Tue·Oct 31, 2023Tuesday·October 31, 2023

1. 01*

   Radiative decay branching ratio of the Hoyle state

   Zifeng Luo🇺🇸 · M. Barbui🇺🇸 · J. Bishop🇺🇸 · G. Chubarian · V.Z. Goldberg🇺🇸 · E. Harris🇺🇸 · E. Koshchiy🇺🇸 · C.E. Parker🇺🇸 · M. Roosa🇺🇸 · A. Saastamoinen🇺🇸 · D.P. Scriven🇺🇸 · G.V. Rogachev🇺🇸

   Background: The triple-alpha process is a vital reaction in nuclear astrophysics, characterized by two consecutive reactions [$2\alpha \leftrightarrows {}^8\mathrm{Be}(\alpha ,\gamma ){}^{12}\mathrm{C}$] that drive carbon formation. The second reaction occurs through the Hoyle state, a 7.65 MeV excited state in ${}^{12}\mathrm{C}$ with $J^{\pi }=0^{+}$. The rate of the process depends on the radiative width, which can be determined by measuring the branching ratio for electromagnetic decay. Recent measurements by Kibédi et al. conflicted with the adopted value and resulted in a significant increase of nearly 50\% in this branching ratio, directly affecting the triple-alpha reaction. Purpose: This work aims to utilize charged-particle spectroscopy with magnetic selection as a means to accurately measure the total radiative branching ratio (${\Gamma }_{\mathrm{rad}}/\Gamma$) of the Hoyle state in ${}^{12}\mathrm{C}$. Methods: The Hoyle state in ${}^{12}\mathrm{C}$ was populated via ${}^{12}\mathrm{C}(\alpha ,{\alpha }^{\prime }{)}^{12}{\mathrm{C}}^{\ast }$ inelastic scattering. The scattered $\alpha$ particles were detected using a $\Delta$E-E telescope, while the recoiled ${}^{12}\mathrm{C}$ ions were identified in a magnetic spectrometer. Results: A radiative branching ratio value of ${\Gamma }_{\mathrm{rad}}/\Gamma \times 10^4=4.0\pm 0.3(stat.)\pm 0.16(syst.)$ was obtained. Conclusions: The radiative branching ratio for the Hoyle state obtained in this work is in agreement with the original adopted value. Our result suggests that the proton-$\gamma$-$\gamma$ spectroscopy result reported by Kibédi et al. may be excluded.

   nucl-exastro-ph.SRPRC(2024)·11 citations
2. 02*

   Comparison of Methods to Determine the Fluence of Monoenergetic Neutrons in the Energy Range from 30 keV to 14.8 MeV

   R. Nolte🇩🇪 · B. Lutz

   The primary reference instruments for neutron fluence measurements used at the Physikalisch-Technische Bundesanstalt (PTB) are based on the primary standard for neutron measurements which is the differential neutron-proton scattering cross section. Such instruments require considerable effort for their operation and analysis. Therefore, routine measurements are carried out using a transfer instrument to facilitate the efficient provision of services to customers. A series of measurements was conducted to compare the transfer device to the primary reference instruments and ensure the traceability of neutron fluence measurements. This resulted in an improved characterization of the instrument and new analysis procedures.

   ↳ physics.ins-detnucl-exMetrologia(2024)·1 citation
3. 03*

   Uncertainty Quantification-Enabled Inversion of Nuclear Euclidean Responses

   K. Raghavan · A. Lovato🇺🇸

   Nuclear quantum many-body methods rely on integral transform techniques to infer properties of electroweak response functions from ground-state expectation values. Retrieving the energy dependence of these responses is highly non-trivial, especially for quantum Monte Carlo methods, as it requires inverting the Laplace transform -- a notoriously ill-posed problem. In this work, we propose an artificial neural network architecture suitable for accurate response function reconstruction with precise estimation of the uncertainty of the inversion. We demonstrate the capabilities of this new architecture benchmarking it against Maximum Entropy and previously developed neural network methods designed for a similar task, paying particular attention to its robustness against increasing noise in the input Euclidean responses.

