HEP Phenomenology·hep-ph

Mon·Oct 7, 2024Monday·October 7, 2024

13 papers—10 primary·3 cross-listed·reconstructed*

01*
FAIR Universe HiggsML Uncertainty Dataset and Competition
Lisa Benato🇦🇹 · Wahid Bhimji🇺🇸 · Paolo Calafiura🇺🇸 · Ragansu Chakkappai🇫🇷 · Po-Wen Chang🇺🇸 · Yuan-Tang Chou🇺🇸 · Sascha Diefenbacher🇺🇸 · Jordan Dudley🇺🇸 · Ibrahim Elsharkawy🇺🇸 · Steven Farrell🇺🇸 · Aishik Ghosh🇺🇸 · Cristina Giordano🇦🇹 and 17 other authors
The FAIR Universe HiggsML Uncertainty Challenge focused on measuring the physical properties of elementary particles with imperfect simulators. Participants were required to compute and report confidence intervals for a parameter of interest regarding the Higgs boson while accounting for various systematic (epistemic) uncertainties. The dataset is a tabular dataset of 28 features and 280 million instances. Each instance represents a simulated proton-proton collision as observed at CERN's Large Hadron Collider in Geneva, Switzerland. The features of these simulations were chosen to capture key characteristics of different types of particles. These include primary attributes, such as the energy and three-dimensional momentum of the particles, as well as derived attributes, which are calculated from the primary ones using domain-specific knowledge. Additionally, a label feature designates each instance's type of proton-proton collision, distinguishing the Higgs boson events of interest from three background sources. As outlined in this paper, the permanent release of the dataset allows long-term benchmarking of new techniques. The leading submissions, including Contrastive Normalising Flows and Density Ratios estimation through classification, are described. Our challenge has brought together the physics and machine learning communities to advance our understanding and methodologies in handling systematic uncertainties within AI techniques.
hep-phcs.LGhep-exphysics.data-an15 citations
02*
SIMP dark matter during reheating
Debtosh Chowdhury🇮🇳 · Sudipta Show🇮🇳
Strongly interacting massive particle (SIMP) has become one of the promising dark matter (DM) candidates due to its capability of addressing the small-scale anomaly, where the final DM abundance is set via the freeze-out of $3 \to 2$ or $4 \to 2$ annihilation process involving solely the dark sector particles. In this work, we explore the freeze-out of SIMP DM during the inflationary reheating epoch. During reheating, the radiation energy density evolves differently based on the shape of inflaton potential and spin of its decay products than the standard radiation-dominated picture; as a result, in this scenario, the freeze-out temperature varies distinctly with DM mass compared to the standard case. Large entropy injection due to inflaton decay demands a smaller cross-section to satisfy the observed relic than the standard radiation-dominated freeze-out case. The required cross-section, satisfying the relic density constraint and the maximum allowed thermally averaged cross-section by the unitarity of the $S$ -matrix, set an upper limit on the DM mass. The upper bound on the mass of the dark matter for $3 \to 2$ ( $4 \to 2$ ) is $1$ GeV ( $7$ MeV), assuming a radiation-dominated background. Interstingly, these limits get relaxed to $1 0^{6}$ ( $1 0^{4}$ ) GeV for $3 \to 2$ ( $4 \to 2$ ) SIMP dark matter for quadratic inflaton potential. We find that a small amount of DM parameter space survives for reheating with quadratic inflaton potential after considering the lower bound of reheating temperature, put by the latest CMB observation depending on the inflationary models. In the case of the quartic inflaton potential, the allowed DM parameter space gets reduced compared to the quadratic case.
hep-phastro-ph.COJCAP(2025)·6 citations
03*
Antineutrinos produced from $β$ decays of neutrons cannot be in coherent superpositions of different mass eigenstates
Shi-Biao Zheng🇨🇳
The entire wavefunction of the antineutrino-proton-electron system, produced by the $β$ decay of a neutron is analyzed. It is proven that the antineutrino cannot be in coherent superpositions of different mass eigenstates, irrespective of the initial momentum distribution of the neutron.
