Mon·Dec 28, 2015Monday·December 28, 2015

1. 01*

   Jet shapes in pp and Pb-Pb collisions at ALICE

   Leticia Cunqueiro (for the ALICE Collaboration)🇩🇪

   The aim of this work is to explore possible medium modifications to the substructure of inclusive charged jets in Pb-Pb relative to proton-proton collisions by measuring a set of jet shapes. The set of shapes includes the radial moment, $g$, and the momentum dispersion $p_{\mathrm{T}}$D. They provide complementary information on the fragmentation and can help to discriminate between two different scenarios: intra-jet broadening or collimation as a result of jet quenching. \noindent The shapes are measured in Pb--Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV with a constituent cutoff of 0.15 GeV/c and jet resolution $R=$ 0.2. New techniques for background subtraction are applied and a two-dimensional unfolding is performed to correct the shapes to particle level. The corrected jet shapes for jet $p_{\mathrm{T}}$ $40\le p_{\mathrm{T},\mathrm{jet}}\le 60$ GeV/c are presented and discussed. The observed jet shape modifications suggest that the in-medium fragmentation is harder and more collimated than vacuum fragmentation as obtained by a PYTHIA calculation. The PYTHIA calculation is validated with proton-proton data at 7 TeV.

   nucl-exNPA(2016)·24 citations
2. 02*

   Microscopic nuclear structure models and methods : Chiral symmetry, Wobbling motion and $\gamma -$bands

   J. A. Sheikh · G. H. Bhat🇮🇳 · W. A. Dar · S. Jehangir · P. A. Ganai

   A systematic investigation of the nuclear observables related to the triaxial degree of freedom is presented using the multi-quasiparticle triaxial projected shell model (TPSM) approach. These properties correspond to the observation of $\gamma$-bands, chiral doublet bands and the wobbling mode. In the TPSM approach, $\gamma$-bands are built on each quasiparticle configuration and it is demonstrated that some observations in high-spin spectroscopy that have remained unresolved for quite some time could be explained by considering $\gamma$-bands based on two-quasiparticle configurations. It is shown in some Ce-, Nd- and Ge-isotopes that the two observed aligned or s-bands originate from the same intrinsic configuration with one of them as the $\gamma$-band based on a two-quasiparticle configuration. In the present work, we have also performed a detailed study of $\gamma$-bands observed up to the highest spin in Dysposium, Hafnium, Mercury and Uranium isotopes. Furthermore, several measurements related to chiral symmetry breaking and wobbling motion have been reported recently. These phenomena, which are possible only for triaxial nuclei, have been investigated using the TPSM approach. It is shown that doublet bands observed in lighter odd-odd Cs-isotopes can be considered as candidates for chiral symmetry breaking. Transverse wobbling motion recently observed in ${}^{135}$Pr has also been investigated and it is shown that TPSM approach provides a reasonable description of the measured properties.

   ↳ nucl-thnucl-exPhys.Scripta(2016)·47 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.