Download or read book A Search for Generation 1 Leptoquarks in Proton Anti proton Collisions at S 1 2 written by and published by . This book was released on 1993 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Search for Generation 1 Leptoquarks in Proton antiproton Collisions at square Root s written by Steven M. Moulding and published by . This book was released on 1993 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Search for First Generation Leptoquarks in Proton antiproton Collisions at the Center of Mass Energy written by Shaohua Fu and published by . This book was released on 2004 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Search for First Generation Leptoquarks in Proton antiproton Collisions at the Center of Mass Energy written by and published by . This book was released on 2004 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt: We describe a search for first generation leptoquarks decaying into the eejj final state in $p\bar{p}$ collisions at a center of mass energy of 1.96 TeV using the D0 detector at the Fermilab Tevatron. this search is based on data collected during 2002-2003 with an integrated luminosity of (130.4 =- 8.5) pb -1. Leptoquarks are assumed to be produced in pairs and to decay into an electron and a quark with a branching ration ?. We observe no evidence for leptoquarks, and set an upper cross section limit of 0.086 pb at the 95% confidence level corresponding to a lower mass limit of 231 GeV/c2 for scalar leptoquarks when ? = 1.

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 First Generation Scalar Leptoquarks in Proton antiproton Collisions at a Center of Mass Energy of 1 8 TeV with the D Detector written by Guoliang Wang and published by . This book was released on 1997 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Search for First generation Leptoquarks in the Jets and Missing Transverse Energy Topology in Proton antiproton Collisions at Center of mass Energy 1 96 TeV written by Dmitri Tsybychev and published by . This book was released on 2004 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

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 Single Production of Scalar Leptoquarks in Proton proton Collisions at S written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper, a search is presented for the production of both first- and second-generation scalar leptoquarks with a final state of either two electrons and one jet or two muons and one jet. The search is based on a data sample of proton-proton collisions at center-of-mass energy √s =8 TeV recorded with the CMS detector and corresponding to an integrated luminosity of 19.6 fb-1. Upper limits are set on both the first- and second-generation leptoquark production cross sections as functions of the leptoquark mass and the leptoquark couplings to a lepton and a quark. Results are compared with theoretical predictions to obtain lower limits on the leptoquark mass. At 95% confidence level, single production of first-generation leptoquarks with a coupling and branching fraction of 1.0 is excluded for masses below 1730 GeV, and second-generation leptoquarks with a coupling and branching fraction of 1.0 is excluded for masses below 530 GeV. Finally, these are the best overall limits on the production of first-generation leptoquarks to date.

Download or read book Search for Third Generation Vector Leptoquarks in 1 96 TeV Proton antiproton Collisions written by and published by . This book was released on 2007 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: The CDF experiment has searched for production of a third generation vector leptoquark (VLQ3) in the di-tau plus di-jet channel using 322 pb−1 of Run II data. We review the production and decay theory and describe the VLQ3 model we have used as a benchmark. We study the analysis, including the data sample, triggers, particle identification, and event selection. We also discuss background estimates and systematic uncertainties. We have found no evidence for VLQ3 production and have set a 95% C.L. upper limit on the pair production cross section [sigma] to 344 fb, and exclude VLQ3 in the mass range m{sub VLQ3}> 317 GeV/c2, assuming Yang-Mills couplings and Br(LQ3 2!b[tau]) = 1. If theoretical uncertainties on the cross section are taken into account, the results are [sigma] 353 fb and m{sub VLQ3} 303 GeV/c2. For a VLQ3 with Minimal couplings, the upper limit on the cross section is [sigma] 493 fb ([sigma] 554 fb) and the lower limit on the mass is m{sub VLQ3} 251 GeV/c2 (m{sub VLQ3} 235 GeV/c2) for the nominal (1[sigma] varied) theoretical expectation.

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 Search for Third Generation Scalar Leptoquarks in the T tau Channel in Proton Proton Collisions at sqrt s written by and published by . This book was released on 2015 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Search for 3rd Generation Vector Leptoquarks in the Di tau Di jet Channel in Proton Antiproton Collisions at Square u221A s written by 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$ar{p}$ beams operating at √s = 1.96 TeV at the CDF experiment in Run II of the Fermilab Tevatron. We use 322 pb-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 ? 344fb, assuming Yang-Mills couplings and Br(V LQ3 → b?) = 1, and a lower limit on the V LQ3 mass of msubV LQ3/sub 317 GeV=c2. If theoretical uncertainties on the cross section are applied in the least favorable manner the results are ? 360fb and msubV LQ3/sub 294 GeV=c2. The Minimal coupling V LQ3 result is an upper limit on the cross section of ? 493fb (? 610fb) and the lower limit on the mass is msubV LQ3/sub 251 GeV=csup2/sup (msubV LQ3/sub 223 GeV=c2) for the nominal (1? varied) theoretical expectation.

Download or read book Search for Pair Production of First Or Second Generation Leptoquarks in Proton Proton Collisions at Sqrt s written by and published by . This book was released on 2013 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Exotic Physics written by D. Acosta and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on a search for the pair production of scalar leptoquarks, LQ, using 191 pb{sup -1} of proton-antiproton collision data recorded by the CDF experiment during Run II of the Tevatron. The leptoquarks are sought via their decay into a neutrino and quark yielding missing transverse energy and several jets of large transverse energy. No evidence for leptoquark production is observed, and limits are set on {sigma}(p{bar p} {yields} LQ{ovr OQ}X {yields} v{bar v}q{bar q}X). Using a next-to-leading order theoretical prediction of the cross section for scalar leptoquark production, we exclude first-generation leptoquarks in the mass interval 78 to 117 GeV/c{sup 2} at the 95% confidence level for BR(LQ {yields} vq) = 100%.

Download or read book Search for the Third generation Scalar Leptoquarks and Heavy Right handed Neutrinos in Final States with Two Tau Leptons and Two Jets in Proton proton Collisions at sqrt s written by and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A search is performed for third-generation scalar leptoquarks and heavy right-handed neutrinos in events containing one electron or muon, one hadronically decaying tau lepton, and at least two jets, using a $\sqrt{s}$=13 TeV pp collision data sample corresponding to an integrated luminosity of 12.9 inverse femtobarns collected with the CMS detector at the LHC in 2016. The number of observed events is found to be in agreement with the standard model prediction. A limit is set at 95% confidence level on the product of the leptoquark pair production cross section and beta squared where beta is the branching fraction of leptoquark decay to a tau lepton and a bottom quark. Assuming beta=1, third-generation leptoquarks with masses below 850 GeV are excluded at 95 % confidence level. An additional search based on the same event topology involves heavy right-handed neutrinos, N[R], and right-handed W bosons, W[R], arising in a left-right symmetric extension of the standard model. In this search, W[R] bosons are assumed to decay to a tau lepton and N[R] followed by the decay of the N[R] to a tau lepton and an off-shell W[R] boson. Assuming the mass of the right-handed neutrino to be half of the mass of the right-handed W boson, W[R] boson masses below 2.9 TeV are excluded at 95 % confidence level. These results improve on the limits from previous searches for third-generation leptoquarks and heavy right-handed neutrinos with tau leptons in the final state.