Download or read book The Search for Second Generation Leptoquarks at Run II D in the mu mu Jj Channel in square Root S written by Xiaofei Song and published by . This book was released on 2005 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for First and Second Generation Leptoquarks at written by and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Direct Searches for Scalar Leptoquarks at the Run II Tevatron written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation sets new limits on the mass of the scalar leptoquark from direct searches carried out at the Run II CDF detector using data from March 2001 to October 2003. The data analyzed has a total time-integrated measured luminosity of 198 pb[sup -1] of p[bar p] collisions with [radical]s = 1.96 TeV. Leptoquarks are assumed to be pair-produced and to decay into a lepton and a quark of the same generation. They consider two possible leptoquark decays: (1) [beta] = BR(LQ [yields] [mu]q) = 1.0, and (2) [beta] = BR(LQ [yields] [mu]q) = 0.5. For the [beta] = 1 channel, they focus on the signature represented by two isolated high-p[sub T] muons and two isolated high-p[sub T] jets. For the [beta] = 1/2 channel, they focus on the signature represented by one isolated high-p[sub T] muon, large missing transverse energy, and two isolated high-p[sub T] jets. No leptoquark signal is experimentally detected for either signature. Using the next to leading order theoretical cross section for scalar leptoquark production in p[bar p] collisions [1], they set new mass limits on second generation scalar leptoquarks. They exclude the existence of second generation scalar leptoquarks with masses below 221(175) GeV/c[sup 2] for the [beta] = 1(1/2) channels.
Download or read book Search for First Generation Leptoquarks in the Evjj and Eejj Decay Channels in Pp Collisions at square Root Of s written by Federica Strumia and published by . This book was released on 2001 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for Pair Production of Second Generation Scalar Leptoquarks in P Anti p Collisions at S 1 2 written by and published by . This book was released on 2006 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors report on a search for the pair production of second generation scalar leptoquarks (LQ2) in p{bar p} collisions at the center-of-mass energy √s = 1.96 TeV, using data corresponding to an integrated luminosity of 294 ± 19 pb−1 recorded with the D0 detector. No evidence for a leptoquark signal in the LQ2 {ovr LQ}2 → [mu]q[mu]q channel has been observed, and upper bounds on the product of cross section times branching fraction were set. This yields lower mass limits of m{sub LQ2} > 247 GeV for [beta] = [Beta](LQ{sub 2} → [mu]q) = 1 and m{sub LQ{sub 2}} > 182 GeV for [beta] = 1/2. Combining these limits with previous D0 results, the lower limits on the mass of a second generation scalar leptoquark are m{sub LQ{sub 2}} > 251 GeV and m{sub LQ{sub 2}} > 204 GeV for [beta] = 1 and [beta] = 1/2, respectively.
Download or read book Search for Second Generation Leptoquarks at CDF written by and published by . This book was released on 1994 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the results of a search for second generation leptoquarks S2 in p{bar p} collisions at √s = 1.8 TeV at the Fermilab Tevatron. This search is based on 19.3 pb− of data collected during the 1992--93 CDF run. We have searched for evidence of leptoquark pairs assuming that ea& leptoquark decays to a muon+quark with a branching ratios. Two leptoquark candidate events were found with a background of 1.35±0.50. We obtained-upper limits on the production cross-section times branching ratio as a function of leptoquark mass. For pair production of second generation leptoquarks, we excluded M{sub S}2
Download or read book Search for First Generation Leptoquarks in the e nu jj and eejj Decay Channels in p Pbar Collisions at sqrt s written by Federica Strumia and published by . This book was released on 2001 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: Le sujet de cette thèse est la recherche des leptoquarks scalaires et vectoriels de première génération produits en couple dans des collisions proton-antiproton à une énergie du centre de masse de 1.8 TeV et se désintégrant dans les canaux "e[nu]jj" et "eejj". L'analyse a été conduite sur les données récoltées par l'expérience CDF pendant la période 1992-1995.
Download or read book Search for 3rd Generation Vector Leptoquarks in the Di tau Di jet Channel in Pp Collisions at square Root Of S written by Stanley Scott Forrester and published by . This book was released on 2006 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for Second generation Scalar Leptoquarks in P Anti p Collisions at S 1 2 written by and published by . This book was released on 2005 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results on a search for pair production of second generation scalar leptoquark in p{bar p} collisions at √s=1.96 TeV are reported. The data analyzed were collected by the CDF detector during the 2002-2003 Tevatron Run II and correspond to an integrated luminosity of 198 pb−1. Leptoquarks (LQ) are sought through their decay into (charged) leptons and quarks, with final state signatures represented by two muons and jets and one muon, large transverse missing energy and jets. We observe no evidence for LQ production and derive 95% C.L. upper limits on the LQ production cross sections as well as lower limits on their mass as a function of [beta], where [beta] is the branching fraction for LQ → [mu]q.
