to the parton-shower matched results obtained with \textsc{MC@NLO} and \textsc{Powheg} matching. In the former, NLO QCD corrections are consistently included in the production and decay of the four top quarks, preserving all spin correlations. In the latter, higher order effects in top-quark decays with approximate spin correlations are simulated in the parton showers, using Pythia. Additionally the impact of including matrix element corrections in the top quark decays in the parton-shower matched predictions is analysed.
hep-ph
23
From Non-Thermal to Thermal: Cosmological Imprints of Self-Interacting Secluded Dark Matter
Koushik Dutta · Deep Ghosh · Ahamadullah Khan
Dark matter (DM), secluded from the Standard Model (SM), can attain internal thermalization through self-interactions. We investigate the thermalization of a real scalar DM field with a quartic self-coupling, initially produced from the perturbative decay of the coherently oscillating inflaton field during reheating. The thermalization process has been studied numerically by solving Boltzmann equation of the DM momentum distribution function in presence of $2 \to 2$ DM elastic self-scatterings. In the absence of number-changing processes, the thermalized dark sector is characterized by a temperature and a nonzero chemical potential, determined by the inflaton mass and the reheat temperature. We find that if the inflaton mass is greater (smaller) than the reheat temperature, the DM temperature can be greater (smaller) than the SM temperature during Big Bang Nucleosynthesis, without violating any cosmological constraints. This is realized with a negative (positive) chemical potential for the DM temperature greater (smaller) than the SM one. Depending on DM production history, we can achieve the lower limit on the DM mass much below than in warm DM scenarios. The thermalization via self-scatterings tends to suppress the DM co-moving free-streaming length, compared to the non-thermal scenario without any collisions. Consequently, the lower limit on the DM mass weakens approximately by $40%$ for a suitable choice of quartic self-coupling than in the non-thermal scenario. We obtain the lower limits on the thermal DM mass to be $2.2 \times 1 0^{- 10}$ GeV and $0.47$ GeV for reheat temperatures, $5 \times 1 0^{6}$ GeV and $5$ MeV respectively, while the inflaton mass is set at $1 0^{3}$ GeV.
hep-phastro-ph.COgr-qc
24
Low-Scale See-Saw Mechanism and the Majorana Nature of Heavy Neutrinos
Takuya Okawa · S. T. Petcov
We investigate the possibility to determine the Majorana nature of the heavy Majorana neutrinos present in the low-scale type I seesaw mechanism of neutrino mass generation in experiments at $e^{+} - e^{-}$ and $μ^{+} - μ^{-}$ colliders. This is done on the examples of two specific symmetry-protected seesaw scenarios with two right-handed (RH) singlet neutrinos and one seesaw realization with three RH neutrinos. We use the forward-backward symmetry in the angular distribution of the heavy neutral leptons produced in the $e^{+} - e^{-}$ and $μ^{+} - μ^{-}$ collisions as an indicator of their Majorana nature. Our results indicate that the experiments at FCCee during its first phase of operation have a remarkable potential not only to discover the heavy neutral leptons associated with the type I seesaw mechanism if they have masses smaller than the $Z^{0}$ -boson mass, but also to probe and provide evidence for their Majorana nature.
hep-ph
25
Lossy Lorentz boosts at ultra-relativistic energies: Numerical study and source survey of high-energy physics software
Christian Bierlich
Most high-energy-physics software packages implement Lorentz boosts for themselves. At sufficiently large boosts, these routines can return finite, plausible-looking four-vectors whose invariant masses and rest-frame properties are no longer accurate. We survey implementations in widely used collider and air-shower software and compare representative algorithms in three numerical tests. We find that the main problem is usually information discarded by the representation, rather than the arithmetic of the boost formula. Information can be lost when a boost is specified only by its velocity, and again when the result is stored only through Cartesian components. Richer boost input prevents the first loss, while retaining light-cone coordinates prevents the second. Ordinary hard processes at present colliders are safe in double precision; the relevant regimes are low-mass systems, highly boosted auxiliary frames, single-precision particle records and air-shower simulations. Extreme scale hierarchies in parton-shower accuracy tests and ultra-heavy particle decays provide still more demanding cases.
