Mon·Feb 26, 2024Monday·February 26, 2024

1. 01*

   Hyperon semileptonic decays in QCD sum rules

   Sheng-Qi Zhang🇨🇳 · Xuan-Heng Zhang🇨🇳 · Cong-Feng Qiao🇨🇳

   We investigate the hyperon semileptonic decays within the framework of QCD sum rules. The flavor $SU(3)$ symmetry breaking effects are analyzed via the relevant form factors and corresponding branching fractions. Employing the $z$-series parameterization to capture the $q^2$ dependence of form factors, we calculate the hyperon semileptonic decay rates and confront them with the recent experimental measurements. Moreover, we calculate as well the non-standard tensor form factors, which involve certain new physics beyond the standard model.

   hep-phJHEP(2024)·24 citations
2. 02*

   Gluonic contributions to semi-inclusive DIS in the target fragmentation region

   Kai-Bao Chen🇨🇳 · Jian-Ping Ma🇨🇳 · Xuan-Bo Tong🇫🇮

   We study one-loop contributions to semi-inclusive deep inelastic scattering in the target fragmentation region for a polarized lepton beam and nucleon target. Complete one-loop results at leading twist are derived, with a particular focus on the gluonic channel. It shows that four structure functions are generated uniquely by the gluon fracture functions starting at one-loop. Additionally, we obtain two structure functions associated with the longitudinal polarization of the virtual photon, and they are contributed by both gluon and quark channels. By combining existing twist-3 results, all eighteen structure functions for the studied process are predicted in terms of fracture functions convoluted with perturbative coefficient functions.

   hep-phJHEP(2024)·9 citations
3. 03*

   Gauge coupling unification and proton decay via 45 Higgs boson in SU(5) GUT

   Naoyuki Haba🇯🇵 · Keisuke Nagano🇯🇵 · Yasuhiro Shimizu🇯🇵 · Toshifumi Yamada🇯🇵

   We study the gauge coupling unification (GCU) and proton decay in a non-supersymmetric SU(5) grand unified theory (GUT) incorporating a 45 representation Higgs field. Our analysis is based on the assumption that Georgi-Jarlskog-type mass matrices for fermions are responsible for explaining the mass ratio of the strange quark and the muon. We examine the conditions of GCU, taking into account the possibility that certain components of the 45 Higgs field have masses much smaller than the GUT scale. We have found that to satisfy the GCU conditions, at least two components of the 45 Higgs field should have such small masses. We search the parameter space to identify regions where the GCU conditions are satisfied, in the scenarios where two or three components of the 45 Higgs boson are hierarchically light. If the colored Higgs component of the 45 Higgs boson has a mass much smaller than the GUT scale, proton decay via colored Higgs boson exchange can occur with an observably large rate. We estimate the mass bounds for the colored Higgs component from the proton decay search at Super- Kamiokande and thereby further restrict the parameter space.

   hep-phPTEP(2024)·7 citations
4. 04*

   Polarization Signals from Axion-Photon Resonant Conversion in Neutron Star Magnetosphere

   Ningqiang Song🇨🇳 · Liangliang Su🇨🇳 · Lei Wu🇨🇳

   Neutron stars provide ideal astrophysical laboratories for probing new physics beyond the Standard Model. If axions exist, photons can develop linear polarization during photon-axion conversion in the magnetic field of a neutron star. We find that the plasma in the neutron star magnetosphere could dramatically enhance the polarization through the resonant conversion effect. With the polarization measurements from PSR B0656+14, 4U 0142+61, and the benchmark polarization measurement in the mid-infrared band, we demonstrate that optical and infrared polarization from neutron stars can provide strong constraints on the axion-photon coupling over a broad axion mass range $10^{-11}\lesssim m_a\lesssim 10^{-3}$ eV.

   hep-phPRD(2025)·24 citations
5. 05*

   Affleck-Dine Dirac Leptogenesis

   Neil D. Barrie🇰🇷 · Chengcheng Han🇨🇳

   We present a minimal framework that realises successful Dirac Leptogenesis through the Affleck-Dine mechanism. A single right-handed neutrino and a neutrinophillic Higgs doublet are introduced to the Standard Model, which couple via a Yukawa interaction. The inflationary setting is induced by a combination of the two Higgs doublets, with their global symmetry violating interactions leading to a net charge generation via the Affleck-Dine mechanism. This simple Standard Model extension exhibits a unique and connected set of phenomenological implications including the resultant baryon asymmetry, inflationary predictions, cosmological implications, relic right-handed neutrinos, and its low energy phenomenology, while also being able to be embedded in various neutrino mass generating mechanisms.

