Wed·Apr 13, 2022Wednesday·April 13, 2022

1. 01*

   Constraining the ${}^{30}$P($p,\gamma {)}^{31}$S reaction rate in ONe novae via the weak, low-energy, $\beta$-delayed proton decay of ${}^{31}$Cl

   T. Budner (1 and 2)🇺🇸 · M. Friedman (1 and 3)🇺🇸 · C. Wrede (1 and 2)🇺🇸 · B. A. Brown (1 and 2)🇺🇸 · J. José (4 and 5)🇪🇸 · D. Pérez-Loureiro (1)🇺🇸 · L. J. Sun (1 and 6)🇺🇸 · J. Surbrook (1 and 2)🇺🇸 · Y. Ayyad (1 and 7)🇪🇸 · D. W. Bardayan (8)🇺🇸 · K. Chae (9)🇰🇷 · A. A. Chen (10)🇨🇦 and 11 other authors

   The ${}^{30}$P$(p,\gamma {)}^{31}$S reaction plays an important role in understanding nucleosynthesis of $A\ge 30$ nuclides in oxygen-neon novae. The Gaseous Detector with Germanium Tagging was used to measure ${}^{31}$Cl $\beta$-delayed proton decay through the key $J^{\pi }=3/2^{+}$, 260-keV resonance. The intensity $I_{\beta p}^{260}=8.3_{-0.9}^{+1.2}\times 10^{-6}$ represents the weakest $\beta$-delayed, charged-particle emission ever measured below 400 keV, resulting in a proton branching ratio of ${\Gamma }_p/\Gamma =2.5_{-0.3}^{+0.4}\times 10^{-4}$. By combining this measurement with shell-model calculations for ${\Gamma }_{\gamma }$ and past work on other resonances, the total ${}^{30}$P$(p,\gamma {)}^{31}$S rate has been determined with reduced uncertainty. The new rate has been used in hydrodynamic simulations to model the composition of nova ejecta, leading to a concrete prediction of ${}^{30}$Si/${}^{28}$Si excesses in presolar nova grains and the calibration of nuclear thermometers.

   nucl-exastro-ph.SRnucl-thPRL(2022)·14 citations
2. 02*

   Chiral symmetry restoration at high matter density observed in pionic atoms

   Takahiro Nishi🇯🇵 · Kenta Itahashi🇯🇵 · DeukSoon Ahn🇯🇵 · Georg P.A. Berg🇺🇸 · Masanori Dozono🇯🇵 · Daijiro Etoh🇯🇵 · Hiroyuki Fujioka🇯🇵 · Naoki Fukuda🇯🇵 · Nobuhisa Fukunishi🇯🇵 · Hans Geissel🇩🇪 · Emma Haettner🇩🇪 · Tadashi Hashimoto🇯🇵 and 36 other authors

   Modern theories of physics tell that the vacuum is not an empty space. Hidden in the vacuum is a structure of anti-quarks $\bar{q}$ and quarks $q$. The $\bar{q}$ and $q$ pair has the same quantum number as the vacuum and condensates in it since the strong interaction of the quantum chromodynamics (QCD) is too strong to leave it empty. The $\bar{q}q$ condensation breaks the chiral symmetry of the vacuum. The expectation value $<\bar{q}q>$ is an order parameter. For higher temperature or higher matter-density, $|<\bar{q}q>|$ decreases reflecting the restoration of the symmetry. In contrast to these clear-cut arguments, experimental evidence is so far limited. First of all, the $\bar{q}q$ is nothing but the vacuum itself. It is neither visible nor perceptible. In this article, we unravel this invisible existence by high precision measurement of pionic atoms, ${\pi }^{-}$-meson-nucleus bound systems. Using the ${\pi }^{-}$ as a probe, we demonstrate that $|<\bar{q}q>|$ is reduced in the nucleus at 58% of the normal nuclear density by a factor of 77 $\pm$ 2% compared with that in the vacuum. This reduction indicates that the chiral symmetry is partially restored due to the extremely high density of the nucleus. The present experimental result clearly exhibits the existence of the hidden structure, the chiral condensate, in the vacuum.

   nucl-exhep-phnucl-thNat.Phys.(2023)·41 citations
3. 03*

   A Study of Complete and Incomplete Reactions of ${}^{12}$C + ${}^{169}$Tm System at Energy Range $\approx$ 4.16-7.5 Mev/Nucleon

