Download or read book A Preliminary Improved Measurement of the B Hadron Energy Distribution in Z Decays written by and published by . This book was released on 1998 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors have measured the B hadron energy distribution in Z° decays using a new technique applied to a sample of inclusive B decays recorded in the SLD experiment at SLAC between 1996 and 1997. The upgraded CCD vertex detector is used to reconstruct B-decay vertices with high efficiency and purity, and to provide precise measurements of the kinematic quantities used in this technique. For each reconstructed B-decay vertex, the part of the B energy missing from the vertex is derived from the kinematic quantities. B vertices with low missing mass are selected to provide a very high purity sample and to obtain good energy resolution. The authors compare the scaled B hadron energy distribution with the predictions of several QCD and phenomenological models of heavy quark fragmentation. The average scaled energy x{sub B} is measured to be 0.719"0.005 (stat.)"0.001 (unfolding) (preliminary).

Download or read book An Improved Measurement of the B Quark Fragmentation Function in Z Decays at SLD written by and published by . This book was released on 1999 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present preliminary results of a new measurement of the b quark fragmentation function in Z° decays using a novel kinematic B hadron energy reconstruction technique. The measurement is performed using 150,000 hadronic Z° events recorded in the SLD experiment at SLAC between 1996 and 1997. The small and stable SLC beam spot and the CCD-based vertex detector are used to reconstruct topological B-decay vertices with high efficiency and purity, and to provide precise measurements of the kinematic quantities used in this technique. We measure the B energy with good efficiency and resolution over the full kinematic range. We compare the scale B hadron energy distribution with several functional forms of the B hadron energy distribution and predictions of several models of b quark fragmentation. Several functions including JETSET + Peterson are excluded by the data. The average scaled energy of the weakly decaying B hadron is measured to be x{sub B} = 0.719 " 0.005 (stat) " 0.007 (syst) " 0.001 (model) (preliminary).

Download or read book Improved Measurement of the B quark Fragmentation Function in Z0 Decays written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present preliminary results of an improved measurement of the inclusive b quark fragmentation function in Z0 decays using a novel kinematic B hadron energy reconstruction technique. The measurement is performed using 350,000 hadronic Z° events recorded in the SLD experiment at SLAC between 1997 and 1998. The small and stable SLC beam spot and the CCD-based vertex detector are used to reconstruct topological B-decay vertices with high efficiency and purity, and to provide precise measurements of the kinematic quantities used in this technique. They measure the B energy with good efficiency and resolution over the full kinematic range. They compare the measured scaled B hadron energy distribution with predictions of several models of b quark fragmentation and several functional forms of the B hadron energy distribution. Many of these are excluded by the data. The average scaled energy of the weakly decaying B hadron is measured to be x{sub B} = 0.710 " 0.003 (stat) " 0.005 (syst) " 0.004 (model) (preliminary).

Download or read book Measurement of the B Quark Fragmentation Function in Z Decays written by and published by . This book was released on 1999 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present preliminary results of a new measurement of the inclusive b quark fragmentation function in Z° decays using a novel kinematic B hadron energy reconstruction technique. The measurement is performed using 150,000 hadronic Z° events recorded in the SLD experiment at SLAC between 1996 and 1997. The small and stable SLC beam spot and the CCD-based vertex detector are used to reconstruct topological B-decay vertices with high efficiency and purity, and to provide precise measurements of the kinematic quantities used in this technique. We measure the B energy with good efficiency and resolution over the full kinematic range. We compare the measured scaled B hadron energy distribution with several functional forms of the B hadron energy distribution and predictions of several models of b quark fragmentation. Several functions are excluded by the data. The average scaled energy of the weakly decaying B hadron is measured to be x{sub B} = 0.714 " 0.005 (stat) " 0.007 (syst) " 0.002 (model) (preliminary).

Download or read book Measurement of the B Quark Fragmentation Function in Z0 Decays and First Measurement of B Bbar Energy Correlations written by and published by . This book was released on 2001 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present preliminary results of a new measurement of the inclusive b quark fragmentation function in Z° decays using a novel kinematic B hadron energy reconstruction technique. The measurement is performed using 350,000 hadronic Z° events recorded in the SLD experiment at SLAC between 1997 and 1998. The small and stable SLC beam spot and the CCD-based vertex detector are used to reconstruct topological B-decay vertices with high efficiency and purity, and to provide precise measurements of the kinematic quantities used in this technique. We measure the B energy with good efficiency and resolution over the full kinematic range. We compare the measured scaled B hadron energy distribution with several functional forms of the B hadron energy distribution and predictions of several models of b quark fragmentation. Several functions are excluded by the data. The average scaled energy of the weakly decaying B hadron is measured to be x{sub B} = 0.710 " 0.003 (stat) " 0.005 (syst) " 0.004 (model) (preliminary). In addition, we reconstruct the decay vertices of both the leading B and hadrons in a large sample of events, and measure their energies. We present the first (preliminary) measurement of the correlation between the B and energies in Z° --> b{bar b} events, and compare with the leading order QCD prediction.