hep-phquant-ph2 citations
04*
Superconducting strings in the two-Higgs doublet model
Richard Battye🇬🇧 · Steven Cotterill🇬🇧
We present superconducting vortex solutions in the two-Higgs doublet model which has a gauged $U (1)$ Higgs-family symmetry. We write down an ansatz for the solution and study its basic properties, for the case of both global and gauged symmetries. We demonstrate its prima-facie stability using 3D numerical simulations of a global version of the theory, observing the flow of current along the string. We discuss how generic such a phenomena might be and the possible consequences if such a model is found in nature.
hep-phastro-ph.COhep-thPLB(2025)·3 citations
05*
Master integrals for $e^{+} e^{-} \to 2 γ$ process at large energies and angles
Roman N. Lee🇷🇺 · Vyacheslav A. Stotsky🇷🇺
We calculate two-loop massive master integrals for $e^{+} e^{-} \to 2 γ$ in terms of generalized power series with respect to electron mass. The coefficients of this series are expressed via Goncharov's polylogarithms. Our approach exploits a number of modern multiloop methods: IBP reduction, differential equations for master integrals, Frobenius method, reduction to $ϵ$ -form, and DRA method.
hep-phJHEP(2024)·6 citations
06*
On the orthogonal matrix in the Casas-Ibarra parametrization for the Yukawa interactions of Majorana neutrinos
Zhi-zhong Xing🇨🇳
The Casas-Ibarra (CI) parametrization of the Yukawa coupling matrix of Majorana neutrinos is generalized by considering the exact seesaw relation and including non-unitarity of the $3 \times 3$ Pontecorvo-Maki-Nakagawa-Sakata (PMNS) flavor mixing matrix. With the help of a full $6 \times 6$ Euler-like block description of the flavor structure for the seesaw mechanism, we find that the orthogonal matrix $O$ in the CI parametrization can be expressed as $O_{ij} = M_{j} / m_{i} F_{ij}$ with $m_{i}$ and $M_{j}$ being the masses of light and heavy Majorana neutrinos and $F_{ij}$ consisting of the PMNS and active-sterile flavor mixing parameters (for $i, j = 1, 2, 3$ ). Assuming a specific pattern of $O$ is therefore equivalent to imposing some special conditions on the seesaw parameter space.
hep-phNPB(2024)·2 citations
07*
Searching for type I seesaw mechanism in a two Heavy Neutral Leptons scenario at FCC-ee
Sehar Ajmal🇮🇹 · Patrizia Azzi🇮🇹 · Sofia Giappichini🇩🇪 · Markus Klute🇩🇪 · Orlando Panella🇮🇹 · Matteo Presilla🇩🇪 · Xunwu Zuo🇩🇪
This paper investigates the search for heavy neutral leptons (HNL) in the type I seesaw mechanism at the Future Circular Collider in its $e^{+} e^{-}$ stage (FCC-ee), considering a luminosity of 125 ab $^{- 1}$ collected at $s =$ 91.2 GeV. The study examines two generations of heavy neutral leptons produced in association with Standard Model (SM) neutrinos and decaying to a purely leptonic final state. This theoretical framework can explain neutrino oscillations and other open questions of the SM, providing a broader perspective on the relevance of this experimental search. The analysis is performed using a fast simulation of the IDEA detector concept to study potential HNL interactions at the FCC-ee. The sensitivity contours are obtained from a selection of kinematic variables aimed at improving the signal-to-background ratio for the prompt production case. In the case of long-lived HNLs, the background can be almost fully eliminated by exploiting their displaced decay vertices. The study shows that the FCC-ee has a significant sensitivity to observing these objects in a region of the phase space not accessible by other experiments.