hep-phphysics.comp-ph
26
Probing the Axion--Photon--Dark Photon Interaction with LHC Mono-Photons and Fermi-LAT Gamma-Ray Lines
Chuan-Ren Chen · Takaaki Nomura · Van Que Tran
We investigate the axion--photon--dark photon interaction at the LHC and in gamma-ray line searches. By recasting the CMS mono-photon data, we derive a $95%$ CL exclusion reaching $g_{a γ^{'} γ} ≃ 4.8 \times 1 0^{- 4} GeV^{- 1}$ for dark photon masses $m_{γ^{'}} ≲ 100$ GeV, with sensitivity extending to $m_{γ^{'}} ≃ 2.3$ TeV, where the effective theory approaches its validity limit. This improves upon the existing LEP mono-photon constraint by a factor of $3$ or more, depending on the dark photon mass. The projected HL-LHC sensitivity improves by a further factor of $\sim 2.7$ and extends the reach to $m_{γ^{'}} ≃ 3$ TeV. The same interaction also induces $s$ -wave annihilation of axions into $γ γ$ . If the axion constitutes dark matter, Fermi-LAT gamma-ray line data become more constraining than the LHC for $m_{a} ≳ 160$ GeV at $m_{γ^{'}} = 300$ GeV, where the on-shell collider signal is kinematically suppressed. Combining collider and gamma-ray line constraints excludes a thermal relic axion across the axion mass range considered for this benchmark.
hep-ph
27
Modified hydrogen recombination rate due to non-Hubble redshift effects
I.V Krasnov · N.S. Nedelko
The accumulation of observational data in recent years has led to a peculiar situation in which measurements of the cosmological parameters made by various collaborations and using different methods yield significantly different values. A solution to this problem may be found by modifying the models used to obtain these values. In this work, we revisit the standard approach to the recombination calculation and investigate a mechanism that can introduce corrections to the rate at which Lyman-alpha photons escape the resonance line. We find that interactions of Lyman-alpha line photons with moving neutral hydrogen atoms can become a source of such a correction. An analysis of CMB data for the modified model favors the existence of a non-Hubble redshift effect and prefers slightly higher values of $H_{0}$ and smaller values of $Ω_{m}$ and $S_{8}$ compared to the standard $Λ$ CDM model, as well as a smaller value of the scalar spectrum index $n_{s}$ .
hep-phastro-ph.COhep-th
28
DUNE Beam-Energy Dependence of Sensitivity to the Violation of the Equivalence Principle
Monjowara Khatun · Debajyoti Dutta
In this work, we investigate the dependence of DUNE's sensitivity to possible violations of the equivalence principle (VEP) on the beam-energy configuration, comparing the Low-Energy (LE) and Medium-Energy (ME) beams. We find that the LE configuration generally provides stronger constraints on the VEP parameters than the ME configuration. For $θ_{23} = 4 3^{\circ}$ , the LE configuration constrains $ΦΔ γ_{21}$ and $ΦΔ γ_{31}$ to $8.47 \times 1 0^{- 24}$ and $8.53 \times 1 0^{- 24}$ , respectively, at the $3 σ$ CL. The appearance channels shows stronger phase-dependency degeneracies while the disappearance channels exhibits smoother exclusion sensitivity. This work further confirms the advantage of the LE configuration over the ME, in constraining the correlated VEP parameter space. For the assumed true value of $θ_{23} = 4 3^{\circ}$ , The LE configuration restricts the VEP parameter space to $Φ Δ γ_{21} \in [- 8.47, 8.47] \times 1 0^{- 24}$ and $Φ Δ γ_{31} \in [- 8.53, 8.53] \times 1 0^{- 24}$ at $3 σ$ .We also find that neutrino-mode and antineutrino-mode running can independently probe VEP effects at DUNE, with the relative sensitivity depending on the beam-energy configuration. These results highlight the importance of beam-energy optimization and channel-wise analysis in exploring possible violations of the equivalence principle at DUNE.
hep-ph
29
Radiative transitions of hybrid mesons
Shahriyar Jafarzade · Eric S. Swanson
Radiative transitions of hybrid mesons probe nonperturbative gluodynamics, particularly the interplay between quark spin and gluonic excitations, and are of direct relevance to the search for exotic hadrons at Jefferson Lab. We calculate these transitions across the lowest charmonium-hybrid multiplet in a constituent gluon model based on Coulomb-gauge QCD in the heavy quark expansion. The results for $Y \to η_{c} γ$ and $Y \to χ_{c 0} γ$ overlap the width obtained in quenched lattice computations, whereas $η_{c 1} \to J / ψ γ$ is substantially below the corresponding lattice estimate.