   Getahun Kebede

   In this paper an attempt was to measure, the excitation functions of ${}^{169}$Tm(${}^{12}$C, 4n)${}^{177}$Re, ${}^{169}$Tm(${}^{12}$C, 5n)${}^{176}$Re, ${}^{169}$Tm(${}^{12}$C, $\alpha$n)${}^{176}$Ta, ${}^{169}$Tm(${}^{12}$C, $\alpha$2n)${}^{175}$Ta , ${}^{169}$Tm(${}^{12}$C, $\alpha$3n)${}^{174}$Ta , ${}^{169}$Tm(${}^{12}$C, $\alpha$4n)${}^{173}$Ta, and ${}^{169}$Tm(${}^{12}$C, 2$\alpha$2n)${}^{171}$Lu reaction channels populated in the interaction of ${}^{12}$C projectile with ${}^{169}$Tm target were considered in order to investigate the mechanisms of complete and incomplete fusion reactions. The theoretically predicted excitation functions using PACE4 code were compared with the previously measured excitation functions. For non alpha emitting channels cross section values predicted by PACE4 in general were found to be in good agreement with the experimentally measured values. However, for alpha-emitting channels the measured cross-section values were found to be higher than the values predicted by PACE4. The observed disagreement may be credited to projectile break up in the vicinity of nn interaction. Keywords: alpha emitted, CF reaction, excitation functions, heavy ion fusion, incomplete fusion reaction, non alpha emitted

   nucl-exnucl-th0 citations
4. 04*

   Hadron and light nucleus radii from electron scattering

   Zhu-Fang Cui🇨🇳 · Daniele Binosi🇮🇹 · Craig D. Roberts🇨🇳 · Sebastian M. Schmidt🇩🇪

   Conceptually, radii are amongst the simplest Poincaré-invariant properties that can be associated with hadrons and light nuclei. Accurate values of these quantities are necessary so that one may judge the character of putative solutions to the strong interaction problem within the Standard Model. However, limiting their ability to serve in this role, recent measurements and new analyses of older data have revealed uncertainties and imprecisions in the radii of the proton, pion, kaon, and deuteron. In the context of radius measurement using electron + hadron elastic scattering, the past decade has shown that reliable extraction requires complete elimination of bias associated with practitioner-dependent choices of data fitting functions. Different answers to that challenge have been offered; and this perspective describes the statistical Schlessinger point method (SPM), in unifying applications to proton, pion, kaon, and deuteron radii. Grounded in analytic function theory, independent of assumptions about underlying dynamics, free from practitioner-induced bias, and applicable in the same form to diverse systems and observables, the SPM returns an objective expression of the information contained in any data under consideration. Its robust nature and versatility make it suitable for use in many branches of experiment and theory.

   ↳ hep-phhep-exhep-latnucl-ex+1CPC(2022)·35 citations
5. 05*

   Improvement in light collection of a photomultiplier tube using a wavelength-shifting plate

   Austin Mullen🇺🇸 · Oluwatomi Akindele🇺🇸 · Marc Bergevin🇺🇸 · Adam Bernstein🇺🇸 · Steven Dazeley🇺🇸

   Large-volume water-Cherenkov neutrino detectors are a light-starved environment, as each interaction produces only $\sim 50-100$ photons per MeV. As such, maximizing the light collection efficiency of the detector is vital to performance. Since Cherenkov emission is heavily weighted towards the near UV, one method to maximize overall detector light collection without increasing the number of photomultiplier tubes is to couple each tube to a wavelength-shifting plastic plate, thus shifting photon wavelengths to a regime better suited to maximize photomultiplier efficiency and potentially detecting photons that miss the photocathode. To better understand the behavior of such plates, a scan of a rectangular wavelength-shifting plate was performed, and the results were used to calculate the overall percentage improvement in light collection that could be expected for individual PMTs in a large water-Cherenkov detector. Measurements of a 15.1 in. by 11.5 in. wavelength-shifting plate using a 365 nm LED were found to increase overall light collection at the photomultiplier tube by $7.4\pm 0.7\%$. A simulation tuned to reproduce these results was used to predict the behavior of a wavelength shifting plate exposed to Cherenkov spectrum light and found increases in light collection that were linear with edge length, assuming square geometries. These results demonstrate the potential of wavelength-shifting plates to increase the overall light collection efficiency in a large detector.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2022)·4 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.