Tue·Feb 1, 2022Tuesday·February 1, 2022

1. 01*

   Interpreting B-anomalies within an extended 331 gauge theory

   Andrea Addazi🇨🇳 · Giulia Ricciardi🇮🇹 · Simone Scarlatella🇮🇹 · Rahul Srivastava🇮🇳 · José W. F. Valle🇪🇸

   In light of the recent $R_{K^{(\ast )}}$ data on neutral current flavour anomalies in $B\to K^{(\ast )}{\ell }^{+}{\ell }^{-}$ decays, we re-examine their quantitative interpretation in terms of an extended 331 gauge theory framework. We achieve this by adding two extra lepton species with novel 331 charges, while ensuring that the model remains anomaly free. In contrast to the canonical 331 models, the gauge charges of the first and second lepton families differ from each other, allowing lepton flavour universality violation. We further expand the model by adding the neutral fermions required to provide an adequate description for small neutrino masses.

   hep-phPRD(2022)·7 citations
2. 02*

   $\mathbf{{\rm Y}}(10753)\to \mathbf{{\rm Y}}(\mathbf{nS}){\pi }^{+}{\pi }^{-}$ decays induced by hadronic loop mechanism

   Zi-Yue Bai🇨🇳 · Yu-Shuai Li🇨🇳 · Qi Huang🇨🇳 · Xiang Liu🇨🇳 · Takayuki Matsuki🇯🇵

   In this work, we investigate the ${\rm Y}(10753)\to {\rm Y}(nS){\pi }^{+}{\pi }^{-}$ ($n=1,2,3$) processes by considering the hadronic loop mechanism, where ${\rm Y}(10753)$ is assigned to a conventional bottomonium in the $4S$-$3D$ mixing scheme. Our results of the concerned processes own considerable branching ratios, which can reach up to the order of magnitude of $10^{-4}-10^{-3}$. We should indicate that the measured ${\Gamma }_{e^{+}{e}^{-}}\times \mathcal{B}[{\rm Y}(10753)\to {\rm Y}(nS){\pi }^{+}{\pi }^{-}]$ values given by Belle can be reproduced well. This fact supports the former bottomonium assignment to the ${\rm Y}(10753)$ in the $4S$-$3D$ mixing scheme. Obviously, it is a good opportunity for the ongoing Belle II experiment if the predicted result in this work can be tested further.

   hep-phhep-exPRD(2022)·35 citations
3. 03*

   Triple-product asymmetry in the radiative two-pion tau decay

   Cheng Chen🇨🇳 · Chun-Gui Duan🇨🇳 · Zhi-Hui Guo🇨🇳

   In this work, we perform a detailed study of the ${\tau }^{-}\to {\pi }^{-}{\pi }^0\gamma \nu$ decay process within the resonance chiral theory. We pay special attention to the triple-product asymmetry in the ${\tau }^{-}\to {\pi }^{-}{\pi }^0\gamma \nu$ process. The minimal resonance chiral Lagrangian and the odd-intrinsic parity resonance operators are simultaneously included to calculate the decay amplitudes. Various invariant-mass distributions in the ${\pi }^{-}{\pi }^0$, ${\pi }^{-}\gamma$ and ${\pi }^0\gamma$ systems are studied and they reveal different resonance dynamics. We further predict the intriguing nonzero triple-product asymmetry distributions, which may provide useful guidelines for future experimental measurements conducted at the Belle-II and super tau-charm facilities.

   hep-phJHEP(2022)·13 citations
4. 04*

   Basis light-front quantization approach to photon

   Sreeraj Nair🇨🇳 · Chandan Mondal🇨🇳 · Xingbo Zhao🇨🇳 · Asmita Mukherjee🇮🇳 · James P. Vary🇺🇸

   We solve for the light-front wave functions (LFWFs) of the physical photon from the eigenvectors of the light-front quantum electrodynamics (QED) Hamiltonian with the aim to determine its bare photon and electron-positron Fock components. We then employ the resulting LFWFs to compute the transverse momentum dependent parton distributions (TMDs) and the generalized parton distributions (GPDs) of the photon. The TMDs are found to be in excellent agreement with the lowest-order perturbative results calculated using the electron-positron quantum fluctuation of the photon. The GPDs are also consistent with the perturbative calculations.

   hep-phPLB(2022)·33 citations
5. 05*

   Smooth Hybrid Inflation with Low Reheat Temperature and Observable Gravity Waves in $SU(5)\times U(1{)}_{\chi }$ Super-GUT

