Measurement of the Z-boson Branching Fraction Into Hadrons Containing Bottom Quarks PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Measurement of the Z-boson Branching Fraction Into Hadrons Containing Bottom Quarks PDF full book. Access full book title Measurement of the Z-boson Branching Fraction Into Hadrons Containing Bottom Quarks by . Download full books in PDF and EPUB format.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 106
Get Book Here
Book Description
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.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 106
Get Book Here
Book Description
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.
Author: J. Frederic Kral
Publisher:
ISBN:
Category :
Languages : en
Pages : 286
Get Book Here
Book Description
Author: Robert Gibbs Jacobsen
Publisher:
ISBN:
Category : Quarks
Languages : en
Pages : 332
Get Book Here
Book Description
Author: J. Coller
Publisher:
ISBN:
Category :
Languages : en
Pages : 13
Get Book Here
Book Description
A precise measurement of R{sub b}, the fraction of hadronic decays of the Z{sup 0} boson into bottom quark pairs, will test the Standard Model of particle physics. By measuring R{sub b}, the coupling between the Z{sup 0} boson and bottom quarks can be investigated. The strength of this coupling is sensitive to the top quark mass and to physics which lies outside the Standard Model. This thesis presents a measurement of R{sub b} made at the Stanford Linear Accelerator Center with the SLD experiment. Approximately 196,000 hadronic events are used in the measurement. The data set was obtained during the 1997-98 SLD physics run. The selection of B hadrons for identifying Z{sup 0} {yields} b{bar b} events is based on the invariant mass of topologically reconstructed vertices separated from the primary vertex for the event. This reconstruction method identifies B hadrons with a high efficiency (49.9%) and high purity (98.0%). Each candidate Z{sup 0} {yields} b{bar b} event is split into two separate hemispheres which are analyzed independently. The efficiency for tagging B hadrons is extracted from the data, reducing the dependence on the Monte Carlo simulation for B hadron and b quark systematic errors. A measured result of R{sub b} = 0.2185 {+-} 0.0013{sub (stat)} {+-} 0.0022{sub (syst.)} is reported. This value is consistent within measurement errors with the Standard Model prediction of 0.2158. The significant of this measurement is discussed.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 296
Get Book Here
Book Description
Using the precision vertex detectors of the Mark 2 at the SLC, an impact parameter tag was developed to select a sample of hadronic Z° decays enriched in its fraction of bottom quark events. The nominal tagging method requires that there be at least three tracks whose impact parameters are inconsistent with the track having originated at the electron-position interaction point. A tagging efficiency for b{bar b} events of 50% with a enriched sample purity of 85% was achieved. This impact parameter tag was used to measure the fraction hadronic Z° decays which produce b{bar b} events, F{sub b}. It is found that F{sub b} = 0.232{sub -0.045}{sup +0.053} (stat) {sub -0.021}{sup +0.025} (syst). This result is consistent with those found using other tagging methods as well as the Standard Model prediction of 0.217. The b{bar b}-enriched event sample was also used to measure the difference between the average charged multiplicity of b{bar b} events and that of all hadronic Z° decays,?{bar n}{sub b} = 2.11 {plus minus} 1.82(stat) {plus minus} 0.57(syst). Using previous measurements of the total hadronic charged multiplicity, the corresponding total multiplicity for b{bar b} events is {bar n}{sub b}=23.05 {plus minus} 1.82 (stat) {plus minus} 0.60 (syst). Subtracting the contribution to the multiplicity from B hadron decays yields the multiplicity of the b{bar b} non-leading system, {bar n}{sub nl} = 12.04 {plus minus} 1.82 (stat) {plus minus} 0.63(syst). Comparing this non-leading multiplicity to the total hadronic multiplicity data at lower energy supports the hypothesis that the non-leading particle production is independent of the flavor of the initial quarks.
Author: John A. Coller
Publisher:
ISBN:
Category : Quarks
Languages : en
Pages : 194
Get Book Here
Book Description
Author: Dale Steven Koetke
Publisher:
ISBN:
Category : Hadron interactions
Languages : en
Pages : 606
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author: Joel Goldstein
Publisher:
ISBN:
Category : Collisions (Nuclear physics)
Languages : en
Pages : 202
Get Book Here
Book Description
Author: Daniel Edward Klem
Publisher:
ISBN:
Category :
Languages : en
Pages : 304
Get Book Here
Book Description
