Abstract
A precision measurement of jet cross sections in neutral current deep-inelastic scattering for photon virtualities 5.5 < Q2 < 80 GeV2 and inelasticities 0.2 < y < 0.6 is presented, using data taken with the H1 detector at HERA, corresponding to an integrated luminosity of 290 pbMINUS SIGN 1. Double-differential inclusive jet, dijet and trijet cross sections aremeasured simultaneously and are presented as a function of jet transverse momentum observables and as a function of Q2.
Jet cross sections normalised to the inclusive neutral current DIS cross section in the respective Q2- interval are also determined. Previous results of inclusive jet cross sections in the range 150 < Q2 < 15,000 GeV2 are extended to low transverse jet momenta 5 < Pjet T < 7GeV.
The data are compared to predictions from perturbative QCD in next-to-leading order in the strong coupling, in approximate next-to-next-to-leading order and in full next-to-nextto- leading order.Using also the recently publishedH1jet data at high values of Q2, the strong coupling constant αs (MZ ) is determined in next-to-leading order.