The transverse momentum and total cross section of e^+e^- pairs in the Z-boson region of 66<M_{ee}<116 GeV$/c^2$ from $p\bar{p}$ collisions at $\sqrt{s}=1.8$ TeV are measured using 110 pb^{-1} of collisions taken by the Collider Detector at Fermilab during 1992-1995. The total cross section is measured to be $248 \pm 11$ pb. The differential transverse momentum cross section is compared with calculations that match quantum chromodynamics perturbation theory at high transverse momentum with the gluon resummation formalism at low transverse momentum.
The measured transverse momentum distribution of e+e- pairs in the Z0 bosonregion. PT is the centre of the bins.
The total cross section for e+e- pair production in the Z0 region. The mainerror is the statistical and efficiency error, the first DSYS error is the syst ematic error from the background subtractions and the second DSYS error is from the collision luminosity.
We present a study of J/ψ and ψ(2S) production in pp¯ collisions, at s=1.8TeV with the CDF detector at Fermilab. The J/ψ and ψ(2S) mesons are reconstructed using their μ+μ− decay modes. We have measured the inclusive production cross section for both mesons as a function of their transverse momentum in the central region, |η|<0.6. We also measure the fraction of these events originating from b hadrons. We thus extract individual cross sections for J/ψ and ψ(2S) mesons from b-quark decays and prompt production. We find a large excess (approximately a factor of 50) of direct ψ(2S) production compared with predictions from the color singlet model.
Integrated cross sections.
Differential cross section times branching ratio for J/PSI's originating from b hadron decays.
Differential cross section times branching ratio for PSI(2S) originating from b hadron decays.
We have measured the fraction of J/ψ mesons originating from χc meson decays in pp¯ collisions at s=1.8TeV. The fraction, for PTJ/ψ>4.0GeV/c and |ηJ/ψ|<0.6, not including contributions from b flavored hadrons, is 29.7%±1.7%(stat)±5.7%(syst). We have determined the cross sections for J/ψ mesons originating from χc decays and for directly produced J/ψ mesons. We have found that direct J/ψ production is in excess of the prediction of the color singlet model by the same factor found for direct ψ(2S) production.
Fraction of J/PSI mesons from CHI/C decays, excluding the the contributions from b-hadron decay.
Differential cross section for J/PSI's directly produced (ie excluding CHI/C and PSI/(25) decay contribution to the prompt production cross section). RE = PBAR P --> J/PSI X.
Differential cross section for J/PSI's produced in CHI/C decays.
This paper presents the first direct measurement of the $B$ meson differential cross section, $d\sigma/dp_T$, in $p\overline{p}$ collisions at $\sqrt{s}=1.8$ TeV using a sample of $19.3 \pm 0.7$ pb$~{-1}$ accumulated by the Collider Detector at Fermilab (CDF). The cross section is measured in the central rapidity region $|y| < 1$ for $p_T(B) > 6.0$ GeV/$c$ by fully reconstructing the $B$ meson decays $B~{+}\rightarrow J/\psi K~{+}$ and $B~{0}\rightarrow J/\psi K~{*0}(892)$, where $J/\psi \rightarrow \mu~+\mu~-$ and $K~{*0} \rightarrow K~+ \pi~-$. A comparison is made to the theoretical QCD prediction calculated at next-to-leading order.
Charged B meson cross section.
Average B meson cross section (including charged and neutral).
Total integrated B meson cross section above 6 GeV.
Measurements of the inclusive cross-sections forK0 and Λ production in hadronic decays of the Z are presented together with measurements of two-particle correlations within pairs of Λ andK0. The results are compared with predictions from the hadronization models Jetset, based on string fragmentation, and Herwig, based on cluster decays. TheK0 spectrum is found to be harder than predicted by both models, while the Λ spectrum is softer than predicted. The correlation measurements are all reproduced well by Jetset, while Herwig misses some of the qualitative features and overestimates the size of the\(\Lambda \bar \Lambda \) correlation. Finally, the possibility of Bose-Einstein correlation in theKS0KS0 system is discussed.
No description provided.
No description provided.
No description provided.
A search for pairs of highpT prompt photons produced in hydrogen by a 280 GeV/c incidentπ- beam has been carried out using a fine-grained electromagnetic calorimeter and the Omega spectrometer at the CERN SPS. Clear evidence for the existence of such events is found with a six standard deviation signal forpT>3.0 GeV/c. The cross-sections are consistent with beyond leading order QCD calculations. A discussion on the determination of αs is also presented.
PT is the transverse momentum of either of the two photons.
PT is the transverse momentum of either of the two photons.
We present results on the jet structure observed in multihadronic events produced by e+e− annihilation in the Mark I magnetic detector at SPEAR. The evidence for jet structure and the jet-axis angular distribution are reported. We give inclusive distributions of the hadrons in Feynman x, rapidity, and transverse momentum relative to the jet axis.
Observed particle PT with respect to jet axis for events with three or more detected charged particles.
No description provided.
No description provided.
Forum