Measurement of the Top Quark Mass and $p\bar{p}$ -> $t\bar{t}$ Cross Section in the All-Hadronic Mode with the CDFII Detector
Fermilab-Tevatron. Measurement of the top quark mass and TOP TOPBAR pair production cross section... more Fermilab-Tevatron. Measurement of the top quark mass and TOP TOPBAR pair production cross section in PBAR P collisions at a centre of mass energy of 1.96 TeV. Events are selected with six or more jets satisfying a number of kinematical requirements imposed by a neural-network algorithm. At least one jet must be from a b-quark identified as coming from secondary vertex inside the jet. The measured top quark mass of 174.8 +- 2.4 +1.2,-1.0 GeV is based on a likelihood fit of signal and background with the absolute jet energy scale being simultaneously measured. This procedure also derives the cross section reported here. The data sample has an integrated luminosity of 2.9 FB-1.
Top Quark Mass Measurement in the $t \bar{t}$ All Hadronic Channel using a Matrix Element Technique in $p\bar{p}$ Collisions at $\sqrt{s}$ = 1.96-TeV
We present a measurement of the top quark mass in the all-hadronic channel (\tt $\to$ \bb$q_{1}\b... more We present a measurement of the top quark mass in the all-hadronic channel (\tt $\to$ \bb$q_{1}\bar{q_{2}}q_{3}\bar{q_{4}}$) using 943 pb$^{-1}$ of \ppbar collisions at $\sqrt {s} = 1.96$ TeV collected at the CDF II detector at Fermilab (CDF). We apply the standard model production and decay matrix-element (ME) to $\ttbar$ candidate events. We calculate per-event probability densities according to the ME calculation and construct template models of signal and background. The scale of the jet energy is calibrated using additional templates formed with the invariant mass of pairs of jets. These templates form an overall likelihood function that depends on the top quark mass and on the jet energy scale (JES). We estimate both by maximizing this function. Given 72 observed events, we measure a top quark mass of 171.1 $\pm$ 3.7 (stat.+JES) $\pm$ 2.1 (syst.) GeV/$c^{2}$. The combined uncertainty on the top quark mass is 4.3 GeV/$c^{2}$.
Using the full CDF Run II data sample, we report evidence for a new resonance, which we refer to ... more Using the full CDF Run II data sample, we report evidence for a new resonance, which we refer to as B(5970), found simultaneously in the B 0 π + and B + π − mass distributions with a significance of 4.4 standard deviations. We further report the first study of resonances consistent with orbitally excited B + mesons and an updated measurement of the properties of orbitally excited B 0 and B 0 s mesons. Using a sample of 8400 B * * 0 , 3300 B * * + , 1350 B * * 0 s , 2600 B(5970) 0 , and 1400 B(5970) + decays, we measure the masses and widths of all states, as well as the product of the relative production rate of B1 and B * 2 states times the branching fraction into a B 0,+ meson and a charged particle. Furthermore, we measure the branching fraction of the B * 0 s2 → B * + K − decay relative to the B * 0 s2 → B + K − decay, the production rate times the branching fraction of the B(5970) state relative to the B * 0,+ 2 state, and the production rate of the orbitally excited B 0,+ states relative to the B 0,+ ground state. The masses of the B(5970) resonance are 5978 ± 5(stat) ± 12(syst) MeV/c 2 for the neutral state and 5961 ± 5(stat) ± 12(syst) MeV/c 2 for the charged state, assuming the resonance decays to Bπ. The properties of the orbitally excited and the new B(5970) 0,+ states are compatible with isospin symmetry.
We present the first direct measurement of the W production charge asymmetry as a function of the... more We present the first direct measurement of the W production charge asymmetry as a function of the W boson rapidity yW in pp collisions at √ s = 1.96 TeV. We use a sample of W → eν events in data from 1 fb −1 of integrated luminosity collected using the CDF II detector. In the region |yW | < 3.0, this measurement is capable of constraining the ratio of up-and down-quark momentum distributions in the proton more directly than in previous measurements of the asymmetry that are functions of the charged-lepton pseudorapidity.
