A Measurement of the Branching Ratio of the Z Boson to Bottom Quarks Using Precision Tracking

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ISBN 13 :
Total Pages : 332 pages
Book Rating : 4.F/5 ( download)

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Book Synopsis A Measurement of the Branching Ratio of the Z Boson to Bottom Quarks Using Precision Tracking by : Robert Gibbs Jacobsen

Download or read book A Measurement of the Branching Ratio of the Z Boson to Bottom Quarks Using Precision Tracking written by Robert Gibbs Jacobsen and published by . This book was released on 1991 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Measurement of the Z-boson Branching Fraction Into Hadrons Containing Bottom Quarks

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ISBN 13 :
Total Pages : 106 pages
Book Rating : 4.:/5 (893 download)

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Book Synopsis Measurement of the Z-boson Branching Fraction Into Hadrons Containing Bottom Quarks by :

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.

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

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ISBN 13 :
Total Pages : 606 pages
Book Rating : 4.F/5 ( download)

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Book Synopsis 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 by : Dale Steven Koetke

Download or read book 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 written by Dale Steven Koetke and published by . This book was released on 1992 with total page 606 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Measurement of the Z-Boson Branching Fraction Into Hadrons Containing Bottom Quarks

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ISBN 13 :
Total Pages : 286 pages
Book Rating : 4.:/5 (33 download)

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Book Synopsis Measurement of the Z-Boson Branching Fraction Into Hadrons Containing Bottom Quarks by : J. Frederic Kral

Download or read book Measurement of the Z-Boson Branching Fraction Into Hadrons Containing Bottom Quarks written by J. Frederic Kral and published by . This book was released on 1990 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Energy Research Abstracts

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ISBN 13 :
Total Pages : 678 pages
Book Rating : 4.3/5 (243 download)

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Book Synopsis Energy Research Abstracts by :

Download or read book Energy Research Abstracts written by and published by . This book was released on 1991 with total page 678 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Measurement of the Branching Ratio of the Z0 Into Heavy Quarks

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (871 download)

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Book Synopsis Measurement of the Branching Ratio of the Z0 Into Heavy Quarks by :

Download or read book Measurement of the Branching Ratio of the Z0 Into Heavy Quarks written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Measurements of the Top Quark Pair Production Cross Section and Branching Ratio to a W-boson and Bottom Quark Using the Semi-leptonic and Dilepton Final States with the ATLAS Detector at the LHC

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ISBN 13 : 9781267906960
Total Pages : 241 pages
Book Rating : 4.9/5 (69 download)

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Book Synopsis Measurements of the Top Quark Pair Production Cross Section and Branching Ratio to a W-boson and Bottom Quark Using the Semi-leptonic and Dilepton Final States with the ATLAS Detector at the LHC by : Robert E. Calkins

Download or read book Measurements of the Top Quark Pair Production Cross Section and Branching Ratio to a W-boson and Bottom Quark Using the Semi-leptonic and Dilepton Final States with the ATLAS Detector at the LHC written by Robert E. Calkins and published by . This book was released on 2012 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract : In the Standard Model, the top quark plays a unique role as the heaviest known fundamental particle and as a quark that decays before it is able to hadronize. Top quarks are expected to decay to a W-boson and a b-quark nearly 100% of the time. If the branching ratio of t → Wb is lower than one, the distribution of the number of b-tagged jets will shift to lower multiplicities. A simultaneous likelihood fit to the number of b-tagged jets distributions in the lepton+jets and dilepton channels is performed on 4.7 fb−1 of data collected by the ATLAS detector to extract both the branching ratio and the tt ̄ cross section. The branching ratio of t → Wb, R, is measured to be 1.06±0.11, which is consistent with the Standard Model value. This is the first measurement of the t → Wb branching ratio performed with the ATLAS detector using both the lepton+jets and dilepton channels at the LHC. The tt ̄ cross section is measured to be [special characters omitted] pb, which agrees with NNLO predictions.

