Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Search For New Physics With Long Lived Particles Decaying To Photons And Missing Energy In Pp Collisions At A Center Of Mass Energy Of 7 Tev With The Cms Experiment At The Lhc
Download Search For New Physics With Long Lived Particles Decaying To Photons And Missing Energy In Pp Collisions At A Center Of Mass Energy Of 7 Tev With The Cms Experiment At The Lhc full books in PDF, epub, and Kindle. Read online Search For New Physics With Long Lived Particles Decaying To Photons And Missing Energy In Pp Collisions At A Center Of Mass Energy Of 7 Tev With The Cms Experiment At The Lhc ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Search for New Physics with Long-lived Particles Decaying to Photons and Missing Energy in Pp Collisions at a Center-of-mass Energy of 7 TeV with the CMS Experiment at the LHC by : Hongliang Liu
Download or read book Search for New Physics with Long-lived Particles Decaying to Photons and Missing Energy in Pp Collisions at a Center-of-mass Energy of 7 TeV with the CMS Experiment at the LHC written by Hongliang Liu and published by . This book was released on 2011 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: We perform a search for long-lived neutral particles decaying into a photon and invisible particles in pp collisions at a center-of-mass energy of 7 TeV at the Large Hadron Collider. In the context of gauge mediated supersymmetry with the lightest neutralino as the next-to-lightest supersymmetric particle and the gravitino as the lightest supersymmetric particle, the neutralino can decay into a gravitino and a photon with a non-zero lifetime. The impact parameter of the photon relative to the beam-beam collision point can be reconstructed using converted photons. The method is sensitive to lifetimes of the order of [Special characters omitted.] (0.1 ns). The data sample corresponds to an integrated luminosity of 2.1 ± 0.1 fb -1 recorded in the first part of 2011 by the CMS experiment at the LHC at [Special characters omitted.] = 7 TeV. The search is performed using events containing photons, missing transverse energy and jets. Upper limits at the 95% confidence level are presented on the cross section for such particles from pair-production, each of which decays into a photon and invisible particles.
Book Synopsis Search for New Physics in Pp Collisions at 7 TeV Center-of-mass Energy Using Diphoton Events with Large Missing Transverse Energy in the CMS Experiment at the LHC by : Robert Wayne Stringer
Download or read book Search for New Physics in Pp Collisions at 7 TeV Center-of-mass Energy Using Diphoton Events with Large Missing Transverse Energy in the CMS Experiment at the LHC written by Robert Wayne Stringer and published by . This book was released on 2011 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many theoretical models of physics beyond the Standard Model provide a signature of two photons and large missing transverse energy [Special characters omitted.] in the final state. This search was performed using 36 pb[superscript -1] of proton-proton collision data at [Squared root of s] = 7 TeV. The candidate events are determined by comparing the [Special characters omitted.] distribution for events with two photons and at least one hadronic jet with the [Special characters omitted.] T distribution from QCD and electroweak processes that have no true missing transverse energy. 1.2 ± 0.8 background events were expected, with one event observed. This result was interpreted in two theoretical models beyond the Standard Model. The cross section for General Gauge Mediated Supersymmetry Breaking is given an upper limit between 0.3 pb and 1.1 pb. Universal Extra Dimensions has been excluded for all values of 1/ R
Book Synopsis A Search for Long-lived Particles that Stop in the CMS Detector and Decay to Muons by :
Download or read book A Search for Long-lived Particles that Stop in the CMS Detector and Decay to Muons written by and published by . This book was released on 2016 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for long-lived particles that are produced in proton-proton collisions at the CERN LHC, come to rest in the CMS detector, and decay to muons is presented. The decays of the stopped particles could be observed during the intervals between LHC beam crossings, at times that are well separated from any proton-proton collisions. The analysis uses 19.7 1/fb of 8 TeV data collected by CMS in 2012, during a search interval of 293 hours of trigger livetime. Massive, long-lived particles do not exist in the Standard Model, and so any sign of them would be an indication of new physics. The results are interpreted with a model that predicts a long-lived particle that has a charge of twice the electron charge and that behaves like a lepton. Cross section limits are set for each long-lived particle mass as a function of lifetime, for lifetimes between 100 ns and 10 days. These are the first limits for long-lived stopped particles that decay to muons.
