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Title: A measurement of the Z 0 hadronic branching fraction to bottom quarks and the charged multiplicity of bottom quark events using precision vertex detectors at E cm = 91 GeV

Abstract

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 b. It is found that F b = 0.232$$+0.053\atop{-0.045}$$ (stat) $$+0.025\atop{-0.021}$$ (syst). This result is consistent with those found using other tagging methods as well as the Standard Model prediction of 0.217. The b 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, δ$$\bar{n}$$ b = 2.11 ± 1.82(stat) ± 0.57(syst). Using previous measurements of the total hadronic charged multiplicity, the corresponding total multiplicity for b$$\bar{b}$$ events is $$\bar{n}$$ b=23.05 ± 1.82 (stat) ± 0.60 (syst). Subtracting the contribution to the multiplicity from B hadron decays yields the multiplicity of the b$$\bar{b}$$ non-leading system, $$\bar{n}$$$\bar{nl}$$ = 12.04 ± 1.82 (stat) ± 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.

Authors:
 [1]
+ Show Author Affiliations
  1. Stanford Univ., CA (United States)
Publication Date:
Research Org.:
Stanford Linear Accelerator Center, Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
10164831
Report Number(s):
SLAC-396
ON: DE92018236
DOE Contract Number:
AC03-76SF00515
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: TH: Thesis (Ph.D.); PBD: Jun 1992
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Z NEUTRAL BOSONS; HADRONIC PARTICLE DECAY; BRANCHING RATIO; BEAUTY PARTICLES; MULTIPLICITY; EXPERIMENTAL DATA; STANFORD LINEAR COLLIDER DETECTOR; STANDARD MODEL; MONTE CARLO METHOD; PERFORMANCE; QUARKS; 662380; DECAYS OF INTERMEDIATE BOSONS

Citation Formats

Koetke, Dale Steven. A measurement of the Z0 hadronic branching fraction to bottom quarks and the charged multiplicity of bottom quark events using precision vertex detectors at Ecm = 91 GeV. United States: N. p., 1992. Web. doi:10.2172/10164831.
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Koetke, Dale Steven. A measurement of the Z0 hadronic branching fraction to bottom quarks and the charged multiplicity of bottom quark events using precision vertex detectors at Ecm = 91 GeV. United States. doi:10.2172/10164831.
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Koetke, Dale Steven. Mon . "A measurement of the Z0 hadronic branching fraction to bottom quarks and the charged multiplicity of bottom quark events using precision vertex detectors at Ecm = 91 GeV". United States. doi:10.2172/10164831. https://www.osti.gov/servlets/purl/10164831.
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@article{osti_10164831,
title = {A measurement of the Z0 hadronic branching fraction to bottom quarks and the charged multiplicity of bottom quark events using precision vertex detectors at Ecm = 91 GeV},
author = {Koetke, Dale Steven},
abstractNote = {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, Fb. It is found that Fb = 0.232$+0.053\atop{-0.045}$ (stat) $+0.025\atop{-0.021}$ (syst). This result is consistent with those found using other tagging methods as well as the Standard Model prediction of 0.217. The bb-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, δ$\bar{n}$b = 2.11 ± 1.82(stat) ± 0.57(syst). Using previous measurements of the total hadronic charged multiplicity, the corresponding total multiplicity for b$\bar{b}$ events is $\bar{n}$b=23.05 ± 1.82 (stat) ± 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}$$\bar{nl}$ = 12.04 ± 1.82 (stat) ± 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.},
doi = {10.2172/10164831},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jun 01 00:00:00 EDT 1992},
month = {Mon Jun 01 00:00:00 EDT 1992}
}
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Thesis/Dissertation:
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DOI:  10.2172/10164831
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  • Using the precision vertex detectors of the Mark II at the SLC, an impact parameter tag was developed to select a sample of hadronic Z[sup 0] 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 an enriched sample purity of 85% was achieved. This impact parameter tag was used to measure the fraction hadronic Z[sup 0] decays which produce b[bar b] events, F[submore » b]. It is found that F[sub b] = 0.232[sub [minus]0.045][sup +0.053](stat) [sub [minus]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[sup 0] decays, [delta][bar n][sub b] = 2.11 [+-] 1.82 (stat) [+-] 0.57 (syst). Using previous measurements of the total hadronic charged multiplicity, the corresponding total multiplicity for b[bar b] events in [bar n][sub b] = 23.05[+-]1.82 (stat) [+-] 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 [+-] 1.82 (stat) [+-] 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. This also yields a determination of the average energy fraction of bottom hadrons in Z[sup 0] decays of [l angle]x[sub E][r angle][sub b] = 0.619[sub [minus].107[sup +.096]] (stat) [sub [minus].045[sup +.043]] (syst).« less

  • 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{degree} 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{degree} decays which produce b{bar b} events, F{sub b}. Itmore » is found that F{sub b} = 0.232{sub {minus}0.045}{sup +0.053} (stat) {sub {minus}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{degree} decays, {delta}{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.« less

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