Mon·Dec 25, 2017Monday·December 25, 2017

1. 01*

   Nucleon shadowing effects in $Cu+Cu$ and $Au+Au$ collisions at RHIC within the HIJING code

   Khaled Abdel-Waged🇸🇦 · Nuha Felemban🇸🇦

   The centrality dependence of pseudorapidity density of charged particles ($d{N}_{ch}/d\eta$) in $Cu+Cu$ ($Au+Au$) collisions at RHIC energy of $\sqrt{s_{{}_{\mathrm{NN}}}}=22.4$ , $62.4$ and $200$ ($19.6$, $62.4$ and $200$) GeV, is investigated within an improved HIJING code. The standard HIJING model is enhanced by a prescription for collective nucleon-nucleon ($NN$) interactions and more modern parton distribution functions. The collective $NN$-interactions are used to induce both cascade and nucleon shadowing effects. We find collective cascade broadens the pseudorapidity distributions in the tails (at $|\eta |>y_{\mathrm{beam}}$) above $25-30\%$ collision centrality to be consistent with the $d{N}_{ch}/d\eta$ data at $\sqrt{s_{{}_{\mathrm{NN}}}}=19.6$, $22.4$, $62.4$ GeV. The overall contribution of nucleon shadowing is shown to depress the whole shape of $d{N}_{ch}/d\eta$ in the primary interaction region (at $|\eta |<y_{\mathrm{beam}}$) for semiperipheral ($20-25$ \%) and peripheral ($\ge 35-40$\%) $Cu+Cu$ ($Au+Au$) interactions at $\sqrt{s_{{}_{\mathrm{NN}}}}=200$ GeV, in accordance with the PHOBOS data.

   ↳ hep-phnucl-exnucl-thJ.Phys.G(2018)·3 citations
2. 02*

   A Dual-phase Xenon TPC for Scintillation and Ionisation Yield Measurements in Liquid Xenon

   Laura Baudis🇨🇭 · Yanina Biondi🇨🇭 · Chiara Capelli🇨🇭 · Michelle Galloway🇨🇭 · Shingo Kazama🇨🇭 · Alexander Kish🇨🇭 · Payam Pakarha🇨🇭 · Francesco Piastra🇨🇭 · Julien Wulf🇨🇭

   A small-scale, two-phase (liquid/gas) xenon time projection chamber (Xurich II) was designed, constructed and is under operation at the University of Zurich. Its main purpose is to investigate the microphysics of particle interactions in liquid xenon at energies below 50 keV, which are relevant for rare event searches using xenon as target material. Here we describe in detail the detector, its associated infrastructure, and the signal identification algorithm developed for processing and analysing the data. We present the first characterisation of the new instrument with calibration data from an internal 83m-Kr source. The zero-field light yield is 15.0 and 14.0 photoelectrons/keV at 9.4 keV and 32.1 keV, respectively, and the corresponding values at an electron drift field of 1 kV/cm are 10.8 and 7.9 photoelectrons/keV. The charge yields at these energies are 28 and 31 electrons/keV, with the proportional scintillation yield of 24 photoelectrons per one electron extracted into the gas phase, and an electron lifetime of 200 $\mu$s. The relative energy resolution, $\sigma /E$, is 11.9 % and 5.8 % at 9.4 keV and 32.1 keV, respectively using a linear combination of the scintillation and ionisation signals. We conclude with measurements of the electron drift velocity at various electric fields, and compare these to literature values.

   ↳ astro-ph.IMhep-exnucl-exphysics.ins-detEPJC(2018)·17 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.