The inclusive jet differential cross section has been measured for jet transverse energies, $E_T$, from 15 to 440 GeV, in the pseudorapidity region 0.1$\leq | \eta| \leq $0.7. The results are based on 19.5 pb$~{-1}$ of data collected by the CDF collaboration at the Fermilab Tevatron collider. The data are compared with QCD predictions for various sets of parton distribution functions. The cross section for jets with $E_T>200$\ GeV is significantly higher than current predictions based on O($\alpha_s~3$) perturbative QCD calculations. Various possible explanations for the high-$E_T$\ excess are discussed.
No description provided.
Properties of the hadronic final state in photoproduction events with large transverse energy are studied at the electron-proton collider HERA. Distributions of the transverse energy, jets and underlying event energy are compared to $\overline{p}p$ data and QCD calculations. The comparisons show that the $\gamma p$ events can be consistently described by QCD models including -- in addition to the primary hard scattering process -- interactions between the two beam remnants. The differential jet cross sections $d\sigma/dE_T~{jet}$ and $d\sigma/d\eta~{jet}$ are measured.
No description provided.
Additional overall systematic error of 26 pct.
Additional overall systematic error of 26 pct.
Inclusive jet differential cross sections for the reaction ep → jet + X at Q 2 below 4 GeV 2 have been measured with the ZEUS detector at HERA using an integrated luminosity of 0.55 pb −1 . These cross sections are given in the kinematic region 0.2 < y < 0.85, for jet pseudorapidities in the ep -laboratory range −1 < η jet < 2 and refer to jets at the hadron level with a cone radius of one unit in the η - θ plane. These results correspond to quasi-real photoproduction at centre-of-mass energies in the range 130–270 GeV and, approximately, for jet pseudorapidities in the interval −3 < η jet ( λp CMS) < 0. These measurements cover a new kinematic regime of the partonic structure of the photon, at typical scales up to ∼300 GeV 2 and photon fractional momenta down to x γ ∼ 10 −2 . Leading logarithm parton shower Monte Carlo calculations, which include both resolved and direct processes and use the predictions of currently available parametrisations of the photon parton distributions, describe in general the shape and magnitude of the measured η jet and E t jet distributions.
Second systematic error is uncertainty in the ET scale.
Second systematic error is uncertainty in the ET scale.
Second systematic error is uncertainty in the ET scale.
Measurements of the global transverse energy distributions dσ / dE T and dE T / dη using the new AGS beam of 197 Au at 11.6 A GeV/ c on a Au target, as well as a beam of 28 Si at 14.6 A GeV/ c on Al and Au targets, are presented for a leadglass detector with acceptance 1.3 ≤ η ≤ 2.4 and 0 ≤ φ < 2 π . The dσ / dE T spectra are observed to have different shapes for the different systems and simple energy rescaling does not account for the projectile dependence. The Au+Au dσ / dE T spectrum is satisfactorily constructed from the upper edge of Si+Au by the geometric Wounded Projectile Nucleon Model after applying a correction for the beam energy.
Incident energy is 14.6 GeV/nucleon.
Incident energy is 14.6 GeV/nucleon.
Incident energy is 11.6 GeV/nucleon.
The inclusive jet cross section in photoproduction has been measured as a function of transverse energy and pseudorapidity using the H 1 detector at the HERA electron-proton collider. The results are compared with leading order QCD calculations.
No description provided.
No description provided.
The results of two sets of transverse energy measurements, performed with incident proton beams of 200 and 450 GeV/c momentum on several nuclear targets, are presented. The transverse energy cross sections dσ/dET are measured in a pseudorapidity range including the target fragmentation region (−0.1<η<2.9) for both data sets and also in a nearly complete pseudorapidity coverage (−0.1<η<5.5) for the data taken at 200 GeV/c incident momentum. A comparison is made of the transverse energy distributions in the target fragmentation region and in the full η region. We find that the mean value of pseudorapidity of the dET/dη distributions shifts towards the target fragmentation region as the atomic mass number of the target increases or a selection of high transverse energy events is made. A parametrization based on a simple geometrical nucleonnucleon scattering approach was found to be inadequate to describe all features of the transverse energy distributions. Finally, the VENUS model is compared with the experimental data.
No description provided.
No description provided.
No description provided.
Inclusive jet cross sections have been measured in p¯p collisions at √s =546 and 1800 GeV, using the Collider Detector at Fermilab. The ratio of jet cross sections is compared to predictions from simple scaling and O(as3) QCD. Our data exclude scaling and lie (1.5–2.4)σ below a range of QCD predictions.
Additional systematic uncertainty +23,-26 pct.
Additional systematic uncertainty +-16 pct.
Additional systematic uncertainty +-0.22.
Muon-pair production has been measured in pCu, pU, OCu, OU and SU collisions at 200 GeV per nucleon. The cross sections are compatible with the atomic number dependence ( A proj. A targ. ) α where α =0.91±0.04 for the J/ψ resonance and α =1.01±0.04 for muon pairs produced in the mass continuum between 1.7 and 2.7 GeV/ c 2 .
Cross sections fitted with SIG0*(A(P=1)*A(P=2))** ALPHA. ALPHA is coded here as POWER(N=A*A,YN=SIG).
Cross sections fitted with SIG0*(A(P=1)*A(P=2))** ALPHA. ALPHA is coded here as POWER(N=A*A,YN=SIG).
No description provided.
We present a measurement of the inclusive jet cross section in p¯p collisions at √s =1.8 TeV at the Fermilab Tevatron using the Collider Detector at Fermilab. Good agreement is seen with the predictions of recent next-to-leading-order [O(αs3)] QCD predictions. The dependence of the cross section on clustering cone size is reported for the first time. An improved limit on Λc, a term characterizing possible quark substructure, is set at 1.4 TeV (95% C.L.).
Data are averaged over the pseudorapidity interval 0.1 to 0.7.
We report on a systematic study of midrapidity transverse energy production and forward energy flow in interactions of16O and32S projectiles with S, Cu, Ag and Au targets at 60 and 200 GeV/nucleon. The variation of the shape of theET distributions with target and projectile mass can be understood from collision geometry. AverageET values determined for central collisions show an increasing stopping power for heavier target nuclei. A higher relative stopping is observed at 60 GeV/nucleon than at 200 GeV/nucleon. Bjorken estimates of the energy density reach approximately 3 GeV/fm3 in highET events at 200 GeV/nucleon with16O and32S projectiles. The systematics of the data and the shapes ofET and pseudorapidity distributions are well described by the Lund model Fritiof.
No description provided.
No description provided.
No description provided.
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