First Measurement of the B-jet Cross Section in Events with a W Boson in P Anti-p Collisions at S**1/2


Book Description

The cross section for jets from b quarks produced simultaneously with a W boson has been measured in p{bar p} collision data from 1.9 fb−1 of integrated luminosity recorded by the CDF II detector at the Tevatron. Jets consistent with the decay of long-lived hadrons are selected by identifying a displaced decay vertex. The invariant mass of the charged particle tracks associated with the vertex is sensitive to the flavor of the decaying hadron and is used to determine the fraction of jets from b-quark production. We measure a b-jet cross section of 2.74 ± 0.27(stat.) ± 0.42(syst.) pb in association with one flavor of leptonic W boson decay over a limited kinematic phase space.




First Measurement of the B-jet Cross Section in Events with a W Boson in P Anti-p Collisions at S**ư


Book Description

The cross section for jets from b quarks produced simultaneously with a W boson has been measured in p{bar p} collision data from 1.9 fb−1 of integrated luminosity recorded by the CDF II detector at the Tevatron. Jets consistent with the decay of long-lived hadrons are selected by identifying a displaced decay vertex. The invariant mass of the charged particle tracks associated with the vertex is sensitive to the flavor of the decaying hadron and is used to determine the fraction of jets from b-quark production. We measure a b-jet cross section of 2.74 ± 0.27(stat.) ± 0.42(syst.) pb in association with one flavor of leptonic W boson decay over a limited kinematic phase space.







Measurement of Cross Sections for B Jet Production in Events with a Z Boson in P-anti-p Collisions at S**1/2


Book Description

A measurement of the b jet production cross section is presented for events containing a Z boson produced in p{bar p} collisions at √s = 1.96 TeV, using data corresponding to an integrated luminosity of 2 fb−1 collected by the CDF II detector at the Tevatron. Z bosons are selected in the electron and muon decay modes. Jets are considered with transverse energy E{sub T} > 20 GeV and pseudorapidity.




Measurement of $Z/\gamma^* + B$-jet Production Cross Section in $p\bar{p}$ Collisions at $\sqrt{s}


Book Description

Processes at hadron colliders, such as the production of jets, are described by the Quantum Chromodynamics theory (QCD). Precise descriptions of processes involving jets in association with a vector boson have nowadays large relevance as they represent irreducible background to other Standard Model (SM) processes and searches for new physics. The experimental study and understanding of the b-jet production in association with a Z boson are crucial for many reasons. For one side, it is the most important background for a light Higgs boson decaying into a bottom-antibottom quark pair and produced in the ZH mode. This is one of the most promising channels for the Higgs search at Tevatron in particular since the latest results have excluded the high mass region (MH> 127 GeV/c2). For another side the signature of b-jets and a Z boson is also background to new physics searches, such as supersymmetry, where a large coupling of the Higgs boson to bottom quarks is allowed. The produ ction cross section measurement of b-jets in events with a Z boson has already been performed at hadron colliders, at the Tevatron by CDF and D0 experiments and are now pursued at the LHC by ATLAS and CMS. In particular the CDF measurement was performed with only 2 fb-1 and was limited by the statistical uncertainty. This PhD thesis presents a new measurement of the $Z/\gamma^* + b$-jet production cross section using the complete dataset collected by CDF during the Run II. $Z/\gamma^*$ bosons are selected in the electron and muon decay modes and are required to have 66




Measurement of the W+- + B Anti-b Cross-section in 695-pb-1 of P Anti-p Collisions at CDF II.


Book Description

W{sup ±} + b{bar b} events contain the associated production of a W{sup ±} boson, a pair of bottom quarks (b{bar b}), and any number of additional partons. This process is of much importance at hadron collider experiments due to its role as a background source in searches for Standard Model Higgs boson and single top-quark production. In this thesis the results are presented for a measurement of the b-jet cross-section in W{sup ±} + b{bar b} events containing 1 or 2 jets in 695 pb−1 of √s =1.96 TeV p{bar p} collisions at the CDF experiment. This is the first measurement of the cross-section of W{sup {+-}} b{bar b} performed in any experiment. The cross-section is defined to be proportional to the number of b-jets from W{sup {+-}} b{bar b} events with one or two jets, and a leptonically decaying W{sup {+-}} with decay products passing kinematics cuts (p{sub T}(l{sup {+-}}) ≥ 20.0 GeV,




Measurement of the W± + B$\bar{b}$ Cross-section in 695-pb-1 of P$\bar{p}$ Collisions at CDF II.


Book Description

W± + b$ar{b}$ events contain the associated production of a W± boson, a pair of bottom quarks (b$ar{b}$), and any number of additional partons. This process is of much importance at hadron collider experiments due to its role as a background source in searches for Standard Model Higgs boson and single top-quark production. In this thesis the results are presented for a measurement of the b-jet cross-section in W± + b$ar{b}$ events containing 1 or 2 jets in 695 pb-1 of √s =1.96 TeV p$ar{p}$ collisions at the CDF experiment. This is the first measurement of the cross-section of W± b$ar{b}$ performed in any experiment. The cross-section is defined to be proportional to the number of b-jets from W± b$ar{b}$ events with one or two jets, and a leptonically decaying W± with decay products passing kinematics cuts (pT(l±) ≥ 20.0 GeV,







Measurement of the Production and Differential Cross Sections of $W{̂+}W{̂-}$ Bosons in Association with Jets in $p\bar{p}$ Collisions at $\sqrt{s}


Book Description

In this study, we present a measurement of the W-boson-pair production cross section in pp¯ collisions at 1.96 TeV center-of-mass energy and the first measurement of the differential cross section as a function of jet multiplicity and leading-jet energy. The W+W– cross section is measured in the final state comprising two charged leptons and neutrinos, where either charged lepton can be an electron or a muon. Using data collected by the CDF experiment corresponding to 9.7 fb–1 of integrated luminosity, a total of 3027 collision events consistent with W+W– production are observed with an estimated background contribution of 1790±190 events. The measured total cross section is ?(pp¯→W+W–) = 14.0 ± 0.6(stat)+1.2–1.0 (syst)±0.8 (lumi) pb, consistent with the standard model prediction.




Measurement of the Production Cross Section of the W Boson in Association with Two B Jets in Pp Collisions at $\sqrt{s}$


Book Description

The production cross section of a W boson in association with two b jets is measured using a sample of proton-proton collisions at $ \sqrt{s} = $ 8 TeV collected by the CMS experiment at the CERN LHC. The data sample corresponds to an integrated luminosity of 19.8 fb$^{-1}$. The W bosons are reconstructed via their leptonic decays, $ \mathrm{ W }\to\ell\nu $, where $\ell=\mu$ or $\mathrm{ e }$. The fiducial region studied contains exactly one lepton with transverse momentum $ p_{\mathrm{T}}^{\ell}> $ 30 GeV and pseudorapidity $