Measurement of F2c[`(c)]F2ccˉ and F2b[`(b)]F2bbˉ at low Q2 and x * using the H1 vertex detector at HERA

Abstract

Measurements are presented of inclusive charm and beauty cross sections in e +p collisions at HERA for values of photon virtuality 12 ≤ Q2 ≤ 60 GeV2 and of the Bjorken scaling variable 0.0002 x ≤ 0.005. The fractions of events containing charm and beauty quarks are determined using a method based on the impact parameter, in the transverse plane, of tracks to the primary vertex, as measured by the H1 vertex detector. Values for the structure functions Fcc¯2 and Fbb¯2 are obtained. This is the first measurement of Fbb¯2 in this kinematic range. The results are found to be compatible with the predictions of perturbative quantum chromodynamics and with previous measurements of Fcc¯2.