118004066
Measurement of the inclusive jet cross section in proton-antiproton collisions at the center-of-mass energy of 1.96 TeV
This thesis studies the high-energy collisions of protons and antiprotons. The data used in the measurement were collected during 2004-2005 with the D0 detector at the Tevatron Collider of the Fermi National Accelerator Laboratory and correspond to 0.7 fb{sup -1} of integrated luminosity. High energy hadron collisions usually produce collimated sprays of particles called jets. The energy of the jets is measured using a liquid Argon-Uranium calorimeter and the production angle is determined with the help of silicon microstrip and scintillating fiber trackers. The inclusive jet cross section in proton-antiproton collisions is measured as a function of jet transverse momentum p{sub T} in six bins of jet rapidity at the center-of-mass energy {radical}s = 1.96 TeV. The measurement covers jet transerve momenta from 50 GeV up to 600 GeV and jet rapidities up to |y| = 2.4. The data are collected using a set of seven single jet triggers. Event and jet cuts are applied to remove non-physical backgrounds and cosmic-ray interactions. The data are corrected for jet energy calibration, cut and trigger efficiencies and finite jet p{sub T} resolution. The corrections are determined from data and the methods are tested with Monte Carlo simulation. The main experimental challenges inmore » the measurement are the calibration of jet energies and the determination of the jet p{sub T} resolution. New methods are developed for the jet energy calibration that take into account physical differences between the {gamma}+jet and dijet calibration samples arising from quark and gluon jet differences. The uncertainty correlations are studied and provided as a set of uncertainty sources. The production of particle jets in hadron collisions is described by the theory of quantum chromodynamics (QCD). When the transverse jet momentum is large, the contributions from long-distance physics processes are small and the production rates of jets can be predicted by perturbative QCD. The inclusive jet cross section in p{bar p} collisions at large p{sub T} is directly sensitive to the strong coupling constant ({alpha}{sub s}) and the parton distribution functions (PDFs) of the proton. This measurement can be used to constrain the PDFs, in particular the gluon PDF at high proton momentum fraction x, and to look for quark substructure at the TeV scale. The data are compared to the theory predictions with perturbative QCD in the next-to-leading order precision and a good agreement between data and theory is observed.« less
120859704
Results on inclusive jets and jet properties
We report on a measurement of the inclusive jet cross section in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV using data collected by the D0 experiment at the Fermilab Tevatron Collider corresponding to an integrated luminosity of 0.70 fb{sup -1}. Detailed studies of correlations between systematic uncertainties in transverse momentum and rapidity are presented, and the cross section measurements are found to be in good agreement with next-to-leading order QCD calculations.
119481210
D0 QCD studies
A number of recent measurements from D0 that can be used to constrain parton distributions and tune QCD Monte Carlo models are presented. The selection includes W charge asymmetry, Z+jet event properties, dijet azimuthal decorrelations and the inclusive jet cross section.
118899805
INCLUSIVE JET CROSS SECTION MEASUREMENT AT DØ
We present a new preliminary measurement of the inclusive jet cross section in pp̄ collisions based on a integrated luminosity of about 0.8 fb. The data were acquired using the DØ detector between 2002 and 2005. Jets are reconstructed using an iterative cone algorithm with radius Rcone = 0.7. The inclusive jet cross section is presented as a function of transverse jet momentum and rapidity. Predictions from perturbative QCD in next-to-leading order, plus threshold corrections in 2-loop accuracy describe the shape in the transverse jet momentum.
202114345
Probing QCD at high energy
potential sensitivity to new physics. The experimental systematics at the LHC are also becoming competitive with the Tevatron, making precision measurements of QCD possible. Measurements of inclusive jet, dijet and isolated prompt photon production can be used to test perturbative QCD predictions and to constrain parton distribution functions, as well as to measure the strong coupling constant. More exclusive topologies are used to constrain aspects of parton shower modeling, initial and final state radiation. Interest in boosted heavy resonances has resulted in novel studies of jet mass and subjet structure that also test perturbative QCD predictions and parton shower models. Studies of V+jets, including heavy flavor jets, constrain important backgrounds to single top, Higgs boson searches and new physics searches. At the highest mass scales, measurements of dijet mass and dijet angular distributions are sensitive probes of new physics.
119586383
Fast triggering with a plastic streamer tube calorimeter
Abstract We describe the use of the DELPHI Hadron Calorimeter, a plastic streamer tube detector, in conjunction with the DELPHI fast triggers. The essential parameters of this operation are the particle localization capability, affected by the charge diffusion on the graphite-coated cathode and the inherent noise of the streamer tubes. We present results of measurements of these features, performed on an installed calorimeter module, and give estimates of the fast trigger performance.
13355291
Novel Data Acquisition System for Silicon Tracking Detectors
We have developed a novel data acquisition system for measuring tracking parameters of a silicon detector in a particle beam. The system is based on a commercial Analog-to-Digital VME module and a PC Linux based Data Acquisition System. This DAQ is realized with C++ code using object-oriented techniques. Track parameters for the beam particles were reconstructed using off-line analysis code and automatic detector position alignment algorithm. The new DAQ was used to test novel Czochralski type silicon detectors. The important silicon detector parameters, including signal size distributions and signal to noise distributions, were successfully extracted from the detector under study. The efficiency of the detector was measured to be 95 %, the resolution about 10 µm, and the signal to noise ratio about 10.