Download or read book A Preliminary Measurement of the B Quark Fragmentation Function in Hadronic Z sup 0 Decays written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the[ital b] quark fragmentation function from a sample of semi-leptonic[bold B] decays collected between 1993 and 1995 in the SLD experiment at SLAC. The energy of each tagged[bold B] hadron was reconstructed using information from the lepton and a partially reconstructed charm decay vertex. A comparison of the scaled energy distribution with several phenomenological models of heavy quark fragmentation was made, using the same model in each case to correct the data. The average scaled energy was found to be[l-angle][chi][sub E][r-angle]= 0.697[+-]0.012([ital stat])[sup+0. 028][sub -0.024] ([ital syst])(preliminary).

Download or read book Measurement of the B Quark Fragmentation Function in Z0 Decays written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the b-quark inclusive fragmentation function in Z° decays using a novel kinematic B-hadron energy reconstruction technique. The measurement was performed using 350,000 hadronic Z° events recorded in the SLD experiment at SLAC between 1997 and 1998. The small and stable SLC beam spot and the CCD-based vertex detector were used to reconstruct B-decay vertices with high efficiency and purity, and to provide precise measurements of the kinematic quantities used in this technique. We measured the B energy with good efficiency and resolution over the full kinematic range. We compared the scaled B-hadron energy distribution with models of b-quark fragmentation and with several ad hoc functional forms. A number of models and functions are excluded by the data. The average scaled energy of weakly-decaying B hadrons was measured to be x{sub b} = 0.709 " 0.003 (stat) " 0.003 (syst) " 0.002 (model).

Download or read book Measurement of the Doubly Inclusive B bbar Quark Fragmentation Function in Z0 Decays and First Measurement of Angle Dependent B Bbar Energy Correlation written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present preliminary results of a measurement of the double-inclusive b quark fragmentation function in Z° decays using a novel kinematic B hadron energy reconstruction technique. The measurement is performed using 350,000 hadronic Z° events recorded in the SLD experiment at SLAC between 1996 and 1998. The small and stable SLC beam spot and the CCD-based vertex detector are used to reconstruct topological B-decay vertices with high efficiency and purity, and to provide precise measurements of the kinematic quantities used in this technique. We measure the B energy with good efficiency and resolution over the full kinematic range. We present a preliminary measurement of the angle dependent correlations between the B and {bar B} hadron energies in Z° b{bar b} events, and compare with the leading order QCD predictions.

Download or read book Measurement of the First and Second Moments of the Hadronic Mass Distribution in Semileptonic B Decays written by and published by . This book was released on 2003 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report a preliminary measurement of the first and second moments of the hadronic mass distributions in B → X{sub c}l[nu] decays. The measurements are based on [Upsilon](4S) → B{bar B} events where the hadronic decay of one of the B mesons is fully reconstructed and a charged lepton from the decay of the other B meson is identified. The moments are presented for threshold lepton momenta ranging from 0.9 to 1.6 GeV. From the M{sub X}2 moments we determine the non-perturbative Heavy Quark Expansion (HQE) parameters, {bar {Lambda}} and [lambda]1. We combine the measured moments M{sub X}2 with earlier BABAR measurements of the semileptonic branching ratios and B lifetimes and perform a simultaneous fit to the HQE for the moments obtained for different threshold lepton momenta and the semileptonic decay width. This fit results in an improved value for the CKM matrix element.

Download or read book Fermilab Meeting Dpf 92 The Proceedings Of The 7th Meeting Of The Aps Division Of Particles And Fields In 2 Volumes written by C H Albright and published by World Scientific. This book was released on 1993-06-01 with total page 1955 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings cover the latest results in Tevatron Collider Physics, LEP results, and results from other High Energy Physics Laboratories. The volume will consist of plenary and parallel contributions on the following subjects: Heavy Quark Physics, Physics Beyond the Standard Model, Astrophysics and Non-Accelerator Physics.

Download or read book Precise Measurement of the B quark Fragmentation Function in Z Boson Decays written by and published by . This book was released on 1999 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors have developed a new technique for inclusive reconstruction of the energy of B hadrons. The excellent efficiency and resolution of this technique allow them to make the most precise determination of the b-quark fragmentation function, using ee− {r{underscore}arrow} Z° decays recorded in the SLD experiment at SLAC. The authors compared their measurement with the predictions of a number of fragmentation models. The authors excluded several of these models and measured the average scaled energy of weakly-decaying B hadrons to be (x{sub B}) = 0.714"0.005(stat)"0.007(syst)"0.002 (model-dependence).

