Mon·Oct 23, 2017Monday·October 23, 2017

1. 01*

   Search for Neutrinoless ${\beta }^{+}EC$ Decay of ${}^{120}$Te with CUORE-0

   CUORE Collaboration: C. Alduino🇺🇸 · K. Alfonso🇺🇸 · D. R. Artusa🇺🇸 · F. T. Avignone III🇺🇸 · O. Azzolini🇮🇹 · G. Bari🇮🇹 · F. Bellini🇮🇹 · G. Benato🇺🇸 · A. Bersani🇮🇹 · M. Biassoni🇮🇹 · A. Branca🇮🇹 · C. Brofferio🇮🇹 and 105 other authors

   We have performed a search for neutrinoless ${\beta }^{+}EC$ decay of ${}^{120}$Te using the final CUORE-0 data release. We describe a new analysis method for the simultaneous fit of signatures with different event topology, and of data subsets with different signal efficiency, obtaining a limit on the half-life of the decay of $T_{1/2}>1.6\cdot 10^{21}$ yr at $90\%$ CI. Combining this with results from Cuoricino, a predecessor experiment, we obtain the strongest limit to date, corresponding to $T_{1/2}>2.7\cdot 10^{21}$ yr at $90\%$ CI.

   nucl-exPRC(2018)·18 citations
2. 02*

   Structure of 55Sc and development of the N=34 subshell closure

   D. Steppenbeck · S. Takeuchi🇯🇵 · N. Aoi🇯🇵 · P. Doornenbal🇯🇵 · M. Matsushita🇯🇵 · H. Wang🇺🇸 · H. Baba🇯🇵 · S. Go🇺🇸 · J. D. Holt🇨🇦 · J. Lee🇯🇵 · K. Matsui🇯🇵 · S. Michimasa🇯🇵 and 13 other authors

   The low-lying structure of ${}^{55}$Sc has been investigated using in-beam $\gamma$-ray spectroscopy with the ${}^9$Be(${}^{56}$Ti,${}^{55}$Sc+$\gamma$)$X$ one-proton removal and ${}^9$Be(${}^{55}$Sc,${}^{55}$Sc+$\gamma$)$X$ inelastic-scattering reactions at the RIKEN Radioactive Isotope Beam Factory. Transitions with energies of 572(4), 695(5), 1539(10), 1730(20), 1854(27), 2091(19), 2452(26), and 3241(39) keV are reported, and a level scheme has been constructed using $\gamma \gamma$ coincidence relationships and $\gamma$-ray relative intensities. The results are compared to large-scale shell-model calculations in the $sd$-$pf$ model space, which account for positive-parity states from proton-hole cross-shell excitations, and to it ab initio shell-model calculations from the in-medium similarity renormalization group that includes three-nucleon forces explicitly. The results of proton-removal reaction theory with the eikonal model approach were adopted to aid identification of positive-parity states in the level scheme; experimental counterparts of theoretical $1/2_1^{+}$ and $3/2_1^{+}$ states are suggested from measured decay patterns. The energy of the first $3/2^{-}$ state, which is sensitive to the neutron shell gap at the Fermi surface, was determined. The result indicates a rapid weakening of the $N=34$ subshell closure in $pf$-shell nuclei at $Z>20$, even when only a single proton occupies the $\pi f_{7/2}$ orbital.

   nucl-exnucl-thPRC(2017)·29 citations
3. 03*

   Incomplete fusion analysis of ${}^7$Li-induced reaction on ${}^{93}$Nb within 3-6.5 MeV/nucleon

   Deepak Kumar · Moumita Maiti

   It is understood from the recent experimental studies that prompt/resonant breakup, and transfer followed by breakup in the weakly bound ${}^{6,7}$Li-induced reactions play a significant role in the complete-incomplete fusion (CF-ICF), suppression/enhancement in the fusion cross section around the Coulomb barrier. Investigation of ICF over CF was done by measuring cross sections of the populated residues in the ${}^7$Li-induced reaction on ${}^{\text{nat}}$Nb target within 3--6.5 MeV/nucleon energy region. Measured excitation functions of different channels were compared with different equilibrium (EQ) and preequilibrium (PEQ) models. The enhancement in cross sections in the proton ($\sim$ 20--30 MeV) and $\alpha$-emitting channels, which may be ascribed to ICF, was observed in the measured energy range when compared to the Hauser-Feshbach and exciton model calculations using EMPIRE, which satisfactorily reproduces the neutron channels, compared to the Weisskopf-Ewing model and Hybrid Monte Carlo calculations. The increment of the incomplete fusion fraction was observed with rising projectile energy.