   ↳ nucl-thnucl-exPRC(2024)·5 citations
4. 04*

   Impact of Medium Anisotropy on Quarkonium Dissociation and Regeneration

   Captain R. Singh🇮🇳 · Mohammad Yousuf Jamal · Raghunath Sahoo🇮🇳

   Quarkonium production in ultra-relativistic collisions plays a crucial role in probing the existence of hot QCD matter. This study explores quarkonia states dissociation and regeneration in the hot QCD medium while considering momentum anisotropy. The net quarkonia decay width (${\Gamma }_D$) arises from two essential processes: collisional damping and gluonic dissociation. The quarkonia regeneration includes the transition from octet to singlet states within the anisotropic medium. Our study utilizes a medium-modified potential that incorporates anisotropy via particle distribution functions. This modified potential gives rise to collisional damping for quarkonia due to the surrounding medium, as well as the transition of quarkonia from singlet to octet states due to interactions with gluons. Furthermore, we employ the detailed balance approach to investigate the regeneration of quarkonia within this medium. Our comprehensive analysis spans various temperature settings, transverse momentum values, and anisotropic strengths. Notably, we find that, in addition to medium temperatures and heavy quark transverse momentum, anisotropy significantly influences the dissociation and regeneration of various quarkonia states.

   ↳ hep-phhep-exnucl-exnucl-thEPJC(2024)·9 citations
5. 05*

   Large-scale shell-model study of two-neutrino double-beta decay of ${}^{82}$Se, ${}^{94}$Zr, ${}^{108}$Cd, ${}^{124}$Sn, ${}^{128}$Te, ${}^{130}$Te, ${}^{136}$Xe, and ${}^{150}$Nd

   Deepak Patel🇮🇳 · Praveen C. Srivastava🇮🇳 · V.K.B. Kota🇮🇳 · R. Sahu🇮🇳

   Large-scale shell-model calculations have been performed for the study of two neutrino double-beta ($2\nu \beta \beta$) decay in ${}^{82}$Se, ${}^{94}$Zr, ${}^{108}$Cd, ${}^{124}$Sn, ${}^{128}$Te, ${}^{130}$Te, ${}^{136}$Xe, and ${}^{150}$Nd. We have employed JUN45 interaction to calculate the nuclear matrix element (NME) for $2\nu \beta \beta$ decay in ${}^{82}$Se. In the case of ${}^{94}$Zr, the glekpn effective interaction is used. For ${}^{108}$Cd, we have used a realistic effective interaction derived through the G-matrix approach. In the case of ${}^{124}$Sn, ${}^{128,130}$Te and ${}^{136}$Xe, the sn100pn effective interaction is employed. For ${}^{150}$Nd, we have used KHHE effective interaction based on holes in a ${}^{208}$Pb core. We have extracted the half-lives of these nuclei for the $2\nu \beta \beta$ decay with the help of calculated NME. Our results are consistent with the available experimental half-lives. The variation of cumulative $2\nu \beta \beta$ NME with respect to the excitation energy of the intermediate $1^{+}$ states is also shown, and in all cases, it is ensured that their values are almost saturated. In the present work we have calculated more intermediate $1^{+}$ states as much as possible in comparison to results available in the literature.

