Download or read book Search for Z Bosons Decaying Into Tau Pairs in Pp Collisions at ra z Cuadrada S written by Carlos Felipe González Hernández and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: New heavy neutral gauge bosons, generically referred as Z0 bosons, are predicted in several theoretical scenarios beyond the standard model (BSM). In these kinds of scenarios, the breaking of extended symmetry usually results in an extra U(1)' symmetry group. This additional symmetry would give rise to the existence of a Z' boson with a mass that should be in the TeV scale. There are some scenarios that predict a generational coupling dependence, where the Z' boson would decay preferentially to the third generation of fermions, for instance, the topcolor-assisted technicolor (TAT) models. These scenarios are a motivation to search for Z' bosons decaying into tau pairs. The search for Z' decaying into tau-pairs involves four experimental signatures since the tau lepton can decay leptonically or hadronically. The dihadronic tau channel has the best sensitivity since it has the highest expected signal yield, but it has a high background contribution coming...
Download or read book A Search for Z Gauge Bosons Decaying to Tau antitau Pairs in Proton proton Collisions with the ATLAS Detector written by Andrew Gerard Leister and published by . This book was released on 2015 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for Top squark Pairs Decaying Into Higgs Or Z Bosons in Pp Collisions at arow written by and published by . This book was released on 2014 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for the Production of ZW and ZZ Boson Pairs Decaying Into Charged Leptons and Jets in Proton antiproton 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 present a measurement of the production cross section for ZW and ZZ boson pairs in final states with a pair of charged leptons, from the decay of a Z boson, and at least two jets, from the decay of a W or Z boson, using the full sample of proton-antiproton collisions recorded with the CDF II detector at the Tevatron, corresponding to 8.9 fb(̂-1) of integrated luminosity. We increase the sensitivity to vector boson decays into pairs of quarks using a neural network discriminant that exploits the differences between the spatial spread of energy depositions and charged-particle momenta contained within the jet of particles originating from quarks and gluons. Additionally, we employ new jet energy corrections to Monte Carlo simulations that account for differences in the observed energy scales for quark and gluon jets. The number of signal events is extracted through a simultaneous fit to the dijet mass spectrum in three classes of events: events likely to contain jets with a heavy-quark decay, events likely to contain jets originating from light quarks, and events that fail these identification criteria. We determine the production cross section to be 2.5 +2.0 -1.0 pb (
Download or read book Search for Neutral Resonances Decaying Into a Z Boson and a Pair of B Jets Or tau Leptons written by and published by . This book was released on 2016 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search is performed for a new resonance decaying into a lighter resonance and a Z boson. Two channels are studied, targeting the decay of the lighter resonance into either a pair of oppositely charged tau leptons or a b-bbar pair. The Z boson is identified via its decays to electrons or muons. The search exploits data collected by the CMS experiment at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.8 fb-1. Furthermore, no significant deviations are observed from the standard model expectation and limits are set on production cross sections and parameters of two-Higgs-doublet models.
Download or read book Heavy Neutral Particle Decays to Tau Pairs written by Michail Bachtis and published by Springer Science & Business Media. This book was released on 2013-12-13 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work presented in this thesis spans a wide range of experimental particle physics subjects, starting from level-1 trigger electronics to the final results of the search for Higgs boson decay and to tau lepton pairs. The thesis describes an innovative reconstruction algorithm for tau decays and details how it was instrumental in providing a measurement of Z decay to tau lepton pairs. The reliability of the analysis is fully established by this measurement before the Higgs boson decay to tau lepton pairs is considered. The work described here continues to serve as a model for analysing CMS Higgs to tau leptons measurements.
Download or read book Chaptong sani written by and published by . This book was released on 1920 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurements of Z and Z Production in Pp 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: The production of Z bosons with one or two isolated high-energy photons is studied using pp collisions at √s=8 TeV. The analyses use a data sample with an integrated luminosity of 20.3 fb-1 collected by the ATLAS detector during the 2012 LHC data taking. The Z? and Z?? production cross sections are measured with leptonic (e+e-, ?+?-, ?????????) decays of the Z boson, in extended fiducial regions defined in terms of the lepton and photon acceptance. They are then compared to cross-section predictions from the Standard Model, where the sources of the photons are radiation off initial-state quarks and radiative Z-boson decay to charged leptons, and from fragmentation of final-state quarks and gluons into photons. The yields of events with photon transverse energy ET > 250 GeV from l+l-? events and with ET > 400 GeV from ?????????? events are used to search for anomalous triple gauge-boson couplings ZZ? and Z??. The yields of events with diphoton invariant mass m?? > 200 GeV from l+l-?? events and with m?? > 300 GeV from ??????????? events are used to search for anomalous quartic gauge-boson couplings ZZ?? and Z???. As a result, no deviations from Standard Model predictions are observed and limits are placed on parameters used to describe anomalous triple and quartic gauge-boson couplings.
