Thu·Feb 23, 2023Thursday·February 23, 2023

1. 01*

   Electromagnetic transitions from isobaric analogue states to study nuclear matrix elements for double beta decays and astro-neutrino inverse beta decays

   Hiroyasu Ejiri🇯🇵

   Experimental studies for nuclear matrix elements (NMEs) for neutrinoless double beta decays (DBDs) and astro-neutrino inverse beta decays (IBDs) are crucial for neutrino studies beyond the standard model and the astro neutrino reactions since theoretical model calculations for the NMEs are hard due to the high sensitivities of the NMEs to the models. The NMEs associated with DBDs and IBDs are found for the first time to be studied experimentally by measuring electro-magnetic (gamma) transitions from isobalic analogue states (IASs) of the DBD and IBD nuclei. They are used to help the theoretical model calculations for them. The IAS gamma cross sections and the event rates are estimated to show the feasibility of the experiments.

   nucl-exPRC(2023)·4 citations
2. 02*

   Probing the incompressibility of dense hadronic matter near QCD phase transition in relativistic heavy-ion collisions

   Zhi-Min Wu🇨🇳 · Gao-Chan Yong🇨🇳

   Based on the extended hadronic transport model of relativistic heavy-ion collisions, the incompressibility of dense hadronic matter created in relativistic Au+Au heavy-ion collisions at $\sqrt{s_{NN}}=3$ GeV is studied. By comparing experimental proton directed flow, productions of strange hadrons $\varphi$, $K^{-}$ as well as their ratio $\varphi /K^{-}$, proton high-order cumulants to the model calculations, a large incompressibility of dense hadronic matter is obtained from nucleon observabels while a rather small incompressibility is needed to fit the data of strange hadrons. This may indicate hadronic matter possesses different incompressibilities in different density regions, i.e., the incompressibility may become stiffer from saturation density to a certain baryon density and then turn to soft before reaching hadron-quark phase transition. The study also shows that the incompressibility significantly affects the critical baryon density of hadron-quark phase transition.

   ↳ nucl-thnucl-exPRC(2023)·10 citations
3. 03*

   Measuring the vortex-nucleus pinning force from pulsar glitch rates

   A. Melatos🇦🇺 · M. Millhouse🇺🇸

   Superfluid vortex avalanches are one plausible cause of pulsar glitch activity. If they occur according to a state-dependent Poisson process, the measured long-term glitch rate is determined by the spin-down rate of the stellar crust, ${\dot{\Omega }}_{\mathrm{c}}$, and two phenomenological parameters quantifying the vortex-nucleus pinning force: a crust-superfluid angular velocity lag threshold, $X_{\mathrm{cr}}$, and a reference unpinning rate, ${\lambda }_0$. A Bayesian analysis of 541 glitches in 177 pulsars, with $N_{\mathrm{g}}\ge 1$ events per pulsar, yields $X_{\mathrm{cr}}=0.15_{-0.04}^{+0.09}\mathrm{rad}{\mathrm{s}}^{-1}$, ${\lambda }_{\mathrm{ref}}=7.6_{-2.6}^{+3.7}\times 10^{-8}{\mathrm{s}}^{-1}$, and $a=-0.27_{-0.03}^{+0.04}$ assuming the phenomenological rate law ${\lambda }_0={\lambda }_{\mathrm{ref}}[\tau /(1\mathrm{yr}){]}^a$, where $\tau$ denotes the characteristic spin-down age. The results are broadly similar, whether one includes or excludes quasiperiodic glitch activity, giant glitches, or pulsars with $N_{\mathrm{g}}=0$, up to uncertainties about the completeness of the sample and the total observation time per pulsar. The $X_{\mathrm{cr}}$ and ${\lambda }_0$ estimates are consistent with first-principles calculations based on nuclear theory, e.g. in the semiclassical local density approximation.

   ↳ astro-ph.HEnucl-exnucl-thApJ(2023)·7 citations
4. 04*

   Green's function analysis of the Neutron Lloyd interferometer

   Christian Käding🇦🇹 · Mario Pitschmann🇦🇹 · Hartmut Abele🇦🇹

   The neutron optical Lloyd interferometer can serve as a potent experiment for probing fundamental physics beyond the standard models of particles and cosmology. In this article, we provide a full Green's function analysis of a Lloyd interferometer in the limit that the reflecting mirror extends to the screen. We consider two distinct situations: first, we will review the theoretical case of no external fields being present. Subsequently, we will analyze the case in which a gravitational field is acting on the neutrons. The latter case provides the theory necessary for using a Lloyd interferometer as a probe of gravitational fields.

   ↳ quant-phnucl-exZ.Naturforsch.A(2023)·3 citations
5. 05*

   Hadrons, Superconductor Vortices, and Cosmological Constant

   Keh-Fei Liu🇺🇸

   We explore the roles of the trace anomaly in several hadron properties. We derive the scale invariant expression for the pressure from the gravitational form factors (GFF) of QCD which results in consistent results for the mass and rest energy from the GFF and those from the trace and the Hamiltonian of the energy-momentum tensor (EMT) operators. It is shown that the energy-equilibrium correspondence of hadrons infers an equation of state where the trace anomaly matrix element, emerging from the glue condensate in the vacuum, gives a negative constant pressure that leads to confinement, much like the confinement mechanism for the vortices in type II superconductors where the negative constant pressure is due to the cost of depleting the superconducting condensate. We also note that both the trace anomaly in the QCD energy-momentum tensor and the cosmological constant in Einstein's equation are associated with the metric term which contributes to both energy and pressure. Their difference in terms of the role the pressure plays is discussed. Finally, we note that a lattice calculation of the trace anomaly distribution in the pion has addressed a question about the trace anomaly contribution to the pion mass and suggests that there might be a connection between the conformal symmetry breaking and chiral symmetry breaking in this case.

   ↳ hep-phgr-qchep-lathep-th+1PLB(2024)·20 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.