A Measurement of the Z° Hadronic Branching Fraction to Bottom Quarks and the Charged Multiplicity of Bottom Quark Events Using Precision Vertex Detectors at E{sub Cm}

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ISBN 13 :
Total Pages : 296 pages
Book Rating : 4.:/5 (873 download)

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Book Synopsis A Measurement of the Z° Hadronic Branching Fraction to Bottom Quarks and the Charged Multiplicity of Bottom Quark Events Using Precision Vertex Detectors at E{sub Cm} by :

Download or read book A Measurement of the Z° Hadronic Branching Fraction to Bottom Quarks and the Charged Multiplicity of Bottom Quark Events Using Precision Vertex Detectors at E{sub Cm} written by and published by . This book was released on 1992 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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, [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 is {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.

A Measurement of the Z Sup 0 Hadronic Branching Fraction to Bottom Quarks and the Charged Multiplicity of Bottom Quark Events Using Precision Vertex Detectors at E Sub Cm

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ISBN 13 :
Total Pages : 296 pages
Book Rating : 4.:/5 (16 download)

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Book Synopsis A Measurement of the Z Sup 0 Hadronic Branching Fraction to Bottom Quarks and the Charged Multiplicity of Bottom Quark Events Using Precision Vertex Detectors at E Sub Cm by :

Download or read book A Measurement of the Z Sup 0 Hadronic Branching Fraction to Bottom Quarks and the Charged Multiplicity of Bottom Quark Events Using Precision Vertex Detectors at E Sub Cm written by and published by . This book was released on 1992 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

A Measurement of Bottom Quark Production in Z Boson Hadronic Decays

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ISBN 13 :
Total Pages : 13 pages
Book Rating : 4.:/5 (316 download)

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Book Synopsis A Measurement of Bottom Quark Production in Z Boson Hadronic Decays by : J. Coller

Download or read book A Measurement of Bottom Quark Production in Z Boson Hadronic Decays written by J. Coller and published by . This book was released on 2003 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

A Measurement of Bottom Quark Production in Z Boson Hadronic Decays

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ISBN 13 :
Total Pages : 194 pages
Book Rating : 4.:/5 (51 download)

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Book Synopsis A Measurement of Bottom Quark Production in Z Boson Hadronic Decays by : John A. Coller

Download or read book A Measurement of Bottom Quark Production in Z Boson Hadronic Decays written by John A. Coller and published by . This book was released on 2000 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:

The Vancouver Meeting, Particles & Fields '91, Vancouver, B.C., Canada, 18-22 August, 1991

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Publisher : World Scientific Publishing Company
ISBN 13 :
Total Pages : 640 pages
Book Rating : 4.:/5 ( download)

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Book Synopsis The Vancouver Meeting, Particles & Fields '91, Vancouver, B.C., Canada, 18-22 August, 1991 by : American Physical Society. Division of Particles and Fields. Meeting

Download or read book The Vancouver Meeting, Particles & Fields '91, Vancouver, B.C., Canada, 18-22 August, 1991 written by American Physical Society. Division of Particles and Fields. Meeting and published by World Scientific Publishing Company. This book was released on 1992 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Search for the Neutral Current Top Quark Decay T--]Zc Using Ratio of Z-Boson + 4 Jets to W-Boson + 4 Jets Production

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (873 download)

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Book Synopsis Search for the Neutral Current Top Quark Decay T--]Zc Using Ratio of Z-Boson + 4 Jets to W-Boson + 4 Jets Production by :

Download or read book Search for the Neutral Current Top Quark Decay T--]Zc Using Ratio of Z-Boson + 4 Jets to W-Boson + 4 Jets Production written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We have used the Collider Detector at Fermilab (CDF II) to search for the flavor-changing neutral-current (FCNC) top quark decay t → Zc using a technique employing ratios of W and Z production, measured in p{bar p} data corresponding to an integrated luminosity of 1.52 fb−1. The analysis uses a comparison of two decay chains, p{bar p} → t{bar t} → WbWb → l[nu]bjjb and p{bar p} → t{bar t} → ZcWb → llcjjb, to cancel systematic uncertainties in acceptance, efficiency, and luminosity. We validate the modeling of acceptance and efficiency for lepton identification over the multi-year dataset using another ratio of W and Z production, in this case the observed ratio of inclusive production of W to Z bosons. To improve the discrimination against standard model backgrounds to top quark decays, we calculate the top quark mass for each event with two leptons and four jets assuming it is a t{bar t} event with one of the top quarks decaying to Zc. For additional background discrimination we require at least one jet to be identified as originating from a b-quark. No significant signal is found and we set an upper limit on the FCNC branching ratio Br(t → Zc) using a likelihood constructed from the llcjjb top quark mass distribution and the number of l[nu]bjjb events. Limits are set as a function of the helicity of the Z boson produced in the FCNC decay. For 100% longitudinally polarized Z bosons we find limits of 8.3% and 9.3% (95% C.L.) depending on the assumptions regarding the theoretical top quark pair production cross-section.