hep-phhep-exhep-latnucl-th
30
Spurious Singularities in Dipole Subtraction Cross Sections and their Damping with Convergence Factors
Michael H. Seymour · Andrzej Siódmok · James Whitehead
In the dipole subtraction algorithm, the real-virtual cancellation in NLO calculations of arbitrary observables is implemented by defining a subtraction cross section that matches all of the singularities of the real emission cross section. The converse, however, is not true: the subtraction cross section contains additional singularities, coming from the underlying Born matrix element, that the real cross section does not. We call these spurious singularities. If used as originally proposed, this is not a problem, because the value of the observable damps these singularities, but in applications such as dipole showers and matching algorithms, it can lead to poor statistical convergence, or dependence on unphysical regulators such as technical or generation cuts. In this paper, we show that additional factors, which we call convergence factors, can be applied to the subtraction cross section to damp these spurious singularities and improve the convergence. We perform the required phase-space integrals to yield modified dipole insertion operators, and verify numerically that they indeed remove the logarithmic dependence on generation cuts that arises in their absence. This paper is dedicated to the memory of Stefano Catani, with whom the work was originally started.
hep-ph
31
From Axion Detection to Dark Matter Astronomy
Jae Hyeok Chang · Stefano Profumo
A global haloscope network could turn an axion discovery into astronomy of dark matter substructure and transients. We combine interferometric phase, spatial coherence, and spectroscopy to study the formation and evolution of axion substructure through measurements of flow directions and velocity distributions. For tidal streams, a four-site forecast shows how longitudinal and transverse velocity dispersions can be measured jointly. Interpreted with dynamical and population models, these measurements could test axion production scenarios. Extensions to miniclusters, axion stars, and emitted bursts would broaden the astrophysical reach of laboratory detection.
hep-phastro-ph.COhep-ex
32
Breaking de Sitter Symmetry with Cosmic Topology: Cosmological Role of Infrared Vacuum Freedom
Anna Negro🇺🇸 · Kurt Hinterbichler🇺🇸 · Glenn D. Starkman🇺🇸 · Yashar Akrami🇺🇸 · Stefano Anselmi🇮🇹 · Javier Carrón Duque🇪🇸 · Mikel Martin Barandiaran🇪🇸 · Andrius Tamosiunas🇳🇴
When spatial sections of spacetime are topologically nontrivial, the symmetry arguments usually used to choose the Bunch-Davies vacuum are no longer guaranteed to apply. We study this problem for a scalar field on de Sitter spacetime with toroidal spatial sections. The Hadamard conditions, which ensure the same short-distance structure as in flat space, are local and naturally insensitive to the compactification. By contrast, we find that the infrared sector is affected by the toroidal identifications that break global de Sitter invariance, thereby removing the usual argument for discarding zero-mode contributions. We treat the remaining zero-mode freedom as an effective topology-induced source and analyze its effects on an inflationary de Sitter expansion within a semiclassical setting. We show that, for a massless scalar, the zero-mode sector can contain a contribution to the stress-energy tensor with equation of state $P = - ρ$ , behaving as a cosmological constant. Thus, the source driving an early-Universe de Sitter phase need not be determined solely by local terms in the action, but can also depend on the infrared structure of the quantum state. Nontrivial topology, as a concrete realization of de Sitter symmetry violation, turns the otherwise-unfixed infrared freedom in vacuum selection to a contribution directly relevant to the semiclassical expansion. This contribution could potentially be applicable to the current accelerated expansion of the Universe.
↳ hep-thastro-ph.COgr-qchep-ph1 citation
33
Coherent states of neutrinos in rotating matter
Alexander Breev🇷🇺 · Maxim Dvornikov🇷🇺
We study coherent states of neutrinos electroweakly interacting with rotating matter. We start with the Dirac equation for a massive neutrino propagating in background matter with a coordinate dependent effective potential. Then, we consider the limit of massless particles and the specific matter velocity profile. It allows us to reduce the neutrino Hamiltonian to the harmonic oscillator form. We find the exact solutions of the Dirac equation and construct the creation and annihilation operators. Using these results, we build the generalized coherent states of neutrinos. We provide the interpretation of these coherent states in terms of the classical physics. In particular, we demonstrate that the coherent states constructed approach plane waves in the limit of slow matter rotation. We also define the effective neutrino mass owing to the interaction of a massless neutrino with rotating matter. Then, we consider a special case of the generalized coherent states which are called the neutrino coherent states. The situation of the degenerate parameters of the system is also studied. Finally, we apply our results for astrophysical neutrinos propagating in dense matter of a rapidly rotating neutron star (NS). We calculate the effective neutrino masses for different neutrino energies for realistic parameters of NS.
