Thu·May 25, 2017Thursday·May 25, 2017

1. 01*

   Photon structure studied at an Electron Ion Collider

   Xiaoxuan Chu🇨🇳 · Elke-Caroline Aschenauer🇺🇸 · Jeong-Hun Lee🇺🇸 · Liang Zheng🇨🇳

   A future Electron Ion Collider (EIC) will be able to provide collisions of polarized electrons with protons and heavy ions over a wide range of center-of-mass energies (20 $\mathrm{GeV}$ to 140 $\mathrm{GeV}$) at an instanteous luminosity of $10^{33}-10^{34}$ cm${}^{-2}$s${}^{-1}$. One of its promising physics programs is the study of the partonic structure of quasi-real photons. Measuring di-jets in quasi-real photoproduction events, one can effectively access the underlying parton dynamics of the photons. In this paper, we discuss the feasibility of tagging resolved photon processes and measuring the di-jet cross section as a function of jet transverse momentum in the range of $0.01<x_{\gamma }^{rec}<1$ at an EIC. It will be shown that both unpolarized and polarized parton distributions in the photon can be extracted, and that the flavor of the parton can be tagged at an EIC.

   nucl-exPRD(2017)·27 citations
2. 02*

   Absence of jet quenching in peripheral nucleus-nucleus collisions

   Constantin Loizides (LBNL)🇺🇸 · Andreas Morsch (CERN)🇨🇭

   Medium effects on the production of high-$p_{\mathrm{T}}$ particles in nucleus-nucleus (AA) collisions are generally quantified by the nuclear modification factor ($R_{\mathrm{AA}}$), defined to be unity in absence of nuclear effects. Modeling particle production including a nucleon-nucleon impact parameter dependence, we demonstrate that $R_{\mathrm{AA}}$ at midrapidity in peripheral AA collisions can be significantly affected by event selection and geometry biases. Even without jet quenching and shadowing, these biases cause an apparent suppression for $R_{\mathrm{AA}}$ in peripheral collisions, and are relevant for all types of hard probes and all collision energies. Our studies indicate that calculations of jet quenching in peripheral AA collisions should account for the biases, or else they will overestimate the relevance of parton energy loss. Similarly, expectations of parton energy loss in light-heavy collision systems based on comparison with apparent suppression seen in peripheral $R_{\mathrm{AA}}$ should be revised. Our interpretation of the peripheral $R_{\mathrm{AA}}$ data would unify observations for lighter collision systems or lower energies where significant values of elliptic flow are observed despite the absence of strong jet quenching.

   nucl-exnucl-thPLB(2017)·105 citations
3. 03*

   Photon and Pomeron -- induced production of Dijets in $pp$, $pA$ and $AA$ collisions

   E. Basso🇧🇷 · V. P. Goncalves🇧🇷 · A. K. Kohara🇧🇷 · M. S. Rangel🇧🇷

   In this paper we present a detailed comparison of the dijet production by photon -- photon, photon -- pomeron and pomeron -- pomeron interactions in $pp$, $pA$ and $\mathrm{AA}$ collisions at the LHC energy. The transverse momentum, pseudo -- rapidity and angular dependencies of the cross sections are calculated at LHC energy using the Forward Physics Monte Carlo (FPMC), which allows to obtain realistic predictions for the dijet production with two leading intact hadrons. We obtain that $\gamma \text{pom}$ channel is dominant at forward rapidities in $pp$ collisions and in the full kinematical range in the nuclear collisions of heavy nuclei. Our results indicate that the analysis of dijet production at the LHC can be useful to test the Resolved Pomeron model as well as to constrain the magnitude of the absorption effects.

   ↳ hep-phhep-exnucl-exnucl-thEPJC(2017)·20 citations
4. 04*

   Search for neutrinoless quadruple-$\beta$ decay of ${}^{150}$Nd with the NEMO-3 detector

   R. Arnold🇫🇷 · C. Augier🇫🇷 · A. S. Barabash🇷🇺 · A. Basharina-Freshville🇬🇧 · S. Blondel🇫🇷 · S. Blot🇬🇧 · M. Bongrand🇫🇷 · D. Boursette🇫🇷 · V. Brudanin🇷🇺 · J. Busto🇫🇷 · A.J. Caffrey🇺🇸 · S. Calvez🇫🇷 and 87 other authors

   We report the results of a first experimental search for lepton number violation by four units in the neutrinoless quadruple-$\beta$ decay of ${}^{150}$Nd using a total exposure of $0.19$ kg$\cdot$y recorded with the NEMO-3 detector at the Modane Underground Laboratory (LSM). We find no evidence of this decay and set lower limits on the half-life in the range $T_{1/2}>(1.1-3.2)\times 10^{21}$ y at the $90\%$ CL, depending on the model used for the kinematic distributions of the emitted electrons.

   ↳ hep-exnucl-exPRL(2017)·39 citations
5. 05*

   The impact of neutral impurity concentration on charge drift mobility in n-type germanium

   H. Mei🇯🇵 · G.-J. Wang🇺🇸 · G. Yang🇺🇸 · D.-M. Mei🇺🇸

   The impact of neutral impurity scattering of electrons on the charge drift mobility in high purity n-type germanium crystals at 77 Kelvin is investigated. We calculated the contributions from ionized impurity scattering, lattice scattering, and neutral impurity scattering to the total charge drift mobility using theoretical models. The experimental data such as charge carrier concentration, mobility and resistivity are measured by Hall Effect system at 77 Kelvin. The neutral impurity concentration is derived from the Matthiessen's rule using the measured Hall mobility and ionized impurity concentration. The radial distribution of the neutral impurity concentration in the self-grown crystals is determined. Consequently, we demonstrated that neutral impurity scattering is a significant contribution to the charge drift mobility, which has a dependence on the concentration of neutral impurities in high purity n-type germanium crystal.

   ↳ physics.ins-detnucl-exJINST(2017)·7 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.