A Study of Jet Rates and Measurement of Α{sub S} at the Z° Resonance
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Published: 1992
Total Pages: 14
ISBN-13:
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Author:
Publisher:
Published: 1992
Total Pages: 14
ISBN-13:
DOWNLOAD EBOOKAuthor:
Publisher:
Published: 1992
Total Pages: 14
ISBN-13:
DOWNLOAD EBOOKWe present jet rates in hadronic decays of Z[sup 0] bosons measured by the SLD experiment at SLAC. The data are analyzed in terms of the JADE and recently proposed Durham algorithms, and are found to be in agreement with similar measurements by the LEP experiments, and also with the predictions of perturbative QCD and fragmentation Monte Carlo models of hadron production. After correction for hadronization effects the 2, 3 and 4-jet rates are well described by [Omicron]([alpha][sub s][sup 2]) perturbative QCD calculations. From fits to the differential 2-jet distribution the strong coupling [alpha][sub s](M[sub Z]) is measured to be [alpha][sub s](M[sub Z]) = 0.119 [plus minus] 0.002(stat.) [plus minus] 0.003(exp.syst.) [plus minus] 0.014(theory) (preliminary). The largest contribution to the error arises from the theoretical uncertainty in choosing the QCD renormalization scale.
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Published: 1993
Total Pages: 156
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DOWNLOAD EBOOKThis experiment was performed with the SLD detector at the Stanford Linear Accelerator Center. Only charged tracks measured in the central drift chamber were used for the measurement of the jet production rates. The value of the strong coupling?{sub s}(M{sub Z}{sup o}) is determined from the production rates of jets in hadronic Z° decays in e e− annihilations. The relative jet rates are obtained using the JADE-type algorithms. The results are compared with the jet rates obtained from a new jet algorithm proposed by N. Brown et al. called the D̀̀urham ̀̀algorithm. The data can be well described by O(?{sub s}2) QCD calculations and by QCD shower model calculations. A fit of the theoretical predictions to the data taken with the SLD yields a value,?{sub s}(M{sub Z}{sup o}) = 0.120 ± 0.002(stat.) ± 0.003(exp.){sub -0.009}{sup +0.011}(theor.). The error is dominated by the theoretical uncertainties. The measurement is compared with results from other experiments and it is shown that the value obtained for?{sub s} agrees well with these results and furthermore supports the evidence for the running of the strong coupling, consistent with the non-Abelian nature of QCD. The Stanford Linear Collider (SLC) can deliver partially longitudinally polarized electrons to the interaction point. Jet production rates and values for?{sub s} are calculated both for right-handed and left-handed initial state electrons. All results are consistent with the unpolarized result, as predicted by the Standard Model.
Author: Jan A. Lauber
Publisher:
Published: 1993
Total Pages: 156
ISBN-13:
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Published: 1992
Total Pages: 14
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DOWNLOAD EBOOKWe present jet rates in hadronic decays of Z° bosons measured by the SLD experiment at SLAC. The data are analyzed in terms of the JADE and recently proposed Durham algorithms, and are found to be in agreement with similar measurements by the LEP experiments, and also with the predictions of perturbative QCD and fragmentation Monte Carlo models of hadron production. After correction for hadronization effects the 2, 3 and 4-jet rates are well described by [Omicron]([alpha]{sub s}2) perturbative QCD calculations. From fits to the differential 2-jet distribution the strong coupling [alpha]{sub s}(M{sub Z}) is measured to be [alpha]{sub s}(M{sub Z}) = 0.119 ± 0.002(stat.) ± 0.003(exp.syst.) ± 0.014(theory) (preliminary). The largest contribution to the error arises from the theoretical uncertainty in choosing the QCD renormalization scale.
Author: Jan A. Lauber
Publisher:
Published: 1993
Total Pages: 312
ISBN-13:
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Published: 2012
Total Pages:
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DOWNLOAD EBOOKMeasurements of jet production rates in association with W and Z bosons for jet transverse momenta above 30 GeV are reported, using a sample of proton-proton collision events recorded by CMS at sqrt(s) = 7 TeV, corresponding to an integrated luminosity of 36 inverse picobarns. The study includes the measurement of the normalized inclusive rates of jets sigma(V +>= n jets)/sigma(V), where V represents either a W or a Z. In addition, the ratio of W to Z cross sections and the W charge asymmetry as a function of the number of associated jets are measured. A test of Berends--Giele scaling at sqrt(s) = 7 TeV is also presented. The measurements provide a stringent test of perturbative-QCD calculations and are sensitive to the possible presence of new physics. The results are in agreement with the predictions of a simulation that uses explicit matrix element calculations for final states with jets.
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Published: 1997
Total Pages: 11
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DOWNLOAD EBOOKThe authors present a new preliminary measurement of the parity-violation parameter A{sub b} using a self-calibrating jet-charge technique. In the SLD experiment they observe hadronic decays of Z° bosons produced in collisions between longitudinally polarized electrons and unpolarized positrons a the SLAC Linear Collider. A sample of b{anti b} events is selected using the topologically reconstructed mass of B hadrons. From the 1997--1998 data sample of approximately 200,000 hadronic Z° decays, they obtain A{sub b} = 0.824 " 0.031(stat) " 0.032(syst). Together with the previous 1993--1995 result, it yields a preliminary combined SLD jet-charge measurement of: A{sub b} = 0.849 " 0.026(stat) " 0.031(syst).
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Published: 2014
Total Pages: 127
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DOWNLOAD EBOOKThis study presents the measurement of the rapidity distributions in events containing a Z boson and a jet in proton-proton collisions at a center-of-mass energy of 7 TeV. The data correspond to an integrated luminosity of approximately 5 fb-11, recorded by the CMS detector at the Large Hadron Collider (LHC). The measured angular distributions are compared with the predictions from next-to-leading order perturbative QCD calculations and two generator programs that combine tree-level matrix element calculations with parton showers. We also present a measurement of jet production rates in association with a Z boson using data recorded at a center-of-mass energy of 8 TeV and with an integrated luminosity of 19.8 fb-1. This measurement provides a stringent test of perturbative QCD calculations, and the result is compared with predictions from theoretical calculations.
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Published: 1976
Total Pages: 1042
ISBN-13:
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