   nucl-exPRC(2017)·23 citations
4. 04*

   Open Questions in the Understanding of Strangeness Production in HIC -- Experiment Perspective

   C. Blume🇩🇪

   Open questions concerning strangeness production in heavy-ion collisions are discussed with a focus on the experimental aspects. The open points are presented in the context of recent measurements.

   nucl-exEPJ Web Conf.(2018)·6 citations
5. 05*

   Production of ${}^4$He and ${}^4\overline{\text{He}}$ in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV at the LHC

   ALICE Collaboration

   Results on the production of ${}^4\text{He}$ and ${}^4\overline{\text{He}}$ nuclei in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV in the rapidity range $\mid y\mid <1$, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be $\mathrm{d}N/\mathrm{d}{y}_{{}^4\mathrm{He}}=(0.8\pm 0.4(\mathrm{stat})\pm 0.3(\mathrm{syst}))\times 10^{-6}$ and $\mathrm{d}N/\mathrm{d}{y}_{{}^4\overline{\mathrm{He}}}=(1.1\pm 0.4(\mathrm{stat})\pm 0.2(\mathrm{syst}))\times 10^{-6}$, respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature ($T_{\mathrm{chem}}$ = 156 MeV) as for light hadrons. The measured ratio of ${}^4\overline{\mathrm{He}}$/${}^4\mathrm{He}$ is $1.4\pm 0.8(\mathrm{stat})\pm 0.5(\mathrm{syst})$.

   nucl-exhep-exNPA(2018)·143 citations
6. 06*

   Importance of non-flow in mixed-harmonic multi-particle correlations in small collision systems

   Peng Huo🇺🇸 · Katarina Gajdosova🇩🇰 · Jiangyong Jia🇺🇸 · You Zhou🇩🇰

   Recently CMS Collaboration measured mixed-harmonic four-particle azimuthal correlations, known as symmetric cumulants SC(n,m), in pp and pPb collisions, and interpreted the non-zero SC(n,m) as evidence for long-range collectivity in these small collision systems. Using the PYTHIA and HIJING models which do not have genuine long-range collectivity, we show that the CMS results, obtained with standard cumulant method, could be dominated by non-flow effects associated with jet and dijets, especially in $pp$ collisions. We show that the non-flow effects are largely suppressed using the recently proposed subevent cumulant methods by requiring azimuthal correlation between two or more pseudorapidity ranges. We argue that the reanalysis of SC(n,m) using the subevent method in experiments is necessary before they can used to provide further evidences for a long-range multi-particle collectivity and constraints on theoretical models in small collision systems.

   nucl-exhep-phnucl-thPLB(2018)·53 citations
7. 07*

   Fully coupled-channel study of $K^{-}pp$ resonance in a chiral SU(3)-based $\bar{K}N$ potential

   Akinobu Doté🇯🇵 · Takashi Inoue🇯🇵 · Takayuki Myo🇯🇵

   We have investigated the most essential kaonic nucleus "$K^{-}pp$" as a resonant state of the $\bar{K}NN$-$\pi \Sigma N$-$\pi \Lambda N$ coupled channel system using a chiral SU(3)-based $\bar{K}N$ potential. We treat the "$K^{-}pp$" resonance adequately with a fully coupled-channel complex scaling method (full ccCSM). Self-consistency needs to be considered for the energy dependence of the chiral SU(3)-based potential. In the present study, we propose a simple prescription for the treatment of self-consistency, considering the {\it averaged threshold} and {\it averaged binding energy of mesons}. With this prescription, we have successfully found the self-consistent solutions of the "$K^{-}pp$" three-body resonance. The results indicate that the "$K^{-}pp$" system is bound rather shallowly. In particular, when the potential parameters are constrained with the latest $\bar{K}N$ scattering length, the binding energy and half of the mesonic decay width are obtained as $14-50$ MeV and $8-19$ MeV, respectively.

   ↳ nucl-thnucl-exPLB(2018)·33 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.