↳ hep-thastro-ph.HEhep-ph0 citations
34
Efficient numerical evolution of self-gravitating systems with dark-matter-baryon scattering
Marc Kamionkowski🇺🇸 · Vera Gluscevic🇺🇸 · Kris Sigurdson🇨🇦
We present a fast algorithm to numerically evolve a spherically symmetric system consisting of dark matter and gas, including dark-matter-baryon scattering. The method augments the spherical N-body code NSphere, which collapses the six-dimensional phase space of a spherical collisionless system to three dimensions, with a one-dimensional Lagrangian treatment of gas. Dark-matter-baryon scattering is implemented as a Monte-Carlo process between the dark-matter numerical particles and the gas shells. We also implement an algorithm for radiative gas cooling that is valid for weak cooling. The gas, as well as dark-matter-baryon scattering and cooling, adds only incrementally to the run time of the code, allowing systems to be evolved on a laptop computer, a tiny fraction of the computational resources required for a full 3D N-body/hydro simulation. To illustrate, we show the evolution of a $\sim 1 0^{13} M_{⊙}$ halo with a dark-matter-baryon scattering cross section $σ_{tot} / m_{χ} = 0.1 cm^{2} g^{- 1}$ but no gas cooling. We then show examples with radiative gas cooling where the cooling is altered through interaction with dark-matter particles. The resulting code, NSphere-IDM, allows the implications of dark-matter interactions for galaxy evolution to be explored quickly over large volumes of the dark-matter parameter space, and other new physics (e.g., dark-matter self-interactions or anisotropy in the distribution function) is easily incorporated. The code can also provide useful calibrations and benchmarks for fully 3D N-body or hydrodynamical simulations.
↳ astro-ph.COastro-ph.GAhep-phhep-th0 citations
35
Compact Dark Matter with Globular Cluster Pulsars
Soobeom Chung🇺🇸 · Jeff A. Dror🇺🇸
Pulsars are exceptionally stable clocks, and a compact dark-matter object passing near the line of sight to a pulsar delays its pulses through the Shapiro effect. The number of detectable transits is set by the integral over the dark-matter density along the line of sight connecting the Earth and the pulsar. Established pulsars in pulsar timing arrays are typically within one kiloparsec of the Earth and hence sit in a dark-matter density comparable to our local value. In this work, we explore globular clusters in the inner Galaxy as targets to search for compact dark matter. These high-pulsar-density environments can be cheaply observed with a single telescope beam and enjoy a large dark-matter crossing rate. Additionally, since the recently detected nanohertz gravitational-wave background is nearly common to the cluster's pulsars, a multi-pulsar analysis can remove much of its contribution. Ranking known clusters, we find that Terzan 5, with 49 pulsars, offers the best reach. A forty-year campaign of weekly four-hour visits at the sensitivity envisioned for the second phase of the Square Kilometre Array (SKA) would probe compact objects making up $6%$ of the dark matter at $0.02 M_{⊙}$ . Finally, we estimate the foreground from stars and stellar remnants in Terzan 5 and along the sightline. It is subdominant near the most sensitive low-mass part of the SKA benchmark, but becomes important over parts of the stellar mass range.
↳ astro-ph.HEastro-ph.COhep-ph0 citations
36
Ergodic topology sampling toward the continuum with Stochastic Normalizing Flows
Claudio Bonanno🇨🇭 · Andrea Bulgarelli🇩🇪 · Elia Cellini🇬🇧 · Alessandro Nada🇮🇹 · Dario Panfalone🇮🇹 · Davide Vadacchino🇬🇧 · Lorenzo Verzichelli🇮🇹
In this work we provide numerical evidence that topological freezing in $SU (3)$ Yang-Mills theory can be mitigated with a flow-based approach, as tested at lattice spacings as fine as 0.03~fm. We do so by analyzing the scaling of the costs of a computational strategy based on the combination of open boundary conditions and Stochastic Normalizing Flows. We show that the integrated autocorrelation time of the squared topological charge and the statistical uncertainty on the topological susceptibility remain under control throughout the explored parameter range with currently available computational resources. This marks an important step toward the use of even more efficient flow-based architectures for ergodic sampling of topology in state-of-the-art lattice gauge theory calculations.