Download or read book A Search for First Generation Scalar Leptoquarks at square Root s written by and published by . This book was released on 1993 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for first generation scalar leptoquarks was done at the DO detector at Fermi National Accelerator Laboratory from 15 pb-1 of data taken during the 1992--1993 colder run. At Fermilab's p{bar p} collider with a center-of-mass energy of 1.8 TeV, leptoquarks are produced mostly by the strong force in pairs. Leptoquarks carry fractional charge, color, and also lepton and baryon quantum numbers. First generation leptoquarks couple exclusively to the electron, electron neutrino, and the u and d quarks; such a leptoquark would decay into, for example, an electron plus a quark. Signatures for leptoquarks at p{bar p} colliders that have been investigated at DO are two electrons plus two jets and one electron plus missing energy (from an electron neutrino) plus two jets.
Download or read book Seach for Second Generation Leptoquarks in Proton Anti proton Collisions written by Tim U. Christiansen and published by . This book was released on 2003 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: This document describes the search for second-generation leptoquarks (LQ{sub 2}) in around 114pb{sup -1} of p{bar p} collisions, recorded with the D0 detector between September 2002 and June 2003 at a centre-of-mass energy of {radical}s = 1.96TeV. The predictions of the Standard Model and models including scalar leptoquark production are compared to the data for various kinematic distributions. Since no excess of data over the Standard Model prediction has been observed, a lower limit on the leptoquark mass of M{sub LQ{sub 2}}{sup {beta}=1}> 200GeV has been calculated at 95% confidence level (C.L.), assuming a branching fraction of {beta} = BF(LQ{sub 2} {yields} {mu}j) = 100% into a charged lepton and a quark. The corresponding limit for {beta} = 1/2 is M{sub LQ{sub 2}}{sup {beta}=1/2}> 152 GeV. Finally, the results were combined with those from the search in the same channel at D0 Run I. This combination yields the exclusion limit of M{sub LQ{sub 2}}{sup {beta}=1}> 222 GeV (177GeV) for (beta) = 1 (1/2) at 95% C.L., which is the best exclusion limit for scalar second-generation leptoquarks (for {beta} = 1) from a single experiment to date.
Download or read book Search for 3rd Generation Vector Leptoquarks in the Di tau Di jet Channel in Proton Antiproton Collisions at Square Root S written by Stanley Scott Forrester and published by . This book was released on 2006 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: We search for third generation vector leptoquarks (V LQ3) produced in colliding p{bar p} beams operating at {radical}s = 1.96 TeV at the CDF experiment in Run II of the Fermilab Tevatron. We use 322 pb{sup -1} of data to search for the V LQ3 signal in the di-tau plus di-jet channel. For the first time, the full matrix element is used in the Monte Carlo simulation of this signal. With no events observed in the signal region, we set a 95% C.L. upper limit on the V LQ3 pair production cross section of {sigma} 344fb, assuming Yang-Mills couplings and Br(V LQ3 {yields} b{tau}) = 1, and a lower limit on the V LQ3 mass of m{sub V LQ3} 317 GeV=c{sup 2}. If theoretical uncertainties on the cross section are applied in the least favorable manner the results are {sigma} 360fb and m{sub V LQ3} 294 GeV=c{sup 2}. The Minimal coupling V LQ3 result is an upper limit on the cross section of {sigma} 493fb ({sigma} 610fb) and the lower limit on the mass is m{sub V LQ3} 251 GeV=c{sup 2} (m{sub V LQ3} 223 GeV=c{sup 2}) for the nominal (1{sigma} varied) theoretical expectation.
Download or read book Direct Searches for Scalar Leptoquarks at the Run II Tevatron written by Daniel Edward Ryan and published by . This book was released on 2004 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation sets new limits on the mass of the scalar leptoquark from direct searches carried out at the Run II CDF detector using data from March 2001 to October 2003. The data analysed has a total time-integrated measured luminosity of 198 pb-1 of pp ̄ collisions with s = 1.96 TeV. Leptoquarks are assumed to be pair-produced and to decay into a lepton and a quark of the same generation. We consider two possible leptoquark decays: (1) beta = BR(LQ → muq ) = 1.0, and (2) beta = BR(LQ → muq ) = 0.5. For the beta = 1 channel, we focus on the signature represented by two isolated high-pT muons and two isolated high-pT jets. For the beta = 1/2 channel, we focus on the signature represented by one isolated high-pT muon, large missing transverse energy, and two isolated high-p T jets. No leptoquark signal is experimentally detected for either signature. Using the next to leading order theoretical cross section for scalar leptoquark production in pp ̄ collisions [1], we set new mass limits on second generation scalar leptoquarks. We exclude the existence of second generation scalar leptoquarks with masses below 221(175) GeV/c2 for the beta = 1(1/2) channels.
