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arXiv · 0902.1689

Exclusive production of rho^0 rho^0 pairs in gamma-gamma collisions at RHIC

M. Kłusek·W. Schäfer·A. Szczurek
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Abstract

We discuss exclusive electromagnetic production of two neutral $ρ$ mesons in coherent photon-photon processes in ultrarelativistic heavy-ion collisions. The cross section is calculated in the equivalent photon approximation (EPA). Both uncertainties of the flux factors and photon-photon cross sections are discussed in details. We show that inclusion of precise charge densities in nuclei is essential for realistic evaluations of the nuclear photon-photon cross sections. We find that the cross section, especially with realistic flux factors, is sensitive to low energy in the subsystem $γγ\to ρ^0 ρ^0$. The experimental data for the $γγ\to ρ^0 ρ^0$ cross section extracted from $e^+ e^-$ collisions are parametrized and used to estimate the nucleus-nucleus cross section. In addition, we include vector-dominance-model(VDM)--Regge contribution which becomes important at large photon-photon energy. Large nuclear cross sections are obtained. We discuss a possibility of focusing on the large-energy component. We find that both $ρ^0$ mesons are produced predominantly at midrapidities and could be measured by the STAR collaboration at RHIC.

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M. Kłusek, W. Schäfer, A. Szczurek. 2009-02-11. Exclusive production of rho^0 rho^0 pairs in gamma-gamma collisions at RHIC. https://doi.org/10.1016/j.physletb.2009.03.006

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