   Waqas Ahmed🇨🇳 · Athanasios Karozas🇬🇷 · George K. Leontaris🇬🇷 · Umer Zubair🇺🇸

   We realize smooth hybrid inflation in the framework of supersymmetric $SU(5)\times U(1{)}_{\chi }\subset SO(10)$ model which provides a natural solution to the monopole problem appearing in the spontaneous symmetry breaking of $SU(5)$. The breaking of $U(1{)}_{\chi }$ symmetry leaves a residual discrete $Z_2$ symmetry, that serves as the MSSM matter parity, realizing the possibility of the lightest supersymmetric particle as a cold dark matter candidate. The $d=5$ proton lifetime for the decay $p\to K^{+}\bar{\nu }$, mediated by color-triplet Higgsinos is found to satisfy current experimental bounds if split-high scale SUSY scenario is employed. We show that with minimal Kähler potential, the soft supersymmetry breaking terms play a vital rôle in bringing the scalar spectral index $n_s$ within the Planck's latest bounds. In a minimal Kähler potential setup, small values of tensor-to-scalar ratio $r\lesssim 3.5\times 10^{-7}$ are obtained, whereas the gravitino mass turns out to be in the range that favors PeV scale SUSY but is not sufficiently high to avoid the $d=5$ proton decay. A non-minimal Kähler potential including higher-order corrections is required to realize successful inflation with central value of scalar spectral index $n_s=0.9655$, large tensor modes $r\lesssim 0.056$ and a low reheat temperature $(3\times 10^6\lesssim T_r\lesssim 6.5\times 10^7)$ GeV consistent with leptogenesis and baryogenesis.

   hep-phgr-qcJCAP(2022)·12 citations
6. 06*

   Reinvestigating the $B$ $\to$ $PV$ decays by including the contributions from ${\varphi }_{B2}$ with the perturbative QCD approach

   Yueling Yang🇨🇳 · Xule Zhao🇨🇳 · Lan Lang🇨🇳 · Jinshu Huang🇨🇳 · Junfeng Sun🇨🇳

   Considering the $B$ mesonic wave function ${\varphi }_{B2}$, the $B$ $\to$ $PV$ decays are restudied at the leading order for three scenarios using the perturbative QCD approach within the standard model, where $P$ $=$ $\pi$ and $K$, and $V$ denotes the ground $SU(3)$ vector mesons. It is found that contributions from ${\varphi }_{B2}$ can enhance most branching ratios, and are helpful for improving the overall consistency of branching ratios between the updated calculations and available data, although there are still several discrepancies between the experimental and theoretical results.

   hep-phhep-exCPC(2022)·6 citations
7. 07*

   Backward timelike Compton scattering to decipher the photon content of the nucleon

   Bernard Pire🇫🇷 · Kirill M. Semenov-Tian-Shansky🇷🇺 · Alisa A. Shaikhutdinova🇷🇺 · Lech Szymanowski🇵🇱

   The exclusive photoproduction off nucleon of a large invariant mass lepton pair in the backward region specified by the small Mandelstam variable $-u$ is discussed in the framework of collinear QCD factorization. The amplitude is factorized in terms of photon-to-nucleon Transition Distribution Amplitudes (TDAs) which encode the photon content of the nucleon. Model estimates of these new non-perturbative objects are described and the corresponding cross sections calculated. The background due to the electromagnetic Bethe-Heitler process is shown to be negligible in the kinematical regime of interest.

   hep-phhep-exnucl-exnucl-thEPJC(2022)·11 citations
8. 08*

   QCD corrections in $tq\gamma$ production at hadron colliders

   Nikolaos Kidonakis🇺🇸 · Nodoka Yamanaka🇯🇵

   We study QCD corrections for the associated production of a single top quark and a photon ($tq\gamma$ production) at hadron colliders. We calculate the NLO cross section at LHC and future collider energies for a variety of kinematical cuts, and we estimate uncertainties from scale dependence and from parton distributions. We also calculate differential distributions in top-quark transverse-momentum and rapidity as well as photon energy. Finally, we study higher-order corrections from soft-gluon emission for this process, and we provide approximate NNLO (aNNLO) results for the cross section and top-quark differential distributions. We also compare our calculations with recent measurements from CMS and ATLAS at the LHC and find that the aNNLO corrections improve the comparison between the data and the Standard Model predictions.

   hep-phEPJC(2022)·14 citations
9. 09*

   Signatures of the spin Hall effect in hot and dense QCD matter

   Baochi Fu🇨🇳 · Longgang Pang🇨🇳 · Huichao Song🇨🇳 · Yi Yin🇨🇳

   The spin Hall effect (SHE) is a generation of spin polarization for moving spin carriers in materials under an external electric field and has been observed in semiconductors, metals, and insulators at or below room temperature. Recent theoretical analyses show that spin Hall current can be induced by the baryon chemical potential gradient which plays the role of the analogous electric field and which becomes sizable in the fireballs created in heavy-ion collisions at beam energy of $\mathcal{O}(10)$~GeV. In this letter, we study this important mechanism for spin polarization generation that has not been systematically explored before and predict the signature of the SHE in those collisions using a (3+1)~D viscous hydrodynamic model MUSIC with AMPT initial condition. We propose to use the second Fourier coefficients of the net spin polarization of Lambda hyperon as sensitive probes to search for the SHE. Those SHE observables show a qualitative difference in both the sign and beam energy dependence for the situations with and without the SHE. Future experimental observation of these distinct qualitative features would provide strong evidence for the existence of the SHE in the hot and dense QCD matter at trillions of degrees.

   hep-phnucl-thPRC(2026)·43 citations
10. 10*

    Search for heavy Majorana neutrinos at electron-proton colliders

    Haiyong Gu🇨🇳 · Kechen Wang🇨🇳

    We develop the search strategy for a heavy Majorana neutrino via the lepton number violation signal process $p{e}^{-}\to {\mu }^{+}jjj$ at future electron-proton colliders. The signal and dominant standard model background events are generated with the fast detector simulation. We apply the pre-selection criteria and perform the multi-variate analysis based on machine-learning to reject the background. Distributions of representative kinematic observables are presented for both signal and background processes and effects on final limits are compared by inputting two different set of observables when performing multi-variate analysis. The 2- and 5-$\sigma$ limits on the mixing parameter $|V_{\ell N}{|}^2$ are predicted for the heavy neutrino mass $m_N$ in the range of 10$-$1000 GeV. At the LHeC (FCC-eh) with an electron beam energy of 60 GeV, a proton beam energy of 7 (50) TeV and an integrated luminosity of 1 (3) ab${}^{-1}$, the mixing parameter $|V_{\ell N}{|}^2$ can be constrained to be below $\sim 3.0(1.0)\times 10^{-6}$ for $m_N$ around $\mathcal{O}(100)$ GeV at 2-$\sigma$ level. The limits are much stronger than the current experiment limits at the LHC for $m_N$ above 30 GeV. The positron signal final state and the effect of long-lived cases of heavy neutrinos are also checked and commented.

    hep-phhep-exPRD(2022)·16 citations
11. 11*

    Coherent photoproduction of heavy quarkonia on nuclei

    B.Z. Kopeliovich🇨🇱 · M. Krelina🇨🇿 · J. Nemchik🇨🇿 · I.K. Potashnikova🇨🇱

    The differential cross section of coherent photo-production of heavy quarkonia on nuclear targets is calculated within the QCD color dipole formalism. The higher-twist nuclear shadowing corresponding to the $\bar{Q}Q$ Fock component of the photon, is calculated including the correlation between dipole orientation $\vec{r}$ and impact parameter of a collision $\vec{b}$, which is related to the transverse momentum transfer via Fourier transform. We also included the leading twist gluon shadowing corresponding to higher Fock components of the photon containing gluons, which have specifically short coherence time, especially for multi-gluon components, even at very high energies. The contribution of such fluctuating gluonic dipole is calculated employing the path-integral technique. Our results are in good agreement with recent ALICE data on charmonium production in ultra-peripheral nuclear collisions.

    hep-phnucl-thPRD(2022)·11 citations
12. 12*

    Nuclear transverse momentum imbalance in the color dipole approach at the LHC regime

    F. G. Ben🇧🇷 · A. V. Giannini🇧🇷 · M. V. T. Machado🇧🇷

    Transverse momentum broadening of a parton propagating through a large nucleus is evaluated in the color dipole approach using different models for the dipole cross section or unintegrated gluon distribution, which lead to different values of the coefficient $C_{\mathcal{F}}(0,s)$. Numerical calculations are compared to data extracted from LHCb and ALICE experiments for nuclear broadening of $J/\psi$. We find that different models which describe the small-$x$ data predict values of $\Delta p_T^2$ that agree reasonably well with experiment, specially for forward rapidity. The centrality dependence was also analysed and the models are consistent with the ALICE measurements.

    hep-phhep-exnucl-thJ.Phys.G(2022)·3 citations
13. 13*

    Improved XTZ masses and mass ratios from Laplace Sum Rules at NLO

    R. Albuquerque (FAT-UERJ, Rio de Janeiro, Br)🇧🇷 · S. Narison (LUPM-CNRS/IN2P3 Montpellier, FR and iHEPMAD, Antananarivo, MG)🇫🇷 · D. Rabetiarivony (iHEPMAD, Antananarivo, MG)🇲🇬