Download or read book Measurement of the Z boson Branching Fraction Into Hadrons Containing Bottom Quarks written by and published by . This book was released on 1990 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: We use the Mark II detector to study Z decays into bottom quark-anti-quark pairs, leading to the production of bottom hadrons. The Z bosons are formed in ee− annihilation at the SLC at center-of-mass energies between 89 and 93 GeV. We identify events containing semileptonic decays of bottom hadrons by detecting isolated leptons, i.e leptons with high transverse momenta relative to the nearest hadronic jet. Using isolated electrons and muons, we measure the B-hadron semileptonic branching ratio times the fraction of hadronic Z decays which contain bottom hadrons, B(B 2!Xl[nu]){center dot}[Gamma](Z 2!b{bar b})/[Gamma](Z 2!had) = 0.025 {sub -0.009}{sup +0.100} {plus minus} 0.005, where we have listed the statistical errors followed by the systematic error. Assuming B(B 2!X(ell)[nu]) = 11% {plus minus} 1%, we measure [Gamma](Z 2!b{bar b})/[Gamma](Z 2!had) = 0.23 {sub -0.09}{sup +0.11}, in good agreement with the standard-model prediction of 0.22. We find [Gamma](Z 2!b{bar b}) = 0.40 {sub -0.16}{sup +0.19} GeV. 83 refs., 34 figs., 19 tabs.

Download or read book Proceedings Of The 29th International Conference On High Energy Physics Ichep 98 In 2 Volumes written by Alan Astbury and published by World Scientific. This book was released on 1999-06-11 with total page 1899 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings consist of plenary rapporteur talks covering topics of major interest to the high energy physics community and parallel sessions papers which describe recent research results and future plans.

Download or read book Measurements of Moments of the Hadronic Mass Distribution in Semileptonic B Decays written by and published by . This book was released on 2004 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report a measurement of the first four moments of the hadronic mass distribution in {bar B} → X{sub c}l− {bar {nu}} decays. The measurements are based on 89 million [Upsilon](4S) → B{bar B} events where the hadronic decay of one of the B mesons is fully reconstructed and a charged lepton from the decay of the other B meson is identified. The moments are presented for minimum lepton momenta ranging from 0.9 to 1.6 GeV in the B rest frame. It is expected that such measurements will lead to improved determinations of.

Download or read book Measurement of the Bottom Hadron Lifetime at the Z sup 0 Resonancce written by and published by . This book was released on 1992 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have measured the bottom hadron lifetime from b{bar b} events produced at the Z° resonance. Using the precision vertex detectors of the Mark II detector at the Stanford Linear Collider, we developed an impact parameter tag to identify bottom hadrons. The vertex tracking system resolved impact parameters to 30?m for high momentum tracks, and 70?m for tracks with a momentum of 1 GeV. We selected B hadrons with an efficiency of 40% and a sample purity of 80%, by requiring there be at least two tracks in a single jet that significantly miss the Z° decay vertex. From a total of 208 hadronic Z° events collected by the Mark II detector in 1990, we tagged 53 jets, of which 22 came from 11 double-tagged events. The jets opposite the tagged ones, referred as the ù̀ntagged ̀̀sample, are rich in B hadrons and unbiased in B decay times. The variable?? is the sum of impact parameters from tracks in the jet, and contains vital information on the B decay time. We measured the B lifetime from a one-parameter likelihood fit to the untagged?? distribution, obtaining?{sub b} = 1.53{sub −0.45}{sup +0.55}±0.16 ps which agrees with the current world average. The first error is statistical and the second is systematic. The systematic error was dominated by uncertainties in the track resolution function. As a check, we also obtained consistent results using the?? distribution from the tagged jets and from the entire hadronic sample without any bottom enrichment.

Download or read book Measurement of the Average Lifeetime of B Hadrons at SLD written by and published by . This book was released on 1994 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present preliminary measurements of the average B hadron lifetime using a sample of 50,000 Z° events collected by SLD at the SLC in 1993. Their first technique uses the impact parameter of tracks in jets opposite tagged b jets. They obtain [tau]{sub B}([delta]) = 1.617 ± 0.048 ± 0.086 ps, and [tau]{sub B}([Sigma][delta]) = 1.627 ± 0.054 ± 0.132 ps from single and summed impact parameter distributions. The second technique uses inclusive vertices reconstructed in three dimensions. From the decay length distribution, they extract [tau]{sub B} = 1.577 ± 0.032 ± 0.046 ps.

Download or read book Proceedings of the 31st International Conference on High Energy Physics ICHEP 2002 written by S. Bentvelsen and published by Elsevier. This book was released on 2012-12-02 with total page 1004 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first precision measurements on CP violation in the B system are reported. Both the BELLE and the BABAR collaboration presented, among others, results for sin 2ß with much improved accuracy. Results from the Sudbury Neutrino Observatory, SNO, also deserve to be mentioned. The convincing evidence of solar neutrino oscillations had been presented by SNO prior to the conference; a full presentation was given at the conference. An incredibly precise measurement of the anomalous magnetic moment of the muon is reported, a fresh result from the Brookhaven National Laboratory. Apart from these distinct physics highlights, there are also the first results from the new Tevatron run and from the relativistic heavy ion collider RHIC. Theorists write of our ever better understanding of the Standard Model and of what might lie beyond. Risky as it is to highlight only a couple of exciting subjects, it is merely meantto whet the appetite for further reading.