Mon·Apr 10, 2023Monday·April 10, 2023

1. 01*

   Medium effect on anisotropic surface tension of magnetized quark matter

   Yu-Ying He🇨🇳 · Xin-Jian Wen🇨🇳

   The thermodynamics of finite size quark matter in the quasiparticle model is self-consistently constructed by an effective bag function, which presents the medium effect to the confinement. We obtained completely analytic surface tension in the strong magnetic field with the multiple reflection expansion. The anisotropic structure is demonstrated by the splitting of the longitudinal and transverse surface tensions. The anisotropy of the surface tension could be enhanced by an increase of the magnetic field. The analytical surface tension is modified by an additional term related to the bag function. For strong enough magnetic fields, the increase of the longitudinal surface tension is proportional to the magnetic field.On the contrary, the transverse component vanishes due to all quarks locating in the lowest landau level.

   hep-phPRD(2023)·4 citations
2. 02*

   Resurgent representation of the Adler function in the large-${\beta }_0$ approximation of QCD

   Irinel Caprini🇷🇴

   Using a full resummation of the Adler function in the large-${\beta }_0$ approximation of QCD and a mathematical framework of resurgence suitable for the specific properties of the Borel transform in this particular case, we derive a compact resurgent representation of the QCD Adler function, valid in the whole complex momentum plane. The representation is expressed in terms of the inverse Mellin transform of the Borel function and is analytic in the complex momentum plane, except for cuts along the timelike axis and the Landau region of the spacelike axis. It contains a purely nonperturbative term singular at the origin of the coupling plane, depending on a single real arbitrary constant. We compare the resurgent Adler function derived in this work with a previous determination in a similar framework and use its values in the complex plane for a calculation of the hadronic width of the $\tau$ lepton in the Standard Model.

   hep-phPRD(2023)·3 citations
3. 03*

   Neutrino spin and flavor oscillations in gravitational fields

   Maxim Dvornikov (IZMIRAN)🇷🇺

   We study spin and flavor oscillations of astrophysical neutrinos under the influence of external fields in curved spacetime. First, we consider spin oscillations in case of neutrinos gravitationally scattered off a rotating supermassive black hole surrounded by a thin magnetized accretion disk. We find that the gravitational interaction only does not result in the spin-flip of scattered ultrarelativistic neutrinos. Realistic magnetic fields lead to the significant reduction of the observed flux of neutrinos possessing reasonable magnetic moments. Second, we study neutrino flavor oscillations in stochastic gravitational waves (GWs). We derive the effective Hamiltonian for neutrinos interacting with a plane GW having an arbitrary polarization. Then, we consider stochastic GWs with arbitrary correlators of amplitudes. The equation for the density matrix for neutrino oscillations is solved analytically and the probabilities to detect certain neutrino flavors are derived. We find that the interaction of neutrinos, emitted by a core-collapsing supernova, with the stochastic GW background results in the several percent change of the neutrino fluxes. The observability of the predicted effects is discussed.

   hep-phastro-ph.HEgr-qcPhys.Part.Nucl.Lett.(2023)·9 citations
4. 04*

   EasyScan_HEP: a tool for connecting programs to scan the parameter space of physics models

   Liangliang Shang🇨🇳 · Yang Zhang🇨🇳

   We present an application, EasyScan_HEP, for connecting programs to scan the parameter space of High Energy Physics (HEP) models using various sampling algorithms. We develop EasyScan_HEP according to the principle of flexibility and usability. EasyScan_HEP allows us to connect different programs that calculate physical observables, and apply constraints by one human-readable configuration file. All programs executed through command lines can be connected to EasyScan_HEP by setting input and output parameters of the programs. The current version offers the sampling algorithms of Random, Grid, Markov chain Monte Carlo and MultiNest. We also implement features such as resume function, parallelization, post-processing, and quick analysis.

