Download or read book Search for New Physics with Same sign Isolated Dilepton Events with Jets and Missing Transverse Energy at the LHC written by and published by . This book was released on 2011 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results of searches for new physics in events with two same-sign isolated leptons, hadronic jets, and missing transverse energy in the final state are presented. The searches use an integrated luminosity of 35 inverse picobarns of pp collision data at a centre-of-mass energy of 7 TeV collected by the CMS experiment at the LHC. The observed numbers of events agree with the standard model predictions, and no evidence for new physics is found. To facilitate the interpretation of our data in a broader range of new physics scenarios, information on our event selection, detector response, and efficiencies is provided.

Download or read book Search for New Physics in Same Sign Dilepton Events in the CMS Detector at the Large Hadron Collider written by Lana Muniz and published by . This book was released on 2014 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: CMS results of a new physics search in same-sign dilepton events with b-tagged jets and missing transverse energy (MET) are being presented. These results cover the full 2012 dataset from the LHC at root(s)=8 TeV, corresponding to 19.5/fb. Isolated same-sign dilepton events are easily detected and rare in the Standard Model (SM), but they occur in abundance in some supersymmetry (SUSY) models. Hence, this channel provides a very clean, low background, search for new physics. Multiple search regions defined by the observables MET, hadronic energy (HT), and number of b-tagged jets are considered. The data agrees with the SM prediction, therefore exclusion limits at 95% C.L. are presented for various simplified SUSY models.

Download or read book Search for New Physics in Same sign Dilepton Events in Proton proton Collisions at u221A s written by and published by . This book was released on 2016 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for new physics is performed using events with two isolated same-sign leptons, two or more jets, and missing transverse momentum. The results are based on a sample of proton-proton collisions at a center-of-mass energy of 13 TeV recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 2.3 fb1. Multiple search regions are defined by classifying events in terms of missing transverse momentum, the scalar sum of jet transverse momenta, the transverse mass associated with a W boson candidate, the number of jets, the number of b quark jets, and the transverse momenta of the leptons in the event. The analysis is sensitive to a wide variety of possible signals beyond the standard model. No excess above the standard model background expectation is observed. Constraints are set on various supersymmetric models, with gluinos and bottom squarks excluded for masses up to 1300 and 680 GeV, respectively, at the 95% confidence level. Upper limits on the cross sections for the production of two top quark-antiquark pairs (119 fb) and two same-sign top quarks (1.7 pb) are also obtained. Furthermore, selection efficiencies and model independent limits are provided to allow further interpretations of the results.

Download or read book Search for New Physics in Events with Same sign Dileptons and Jets in Pp Collisions at sqrt s written by and published by . This book was released on 2014 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for new physics is performed based on events with jets and a pair of isolated, same-sign leptons. The results are obtained using a sample of proton-proton collision data collected by the CMS experiment at a centre-of-mass energy of 8 TeV at the LHC, corresponding to an integrated luminosity of 19.5 inverse femtobarns. In order to be sensitive to a wide variety of possible signals beyond the standard model, multiple search regions defined by the missing transverse energy, the hadronic energy, the number of jets and b-quark jets, and the transverse momenta of the leptons in the events are considered. No excess above the standard model background expectation is observed and constraints are set on a number of models for new physics, as well as on the same-sign top-quark pair and quadruple-top-quark production cross sections. As a result, information on event selection efficiencies is also provided, so that the results can be used to confront an even broader class of new physics models.

Download or read book Search for New Physics in a Final State with Same Sign Dileptons Jets and Missing Transverse Energy at 7 TeV Center of Mass Energy written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on a search for new physics in a final state with two same sign leptons, missing transverse energy, and significant hadronic activity at a center of mass energy $\sqrt{s}$ = 7 TeV. The data were collected with the CMS detector at the CERN LHC and correspond to an integrated luminosity of 0.98 $\mathrm{fb}^{-1}$. Data--driven methods are developed to estimate the dominant Standard Model backgrounds. No evidence for new physics is observed. The dominant background to the analysis comes from failures of lepton identification in Standard Model $t\bar{t}$ events. The $t\bar{t}$ production cross section in the dilepton final state is measured using 3.1 $\mathrm{fb}^{-1}$ of data. The cross section is measured to be 194 $\pm$ 72 (stat) $\pm$ 24 (syst) $\pm$ 21 (lumi) pb. An algorithm is developed that uses tracking information to improve the reconstruction of missing transverse energy. The reconstruction of missing transverse energy is commissioned using the first collisio ns recorded at 0.9, 2.36 and 7 TeV data. Events with abnormally large values of missing transverse energy are identified as arising from anomalous signals in the calorimeters. Tools are developed to identify and remove these anomalous signals.

