Author: Daniel Edward Klem
Publisher:
ISBN:
Category :
Languages : en
Pages : 304
Book Description
A Measurement of the Average Lifetime of Hadrons Containing Bottom Quarks
Measurement of the Average Lifetime of Hadrons Containing Bottom Quarks
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
This thesis reports a measurement of the average lifetime of hadrons containing bottom quarks. It is based on data taken with the DELCO detector at the PEP ee− storage ring at a center of mass energy of 29 GeV. The decays of hadrons containing bottom quarks are tagged in hadronic events by the presence of electrons with a large component of momentum transverse to the event axis. Such electrons are identified in the DELCO detector by an atmospheric pressure Cherenkov counter assisted by a lead/scintillator electromagnetic shower counter. The lifetime measured is 1.17 psec, consistent with previous measurements. This measurement, in conjunction with a limit on the non-charm branching ratio in b-decay obtained by other experiments, can be used to constrain the magnitude of the V/sub cb/ element of the Kobayashi-Maskawa matrix to the range 0.042 (+0.005 or -0.004 (stat.), +0.004 or -0.002 (sys.)), where the errors reflect the uncertainty on tau/sub b/ only and not the uncertainties in the calculations which relate the b-lifetime and the element of the Kobayashi-Maskawa matrix.
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
This thesis reports a measurement of the average lifetime of hadrons containing bottom quarks. It is based on data taken with the DELCO detector at the PEP ee− storage ring at a center of mass energy of 29 GeV. The decays of hadrons containing bottom quarks are tagged in hadronic events by the presence of electrons with a large component of momentum transverse to the event axis. Such electrons are identified in the DELCO detector by an atmospheric pressure Cherenkov counter assisted by a lead/scintillator electromagnetic shower counter. The lifetime measured is 1.17 psec, consistent with previous measurements. This measurement, in conjunction with a limit on the non-charm branching ratio in b-decay obtained by other experiments, can be used to constrain the magnitude of the V/sub cb/ element of the Kobayashi-Maskawa matrix to the range 0.042 (+0.005 or -0.004 (stat.), +0.004 or -0.002 (sys.)), where the errors reflect the uncertainty on tau/sub b/ only and not the uncertainties in the calculations which relate the b-lifetime and the element of the Kobayashi-Maskawa matrix.
Spectroscopy and Lifetime of Bottom and Charm Hadrons
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
There are several motivations for studying masses and lifetimes of the hadrons containing a heavy quark, either the bottom or the charm quark. First, the mass and the lifetime are fundamental properties of an elementary particle. Second, the spectroscopy of hadrons gives insights into the QCD potential between quarks. In particular, a symmetry exists for heavy hadrons when the heavy quark mass is taken to be infinite, providing a powerful tool to predict and understand properties of those heavy hadrons. Third, studies of the lifetimes of heavy hadrons probe their decay mechanisms. A measurement of the lifetime, or the total decay width, is necessary when the authors extract magnitudes of elements of the Kobayashi-Maskawa matrix. Again, in the limit of an infinite heavy quark mass things become simple and decay of a heavy hadron should be the decay of the heavy quark Q. This leads to a prediction that all hadrons containing the heavy quark Q should have the same lifetime, that of the quark Q. This is far from reality in the case of charm hadrons, where the D meson lifetime is about 2.5 times longer than the D° meson lifetime. Perhaps the charm quark is not heavy enough. The simple quark decay picture should be a better approximation for the bottom hadrons because of the larger b quark mass. On the experimental side, the measurements and knowledge of the heavy hadrons (in particular bottom hadrons) have significantly improved over the last decade, thanks to high statistics data accumulated by various experiments. The authors shall review recent developments in these studies in the remainder of this manuscript.
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
There are several motivations for studying masses and lifetimes of the hadrons containing a heavy quark, either the bottom or the charm quark. First, the mass and the lifetime are fundamental properties of an elementary particle. Second, the spectroscopy of hadrons gives insights into the QCD potential between quarks. In particular, a symmetry exists for heavy hadrons when the heavy quark mass is taken to be infinite, providing a powerful tool to predict and understand properties of those heavy hadrons. Third, studies of the lifetimes of heavy hadrons probe their decay mechanisms. A measurement of the lifetime, or the total decay width, is necessary when the authors extract magnitudes of elements of the Kobayashi-Maskawa matrix. Again, in the limit of an infinite heavy quark mass things become simple and decay of a heavy hadron should be the decay of the heavy quark Q. This leads to a prediction that all hadrons containing the heavy quark Q should have the same lifetime, that of the quark Q. This is far from reality in the case of charm hadrons, where the D meson lifetime is about 2.5 times longer than the D° meson lifetime. Perhaps the charm quark is not heavy enough. The simple quark decay picture should be a better approximation for the bottom hadrons because of the larger b quark mass. On the experimental side, the measurements and knowledge of the heavy hadrons (in particular bottom hadrons) have significantly improved over the last decade, thanks to high statistics data accumulated by various experiments. The authors shall review recent developments in these studies in the remainder of this manuscript.
Scientific and Technical Aerospace Reports
Measurement of the B Hadron Lifetime
Author: Renʹe Ashwin Ong
Publisher:
ISBN:
Category : Hadrons
Languages : en
Pages : 266
Book Description
Publisher:
ISBN:
Category : Hadrons
Languages : en
Pages : 266
Book Description
Energy Research Abstracts
Recent Measurements of the Average Lifetime of Hadrons Containing B-quarks from PEP Experiments at SLAC (Stanford Linear Accelerator Center).
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Recent precise results from several experiments have confirmed the early evidence that the lifetime of hadrons containing B-quarks is rather long, implying that the third generation of quarks is more decoupled from the first two than the second is from the first. The average of the measurements performed by the experiments at PEP is 1.08 +- 0.13 ps.
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Recent precise results from several experiments have confirmed the early evidence that the lifetime of hadrons containing B-quarks is rather long, implying that the third generation of quarks is more decoupled from the first two than the second is from the first. The average of the measurements performed by the experiments at PEP is 1.08 +- 0.13 ps.
Determination of the Average Lifetime of Bottom Hadrons from Vertex Reconstruction
Author: Allen Christopher Caldwell
Publisher:
ISBN:
Category :
Languages : en
Pages : 414
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 414
Book Description
Symmetry And Spin In Standard Model - Proceedings Of The Seventh Lake Louise Winter Institute
Author: Faqir C Khanna
Publisher: World Scientific
ISBN: 9814554685
Category :
Languages : en
Pages : 450
Book Description
The subject of this Institute is the importance of Spin and Symmetry measurements in probing the Standard Model and QCD, polarization in lepton-quark interactions, nucleon spin structure functions, spin effects in high energy hadronic interactions, and electromagnetic spin physics at medium energies.The pedagogical nature of the invited talks makes this book suitable for senior graduate students and subatomic physicists in general, while the specialist talks make the volume useful to practitioners in the field.
Publisher: World Scientific
ISBN: 9814554685
Category :
Languages : en
Pages : 450
Book Description
The subject of this Institute is the importance of Spin and Symmetry measurements in probing the Standard Model and QCD, polarization in lepton-quark interactions, nucleon spin structure functions, spin effects in high energy hadronic interactions, and electromagnetic spin physics at medium energies.The pedagogical nature of the invited talks makes this book suitable for senior graduate students and subatomic physicists in general, while the specialist talks make the volume useful to practitioners in the field.