↳ hep-latcond-mat.stat-mechcs.LGhep-ph0 citations
37
Dark Matter Particle Explorer: Ten-Year On-Orbit Performance and Scientific Outcomes
Jian-Hua Guo · Chuan Yue · Yun-Long Zhang · Yi-Zhong Fan · Jin Chang
The Dark Matter Particle Explorer (DAMPE, also known as ``Wukong'') is the first scientific space mission within the framework of the Strategic Pioneer Program on Space Science of the Chinese Academy of Sciences. The main scientific objectives of DAMPE include indirect detection of dark matter, cosmic-ray physics, and high energy gamma-ray astronomy. Thanks to its large geometrical factor and thick imaging calorimeter, DAMPE could effectively detect cosmic-ray electrons (including positrons) and gamma-rays up to 10~TeV, and nuclei up to PeV. Since launched on 17 December 2015 into a Sun-synchronous orbit, DAMPE has been smoothly operating on orbit for more than ten years. Here we present an overview of instrument, on-orbit status, and highlight scientific results of DAMPE, including the measurements of the all-electron energy spectrum and the spectra of protons and other nuclei, and high energy gamma-ray line search.
↳ astro-ph.HEastro-ph.IMhep-exhep-ph
38
Identification of ultra-high-energy neutrinos in vertical air showers with surface detectors
Jaime Alvarez-Muñiz · Ruben Conceição · Pedro J. Costa · David Dias · Mário Pimenta
We investigate the potential of surface detector arrays to identify ultra-high-energy neutrinos using vertical air showers with zenith angle $θ \leq 6 0^{\circ}$ , a region largely unexplored in current searches. The method exploits the enhanced electromagnetic component at ground level arising from energetic leptons produced in neutrino interactions. Using detailed air-shower and detector simulations, we show that observables sensitive to the electromagnetic and muonic content provide genuine discrimination between neutrino-induced and hadron-induced showers. This is demonstrated both with idealized shower quantities and with realistic detector-level signals based on water-Cherenkov and scintillator detectors. The corresponding neutrino identification efficiency is used to derive the effective mass and, primarily, the effective area of the array under background-rejection requirements appropriate to targeted multi-messenger searches. Although not competitive with inclined-shower searches under the stringent background rejection factors required for diffuse-flux analyses, this approach establishes the feasibility of a vertical detection channel, extending the field of view of surface arrays and providing a complementary tool for multi-messenger observations of transient sources.
↳ astro-ph.HEhep-exhep-ph
39
Minkowski Functionals of CII Line Intensity Maps: Probing Astrophysics and Primordial Features
Sandeep Kumar Acharya · Pravabati Chingangbam
Line intensity mapping aims to measure the total cumulative light of spectral lines from galaxies, without resolving individual sources. In this work, we investigate mock intensity maps of ionized carbon CII using Minkowski functionals, which capture the morphological properties of the maps. We generate semi-numerical simulations of CII intensity maps at $z \approx 6$ and $7.6$ , adopting an astrophysical model that relates CII line luminosity to the mass of the host dark matter halos. We find that Minkowski functionals can provide tight constraints on the astrophysical model parameters in the presence of noise characteristics expected from the upcoming CCAT survey. We further investigate the prospects of probing a bump-like feature superimposed on the standard single power-law primordial power spectrum. Using a Fisher matrix formalism, we demonstrate that the effects of this primordial feature can be disentangled from those of the astrophysical model parameters. Combining measurements across multiple smoothing scales as well as redshifts can further improve the constraints and enhance the prospects for detecting such primordial features.
↳ astro-ph.COastro-ph.GAhep-ph
40
One generation of the Standard Model as a quantum error-correcting code
Shiroman Prakash · K. L. Ramya
Together with a right-handed neutrino, the fermions of one generation of the Standard Model are labelled by five bits, a combinatorial structure tied to anomaly cancellation. We make this precise. Anomaly cancellation is the vanishing of a cubic form, the defining property of triorthogonal codes, the quantum error-correcting codes behind magic state distillation. Removing the right-handed neutrino gives a $[[15, 1, 3]]_{p}$ code for every prime $p$ , including the Bravyi-Kitaev code for $p = 2$ . For qutrits it is the unique shortest distance-three triorthogonal code.