hep-phhep-exJHEP(2025)·11 citations
08*
Accessing Generalized Parton Distributions through $2 \to 3$ exclusive processes
Goran Duplančić🇭🇷 · Saad Nabeebaccus🇫🇷 · Kornelija Passek-K.🇭🇷 · Bernard Pire🇫🇷 · Lech Szymanowski🇵🇱 · Samuel Wallon🇫🇷
We review our results on a new class of $2 \to 3$ exclusive processes, as a probe of both chiral-even and chiral-odd quark GPDs. We consider the exclusive photoproduction of a photon-meson pair, in the kinematics where the pair has a large invariant mass, described in the collinear factorization framework. We cover the whole kinematical range from medium energies in fixed target experiments to very large energies of colliders, by considering the experimental conditions of JLab 12-GeV, COMPASS, future EIC and LHC (in ultra-peripheral collisions) cases. Our analysis covers neutral and charged rho-mesons, as well as charged pions. The case of the rho-meson, depending on its polarization, provides access to either chiral-even or chiral-odd GPDs, at leading twist. We find that the order of magnitude of the obtained cross sections are sufficiently large for a dedicated experimental analysis to be performed, especially at JLab. Furthermore, we compute the linear photon beam polarization asymmetry, which we find to be sizeable, in the case of a longitudinally polarized $ρ$ -meson or of a charged pion. These predictions are obtained for both asymptotic distribution amplitude (DA) and holographic DA.
hep-phnucl-thPoS(2025)·0 citations
09*
Unearthing Neutrino Decoherence from Quantum Spacetime: An Open Quantum Systems Perspective
Partha Nandi🇿🇦 · Tiasha Bhattacharyya🇮🇳
We investigated the influence of $\kappa$ Minkowski-type quantum spacetime on neutrino oscillations, revealing that spacetime fluctuations introduce a unique energy-dependent power law, $E^{-4}$, in the decoherence effect for relic neutrinos. This effect is particularly pronounced for low-energy neutrinos, such as those from the cosmic neutrino background ( $C ν B$ ). Our results indicate the potential for new models of low-energy quantum gravity-induced decoherence, which could pave the way for future experiments, such as IceCube-Gen2 and KM3NeT, to further constrain the deformation parameter.
hep-phgr-qchep-th1 citation
10*
Axion Couplings in Heterotic String Theory
Prateek Agrawal🇬🇧 · Michael Nee🇺🇸 · Mario Reig🇬🇧
We study the coupling of axions to gauge bosons in heterotic string theory. The axion-gauge boson couplings in the low energy 4d theory are derived by matching mixed anomalies between higher-form global symmetries and the zero-form gauge symmetry in the 10d theory. When the standard model gauge group is embedded in a single simple group in the 10d theory -- as is the case for almost all heterotic models studied in the literature -- the ratio of the axion-photon coupling to the axion mass is bounded above by the QCD line. This bound is relevant for a large number of axion searches which have sensitivity to axion parameter space above this line. The discovery of an axion in these searches will rule out a large class of heterotic models, making such a signal challenging to explain within heterotic string theory.
hep-phhep-thJHEP(2025)·39 citations
11*
Light Nuclei Femtoscopy and Baryon Interactions in 3 GeV Au+Au Collisions at RHIC
The STAR Collaboration
We report the measurements of proton-deuteron ( $p$ - $d$ ) and deuteron-deuteron ( $d$ - $d$ ) correlation functions in Au+Au collisions at $s_{NN}$ = 3 GeV using fixed-target mode with the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC). For the first time, the source size ( $R_{G}$ ), scattering length ( $f_{0}$ ), and effective range ( $d_{0}$ ) are extracted from the measured correlation functions with a simultaneous fit. The spin-averaged $f_{0}$ for $p$ - $d$ and $d$ - $d$ interactions are determined to be -5.28 $\pm$ 0.11(stat.) $\pm$ 0.82(syst.) fm and -2.62 $\pm$ 0.02(stat.) $\pm$ 0.24(syst.) fm, respectively. The measured $p$ - $d$ interaction is consistent with theoretical calculations and low-energy scattering experiment results, demonstrating the feasibility of extracting interaction parameters using the femtoscopy technique. The reasonable agreement between the experimental data and the calculations from the transport model indicates that deuteron production in these collisions is primarily governed by nucleon coalescence.
