Measurement of charm and beauty dijet cross sections in photoproduction at HERA using the H1 vertex detector

Universität Wuppertal Rechenzentrum Wuppertal Germany Wuppertal Germany
European Physical Journal C (Impact Factor: 5.44). 08/2006; 47(3):597-610. DOI: 10.1140/epjc/s2006-02616-5

ABSTRACT A measurement of charm and beauty dijet photoproduction cross sections at the ep collider HERA is presented. Events are selected
with two or more jets of transverse momentum pt
jet1(2)>11(8) GeV in the central range of pseudo-rapidity -0.9<ηjet1(2)<1.3. 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 central vertex detector. Differential dijet
cross sections for charm and beauty, and their relative contributions to the flavour inclusive dijet photoproduction cross
section, are measured as a function of the transverse momentum of the leading jet, the average pseudo-rapidity of the two
jets and the observable xγ
obs. Taking into account the theoretical uncertainties, the charm cross sections are consistent with a QCD calculation in next-to-leading
order, while the predicted cross sections for beauty production are somewhat lower than the measurement.

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