   hep-phphysics.data-anComput.Phys.Commun.(2024)·25 citations
5. 05*

   Prospects for GPDs extraction with Double DVCS

   K. Deja🇵🇱 · V. Martinez-Fernandez🇵🇱 · B. Pire🇫🇷 · P. Sznajder🇵🇱 · J. Wagner🇵🇱

   Double deeply virtual Compton scattering (DDVCS) is the process where an electron scatters off a nucleon and produces a lepton pair. The main advantage of this process in contrast with deeply virtual and timelike Compton scatterings (DVCS and TCS) is the possibility of directly measuring GPDs for $x\ne \pm \xi$ at leading order in ${\alpha }_s$ (LO). We present a new calculation of the DDVCS amplitude based on the methods developed by R. Kleiss and W. J. Stirling in the 1980s. These techniques produce expressions for amplitudes that are perfectly suited for implementation in numerical simulations. Via the PARTONS software, the correctness of this new formulation has been tested by comparing the DVCS and TCS limits of DDVCS with independent calculations of DVCS and TCS.

   hep-phhep-exnucl-exnucl-thActa Phys.Polon.Supp.(2023)·5 citations
6. 06*

   Medium induced gluon spectrum in dense inhomogeneous matter

   João Barata🇺🇸 · Xoán Mayo López🇪🇸 · Andrey V. Sadofyev🇪🇸 · Carlos A. Salgado🇪🇸

   We calculate the spectrum of gluons sourced by the branching of an energetic quark in the presence of an inhomogeneous QCD medium, focusing on the soft radiation limit. We take into account multiple soft interactions between the partons and matter, treating the transverse variations of its parameters within a gradient expansion. Thus, we derive the general form of the medium induced spectrum up to the first order in gradients, and consider its simplifying limits. In particular, we show that to the leading order in matter gradients and using the harmonic approximation for the scattering potential, the full gluon spectrum can be written in a compact closed form suitable for numerical evaluation. The final gluon transverse momentum tends to align along the anisotropy direction, resulting in a non-trivial azimuthal pattern in the jet substructure.

   hep-phnucl-thPRD(2023)·48 citations
7. 07*

   One-loop fermion-photon vertex in arbitrary gauge and dimensions: a novel approach

   Victor Miguel Banda Guzmán🇲🇽 · Adnan Bashir🇲🇽

   We compute one-loop electron-photon vertex with fully off-shell external momenta in an arbitrary covariant gauge and space-time dimension. There exist numerous efforts in literature where one-loop off-shell vertex is calculated by employing the standard first order Feynman rules in different covariant gauges and space-time dimensions of interest. The tensor structure which decomposes this three-point vertex into the components transverse and longitudinal to the photon momentum gets intertwined in this first order formalism. The Ward-Takahashi identity is explicitly invoked to untangle the two pieces and the results are expressed in a preferred basis of twelve spin-amplitudes. We propose a novel approach based upon an efficient combination of the first and second order formalisms of quantum electrodynamics to compute this one-loop vertex. Among some conspicuous advantages is the fact that this less known second order formalism separates the spin and scalar degrees of freedom of an electron interacting electromagnetically. More noticeably, the longitudinal and transverse contributions naturally disentangle from the onset in our approach. Moreover, this decomposition leads to identities between one-loop scalar Feynman integrals with higher powers in the propagators and shifted space-time dimensions that can be used to prove the Ward-Takahashi identity at one-loop order without the need to evaluate any Feynman integral. Additionally, this natural decomposition allows us to establish the gauge-independence of the Pauli form factor through explicit cancellations of scalar Feynman integrals that depend on the gauge parameter. These cancellations naturally lead to a compact expression for the Pauli form factor in arbitrary dimensions. Wherever necessary and insightful, we make comparisons with earlier works.