    We present improved estimates of the couplings, masses and mass ratios of the Z_Q,X_Q and T_{QQqq} states using QCD Laplace sum rules (LSR), their ratios R and double ratios DRSR within stability criteria, where the NLO factorized PT QCD corrections are included which is important for giving a meaning on the running MS heavy quark mass used in the analysis. We show that combined R and DRSR can provide more precise results. First, we conclude that the observed X_c(3872) and Z_c(3900) are tetramoles states (superposition of quasi-degenerated molecule and a tetraquark states having (almost) the same coupling to the currents) with the predicted masses: M_{T_{X_c}}=3876(44) MeV and M_{ T_{Z_c}}=3900(42) MeV. In the 2nd part, we focus on the analysis of the four-quark nature of different T_{QQqq'} 1^+ and 0^+ states within the 3_c3_c interpolating currents. The final results are summarized in Table 7. Combined R and DRSR calibrated to the observed X_c(3872) lead to a precise prediction of e.g. M_{T_{cc}^{1^+}}=3886(6) MeV. In a similar way, the DRSR for M_{T_{cc}^{0^+}}/M_{T_{cc}^{1^+}} calibrated to M_{T_{cc}^{1^+}} gives M_{T_{cc}^{0^+}}= 3883(3) MeV. The SU3 breaking ratios M_{T_{ccss}^{0^+}}/ M_{T_{cc}^{0^+}} lead to the improved mass predictions: M_{T_{ccss}^{0^+}}=3988(12) MeV. In the 3rd part, the analysis is extended to the beauty mesons, where we find the tetramole masses : M_{ T_{Z_b}}=10579(99) MeV and M_{X_b}=10545(131) MeV. We also observe that the T^{1^+,0^+}_{bbqq'} states are (almost) stable (within the errors) against strong interactions. In the 4th part, we (critically) review and correct some recent LSR estimates of the T^{1^+,0^+}_{QQqq'} masses. Our results from LSR+DRSR are confronted with the ones from some other approaches (lattices and quark models) in Fig. 25.

    hep-phhep-exhep-latNPA(2022)·18 citations
14. 14*

    Study of finite volume number density fluctuations in the SU(3) Polyakov loop extended Nambu-Jona-Lasinio model for the search of the QCD Critical Point

    A. Sarkar (1)🇮🇳 · P. Deb (2)🇮🇳 · R. Bose (3) ((1) School of Physical Sciences, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh, India (2) Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai, India (3) Department of Physics, Ramakrishna Mission Residential College (Autonomous), Narendrapur, Kolkata, India)🇮🇳

    The critical endpoint (CEP) is a fundamental feature of the Quantum Chromodynamics (QCD) phase diagram, marking the boundary between quark-gluon plasma and hadronic matter. Heavy-ion collision experiments, such as the RHIC Beam Energy Scan, aim to probe the QCD phase diagram by varying collision energy. However, the short-lived nature of produced particles makes direct measurements challenging, necessitating theoretical models. This study explores the impact of density fluctuations on the CEP using the Polyakov-loop enhanced Nambu-Jona-Lasinio (PNJL) model, focusing on quark number densities in both finite and infinite volume systems. Quark number densities, derived from thermodynamic susceptibilities, serve as reliable predictors for the CEP's location. We calculate density fluctuations and normalize them by $T^3$ as functions of temperature and $T/{\mu }_x$ (where x represents light quarks, strange quarks, and baryons), analyzing inflection points and maxima to estimate the critical region. To compare the experimental data, the study has been performed at energies identical to those of the RHIC Beam Energy Scan. The results highlight the influence of finite volume effects on quark density fluctuations, and key indicators of QCD phase transitions, and provide quantitative comparisons with experimental data. This work enhances our understanding of QCD phase structure and supports the ongoing search for the CEP in high-energy heavy-ion collisions, bridging theoretical predictions and experimental observations.

    hep-ph0 citations
15. 15*

    Searching for Chameleon Dark Energy with Mechanical Systems

    J. Betz🇺🇸 · J. Manley🇺🇸 · E. M. Wright🇺🇸 · D. Grin🇺🇸 · S. Singh🇺🇸

    A light scalar field framework of dark energy, sometimes referred to as quintessence, introduces a fifth force between normal matter objects. Screening mechanisms, such as the chameleon model, allow the scalar field to be almost massless on cosmological scales while simultaneously evading laboratory constraints. We explore the ability of mechanical systems available in the near term to directly detect the fifth force associated with chameleon dark energy. We provide analytical expressions for the weakest accessible chameleon model parameters in terms of experimentally tunable variables and apply our analysis to two mechanical systems: levitated microspheres and torsion balances, showing that the current generation of these experiments have the sensitivity to rule out a significant portion of the proposed chameleon parameter space. We also indicate regions of theoretically well-motivated chameleon parameter space to guide future experimental work.

