43 research outputs found
Exclusive meson pair production in peripheral ultrarelativistic heavy ion collisions
The cross sections for exclusive and meson pair
production in peripheral nucleus - nucleus collisions are calculated and
several differential distributions are presented. The calculation of the
elementary cross section is done within the
heavy-quark approximation and in the Brodsky- Lapage formalism with
distribution amplitudes describing recent CLEO data on leptonic decay.
Realistic (Fourier transform of charge density) charge form factors of nuclei
are used to generate photon flux factors. Absorption effects are discussed and
quantified. The cross sections of a few nb are predicted for RHIC and of a few
hundreds of nb for LHC with details depending on the approximation made in
calculating elementary cross sections.Comment: 11 pages, 8 figure
Exclusive production of lepton, quark and meson pairs in peripheral ultrarelativistic heavy ion collisions
We discuss exclusive production of lepton-antilepton, quark-antiquark, and pairs in ultraperipheral, ultrarelativistic heavy-ion
collisions.
The cross sections for exclusive production of pairs of particles is
calculated in Equivalent Photon Approximation (EPA). Realistic (Fourier
transform of charge density) charge form factors of nuclei are used and the
corresponding results are compared with the cross sections calculated with
monopole form factor used in the literature. Absorption effects are discussed
and quantified. The cross sections obtained with realistic form factors are
significantly smaller than those obtained with the monopole form factors.Comment: 9 pages, 13 figures an invited talk at the international conference
"Hadron Structure 2011", Slovakia, June 201
Electromagnetic interaction of low transverse momentum electrons and positrons with heavy nuclei in ultra-peripheral ultra-relativistic heavy-ion collisions
The photon-photon interaction in ultra-relativistic heavy-ion collision is a
source of the pairs. The photon-photon fusion leads the lepton
creation in the broad configuration space around "collision" point. Those
created close to heavy nuclei may undergo strong interaction with them. The
impact parameter space distribution of electrons and positrons are calculated
within the b-space EPA model of such collisions. The evolution due to the
electromagnetic interaction of with nuclei is studied, and the
distortion of rapidity and transverse momentum distributions are shown. We show
first exploratory results for the reaction Pb+Pb at 17.3 GeV
(SPS) and 200 GeV (RHIC) energies. We provide results for selected creation
points and when integrating over their position as dictated by the -space
EPA model. We observe strong effects at low transverse momenta, so far not
measured regions of the phase space. In particular, we predict a possible
sizeable accumulation of electrons with rapidities close to the beam rapidity.
The EM effects lead to asymmetry in the production of electrons and positrons.Comment: 30 pages, 20 figure
Exclusive Four-pion Photoproduction in Ultra-peripheral Heavy-ion Collisions at RHIC and LHC Energies
We study the photoproduction of exclusive 2π+2π− mesons in ultra-peripheral heavy-ion collisions at the RHIC and LHC energies. Predictions in photon–nucleus interactions are calculated for various resonances at central and forward rapidities. The recent H1 preliminary data are utilized to improve the description of the poorly known γp→4π±p process. We present the comparisons of our results to the available STAR data at RHIC, and made predictions for the LHC energies