↳ hep-thcs.IThep-phmath.IT+10 citations
41
Jianmu-Q: Bridging Quantum Field Theory and Quantum Hardware with AI Agents
Xiaolin Wang · Xingyu Guo · Jinyang Li · Tianyin Li · Enke Wang · Lingxiao Wang · Hongxi Xing
Quantum computing offers a promising approach to non-perturbative simulations of quantum field theories, particularly for real-time dynamics and systems affected by the sign problem. Yet translating continuum field theories into quantum computations remains a challenging interdisciplinary task. Here we introduce \texttt{Jianmu-Q}, a multi-agent framework that transforms natural-language descriptions of quantum field theories into quantum simulation workflows. Specialized agents handle theoretical formulation, lattice discretization, qubit mapping, and circuit design, while physical consistency checks and independent numerical calculations provide validation throughout the workflow. We benchmark the framework on three field theories of increasing complexity: the $(1 + 1)$ -dimensional Nambu--Jona-Lasinio and Schwinger models, and a $(2 + 1)$ -dimensional $Z_{2}$ gauge theory. Across these systems, noiseless quantum-circuit simulations converge toward independent exact-diagonalization and tensor-network results, while selected circuits are executed on IBM quantum hardware, demonstrating an end-to-end, validation-guided approach to quantum simulation of field theories.
↳ hep-lathep-phquant-ph
42
Stimulated capture of axion dark matter around primordial black holes
Nuno P. Branco · João G. Rosa
We study the stimulated capture of axion and axion-like particles around primordial black holes, mediated by quartic self-interactions. We identify the parametric regions where Bose-enhanced growth overcomes cosmological dilution and derive analytic criteria for efficient formation and long-term survival of the hydrogenic ground-state cloud, confronting them with current bounds on axion-photon couplings. We discuss observational implications of these PBH+cloud systems, including resonant axion-to-photon conversion in neutron star magnetospheres and finite-size microlensing distortions. In the former case, the resonance condition selects a conversion shell outside the neutron star surface, and we show that the large axion occupation number of the cloud can compensate for the small conversion probability. The resulting transient line flux densities can exceed nominal VLA and ALMA sensitivities in regions where the Galactic encounter rate is observationally relevant. Independently, when the cloud size becomes comparable to or larger than the Einstein radius, finite-size effects can modify the standard point-lens microlensing light curve.
↳ astro-ph.COgr-qchep-ph
43
The hadronic-vacuum-polarization contribution to the muon anomalous magnetic moment in isospin-symmetric lattice QCD with twisted-mass fermions
C. Alexandrou · S. Bacchio · A. De Santis · A. Evangelista · J. Finkenrath · R. Frezzotti · G. Gagliardi · M. Garofalo · N. Kalntis · B. Kostrzewa · V. Lubicz · L. Maio and 9 other authors
We present a lattice-QCD calculation of the leading-order hadronic-vacuum-polarization (HVP) contribution to the anomalous magnetic moment of the muon in isospin-symmetric QCD. We employ the gauge configurations generated by the Extended Twisted Mass Collaboration (ETMC) with $N_{f} = 2 + 1 + 1$ flavors of Wilson-clover twisted-mass quarks at four lattice spacings and at values of the quark-mass parameters matching the definition of isospin-symmetric QCD given in the FLAG review 2024 and in the 2025 edition of the Muon $g - 2$ Theory Initiative White Paper (WP25). After retuning the simulation parameters to precisely match these two definitions of isospin-symmetric QCD, and after carrying out an extrapolation to the continuum limit based on the data at lattice spacings $a ≃ 0.049, 0.057, 0.068$ and $0.079$ ~fm, and spatial lattice sizes up to $L ≃ 7.7$ ~fm, we obtain $a_{μ}^{HVP, FLAG} (iso) = (720.0 \pm 6.9) \times 1 0^{- 10}$ and $a_{μ}^{HVP, WP25} (iso) = (714.8 \pm 7.4) \times 1 0^{- 10}$ . Our results, which have a relative uncertainty of about $1%$ , agree well with the corresponding determinations by other lattice groups. After adding to our determination of $a_{μ}^{HVP, WP25} (iso)$ the leading isospin-breaking corrections provided in the WP25, namely $a_{μ}^{HVP, WP25} (IB) = 0.1 (3.4) \times 1 0^{- 10}$ , we obtain for the full HVP the value $a_{μ}^{HVP} = (714.9 \pm 8.1) \times 1 0^{- 10}$ . This result translates into a Standard Model prediction for the muon anomalous magnetic moment that is fully consistent with the latest result by the Fermilab Muon $g - 2$ experiment and strengthens the tension between lattice QCD and data-driven (pre-CMD3) dispersive determinations.
↳ hep-lathep-phhep-th

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