    ↳ astro-ph.COhep-phPRL(2022)·17 citations
16. 16*

    Spin relaxation rate for heavy quarks in weakly coupled QCD plasma

    Masaru Hongo🇺🇸 · Xu-Guang Huang🇨🇳 · Matthias Kaminski🇺🇸 · Mikhail Stephanov🇺🇸 · Ho-Ung Yee🇺🇸

    We compute the relaxation rate of the spin density of heavy quarks in a perturbative QCD plasma to leading-log order in the coupling constant $g$. The spin relaxation rate ${\Gamma }_s$ in spin hydrodynamics is shown to be ${\Gamma }_s\sim g^4\log (1/g)T(T/M{)}^2$ in the heavy-quark limit $T/M\ll 1$, which is smaller than the relaxation rate of other non-hydrodynamic modes by additional powers of $T/M$. We demonstrate three different methods to evaluate the spin relaxation rate: 1) the Green-Kubo formula in the spin hydrodynamic regime, 2) the spin density correlation function in the strict hydrodynamic limit, and 3) quantum kinetic theory of the spin distribution function in momentum space. We highlight the interesting differences between these methods, while they are ultimately connected to each other by the underlying Ward-Takahashi identity for the non-conserved spin density.

    ↳ hep-thhep-phnucl-thJHEP(2022)·48 citations
17. 17*

    Self-Interacting Superfluid Dark Matter Droplets

    V. Delgado🇪🇸 · A. Muñoz Mateo (Univ. La Laguna)🇪🇸

    We assume dark matter to be a cosmological self-gravitating Bose-Einstein condensate of non-relativistic ultralight scalar particles with competing gravitational and repulsive contact interactions and investigate the observational implications of such model. The system is unstable to the formation of stationary self-bound structures that minimize the energy functional. These cosmological superfluid droplets, which are the smallest possible gravitationally bound dark matter structures, exhibit a universal mass profile and a corresponding universal rotation curve. Assuming a hierarchical structure formation scenario where granular dark matter haloes grow around these primordial stationary droplets, the model predicts cored haloes with rotation curves that obey a single universal equation in the inner region ($r\lesssim 1$ kpc). A simultaneous fit to a selection of galaxies from the SPARC database chosen with the sole criterion of being strongly dark matter dominated even within the innermost region, indicates that the observational data are consistent with the presence of a Bose-Einstein condensate of ultralight scalar particles of mass $m\simeq 2.2\times 10^{-22}$ eV c${}^{-2}$ and repulsive self-interactions characterized by a scattering length $a_s\simeq 7.8\times 10^{-77}$ m. Such small self-interactions have profound consequences on cosmological scales. They induce a natural minimum scale length for the size of dark matter structures that makes all cores similar in length ($\sim 1$ kpc) and contributes to lower their central densities.

    ↳ astro-ph.COastro-ph.GAgr-qchep-phMNRAS(2023)·30 citations
18. 18*

    Cosmological model-independent measurement of cosmic curvature using distance sum rule with the help of gravitational waves

    Yan-Jin Wang🇨🇳 · Jing-Zhao Qi🇨🇳 · Bo Wang🇨🇳 · Jing-Fei Zhang🇨🇳 · Jing-Lei Cui🇨🇳 · Xin Zhang🇨🇳

    Although the cosmic curvature has been tightly constrained in the standard cosmological model using observations of cosmic microwave background anisotropies, it is still of great importance to independently measure this key parameter using only late-universe observations in a cosmological model-independent way. The distance sum rule in strong gravitational lensing (SGL) provides such a way, provided that the three distances in the sum rule can be calibrated by other observations. In this paper, we propose that gravitational waves (GWs) can be used to provide the distance calibration in the SGL method, which can avoid the dependence on distance ladder and cover a wider redshift range. Using the simulated GW standard siren observation by the Einstein Telescope as an example, we show that this scheme is feasible and advantageous. We find that $\Delta {\Omega }_k\simeq 0.17$ with the current SGL data, which is slightly more precise than the case of using SN to calibrate. Furthermore, we consider the forthcoming LSST survey that is expected to observe many SGL systems, and we find that about $10^4$ SGL data could provide the precise measurement of $\Delta {\Omega }_k\simeq 10^{-2}$ with the help of GWs. In addition, our results confirm that this method of constraining ${\Omega }_k$ is strongly dependent on lens models. However, obtaining a more accurate phenomenological model for lens galaxies is highly predictable as future massive surveys observe more and more SGL samples, which will significantly improve the constraint of cosmic curvature.

    ↳ astro-ph.COgr-qchep-phMNRAS(2022)·29 citations
19. 19*

    Static electric dipole moment of the francium atom induced by axionlike particle exchange

    D.E. Maison🇷🇺 · L.V. Skripnikov🇷🇺

    The francium atom is considered as a prospective candidate system to search for the T,P-violating electron electric dipole moment [T. Aoki et al Quantum Sci. Technol. 6, 044008 (2021)]. We demonstrate that the same experiment can be used for axionlike particles (ALP) search. For this, we calculate electronic structure constants of ALP-mediated interaction for a wide range of ALP masses. Using the recently updated constraints on the ALP-electron and ALP-nucleon coupling constants, we show that the contribution of considered interactions corresponding to these constraints can give significant contribution to atomic electric dipole moment. Therefore, obtainment of stronger restrictions for ALP characteristics in the francium atom electric dipole moment experiment is possible.