   hep-phhep-thnucl-thPRD(2023)·7 citations
8. 08*

   Neutrino flavor oscillations inside matter in conformal coupling models

   Fayçal Hammad🇨🇦 · Parvaneh Sadeghi🇨🇦 · Nicolas Fleury🇨🇦

   We recently studied neutrinos flavor oscillations in vacuum within conformal coupling models. In this paper, we extend that analysis by investigating neutrino flavor oscillations inside matter within a general conformal coupling scenario. We first derive the general formula for the flavor transition probability inside matter in arbitrary static and spherically symmetric spacetimes. The modified resonance formula of the MSW effect is derived and the corresponding adiabaticity parameter of the effect is extracted. An application of our results to the case of two-flavor neutrinos within the well-known chameleon and symmetron conformal coupling models is made.

   hep-phgr-qcPRD(2023)·5 citations
9. 09*

   Chiral Lagrangians for spin-$\frac{1}{2}$ and spin-$\frac{3}{2}$ doubly charmed baryons

   Hao Liu🇨🇳 · Yuan-He Zou🇨🇳 · Yan-Rui Liu🇨🇳 · Shao-Zhou Jiang🇨🇳

   The relativistic chiral Lagrangians for both spin-$\frac{1}{2}$ and spin-$\frac{3}{2}$ doubly charmed baryons are constructed up to the order $\mathcal{O}(p^4)$. From $\mathcal{O}(p^2)$ to $\mathcal{O}(p^4)$, there are 19, 74, and 452 independent terms in the two-flavor case and 25, 112, and 864 independent terms in the three-flavor case. The chiral Lagrangians in the heavy diquark limit are also obtained. From $\mathcal{O}(p^2)$ to $\mathcal{O}(p^4)$, there are 7, 23, and 118 independent terms in the two-flavor case and 8, 31, and 189 independent terms in the three-flavor case. We present the low-energy constant relations between the relativistic case and the case in the heavy diquark limit up to the order $\mathcal{O}(p^3)$. With the heavy diquark-antiquark symmetry, the low-energy constant relations between the doubly charmed baryon case and the heavy-light meson case are also obtained up to the order $\mathcal{O}(p^3)$.

   hep-phPRD(2023)·5 citations
10. 10*

    Revisiting proton-proton fusion in chiral effective field theory

    Bijaya Acharya🇺🇸 · Laura Elisa Marcucci🇮🇹 · Lucas Platter🇺🇸

    We calculate the $S$-factor for proton-proton fusion using chiral effective field theory interactions and currents. By performing order-by-order calculations with a variety of chiral interactions that are regularized and calibrated in different ways, we assess the uncertainty in the $S$-factor from the truncation of the effective field theory expansion and from the sensitivity of the $S$-factor to the short-distance axial current determined from three- and four-nucleon observables. We find that $S(0)=(4.100\pm 0.019(\mathrm{syst})\pm 0.013(\mathrm{stat})\pm 0.008(g_A))\times 10^{-23}{\mathrm{MeV}\mathrm{fm}}^2,$ where the three uncertainties arise, respectively, from the truncation of the effective field theory expansion, use of the two-nucleon axial current fit to few-nucleon observables and variation of the axial coupling constant within the recommended range. The increased value of $S(0)$ compared to previous calculations is mainly driven by an increase in the recommended value for the axial coupling constant and is in agreement with a recent analysis based on pionless effective field theory.

    ↳ nucl-thastro-ph.SRhep-phJ.Phys.G(2023)·6 citations
11. 11*

    Ultraslow PSR J0901-4046 with an ultrahigh magnetic field of $3.2\times 10^{16}$ G

