Thu·Jul 29, 2021Thursday·July 29, 2021

1. 01*

   Transfer reactions as a Tool in Nuclear Astrophysics

   Faïrouz Hammache🇫🇷 · Nicolas de Séréville🇫🇷

   Nuclear reaction rates are one of the most important ingredients in describing how stars evolve. The study of the nuclear reactions involved in different astrophysical sites is thus mandatory to address most questions in nuclear astrophysics. Direct measurements of the cross-sections at stellar energies are very challenging - if at all possible. This is essentially due to the very low cross-sections of the reactions of interest (especially when it involves charged particles), and/or to the radioactive nature of many key nuclei. In order to overcome these difficulties, various indirect methods such as the transfer reaction method at energies above or near the Coulomb barrier are used to measure the spectroscopic properties of the involved compound nucleus that are needed to calculate cross-sections or reaction rates of astrophysical interest. In this review, the basic features of the transfer reaction method and the theoretical concept behind are first discussed, then the method is illustrated with recent performed experimental studies of key reactions in nuclear astrophysics.

   nucl-exFront.in Phys.(2021)·14 citations
2. 02*

   Latest ALICE results on J/$\psi$ photoproduction in ultra-peripheral collisions at the LHC

   T. Herman (for the ALICE Collaboration)🇨🇿

   Ultra-peripheral collisions (UPCs), studied using the ALICE detector, allow us to investigate the low-$x$ behavior of the gluon distribution of the colliding particles. Two new measurements of coherent J/$\psi$ photoproduction cross section from Pb-Pb UPCs at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV are presented: the first measurement of the $|t|$-dependence of the cross section providing a new tool to investigate the transverse gluonic structure at low Bjorken-$x$ and a rapidity-differential measurement at midrapidity allowing us to provide stringent constraints on nuclear gluon shadowing and saturation models. In addition, prospects for heavy vector meson photoproduction measurements in LHC Run 3 and 4 are presented.

   nucl-exhep-exSciPost Phys.Proc.(2022)·0 citations
3. 03*

   Impact of the leading-order short-range nuclear matrix element on the neutrinoless double-beta decay of medium-mass and heavy nuclei

   Lotta Jokiniemi🇪🇸 · Pablo Soriano🇪🇸 · Javier Menéndez🇪🇸

   We evaluate the leading-order short-range nuclear matrix element for the neutrinoless double-beta ($0\nu \beta \beta$) decay of the nuclei most relevant for experiments, including ${}^{76}$Ge, ${}^{100}$Mo, ${}^{130}$Te and ${}^{136}$Xe. In our calculations, performed with the nuclear shell model and proton-neutron quasiparticle random-phase approximation (pnQRPA) methods, we estimate the coupling of this term by the contact charge-independence-breaking coupling of various nuclear Hamiltonians. Our results suggest a significant impact of the short-range matrix element, which is about $15\%-50\%$ and $30\%-80\%$ of the standard $0\nu \beta \beta$-decay long-range matrix element for the shell model and pnQRPA, respectively. Combining the full matrix elements with the results from current $0\nu \beta \beta$-decay experiments we find that, if both matrix elements carry the same sign, these searches move notably toward probing the inverted mass ordering of neutrino masses.

   ↳ nucl-thhep-exhep-phnucl-exPLB(2021)·70 citations
4. 04*

   Beam Particle Identification and Tagging of Incompletely Stripped Heavy Beams with HEIST

   A.K. Anthony🇺🇸 · C.Y. Niu🇺🇸 · R.S. Wang🇺🇸 · J. Wieske · K.W. Brown🇺🇸 · Z. Chajecki🇺🇸 · W.G. Lynch🇺🇸 · Y. Ayyad🇪🇸 · J. Barney🇺🇸 · T. Baumann · D. Bazin🇺🇸 · S. Beceiro-Novo🇪🇸 and 17 other authors

   A challenge preventing successful inverse kinematics measurements with heavy nuclei that are not fully stripped is identifying and tagging the beam particles. For this purpose, the HEavy ISotope Tagger (HEIST) has been developed. HEIST utilizes two micro-channel plate timing detectors to measure time of flight, a multi-sampling ion chamber to measure energy loss, and a high purity Ge detector to identify isomer decays and calibrate the isotope identification system. HEIST has successfully identified ${}^{198}$Pb and other nearby nuclei at energies of about 75 MeV/A. In the experiment discussed, a typical cut containing 89\% of all ${}^{198}$Pb${}^{+80}$ in the beam had a purity of 86\%. We examine the issues of charge state contamination. The observed charge state populations of these ions are presented and are moderately well described by the charge state model GLOBAL.

   ↳ physics.ins-detnucl-exRev.Sci.Instrum.(2022)·3 citations
5. 05*

   First-Generation New Physics in Simplified Models: From Low-Energy Parity Violation to the LHC

   Andreas Crivellin🇨🇭 · Martin Hoferichter🇨🇭 · Matthew Kirk🇮🇹 · Claudio Andrea Manzari🇨🇭 · Luc Schnell🇫🇷

   New-physics (NP) constraints on first-generation quark-lepton interactions are particularly interesting given the large number of complementary processes and observables that have been measured. Recently, first hints for such NP effects have been observed as an apparent deficit in first-row CKM unitarity, known as the Cabibbo angle anomaly, and the CMS excess in $q\bar{q}\to e^{+}{e}^{-}$. Since the same NP would inevitably enter in searches for low-energy parity violation, such as atomic parity violation, parity-violating electron scattering, and coherent neutrino-nucleus scattering, as well as electroweak precision observables, a combined analysis is required to assess the viability of potential NP interpretations. In this article we investigate the interplay between LHC searches, the Cabibbo angle anomaly, electroweak precision observables, and low-energy parity violation by studying all simplified models that give rise to tree-level effects related to interactions between first-generation quarks and leptons. Matching these models onto Standard Model effective field theory, we derive master formulae in terms of the respective Wilson coefficients, perform a complete phenomenological analysis of all available constraints, point out how parity violation can in the future be used to disentangle different NP scenarios, and project the constraints achievable with forthcoming experiments.

   ↳ hep-phhep-exnucl-exnucl-thJHEP(2021)·75 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.