    ↳ physics.atom-phhep-phphysics.chem-phPRA(2022)·7 citations
20. 20*

    Low redshift constraints on scale-covariant models

    C. J. A. P. Martins🇵🇹 · J. S. J. S. Oliveira🇵🇹 · D. A. R. Pinheiro🇵🇹

    The search for a physical model which explains the observed recent acceleration of the universe is a compelling task of modern fundamental cosmology. Recently Fernandes \textit{et al.} presented low redshift observational constraints on a scale invariant model by Maeder. Phenomenologically this can be interpreted as a bimetric theory with a time-dependent cosmological constant. It was shown that a matter density ${\Omega }_m\sim 0.3$ is a poor fit to the data, and the best-fit model would require a fluid with a much smaller density and a significantly positive equation of state parameter. This model is a particular case of an earlier and broader class of models by Canuto \textit{et al.}, which we study here. Specifically, we consider it in two distinct scenarios: as a genuine alternative to $\Lambda$CDM (i.e., without any cosmological constant) and as a parametric extension thereof (where both a cosmological constant and the new mechanism can coexist, and the relative contributions of both are determined by the data). We find that the first scenario can in principle fit the low-redshift data (but a good fit would require values of model parameters, such as the matter equation of state, in conflict with other data), while in the second one the deviation from $\Lambda$CDM is constrained to be small.

    ↳ astro-ph.COgr-qchep-phPhys.Dark Univ.(2022)·2 citations
21. 21*

    Strong CP problem, electric dipole moment, and fate of the axion

    Gerrit Schierholz🇩🇪

    Three hard problems! In this talk I investigate the long-distance properties of quantum chromodynamics in the presence of a topological theta term. This is done on the lattice, using the gradient flow to isolate the long-distance modes in the functional integral measure and tracing it over successive length scales. It turns out that the color fields produced by quarks and gluons are screened, and confinement is lost, for vacuum angles theta > 0, thus providing a natural solution of the strong CP problem. This solution is compatible with recent lattice calculations of the electric dipole moment of the neutron, while it excludes the axion extension of the Standard Model.

    ↳ hep-lathep-phhep-thnucl-thSciPost Phys.Proc.(2022)·2 citations
22. 22*

    Prospects for the detection of the Diffuse Supernova Neutrino Background with the experiments SK-Gd and JUNO

    Yu-Feng Li🇨🇳 · Mark Vagins🇯🇵 · Michael Wurm🇩🇪

    The advent of gadolinium-loaded Super-Kamiokande (SK-Gd) and of the soon-to-start JUNO liquid scintillator detector marks a substantial improvement in the global sensitivity for the Diffuse Supernova Neutrino Background (DSNB). The present article reviews the detector properties most relevant for the DSNB searches in both experiments and estimates the expected signal and background levels. Based on these inputs, we evaluate the sensitivity of both experiments individually and combined. Using a simplified statistical approach, we find that both SK-Gd and JUNO have the potential to reach $>$3$\sigma$ evidence of the DSNB signal within 10 years of measurement. The combined results are likely to enable a $5\sigma$ discovery of the DSNB signal within the next decade.

    ↳ astro-ph.HEastro-ph.IMhep-exhep-ph+1Universe(2022)·24 citations
23. 23*

    Alphabet of one-loop Feynman integrals

    Jiaqi Chen🇨🇳 · Chichuan Ma🇨🇳 · Li Lin Yang🇨🇳

    In this paper, we present the universal structure of the alphabet of one-loop Feynman integrals. The letters in the alphabet are calculated using the Baikov representation with cuts. We consider both convergent and divergent cut integrals and observe that letters in the divergent cases can be easily obtained from convergent cases by applying certain limits. The letters are written as simple expressions in terms of various Gram determinants. The knowledge of the alphabet enables us to easily construct the canonical differential equations of the $d\log$ form and aids in bootstrapping the symbols of the solutions.

    ↳ hep-thhep-phCPC(2022)·17 citations
24. 24*

    An overview of recent STAR jet measurements

    Nihar Ranjan Sahoo (for the STAR collaboration)🇨🇳

    These proceedings discuss recent jet measurements by the STAR experiment at RHIC to study jet substructure in p+p and jet quenching in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 200 GeV. Furthermore, STAR's future plans for precision jet measurements with the upcoming data-taking periods in 2023-2025 are presented.

