Wed·Dec 9, 2015Wednesday·December 9, 2015

1. 01*

   ALICE Upgrades: Plans and Potentials

   Raphael Tieulent (for the ALICE Collaboration)🇺🇸

   The ALICE collaboration consolidated and completed the installation of current detectors during LS1 with the aim to accumulate 1 nb${}^{-1}$ of Pb-Pb collisions during Run 2 corresponding to about 10 times the Run 1 integrated luminosity. In parallel, the ALICE experiment has a rich detector upgrade programme scheduled during the second LHC long shutdown (LS2, 2018-2019) in order to fully exploit the LHC Runs 3 and 4. The main objectives of this programme are: improving the tracking precision and enabling the read-out of all Pb-Pb interactions at a rate of up to 50 kHz, with the goal to record an integrated luminosity of 10 nb${}^{-1}$ after LS2 in minimum-bias trigger mode. This sample would represent an increase by a factor of one hundred with respect to the minimum-bias sample expected during Run 2. The implementation of this upgrade programme, foreseen in LS2, includes: a new low-material Inner Tracking System at central rapidity with a forward rapidity extension to add vertexing capabilities to the current Muon Spectrometer; the replacement of the Time Projection Chamber wire chambers with gas electron multiplier readout; a new readout electronics for most of the detectors and an updated trigger system; a new set of forward trigger detectors and a new integrated online-offline system. High-precision measurements of open heavy-flavour, quarkonia and low-mass dilepton production are the major physics goals of the ALICE upgrade programme. Thanks to the new inner tracking system, the measurements of the nuclear modification factor and elliptic flow of several species of charm and beauty mesons and baryons will be extended to zero or close to zero $p_T$. At forward rapidity, the new silicon based tracker (MFT) will allow prompt J/$\psi$ to be separated from displaced J/$\psi$ from B decays down to zero $p_T$ as well as single muons to be separated from charm and beauty hadron decays.

   nucl-ex4 citations
2. 02*

   The ${}^{63}$Ni(n,$\gamma$) cross section measured with DANCE

   M. Weigand🇩🇪 · T.A. Bredeweg🇺🇸 · A. Couture🇺🇸 · K. Göbel🇩🇪 · T. Heftrich🇩🇪 · M. Jandel · F. Käppeler🇩🇪 · C. Lederer🇩🇪 · N. Kivel🇩🇪 · G. Korschinek🇩🇪 · M. Krticka🇨🇿 · J.M. O'Donnell🇺🇸 and 6 other authors

   The neutron capture cross section of the s-process branch nucleus ${}^{63}$Ni affects the abundances of other nuclei in its region, especially ${}^{63}$Cu and ${}^{64}$Zn. In order to determine the energy dependent neutron capture cross section in the astrophysical energy region, an experiment at the Los Alamos National Laboratory has been performed using the calorimetric 4$\pi$ BaF${}_2$ array DANCE. The (n,$\gamma$) cross section of ${}^{63}$Ni has been determined relative to the well known ${}^{197}$Au standard with uncertainties below 15%. Various ${}^{63}$Ni resonances have been identified based on the Q-value. Furthermore, the s-process sensitivity of the new values was analyzed with the new network calculation tool NETZ.

   nucl-exPRC(2015)·23 citations
3. 03*

   Two-Neutron Sequential Decay of ${}^{24}$O

   M.D. Jones🇺🇸 · N. Frank🇺🇸 · T. Baumann🇺🇸 · J. Brett · J. Bullaro · P.A. DeYoung🇺🇸 · J.E. Finck🇺🇸 · K. Hammerton · J. Hinnefeld · Z. Kohley🇺🇸 · A.N. Kuchera🇺🇸 · J. Pereira🇺🇸 and 9 other authors

   A two-neutron unbound excited state of ${}^{24}$O was populated through a (d,d') reaction at 83.4 MeV/nucleon. A state at $E=715\pm 110$ (stat) $\pm 45$ (sys) keV with a width of $\Gamma <2$ MeV was observed above the two-neutron separation energy placing it at 7.65 $\pm$ 0.2 MeV with respect to the ground state. Three-body correlations for the decay of ${}^{24}$O $\to$ ${}^{22}$O + $2n$ show clear evidence for a sequential decay through an intermediate state in ${}^{23}$O. Neither a di-neutron nor phase-space model for the three-body breakup were able to describe these correlations.

   nucl-exPRC(2015)·22 citations
4. 04*

   Hydrodynamic simulations of relativistic heavy-ion collisions with different lattice QCD calculations of the equation of state

   J. Scott Moreland🇺🇸 · Ron A. Soltz🇺🇸

   Hydrodynamic calculations of ultra-relativistic heavy ion collisions are performed using the iEBE-VISHNU 2+1D code with fluctuating initial conditions and three different parameterizations of the Lattice QCD equations of state: continuum extrapolations for stout and HISQ/tree actions, as well as the s95p-v1 parameterization based upon calculations using the p4 action. All parameterizations are matched to a hadron resonance gas equation of state at T = 155 MeV, at which point the calculations are continued using the UrQMD hadronic cascade. Calculations for $\sqrt{s_{NN}}=200$ GeV Au+Au collisions in three centrality classes are compared to experimental data for final state particle spectra and anisotropic flow coefficients $v_2$ and $v_3$ as well as for pion HBT radii. Experimental observables for the stout and HISQ/tree equations of state are observed to differ by less than a few percent for all observables, while the s95p-v1 equation of state generates spectra and flow coefficients which differ by ~10-20%. Calculations in which the HISQ/tree equation of state is sampled from the published error distribution are also observed to differ by less than a few percent.

   ↳ nucl-thhep-latnucl-exPRC(2016)·59 citations
5. 05*

   The PROSPECT Physics Program

   J. Ashenfelter · B. Balantekin · H. R. Band · G. Barclay · C. D. Bass · D. Berish · N. S. Bowden · A. Bowes · C. D. Bryan · J. P. Brodsky · J. J. Cherwinka · R. Chu and 52 other authors

   The Precision Reactor Oscillation and Spectrum Experiment, PROSPECT, is designed to make a precise measurement of the antineutrino spectrum from a highly-enriched uranium reactor and probe eV-scale sterile neutrinos by searching for neutrino oscillations over meter-long distances. PROSPECT is conceived as a 2-phase experiment utilizing segmented ${}^6$Li-doped liquid scintillator detectors for both efficient detection of reactor antineutrinos through the inverse beta decay reaction and excellent background discrimination. PROSPECT Phase I consists of a movable 3-ton antineutrino detector at distances of 7 - 12 m from the reactor core. It will probe the best-fit point of the ${\nu }_e$ disappearance experiments at 4$\sigma$ in 1 year and the favored region of the sterile neutrino parameter space at $>$3$\sigma$ in 3 years. With a second antineutrino detector at 15 - 19 m from the reactor, Phase II of PROSPECT can probe the entire allowed parameter space below 10 eV${}^2$ at 5$\sigma$ in 3 additional years. The measurement of the reactor antineutrino spectrum and the search for short-baseline oscillations with PROSPECT will test the origin of the spectral deviations observed in recent ${\theta }_{13}$ experiments, search for sterile neutrinos, and conclusively address the hypothesis of sterile neutrinos as an explanation of the reactor anomaly.

   ↳ physics.ins-dethep-exnucl-exJ.Phys.G(2016)·113 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.