Book Synopsis Search for Long-lived Particles Using Delayed Photons in Proton-proton Collisions at 13 TeV with the CMS Detector by : Kevin Patrick McDermott
Download or read book Search for Long-lived Particles Using Delayed Photons in Proton-proton Collisions at 13 TeV with the CMS Detector written by Kevin Patrick McDermott and published by . This book was released on 2019 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents a search for long-lived particles using delayed photons in proton-proton collisions at sqrt(s) = 13 TeV recorded by the Compact Muon Solenoid (CMS) experiment at the CERN Large Hadron Collider in 2017, corresponding to an integrated luminosity of 41.5 fb^-1. This analysis includes a number of unique components that will be discussed: a dedicated signal trigger, out-of-time photon reconstruction and identification, and a detector time resolution measurement. The results of this search include the combination of a related analysis using data collected in 2016 also at sqrt(s) = 13 TeV, corresponding to a combined integrated luminosity of 77.4 fb^-1. The combined results are interpreted in the context of supersymmetry with gauge-mediated supersymmetry breaking, where the neutralino is long-lived and decays to a photon and a gravitino. Limits are presented as a function of the neutralino proper decay length and mass. For neutralino proper decay lengths of 10^1, 10^2, 10^3, and 10^4 cm, masses up to 320, 525, 360, and 215 GeV are excluded at 95% confidence level, respectively. Additionally, a discussion on a high-performance computing upgrade to CMS, known as mkFit, will be presented. mkFit is an on-going effort to exploit highly parallel computer architectures in vectorizing and parallelizing combinatorial Kalman filter charged particle track reconstruction algorithms. The current physics and computational performance of this project will be discussed.
Book Synopsis Search for Decays of Stopped Long-lived Particles Produced in Proton-proton Collisions at $\sqrt{s} by :
Download or read book Search for Decays of Stopped Long-lived Particles Produced in Proton-proton Collisions at $\sqrt{s} written by and published by . This book was released on 2015 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search has been performed for long-lived particles that could have come to rest within the CMS detector, using the time intervals between LHC beam crossings. The existence of such particles could be deduced from observation of their decays via energy deposits in the CMS calorimeter appearing at times that are well separated from any proton-proton collisions. Using a data set corresponding to an integrated luminosity of 18.6 fb-1 of 8 TeV proton-proton collisions, and a search interval corresponding to 281 h of trigger livetime, 10 events are observed, with a background prediction of 13.2+3.6 -2.5 events. Limits are presented at 95 % confidence level on gluino and top squark production, for over 13 orders of magnitude in the mean proper lifetime of the stopped particle. Assuming a cloud model of R-hadron interactions, a gluino with mass ≤1000 GeV and a top squark with mass ≤525 GeV are excluded, for lifetimes between 1 μs and 1000 s. Finally, these results are the most stringent constraints on stopped particles to date.
Book Synopsis Search for New Physics in the Exclusive Delayed ?+E(t) Final State in Pp Collisions at {u221A}(S) by :
Download or read book Search for New Physics in the Exclusive Delayed ?+E(t) Final State in Pp Collisions at {u221A}(S) written by and published by . This book was released on 2012 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents a search for heavy, long-lived, neutral particles that decay to photons in proton anti-proton collisions with a center of mass energy of 1.96 TeV at the Collider Detector at Fermilab (CDF) experiment. Such particles are typical of models of Gauge Mediated Supersymmetry Breaking (GMSB). We select events with a single photon, missing transverse energy, and little other activity in the detector. We model the photon arrival time for Standard Model and non-collision sources using a data-driven method and consider photons which have a time of arrival at the detector which is significantly delayed relative to predictions. Using 6.3 fb-1 of data collected from December 2004 to June 2010, we observe 322 events in the signal region compared to a background prediction of 287 ± 24 events. While the data are consistently above predictions, we report a model excess with a significance of 1.2 standard deviations from the null hypothesis.
