The production and semi-leptonic decay of heavy quarks have been studied in the photoproduction process e(+)p -> e(+) + dijet + e(-) + X with the ZEUS detector st HERA using an integrated luminosity of 38.5 pb(-1). Events with photon-proton centre-of-mass energies, W(gammap), between 134 and 289 GeV and a photon virtuality, Q(2), less than 1 GeV(2) were selected requiring at least two jets of transverse energy E(T)(jet(2)) > 7(6) GeV and an electron in the final state. The electrons were identified by employing the ionisation energy loss measurement. The contribution of beauty quarks was determined using the transverse momentum of the electron relative to the axis of the closest jet, p(T)(rol). The data, after background subtraction, were fit with a Monte Carlo simulation including beauty and charm decays, The measured beauty cross section was extrapolated to the parton level with the b quark restricted to the region of tranverse momentum p(T)(b) > p(T)(min) = 5 GeV and pseudorapidity \ eta (b)\ < 2 The extrapolated cross section is 1.6 +/- 0.4 (stat.)(-0.5)(+0.3), (syst.)(-0.4)(+0.2) (ext.) nb. The result is compared to a perturbative QCD calculation performed to next-to-leading order.
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|Titolo:||Measurement of open beauty production in photoproduction at HERA RID B-9165-2008 RID C-5889-2009 RID C-2169-2008 RID A-4818-2008|
|Data di pubblicazione:||2001|
|Appare nelle tipologie:||1.1 Articolo in rivista|