Download or read book Search for Anomalous Production of Events with a Photon Jet B quark Jet and Missing Transverse Energy written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a signature-based search for anomalous production of events containing a photon, two jets, of which at least one is identified as originating from a b quark, and missing transverse energy (/E{sub T}). The search uses data corresponding to 2.0 fb−1 of integrated luminosity from p{bar p} collisions at a center-of-mass energy of √s = 1.96 TeV, collected with the CDF II detector at the Fermilab Tevatron. From 6,697,466 events with a photon candidate with transverse energy ET > 25 GeV, we find 617 events with /E{sub T} > 25 GeV and two or more jets with E{sub T} > 15 GeV, at least one identified as originating from a b quark, versus an expectation of 607 ± 113 events. Increasing the requirement on /E{sub T} to 50 GeV, we find 28 events versus an expectation of 30 ± 11 events. We find no indications of non-standard-model phenomena.
Download or read book Search for Anomalous Production of Photon Jets Missing Transverse Energy in Proton antiproton Collisions at a Center of Mass Energy of 1 96 TeV Using the CDF II Detector written by Samantha K. Hewamanage and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A model-independent signature-based search for physics beyond the Standard Model is performed in the photon + jets + missing transverse energy channel in proton-antiproton collisions at a center of mass energy of 1.96 TeV using the CDF II detector. Events with a photon + jets are predicted by the Standard Model and also by many theoretical models beyond the Standard Model. In the Standard Model, the main mechanisms for photon + jets production include quark-antiquark annihilation and quark-gluon scattering. No intrinsic missing transverse energy is present in any of these Standard Model processes. In this search, photon + [greater-than or equal to] 1 jet and photon + [greater-than or equal to] 2 jet events are analyzed with and without a minimum requirement on the missing transverse energy. Numerous mass distributions and kinematic distributions are studied and no significant excess over the background prediction is found. All results indicate good agreement with expectations of the Standard Model.
Download or read book Search for Anomalous Production of Photon B jet and Missing Transverse Energy at CDF written by and published by . This book was released on 2008 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for Anomalous Single Top Quark Production in Association with a Photon in Pp Collisions at u221A s written by and published by . This book was released on 2016 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: We found the results of a search for flavor changing neutral currents (FCNC) through single top quark production in association with a photon is presented. The study is based on proton-proton collisions at a center-of-mass energy of 8 TeV using data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.8 fb-1. The search for t? events where t → Wb andW → ?n is conducted in final states with a muon, a photon, at least one hadronic jet with at most one being consistent with originating from a bottom quark, and missing transverse momentum. Furthermore, there was no evidence of single top quark production in association with a photon through a FCNC is observed. Upper limits at the 95% confidence level are set on the tug and tcg anomalous couplings and translated into upper limits on the branching fraction of the FCNC top quark decays: B(t → u?) 1.3 x 10sup-4/sup and B(t →c?) 1.7 x 10
Download or read book Search for Anomalous Production of Events with Two Photons and Additional Energetic Objects at CDF written by and published by . This book was released on 2009 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present results of a search for anomalous production of two photons together with an electron, muon, [tau] lepton, missing transverse energy, or jets using p{bar p} collision data from 1.1-2.0 fb−1 of integrated luminosity collected by the Collider Detector at Fermilab (CDF). The event yields and kinematic distributions are examined for signs for new physics without favoring a specific model of new physics. The results are consistent with the standard model expectations. The search employs several new analysis techniques that significantly reduce instrumental backgrounds in channels with an electron and missing transverse energy.
Download or read book Search for Events with Leptonic Jets and Missing Transverse Energy in mathbf p bar p Collisions at mathbf sqrt s written by and published by . This book was released on 2010 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the first search for pair production of isolated jets of charged leptons in association with a large imbalance in transverse energy in p{bar p} collisions using 5.8 fb−1 of integrated luminosity collected by the D0 detector at the Fermilab Tevatron Collider. No excess is observed above Standard Model background, and the result is used to set upper limits on the production cross section of pairs of supersymmetric chargino and neutralino particles as a function of 'dark-photon' mass, where the dark photon is produced in the decay of the lightest supersymmetric particle.
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 Searching the Inclusive Lepton Photon Missing E T B quark Signature for Radiative Top Quark Decay and Non Standard Model Processes written by and published by . This book was released on 2009 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a search for new phenomena in a signature suppressed in the standard model of elementary particles (SM), we compare the inclusive production of events containing a lepton (l), a photon ([gamma]), significant transverse momentum imbalance (E{sub T}), and a jet identified as containing a b-quark, to SM predictions. The search uses data produced in proton-antiproton collisions at √s = 1.96 TeV corresponding to 1.9 fb−1 of integrated luminosity taken with the CDF detector at the Fermilab Tevatron. We find 28 l[gamma]bE{sub T} events versus an expectation of 31.0{sub -3.5}{sup +4.1} events. If we further require events to contain at least three jets and large total transverse energy, simulations predict that the largest SM source is top-quark pair production with an additional radiated photon, t{bar t} + [gamma]. In the data we observe 16 t{bar t}[gamma] candidate events versus an expectation from non-top-quark SM sources of 11.2{sub -2.1}{sup +2.3}. Assuming the difference between the observed number and the predicted non-top-quark total is due to SM top quark production, we estimate the t{bar t} cross section to be 0.15 ± 0.08 pb.
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 W to T B in Events with Large Missing Transverse Energy and Jets with the CDF Detector at the Fermilab Tevatron Collider written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the scope of the strong ongoing data analysis efforts of the CDF col- laboration at Fermilab, we present a search for the production of mas sive W1 bosons decaying to a top and a bottom quark in p$\bar{p}$ collisions at √s = 1.96 TeV. To perform this search, we select events with large Missing Transverse Energy plus two or three jets, in which the W generated from top decays leptonically, and either the e or μ is lost or the [tau] is reconstructed as a jet. A complete study of the selected sample is discussed, including the creation and subsequent optimization of a Neural Network-based multivariate tool to reject the QCD multijet background from the signal region. Finally, we perform a likelihood-based multichannel Bayesian fit procedure on the invariant transverse mass of the Missing Transverse Energy and jets to extract 95% CL limits on [sigma](p$\bar{p}$ . → W') × B(W' → tb) for MW' = 200 GeV/c2.
Download or read book Search for New Phenomena in Events with a Photon and Missing Transverse Momentum in math Display written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of a search for new phenomena in events with an energetic photon and large missing transverse momentum with the ATLAS experiment at the LHC are reported. Data were collected in proton-proton collisions at a center-of-mass energy of 8 TeV and correspond to an integrated luminosity of 20.3 fb-1. The observed data are well described by the expected Standard Model backgrounds. The expected (observed) upper limit on the fiducial cross section for the production of events with a photon and large missing transverse momentum is 6.1 (5.3) fb at 95% confidence level. The exclusion limits are presented on models of new phenomena with large extra spatial dimensions, supersymmetric quarks, and direct pair production of dark-matter candidates.
Download or read book Search for Large Extra Dimensions in Final States Containing One Photon Or Jet and Large Missing Transverse Energy Produced in P Anti p Collisions at S 1 2 written by and published by . This book was released on 2008 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present the results of searches for large extra dimensions in samples of events with large missing transverse energy E{sub T} and either a photon or a jet produced in p{bar p} collisions at √s = 1.96 TeV collected with the CDF II detector. For [gamma] + E{sub T} and jet + E{sub T} candidate samples corresponding to 2.0 fb−1 and 1.1 fb−1 of integrated luminosity respectively, they observe good agreement with standard model expectations and obtain a combined lower limit on the fundamental parameter of the large extra dimensions model, M{sub D}, as a function of the number of extra dimensions in the model.
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.