    ↳ nucl-exhep-exhep-phnucl-thIJMPE(2024)·0 citations
25. 25*

    Effect of Magnetic Field Dissipation on Primordial Li Abundance

    Yini Lu · Motohiko Kusakabe🇨🇳

    The dissipation effects of primordial magnetic fields on the primordial elemental abundances were investigated. When a magnetic field reconnects, its energy is converted to the kinetic energy of charged particles, as observed for solar energetic particles arriving on earth. This accelerates the cosmic background nuclei, and energetic nuclei induce nonthermal reactions. A constraint on the dissipation is derived from a theoretical calculation of the nonthermal reactions during Big Bang nucleosynthesis. We found that observations of the Li and D abundances can be explained if 0.01--0.1 % of the cosmic energy density was utilized for nuclear acceleration after the electron--positron annihilation epoch. Reconnections of such amplitudes of magnetic fields generate outgoing jets, the bulk velocity of which evolves to values appropriate for cosmic ray (CR) nuclear energies of 0.1--1 MeV necessary for successful CR nucleosynthesis. Therefore, acceleration of cosmic background nuclei during the dissipation of primordial magnetic fields is a possible generation mechanism of soft CRs that has been suggested as a solution to the cosmic Li problem. Among the solutions suggested without exotic physics, only the dissipating magnetic field model suggested here explains observations of both low Li and high D abundances. Our results demonstrate that signatures of strong magnetic fields in the early universe have been observed in primordial elemental abundances.

    ↳ astro-ph.COastro-ph.HEhep-phnucl-exApJL(2022)·4 citations
26. 26*

    Searching for mass-spin correlations in the population of gravitational-wave events: the GWTC-3 case study

    G. Franciolini🇮🇹 · P. Pani🇮🇹

    One fundamental goal of the newly born gravitational wave astronomy is discovering the origin of the observed binary black hole mergers. Towards this end, identifying features in the growing wealth of data may help in distinguishing different formation pathways. While large uncertainties still affect the binary formation models, spin-mass relations remain characteristic features of specific classes of channels. By focusing on the effective inspiral spin ${\chi }_{\text{eff}}$, the best reconstructed spin-related merger parameter, we show that current GWTC-3 data support the hypothesis that a fraction of events may display mass-spin correlations similar to one expected by dynamical formation channels of either astrophysical or primordial nature. We quantify the Bayesian evidence in favour of those models, which are substantially preferred when compared to the Gaussian phenomenological model adopted to describe the distribution of ${\chi }_{\text{eff}}$ in the recent LIGO/Virgo/KAGRA population analyses.

    ↳ astro-ph.HEastro-ph.COgr-qchep-phPRD(2022)·61 citations
27. 27*

    Status of the MUonE experiment

    Giovanni Abbiendi🇮🇹

    The MUonE experiment has been proposed to measure the differential cross section of $\mu e$ elastic scattering, by colliding the 160 GeV muons of the CERN M2 beam with atomic electrons of thin target plates. From a very precise measurement of the shape one can achieve a competitive determination of the leading hadronic contribution to the muon magnetic moment, independent from the other existing ones. In preparation for the Test Run with a reduced setup the detector geometry has been optimised. Expected yields for a first physics run with limited statistics are discussed, together with prospects for the assessment of the main systematic uncertainties.

    ↳ physics.ins-dethep-exhep-phPhys.Scripta(2022)·52 citations
28. 28*

    Early time behavior of spatial and momentum anisotropies in kinetic theory across different Knudsen numbers

    Nicolas Borghini🇩🇪 · Marc Borrell🇩🇪 · Hendrik Roch🇩🇪

    We investigate the early time development of the anisotropic transverse flow and spatial eccentricities of a fireball with various particle-based transport approaches using a fixed initial condition. In numerical simulations ranging from the quasi-collisionless case to the hydrodynamic regime, we find that the onset of $v_n$ and of related measures of anisotropic flow can be described with a simple power-law ansatz, with an exponent that depends on the amount of rescatterings in the system. In the few-rescatterings regime we perform semi-analytical calculations, based on a systematic expansion in powers of time and the cross section, which can reproduce the numerical findings.