Download or read book A Search for New Physics in Events with Oppositely Charged Dileptons Jets and Missing Transverse Energy in Proton proton Collisions at 7 TeV Center of Mass Energy written by Derek Michael Barge and published by . This book was released on 2014 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search is presented for physics beyond the standard model (BSM) in final states with a pair of opposite-sign isolated leptons accompanied by jets and missing transverse energy. The search uses LHC data recorded at a center-of-mass energy of 7 TeV with the CMS detector, corresponding to an integrated luminosity of approximately 5 inverse femto-barns. The search strategy probes models of dilepton production with heavy, colored objects that decay to final states including invisible particles, leading to very large hadronic activity and missing transverse energy. No evidence for an event yield in excess of the standard model expectations is found. Upper limits on the BSM contributions to the signal regions are deduced from the results, which are used to exclude a region of the parameter space of the constrained minimal supersymmetric extension of the standard model. Additional information related to detector efficiencies and response is provided to allow testing specific models of BSM physics not explicitly considered.

Download or read book Journeys Through The Precision Frontier Amplitudes For Colliders Tasi 2014 Proceedings Of The 2014 Theoretical Advanced Study Institute In Elementary Particle Physics written by Lance Dixon and published by World Scientific. This book was released on 2015-09-17 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is a compilation of the lectures at TASI 2014. The coverage focuses on modern calculational techniques for scattering amplitudes, and on the phenomenology of QCD in hadronic collisions. Introductions to flavor physics, dark matter, and physics beyond the Standard Model are also provided. The lectures are accessible to graduate students at the initial stages of their research careers.

Download or read book XXIII DAE High Energy Physics Symposium written by Prafulla Kumar Behera and published by Springer Nature. This book was released on 2021-05-18 with total page 1143 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents the peer-reviewed proceedings of the XXIII DAE-BRNS High Energy Physics Symposium 2018, which was held at the Indian Institute of Technology Madras, India, on 10-15 December 2018. Gathering selected contributions, the book highlights the latest developments and research trends in physics, detectors and instrumentation relevant to all branches of particle physics, astroparticle physics and closely related fields. The major topics covered include Standard Model physics, beyond Standard Model physics, neutrino physics, cosmology, formal theory, heavy ion physics & quantum chromodynamics (QCD), particle detectors and future experiments. Given the range of topics discussed, the book will be useful for beginners as well as advanced researchers in the field.

Download or read book Search for Physics Beyond the Standard Model in Opposite Sign Dilepton Events at Sqrt s written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A search is presented for physics beyond the standard model (SM) in final states with opposite-sign isolated lepton pairs accompanied by hadronic jets and missing transverse energy. The search is performed using LHC data recorded with the CMS detector, corresponding to an integrated luminosity of 34 inverse picobarns. No evidence for an event yield beyond SM expectations is found. An upper limit on the non-SM contribution to the signal region is deduced from the results. This limit is interpreted in the context of the constrained minimal supersymmetric model. Additional information is provided to allow testing the exclusion of specific models of physics beyond the SM.

Download or read book Electroweak Physics at the Large Hadron Collider with the ATLAS Detector written by Elodie Resseguie and published by Springer Nature. This book was released on 2020-11-03 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis discusses searches for electroweakly produced supersymmetric partners of the gauge and the Higgs bosons (gauginos and higgsinos) decaying to multiple leptons, using pp collisions at sqrt(s) = 13 TeV. The thesis presents an in-depth study of multiple searches, as well as the first 13 TeV cross section measurement for the dominant background in these searches, WZ production. Two searches were performed using 36.1/fb of data: the gaugino search, which makes use of a novel kinematic variable, and the higgsino search, which produced the first higgsino limits at the LHC. A search using 139/fb of data makes use of a new technique developed in this thesis to cross check an excess of data above the background expectation in a search using a Recursive Jigsaw Reconstruction technique. None of the searches showed a significant excess of data, and limits were expanded with respect to previous results. These searches will benefit from the addition of luminosity during HL-LHC; however, the current detector will not be able to withstand the increase in radiation. Electronics for the detector upgrade are tested and irradiated to ensure their performance.

