Search for Supersymmetry at the LHC in Events with Jets and Missing Transverse Energy

Search for Supersymmetry at the LHC in Events with Jets and Missing Transverse Energy
Author:
Publisher:
Total Pages:
Release: 2011
Genre:
ISBN:

Download Search for Supersymmetry at the LHC in Events with Jets and Missing Transverse Energy Book in PDF, Epub and Kindle

A search for events with jets and missing transverse energy is performed in a data sample of pp collisions collected at sqrt(s) = 7 TeV by the CMS experiment at the LHC. The analyzed data sample corresponds to an integrated luminosity of 1.14 inverse femtobarns. In this search, a kinematic variable, alphaT, is used as the main discriminator between events with genuine and misreconstructed missing transverse energy. No excess of events over the standard model expectation is found. Exclusion limits in the parameter space of the constrained minimal supersymmetric extension of the standard model are set. In this model, squark masses below 1.1 TeV are excluded at 95% CL. Gluino masses below 1.1 TeV are also ruled out at 95% CL for values of the universal scalar mass parameter below 500 GeV.

Search for Supersymmetry in Proton-proton Collisions at 7 TeV in Events with a Single Lepton, B-tagged Jets and Missing Transverse Momentum at the LHC Using Data Collected from the CMS Detector

Search for Supersymmetry in Proton-proton Collisions at 7 TeV in Events with a Single Lepton, B-tagged Jets and Missing Transverse Momentum at the LHC Using Data Collected from the CMS Detector
Author: Wing Howard To
Publisher:
Total Pages: 145
Release: 2013
Genre:
ISBN: 9781303052842

Download Search for Supersymmetry in Proton-proton Collisions at 7 TeV in Events with a Single Lepton, B-tagged Jets and Missing Transverse Momentum at the LHC Using Data Collected from the CMS Detector Book in PDF, Epub and Kindle

This thesis describes a search for supersymmetry (SUSY) at the Large Hadron Collider using data collected in Run 2011 at center of mass energy of 7 TeV by the Compact Muon Solenoid detector with an integrated luminosity of 4.98 $fb{-1}$. First, the Large Hadron Collider is briefly described along with the Compact Muon Solenoid detector. Second, the Standard Model of particle physics is described which leads to the motivations for supersymmetry and its description. Finally, a search for supersymmetry in events with a single lepton, 2 b-tagged jets and missing transverse energy is documented in detail. The results are used to predict the yields from the standard model in bins missing transverse energy (\met) and total transverse hadronic energy (HT). Limits are set using these results using a minimal supergravity SUSY model and simplified model spectra SUSY model.

Search for Supersymmetry in Events with B Jets and Missing Transverse Momentum at the LHC.

Search for Supersymmetry in Events with B Jets and Missing Transverse Momentum at the LHC.
Author:
Publisher:
Total Pages: 24
Release: 2011
Genre:
ISBN:

Download Search for Supersymmetry in Events with B Jets and Missing Transverse Momentum at the LHC. Book in PDF, Epub and Kindle

A search for supersymmetry is presented using a sample of events with b jets and missing transverse momentum. The search uses a data sample of proton-proton collisions at a centre-of-mass energy of 7 TeV, corresponding to an integrated luminosity of 35 inverse picobarns, collected with the CMS detector. A total of 0.33 +0.43 -0.33 (stat.) +/- 0.13 (syst.) events is predicted, using control samples in the data, to arise from standard model processes, and one event is observed in the data. Upper limits are set at the 95% confidence level on the cross sections of benchmark supersymmetric models.

Search for Supersymmetry in Pp Collisions at 7 TeV in Events with Jets and Missing Transverse Energy

Search for Supersymmetry in Pp Collisions at 7 TeV in Events with Jets and Missing Transverse Energy
Author:
Publisher:
Total Pages: 218
Release: 2011
Genre:
ISBN:

Download Search for Supersymmetry in Pp Collisions at 7 TeV in Events with Jets and Missing Transverse Energy Book in PDF, Epub and Kindle

A search for supersymmetry with R-parity conservation in proton-proton collisions at a centre-of-mass energy of 7 TeV is presented. The data correspond to an integrated luminosity of 35 inverse picobarns collected by the CMS experiment at the LHC. The search is performed in events with jets and significant missing transverse energy, characteristic of the decays of heavy, pair-produced squarks and gluinos. The primary background, from standard model multijet production, is reduced by several orders of magnitude to a negligible level by the application of a set of robust kinematic requirements. With this selection, the data are consistent with the standard model backgrounds, namely t t-bar, W + jet and Z + jet production, which are estimated from data control samples. Limits are set on the parameters of the constrained minimal supersymmetric extension of the standard model. These limits extend those set previously by experiments at the Tevatron and LEP colliders.

A Search for Supersymmetry in Events with Jets and Missing Momentum Using Data Collected by the CMS Detector at 13 TeV

A Search for Supersymmetry in Events with Jets and Missing Momentum Using Data Collected by the CMS Detector at 13 TeV
Author: Sam Daniel Mullin
Publisher:
Total Pages: 108
Release: 2016
Genre:
ISBN: 9781369146592

Download A Search for Supersymmetry in Events with Jets and Missing Momentum Using Data Collected by the CMS Detector at 13 TeV Book in PDF, Epub and Kindle