Book Synopsis A Search for Displaced Leptons in the ATLAS Detector by : Lesya Horyn
Download or read book A Search for Displaced Leptons in the ATLAS Detector written by Lesya Horyn and published by Springer Nature. This book was released on 2022-02-07 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a search for long-lived particles decaying into displaced electrons and/or muons with large impact parameters. This signature provides unique sensitivity to the production of theoretical lepton-partners, sleptons. These particles are a feature of supersymmetric theories, which seek to address unanswered questions in nature. The signature searched for in this thesis is difficult to identify, and in fact, this is the first time it has been probed at the Large Hadron Collider (LHC). It covers a long-standing gap in coverage of possible new physics signatures. This thesis describes the special reconstruction and identification algorithms used to select leptons with large impact parameters and the details of the background estimation. The results are consistent with background, so limits on slepton masses and lifetimes in this model are calculated at 95% CL, drastically improving on the previous best limits from the Large Electron Positron Collider (LEP).
Book Synopsis Search for Heavy, Long-lived Particles that Decay to Photons in $p \bar{p}$ Collisions at $\sqrt{s}$ by :
Download or read book Search for Heavy, Long-lived Particles that Decay to Photons in $p \bar{p}$ Collisions at $\sqrt{s}$ written by and published by . This book was released on 2007 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents the results of the first search for heavy, neutral, longlived particles that decay to photons at a hadron collider. We use a sample of +jet+missing transverse energy events in $p \bar{p}$ collisions at √s = 1.96 TeV taken with the Collider Detector at Fermilab. Candidate events are selected based on the arrival time of a high-energy photon at the electromagnetic calorimeter as measured with a timing system that was recently installed. The final result is that we find 2 events, using 570±34 pb-1 of data collected during 2004-2005 at the Fermilab Tevatron, consistent with the background estimate of 1.3±0.7 events. While our search strategy does not rely on model-specific dynamics, we interpret this result in terms of cross section limits in a supersymmetric model with $\vec{X}$$0\atop{1}$ eG and set a world-best e 01 mass reach of 101 GeV/c2 at e = 5 ns. We can exclude any [gamma]+jet+missing transverse energy signal that would produce more than 5.5 events.
Book Synopsis The Late Light Show with Long-Lived Particles by : Kiley Elizabeth Kennedy
Download or read book The Late Light Show with Long-Lived Particles written by Kiley Elizabeth Kennedy and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Standard Model of particle physics constitutes the most accurate and comprehensive known description of the fundamental building blocks of the universe. However, overwhelming evidence suggests that the theory is incomplete and that new physics may be hiding at the TeV-scale. The Large Hadron Collider (LHC) at CERN probes these high-energy scales, opening a potential gateway to access physics beyond the Standard Model (BSM). Long-lived particles (LLPs) arise in many promising BSM theories, but they remain weakly constrained at the LHC. This thesis presents a novel search for displaced and delayed diphoton and dielectron vertices originating from the decay of a neutral LLP. The analysis uses the full LHC Run 2 dataset of pp collisions at a center-of-mass energy of √s = 13 TeV recorded by the ATLAS detector, corresponding to an integrated luminosity of 139 fb-1. The search harnesses the capabilities of the ATLAS Liquid Argon calorimeter to precisely measure the displacement and delay of the final state electromagnetic objects.
