Wed·Oct 25, 2023Wednesday·October 25, 2023

1. 01*

   Nuclear charge radius of ${}^{26m}$Al and its implication for V${}_{ud}$ in the quark-mixing matrix

   P. Plattner🇨🇭 · E. Wood🇬🇧 · L. Al Ayoubi🇫🇮 · O. Beliuskina🇫🇮 · M.L. Bissell🇬🇧 · K. Blaum🇩🇪 · P. Campbell🇬🇧 · B. Cheal🇬🇧 · R.P. de Groote🇫🇮 · C.S. Devlin🇬🇧 · T. Eronen🇫🇮 · L. Filippin🇧🇪 and 41 other authors

   Collinear laser spectroscopy was performed on the isomer of the aluminium isotope ${}^{26m}$Al. The measured isotope shift to ${}^{27}$Al in the $3s^{2}3p{}^2{P}_{3/2}^{\circ }\to 3s^{2}4s{}^2{S}_{1/2}$ atomic transition enabled the first experimental determination of the nuclear charge radius of ${}^{26m}$Al, resulting in $R_c$=\qty{3.130\pm.015}{\femto\meter}. This differs by 4.5 standard deviations from the extrapolated value used to calculate the isospin-symmetry breaking corrections in the superallowed $\beta$ decay of ${}^{26m}$Al. Its corrected $\mathcal{F}t$ value, important for the estimation of $V_{ud}$ in the CKM matrix, is thus shifted by one standard deviation to \qty{3071.4\pm1.0}{\second}.

   nucl-exPRL(2023)·18 citations
2. 02*

   Quantifying Photoproduction Corrections to J/\psi Measurements in Au+Au and Cu+Cu Collisions at $\sqrt{s_{NN}}=200$ GeV

   Zhejin Liu🇨🇳 · Zebo Tang🇨🇳 · Xin Wu🇨🇳 · Wangmei Zha🇨🇳

   The contribution of J/\psi production from coherent and incoherent photon-induced production is calculated in Au+Au and Cu+Cu collisions at $\sqrt{s_{NN}}=200$ GeV. The yield and nuclear modification factors ($R_{AA}$) contributed by photoproduction are presented as functions of transverse momentum ($p_T$) and centrality at both mid- and forward rapidity. The $R_{AA}$ of J/\psi from photoproduction is found to be as high as 0.6 in the lowest $p_T$ bin ($0<p_T<1$ GeV/$c$) at mid-rapidity in 60-92\% Au+Au collisions. The $R_{AA}$ measured in Au+Au and Cu+Cu collisions at $\sqrt{s_{NN}}=200$ GeV are corrected by subtracting the calculated photoproduction contribution.

   nucl-exPRC(2024)·1 citation
3. 03*

   Recent highlights and prospects on (n,$\gamma$) measurements at the CERN n_TOF facility

   J. Lerendegui-Marco · V. Alcayne · V. Babiano-Suarez · M. Bacak · J. Balibrea-Correa · A. Casanovas · C. Domingo-Pardo · G. de la Fuente · B. Gameiro · F. García-Infantes · I. Ladarescu · E. Musacchio-Gonzalez and 3 other authors

   Neutron capture cross-section measurements are fundamental in the study of the slow neutron capture (s-) process of nucleosynthesis and for the development of innovative nuclear technologies. One of the best suited methods to measure radiative neutron capture (n,$\gamma$) cross sections over the full stellar range of interest for all the applications is the time-of-flight (TOF) technique. Overcoming the current experimental limitations for TOF measurements, in particular on low mass unstable samples, requires the combination of facilities with high instantaneous flux, such as the CERN n_TOF facility, with detection systems with an enhanced detection sensitivity and high counting rate capabilities. This contribution presents a summary about the recent highlights in the field of (n,$\gamma$) measurements at n_TOF. The recent upgrades in the facility and in new detector concepts for (n,\g) measurements are described. Last, an overview is given on the existing limitations and prospects for TOF measurements involving unstable targets and the outlook for activation measurements at the brand new high-flux n_TOF-NEAR station.

   nucl-exastro-ph.IMEPJ Web Conf.(2025)·2 citations
4. 04*

   Effects of nuclear structure and quantum interference on diffractive vector meson production in ultra-peripheral nuclear collisions

   Heikki Mäntysaari🇫🇮 · Farid Salazar🇺🇸 · Björn Schenke🇺🇸 · Chun Shen🇺🇸 · Wenbin Zhao🇺🇸

   We study diffractive vector meson production in ultra-peripheral collisions (UPCs) of heavy nuclei, utilizing a theoretical framework based on the Color Glass Condensate (CGC) formalism. We focus on Au+Au, U+U, Ru+Ru, Zr+Zr, and Pb+Pb collisions, examining the transverse momentum dependence of vector meson production cross-sections and $\cos (2\Delta \Phi )$ asymmetries in the decay product distributions to explore the role of nuclear geometry. The angular modulation is due to the linear polarization of the incoming photons and quantum interference effects. We extract nuclear radii and find them to be consistent with experimental data from the STAR collaboration. The amplitudes of the $\cos (2\Delta \Phi )$ modulation in the cross-section and the extracted radii depend on the nuclear geometry. This dependence is dominated by the geometry-dependent variation of the minimum impact parameter required for ultra-peripheral collisions.

   ↳ nucl-thhep-phnucl-exPRC(2024)·34 citations
5. 05*

   Acceptance effect on the $N_{\mathrm{t}}{N}_{\mathrm{p}}/N_{\mathrm{d}}^2$ ratio of light nuclei coalescence yields as a probe of nucleon density fluctuations

   Michael X. Zhang🇨🇳 · An Gu🇺🇸

   We employ a coalescence model to form deuterons ($\mathrm{d}$), tritons ($\mathrm{t}$) and helium-3 (${}^3\mathrm{He}$) nuclei from a uniformly distributed volume of protons ({\rm p}) and neutrons ({\rm n}). We study the ratio $N_{\mathrm{t}}{N}_{\mathrm{p}}/N_{\mathrm{d}}^2$ of light nuclei yields as a function of the neutron density fluctuations. We investigate the effect of finite transverse momentum ($p_{\mathrm{T}}$) acceptance on the ratio, in particular, the "extrapolation factor" ($f$) for the ratio as functions of the $p_{\mathrm{T}}$ spectral shape and the magnitude of neutron density fluctuations. It is found that $f$ is monotonic in $p_{\mathrm{T}}$ spectra "temperature" parameter and neutron density fluctuation magnitude; variations in the latter are relatively small. We also examine $f$ in realistic simulations using kinematic distributions of protons measured in heavy ion collision data. It is found that $f$ is smooth and monotonic as a function of beam energy. We conclude that extrapolation from limited $p_{\mathrm{T}}$ ranges would not create, enhance, or reduce a local peak of the $N_{\mathrm{t}}{N}_{\mathrm{p}}/N_{\mathrm{d}}^2$ ratio in beam energy. Our study provides a necessary benchmark for light nuclei ratios as a probe of nucleon density fluctuations, an important observable in the search for the critical point of nuclear matter.

   ↳ nucl-thnucl-exNucl.Sci.Tech.(2025)·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.