Mon·Jul 18, 2011Monday·July 18, 2011

1. 01*

   Overview of experimental results in PbPb collisions at sqrt{s_NN} = 2.76 TeV by the CMS Collaboration

   Bolek Wyslouch (for the CMS collaboration)🇫🇷

   The CMS experiment at the LHC is a general-purpose apparatus with a set of large acceptance and high granularity detectors for hadrons, electrons, photons and muons, providing unique capabilities for both proton-proton and ion-ion collisions. The data collected during the November 2010 PbPb run at sqrt{s_NN} = 2.76 TeV was analyzed and multiple measurements of the properties of the hot and dense matter were obtained. Global event properties, detailed study of jet production and jet properties, isolated photons, quarkonia and weak bosons were measured and compared to pp data and Monte Carlo simulations.

   nucl-exJ.Phys.G(2011)·26 citations
2. 02*

   Measurement of the ${\nu }_e$ and Total ${}^8$B Solar Neutrino Fluxes with the Sudbury Neutrino Observatory Phase-III Data Set

   B. Aharmim🇨🇦 · S.N. Ahmed🇨🇦 · J.F. Amsbaugh🇺🇸 · J.M. Anaya🇺🇸 · A.E. Anthony🇺🇸 · J. Banar🇺🇸 · N. Barros🇩🇪 · E.W. Beier🇺🇸 · A. Bellerive🇨🇦 · B. Beltran🇨🇦 · M. Bergevin🇺🇸 · S.D. Biller🇬🇧 and 138 other authors

   This paper details the solar neutrino analysis of the 385.17-day Phase-III data set acquired by the Sudbury Neutrino Observatory (SNO). An array of ${}^3$He proportional counters was installed in the heavy-water target to measure precisely the rate of neutrino-deuteron neutral-current interactions. This technique to determine the total active ${}^8$B solar neutrino flux was largely independent of the methods employed in previous phases. The total flux of active neutrinos was measured to be $5.54_{-0.31}^{+0.33}(stat.{)}_{-0.34}^{+0.36}(syst.)\times 10^6$ cm${}^{-2}$ s${}^{-1}$, consistent with previous measurements and standard solar models. A global analysis of solar and reactor neutrino mixing parameters yielded the best-fit values of $\Delta m^2=7.59_{-0.21}^{+0.19}\times 10^{-5}{eV}^2$ and $\theta =34.4_{-1.2}^{+1.3}$ degrees.

   nucl-exastro-ph.SRhep-exPRC(2013)·97 citations
3. 03*

   Strangeness Enhancement in Cu+Cu and Au+Au Collisions at \sqrt{s_{NN}} = 200 GeV

   STAR Collaboration: H. Agakishiev · M. M. Aggarwal · Z. Ahammed · A. V. Alakhverdyants · I. Alekseev · J. Alford · B. D. Anderson · C. D. Anson · D. Arkhipkin · G. S. Averichev · J. Balewski · L. S. Barnby and 360 other authors

   We report new STAR measurements of mid-rapidity yields for the $\Lambda$, $\bar{\Lambda }$, $K_S^0$, ${\Xi }^{-}$, ${\bar{\Xi }}^{+}$, ${\Omega }^{-}$, ${\bar{\Omega }}^{+}$ particles in Cu+Cu collisions at \sNN{200}, and mid-rapidity yields for the $\Lambda$, $\bar{\Lambda }$, $K_S^0$ particles in Au+Au at \sNN{200}. We show that at a given number of participating nucleons, the production of strange hadrons is higher in Cu+Cu collisions than in Au+Au collisions at the same center-of-mass energy. We find that aspects of the enhancement factors for all particles can be described by a parameterization based on the fraction of participants that undergo multiple collisions.

   nucl-exPRL(2012)·187 citations
4. 04*

   Jet measurements by the CMS experiment in pp and PbPb collisions

   Christof Roland (for the CMS Collaboration)🇺🇸

   The energy loss of fast partons traversing the strongly interacting matter produced in high-energy nuclear collisions is one of the most interesting observables to probe the nature of the produced medium. The multipurpose Compact Muon Solenoid (CMS) detector is well designed to measure these hard scattering processes with its high resolution calorimeters and high precision silicon tracker. Analyzing data from pp and PbPb collisions at a center-of-mass energy of 2.76 TeV parton energy loss is observed as a significant imbalance of dijet transverse momentum. To gain further understanding of the parton energy loss mechanism the redistribution of the quenched jet energy was studied using the transverse momentum balance of charged tracks projected onto the direction of the leading jet. In contrast to pp collisions, a large fraction the momentum balance for asymmetric jets is found to be carried by low momentum particles at large angular distance to the jet axis. Further, the fragmentation functions for leading and subleading jets were reconstructed and were found to be unmodified compared to measurements in pp collisions. The results yield a detailed picture of parton propagation in the hot QCD medium.

   nucl-exJ.Phys.G(2011)·10 citations
5. 05*

   On timelike Compton scattering at medium and high energies

   B. Pire🇫🇷 · L. Szymanowski🇵🇱 · J. Wagner🇵🇱

   We emphasize the complementarity of timelike and spacelike studies of deep exclusive processes, taking as an example the case of timelike Compton Scattering (TCS) i.e. the exclusive photoproduction of a lepton pair with large invariant mass, vs deeply virtual Compton scattering (DVCS) i.e. the exclusive leptoproduction of a real photon. Both amplitudes factorize with the same generalized parton distributions (GPDs) as their soft parts and coefficient functions which differ significantly at next to leading order in alpha_s. We also stress that data on TCS at very high energy should be available soon thanks to the study of ultraperipheral collisions at the LHC, opening a window on quark and gluon GPDs at very small skewness.

   ↳ hep-phhep-exnucl-exnucl-thFew Body Syst.(2012)·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.