The B-physics potential of Lhcb, BTEV, ATLAS and CMS
Proceedings of Science 3 (1999)
Abstract:
The physics performance of the second generation B-physics experiments, LHCb, BTeV, ATLAS and CMS, is reviewed. The differences in detector philosophies, the CP-reach of the experiments, and the sensitivities to rare B decays are compared.The scale dependence of the hadron multiplicity in quark and gluon jets and a precise determination of CA /CF
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 449:3-4 (1999) 383-400
Abstract:
Data collected at the Z resonance using the DELPHI detector at LEP are used to determine the charged hadron multiplicity in gluon and quark jets as a function of a transverse momentum-like scale. The colour factor ratio, CA/CF, is directly observed in the increase of multiplicities with that scale. The smaller than expected multiplicity ratio in gluon to quark jets is understood by differences in the hadronization of the leading quark or gluon. From the dependence of the charged hadron multiplicity on the opening angle in symmetric three-jet events the colour factor ratio is measured to be: CA/CF = 2.246 ± 0.062(stat.) ± 0.080 (syst.) ± 0.095 (theo.) © 1999 Elsevier Science B.V. All rights reserved.W pair production cross-section and W branching fractions in e+e- interactions at 183 GeV
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 456:2-4 (1999) 310-321
Abstract:
The cross-section for the process e+e-→W+W- has been measured with the data sample collected by DELPHI at an average centre-of-mass energy of 182.65 GeV and corresponding to an integrated luminosity of 53 pb-1. Based on the 770 events selected as WW candidates, the cross-section for the doubly resonant process δ(e+e-→W+W-) = 15.86 ± 0.69 (stat) ± 0.26 (syst)pb has been measured and found to be in good agreement with the Standard Model expectation. The branching fractions of the W decay were also measured. From these a value of the CKM mixing matrix element \Vcs\ = 0.985 ± 0.073 (stat) ± 0.025 (syst) was derived. Our previously published WW cross-section measurements and the derived measurement of mW have been revised and updated with the present cross-section measurement to yield mW = 80.49 ± 0.43(stat) ± 0.09(syst) ± 0.03(LEP)GeV/c2. © 1999 Published by Elsevier Science B.V. All rights reserved.ZEUS results on the measurement and phenomenology of F2 at low cursive greek chi and low Q2
European Physical Journal C 7:4 (1999) 609-630
Abstract:
Measurements of the proton structure function F2 for 0.6 < Q2 < 17 GeV2 and 1.2 × 10-5 < cursive Greek chi < 1.9 × 10 -3 from ZEUS 1995 shifted vertex data are presented. From ZEUS F2 data the slopes dF2/d ln Q2 at fixed cursive Greek chi and din F2/d ln(1/cursive Greek chi) for cursive Greek chi < 0.01 at fixed Q2 are derived. For the latter, E665 data are also used. The transition region in Q2 is explored using the simplest non-perturbative models and NLO QCD. The data at very low Q2 ≤ 0.65 GeV2 are described successfully by a combination of generalised vector meson dominance and Regge theory. From a NLO QCD fit to ZEUS data the gluon density in the proton is extracted in the range 3 × 10-5 < cursive Greek chi < 0.7. Data from NMC and BCDMS constrain the fit at large cursive Greek chi. Assuming the NLO QCD description to be valid down to Q2 ∼ 1 GeV2, it is found that the qq̄ sea distribution is still rising at small cursive Greek chi and the lowest Q2 values whereas the gluon distribution is strongly suppressed.A precise measurement of the partial decay width ratio Rb0 = Γb(b)over-bar/Γhad
EUROPEAN PHYSICAL JOURNAL C 10:3 (1999) 415-442