A Limit on the Branching Ratio of the Flavor-Changing Top Quark Decay T--]Zc

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ISBN 13 :
Total Pages : 119 pages
Book Rating : 4.:/5 (873 download)

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Book Synopsis A Limit on the Branching Ratio of the Flavor-Changing Top Quark Decay T--]Zc by :

Download or read book A Limit on the Branching Ratio of the Flavor-Changing Top Quark Decay T--]Zc written by and published by . This book was released on 2009 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have used the Collider Detector at Fermilab (CDF-II) to set upper limits on the branching ratio of the flavor-changing neutral-current (FCNC) top quark decay t 2!Zc using a technique employing ratios of W and Z production, measured in 1.52 fb−1 of p{bar p} data. The analysis uses a comparison of two decay chains, p{bar p} 2!t{bar t} 2!WbWb 2!l[nu]bjjb and p{bar p} 2!t{bar t} ZcWb 2!ll− cjjb, to cancel systematic uncertainties in acceptance, efficiency, and luminosity. We validate the MC modeling of acceptance and efficiency for lepton identification over the multi-year dataset also using a ratio of W and Z production, in this case the observed ratio of inclusive production of W to Z-bosons, a technique that will be essential for precision comparisons with the standard model at the LHC. We introduce several methods of determining backgrounds to the W and Z samples. To improve the discrimination against SM backgrounds to top quark decays, we calculate the top mass for each event with two leptons and four jets assuming it is a t{bar t} event with one of the top quarks decaying to Zc. The upper limit on the Br(t 2!Zc) is estimated from a likelihood constructed with the ll− cjjb top mass distribution and the number of l[nu]bjjb events. Limits are set as a function of the helicity of the Z-boson produced in the FCNC decay. For 100%-longitudinally-polarized Z-bosons we find a limit of 8.3% (95% C.L.).

A Measurement of the Z Branching Fraction to Bottom Quarks

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ISBN 13 :
Total Pages : 202 pages
Book Rating : 4.:/5 (394 download)

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Book Synopsis A Measurement of the Z Branching Fraction to Bottom Quarks by : Joel Goldstein

Download or read book A Measurement of the Z Branching Fraction to Bottom Quarks written by Joel Goldstein and published by . This book was released on 1998 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Measurement of Bottom Quark Pair Production, in Association with Z Bosons and Top Quarks, with the ATLAS Detector

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ISBN 13 :
Total Pages : 223 pages
Book Rating : 4.:/5 (115 download)

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Book Synopsis Measurement of Bottom Quark Pair Production, in Association with Z Bosons and Top Quarks, with the ATLAS Detector by : Stewart Swift (Ph. D. in physics)

Download or read book Measurement of Bottom Quark Pair Production, in Association with Z Bosons and Top Quarks, with the ATLAS Detector written by Stewart Swift (Ph. D. in physics) and published by . This book was released on 2019 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt:

The determination of the branching ratios of the Z Boson into heavy quarks using neural networks

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ISBN 13 :
Total Pages : 100 pages
Book Rating : 4.:/5 (661 download)

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Book Synopsis The determination of the branching ratios of the Z Boson into heavy quarks using neural networks by : Nicolo de Groot

Download or read book The determination of the branching ratios of the Z Boson into heavy quarks using neural networks written by Nicolo de Groot and published by . This book was released on 1993 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: