Mon·Dec 1, 2014Monday·December 1, 2014

1. 01*

   How much does the hadronic phase contribute to the observed anisotropic flow at the LHC?

   Raimond Snellings🇳🇱

   Elliptic flow signals the presence of multiple interactions between the constituents of the created matter in heavy-ion collisions. This includes possible contributions from the different phases, including the hadronic phase. In these proceedings I will first show that the energy dependence of elliptic flow, based on recent ALICE and STAR beam energy scan measurements, can largely be understood in terms of a boosted thermal system. In addition, a detailed comparison between the identified particle elliptic flow measured by the ALICE collaboration and viscous hydrodynamical model calculations with and without a hadronic afterburner is performed to constrain the possible effects of individual hadron-hadron re-interaction cross-sections.

   nucl-exEPJ Web Conf.(2015)·11 citations
2. 02*

   Observation of the critical end point in the phase diagram for hot and dense nuclear matter

   Roy A. Lacey (Depts. of Chemistry and Physics, Stony Brook University)🇺🇸

   Excitation functions for the Gaussian emission source radii difference ($R_{\text{out}}^2-R_{\text{side}}^2$) obtained from two-pion interferometry measurements in Au+Au ($\sqrt{s_{NN}}=7.7-200$ GeV) and Pb+Pb ($\sqrt{s_{NN}}=2.76$ TeV) collisions, are studied for a broad range of collision centralities. The observed non-monotonic excitation functions validate the finite-size scaling patterns expected for the deconfinement phase transition and the critical end point (CEP), in the temperature vs. baryon chemical potential ($T,{\mu }_B$) plane of the nuclear matter phase diagram. A Finite-Size Scaling (FSS) analysis of these data indicate a second order phase transition with the estimates $T^{\text{cep}}\sim 165$~MeV and ${\mu }_B^{\text{cep}}\sim 95$~MeV for the location of the critical end point. The critical exponents ($\nu \sim 0.66$ and $\gamma \sim 1.2$) extracted via the same FSS analysis, places the CEP in the 3D Ising model universality class.

   nucl-exnucl-thPRL(2015)·120 citations
3. 03*

   A New Hadron Spectroscopy

   Stephen Lars Olsen🇰🇷

   QCD-motivated models for hadrons predict an assortment of "exotic" hadrons that have structures that are more complex than the quark-antiquark mesons and three-quark baryons of the original quark-parton model. These include pentaquark baryons, the six-quark H-dibaryon, and tetraquark, hybrid and glueball mesons. Despite extensive experimental searches, no unambiguous candidates for any of these exotic configurations have been identified. On the other hand, a number of meson states, one that seems to be a proton-antiproton bound state, and others that contain either charmed-anticharmed quark pairs or bottom-antibottom quark pairs, have been recently discovered that neither fit into the quark-antiquark meson picture nor match the expected properties of the QCD-inspired exotics. Here I briefly review results from a recent search for the H-dibaryon, and discuss some properties of the newly discovered states --the proton-antiproton state and the so-called XYZ mesons-- and compare them with expectations for conventional quark-antiquark mesons and the predicted QCD-exotic states.

   ↳ hep-exhep-phnucl-exnucl-thFront.Phys.(Beijing)(2015)·112 citations
4. 04*

   Study of azimuthal correlations between D mesons and charged particles with the ALICE experiment

   Fabio Colamaria (for the ALICE Collaboration)🇮🇹

   A study of azimuthal correlations between D${}^0$, D${}^{+}$, and D${}^{\ast +}$ and charged particles in pp collisions at $\sqrt{s}$ = 7 TeV and p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV is presented. D mesons were reconstructed from their hadronic decays at central rapidity ($|y|<0.5$) in the transverse momentum range $3\le p_{\mathrm{T}}^{\mathrm{D}}\le 16$ GeV/$c$ and they were correlated with charged particles reconstructed in the pseudorapidity range $|\eta |<0.8$. Perspectives for the measurement in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.5 TeV after the ALICE upgrade are presented as well.

   ↳ hep-exnucl-exJ.Phys.Conf.Ser.(2015)·1 citation
5. 05*

   Multiparticle production in nuclear collisions using effective-energy approach

   Aditya Nath Mishra🇮🇳 · Raghunath Sahoo🇮🇳 · Edward K.G. Sarkisyan🇨🇭 · Alexander S. Sakharov🇨🇭

   The dependencies of charged particle pseudorapidity density and transverse energy pseudorapidity density at midrapidity on the collision energy and on the number of nucleon participants, or centrality, measured in nucleus-nucleus collisions are studied in the energy range spanning a few GeV to a few TeV per nucleon. The study is based on the earlier proposed model, combining the constituent quark picture together with Landau relativistic hydrodynamics and shown to interrelate the measurements from different types of collisions. Within this picture, the dependence on the number of participants in heavy-ion collisions are found to be well described in terms of the effective energy defined as a centrality-dependent fraction of the collision energy. The effective energy approach is shown to reveal a similarity in the energy dependence for the most central and centrality data in the entire available energy range. Predictions are made for the forthcoming higher-energy measurements in heavy-ion collisions at the LHC.

   ↳ hep-phhep-exnucl-exnucl-thEPJ Web Conf.(2015)·0 citations
6. 06*

   Constraints on the chiral unitary $\bar{K}N$ amplitude from $\pi \Sigma K^{+}$ photoproduction data

   Maxim Mai🇩🇪 · Ulf-G. Meißner🇩🇪

   A chiral unitary approach for antikaon-nucleon scattering in on-shell factorization is studied. We find multiple sets of parameters for which the model describes all existing hadronic data similarly well. We confirm the two-pole structure of the $\Lambda (1405)$. The narrow $\Lambda (1405)$ pole appears at comparable positions in the complex energy plane, whereas the location of the broad pole suffers from a large uncertainty. In the second step, we use a simple model for photoproduction of $K^{+}\pi \Sigma$ off the proton and confront it with the experimental data from the CLAS collaboration. It is found that only a few of the hadronic solutions allow for a consistent description of the CLAS data within the assumed reaction mechanism.

   ↳ hep-phhep-exnucl-exnucl-thEPJA(2015)·207 citations
7. 07*

   On theoretical uncertainty of color dipole phenomenology in the J/Psi and Upsilon photoproduction in pA and AA collisions at the CERN Large Hadron Collider

   G. Sampaio dos Santos🇧🇷 · M.V.T. Machado🇧🇷

   We investigate the theoretical uncertainty on the predictions for the photoproduction of J/psi and Upsilon states in the proton-nucleus and nucleus-nucleus collisions at the LHC within the color dipole formalism. Predictions for the rapidity distributions are presented and the dependence on the meson wavefunction, heavy quark mass as well as the models for the dipole cross section are analyzed. We compare directly the theoretical results to the recent data from ALICE collaboration on J/psi production in pPb collisions at a centre-of-mass energy per nucleon pair of 5.02 TeV and in PbPb collisions at a centre-of-mass energy per nucleon pair of 2.76 TeV. Predictions are also performed for ${\rm Y}$ state in PbPb and pPb and pp collisions at the LHC energies, including the coherent and incoherent contributions.

   ↳ hep-phhep-exnucl-exJ.Phys.G(2015)·55 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.