Download or read book Search for Pair Production of Second Generation Scalar Leptoquarks in Ppbar Collisions at the Tevatron written by and published by . This book was released on 2008 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: As predicted by numerous extensions of the Standard Model, leptoquarks (LQ) are hypothetical bosons allowing lepton-quark transitions. Under the assumption that they couple only to quarks and leptons of the same generation, three generations of leptoquarks can be distinguished. The search for the pair production of second generation scalar leptoquarks has been carried out in p{bar p} collisions at √s = 1.96TeV, using an integrated luminosity of 1 fb−1 collected by the D0 experiment at the Tevatron collider between August 2002 and February 2006. Topologies arising from the LQ{ovr LQ} → [mu]q[nu]q and LQ{ovr LQ} → [mu]q[mu]q decay modes have been investigated. In order to maximize the available statistics, a method for the combination of various prescaled triggers with an inclusive OR has been developed. Since no excess of data over the Standard Model prediction has been observed, upper limits on the leptoquark pair production cross section have been derived at 95% confidence level as function of the leptoquark mass and the branching fraction [beta] = Br(LQ → [mu]q), and are interpreted as lower limits on the leptoquark mass as function of [beta]. For [beta] = 1, [beta] = 1/2 and [beta] = 0.1, the combination of the two channels excludes scalar second generation leptoquarks with masses up to 309GeV, 262GeV, and 174GeV, respectively. The lower bounds on the scalar second generation leptoquark mass obtained for [beta] ≥ 0.1 are the best exclusion limits to date.
Download or read book Search for Pair Production of First and Second Generation Leptoquarks in Proton proton Collisions at sqrt s written by and published by . This book was released on 2015 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our search for pair production of first and second generation leptoquarks is performed in final states containing either two charged leptons and two jets, or one charged lepton, one neutrino and two jets, using proton-proton collision data at √s = 8 TeV. The data, corresponding to an integrated luminosity of 19.7 fb-1, were recorded with the CMS detector at the LHC. First-generation scalar leptoquarks with masses less than 1010 (850) GeV are excluded for [beta] = 1.0 (0.5), where b is the branching fraction of a leptoquark decaying to a charged lepton and a quark. Similarly, secondgeneration scalar leptoquarks with masses less than 1080 (760) GeV are excluded for [beta] = 1.0 (0.5). Furthermore, mass limits are also set for vector leptoquark production scenarios with anomalous vector couplings, and for R-parity violating supersymmetric scenarios of top squark pair production resulting in similar final-state signatures. These are the most stringent limits placed on the masses of leptoquarks and RPV top squarks to date.
Download or read book Search for Pair Production of Second Generation Scalar Leptoquarks written by and published by . This book was released on 2008 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on a search for the pair production of second generation scalar leptoquarks (LQ) in p{bar p} collisions at the center of mass energy √s = 1.96TeV using a data set corresponding to an integrated luminosity of 1.0 fb−1 collected with the D0 experiment at the Fermilab Tevatron Collider. Topologies arising from the LQ{ovr LQ} → [mu]q[nu]q and LQ{ovr LQ} → [mu]q[mu]q decay modes are investigated. No excess of data over the standard model prediction is observed and upper limits on the leptoquark pair production cross section are derived at the 95% C.L. as a function of the leptoquark mass and the branching fraction [beta] for the decay LQ → [mu]q. These are interpreted as lower limits on the leptoquark mass as a function of [beta]. For [beta] = 1 (0.5), scalar second generation leptoquarks with masses up to 316GeV (270GeV) are excluded.
Download or read book Seach for Second Generation Leptoquarks in Proton Anti proton Collisions written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the study presented in this document, about 114 pb[sup -1] of p[bar p] collisions from Run II, collected with the D0 detector between September 2002 and June 2003, are compared to Standard-Model predictions and predictions from models including scalar second-generation leptoquarks. since no deviation from the Standard Model is observed, upper limits on the leptoquark cross-section are calculated and translated into lower bounds to the mass of scalar leptoquarks. Consequently, the results are combined with earlier results from D0 Run I in the same channel.