↳ nucl-exhep-exhep-phnucl-thPLB(2025)·21 citations
12*
Moments of Axial-Vector GPD from Lattice QCD: Quark Helicity, Orbital Angular Momentum, and Spin-Orbit Correlation
Shohini Bhattacharya🇺🇸 · Krzysztof Cichy🇵🇱 · Martha Constantinou🇺🇸 · Xiang Gao🇺🇸 · Andreas Metz🇺🇸 · Joshua Miller🇺🇸 · Swagato Mukherjee🇺🇸 · Peter Petreczky🇺🇸 · Fernanda Steffens🇩🇪 · Yong Zhao🇺🇸
In this work, we present a lattice QCD calculation of the Mellin moments of the twist-2 axial-vector generalized parton distribution (GPD), $H (x, ξ, t)$ , at zero skewness, $ξ$ , with multiple values of the momentum transfer, $t$ . Our analysis employs the short-distance factorization framework on ratio-scheme renormalized quasi-GPD matrix elements. The calculations are based on an $N_{f} = 2 + 1 + 1$ twisted mass fermions ensemble with clover improvement, a lattice spacing of $a = 0.093$ fm, and a pion mass of $m_{π} = 260$ MeV. We consider both the iso-vector and iso-scalar cases, utilizing next-to-leading-order perturbative matching while omitting the disconnected contributions and gluon mixing in the iso-scalar case. For the first time, we determine the Mellin moments of $H$ up to the fifth order. From these moments, we discuss the quark helicity and orbital angular momentum contributions to the nucleon spin, as well as the spin-orbit correlations of the quarks. Additionally, we perform a Fourier transform over the momentum transfer, which allows us to explore the spin structure in the impact-parameter space.
↳ hep-lathep-exhep-phnucl-thJHEP(2025)·29 citations
13*
Is the $w_{0} w_{a}$ CDM cosmological parameterization evidence for dark energy dynamics partially caused by the excess smoothing of Planck CMB anisotropy data?
Chan-Gyung Park🇰🇷 · Javier de Cruz Perez🇪🇸 · Bharat Ratra🇺🇸
We study the performance of the spatially-flat dynamical dark energy (DE) $w_{0} w_{a}$ CDM parameterization, with redshift-dependent DE fluid equation of state parameter $w (z) = w_{0} + w_{a} z / (1 + z)$ , with and without a varying CMB lensing consistency parameter $A_{L}$ , against Planck cosmic microwave background (CMB) data (P18 and lensing) and a combination of non-CMB data composed of baryonic acoustic oscillation (BAO) measurements that do not include DESI BAO data, Pantheon+ type Ia supernovae (SNIa) observations, Hubble parameter [ $H (z)$ ] measurements, and growth factor ( $f σ_{8}$ ) data points. From our most restrictive data set, P18+lensing+non-CMB, for the $w_{0} w_{a}$ CDM+ $A_{L}$ parameterization, we obtain $w_{0} = - 0.879 \pm 0.060$ , $w_{a} = - 0.3 9_{- 0.22}^{+ 0.26}$ , the asymptotic limit $w (z \to \infty) = w_{0} + w_{a} = - 1.2 7_{- 0.17}^{+ 0.20}$ , and $A_{L} = 1.07 8_{- 0.040}^{+ 0.036}$ (all $1 σ$ errors). This joint analysis of CMB and non-CMB data favors DE dynamics over a cosmological constant at $\sim 1 σ$ and $A_{L} > 1$ at $\sim 2 σ$ , i.e. more smoothing of the Planck CMB anisotropy data than is predicted by the best-fit model. For the $w_{0} w_{a}$ CDM parameterization with $A_{L} = 1$ the evidence in favor of DE dynamics is larger, $\sim 2 σ$ , suggesting that at least part of the evidence for DE dynamics comes from the excess smoothing of the Planck CMB anisotropy data. For the $w_{0} w_{a}$ CDM parameterization with $A_{L} = 1$ , there is a difference of $2.8 σ$ between P18 and non-CMB cosmological parameter constraints and $2.7 σ$ between P18+lensing and non-CMB constraints. When $A_{L}$ is allowed to vary these tensions reduced to $1.9 σ$ and $2.1 σ$ respectively. Our P18+lensing+non-CMB data compilation positively favors the $w_{0} w_{a}$ CDM parameterization without and with a varying $A_{L}$ parameter over the flat $Λ$ CDM model, and $w_{0} w_{a}$ CDM+ $A_{L}$ is also positively favored over $w_{0} w_{a}$ CDM.
↳ astro-ph.COgr-qchep-phhep-thInt.J.Mod.Phys.D(2025)·106 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.