Book Synopsis Search for New Physics in the Exclusive Gamma+MET Final State in P-pbar Collisions at Sqrt(s) by : Adam Jude Aurisano
Download or read book Search for New Physics in the Exclusive Gamma+MET Final State in P-pbar Collisions at Sqrt(s) written by Adam Jude Aurisano and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents a search for heavy, long-lived, neutral particles that decay to photons in proton anti-proton collisions with a center of mass energy of 1.96 TeV at the Collider Detector at Fermilab (CDF) experiment. Such particles are typical of models of Gauge Mediated Supersymmetry Breaking (GMSB). We select events with a single photon, missing transverse energy, and little other activity in the detector. We model the photon arrival time for Standard Model and non-collision sources using a data-driven method and consider photons which have a time of arrival at the detector which is significantly delayed relative to predictions. Using 6.3 fb-1 of data collected from December 2004 to June 2010, we observe 322 events in the signal region compared to a background prediction of 287 ± 24 events. While the data are consistently above predictions, we report a model excess with a significance of 1.2 standard deviations from the null hypothesis. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/148427
Book Synopsis Search for Stopped Long-lived Particles Produced in Pp Collisions at 8 TeV at CMS by : Marissa L. Rodenburg
Download or read book Search for Stopped Long-lived Particles Produced in Pp Collisions at 8 TeV at CMS written by Marissa L. Rodenburg and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: At the Large Hadron Collider counter-rotating proton beams are collided at sqrt(s) = 8 TeV. The Compact Muon Solenoid (CMS) is used to measure the energies and charges of the resulting cascade of particles produced in these collisions. This search focuses on the observation of massive, long-lived particles, such as the gluino, that would suggest new physics beyond the Standard Model. A custom trigger is used to probe time periods during which no proton collisions occur, thereby eliminating most backgrounds to the signal. The remaining backgrounds resulting from cosmic rays, beam-related effects, and instrumental noise, are further reduced using a series of sophisticated selection cuts. Candidate events passing all selection cuts are analyzed using a counting experiment and limits are placed on the cross sections and masses of the gluino and the supersymmetric top quark.
Book Synopsis Particle Physics Reference Library by : Herwig Schopper
Download or read book Particle Physics Reference Library written by Herwig Schopper and published by Springer Nature. This book was released on 2020 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first open access volume of the handbook series contains articles on the standard model of particle physics, both from the theoretical and experimental perspective. It also covers related topics, such as heavy-ion physics, neutrino physics and searches for new physics beyond the standard model. A joint CERN-Springer initiative, the "Particle Physics Reference Library" provides revised and updated contributions based on previously published material in the well-known Landolt-Boernstein series on particle physics, accelerators and detectors (volumes 21A, B1,B2,C), which took stock of the field approximately one decade ago. Central to this new initiative is publication under full open access
Book Synopsis The Large Hadron Collider by : Lyndon R. Evans
Download or read book The Large Hadron Collider written by Lyndon R. Evans and published by EPFL Press. This book was released on 2009-01-01 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describes the technology and engineering of the Large Hadron collider (LHC), one of the greatest scientific marvels of this young 21st century. This book traces the feat of its construction, written by the head scientists involved, placed into the context of the scientific goals and principles.
Book Synopsis Search for Long-lived Particles that Decay Into Final States Containing Two Electrons Or Two Muons in Proton-proton Collisions at $\sqrt{s} by :
Download or read book Search for Long-lived Particles that Decay Into Final States Containing Two Electrons Or Two Muons in Proton-proton Collisions at $\sqrt{s} written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A search is performed for long-lived particles that decay into final states that include a pair of electrons or a pair of muons. The experimental signature is a distinctive topology consisting of a pair of charged leptons originating from a displaced secondary vertex. Events corresponding to an integrated luminosity of 19.6 (20.5) fb-1 in the electron (muon) channel were collected with the CMS detector at the CERN LHC in proton-proton collisions at √s=8 TeV. No significant excess is observed above standard model expectations. Upper limits on the product of the cross section and branching fraction of such a signal are presented as a function of the long-lived particle's mean proper decay length. The limits are presented in an approximately model-independent way, allowing them to be applied to a wide class of models yielding the above topology. Over much of the investigated parameter space, the limits obtained are the most stringent to date. In the specific case of a model in which a Higgs boson in the mass range 125-1000 GeV/c2 decays into a pair of long-lived neutral bosons in the mass range 20-350 GeV/c2, each of which can then decay to dileptons, the upper limits obtained are typically in the range 0.2-10 fb for mean proper decay lengths of the long-lived particles in the range 0.01-100 cm. In the case of the lowest Higgs mass considered (125 GeV/c2), the limits are in the range 2-50 fb. As a result, these limits are sensitive to Higgs boson branching fractions as low as 10-4.
