Thu·Feb 7, 2019Thursday·February 7, 2019

1. 01*

   Comparison of AMD calculations with experimental data for peripheral collisions of 93Nb+93Nb,116Sn at 38 MeV/nucleon

   S.Piantelli🇮🇹 · A.Olmi🇮🇹 · P.R.Maurenzig · A.Ono🇯🇵 · M.Bini🇮🇹 · G.Casini🇮🇹 · G.Pasquali🇮🇹 · A.Mangiarotti🇵🇹 · G.Poggi🇮🇹 · A.A.Stefanini🇮🇹 · S.Barlini🇮🇹 · A.Camaiani🇮🇹 and 4 other authors

   Experimental data concerning binary events in peripheral collisions for the systems 93Nb+93Nb and 93Nb+116Sn at 38 MeV/nucleon, collected with the Fiasco setup, are compared with calculations performed with the dynamic code AMD, coupled with the statistical code Gemini used as an afterburner. The comparison focuses on the properties of the quasiprojectile (QP) and on the total multiplicities of the emitted light charged particles. A good reproduction of the average mass ratio, charge Z and c.m. angle of the QP is obtained in the examined impact parameter range (b~7-12 fm). Concerning the light charged particles, a general agreement is found for the total emitted charge, while some discrepancy remains for the multiplicities of the various species, especially for the protons which are always overestimated by the calculations.

   nucl-exnucl-thPRC(2019)·26 citations
2. 02*

   Approaching the Gamow window with stored ions: Direct measurement of ${}^{124}$Xe(p,$\gamma$) in the ESR storage ring

   J. Glorius🇩🇪 · C. Langer🇩🇪 · Z. Slavkovská🇩🇪 · L. Bott🇩🇪 · C. Brandau🇩🇪 · B. Brückner🇩🇪 · K. Blaum🇩🇪 · X. Chen🇨🇳 · S. Dababneh🇯🇴 · T. Davinson🇬🇧 · P. Erbacher🇩🇪 · S. Fiebiger🇩🇪 and 54 other authors

   We report the first measurement of low-energy proton-capture cross sections of ${}^{124}$Xe in a heavy ion storage ring. ${}^{124}$Xe${}^{54+}$ ions of five different beam energies between 5.5 AMeV and 8 AMeV were stored to collide with a windowless hydrogen target. The ${}^{125}$Cs reaction products were directly detected. The interaction energies are located on the high energy tail of the Gamow window for hot, explosive scenarios such as supernovae and X-ray binaries. The results serve as an important test of predicted astrophysical reaction rates in this mass range. Good agreement in the prediction of the astrophysically important proton width at low energy is found, with only a 30% difference between measurement and theory. Larger deviations are found above the neutron emission threshold, where also neutron- and $\gamma$-widths significantly impact the cross sections. The newly established experimental method is a very powerful tool to investigate nuclear reactions on rare ion beams at low center-of-mass energies.

   nucl-exPRL(2019)·51 citations
3. 03*

   A Search for Neutrinoless Double-Beta Decay in ${}^{76}$Ge with 26 kg-yr of Exposure from the MAJORANA DEMONSTRATOR

   S.I. Alvis · I.J. Arnquist · F.T. Avignone III · A.S. Barabash · C.J. Barton · V. Basu · F.E. Bertrand · B. Bos · M. Busch · M. Buuck · T.S. Caldwell · Y-D. Chan and 52 other authors

   The MAJORANA Collaboration is operating an array of high purity Ge detectors to search for the neutrinoless double-beta decay of ${}^{76}$Ge. The MAJORANA DEMONSTRATOR consists of 44.1 kg of Ge detectors (29.7 kg enriched to 88% in ${}^{76}$Ge) split between two modules constructed from ultra-clean materials. Both modules are contained in a low-background shield at the Sanford Underground Research Facility in Lead, South Dakota. We present updated results on the search for neutrinoless double-beta decay in ${}^{76}$Ge with $26.0\pm 0.5$ kg-yr of enriched exposure. With the DEMONSTRATOR's unprecedented energy resolution of 2.53 keV FWHM at $Q_{\beta \beta }$, we observe one event in the region of interest with 0.65 events expected from the estimated background, resulting in a lower limit on the ${}^{76}$Ge neutrinoless double-beta decay half-life of $2.7\times 10^{25}$ yr (90% CL) with a median sensitivity of $4.8\times 10^{25}$ yr (90% CL). Depending on the matrix elements used, a 90% CL upper limit on the effective Majorana neutrino mass in the range of 200-433 meV is obtained. The measured background in the low-background configurations is $11.9\pm 2.0$ counts/(FWHM t yr).

   nucl-exhep-exPRC(2019)·196 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.