Jet cross sections were measured in charged current deep inelastic e+-p scattering at high boson virtualities Q^2 with the ZEUS detector at HERA II using an integrated luminosity of 0.36 fb^-1. Differential cross sections are presented for inclusive-jet production as functions of Q^2, Bjorken x and the jet transverse energy and pseudorapidity. The dijet invariant mass cross section is also presented. Observation of three- and four-jet events in charged-current e+-p processes is reported for the first time. The predictions of next-to-leading-order (NLO) QCD calculations are compared to the measurements. The measured inclusive-jet cross sections are well described in shape and normalization by the NLO predictions. The data have the potential to constrain the u and d valence quark distributions in the proton if included as input to global fits.
Differential polarized inclusive jet cross sections as a function of jet pseudorapidity.
Differential polarized inclusive jet cross sections as a function of jet pseudorapidity.
Differential polarized inclusive jet cross sections as a function of jet transverse energy.
The production rates and substructure of jets have been studied in charged current deep inelastic e+p scattering for Q**2>200 GeV**2 with the ZEUS detector at HERA using an integrated luminosity of 110.5 pb**-1. Inclusive jet cross sections are presented for jets with transverse energies E_T(jet) > 14 GeV and pseudorapidities in the range -1 < eta(jet) < 2. Dijet cross sections are presented for events with a jet having E_T(jet) > 14 GeV and a second jet having E_T(jet) > 5 GeV. Measurements of the mean subjet multiplicity, <n_sbj>, of the inclusive jet sample are presented. Predictions based on parton-shower Monte Carlo models and next-to-leading-order QCD calculations a re compared to the measurements. The value of alphas(M_Z), determined from <n_sbj> at y_cut=0.01 for jets with 25<E_T(jet)<119 GeV, is alphas(M_Z) = 0.1202 +-0.0052 (stat.) +0.0060-0.0019 (syst.) +0.0065-0.0053 (th.). The mean subjet multiplicity as a function of Q**2 is found to be consistent with that measured in NC DIS.
Inclusive jet cross section DSIG/DQ**2 for jets in the lab. frame. Data from the 1995-1997 sample.
Inclusive jet cross section DSIG/DQ**2 for jets in the lab. frame. Data from the 1999-2000 sample.
Inclusive jet cross section DSIG/DQ**2 for jets in the lab. frame. Data from the combined sample.
The shapes of jets with transverse energies, E_T(jet), up to 45 GeV produced in neutral- and charged-current deep inelastic e+p scattering (DIS) at Q**2 > 100 GeV**2 have been measured with the ZEUS detector at HERA. Jets are identified using a cone algorithm in the eta-phi plane with a cone radius of one unit. The jets become narrower as E_T(jet) increases. The jet shapes in neutral- and charged-current DIS are found to be very similar. The jets in neutral-current DIS are narrower than those in resolved processes in photoproduction and closer to those in direct-photon processes for the same ranges in E_T(jet) and jet pseudorapidity. The jet shapes in DIS are observed to be similar to those in e+e- interactions and narrower than those in pbarp collisions for comparable E_T(jet). Since the jets in e+e- interactions and e+p DIS are predominantly quark initiated in both cases, the similarity in the jet shapes indicates that the pattern of QCD radiation within a quark jet is to a large extent independent of the hard scattering process in these reactions.
Measured differential jet shapes, corrected to the hadron level, in neutral-current DIS for jets with ET greater than 14 GeV in different etarap regions.
Measured differential jet shapes, corrected to the hadron level, in neutral-current DIS for jets with ET greater than 14 GeV in different etarap regions.
Measured differential jet shapes, corrected to the hadron level, in neutral-current DIS for jets with ET greater than 14 GeV in different etarap regions.