Mon·Nov 23, 2015Monday·November 23, 2015

1. 01*

   Forward rapidity $\psi (2S)$ meson production in pp, p-Pb and Pb-Pb collisions with ALICE at the LHC

   Marco Leoncino (for the ALICE Collaboration)🇮🇹

   The ALICE Collaboration has studied the inclusive $\psi (2S)$ meson production in pp, p-Pb and Pb-Pb collisions at the CERN LHC. The $\psi (2S)$ is detected through its decay to a muon pair, using the forward Muon Spectrometer, which covers the pseudo-rapidity range $-4<\eta <-2.5$. The $\psi (2S)$ production cross sections in pp collisions are presented as a function of rapidity (y) and transverse momentum ($p_{\mathrm{T}}$). In p-Pb collisions, $\psi (2S)$ results are compared to the J/$\psi$ ones by the ratio of their production cross sections as a function of rapidity, transverse momentum and event activity. The $\psi (2S)$ nuclear modification factor, $R_{\mathrm{pA}}$, is also discussed. The results show a $\psi (2S)$ suppression compared to the one observed for the J/$\psi$ meson and are not described by theoretical models including cold nuclear matter effects as nuclear shadowing and energy loss. Finally, the preliminary results of $\psi (2S)$ meson production in Pb-Pb collisions are shown in two $p_{\mathrm{T}}$ ranges as a function of the collision centrality.

   nucl-exJ.Phys.Conf.Ser.(2015)·1 citation
2. 02*

   Measurement of W-boson production in p-Pb collisions at the LHC with ALICE

   Kgotlaesele Johnson Senosi (for the ALICE collaboration)🇿🇦

   ALICE (A Large Ion Collider Experiment) is designed and optimized to study ultra-relativistic heavy-ion collisions, in which a hot and dense strongly-interacting medium is created. W bosons are produced in hard scattering processes occurring at the early stage of the collision and, since they are not affected by the strong interaction, they can be used as a benchmark for medium-induced effects. In proton-nucleus collisions the production of W bosons can be used to study the modification of parton distribution functions in the nucleus and to test the validity of binary collision scaling. The latter is studied by measuring the yield of W bosons in different intervals of event activity. In ALICE, the production of W bosons is measured via the contribution of their muonic decays to the inclusive $p_{\mathrm{T}}$-differential muon yield reconstructed with the muon spectro-meter at forward ($2.03<y_{cms}^{\mu }<3.53$) and backward rapidity ($-4.46<y_{cms}^{\mu }<-2.96$). The recent results from p--Pb collisions at a centre-of-mass energy of $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV are presented and the measured cross sections are compared to perturbative Quantum Chromodynamics calculations at next-to-leading order.

   ↳ hep-exnucl-exPoS(2015)·9 citations
3. 03*

   Phonon contributions to ab initio double mass differences of magic nuclei

   E. E. Saperstein🇷🇺 · M. Baldo🇮🇹 · N. V. Gnezdilov · S. V. Tolokonnikov🇷🇺

   Odd-even double mass differences (DMD) of magic nuclei are found within the approach starting from the free $NN$ interaction with account for particle-phonon coupling (PC) effects. We consider three PC effects: the phonon induced effective interaction, the renormalization of the "ends" due to the $Z$-factor corresponding to the pole PC contribution to the nucleon mass operator and the change of the single-particle energies. The perturbation theory in $g_L^2$, where $g_L$ is the vertex of the $L$-phonon creation, is used for PC calculations. PC corrections to single-particle energies are found self-consistently with an approximate account for the tadpole diagram. Results for magic ${}^{40,48}$Ca, ${}^{56,78}$Ni, ${}^{100,132}$Sn and ${}^{208}$Pb nuclei are presented. For lighter part of this set of nuclei, from ${}^{40}$Ca till ${}^{56}$Ni, the cases divide approximately in half between those where the PC corrections to DMD values make agreement with the data better and the ones with the opposite result. In the major part of the cases of worsening of description of DMD, a poor applicability of the perturbation theory for the induced interaction is the most probable reason of the phenomenon. For intermediate nuclei, ${}^{78}$Ni and ${}^{100}$Sn, there is no sufficiently accurate data on masses of nuclei necessary for finding DMD values. Finally, for heavier nuclei, ${}^{132}$Sn and ${}^{208}$Pb, PC corrections always make agreement with the experiment better.

   ↳ nucl-thnucl-exPRC(2016)·9 citations
4. 04*

   Meson assisted dibaryons

   Avraham Gal🇮🇱

   We discuss a new type of L=0 positive-parity dibaryons, pion-B-B', where the dominant binding mechanism is provided by resonating p-wave pion-baryon interactions. Recent calculations of such pion assisted dibaryons are reviewed with special emphasis placed on the non-strange I(JP)=1(2+) N-Delta dibaryon D_{12}(2150) studied recently at JLab, and on the 0(3+) Delta-Delta dibaryon D_{03}(2380) discovered recently by the WASA-at-COSY Collaboration. We review recent searches by the HADES Collaboration at GSI and by the E15 and E27 Experiments at J-PARC for a strangeness S=-1 I(JP)=1/2(0-) K-pp dibaryon and perhaps also for a strange I(JP)=3/2(2+) N-Sigma(1385) pion assisted dibaryon Y_{3/2(2+)}(2270). Charm C=+1 dibaryons, predicted with these same I(JP) values, are also briefly reviewed.

   ↳ nucl-thhep-phnucl-exActa Phys.Polon.B(2016)·35 citations
5. 05*

   Sieving hydrogen isotopes through two dimensional crystals

   M. Lozada-Hidalgo · S. Hu🇨🇳 · O. Marshall · A. Mishchenko · A. N. Grigorenko · R. A. W. Dryfe · B. Radha · I. V. Grigorieva · A. K. Geim

   One-atom-thick crystals are impermeable to atoms and molecules, but hydrogen ions (thermal protons) penetrate through them. We show that monolayers of graphene and boron nitride can be used to separate hydrogen ion isotopes. Employing electrical measurements and mass spectrometry, we find that deuterons permeate through these crystals much slower than protons, resulting in a separation factor of ~10 at room temperature. The isotope effect is attributed to a difference of about 60 meV between zero-point energies of incident protons and deuterons, which translates into the equivalent difference in the activation barriers posed by two dimensional crystals. In addition to providing insight into the proton transport mechanism, the demonstrated approach offers a competitive and scalable way for hydrogen isotope enrichment.

   ↳ cond-mat.mtrl-scicond-mat.mes-hallnucl-exScience(2016)·2 citations
6. 06*

   Hall A Annual Report 2014

   M.M. Dalton🇺🇸 · E. Chudakov🇺🇸 · J. Gomez🇺🇸 · D. W. Higinbotham🇺🇸 · C. Keppel🇺🇸 · R. Michaels🇺🇸 · L. Myers🇺🇸 · K. Aniol🇺🇸 · S. Iqbal🇺🇸 · N. See🇺🇸 · J.R. Arrington🇺🇸 · M.V. Ivanov🇧🇬 and 11 other authors

   Report of the experimental activities in Hall A at Thomas Jefferson National Accelerator Facility during 2013.

   ↳ physics.ins-detnucl-ex0 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.