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 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 Search for Leptoquarks in Jet Topolgy with Missing Transverse Energy Using the D0 Detector written by Alexandre Zabi and published by . This book was released on 2004 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: The D0 experiment, located at the Fermilab National Accelerator Laboratory in the US, is used to study proton-anti-proton collisions at a center of mass energy of 1.96 TeV. The experiment's data acquisition system is based on a sophisticated trigger system used to select potentially interesting events. The Level 2 Silicon Track Trigger (L2STT) is part of the trigger system that provides precise reconstruction of charged particle tracks allowing the selection of events that contain the decays of long lived particles. For example, such particles appear in the decay of the Higgs boson into a pair of bottom quarks. The design of the L2STT preprocessor has greatly benefited from recent advances in electronics technology. The preprocessor has been recently installed and will be used to further optimize the triggering strategy of the experiment. Leptoquarks would mediate hypothetical new interactions between the quarks and leptons of the Standard Model. The existence of such particles would be evidence for physics beyond that model. In this thesis, a direct search for leptoquarks is performed in the jets and missing transverse energy final state. For this analysis, a trigger had to be developed along with a tool to precisely determine its efficiency. An analysis of events exhibiting the acoplanar jets topology was performed on a data sample corresponding to an integrated luminosity of 85 pb{sup -1}. This analysis has resulted in the determination of an exclusion region on the possible masses of leptoquarks ranging from 85 GeV/c{sup 2} to 109 GeV/c{sup 2} at the 95% confidence level.

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 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 Scalar Leptoquarks in the Acoplanar Jet Topology 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: A search for leptoquarks has been performed in 310 pb−1 of data from p{bar p} collisions at a center-of-mass energy of 1.96 TeV, collected by the D0 detector at the Fermilab Tevatron Collider. The topology analyzed consists of acoplanar jets with missing transverse energy. The data show good agreement with standard model expectations, and a lower mass limit of 136 GeV has been set at the 95% C.L. for a scalar leptoquark decaying exclusively into a quark and a neutrino.

Download or read book Search for Scalar Leptoquarks in the Acoplanar Jet Topology in P Anti p Collisions at S written by and published by . This book was released on 2006 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for leptoquarks has been performed in 310 pb−1 of data from p{bar p} collisions at a center-of-mass energy of 1.96 TeV, collected by the D0 detector at the Fermilab Tevatron Collider. The topology analyzed consists of acoplanar jets with missing transverse energy. The data show good agreement with standard model expectations, and a lower mass limit of 136 GeV has been set at the 95% C.L. for a scalar leptoquark decaying exclusively into a quark and a neutrino.

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 First Generation Leptoquark Pair Production in the Electron Missing Energy Jets Final State written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a search for the pair production of first generation scalar leptoquarks (LQ) in data corresponding to an integrated luminosity of 5.4 fb-1 collected with the D0 detector at the Fermilab Tevatron Collider in pp collisions at √s = 1.96 TeV. In the channel LQLQ → eq?eq, where q,q are u or d quarks, no significant excess of data over background is observed, and we set a 95% C.L. lower limit of 326 GeV on the leptoquark mass, assuming equal probabilities of leptoquark decays to eq and ?subesubq.

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 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 Search for Pair Production of First generation Leptoquarks in P Pbar Collisions at Sqrt s written by and published by . This book was released on 2009 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for pair production of first-generation leptoquarks (LQ) is performed with data collected by the D0 experiment in p{bar p} collisions at √s = 1.96 TeV at the Fermilab Tevatron Collider. In a sample of data corresponding to ≈ 1 fb−1 the search has been performed on the final states with two electrons and two jets or one electron, two jets and missing transverse energy. We find our data consistent with standard model expectations. The results are combined with those found in a previous analysis of events with two jets and missing transverse energy to obtain scalar LQ mass limits. We set 95% C.L. lower limits on a scalar LQ mass of 299 GeV, 284 GeV and 216 GeV for [beta] = 1, [beta] = 0.5 and [beta] = 0.02 respectively, where [beta] is the LQ branching ratio in the eq channel. This improves the results obtained with a lower luminosity sample from Run II of the Tevatron. Lower limits on vector LQ masses with different couplings from 357 GeV to 464 GeV for [beta] = 0.5 are also set using this analysis.

Download or read book Events with Large Missing Transverse Energy at the CERN Proton Antiproton Collider written by Mohammad M. Mohammadi and published by . This book was released on 1987 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Search for First Generation Scalar Leptoquarks at radical 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 Fragmentation of Quark and Gluon Jets in Proton antiproton Collisions at Center of mass Energy of 1 8 TeV written by Alexandre P. Pronko and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: We report the first model independent measurement of charged particle multiplicities in quark and gluon jets, Nq_ and Ng_, produced at the Tevatron in proton-antiproton collisions with center-of-mass energy 1.8 TeV and recorded by the Collider Detector at Fermilab. The measurements are made for jets with average energies 41 and 53 GeV by counting charged particle tracks in cones with opening angle of thetac_=0.28, 0.36, and 0.47 rad around the jet axis. The corresponding jet hardness Q=Ej_et*thetac_ varies in the range from 12 GeV to 25 GeV. At Q=19.2 GeV, the ratio of multiplicities r=Ng_/Nq_ is found to be 1.64"0.17, where statistical and systematic uncertainties are added in quadrature. The results are in agreement with re-summed perturbative QCD calculations and are consistent with recent ee− measurements.

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.