Download or read book Search for New Physics in the Jets Missing ET Topology written by and published by . This book was released on 2006 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although the standard model of particle physics agrees perfectly with experimental data, it is unlikely the final theory describing particles and their interactions. New phenomena has been searched in the jets and missing transverse energy topology. Such phenomena may be due to the pair production of leptoquarks decaying into a quark and a neutrino or the pair production of stops decaying into a charm and a neutralino which is assumed to be the lightest supersymmetric particle. These searches have been performed with the D0 detector at hadronic collider TeVatron with a center of mass energy of 1.96 TeV. This kind of search needs a good understanding of the jet energy calibration. The determination of the relative jet energy scale has allowed them to reduce the systematic uncertainties on the jet energy measurement when comparing the data and the simulation. Moreover a new method has been developed in order to correct simulated jets for the differences observed in the jet energy scale, the jet energy resolution and the jet reconstruction efficiency between the data and the simulation. The data analysis, performed with an integrated luminosity of 310 pb−1, has not observed any excess. This result is interpreted in terms of limit on the mass of the particles: leptoquarks with a mass smaller than 136 GeV and stops with a mass smaller than 131 GeV, for a neutralino mass equal to 46 GeV, are excluded with 95% confidence level.
Download or read book High Energy Physics written by Hesheng Chen and published by World Scientific. This book was released on 2005-05-03 with total page 1424 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 32nd International Conference on High Energy Physics belongs to the Rochester Conference Series, and is the most important international conference in 2004 on high energy physics. The proceedings provide a comprehensive review on the recent developments in experimental and theoretical particle physics. The latest results on Top, Higgs search, CP violation, neutrino mixing, pentaquarks, heavy quark mesons and baryons, search for new particles and new phenomena, String theory, Extra dimension, Black hole and Lattice calculation are discussed extensively. The topics covered include not only those of main interest to the high energy physics community, but also recent research and future plans. Contents: Neutrino Masses and MixingsQuark Matter and Heavy Ion CollisionsParticle Astrophysics and CosmologyElectroweak PhysicsQCD Hard InteractionsQCD Soft InteractionsComputational Quantum Field TheoryCP Violation, Rare Kaon Decay and CKMR&D for Future Accelerator and DetectorHadron Spectroscopy and ExoticsHeavy Quark Mesons and BaryonsBeyond the Standard ModelString Theory Readership: Experimental and theoretical physicists and graduate students in the fields of particle physics, nuclear physics, astrophysics and cosmology.Keywords:High Energy Physics;Particle Physics;Electroweak;QCD;Heavy Quark;Neutrino;Particle Astrophysics;Hadron Spectroscopy;CP Violation;Quark Matter;Future Accelerator
Download or read book Search for a Dijet Resonance in Events with Jets and Missing Transverse Energy in Pp over Collisions at Sqrt s written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on a search for a dijet resonance in events with only two or three jets and large imbalance in the total event transverse momentum. This search is sensitive to the possible production of a new particle in association with a W or Z boson, where the boson decays leptonically with one or more neutrinos in the final state. We use the full data set collected by the CDF II detector at the Tevatron collider at a proton-antiproton center-of-mass energy of 1.96 TeV. These data correspond to an integrated luminosity of 9.1 fb{̂-1}. We study the invariant mass distribution of the two jets with highest transverse energy. We find good agreement between data and standard model background expectations and measure the combined cross section for WW, WZ, and ZZ production to be 13.8{̂+3.0}_{-2.7} pb. No significant anomalies are observed in the mass spectrum and 95% credibility level upper limits are set on the production rates of a potential new particle in association with a W or Z boson.
Download or read book Search for New Phenomena in Final States with Large Jet Multiplicities and Missing Transverse Momentum with ATLAS Using written by and published by . This book was released on 2016 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results are reported of a search for new phenomena, such as supersymmetric particle production, that could be observed in high-energy proton–proton collisions. Events with large numbers of jets, together with missing transverse momentum from unobserved particles, are selected. The data analysed were recorded by the ATLAS experiment during 2015 using the 13 TeV centre-of-mass proton–proton collisions at the Large Hadron Collider, and correspond to an integrated luminosity of 3.2 fb-1. The search selected events with various jet multiplicities from ≥7 to ≥10 jets, and with various b-jet multiplicity requirements to enhance sensitivity. Furthermore, no excess above Standard Model expectations is observed. The results are interpreted within two supersymmetry models, where gluino masses up to 1400 GeV are excluded at 95% confidence level, significantly extending previous limits.
