Measurement of $b$ Hadron Lifetimes in Exclusive Decays Containing a $J/\psi$ in $p-̂$ Pbar Collisions at $\sqrt{s}
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Published: 2010
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DOWNLOAD EBOOKThe average b-hadron lifetime has been measured using a high statistics sample of[ital B][r-arrow][ital J]/[psi][Chi] decays recorded with the Collider Detector at Fermilab. We use a sample with an integrated luminosity of[approx] 90[ital pb][sup -1] recorded during the 1994-95 running period. The decay vertices of[approx] 62656 inclusive[ital J]/[psi][r-arrow][mu][sup+][mu][sup -] candidates have been reconstructed using information from a silicon vertex-detector. The measured[ital B]lifetime, which is the average over all b-hadrons produced in[ital p][ital[anti p]] collisions at[radical]s= 1.8 TeV weighted by their branching ratios into[ital J]/[psi], is 1.524[+-] 0.015 ([ital stat])[sup+0.035][sub -0.026] ([ital sys]) ps. The precision of this measurement is significantly improved compared to the inclusive lifetime measurement published previously using[approx] 10[ital pb][sup -1].
Author: Hans Wenzel
Publisher: LAP Lambert Academic Publishing
Published: 2010-11
Total Pages: 136
ISBN-13: 9783843367356
DOWNLOAD EBOOKThis dissertation describes the measurement of the average B hadron lifetime using a high statistics sample of B--> J/psi X decays produced in proton antiproton collisions at a center of mass energy of 1.8 TeV at the Fermilab Tevatron. The integrated luminosity of the sample is 10.1 pb-1 recorded with the Collider Detector at Fermilab (CDF). In this analysis the decay vertex of the decay J/psi -->mu^+ mu^-$ as reconstructed by a silicon vertex detector is used to extract the lifetime from the data. We find the following value for the average b hadron lifetime: [ tau_{B} = 1.46 pm 0.06; (stat.); pm 0.06; (syst.); ps] This is the first measurement of the b-hadron lifetime at a hadron collider. It demonstrates that it is possible to access the large b-quark production cross section in $poverline{p}$ collisions and to achieve high statistics even in modes which have small product branching ratios as in this case: $BR(Brightarrow J/psi X) cdot BR(J/psi rightarrow mu^+ mu^-) = 7.7 times 10^{-4}$.
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Published: 2005
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DOWNLOAD EBOOKDuring the run period from May 1992 to begin of June 1993 the Collider Detector at Fermilab (CDF) has recorded [approx] 21.4 pb[sup [minus]1] of p[anti p] collider data at [radical]s = 1.8 TeV. For this run the detector had been upgraded which significantly enhanced its b-physics capabilities. The upgrades include a high precision Silicon VerteX detector (SVX) which enables CDF to reconstruct the decay vertex and decay length of b-hadrons. In this article the author reports on several measurements of the lifetime of b-flavored hadrons. The determination of the average b-lifetime using inclusive J/[psi]'s, the measurement of the B[sup [+-]] and B[sup 0] lifetimes by reconstructing exclusive final states including a J/[psi] or [psi](2S) and a measurement of the B[sub s][sup 0] meson lifetime exploiting the decay: B[sub s] [yields] l[nu]D[sub s][sup +] [yields] l[nu][phi][pi][sup +] [yields] l[nu]K[sup +]K[sup [minus]][pi][sup +].
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Published: 1993
Total Pages: 8
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DOWNLOAD EBOOKBottom hadron lifetime measurements have been performed using B → J/[psi] → [mu]+[mu]−X dacays recorded with the collider Detector at Fermilab (CDF) during the first half of the 1992--1993 Tevatron collider run. These decays have been reconstructed in a silicon vertex detector. Using 5344 ± 73 inclusive J/[psi] events, the average lifetime of all bottom hadrons produced in 1.8 TeV p{bar p} collisions and decaying into a J/[psi] events, the average lifetime of all bottom hadrons produced in 1.8 TeV p{bar p} collisions and decaying into a J/[psi] is found to be 1.46 ± 0.06(stat) ±0.06(sys)ps. The charged and neutral B meson lifetimes have been measured separately using 75 ±10 (charged) and 61±9 (neutral) fully reconstructed decays; preliminary results are [tau]{sup ±} = 1.63 ± 0.21(stat) ± 0.16(sys) ± 0. 10(sys) ps, yielding a lifetime ratio of [tau]{sup ±}/[tau]° = 1.06{plus_minus} 0.20(stat){plus_minus}0.12(sys).
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Published: 2005
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Published: 1993
Total Pages: 131
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Published: 2012
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DOWNLOAD EBOOKWe measure the?{sub b}° lifetime in the fully reconstructed decay?{sub b}° → J/??° using 10.4 fb−1 of p{bar p} collisions collected with the D0 detector at √s = 1.96 TeV. The lifetime of the topologically similar decay channel B° → J/? K{sub S}° is also measured. We obtain? (?{sub b}°) = 1.303 ± 0.075 (stat.) ± 0.035 (syst.) ps and? (B°) = 1.508 ± 0.025 (stat.) ± 0.043 (syst.) ps. Using these measurements, we determine the lifetime ratio of? (?{sub b}°)/? (B°) = 0.864 ± 0.052 (stat.) ± 0.033 (syst.).
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Published: 2011
Total Pages: 5
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DOWNLOAD EBOOKA measurement of b-hadron lifetimes in the fully reconstructed decay modes B 2!J/[psi]K+, B° 2!J/[psi]K*°, B° 2!J/[psi]K{sub S}°, and [Lambda]{sub b}° 2!J/[psi] [Lambda]° is reported using data corresponding to an integrated luminosity of 4.3 fb−1, collected by the CDF II detector at the Fermilab Tevatron. The measured values are [tau](B+) = 1.639 ± 0.009(stat) ± 0.009(syst) ps, [tau](B°) = 1.507 ± 0.010(stat) ± 0.008(syst) ps and [tau]([Lambda]{sub b}°) = 1.537 ± 0.045(stat) ± 0.014(syst) ps. The lifetime ratios are [tau](B+)/[tau](B°) - 1.088 ± 0.009(stat) ± 0.004(syst) and [tau]([Lambda]{sub b}°)/[tau](B°) = 1.020 ± 0.030(stat) ± 0.008(syst). These are the most precise measurements of these quantities from a single experiment. Observation is also reported for a structure near the J/[psi][phi] threshold, in B+ to J/[psi][phi]K+ decays with an integrated luminosity of 6.0 fb−1 and a statistical significance of 5 standard deviations. There are 19 ± 6 events observed for this structure at a mass of 4143.4{sub -3.0}{sup +2.9} ± 0.6 MeV/c2 and a width of 15.3{sub -6.1}{sup +10.4} ± 2.5 MeV/c2.
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Published: 2010
Total Pages: 4
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DOWNLOAD EBOOKThe Tevatron provides 1.96 TeV p{bar p} collisions and allows for collection of rich b-hadron samples to the two experiments CDF and D0. The study of heavy flavor properties represents a fruitful opportunity to investigate the flavor sector of the Standard Model (SM) and to look for hints of New Physics (NP). Here we report the first measurement of polarization amplitudes in B{sub s}° charmless decays, world leading results on b-hadron lifetimes, and measurements of several other properties of b-hadrons.