Thu·Mar 2, 2023Thursday·March 2, 2023

1. 01*

   Deeply-virtual Compton process $e^{-}N\to e^{-}\gamma \pi N$ to study nucleon to resonance transitions

   Kirill M. Semenov-Tian-Shansky🇰🇷 · Marc Vanderhaeghen🇩🇪

   We study the deeply-virtual Compton scattering (DVCS) process $e^{-}N\to e^{-}\gamma \pi N$ involving the transition between a nucleon and a nucleon resonance in the $\pi N$ system, within the framework of generalized parton distributions (GPDs). For the four lowest-lying nucleon resonances, $\Delta (1232)$, $P_{11}(1440)$, $D_{13}(1520)$, and $S_{11}(1535)$, we express the DVCS amplitude in the Bjorken limit in terms of corresponding nucleon-to-resonance GPDs. Building upon the knowledge of the well studied electromagnetic nucleon-to-resonance transition form factors, which map the quark charge densities in transverse position space, the corresponding GPDs will open the prospect to also access the longitudinal momentum distributions of quarks in the transition. We provide estimates for cross sections and beam-spin asymmetries in the first and second $\pi N$ resonance regions in the kinematics of forthcoming CLAS12 data from Jefferson Lab.

   hep-phnucl-thPRD(2023)·24 citations
2. 02*

   Reheating consistency condition on the classically conformal $U(1{)}_{B-L}$ Higgs inflation model

   Shinsuke Kawai🇰🇷 · Nobuchika Okada🇺🇸

   We revisit a cosmological scenario based on the classically conformal $U(1{)}_{B-L}$-extension of the Standard Model. Our focus is on the mechanism of reheating after inflation and the constraints on the model parameters. In this scenario, the inflationary dynamics is driven by the $U(1{)}_{B-L}$ Higgs field that is nonminimally coupled to gravity and breaks the $U(1{)}_{B-L}$ symmetry spontaneously as it acquires a vacuum expectation value through the Coleman-Weinberg mechanism. It is found that the reheating process proceeds stepwise, and as the decay channels of the $U(1{)}_{B-L}$ Higgs field are known, the reheating temperature is evaluated. The relation between the e-folding number of inflation and the reheating temperature provides a strong consistency condition on the model parameters, and we find that the recent cosmological data gives an upper bound on the $U(1{)}_{B-L}$ breaking scale $v_{BL}\lesssim 10^{12}$ GeV. The lower bound is $v_{BL}\gtrsim 10^6$ GeV, obtained as the condition for successful reheating in this model. The prediction for the cosmic microwave background (CMB) spectrum of this model fits extremely well with today's cosmological data. The model can be tested and is falsifiable by near future CMB observations, including the LiteBIRD and CMB-S4.

   hep-phastro-ph.COhep-thPRD(2023)·8 citations
3. 03*

   $J/\psi$ decay to $\varphi ,\omega ,K^{\ast 0}$ plus $f_0(1370)$, $f_0(1710)$, $K_0^{\ast }(1430)$, $f_2(1270)$, $f_2^{\prime }(1525)$ and $K_2^{\ast }(1430)$: role of the $D$-wave for tensor production

   Luciano M. Abreu🇧🇷 · Lianrong Dai🇨🇳 · Eulogio Oset🇪🇸

   We reassess the decay of the $J/\psi$ into an $\omega ,\varphi ,K^{\ast 0}$ and one of the $f_0(1370)$, $f_0(1710)$, $f_2(1270)$, $f_2^{\prime }(1525)$, $K_0^{\ast }(1430)$ and $K_2^{\ast }(1430)$ resonances. We benefit from previous works that considered this reaction as a $J/\psi$ decay into three vector mesons, with a scalar or tensor resonance being formed from the interaction of two of these vectors. The novelty here with respect to former studies is the investigation of the relation between the scalar meson and tensor productions for the first time. To this end, the spin structure of the four vectors present in the production vertex is analyzed, and the $D$-wave mechanism in the tensor production is included. Then, beyond the ratios studied previously involving scalar states and tensor states independently, new ratios relating the scalar and tensor meson productions are estimated. Our results suggest that the $D$-wave mechanism of tensor production assumes a relevant contribution. New experimental data reporting the angular distributions of these processes will be important for checking this conclusion.

   hep-phPLB(2023)·6 citations
4. 04*

   Gauged $U(1{)}_X$ breaking as origin of neutrino masses, dark matter and leptogenesis at TeV scale

