Measurement of exclusive p(+)p(-) production in mid-virtuality two-photon interactions and study of the yy* -> pp process at LEP
Physics Letters B 615,1-2 (2005) 19-30;
Exclusive p(+)p(-) production in two-photon collisions between a quasi-real photon, gamma, and a mid-virtuality photon, gamma*, is studied with data collected at LEP at centre-of-mass energies 183 GeV <= root s- <= 209 GeV with a total integrated luminosity of 684.8 pb(-1). The cross section of the gamma gamma* -> p(+)p(-) process is determined as a function of the photon virtuality, Q(2), and the two-photoncentre-of-mass energy, W-gamma gamma, in thekinernatic region: 0.2 GeV2 < Q(2) < 0.85 GeV2 and 1.1 GeV < W gamma gamma < 3 GeV. These results, together with previous L-3 measurements of p(0) p(0) and p(+) to p(-) production, allow a study of the gamma gamma* -> pp process over the Q(2)-region 0.2 GeV2 <= Q(2) <= 30 GeV2. (c) 2005 Published by Elsevier B.V.
gamma-gamma-collisions;; photon-photon collisions;; l3 experiment;; vector-dominance;; q2qbar2 mesons;; 4-quark states;; pi-pi;; detector;; threshold;; gamma-gamma->rho+rho
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