The bb̄ production cross section and angular correlations in pp̄ collisions at √s = 1.8 TeV
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 487:3-4 (2000) 264-272
Abstract:
We present measurements of the bb̄ production cross section and angular correlations using the DO detector at the Fermilab Tevatron pp̄ Collider operating at √s = 1.8 TeV. The b quark production cross section for |y(b)| < 1.0 and p(T)/b > 6 GeV/c is extracted from single muon and dimuon data samples. The results agree in shape with the next-to-leading order QCD calculation of heavy flavor production but are greater than the central values of these predictions. The angular correlations between b and b̄ quarks, measured from the azimuthal opening angle between their decay muons, also agree in shape with the next-to-leading order QCD prediction. (C) 2000 Elsevier Science B.V.Limits on quark compositeness from high energy jets in p̄p collisions at 1.8 TeV
Physical Review D - Particles, Fields, Gravitation and Cosmology 62:3 (2000) 1-6
Abstract:
Events in p̄p collisions at √s= 1.8 TeV with total transverse energy exceeding 500 GeV are used to set limits on quark substructure. The data are consistent with next-to-leading order QCD calculations. We set a lower limit of 2.0 TeV at 95% confidence on the energy scale ΛLL for compositeness in quarks, assuming a model with a left-left isoscalar contact interaction term. The limits on ΛLL are found to be insensitive to the sign of the interference term in the Lagrangian. ©2000 The American Physical Society.Results from a new combined test of an electromagnetic liquid argon calorimeter with a hadronic scintillating-tile calorimeter
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 449:3 (2000) 461-477
Abstract:
A new combined test of an electromagnetic liquid argon accordion calorimeter and a hadronic scintillating-tile calorimeter was carried out at the CERN SPS. These devices are prototypes of the barrel calorimeter of the future ATLAS experiment at the LHC. The energy resolution of pions in the energy range from 10 to 300 GeV at an incident angle θ of about 12° is well described by the expression σ/E = ((41.9 ± 1.6)%/√E + (1.8 ± 0.1)%)⊕(1.8 ± 0.1)/E, where E is in GeV. The response to electrons and muons was evaluated. Shower profiles, shower leakage and the angular resolution of hadronic showers were also studied. Results are compared with those from the previous beam test.Spin correlation in tt̄ production from pp̄ collisions at √s = 1.8 TeV
Physical Review Letters 85:2 (2000) 256-261
Abstract:
An analytical study was carried out to account for spin correlation effects in the production of tt̄ pairs in pp̄ collisions at √s=1.8 TeV. It was found that κ > -0.25 at the 68% confidence level.Measurement of the W-->taunu production cross section in pp collisions at square root s=1.8 TeV.
Phys Rev Lett 84:25 (2000) 5710-5715