Download or read book Heavy Neutral Particle Decays to Tau Pairs in Proton Collisions at Sqrt s written by and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes a study of the tau-pair final state in proton collisions at a center of mass energy of 7 TeV using the CMS Experiment at the CERN Large Hadron Collider. Tau leptons usually decay to hadrons and their efficient detection is very challenging in a hadronic environment. A novel tau reconstruction algorithm that maintains tau detection efficiency for low background rates was developed. Events were then selected from the CMS 2011 data sample in three T T final states depending on the tau decays: mu + T (h), e+ T (h), e+mu where T (h) denotes a hadronic tau decay. Those events were used to measure the Z-boson production cross section where Z yields T T . A search for the Standard Model and Minimal Supersymmetric Standard Model (MSSM) Higgs bosons was also performed. No signal was observed in the Higgs search and stringent new bounds were set for the SM Higgs production and in the MSSM parameter space.
Download or read book A Search for Z Bosons in the Dimuon Decay Channel in 8 TeV Proton proton Collisions written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for Leptophobic Z Bosons Decaying Into Four lepton Final States in Proton proton Collisions at Sqrt s written by and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for heavy narrow resonances decaying into four-lepton final states from cascade decays of a Z' boson has been performed using proton-proton collision data at sqrt(s) = 8 TeV collected by the CMS experiment, corresponding to an integrated luminosity of 19.7 inverse femtobarns. No excess of events over the standard model background expectation is observed. Upper limits for a benchmark model on the product of cross section and branching fraction for the production of these heavy narrow resonances are presented. The limit excludes leptophobic Z' bosons with masses below 2.5 TeV within the benchmark model. This is the first result to constrain a leptophobic Z' resonance in the four-lepton channel.
Download or read book Search for Anomalous Couplings in the Decay of Polarized Z Bosons to Tau Lepton Pairs written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Using a sample of 4,500 polarized Z decays to[tau] lepton pairs accumulated with the SLD detector at the SLAC Linear Collider (SLC) in 1993-95, a search has been made for anomalous couplings in the neutral current reaction e[sup+]e[sup[minus]][yields][tau][sup+][tau][sup[minus]]. A measurement of the CP violating Weak Electric Dipole Moment (WEDM) and the CP conserving Weak Magnetic Dipole Moment (WMDM) of the[tau] lepton has been performed by considering the transverse spin polarization of[tau] leptons produced at the Z pole. Using a maximum likelihood technique, the observed[tau] decay spectra in the e, [mu], [pi], and[rho] decay channels are used to infer the net transverse polarization of the underlying tau leptons, and a fit for the anomalous dipole moments is performed. No evidence for these dipole movements is observed, and limits are placed on both the real and imaginary parts of the WEDM and WMDM.
Download or read book Search for Particles Decaying Into a Z Boson and a Photon in P Anti p Collisions at S 1 2 written by and published by . This book was released on 2006 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present the results of the first search for a new particle X produced in p{bar p} collisions at √s = 1.96 TeV and subsequently decaying to Z[gamma]. The search uses 0.3 fb−1 of data collected with the D0 detector at the Fermilab Tevatron Collider. They set limits on the production cross section times the branching fraction [sigma](p{bar p} → X) x B(X → Z[gamma]) that range from 0.4-3.5 pb at the 95% C.L. for X with invariant masses between 100 and 1000 GeV/c2 over a wide range of X decay widths.
Download or read book Search for Anomalous Couplings in the Decay of Polarized Z Bosons to Tau Lepton Pairs written by Eric Charles Torrence and published by . This book was released on 1997 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for Z Decaying to Ttbar in the Dilepton jets Final States with the CMS Detector at S written by Jimin George and published by . This book was released on 2015 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: A model-independent search for heavy resonances decaying to top-antitop pairs using 19. 7fb8́21 of data recorded by the CMS detector in pp collisions at 8 TeV center of mass energy is presented. The search is based on events containing two leptons (electron or muon) and at least two jets. No deviation is observed over the expected rate from the Standard Model processes. Therefore, 95% confidence-level upper limits are set on the production cross section times branching fraction for the heavy resonances decaying to top-antitop in the mass range of 1-3 TeV. Upper mass limits are set for the narrow and wide width leptophobic top color Z', as well as for the Kaluza-Klein excitation of gluons as predicted in theories beyond the Standard Model.
Download or read book Search for Massive Neutral Gauge Bosons Decaying Into Muon Pairs in Pp Collisions at s written by Noam Tal Hod and published by . This book was released on 2013 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for High mass Resonances Decaying Into ZZ in P bar p Collisions at sqrt s written by and published by . This book was released on 2011 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors search for high-mass resonances decaying into Z boson pairs using data corresponding to 6 fb−1 collected by the CDF experiment in p{bar p} collisions at √s = 1.96 TeV. The search is performed in three distinct final states: ZZ → ll−l+l−, ZZ → l+l−??, and ZZ → l+l−jj. For a Randall-Sundrum graviton G*, the 95% CL upper limits on the production cross section times branching ratio to ZZ,?(p{bar p} → G* → ZZ), vary between 0.26 pb and 0.045 pb in the mass range 300