As successful as the Standard Model of particle physics has been it still has several major shortcomings which range from unanswered theoretical questions to a lack of any explanation for observed phenomena such as dark matter. One proposed theory for physics beyond the Standard Model which provides solutions for some of these issues is supersymmetry. This dissertation presents a search for supersymmetry using 2.3 fb -1 of proton-proton collision data. This data was collected at a center-of-mass energy of 13 TeV by the CMS detector at the LHC during 2015. This search focuses on top squark pair production where the produced stops both decay to an all hadronic final state. These decays are characterized by multiple jets and missing transverse momentum. A baseline search region is defined to be sensitive to signal processes which occur at rates many orders of magnitude lower than Standard Model processes. The sensitivity to various signal models is improved by dividing this baseline region into distinct categories. Events with an unreconstructed lepton from leptonic W boson decays constitute the primary background. There are also significant contributions from events where a Z boson decays invisibly to neutrinos especially in bins with higher missing transverse momentum. Events with multijet production where one jet has been severely mis-measured as well as those with a pair of top quarks and an invisibly decaying Z boson also have a small presence in the search region. The contributions from these processes to the search region is estimated using data control regions. No statistically significant deviations from the predicted background yields are observed. The results are interpreted in terms of exclusion limits using the Simplified Model Spectrum framework. Stop and neutralino masses are probed up to 780 GeV and 260 GeV respectively.

Predicted and Totally Unexpected in the Energy Frontier Opened by LHC

Predicted and Totally Unexpected in the Energy Frontier Opened by LHC
Author: Antonino Zichichi
Publisher: World Scientific
Total Pages: 685
Release: 2011
Genre: Science
ISBN: 9814340219

Download Predicted and Totally Unexpected in the Energy Frontier Opened by LHC Book in PDF, Epub and Kindle

Antonino Zichichi has contributed to Predicted and Totally Unexpected in the Energy Frontier Opened by Lhc as an editor.Zichichi-Univ of Bologna, Italy, Natl Inst of Nuclear Physics, Italy

Search for Supersymmetry in Events with Missing Transverse Energy and B-Jets with the ATLAS Detector

Search for Supersymmetry in Events with Missing Transverse Energy and B-Jets with the ATLAS Detector
Author: Stefan Winkelmann
Publisher:
Total Pages: 161
Release: 2012
Genre:
ISBN:

Download Search for Supersymmetry in Events with Missing Transverse Energy and B-Jets with the ATLAS Detector Book in PDF, Epub and Kindle

Zusammenfassung: In this thesis, searches for Supersymmetry (SUSY) with the ATLAS detector at the Large Hadron Collider (LHC) at a center-of-mass energy of 7 TeV are presented. The focus lies on two searches for squarks of the third generation, specifically the direct production of stop pairs and the production of stops via the decay of gluinos. The searches are based on experimental signatures with large missing transverse energy, b-quark jets and one electron or muon. The datasets used correspond to an integrated luminosity of 4.7 fb-1 and 2.05 fb-1, respectively. Inclusive observables, which are sensitive to the mass scale of SUSY particles are used to discriminate the signal from the Standard Model (SM) background processes. In both analyses, dedicated background estimation techniques are used. Control samples in data are used to supplement or replace the background estimation from Monte Carlo simulation. No significant excess beyond the SM expectation is found. Therefore, both model independent upper limits on physics beyond the SM are derived and model specific interpretations are given

Perspectives On Lhc Physics

Perspectives On Lhc Physics
Author: Gordon Kane
Publisher: World Scientific
Total Pages: 352
Release: 2008-06-27
Genre: Science
ISBN: 9814472190

Download Perspectives On Lhc Physics Book in PDF, Epub and Kindle

The Large Hadron Collider (LHC), located at CERN, Geneva, Switzerland, is the world's largest and highest energy and highest intensity particle accelerator. Here is a timely book with several perspectives on the hoped-for discoveries from the LHC.This book provides an overview on the techniques that will be crucial for finding new physics at the LHC, as well as perspectives on the importance and implications of the discoveries. Among the accomplished contributors to this book are leaders and visionaries in the field of particle physics beyond the Standard Model, including two Nobel Laureates (Steven Weinberg and Frank Wilczek), and presumably some future Nobel Laureates, plus top younger theorists and experimenters. With its blend of popular and technical contents, the book will have wide appeal, not only to physical scientists but also to those in related fields.

Search for Supersymmetry in Events with One Lepton and Multiple Jets in Proton-proton Collisions at Sqrt(s)

Search for Supersymmetry in Events with One Lepton and Multiple Jets in Proton-proton Collisions at Sqrt(s)
Author:
Publisher:
Total Pages:
Release: 2016
Genre:
ISBN:

Download Search for Supersymmetry in Events with One Lepton and Multiple Jets in Proton-proton Collisions at Sqrt(s) Book in PDF, Epub and Kindle

A search for supersymmetry is performed in events with a single electron or muon in proton-proton collisions at a center-of-mass energy of 13 TeV. The data were recorded by the CMS experiment at the LHC and correspond to an integrated luminosity of 2.3 inverse femtobarns. Several exclusive search regions are defined based on the number of jets and b-tagged jets, the scalar sum of the jet transverse momenta, and the scalar sum of the missing transverse momentum and the transverse momentum of the lepton. The observed event yields in data are consistent with the expected backgrounds from standard model processes. The results are interpreted using two simplified models of supersymmetric particle spectra, both of which describe gluino pair production. In the first model, each gluino decays via a three-body process to top quarks and a neutralino, which is associated with the observed missing transverse momentum in the event. Gluinos with masses up to 1.6 TeV are excluded for neutralino masses below 600 GeV. In the second model, each gluino decays via a three-body process to two light quarks and a chargino, which subsequently decays to a W boson and a neutralino. The mass of the chargino is taken to be midway between the gluino and neutralino masses. In this model, gluinos with masses below 1.4 TeV are excluded for neutralino masses below 700 GeV.