We report the combination of recent measurements of the helicity of the W boson from top quark de... more We report the combination of recent measurements of the helicity of the W boson from top quark decay by the CDF and D0 collaborations, based on data samples corresponding to integrated luminosities of 2.7-5.4 fb −1 of pp collisions collected during Run II of the Fermilab Tevatron Collider. Combining measurements that simultaneously determine the fractions of W bosons with longitudinal (f0) and right-handed (f+) helicities, we find f0 = 0.722 ± 0.081 [± 0.062 (stat.) ± 0.052 (syst.)] and f+ = −0.033 ± 0.046 [± 0.034 (stat.) ± 0.031 (syst.)]. Combining measurements where one of the helicity fractions is fixed to the value expected in the standard model, we find f0 = 0.682±0.057 [± 0.035 (stat.)±0.046 (syst.)] and f+ = −0.015±0.035 [± 0.018 (stat.)±0.030 (syst.)]. The results are consistent with standard model expectations.
We report on a CDF measurement of the total cross section and rapidity distribution, dσ /dy, for ... more We report on a CDF measurement of the total cross section and rapidity distribution, dσ /dy, for γ * /Z → e + e − events in the Z boson mass region (66 < M ee < 116 GeV/c 2) produced in pp collisions at √ s = 1.96 TeV with 2.1 fb −1 of integrated luminosity. The measured cross section of 257 ± 16 pb and dσ /dy distribution are compared with Next-to-Leading-Order (NLO) and Next-to-Next-to-Leading-Order (NNLO) QCD theory predictions with CTEQ and MRST/MSTW parton distribution functions (PDFs).
We present the result of a search for a massive color-octet vector particle, (e.g. a massive gluo... more We present the result of a search for a massive color-octet vector particle, (e.g. a massive gluon) decaying to a pair of top quarks in proton-antiproton collisions with a center-of-mass energy of 1.96 TeV. This search is based on 1.9 fb −1 of data collected using the CDF detector during Run II of the Tevatron at Fermilab. We study tt events in the lepton+jets channel with at least one btagged jet. A massive gluon is characterized by its mass, decay width, and the strength of its coupling to quarks. These parameters are determined according to the observed invariant mass distribution of top quark pairs. We set limits on the massive gluon coupling strength for masses between 400 and 800 GeV/c 2 and width-to-mass ratios between 0.05 and 0.50. The coupling strength of the hypothetical massive gluon to quarks is consistent with zero within the explored parameter space.
We combine searches by the CDF and D0 Collaborations for a Higgs boson decaying to W þ W À. The d... more We combine searches by the CDF and D0 Collaborations for a Higgs boson decaying to W þ W À. The data correspond to an integrated total luminosity of 4.8 (CDF) and 5.4 (D0) fb À1 of p p collisions at ffiffi ffi s p ¼ 1:96 TeV at the Fermilab Tevatron collider. No excess is observed above background expectation, and resulting limits on Higgs boson production exclude a standard model Higgs boson in the mass range 162-166 GeV at the 95% C.L.
We report measurements of direct CP-violating asymmetries in charmless decays of neutral bottom h... more We report measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb −1 of integrated luminosity, we obtain the first measurements of direct CP violation in bottom strange mesons, ACP (B 0 s → K − π +) = +0.39 ± 0.15 (stat) ± 0.08 (syst), and bottom baryons, ACP (Λ 0 b → pπ −) = +0.03 ± 0.17 (stat) ± 0.05 (syst) and ACP (Λ 0 b → pK −) = +0.37 ± 0.17 (stat) ± 0.03 (syst). In addition, we measure CP violation in B 0 → K + π − decays with 3.5σ significance, ACP (B 0 → K + π −) = −0.086 ± 0.023 (stat) ± 0.009 (syst), in agreement with the current world average. Measurements of branching fractions of B 0 s → K + K − and B 0 → π + π − decays are also updated.
Measurement of the Top Quark Mass and $p\bar{p}$ -> $t\bar{t}$ Cross Section in the All-Hadronic Mode with the CDFII Detector
Fermilab-Tevatron. Measurement of the top quark mass and TOP TOPBAR pair production cross section... more Fermilab-Tevatron. Measurement of the top quark mass and TOP TOPBAR pair production cross section in PBAR P collisions at a centre of mass energy of 1.96 TeV. Events are selected with six or more jets satisfying a number of kinematical requirements imposed by a neural-network algorithm. At least one jet must be from a b-quark identified as coming from secondary vertex inside the jet. The measured top quark mass of 174.8 +- 2.4 +1.2,-1.0 GeV is based on a likelihood fit of signal and background with the absolute jet energy scale being simultaneously measured. This procedure also derives the cross section reported here. The data sample has an integrated luminosity of 2.9 FB-1.
Top Quark Mass Measurement in the $t \bar{t}$ All Hadronic Channel using a Matrix Element Technique in $p\bar{p}$ Collisions at $\sqrt{s}$ = 1.96-TeV
We present a measurement of the top quark mass in the all-hadronic channel (\tt $\to$ \bb$q_{1}\b... more We present a measurement of the top quark mass in the all-hadronic channel (\tt $\to$ \bb$q_{1}\bar{q_{2}}q_{3}\bar{q_{4}}$) using 943 pb$^{-1}$ of \ppbar collisions at $\sqrt {s} = 1.96$ TeV collected at the CDF II detector at Fermilab (CDF). We apply the standard model production and decay matrix-element (ME) to $\ttbar$ candidate events. We calculate per-event probability densities according to the ME calculation and construct template models of signal and background. The scale of the jet energy is calibrated using additional templates formed with the invariant mass of pairs of jets. These templates form an overall likelihood function that depends on the top quark mass and on the jet energy scale (JES). We estimate both by maximizing this function. Given 72 observed events, we measure a top quark mass of 171.1 $\pm$ 3.7 (stat.+JES) $\pm$ 2.1 (syst.) GeV/$c^{2}$. The combined uncertainty on the top quark mass is 4.3 GeV/$c^{2}$.
Using the full CDF Run II data sample, we report evidence for a new resonance, which we refer to ... more Using the full CDF Run II data sample, we report evidence for a new resonance, which we refer to as B(5970), found simultaneously in the B 0 π + and B + π − mass distributions with a significance of 4.4 standard deviations. We further report the first study of resonances consistent with orbitally excited B + mesons and an updated measurement of the properties of orbitally excited B 0 and B 0 s mesons. Using a sample of 8400 B * * 0 , 3300 B * * + , 1350 B * * 0 s , 2600 B(5970) 0 , and 1400 B(5970) + decays, we measure the masses and widths of all states, as well as the product of the relative production rate of B1 and B * 2 states times the branching fraction into a B 0,+ meson and a charged particle. Furthermore, we measure the branching fraction of the B * 0 s2 → B * + K − decay relative to the B * 0 s2 → B + K − decay, the production rate times the branching fraction of the B(5970) state relative to the B * 0,+ 2 state, and the production rate of the orbitally excited B 0,+ states relative to the B 0,+ ground state. The masses of the B(5970) resonance are 5978 ± 5(stat) ± 12(syst) MeV/c 2 for the neutral state and 5961 ± 5(stat) ± 12(syst) MeV/c 2 for the charged state, assuming the resonance decays to Bπ. The properties of the orbitally excited and the new B(5970) 0,+ states are compatible with isospin symmetry.
We present the first direct measurement of the W production charge asymmetry as a function of the... more We present the first direct measurement of the W production charge asymmetry as a function of the W boson rapidity yW in pp collisions at √ s = 1.96 TeV. We use a sample of W → eν events in data from 1 fb −1 of integrated luminosity collected using the CDF II detector. In the region |yW | < 3.0, this measurement is capable of constraining the ratio of up-and down-quark momentum distributions in the proton more directly than in previous measurements of the asymmetry that are functions of the charged-lepton pseudorapidity.
