Measurement of the ratio of top-quark branching fractions top quark decaying to W boson and bottom quark and top quark decaying to W boson and any quark in the lepton + jets and dilepton channels at the Collider Detector at Fermilab

2005 ◽  
Author(s):  
Dmitri Smirnov
Keyword(s):  
Top Quark ◽  
W Boson ◽  
Branching Fractions ◽  
Bottom Quark ◽  
Lepton Jets ◽  
Dilepton Channels

scholarly journals Measurement of the W boson helicity fractions in the decays of top quark pairs to lepton + jets final states produced in pp collisions at s=8TeV

2016 ◽  
Vol 762 ◽  
pp. 512-534 ◽  
Author(s):  
V. Khachatryan ◽  
A.M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
E. Asilar ◽  
...  
Keyword(s):  
Top Quark ◽  
W Boson ◽  
Final States ◽  
Pp Collisions ◽  
Quark Pairs ◽  
Lepton Jets ◽  
Top Quark Pairs

scholarly journals CONVOLUTION FORMULA AND FINITE W BOSON WIDTH EFFECTS IN TOP QUARK WIDTH

2008 ◽  
Vol 23 (22) ◽  
pp. 3525-3533 ◽  
Author(s):  
G. CALDERÓN ◽  
G. LÓPEZ CASTRO
Keyword(s):  
Top Quark ◽  
W Boson ◽  
Matrix Theory ◽  
Finite Width ◽  
Current Limit ◽  
Fermion Masses ◽  
Convolution Formula ◽  
Boson Resonance ◽  
Three Body ◽  
Massless Fermions

In the Standard Model, the top quark decay width Γt is computed from the exclusive t → bW decay. We argue in favor of using the three body decays [Formula: see text] to compute Γt as a sum over these exclusive modes. As dictated by the S-matrix theory, these three body decays of the top quark involve only asymptotic states and incorporate the width of the W boson resonance in a natural way. The convolution formula commonly used to include the finite width effects is found to be valid, in the general case, when the intermediate resonance couples to a conserved current (limit of massless fermions in the case of W bosons). The relation Γt = Γ(t → bW) is recovered by taking the limit of massless fermions followed by the W boson narrow width approximation. Although both calculations of Γt are different at the formal level, their results would differ only by tiny effects induced by light fermion masses and higher-order radiative corrections.

MEASUREMENT OF THE TOP QUARK PAIR PRODUCTION CROSS SECTION IN LEPTON+JETS FINAL STATES AT DØ USING A MULTIVARIATE TECHNIQUE

2005 ◽  
Vol 20 (14) ◽  
pp. 3177-3179
Author(s):  
◽  
TOBIAS GOLLING
Keyword(s):  
Pair Production ◽  
Cross Section ◽  
Top Quark ◽  
Production Cross Section ◽  
Production Cross ◽  
Final States ◽  
Multivariate Technique ◽  
Text Production ◽  
Lepton Jets ◽  
Pair Production Cross Section

A measurement of the [Formula: see text] production cross-section at [Formula: see text] with the DØ detector at the Fermilab Tevatron, based on the application of a multivariate topological method is presented. The integrated luminosity corresponds to 143.9 pb-1 in the μ+jets and 141.2 pb-1 in the e+jets channel. The preliminary cross-section is measured to be [Formula: see text].

Helicity of the W in Single-Lepton $t\bar{t}$ Events

2003 ◽  
Vol 18 (supp01) ◽  
pp. 304-319
Author(s):  
Florencia Canelli
Keyword(s):  
Maximum Likelihood ◽  
Maximum Likelihood Method ◽  
W Boson ◽  
W Bosons ◽  
Likelihood Method ◽  
Final States ◽  
Left Handed ◽  
Lepton Jets

We have developed a procedure to study the helicity of the W boson in [Formula: see text] events. Using events generated with the PYTHIA program at a top Mt = 175 GeV/c2, we employ a maximum likelihood method to extract the fraction of right-handed, longitudinal and left-handed W bosons in top decays. Assuming V–A coupling in the decay, we obtain a longitudinal fraction of 0.696±0.097 for 50 simulated experiments of 100 events in lepton+jets [Formula: see text] final states, a result that is consistent with the input fraction of 0.703.

Sign in / Sign up

Export Citation Format

Share Document