   Toshinori Matsui🇰🇷 · Takaaki Nomura🇨🇳 · Kei Yagyu🇯🇵

   We propose a new mechanism which simultaneously explains tiny neutrino masses, stability of dark matter and baryon asymmetry of the Universe via leptogenesis due to the common origin: a spontaneous breaking of a $U(1{)}_X$ gauge symmetry at TeV scale. The $U(1{)}_X$ breaking provides small Majorana masses of vector-like leptons which generate small mass differences among them, and enhance their CP-violating decays via the resonant effect. Such CP-violation and lepton number violation turns out to be a sufficient amount of the observed baryon asymmetry through leptogenesis. The Majorana masses from the $U(1{)}_X$ breaking also induce radiative generation of masses for active neutrinos at one-loop level. Furthermore, a $Z_2$ symmetry appears as a remnant of the $U(1{)}_X$ breaking, which guarantees the stability of dark matter. We construct a simple renormalizable model to realize the above mechanism, and show a benchmark point which can explain observed neutrino oscillations, dark matter data and the baryon asymmetry at the same time.

   hep-phPRD(2023)·3 citations
5. 05*

   Regge models of proton diffractive dissociation based on factorization and structure functions

   László Jenkovszky🇺🇦 · Rainer Schicker🇩🇪 · István Szanyi🇭🇺

   Recent results by the authors on proton diffractive dissociation (single, double and central) in the low-mass resonance region with emphasis on the LHC kinematics are reviewed and updated. Based on the previous ideas that the contribution of the inelastic proton-Pomeron vertex can be described by the proton structure function, the contribution of the inelastic Pomeron-Pomeron vertex appearing in central diffraction is now described by a Pomeron structure function.

   hep-phEntropy(2022)·3 citations
6. 06*

   Resolving the polarization puzzles in $D^0\to VV$

   Ye Cao🇨🇳 · Yin Cheng🇨🇳 · Qiang Zhao🇨🇳

   We carry out a systematic analysis of the Cabbibo-favored (CF) and singly Cabbibo-suppressed (SCS) decays of $D^0\to VV$, and demonstrate that the long-distance mechanism due to the final-state interactions (FSIs) can provide a natural explanation for these mysterious polarization puzzles observed in $D^0\to VV$ in experiments. More observables, which can be measured at BESIII and possibly at LHCb, are also suggested.

   hep-phPRD(2024)·25 citations
7. 07*

   Improved Analysis of the Breakup Corrections to the High Energy ${}^3$He Beam Polarization measurements with HJET

   A. A. Poblaguev🇺🇸

   The requirements for hadron polarimetry at the future Electron Ion Collider (EIC) include measurements of the absolute helion (${}^3$He, $h$) beam polarization with systematic uncertainties better than ${\sigma }_P^{\text{syst}}/P\le 1\%$. Recently, it was suggested to utilize the Polarized Atomic Hydrogen Gas Jet Target (HJET) for precision measurement of the polarization of the $\sim$100 GeV/n helion beam. At the Relativistic Heavy Ion Collider, HJET serves to determine absolute proton beam polarization with low systematic uncertainties of about ${\delta }^{\text{syst}}P/P\lesssim 0.5\%$. To adapt the HJET method for the EIC helion beam, the experimentally determined ratio of the beam and target (jet) spin correlated asymmetries should be adjusted by the ratio of $p^{\uparrow }h$ and $h^{\uparrow }p$ analyzing powers $A_{\text{N}}^{ph}(t)/A_{\text{N}}^{hp}(t)$ which, in the leading order approximation, is predefined by magnetic moments of the proton and helion, $({\mu }_p-1)/({\mu }_h/2-1/3)$. However, to achieve the required accuracy in the measured polarization, the corrections due to hadronic spin-flip amplitudes and due to possible beam ${}^3$He breakup should be considered. Here a more accurate analysis of the possible breakup corrections to the measured ${}^3$He beam polarization is provided. The results confirm that the breakup corrections are negligible for the EIC helion beam absolute polarization measurement by HJET.

   hep-ph2 citations
8. 08*

   PE-GAN: Prior Embedding GAN for PXD images at Belle II

   Baran Hashemi🇩🇪 · Nikolai Hartmann🇩🇪 · Thomas Kuhr🇩🇪 · Martin Ritter🇩🇪 · Matej srebre🇩🇪

   The pixel vertex detector (PXD) is an essential part of the Belle II detector recording particle positions. Data from the PXD and other sensors allow us to reconstruct particle tracks and decay vertices. The effect of background hits on track reconstruction is simulated by adding measured or simulated background hit patterns to the hits produced by simulated signal particles. This model requires a large set of statistically independent PXD background noise samples to avoid a systematic bias of reconstructed tracks. However, data from the fine-grained PXD requires a substantial amount of storage. As an efficient way of producing background noise, we explore the idea of an on-demand PXD background generator using conditional Generative Adversarial Networks (GANs) with contrastive learning, adapted by the number of PXD sensors in order to both increase the image fidelity and produce sensor-dependent PXD hitmaps.

