Mon·Aug 11, 2014Monday·August 11, 2014

1. 01*

   Study of the $\vec{p}d\to n\{pp{\}}_s$ charge-exchange reaction using a polarised deuterium target

   B. Gou · D. Mchedlishvili · Z. Bagdasarian · S. Barsov · D. Chiladze · S. Dymov · R. Engels · M. Gaisser · R. Gebel · K. Grigoryev · M. Hartmann · A. Kacharava and 29 other authors

   The vector and tensor analysing powers, $A_y$ and $A_{yy}$, of the $\vec{p}d\to n\{pp{\}}_s$ charge-exchange reaction have been measured at a beam energy of 600 MeV at the COSY-ANKE facility by using an unpolarised proton beam incident on an internal storage cell target filled with polarised deuterium gas. The low energy recoiling protons were measured in a pair of silicon tracking telescopes placed on either side of the target. Putting a cut of 3 MeV on the diproton excitation energy ensured that the two protons were dominantly in the ${}^1{S}_0$ state, here denoted by $\{pp{\}}_s$. The polarisation of the deuterium gas was established through measurements in parallel of proton-deuteron elastic scattering. By analysing events where both protons entered the same telescope, the charge-exchange reaction was measured for momentum transfers $q\ge 160$ MeV/$c$. These data provide a good continuation of the earlier results at $q\le 140$ MeV/$c$ obtained with a polarised deuteron beam. They are also consistent with impulse approximation predictions with little sign evident for any modifications due to multiple scatterings.

   nucl-exnucl-thPLB(2015)·4 citations
2. 02*

   Improving Photoelectron Counting and Particle Identification in Scintillation Detectors with Bayesian Techniques

   M. Akashi-Ronquest🇺🇸 · P.-A. Amaudruz🇨🇦 · M. Batygov🇨🇦 · B. Beltran🇨🇦 · M. Bodmer🇺🇸 · M.G. Boulay🇨🇦 · B. Broerman🇨🇦 · B. Buck🇺🇸 · A. Butcher🇬🇧 · B. Cai🇨🇦 · T. Caldwell🇺🇸 · M. Chen🇨🇦 and 70 other authors

   Many current and future dark matter and neutrino detectors are designed to measure scintillation light with a large array of photomultiplier tubes (PMTs). The energy resolution and particle identification capabilities of these detectors depend in part on the ability to accurately identify individual photoelectrons in PMT waveforms despite large variability in pulse amplitudes and pulse pileup. We describe a Bayesian technique that can identify the times of individual photoelectrons in a sampled PMT waveform without deconvolution, even when pileup is present. To demonstrate the technique, we apply it to the general problem of particle identification in single-phase liquid argon dark matter detectors. Using the output of the Bayesian photoelectron counting algorithm described in this paper, we construct several test statistics for rejection of backgrounds for dark matter searches in argon. Compared to simpler methods based on either observed charge or peak finding, the photoelectron counting technique improves both energy resolution and particle identification of low energy events in calibration data from the DEAP-1 detector and simulation of the larger MiniCLEAN dark matter detector.

   ↳ physics.ins-detastro-ph.IMhep-exnucl-exAstropart.Phys.(2015)·31 citations
3. 03*

   Measurements of the heavy-flavour nuclear modification factor in p--Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV with ALICE at the LHC

   Shuang Li (for the ALICE Collaboration)🇨🇳

   The heavy-flavour nuclear modification factor $R_{\mathrm{pPb}}$ has been measured with the ALICE detector in p--Pb collisions at the nucleon--nucleon center of mass energy $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV at the CERN LHC in a wide rapidity and transverse momentum range, as well as in several decay channels. $R_{\mathrm{pPb}}$ is consistent with unity within uncertainties at mid-rapidity and forward rapidity. In the backward region a slight enhancement of the yield of heavy-flavour decay muons is found in the region $2<p_{\mathrm{T}}<4$ GeV/$c$. The results are described within uncertainties by theoretical calculations that include initial-state effects. The measurements add experimental evidence that the suppression of heavy-flavour production observed at high $p_{\mathrm{T}}$ in central Pb--Pb collisions with respect to pp collisions is due to a medium effect induced by the interaction of heavy quarks with the partonic matter.

   ↳ hep-exnucl-exNPA(2014)·25 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.