Tue·Apr 2, 2024Tuesday·April 2, 2024

1. 01*

   A new approach for deducing rms proton radii from charge-changing reactions of neutron-rich nuclei and the reaction-target dependence

   J.-C. Zhang · B.-H. Sun · I. Tanihata · R. Kanungo · C. Scheidenberger · S. Terashima · Feng Wang · F. Ameil · J. Atkinson · Y. Ayyad · S. Bagchi · D. Cortina-Gil and 26 other authors

   We report the charge-changing cross sections (${\sigma }_{\text{cc}}$) of 24 $p$-shell nuclides on both hydrogen and carbon at about 900$A$ MeV, of which ${}^{8,9}$Li, ${}^{10\text{textendash}12}$Be, ${}^{10,14,15}$B, ${}^{14,15,17\text{textendash}22}$N and ${}^{16}$O on hydrogen and ${}^{8,9}$Li on carbon are for the first time. Benefiting from the data set,we found a new and robust relationship between the scaling factor of the Glauber model calculations and the separation energies of the nuclei of interest on both targets.This allows us to deduce proton radii ($R_p$) for the first time from the cross sections on hydrogen. Nearly identical $R_p$ values are deduced from both target data for the neutron-rich carbon isotopes, however, the $R_p$ from the hydrogen target is systematically smaller in the neutron-rich nitrogen isotopes.This calls for further experimental and theoretical investigations.

   nucl-exnucl-thSci.Bull.(2024)·20 citations
2. 02*

   Energy, strength, and alpha width measurements of $E_{c.m.}=1323$ and $1487$ keV resonances in ${}^{15}$N($\alpha ,\gamma$)${}^{19}$F

   R. Fang🇺🇸 · J. Görres · R. J. deBoer🇺🇸 · S. Moylan🇺🇸 · A. Sanchez · T. L. Bailey · S. Carmichael · J. Koros🇺🇸 · K. Lee🇰🇷 · K. Manukyan🇺🇸 · M. Matney🇺🇸 · J. P. McDonaugh and 4 other authors

   The ${}^{15}$N($\alpha ,\gamma$)${}^{19}$F reaction produces ${}^{19}$F in asymptotic giant branch (AGB) stars, where the low energy tails of two resonances at $E_{c.m.}=1323\pm 2$ and $1487\pm 1.7$ keV are estimated to contribute about $30\%$ of the total reaction rate in these environments. However, recent measurements have shown discrepancies in the energies, the strengths, and the corresponding alpha widths of these two resonances, resulting in an increase in the systematic uncertainty of the extrapolated cross section to helium burning energies. With this motivation, we have undertaken new measurements of the ${}^{15}$N$(\alpha ,\gamma {)}^{19}$F at the University of Notre Dame Nuclear Science Laboratory. The setup consisted of an alpha particle beam impinged on a solid Ti${}^{15}$N target with gamma-ray spectroscopy accomplished using a high purity germanium detector. Using the Doppler corrected gamma-ray energies, we confirmed the lower resonance energy to be $1321.6\pm 0.6$ keV and found a value for the higher one of $1479.4\pm 0.6$ keV that is more consistent with those found from previous elastic scattering studies. We found that the resonance strengths for both were consistent with most values found in the literature, but a larger alpha width has been recommended for the $E_{c.m.}=1487$ keV resonance. The larger alpha width suggests a reaction rate increase of about $15\%$ at temperatures $T<0.1$ GK relevant to low mass AGB stars. The impact of the increased reaction rate requires further investigations.

