Production of D ∗ mesons in photon-photon collisions at √ see = 183 GeV and 189 GeV using the OPAL detector at LEP

Abstract

The inclusive production of D ∗± mesons in photon-photon collisions has been measured using the OPAL detector at LEP at e +e − centre-of-mass energies √ s ee of 183 and 189 GeV. The D ∗+ mesons are reconstructed in their decay to D 0 π + with the D 0 observed in the two decay modes K − π + and K − π + π − π +. After background subtraction, 121 ± 14 (stat.) D ∗± events have been selected. Jets are reconstructed using a cone jet finding algorithm to separate direct and single-resolved events. Differential cross-sections dσ/ dp T D ∗ and dσ/ dvbη D ∗ vb as functions of the D ∗± transverse momentum p T D ∗ and pseudorapidity η D ∗ are presented in the kinematic region 2 < p T D ∗ < 12 GeV and vbη D ∗ vb < 1.5 . They are compared to next-to-leading order (NLO) perturbative QCD calculations. The total cross-section for the process e +e − → e +e −c c in the anti-tagged mode is measured to be σ (e +e − → e +e −c c ) = (945 ± 239) pb with a direct contribution of σ (e +e − → e +e −c c ) dir = (392 ± 117) pb and a single-resolved contribution of σ (e +e − → e +e −c c ) res = (553 ± 184) pb.