Search for Scalar Bottom Quarks from Gluino Decays in Proton - Anti-proton Collisions at a Center-of-Mass Energy of 1.96-TeV.
Search for Scalar Bottom Quarks from Gluino Decays in Proton - Anti-proton Collisions at a Center-of-Mass Energy of 1.96-TeV.

Author: Carsten Rott

Publisher:

Published: 2004

Total Pages: 185

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The authors have performed a search for the scalar bottom quark ({tilde b}{sub 1}) from gluino ({tilde g}) decays in an R-parity conserving SUSY scenario with m{sub {tilde g}}> m{sub {tilde b}{sub 1}}, by investigating a final state of large missing transverse energy, with three or more jets, and some of them from the hadronization of b-quarks. A data sample of 156 pb{sup -1} collected by the Collider Detector at Fermilab at a center-of-mass energy of {radical}s = 1.96 TeV was used. For the final selection, jets containing secondary displaced vertices were required. This analysis has been performed ''blind'', in that the inspection of the signal region was only made after the Standard Model prediction was finalized. Comparing data with SUSY predictions, they can exclude masses of the gluino and sbottom of up to 280 and 240 GeV/c{sup 2} respectively.

A Search for Scalar Bottom Quarks from Gluino Decays in Anti-p P Collisions at S**ư
A Search for Scalar Bottom Quarks from Gluino Decays in Anti-p P Collisions at S**ư

Author:

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Published: 2005

Total Pages: 7

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We searched for scalar bottom quarks in 156 pb−1 of {bar p}p collisions at √s = 1.96 TeV recorded by the CDF II experiment at the Tevatron. Scalar bottom quarks can be produced from gluino decays in R-parity conserving models of supersymmetry when the mass of the gluino exceeds that of the scalar bottom quark. Then, a scalar bottom quark can decay into a bottom quark and a neutralino. To search for this scenario, we investigated events with large missing transverse energy and at least three jets, two or more of which were identified as containing a secondary vertex from the hadronization of b quarks. We found four candidate events, where 2.6 ± 0.7 are expected from standard model processes, and placed 95% confidence level lower limits on gluino and scalar bottom quark masses of up to 280 and 240 GeV/c2, respectively.

A Search for Scalar Bottom Quarks from Gluino Decays in Anti-p P Collisions at S**1/2
A Search for Scalar Bottom Quarks from Gluino Decays in Anti-p P Collisions at S**1/2

Author:

Publisher:

Published: 2005

Total Pages: 7

ISBN-13:

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We searched for scalar bottom quarks in 156 pb−1 of {bar p}p collisions at √s = 1.96 TeV recorded by the CDF II experiment at the Tevatron. Scalar bottom quarks can be produced from gluino decays in R-parity conserving models of supersymmetry when the mass of the gluino exceeds that of the scalar bottom quark. Then, a scalar bottom quark can decay into a bottom quark and a neutralino. To search for this scenario, we investigated events with large missing transverse energy and at least three jets, two or more of which were identified as containing a secondary vertex from the hadronization of b quarks. We found four candidate events, where 2.6 ± 0.7 are expected from standard model processes, and placed 95% confidence level lower limits on gluino and scalar bottom quark masses of up to 280 and 240 GeV/c2 , respectively.

A Search for Top Quarks in Proton-antiproton Collisions Using Dileptons
A Search for Top Quarks in Proton-antiproton Collisions Using Dileptons

Author: Andrew James Martin

Publisher:

Published: 1996

Total Pages:

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A search for tt pairs in pp collisions with a center of mass energy $sqrt s$ = 1.8TeV is presented. The analysis looks for tt pairs which decayed through the chain $bar {tt}to Wsp+bWsp-bar btoellsp+bar nu bellsp-nubar b$ where one of the b quarks is explicitly identified. In a sample of 109.4 $pm$ 7.2 pb$sp{-1}$ of data, 6 tags in 4 events are found with an expected background of 1.53 $pm$.33 events. This results in an estimated production cross section of 4.6$sbsp{-3.1}{+4.4}$ pb at $msb{top}$ = 175 GeV/$csp2.$

Search for Third-Generation Scalar Leptoquarks in the T$\tau$ Channel in Proton-Proton Collisions at $\sqrt{s}$
Search for Third-Generation Scalar Leptoquarks in the T$\tau$ Channel in Proton-Proton Collisions at $\sqrt{s}$

Author:

Publisher:

Published: 2015

Total Pages: 41

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A search for pair production of third-generation scalar leptoquarks decaying to top quark and $\tau$ lepton pairs is presented using proton-proton collision data at a center-of-mass energy of $\sqrt{s}$ = 8 TeV collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 19.7 fb-1. The search is performed using events that contain an electron or a muon, a hadronically decaying $\tau$ lepton, and two or more jets. The observations are found to be consistent with the standard model predictions. Assuming that all leptoquarks decay to a top quark and a $\tau$ lepton, the existence of pair produced, charge -1/3, third-generation leptoquarks up to a mass of 685 GeV is excluded at 95% confidence level. This result constitutes the first direct limit for leptoquarks decaying into a top quark and a $\tau$ lepton, and may also be applied directly to the pair production of bottom squarks decaying predominantly via the R-parity violating coupling [lambda]' 333.

Search for Resonances Decaying to Top and Bottom Quarks with the CDF Experiment
Search for Resonances Decaying to Top and Bottom Quarks with the CDF Experiment

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Published: 2015

Total Pages:

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We report on a search for charged massive resonances decaying to top (t) and bottom (b) quarks in the full data set of proton-antiproton collisions at a center-of-mass energy of √s = 1.96 TeV collected by the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.5 fb-1. No significant excess above the standard model background prediction is observed. We set 95% Bayesian credibility mass-dependent upper limits on the heavy charged-particle production cross section times branching ratio to tb. Using a standard model extension with a W' → tb and left-right-symmetric couplings as a benchmark model, we constrain the W' mass and couplings in the 300-900 GeV/c2 range. As a result, the limits presented here are the most stringent for a charged resonance with mass in the range 300-600 GeV/c2 decaying to top and bottom quarks.

Search for the Supersymmetric Partner of the Top Quark in Ppbar Collisions at Sqrt(s)
Search for the Supersymmetric Partner of the Top Quark in Ppbar Collisions at Sqrt(s)

Author:

Publisher:

Published: 2010

Total Pages: 17

ISBN-13:

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We present a search for the lightest supersymmetric partner of the top quark in proton-antiproton collisions at a center-of-mass energy (square root)s = 1.96 TeV. This search was conducted within the framework of the R-parity conserving minimal supersymmetric extension of the standard model, assuming the stop decays dominantly to a lepton, a sneutrino, and a bottom quark. We searched for events with two oppositely-charged leptons, at least one jet, and missing transverse energy in a data sample corresponding to an integrated luminosity of 1 fb−1 collected by the CDF experiment. No significant evidence of a stop quark signal was found. Exclusion limits at 95% confidence level in the stop quark versus sneutrino mass plane are set. Stop quark masses up to 180 GeV/c2 are excluded for sneutrino masses around 45 GeV/c2, and sneutrino masses up to 116 GeV/c2 are excluded for stop quark masses around 150 GeV/c2.