Measurement of the double differential dijet rate in deep inelastic scattering at HERA and comparison to NLO QCD calculations

The analysis presented the measurement of the dijet rate R2, the fraction of dijet events in all DIS events, as a function of the kinematic variables xB and Q2 in the range of 5 < Q2 < 100 GeV2 and 10-4 < xB < 10-2. The analysis is based on data collected with the H1 detector in the years 1996/97. The large amount of integrated luminosity (21.9 pb-1) available for this analysis allowed for the first time a double differential measurement of R2 as a function of both xB and Q2. The single differential dijet rate, R2(xB) and R2(Q2), increases for increasing Q2 as well as for increasing xB. The double differential dijet rate R2(xB, Q2) is more sensitive to the xB dependence of dijet production since it shows a strong increase towards small values of xB if Q2 is kept fixed. The double differential dijet rate has been compared to predictions of NLO QCD calculations. For the comparison it is required that at least one of the jets has a transverse energy 5 + Δ GeV where Δ = 2 GeV was chosen to be the central cut scenario. The dijet rate is well described by NLO calculations when μr2 = Q2 is chosen as the renormalization scale albeit at the cost of large scale uncertainties. If, however, μr2 = Q2 + Et2 is chosen, which considerable reduces the scale uncertainties, substantial contributions from other sources of dijet production are needed. (orig.)