Download or read book Displaced Vertices written by Dan Quach and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report the results of a search for long-lived particles produced in pairs in proton-proton collisions at the LHC operating at a center-of-mass energy of √s = 13 TeV. The data were collected by the CMS detector during the full Run 2 data taking period from 2015 through 2018, corresponding to a total integrated luminosity of 140/fb. This search targets pair-produced long-lived particles with a mean proper decay length between 0.1 and 100 mm that each decay into at least two quarks. The signature is a pair of displaced vertices each formed from many tracks. This search extends a previous CMS search using the 2015 and 2016 dataset, with improvements in background rejection, background estimation techniques, as well as uncertainty estimation. Results are compared with R-parity violating supersymmetry models that predict pair-produced long-lived particles, each decaying into multijet or dijet final states. No events are observed with two reconstructed high-track-multiplicity vertices. For models of long-lived pair-produced neutralinos, gluinos, and top squarks, pair-production cross sections larger than 0.08 fb at 95% confidence level are excluded for masses between 800 and 3000 GeV and mean proper decay lengths between 1 and 25 mm. In the gluino model, masses up to 2500 GeV are excluded for mean proper decay lengths between 0.6 and 90 mm. In the neutralino model, masses up to 1100 GeV are excluded for mean proper decay lengths between 0.6 and 70 mm. For the top squark model, masses up to 1600 GeV are excluded for mean proper decay lengths between 0.4 and 80 mm.
Book Synopsis Search for Long-lived Neutral Particles Decaying to Quark-antiquark Pairs in Proton-proton Collisions at {u221A}s by :
Download or read book Search for Long-lived Neutral Particles Decaying to Quark-antiquark Pairs in Proton-proton Collisions at {u221A}s written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A search is performed for long-lived massive neutral particles decaying to quark-antiquark pairs. The experimental signature is a distinctive topology of a pair of jets, originating at a secondary vertex. Events were collected with the CMS detector at the CERN LHC in proton-proton collisions at a center-of-mass energy of 8 TeV. The data analyzed correspond to an integrated luminosity of 18.5 fb–1. No significant excess is observed above standard model expectations. Upper limits at 95% confidence level are set on the production cross section of a heavy neutral scalar particle, H, in the mass range of 200 to 1000 GeV, decaying promptly into a pair of long-lived neutral X particles in the mass range of 50 to 350 GeV, each in turn decaying into a quark-antiquark pair. For X with mean proper decay lengths of 0.4 to 200 cm, the upper limits are typically 0.5–200 fb. The results are also interpreted in the context of an R-parity-violating supersymmetric model with long-lived neutralinos decaying into a quark-antiquark pair and a muon. For pair production of squarks that promptly decay to neutralinos with mean proper decay lengths of 2–40 cm, the upper limits on the cross section are typically 0.5–3 fb. As a result, the above limits are the most stringent on these channels to date.
Book Synopsis Strange Particle Production in Pp Collisions at Sqrt(s) by :
Download or read book Strange Particle Production in Pp Collisions at Sqrt(s) written by and published by . This book was released on 2011 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: The spectra of strange hadrons are measured in proton-proton collisions, recorded by the CMS experiment at the CERN LHC, at centre-of-mass energies of 0.9 and 7 TeV. The K0_s, Lambda, and Xi-̂ particles and their antiparticles are reconstructed from their decay topologies and the production rates are measured as functions of rapidity and transverse momentum. The results are compared to other experiments and to predictions of the PYTHIA Monte Carlo program. The transverse momentum distributions are found to differ substantially from the PYTHIA results and the production rates exceed the predictions by up to a factor of three.