Download or read book Search for New Physics in Events with Same Sign Leptons and Missing Energy with ATLAS at LHC written by Otilia-Anamaria Ducu and published by . This book was released on 2015 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the presented studies only the data recorded with the ATLAS detector is analyzed. The theoretical framework, the LHC collider and the ATLAS experiment are given in the first part of this thesis.At hadron colliders, the lepton identification and reconstruction are crucial for precise SM cross sections and coupling measurements or for new physics searches. Therefore, the second part of my thesis is dedicated to performance studies : in-situ measurements of electron identification and reconstruction efficiencies. The search for new physics is presented in the third part of the thesis. For these studies the channel with two same~- sign leptons and missing transverse energy is considered. The results are obtained with $L$~=~20 fb$^{-1}$ of data recorded at $sqrt s$ = 8 TeV and with the very first data at $sqrt s$ = 13 TeV. At the end of Run-1 no significant excess in data over the Standard Model prediction is observed and stringent limits on the supersymmetric particle masses are set. With the two same - sign leptons and jets final state it is also possible to measure directly the top quark Yukawa coupling using the ttbar + $H$ channel. This coupling is the largest in the Standard Model and it connects two of the heaviest particles predicted by the Standard Model, the top quark and the Higgs boson. In the fourth part of this thesis, a complete optimization is performed to reach the highest sensitivity for this signal in the two same~- sign leptons channel at $sqrt s$ = 13 TeV with 100 fb$^{-1}$ of data, corresponding to the end of Run-2.

Download or read book Phenomena Beyond the Standard Model What Do We Expect for New Physics to Look Like written by Roman Pasechnik and published by Frontiers Media SA. This book was released on 2020-09-03 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.

Download or read book Search for Supersymmetry at the LHC in Events with Jets and Missing Transverse Energy written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Search for New Physics in Events with High Jet Multiplicity and Low Missing Transverse Momentum in Proton proton Collisions at sqrt s written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A dedicated search is presented for new phenomena in inclusive eight- and ten-jet final states with low missing transverse momentum, with and without identification of jets originating from b quarks. The analysis is based on data from proton-proton collisions corresponding to an integrated luminosity of 19.6 inverse femtobarns collected with the CMS detector at the LHC at sqrt(s) = 8 TeV. The dominant multijet background expectations are obtained from low jet multiplicity control samples. Data agree well with the standard model background predictions, and limits are set in several benchmark models. Colorons (axigluons) with masses between 0.6 and 0.75 (up to 1.15) TeV are excluded at 95% confidence level. Similar exclusion limits for gluinos in R-parity violating supersymmetric scenarios are from 0.6 up to 1.1TeV. These results comprise the first experimental probe of the coloron and axigluon models in multijet final states.

Download or read book Search for New Physics in Mono jet Final States in pp Collisions written by Giuliano Gustavino and published by Springer. This book was released on 2017-06-19 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis provides a detailed and comprehensive description of the search for New Physics at the Large Hadron Collider (LHC) in the mono-jet final state, using the first 3.2 fb-1 of data collected at the centre of mass energy of colliding protons of 13~TeV recorded in the ATLAS experiment at LHC. The results are interpreted as limits in different theoretical contexts such as compressed supersymmetric models, theories that foresee extra-spatial dimensions and in the dark matter scenario. In the latter the limits are then compared with those obtained by other ATLAS analyses and by experiments based on completely different experimental techniques, highlighting the role of the mono-jet results in the context of dark matter searches.Lastly, a set of possible analysis improvements are proposed to reduce the main uncertainties that affect the signal region and to increase the discovery potential by further exploiting the information on the final state.

Download or read book Searching for SUSY in Events with Jets and Missing Transverse Energy Using alpha T with the CMS Detector at the LHC written by Zoe Hatherell and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Search for Diphoton Events with Missing Transverse Energy with the ATLAS Detector at the LHC written by Andrea Michelle Bangert and published by . This book was released on 2011 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: