Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 7
Book Description
Search for Right-handed W Bosons in Top Quark Decay
Author: Search for W-prime Boson Production in the Top Quark Decay Channel
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 9
Book Description
We present a search for the production of a new heavy gauge boson W' that decays to a top quark and a bottom quark. We have analyzed 230 pb−1 of data collected with the D0 detector at the Fermilab Tevatron collider at a center-of-mass energy of 1.96 TeV. No significant excess of events is found in any region of the final state invariant mass distribution. We set upper limits on the production cross section of W bosons at the 95% confidence level for several different W' boson masses. We exclude masses below 610 GeV for a W' boson with standard-model-like couplings, below 630 GeV for a W' boson with right-handed couplings that is allowed to decay to both leptons and quarks, and below 670 GeV for a W' boson with right-handed couplings that is only allowed to decay to quarks.
Search for W' Boson with Boosted and Hadronic Top-quark Final State in Pp Collisions at 8́(s
Author: Kuan-Yu LinPublisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 181
Book Description
With the LHC proton-proton collision data at an energy of 13 TeV recorded by the ATLAS detector, this analysis searches for the production of a new particle W' with a yet-to-be-probed mass in the top quark plus bottom quark decay channel. The boosted and hadronically decaying top-quark is reconstructed as a large-radius jet and identified using jet substructures. A secondary-vertex finding algorithm identifies small-radius jets originating from a bottom quark. After the identification stage, the main background events come from the Quantum Chromodynamical production of multi-jet, which is estimated by a data-driven approach. The statistical data analysis searches for a resonant peak in the invariant mass distribution of the system with a jet associated with the top quark and another with the bottom quark. The consistency between data and the background prediction is found in the invariant mass range between 1 TeV to 7 TeV, and an upper limit at the 95% confidence level is set on the production cross-section times branching ratio for a W' boson with right-handed chirality decaying to a top quark and a bottom quark. A lower limit on the W' mass is set at 4.4 TeV accordingly.
Search for $W' \to Tb$ in Proton-proton Collisions at $\sqrt{s}
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 42
Book Description
A search is performed for the production of a massive W' boson decaying to a top and a bottom quark. The data analysed correspond to an integrated luminosity of 19.7 fb$^{{u2013}1}$ collected with the CMS detector at the LHC in proton-proton collisions at $ \sqrt{s}=8 $ TeV. The hadronic decay products of the top quark with high Lorentz boost from the W' boson decay are detected as a single top flavoured jet. The use of jet substructure algorithms allows the top quark jet to be distinguished from standard model QCD background. Limits on the production cross section of a right-handed W' boson are obtained, together with constraints on the left-handed and right-handed couplings of the W' boson to quarks. The production of a right-handed W' boson with a mass below 2.02 TeV decaying to a hadronic final state is excluded at 95% confidence level. Furthermore, this mass limit increases to 2.15 TeV when both hadronic and leptonic decays are considered, and is the most stringent lower mass limit to date in the tb decay mode.
Search for W-prime Boson Resonances Decaying to a Top Quark and a Bottom Quark
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 7
Book Description
We search for the production of a heavy W(prime) gauge boson that decays to third generation quarks in 0.9 fb−1 of p{bar p} collisions at (square root)s = 1.96 TeV, collected with the D0 detector at the Fermilab Tevatron collider. We find no significant excess in the final-state invariant mass distribution and set upper limits on the production cross section times branching fraction. For a left-handed W(prime) boson with SM couplings, we set a lower mass limit of 731 GeV. For right-handed W(prime) bosons, we set lower mass limits of 739 GeV if the W(prime) boson decays to both leptons and quarks and 768 GeV if the W(prime) boson decays only to quarks. We also set limits on the coupling of the W(prime) boson to fermions as a function of its mass.
Measurement of the Helicity of W Bosons in Top-quark Decays
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 7
Book Description
We measure the branching fraction of the top quark to longitudinally and right-handed polarized W bosons, F0 and F+, using approximately 200 pb−1 of p{bar p} collisions collected by the CDF II detector. We analyze two quantities sensitive to the W helicity: the invariant mass of the charged lepton and the bottom-quark jet in the decay t 2!Wb 2!l[nu]b (where l = e or [mu]), and the transverse momentum of the charged lepton. We find F0 = 0.74{sub -0.34}{sup +0.22}, and F+
Top Quark Physics at Hadron Colliders
Author: Arnulf QuadtPublisher: Springer Science & Business Media
ISBN: 3540710604
Category : Science
Languages : en
Pages : 166
Book Description
This will be a required acquisition text for academic libraries. More than ten years after its discovery, still relatively little is known about the top quark, the heaviest known elementary particle. This extensive survey summarizes and reviews top-quark physics based on the precision measurements at the Fermilab Tevatron Collider, as well as examining in detail the sensitivity of these experiments to new physics. Finally, the author provides an overview of top quark physics at the Large Hadron Collider.
Measurement of the W Boson Helicity in Top Quark Decay at
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 7
Book Description
The authors present a measurement of the fraction f+ of right-handed W bosons produced in top quark decays, based on a candidate sample of t{bar t} events in the l+jets and dilepton decay channels corresponding to an integrated luminosity of 370 pb−1 collected by the D0 detector at the Fermilab Tevatron p{bar p} Collider at √s = 1.96 TeV. They reconstruct the decay angle [theta]* for each lepton. By comparing the cos[theta]* distribution from the data with those for the expected background and signal for various values of f+, they find f+ = 0.056 ± 0.080(stat) ± 0.057(syst). (f+
A Search for Right-handed W Bosons in P̄p Collisions with the DØ Detector at Fermilab
Author: Azriel GoldschmidtModel-independent Measurement of the W Boson Helicity in Top Quark Decays at
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 8
Book Description
We present the first model-independent measurement of the helicity of W bosons produced in top quark decays, based on a 1 fb−1 sample of candidate t{bar t} events in the dilepton and lepton plus jets channels collected by the D0 detector at the Fermilab Tevatron p{bar p} Collider. We reconstruct the angle [theta]* between the momenta of the down-type fermion and the top quark in the W boson rest frame for each top quark decay. A fit of the resulting cos [theta]* distribution finds that the fraction of longitudinal W bosons f0 = 0.390 ± 0.177 (stat.) ± 0.104 (syst.) and the fraction of right-handed W bosons f+ = 0.171 ± 0.102 (stat.) ± 0.058 (syst.), which is consistent at the 27% C.L. with the standard model.