G. Abbiendi et al., Inclusive production of D*(+/-) mesons in photon-photon collisions at roots(ee) 183 and 189 GeV and a first measurement of F-2,c(gamma), EUR PHY J C, 16(4), 2000, pp. 579-596
The inclusive production of D*(+/-) mesons in photon-photon collisions has
been measured using rile OPAL detector at LEP at e(+)e(-) centre-of-mass en
ergies root S-ee of 183 and 189 GeV. The D*(+) mesons are reconstructed in
their decay to D(0)pi(+) with the D-0 observed in the two decay modes K(-)p
i(+) and K(-)pi(+)pi(-)pi(+) After background subtraction, 100.4 +/- 12.6 (
stat) D*(+/-) mesons have been selected in events without observed scattere
d beam electron ("anti-tagged") and 29.8 +/- 5.9 (stat)D*(+/-) mesons in ev
ents where one beam electron is scattered into the detector ("single-tagged
"). Direct and single-resolved events are studied separately. Differential
cross-sections d sigma/dp(T)(D*) and d sigma/d \eta(D*)\ as functions of th
e D*+/- transverse momentum p(T)(D*) and pseudorapidity eta(D*) are present
ed in the kinematic region 2 GeV < p(T)(D*) < 12 GeV and \eta(D*)\ < 1.5 Th
ey are compared to next-to-leading order (NLO) perturbative QCD calculation
s. The total cross-section for the process e(+)e(-) --> e(+)e(-) c (c) over
bar where the charm quarks are produced in the collision of two quasi-real
photons is measured to be sigma(e(+)e(-) --> e(+)e(-) c (c) over bar) = 96
3 +/- 110 (stat) +/- 86 (sys) +/- 224 (extrapolation) pb. A first measureme
nt. of the charm structure function F-2.0(gamma), of the photon is performe
d in the kinematic range 0.0014 < x < 0.87 and 5 GeV2 < Q(2) < 100 GeV2. an
d the result is compared to a NLO perturbative QCD calculation.