   hep-phcs.CVstat.MLEPJ Web Conf.(2021)·4 citations
9. 09*

   Dark-sector seeded solution to the strong CP problem

   H. B. Câmara🇵🇹 · F. R. Joaquim🇵🇹 · J. W. F. Valle🇪🇸

   We propose a novel realization of the Nelson-Barr mechanism "seeded'' by a dark sector containing scalars and vector-like quarks. Charge-parity (CP) and a ${\mathcal{Z}}_8$ symmetry are spontaneously broken by the complex vacuum expectation value of a singlet scalar, leaving a residual ${\mathcal{Z}}_2$ symmetry that stabilizes dark matter (DM). A complex Cabibbo-Kobayashi-Maskawa matrix arises via one-loop corrections to the quark mass matrix mediated by the dark sector. In contrast with other proposals where non-zero contributions to the strong CP phase arise at the one-loop level, in our case this only occurs at two loops, enhancing naturalness. Our scenario also provides a viable weakly interacting massive particle scalar DM candidate.

   hep-phPRD(2023)·6 citations
10. 10*

    QCD Running Couplings and Effective Charges

    A. Deur🇺🇸 · S. J.Brodsky🇺🇸 · C. D. Roberts🇨🇳

    We discuss our present knowledge of ${\alpha }_s$, the fundamental running coupling or effective charge of Quantum Chromodynamics (QCD). A precise understanding of the running of ${\alpha }_s(Q^2)$ at high momentum transfer, $Q$, is necessary for any perturbative QCD calculation. Equally important, the behavior of ${\alpha }_s$ at low $Q^2$ in the nonperturbative QCD domain is critical for understanding strong interaction phenomena, including the emergence of mass and quark confinement. The behavior of ${\alpha }_s(Q^2)$ at all momentum transfers also provides a connection between perturbative and nonperturbative QCD phenomena, such as hadron spectroscopy and dynamics. We first sketch the origin of the QCD coupling, the reason why its magnitude depends on the scale at which hadronic phenomena are probed, and the resulting consequences for QCD phenomenology. We then summarize latest measurements in both the perturbative and nonperturbative domains. New theory developments include the derivation of the universal nonperturbative behavior of ${\alpha }_s(Q^2)$ from both the Dyson-Schwinger equations and light-front holography. We also describe theory advances for the calculation of gluon and quark Schwinger functions in the nonperturbative domain and the relation of these quantities to ${\alpha }_s$. We conclude by highlighting how the nonperturbative knowledge of ${\alpha }_s$ is now providing a parameter-free determination of hadron spectroscopy and structure, a central and long-sought goal of QCD studies.

    hep-phPPNP(2024)·101 citations
11. 11*

    Pulsars as candidates of LHAASO sources J2226+6057, J1908+0621 and J1825-1326: The leptonic origin

    Zhe Chang🇨🇳 · Yu-Ting Kuang🇨🇳 · Xukun Zhang🇨🇳 · Jing-Zhi Zhou🇨🇳

    Recently, from 12 $\gamma$-ray Galactic sources, the LHAASO has detected ultrahigh-energy photons up to 1.4PeV. The $\gamma$-ray spectra of the sources J2226+6057, J1908+0621, J1825-1326 and the suggested origin pulsars near the sources have been published. In our previous work, we studied the hadronic $\gamma$-ray spectra of the sources J2226+6057, J1908+0621, J1825-1326 in terms of the Hertzian dipole model of pulsar. In this paper, we investigate the possibility of the leptonic origin of the $\gamma$-ray. We use the Hertzian dipole model to describe the pulsars around the sources. The electrons around the pulsars can be accelerated to PeV by the electromagnetic fields of pulsars. Under the assumption that the initial electrons are uniform distributed in a spherical shell between $10^7$ to $10^9$m around the pulsar, we obtain the energy distribution of electrons. The leptonic $\gamma$-ray spectra can be calculated through inverse Compton scattering processes. The leptonic $\gamma$-ray can roughly conform to the observation of LHAASO.

    ↳ astro-ph.HEhep-phCPC(2023)·0 citations
12. 12*

    Toward minimal composite Higgs models from regular geometries in bottom-up holography

    Daniel Elander🇫🇷 · Ali Fatemiabhari🇬🇧 · Maurizio Piai🇬🇧

    We study a bottom-up, holographic description of a field theory yielding the spontaneous breaking of an approximate SO(5) global symmetry to its SO(4) subgroup. The weakly-coupled, six-dimensional gravity dual has regular geometry. One of the dimensions is compactified on a circle that shrinks smoothly to zero size at a finite value of the holographic direction, hence introducing a physical scale in a way that mimics the effect of confinement in the dual four-dimensional field theory. We study the spectrum of small fluctuations of the bulk fields carrying SO(5) quantum numbers, which can be interpreted as spin-0 and spin-1 bound states in the dual field theory. This work supplements an earlier publication, focused only on the SO(5) singlet states. We explore the parameter space of the theory, paying particular attention to composite states that have the right quantum numbers to be identified as pseudo-Nambu-Goldstone Bosons (PNGBs). We find that in this model the PNGBs are generally heavy, with masses of the same order as other bound states, indicating the presence of a sizeable amount of explicit symmetry breaking in the field theory side. But we also find a qualitatively new, unexpected result. When the dimension of the field-theory operator inducing SO(5) breaking is close to half of the space-time dimensionality, there exists a region of parameter space in which the PNGBs and the lightest scalar are both parametrically light in comparison to all other bound states of the field theory. Although this region is known to yield metastable classical backgrounds, this finding might be relevant to model building in the composite Higgs context.

    ↳ hep-thhep-lathep-phPRD(2023)·24 citations
13. 13*

    $\Lambda$ parameter of the SU(3) Yang-Mills theory from the continuous $\beta$ function

    Anna Hasenfratz🇺🇸 · Curtis Taylor Peterson🇺🇸 · Jake van Sickle🇺🇸 · Oliver Witzel🇩🇪

    Nonperturbative determinations of the renormalization group $\beta$ function are essential to connect lattice results to perturbative predictions of strongly coupled gauge theories and to determine the $\Lambda$ parameter or the strong coupling constant. The continuous $\beta$ function is very well suited for this task because it is applicable both in the weakly coupled deconfined regime as well as the strongly coupled confined regime. Here we report on our results for the $\beta$ function of the pure gauge SU(3) Yang-Mills theory in the gradient flow scheme. Our calculations cover the renormalized coupling range $g_{\text{GF}}^2\sim 1.2-27$, allowing for a direct determination of $\sqrt{8t_0}{\Lambda }_{\overline{\text{MS}}}$ in this system. Our prediction, $\sqrt{8t_0}{\Lambda }_{\overline{\text{MS}}}=0.622(10)$, is in good agreement with recent direct determinations of this quantity.

    ↳ hep-lathep-phPRD(2023)·24 citations
14. 14*

    Canonical Hubble-Tension-Resolving Early Dark Energy Cosmologies are Inconsistent with the Lyman-$\alpha$ Forest

    Samuel Goldstein🇺🇸 · J. Colin Hill🇺🇸 · Vid Iršič🇬🇧 · Blake D. Sherwin🇬🇧

    Current cosmological data exhibit discordance between indirect and some direct inferences of the present-day expansion rate, $H_0$. Early dark energy (EDE), which briefly increases the cosmic expansion rate prior to recombination, is a leading scenario for resolving this "Hubble tension" while preserving a good fit to cosmic microwave background (CMB) data. However, this comes at the cost of changes in parameters that affect structure formation in the late-time universe, including the spectral index of scalar perturbations, $n_s$. Here, we present the first constraints on axion-like EDE using data from the Lyman-$\alpha$ forest, i.e., absorption lines imprinted in background quasar spectra by neutral hydrogen gas along the line of sight. We consider two independent measurements of the one-dimensional Ly$\alpha$ forest flux power spectrum, from the Sloan Digital Sky Survey (SDSS eBOSS) and from the MIKE/HIRES and X-Shooter spectrographs. We combine these with a baseline dataset comprised of Planck CMB data and baryon acoustic oscillation (BAO) measurements. Combining the eBOSS Ly$\alpha$ data with the CMB and BAO dataset reduces the 95% confidence level (CL) upper bound on the maximum fractional contribution of EDE to the cosmic energy budget, $f_{\mathrm{EDE}}$, from 0.07 to 0.03 and constrains $H_0=67.9_{-0.4}^{+0.4}$ km/s/Mpc (68% CL), with maximum a posteriori value $H_0=67.9$ km/s/Mpc. Similar results are obtained for the MIKE/HIRES and X-Shooter Ly$\alpha$ data. Our Ly$\alpha$-based EDE constraints yield $H_0$ values that are in $>4\sigma$ tension with the SH0ES distance-ladder measurement and are driven by the preference of the Ly$\alpha$ forest data for $n_s$ values lower than those required by EDE cosmologies that fit Planck CMB data. Taken at face value, the Ly$\alpha$ forest severely constrains canonical EDE models that could resolve the Hubble tension.

    ↳ astro-ph.COhep-phPRL(2023)·92 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.