   ↳ nucl-thnucl-exNPA(2024)·9 citations
6. 06*

   Transversity PDFs of the proton from lattice QCD with physical quark masses

   Xiang Gao🇺🇸 · Andrew D. Hanlon🇺🇸 · Swagato Mukherjee🇺🇸 · Peter Petreczky🇺🇸 · Qi Shi🇺🇸 · Sergey Syritsyn🇺🇸 · Yong Zhao🇺🇸

   We present a lattice QCD calculation of the transversity isovector- and isoscalar-quark parton distribution functions (PDFs) of the proton utilizing a perturbative matching at next-to-leading-order (NLO) accuracy. Additionally, we determine the isovector and isoscalar tensor charges for the proton. In both calculations, the disconnected contributions to the isoscalar matrix elements have been ignored. The calculations are performed using a single ensemble of $N_f=2+1$ highly-improved staggered quarks simulated with physical-mass quarks and a lattice spacing of $a=0.076$ fm. The Wilson-clover action, with physical quark masses and smeared gauge links obtained from one iteration of hypercubic smearing, is used in the valence sector. Using the NLO operator product expansion, we extract the lowest four to six Mellin moments and the PDFs via a neural network from the matrix elements in the pseudo-PDF approach. In addition, we calculate the PDFs in the quasi-PDF approach with hybrid-scheme renormalization and the recently developed leading-renormalon resummation technique, at NLO with the resummation of leading small-$x$ logarithms.

   ↳ hep-lathep-exhep-phnucl-ex+1PRD(2024)·40 citations
7. 07*

   Eigenvector Continuation and Projection-Based Emulators

   Thomas Duguet🇫🇷 · Andreas Ekström🇸🇪 · Richard J. Furnstahl🇺🇸 · Sebastian König🇺🇸 · Dean Lee🇺🇸

   Eigenvector continuation is a computational method for parametric eigenvalue problems that uses subspace projection with a basis derived from eigenvector snapshots from different parameter sets. It is part of a broader class of subspace-projection techniques called reduced-basis methods. In this colloquium article, we present the development, theory, and applications of eigenvector continuation and projection-based emulators. We introduce the basic concepts, discuss the underlying theory and convergence properties, and present recent applications for quantum systems and future prospects.

   ↳ nucl-thcond-mat.quant-gascs.NAmath.NA+2RMP(2024)·84 citations
8. 08*

   High-pressure xenon gas time projection chamber with scalable design and its performance at around the Q value of ${}^{136}$Xe double-beta decay

   Masashi Yoshida🇯🇵 · Kazuhiro Nakamura🇯🇵 · Shinichi Akiyama🇯🇵 · Sei Ban🇯🇵 · Junya Hikida🇯🇵 · Masanori Hirose🇯🇵 · Atsuko K. Ichikawa🇯🇵 · Yoshihisa Iwashita🇯🇵 · Yukimasa Kashino🇯🇵 · Tatsuya Kikawa🇯🇵 · Akihiro Minamino🇯🇵 · Kentaro Miuchi🇯🇵 and 9 other authors

   We have been developing a high-pressure xenon gas time projection chamber (TPC) to search for neutrinoless double beta ($0\nu \beta \beta$) decay of ${}^{136}$Xe. The unique feature of this TPC is in the detection part of ionization electrons, called ELCC. ELCC is composed of multiple units, and one unit covers 48.5 ${\mathrm{cm}}^2$. A 180 L size prototype detector with 12 units, 672 channels, of ELCC was constructed and operated with 7.6 bar natural xenon gas to evaluate the performance of the detector at around the Q value of ${}^{136}$Xe $0\nu \beta \beta$. The obtained FWHM energy resolution is (0.73 $\pm$ 0.11) % at 1836 keV. This corresponds to (0.60 $\pm$ 0.03) % to (0.70 $\pm$ 0.21) % of energy resolution at the Q value of ${}^{136}Xe$ $0\nu \beta \beta$. This result shows the scalability of the AXEL detector with ELCC while maintaining high energy resolution. Factors determining the energy resolution were quantitatively evaluated and the result indicates further improvement is feasible. Reconstructed track images show distinctive structures at the endpoint of electron tracks, which will be an important feature to distinguish $0\nu \beta \beta$ signals from gamma-ray backgrounds.

   ↳ physics.ins-dethep-exnucl-exPTEP(2024)·2 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.