   nucl-exPRC(2024)·2 citations
3. 03*

   Thermal production of charm quarks in relativistic heavy-ion collisions

   Taesoo Song🇩🇪 · Ilia Grishmanovskii🇩🇪 · Olga Soloveva🇩🇪 · Elena Bratkovskaya🇩🇪

   We investigate the thermal production of charm quarks in the strongly interacting quark-gluon plasma (sQGP) created in heavy-ion collisions at relativistic energies. Our study is based on the off-shell parton-hadron-string dynamics (PHSD) transport approach describing the full time evolution of heavy-ion collisions on a microscopic basis with hadronic and partonic degrees of freedom. The sQGP is realized within the effective dynamical quasi-particle model (DQPM) which is adjusted to reproduce the lattice QCD results for the thermodynamic observables of the sQGP. Relying on the fact that the DQPM successfully describes the spatial diffusion coefficients $D_s$ from the lQCD, which control the interaction of charm quarks with thermal partons (expressed in terms of strongly interacting off-shell quasiparticles), we evaluate the production of charm quark pairs through the rotation of Feynman diagrams such that the incoming charm quark and outgoing light parton in elastic scattering diagrams are exchanged. The charm quark annihilation is realized by detailed balance. We find that the number of produced thermal charm quark pairs strongly depends on the charm quark mass in the QGP. While for the heavy charm quarks of mass $m_c=1.8$ GeV it is subdominant compared to the primary charm production by binary nucleon-nucleon collisions at RHIC and LHC energies, the numbers of primary and thermal charm quarks become comparable for a smaller (bare) $m_c=1.2$ GeV. Compared with the experimental data on the $R_{\mathrm{AA}}$ of $D$-mesons in heavy-ion collisions at RHIC and LHC energies, it is more favorable for charm quarks in the QGP to gain additional mass due to thermal effects rather than to have a low bare mass.

   ↳ nucl-thhep-phnucl-exPRC(2024)·14 citations
4. 04*

   Total Gluon Helicity from Lattice without Effective Theory Matching

   Zhuoyi Pang🇨🇳 · Fei Yao🇨🇳 · Jian-Hui Zhang🇨🇳

   We propose two approaches for extracting the total gluon helicity contribution to proton spin from lattice QCD, one from local operator matrix elements in a fixed gauge accessible on lattice with feasible renormalization, and the other from gauge-invariant nonlocal gluon correlators. Neither of these approaches requires a matching procedure when converted to the MS scheme. Our proposal resolves a long-standing inconsistency in the literature regarding lattice calculations of the total gluon helicity, and has the potential to greatly facilitate these calculations.

   ↳ hep-phhep-latnucl-exnucl-thJHEP(2024)·6 citations
5. 05*

   Towards CRES-Based Non-destructive Electron Momentum Estimation for the PTOLEMY Relic Neutrino Detector

   Yuno Iwasaki · Andi Tan🇺🇸 · Christopher G. Tully (PTOLEMY Collaboration)🇺🇸

   The novel electron spectrometry method proposed by the PTOLEMY relic neutrino experiment requires a real-time, non-destructive estimate of the parallel and transverse momentum splits of tritium $\beta$-decay electrons. The collaboration has proposed to obtain this estimate using cyclotron-radiation emission spectroscopy (CRES), in which the kinetic energy of a charged particle is determined by measuring the relativistic frequency shift of the cyclotron radiation emitted by the particle in a magnetic field. However, no suitable approach to extract this information in a non-destructive manner has been developed to date. In this paper, we characterize the performance of a configuration that can be feasibly integrated directly into the existing design for the transverse drift filter proposed by the PTOLEMY collaboration. We study a geometry incorporating a cavity resonator to enhance a $\sim \mathcal{O}(1)\mathrm{fW}$ cyclotron radiation signal and derive key features of the expected observed radiation specific to our radio-frequency (RF) tracking configuration. We estimate the performance of our design using electromagnetic simulations and propose a general signal reconstruction algorithm capable of matching an observed signal to electron kinematic parameters. The projected signal-to-noise ratio (SNR) of this technique suggests that a non-destructive RF tracking system based on an array of these components as building blocks is applicable for extracting the kinematic parameters of tritium endpoint electrons to the precision required for the PTOLEMY experiment.

   ↳ physics.ins-detnucl-ex10 citations
6. 06*

   Farside-dominant quasinuclear rainbow in refractive $\alpha$+$\alpha$ scattering

   S. Ohkubo

   $\alpha$+$\alpha$ scattering has a long history since the first experiment by Rutherford and Chadwick in 1927 and has been studied thoroughly experimentally and theoretically. However, $\alpha$+$\alpha$ scattering has never been paid attention from the viewpoint of refractive scattering. I have successfully analyzed the experimental angular distributions in $\alpha$+$\alpha$ scattering systematically over a wide range of incident energies $E_L$=53.4 - 280 MeV using a phenomenological optical model with a deep real potential. The existence of a farside-dominant quasinuclear rainbow with no well-defined rainbow angle and no supernumerary bow in the lit side followed by the shadow, which is not a genuine rainbow but a refractive scattering from a marginally small droplet at high energies, is found for the first time in $\alpha$+$\alpha$ scattering. The refraction due to the deep potentials with an attractive core at short distances are discussed from the viewpoint of the Luneburg. The deep vs shallow problem of the potential and the nuclear rainbow scattering in inelastic channels are also discussed.

   ↳ nucl-thnucl-exPRC(2024)·1 citation

* 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.