    ↳ nucl-thhep-phphysics.flu-dynEPJC(2022)·9 citations
29. 29*

    Deuteron Production in Ultra-Relativistic Heavy-Ion Collisions: A Comparison of the Coalescence and the Minimum Spanning Tree Procedure

    Viktar Kireyeu🇷🇺 · Jan Steinheimer🇩🇪 · Jörg Aichelin🇫🇷 · Marcus Bleicher🇩🇪 · Elena Bratkovskaya🇩🇪

    The formation of deuterons in heavy-ion collisions at relativistic energies is investigated by employing two recently advanced models -- the Minimum Spanning Tree (MST) method and the coalescence model by embedding them in the PHQMD and the UrQMD transport approaches. While the coalescence mechanism combines nucleons into deuterons at the kinetic freeze-out hypersurface, the MST identifies the clusters during the different stages of time evolution. We find that both clustering procedures give very similar results for the deuteron observables in the UrQMD as well as in the PHQMD environment. Moreover, the results agree well with the experimental data on deuteron production in Pb+Pb collisions at $\sqrt{s_{NN}}=8.8$ GeV (selected for the comparison of the methods and models in this study). A detailed investigation shows that the coordinate space distribution of the produced deuterons differs from that of the free nucleons and other hadrons. Thus, deuterons are not destroyed by additional rescattering.

    ↳ nucl-thhep-phPRC(2022)·34 citations
30. 30*

    A Critical Assessment of Solutions to the Galaxy Diversity Problem

    Aidan Zentner🇺🇸 · Siddharth Dandavate · Oren Slone🇺🇸 · Mariangela Lisanti🇺🇸

    Galactic rotation curves exhibit a diverse range of inner slopes. Observational data indicates that explaining this diversity may require a mechanism that correlates a galaxy's surface brightness with the central-most region of its dark matter halo. In this work, we compare several concrete models that capture the relevant physics required to explain the galaxy diversity problem. We focus specifically on a Self-Interacting Dark Matter (SIDM) model with an isothermal core and two Cold Dark Matter (CDM) models with/without baryonic feedback. In contrast to the CDM case, the SIDM model can lead to the formation of an isothermal core in the halo, and is also mostly insensitive to baryonic feedback processes, which act on longer time-scales. Using rotation curves from 90 galaxies in the Spitzer Photometry and Accurate Rotation Curves (SPARC) catalog, we perform a comprehensive model comparison that addresses issues of statistical methodology from prior works. The best-fit halo models that we recover are consistent with standard CDM concentration-mass and abundance matching relations. We find that both the SIDM and feedback-affected CDM models are better than a CDM model with no feedback in explaining the rotation curves of low and high surface brightness galaxies in the sample. However, when compared to each other, there is no strong statistical preference for either the SIDM or the feedback-affected CDM halo model as the source of galaxy diversity in the SPARC catalog.

    ↳ astro-ph.GAastro-ph.COhep-phJCAP(2022)·52 citations
31. 31*

    A Double Quantization for 3d Quantum Mechanics with 2d Tiny Extra Window

    Zahra Ghahreman🇮🇷 · Mehdi Dehghani🇮🇷 · Majid Monemzadeh🇮🇷

    We construct a quantum mechanics based on the hypothesis of existing compact extra dimensions for a particle that wants to detect it. By introducing a probability function, we express the transition of particle to the extra 2d window. The general properties of this function has been examined and a length scale for occurrence of particle to extra window is given. By a diverse view point we consider that, the new length scale plays another quantum criteria for another quantization, beside the Planck constant. Canonical quantization of second class constrained systems, is our method for constructing the desired quantum mechanics, in which in it the probability function enters in the structure of second class constraints. This import the phenomena of extra dimension to the 3d quantum mechanics, effectively. Some aspects of this effective double quantum theory are mentioned, which one may investigate them more focused to experience extra dimension quantum mechanically in contrast to field theoretic sights. Specially, we try to make solutions for wave function and spectrum of the free particle, by Frobenius prescription for solving linear differential equations. In this context, the length scale of extra dimension characterizes the singularity of the wave equation at the boundary which tiny extra window connected to 3d space.

    ↳ quant-phhep-phhep-th0 citations
32. 32*

    The Diffuse Supernova Neutrino Background in the Standard and Double Collapse Models

    Alexander Libanov🇷🇺 · Andrey Sharofeev🇷🇺

    The diffuse supernova neutrino background (DSNB) is a powerful future tool to constrain core-collapse explosion mechanisms without observation of a nearby event, and the corresponding signal has been calculated for a variety of collapse models. For Supernova (SN) 1987A, a peculiar double neutrino burst was detected, but models for the double collapse have never been studied in the DSNB context. Here, we fill this gap and compare the DSNB signal expected in the Standard Collapse (SC) and the Double Collapse (DC) models in various future detectors, including Hyper-Kamiokande, JUNO, DUNE and the Large Baksan Neutrino Telescope (LBNT). We calculate the spectra of diffuse neutrinos and antineutrinos in the DC model and determine the rate of registered events as a function of energy of the detected particle, taking into account detector parameters. For each detector, we estimate the corresponding uncertainties and the background and compare the signals expected for the SC and DC models. We conclude that the combination of DUNE and LBNT data will have the highest sensitivity to discriminate between the SC and DC models.

    ↳ astro-ph.HEhep-phPRD(2022)·5 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.