We report the combination of recent measurements of the helicity of the W boson from top quark de... more We report the combination of recent measurements of the helicity of the W boson from top quark decay by the CDF and D0 collaborations, based on data samples corresponding to integrated luminosities of 2.7-5.4 fb −1 of pp collisions collected during Run II of the Fermilab Tevatron Collider. Combining measurements that simultaneously determine the fractions of W bosons with longitudinal (f0) and right-handed (f+) helicities, we find f0 = 0.722 ± 0.081 [± 0.062 (stat.) ± 0.052 (syst.)] and f+ = −0.033 ± 0.046 [± 0.034 (stat.) ± 0.031 (syst.)]. Combining measurements where one of the helicity fractions is fixed to the value expected in the standard model, we find f0 = 0.682±0.057 [± 0.035 (stat.)±0.046 (syst.)] and f+ = −0.015±0.035 [± 0.018 (stat.)±0.030 (syst.)]. The results are consistent with standard model expectations.
We report on a CDF measurement of the total cross section and rapidity distribution, dσ /dy, for ... more We report on a CDF measurement of the total cross section and rapidity distribution, dσ /dy, for γ * /Z → e + e − events in the Z boson mass region (66 < M ee < 116 GeV/c 2) produced in pp collisions at √ s = 1.96 TeV with 2.1 fb −1 of integrated luminosity. The measured cross section of 257 ± 16 pb and dσ /dy distribution are compared with Next-to-Leading-Order (NLO) and Next-to-Next-to-Leading-Order (NNLO) QCD theory predictions with CTEQ and MRST/MSTW parton distribution functions (PDFs).
We present the result of a search for a massive color-octet vector particle, (e.g. a massive gluo... more We present the result of a search for a massive color-octet vector particle, (e.g. a massive gluon) decaying to a pair of top quarks in proton-antiproton collisions with a center-of-mass energy of 1.96 TeV. This search is based on 1.9 fb −1 of data collected using the CDF detector during Run II of the Tevatron at Fermilab. We study tt events in the lepton+jets channel with at least one btagged jet. A massive gluon is characterized by its mass, decay width, and the strength of its coupling to quarks. These parameters are determined according to the observed invariant mass distribution of top quark pairs. We set limits on the massive gluon coupling strength for masses between 400 and 800 GeV/c 2 and width-to-mass ratios between 0.05 and 0.50. The coupling strength of the hypothetical massive gluon to quarks is consistent with zero within the explored parameter space.
We combine searches by the CDF and D0 Collaborations for a Higgs boson decaying to W þ W À. The d... more We combine searches by the CDF and D0 Collaborations for a Higgs boson decaying to W þ W À. The data correspond to an integrated total luminosity of 4.8 (CDF) and 5.4 (D0) fb À1 of p p collisions at ffiffi ffi s p ¼ 1:96 TeV at the Fermilab Tevatron collider. No excess is observed above background expectation, and resulting limits on Higgs boson production exclude a standard model Higgs boson in the mass range 162-166 GeV at the 95% C.L.
We report measurements of direct CP-violating asymmetries in charmless decays of neutral bottom h... more We report measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb −1 of integrated luminosity, we obtain the first measurements of direct CP violation in bottom strange mesons, ACP (B 0 s → K − π +) = +0.39 ± 0.15 (stat) ± 0.08 (syst), and bottom baryons, ACP (Λ 0 b → pπ −) = +0.03 ± 0.17 (stat) ± 0.05 (syst) and ACP (Λ 0 b → pK −) = +0.37 ± 0.17 (stat) ± 0.03 (syst). In addition, we measure CP violation in B 0 → K + π − decays with 3.5σ significance, ACP (B 0 → K + π −) = −0.086 ± 0.023 (stat) ± 0.009 (syst), in agreement with the current world average. Measurements of branching fractions of B 0 s → K + K − and B 0 → π + π − decays are also updated.
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