   hep-phastro-ph.COhep-th8 citations
6. 06*

   Functional renormalization group study of the quark-meson model with omega and rho vector mesons

   Mohammed Osman🇨🇳 · Defu Hou🇨🇳 · Wentao Wang🇨🇳 · Hui Zhang🇨🇳

   We employ the functional renormalization group flow equations to investigate the phase structure of the two-flavor quark-meson model in the presence of a finite isospin chemical potential, incorporating interactions with omega and rho vector mesons. For comparison, we also compute the phase diagram in the chiral limit using the mean-field approximation. Our findings demonstrate that omega and rho mesons affect the phase structure in markedly distinct ways, and the introduction of an isospin chemical potential leads to significant modifications in the phase boundaries and critical region. Increasing the isospin chemical potential lowers the tricritical points temperature, and tends to suppress the unphysical ``back-bending" of the FRG phase boundary at low temperature.

   hep-phnucl-thEPJC(2025)·7 citations
7. 07*

   $t\bar{t}b\bar{b}$ at NLO precision in a variable flavor number scheme

   Lars Ferencz🇩🇪 · Stefan Höche🇺🇸 · Judith Katzy🇩🇪 · Frank Siegert🇩🇪

   Top-quark pair production in association with two b-jets is computed at next-to-leading order QCD precision, including effects of the b-quark mass, and matched to a $t\bar{t}$+jets simulation in a variable flavor number scheme. The Monte Carlo realization of this method, called fusing, consistently embeds the four-flavor calculation in a particle-level event generator. As a first phenomenological application, we present observables relevant to the data-driven estimation of irreducible backgrounds to $t\bar{t}H$-production.

   hep-phJHEP(2024)·5 citations
8. 08*

   Classifier Surrogates: Sharing AI-based Searches with the World

   Sebastian Bieringer🇩🇪 · Gregor Kasieczka🇩🇪 · Jan Kieseler🇩🇪 · Mathias Trabs🇩🇪

   In recent years, neural network-based classification has been used to improve data analysis at collider experiments. While this strategy proves to be hugely successful, the underlying models are not commonly shared with the public and rely on experiment-internal data as well as full detector simulations. We show a concrete implementation of a newly proposed strategy, so-called Classifier Surrogates, to be trained inside the experiments, that only utilise publicly accessible features and truth information. These surrogates approximate the original classifier distribution, and can be shared with the public. Subsequently, such a model can be evaluated by sampling the classification output from high-level information without requiring a sophisticated detector simulation. Technically, we show that Continuous Normalizing Flows are a suitable generative architecture that can be efficiently trained to sample classification results using Conditional Flow Matching. We further demonstrate that these models can be easily extended by Bayesian uncertainties to indicate their degree of validity when confronted with unknown inputs by the user. For a concrete example of tagging jets from hadronically decaying top quarks, we demonstrate the application of flows in combination with uncertainty estimation through either inference of a mean-field Gaussian weight posterior, or Monte Carlo sampling network weights.

   hep-phhep-exphysics.data-anEPJC(2024)·7 citations
9. 09*

   Possible spectral irregularities in the AMS-02 positron spectrum

   Xing-Jian Lv🇨🇳 · Xiao-Jun Bi🇨🇳 · Kun Fang🇨🇳 · Peng-Fei Yin🇨🇳 · Meng-Jie Zhao🇨🇳

   The excesses in the electron and positron spectra observed by many experiments, such as PAMELA and AMS-02, have sparked significant theoretical investigation. It is not easy to distinguish the two primary hypotheses dark matter annihilation/decay and pulsars from the spectral features. Should pulsars be the source of this excess, the expected variability in their distribution may introduce distinct irregularities in the positron energy spectrum. In this study, we use an irregularity estimator to detect these potential features in the positron energy spectrum of AMS-02. Our analysis of the current AMS-02 data reveals these spectral irregularities with a statistical significance of $1.75\sigma$. However, our projection indicates that, with AMS-02 data collected over a period of 20 years, such irregularities could be identified with a confidence level of $3\sigma$ level in 71\% of our simulations.