    D. N. Sob'yanin

    The recent discovery of a radio-emitting neutron star with an ultralong spin period of 76 s, PSR J0901-4046, raises a fundamental question on how such a slowly rotating magnetized object can be active in the radio band. A canonical magnetic field of $1.3\times 10^{14}$ G estimated from the pulsar period and its time derivative is wholly insufficient for PSR J0901-4046 to operate. Consideration of a magnetic inclination angle of $10^{\circ }$ estimated from the pulse width gives a higher magnetic field of $1.5\times 10^{15}$ G, which is still an order of magnitude lower than the necessary minimum of $2.5\times 10^{16}$ G following from the death line for radio pulsars with magnetic fields exceeding the critical value $4.4\times 10^{13}$ G. We show that if the observed microstructure of single pulses reflects relativistic beaming, the inferred surface magnetic field appears to be $3.2\times 10^{16}$ G, and without this assumption it is no less than $2.7\times 10^{16}$ G, which explains the existence of radio emission from PSR J0901-4046. This estimation makes PSR J0901-4046 a radio pulsar with the strongest magnetic field known and is a sign that PSR J0901-4046 slows down not by magnetic-dipole radiation, but rather by an electric current of 56 MA, when rotational energy is expended in accelerating charged particles over the polar cap.

    ↳ astro-ph.HEastro-ph.SRhep-phphysics.space-phPRD(2023)·13 citations
12. 12*

    Did the Universe Reheat After Recombination?

    J. Colin Hill🇺🇸 · Boris Bolliet🇬🇧

    A key assumption of the standard cosmological model is that the temperature of the cosmic microwave background (CMB) radiation scales with cosmological redshift $z$ as $T_{\mathrm{CMB}}(z)\propto (1+z)$ at all times after recombination at $z_{\star }\simeq 1090$. However, this assumption has only been precisely tested at $z\lesssim 3$. Here, we consider cosmological models with post-recombination reheating (PRR), in which the CMB monopole temperature abruptly increases due to energy injection after last scattering. Such a scenario can potentially resolve tensions between inferences of the current cosmic expansion rate (the Hubble constant, $H_0$). We consider an explicit model in which a metastable sub-component of dark matter (DM) decays to Standard Model photons, whose spectral energy distribution is assumed to be close to that of the CMB blackbody. A fit to Planck CMB anisotropy, COBE/FIRAS CMB monopole, and SH0ES distance-ladder measurements yields $H_0=71.2\pm 1.1$ km/s/Mpc, matter fluctuation amplitude $S_8=0.774\pm 0.018$, and CMB temperature increase $\delta T_{\mathrm{CMB}}=0.109_{-0.044}^{+0.033}$ K, which is sourced by DM decay at $z\gtrsim 10$. However, matter density constraints from baryon acoustic oscillation and supernovae data highly constrain this scenario, with a joint fit to all datasets yielding $H_0=68.69\pm 0.35$ km/s/Mpc, $S_8=0.8035\pm 0.0081$, and $\delta T_{\mathrm{CMB}}<0.0342$ K (95% CL upper limit). These bounds can be weakened if additional dark relativistic species are present in the early universe, yielding higher $H_0$. We conclude that current data disfavor models with significant PRR solely through its impact on background and linear-theory observables, completely independent of CMB spectral distortion constraints. However, a small amount of such energy injection could play a role in restoring cosmological concordance.

    ↳ astro-ph.COhep-ph5 citations
13. 13*

    Determination of crossing-symmetric $\pi \pi$ scattering amplitudes and the quark mass evolution of the $\sigma$ constrained by lattice QCD

    Arkaitz Rodas🇺🇸 · Jozef J. Dudek🇺🇸 · Robert G. Edwards🇺🇸

    Lattice QCD spectra can be used to constrain partial-wave scattering amplitudes that, while satisfying unitarity, do not have to respect crossing symmetry and analyticity. This becomes a particular problem when extrapolated far from real energies, e.g. in the case of broad resonances like the $\sigma$, leading to large systematic uncertainties in the pole position. In this manuscript, we will show how dispersion relations can implement the additional constraints, using as input lattice--determined $\pi \pi$ partial-wave scattering amplitudes with isospin--0,1,2. We will show that only certain combinations of amplitude parameterizations satisfy all constraints, and that when we restrict to these, the $\sigma$ pole position is determined with minimal systematic uncertainty. The evolution of the now well-constrained $\sigma$ pole with varying light quark mass is presented, showing how it transitions from a bound-state to a broad resonance.

    ↳ hep-lathep-phPRD(2024)·49 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.