Fri·Apr 7, 2017Friday·April 7, 2017

1. 01*

   Evaporation Channel as a Tool to Study Fission Dynamics

   A. Di Nitto · E. Vardaci🇮🇹 · G. La Rana · P.N. Nadtochy🇷🇺 · G. Prete🇮🇹

   The dynamics of the fission process is expected to affect the evaporation residue cross section because of the fission hindrance due to the nuclear viscosity. Systems of intermediate fissility constitute a suitable environment for testing such hypothesis, since they are characterized by evaporation residue cross sections comparable or larger than the fission ones. Observables related to emitted charged particle, due to their relatively high emission probability, can be used to put stringent constraints on models describing the excited nucleus decay and to recognize the effects of fission dynamics. In this work model simulations are compared with the experimental data collected via the ^{32}S + ^{100}Mo reaction at E_{lab}= 200 MeV. By comparing an extended set of evaporation channel observables the limits of the statistical model and the large improvement coming by using a dynamical model are evidenced. The importance of using a large angular covering apparatus to extract the observable is stressed. The opportunity to measure more sensitive observables by a new detection device in operation at LNL are also discussed.

   nucl-exNPA(2018)·16 citations
2. 02*

   Total Absorption Spectroscopy Study of the Beta Decay of ${}^{86}$Br and ${}^{91}$Rb

   S. Rice · A. Algora · J. L. Tain · E. Valencia · J. Agramunt · B. Rubio · W. Gelletly · P.H. Regan · A.-A. Zakari-Issoufou · M. Fallot · A. Porta · J. Rissanen and 27 other authors

   The beta decays of ${}^{86}$Br and ${}^{91}$Rb have been studied using the total absorption spectroscopy technique. The radioactive nuclei were produced at the IGISOL facility in Jyväskylä and further purified using the JYFLTRAP. ${}^{86}$Br and ${}^{91}$Rb are considered to be major contributors to the decay heat in reactors. In addition ${}^{91}$Rb was used as a normalization point in direct measurements of mean gamma energies released in the beta decay of fission products by Rudstam {\it et al.} assuming that this decay was well known from high-resolution measurements. Our results show that both decays were suffering from the {\it Pandemonium} effect and that the results of Rudstam {\it et al.} should be renormalized. The relative impact of the studied decays in the prediction of the decay heat and antineutrino spectrum from reactors has been evaluated.

   nucl-exPRC(2017)·43 citations
3. 03*

   Femtoscopy with identified charged pions in proton-lead collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV with ATLAS

   ATLAS Collaboration

   Bose-Einstein correlations between identified charged pions are measured for $p$+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV using data recorded by the ATLAS detector at the LHC corresponding to a total integrated luminosity of $28$ ${\mathrm{nb}}^{-1}$. Pions are identified using ionization energy loss measured in the pixel detector. Two-particle correlation functions and the extracted source radii are presented as a function of collision centrality as well as the average transverse momentum ($k_{\mathrm{T}}$) and rapidity ($y_{\pi \pi }^{\star }$) of the pair. Pairs are selected with a rapidity $-2<y_{\pi \pi }^{\star }<1$ and with an average transverse momentum $0.1<k_{\mathrm{T}}<0.8$ GeV. The effect of jet fragmentation on the two-particle correlation function is studied, and a method using opposite-charge pair data to constrain its contributions to the measured correlations is described. The measured source sizes are substantially larger in more central collisions and are observed to decrease with increasing pair $k_{\mathrm{T}}$. A correlation of the radii with the local charged-particle density is demonstrated. The scaling of the extracted radii with the mean number of participating nucleons is also used to compare a selection of initial-geometry models. The cross-term $R_{\mathrm{ol}}$ is measured as a function of rapidity, and a nonzero value is observed with $5.1\sigma$ combined significance for $-1<y_{\pi \pi }^{\star }<1$ in the most central events.

   ↳ hep-exnucl-exPRC(2017)·36 citations
4. 04*

   Development of ${}^{100}$Mo-containing scintillating bolometers for a high-sensitivity neutrinoless double-beta decay search

   E. Armengaud🇫🇷 · C. Augier🇫🇷 · A.S. Barabash🇷🇺 · J.W. Beeman🇺🇸 · T.B. Bekker🇷🇺 · F. Bellini🇮🇹 · A. Benoît🇫🇷 · L. Bergé🇫🇷 · T. Bergmann🇩🇪 · J. Billard🇫🇷 · R.S. Boiko🇺🇦 · A. Broniatowski🇫🇷 and 90 other authors

   This paper reports on the development of a technology involving ${}^{100}$Mo-enriched scintillating bolometers, compatible with the goals of CUPID, a proposed next-generation bolometric experiment to search for neutrinoless double-beta decay. Large mass ($\sim$1~kg), high optical quality, radiopure ${}^{100}$Mo-containing zinc and lithium molybdate crystals have been produced and used to develop high performance single detector modules based on 0.2--0.4~kg scintillating bolometers. In particular, the energy resolution of the lithium molybdate detectors near the $Q$-value of the double-beta transition of ${}^{100}$Mo (3034~keV) is 4--6~keV FWHM. The rejection of the $\alpha$-induced dominant background above 2.6~MeV is better than 8$\sigma$. Less than 10~$\mu$Bq/kg activity of ${}^{232}$Th (${}^{228}$Th) and ${}^{226}$Ra in the crystals is ensured by boule recrystallization. The potential of ${}^{100}$Mo-enriched scintillating bolometers to perform high sensitivity double-beta decay searches has been demonstrated with only 10~kg$\times$d exposure: the two neutrino double-beta decay half-life of ${}^{100}$Mo has been measured with the up-to-date highest accuracy as $T_{1/2}$ = [6.90 $\pm$ 0.15(stat.) $\pm$ 0.37(syst.)] $\times$ 10${}^{18}$~yr. Both crystallization and detector technologies favor lithium molybdate, which has been selected for the ongoing construction of the CUPID-0/Mo demonstrator, containing several kg of ${}^{100}$Mo.

   ↳ physics.ins-detnucl-exEPJC(2017)·125 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.