   ↳ astro-ph.HEhep-phPRD(2024)·1 citation
10. 10*

    Primordial Black Holes as a dark matter candidate -- a brief overview

    Anne M. Green🇬🇧

    Historically the most popular dark matter candidates have been new elementary particles, such as Weakly Interacting Massive Particles and axions. However Primordial Black Holes (PBHs), black holes formed from overdensities in the early Universe, are another possibility. The discovery of gravitational waves from mergers of tens of Solar mass black hole binaries by LIGO-Virgo has generated a surge in interest in PBH dark matter. We overview the formation of PBHs, observational probes of their abundance, and some of the key open questions in the field.

    ↳ astro-ph.COhep-phNPB(2024)·84 citations
11. 11*

    Bubble-wall velocity in local thermal equilibrium: hydrodynamical simulations vs analytical treatment

    Tomasz Krajewski🇵🇱 · Marek Lewicki🇵🇱 · Mateusz Zych🇵🇱

    We perform real-time hydrodynamical simulations of the growth of bubbles formed during cosmological first-order phase transitions under the assumption of local thermal equilibrium. We confirm that pure hydrodynamic backreaction can lead to steady-state expansion and that bubble-wall velocity in such case agrees very well with the analytical estimates. However, this is not the generic outcome. Instead, it is much more common to observe runaways, as the early-stage dynamics right after the nucleation allow the bubble walls to achieve supersonic velocities before the heated fluid shell in front of the bubble is formed. This effect is not captured by other methods of calculation of the bubble-wall velocity which assume stationary solutions to exist at all times and would have a crucial impact on the possible generation of both baryon asymmetry and gravitational wave signals.

    ↳ astro-ph.COhep-phJHEP(2024)·54 citations
12. 12*

    Detailed Report on the Measurement of the Positive Muon Anomalous Magnetic Moment to 0.20 ppm

    D. P. Aguillard (33)🇺🇸 · T. Albahri (30)🇬🇧 · D. Allspach (7)🇺🇸 · A. Anisenkov (4 and 38)🇷🇺 · K. Badgley (7)🇺🇸 · S. Baeßler (35 and 39)🇺🇸 · I. Bailey (17 and 40)🇬🇧 · L. Bailey (27)🇬🇧 · V. A. Baranov (15)🇷🇺 · E. Barlas-Yucel (28)🇺🇸 · T. Barrett (6)🇺🇸 · E. Barzi (7)🇺🇸 and 181 other authors

    We present details on a new measurement of the muon magnetic anomaly, $a_{\mu }=(g_{\mu }-2)/2$. The result is based on positive muon data taken at Fermilab's Muon Campus during the 2019 and 2020 accelerator runs. The measurement uses $3.1$ GeV$/c$ polarized muons stored in a $7.1$-m-radius storage ring with a $1.45$ T uniform magnetic field. The value of $a_{\mu }$ is determined from the measured difference between the muon spin precession frequency and its cyclotron frequency. This difference is normalized to the strength of the magnetic field, measured using Nuclear Magnetic Resonance (NMR). The ratio is then corrected for small contributions from beam motion, beam dispersion, and transient magnetic fields. We measure $a_{\mu }=116592057(25)\times 10^{-11}$ (0.21 ppm). This is the world's most precise measurement of this quantity and represents a factor of $2.2$ improvement over our previous result based on the 2018 dataset. In combination, the two datasets yield $a_{\mu }(\text{FNAL})=116592055(24)\times 10^{-11}$ (0.20 ppm). Combining this with the measurements from Brookhaven National Laboratory for both positive and negative muons, the new world average is $a_{\mu }$(exp) $=116592059(22)\times 10^{-11}$ (0.19 ppm).

    ↳ hep-exhep-phnucl-exPRD(2024)·113 citations
13. 13*

    Induced moduli oscillation by radiation and space expansion in a higher-dimensional model

    Hajime Otsuka🇯🇵 · Yutaka Sakamura🇯🇵

    We investigate the cosmological expansion of the 3D space in a 6D model compactified on a sphere, beyond the 4D effective theory analysis. We focus on a case that the initial temperature is higher than the compactification scale. In such a case, the pressure for the compact space affects the moduli dynamics and induces the moduli oscillation even if they are stabilized at the initial time. Under some plausible assumptions, we derive the explicit expressions for the 3D scale factor and the moduli background in terms of analytic functions. Using them, we evaluate the transition times between different cosmological eras as functions of the model parameters and the initial temperature.

    ↳ hep-thhep-phPRD(2024)·2 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.