Thu·Dec 8, 2022Thursday·December 8, 2022

1. 01*

   Precision pulse shape simulation for proton detection at the Nab experiment

   Leendert Hayen🇺🇸 · Jin Ha Choi🇺🇸 · Dustin Combs🇺🇸 · R.J. Taylor🇺🇸 · Stefan Baeßler🇺🇸 · Noah Birge🇺🇸 · Leah J. Broussard🇺🇸 · Christopher B. Crawford🇺🇸 · Nadia Fomin🇺🇸 · Michael Gericke🇨🇦 · Francisco Gonzalez🇺🇸 · Aaron Jezghani🇺🇸 and 13 other authors

   The Nab experiment at Oak Ridge National Laboratory, USA, aims to measure the beta-antineutrino angular correlation following neutron $\beta$ decay to an anticipated precision of approximately 0.1\%. The proton momentum is reconstructed through proton time-of-flight measurements, and potential systematic biases in the timing reconstruction due to detector effects must be controlled at the nanosecond level. We present a thorough and detailed semiconductor and quasiparticle transport simulation effort to provide precise pulse shapes, and report on relevant systematic effects and potential measurement schemes.

   nucl-exphysics.ins-detPRC(2023)·8 citations
2. 02*

   Understanding globular cluster abundances through nuclear reactions

   P Adsley🇺🇸 · M Williams🇨🇦 · D S Harrouz🇫🇷 · D P Carrasco-Rojas🇺🇸 · N de Séréville🇫🇷 · F Hammache🇫🇷 · R Longland🇺🇸 · B Bastin🇫🇷 · B Davids🇨🇦 · T Faestermann🇩🇪 · C Fougères🇫🇷 · U Greife🇺🇸 and 15 other authors

   Globular clusters contain multiple stellar populations, with some previous generation of stars polluting the current stars with heavier elements. Understanding the history of globular clusters is helpful in understanding how galaxies merged and evolved and therefore constraining the site or sites of this historic pollution is a priority. The acceptable temperature and density conditions of these polluting sites depend on critical reaction rates. In this paper, three experimental studies helping to constrain astrophysically important reaction rates are briefly discussed.

   nucl-exastro-ph.GAastro-ph.SRnucl-thJ.Phys.Conf.Ser.(2023)·1 citation
3. 03*

   Transfer Reactions in Nuclear Astrophysics

   Philip Adsley🇫🇷

   Transfer reactions are an important tool in nuclear astrophysics. These reactions allow us to identify states in nuclei and to find the corresponding energies, to determine if these states can contribute to astrophysical nuclear reactions and ultimately to determine the strength of that contribution. In this paper, the basic details of how transfer reactions may be used in nuclear astrophysics are set out along with some common pitfalls to avoid.

   nucl-exnucl-thEPJ Web Conf.(2023)·1 citation
4. 04*

   Time-dependent Dirac equation applied to one-proton radioactive emission

   Tomohiro Oishi🇭🇷

   Relativistic energy-density functional (REDF) theory has been developed and utilized for self-consistent meanfield calculations of atomic nuclei. The proton-emitting radioactivity can provide a suitable reference to improve the predicting ability of REDF especially on the proton-drip line. One needs to consider the quantum tunneling effect, which plays an essential role in nucleon-emitting radioactive processes. However, the relativistic quantum tunneling has been less investigated compared with the non-relativistic case. This work is devoted to a theoretical evaluation of one-proton ($1p$) radioactivity based on the relativistic Dirac formalism. For this purpose, I develop the time-dependent (TD) Dirac-spinor calculation to simulate the $1p$ emission. By utilizing the relativistic Hartree-Bogoliubov (RHB) calculation with the DD-PCX parameters, single-proton potentials for the time-dependent Dirac spinor are determined. The TD-Dirac calculation is applied to the $1p$ emissions from the ${}^{37}$Sc and ${}^{39}$Sc nuclei, which can be well approximated as the valence proton and the proton-close-shell cores. The sensitivity of $1p$-emission energy and decaying width to the mass number is demonstrated. Remarkable sensitivity exists due to the size of system, which affects the nuclear part of potentials and energy levels, whereas the Coulomb barrier is common with the same atomic number. The calculated $1p$ energy and decaying lifetime are roughly consistent to the experimental limitation. The present TD-Dirac calculation is expected as applicable widely to proton-rich nuclides in order to improve the REDF by utilizing the $1p$-emission data.

   ↳ nucl-thnucl-exPRC(2023)·5 citations
5. 05*

   Monopoles, spectra of overlap fermions, and eta-prime meson in external magnetic fields

   Masayasu Hasegawa🇷🇺

   The effects of external magnetic fields on monopoles, spectra of the overlap Dirac operator, instantons, and the mass of the eta-prime meson are examined by conducting lattice QCD simulations. The uniform external magnetic fields are applied to gauge field configurations with $N_f$ = 2 + 1 flavor quarks. The bare quark masses are tuned in order to obtain the physical values of the pion mass and of the ratio $\frac{m_s}{m_{u,d}}$. Standard configurations and configurations with applied external magnetic fields are generated in the color confinement and deconfinement phases. The intensity of external magnetic fields varies from $e|B|$ = 0.57 to 1.14 [GeV${}^2$]. To examine the influence of external magnetic fields on monopoles, we first calculate the monopole density, measure the lengths of the monopole loops and compare them with the absolute value of the Polyakov loops. Next, using the generated configurations, we compute the eigenvalues and eigenvectors of the overlap Dirac operator, which preserves exact chiral symmetry. To investigate how external magnetic fields affect the spectra of the overlap Dirac operator, we compute spectral densities, compare fluctuations of the eigenvalues of the overlap Dirac operator with the predictions of random matrix theory, and estimate the number of instantons and anti-instantons from the topological charges. In addition, we analyze smearing effects on these observables and chiral symmetry breaking. Finally, we calculate the decay constant of the pseudoscalar meson, the chiral condensate, and the square mass of the eta-prime meson using the eigenvalues and eigenvectors. We then extrapolate the numerical results in the chiral limit and demonstrate the effects of external magnetic fields on the extrapolation results. This article presents preliminary results.

   ↳ hep-latnucl-exnucl-thTheor.Math.Phys.(2024)·0 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.