4,528 research outputs found

    Anisotropic flow of identified particles in Au+Au collisions at AGS energy

    Full text link
    Anisotropic flow of protons, π±\pi^{\pm}, K+K^+, deuterons, tritons, 3^3He, and 4^4He is analyzed as a function of transverse momentum for different centralities of the collision.Comment: RevTex, 4 pages, 4 figures included as eps files. To be published in the Proceedings of QM97, Tsukuba, Japa

    Bottomonium dipion transitions

    Full text link
    Dipion transitions of the subthreshold bottomonium levels Υ(nS)→Υ(n′S)ππ\Upsilon (nS)\to \Upsilon (n'S) \pi\pi with n>n′,n=2,3,4,n′=1,2n>n', n=2,3,4, n'=1,2 are studied in the framework of the chiral decay Lagrangian, derived earlier. The channels BBˉ,BBˉ∗+c.c,B∗Bˉ∗B\bar B, B\bar B^*+ c.c, B^* \bar B^* are considered in the intermediate state and realistic wave functions of Υ(nS),B\Upsilon (n S),B and B∗B^* are used in the overlap matrix elements. Imposing the Adler zero requirement on the transition matrix element, one obtains 2d and 1d dipion spectra in reasonable agreement with experiment.Comment: 34 pages, 18 figure

    Vorticity and particle polarization in heavy ion collisions (experimental perspective)

    Full text link
    The recent measurements of the global polarization and vector meson spin alignment along the system orbital momentum in heavy ion collisions are briefly reviewed. A possible connection between the global polarization and the chiral anomalous effects is discussed along with possible experimental checks. Future directions, in particular those aimed on the detailed mapping of the vorticity fields, are outlined. The Blast Wave model is used for an estimate of the anisotropic flow effect on the vorticity component along the beam direction. We also point to a possibility of a circular pattern in the vorticity field in asymmetric, e.g. Cu+Au, central collisions.Comment: 8 pages, Proceedings of the invited talk at Strangeness in Quark Matter 2017 Conference, Utrecht, Netherlands, July 201

    Semiclassical Calculation of Photon-Stimulated Schwinger Pair Creation

    Full text link
    We consider the electron-positron pair creation by a photon in an external constant electric field. The presented treatment is based on a purely quasiclassical calculation of the imaginary part of the on-shell photon polarization operator. By using this approach we find the pair production rate for photons with polarization parallel as well as orthogonal to the external electric field in the leading order in the parameter eE/m2eE / m ^ 2, which has been recently found by other methods. For the orthogonal polarization we also find a new contribution to the rate, which is leading in the ratio of the photon energy to the electron mass ω/m\omega/m. We also reproduce by a purely geometrical calculation the exponential factor in the probability of the stimulated pair creation at arbitrary energy of the photon.Comment: 16 pages, 4 figure

    Parity violation in hot QCD: how to detect it

    Full text link
    In a recent paper (arXive:hep-ph/0406125) entitled {\em Parity violation in hot QCD: why it can happen, and how to look for it}, D. Kharzeev argues for the possibility of P- and/or CP- violation effects in heavy-ion collisions, the effects that can manifest themselves via asymmetry in π±\pi^{\pm} production with respect to the direction of the system angular momentum. Here we present an experimental observable that can be used to detect and measure the effects.Comment: 2 pages, no figure

    Results on flow from the ALICE Collaboration

    Get PDF
    This short overview includes recent results from the ALICE Collaboration on anisotropic flow of charged and identified particles in sqrt(sNN) = 2.76 TeV Pb-Pb collisions. We also discuss charge dependent and event plane dependent azimuthal correlations that are important in tests of the chiral magnetic effect, as well as understanding the dynamics of the system evolution and hadronization process. Lastly, we present ALICE results obtained with a new technique, the event shape engineering, which allows to perform a physical analysis on events with very large or small flow.Comment: 8 pages, to be published in Proceedings of the Quark Matter 2012 Conference, Washington D.C., August 201
    • …
    corecore