Search for High-mass Diphoton Resonances in pp Collisions at {u221A}s

Search for High-mass Diphoton Resonances in pp Collisions at {u221A}s
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Release: 2015
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This article describes a search for high-mass resonances decaying to a pair of photons using a sample of 20.3 fb-1 of pp collisions at √s = 8 TeV recorded with the ATLAS detector at the Large Hadron Collider. The data are found to be in agreement with the Standard Model prediction, and limits are reported in the framework of the Randall-Sundrum model. This theory leads to the prediction of graviton states, the lightest of which could be observed at the Large Hadron Collider. A lower limit of 2.66 (1.41) TeV at 95% confidence level is set on the mass of the lightest graviton for couplings of k/M¯Pl = 0.1 (0.01).

Search for High-mass Diphoton Resonances in Proton-proton Collisions at 13 TeV and Combination with 8 TeV Search

Search for High-mass Diphoton Resonances in Proton-proton Collisions at 13 TeV and Combination with 8 TeV Search
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Release: 2016
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The results of a search are presented for the resonant production of high-mass photon pairs, specifically spin-0 and spin-2 resonances with an invariant mass between 0.5 and 4.5 TeV, and with a width, relative to the mass, between 1.4E-4 and 5.6E-2. The data sample corresponds to an integrated luminosity of 12.9 inverse femtobarns of proton-proton collisions collected with the CMS detector in 2016 at a center-of-mass energy of 13 TeV. No significant excess is observed relative to the standard model expectation. The results of the search are combined statistically with those previously obtained in 2012 and 2015 at sqrt(s)=8 and 13TeV, respectively, corresponding to integrated luminosities of 19.7 and 3.3 inverse femtobarns, to derive exclusion limits on scalar resonances produced through gluon-gluon fusion, and on Randall-Sundrum gravitons. The lower mass limits for Randall-Sundrum gravitons range from 1.95 to 4.45 TeV for coupling parameters between 0.01 and 0.2. These are the most stringent limits on Randall-Sundrum graviton production to date.

Search for Diphoton Resonances in the Mass Range from 150 to 850 GeV in Pp Collisions at $\sqrt{s}$

Search for Diphoton Resonances in the Mass Range from 150 to 850 GeV in Pp Collisions at $\sqrt{s}$
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Total Pages: 38
Release: 2015
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Results are presented of a search for heavy particles decaying into two photons. The analysis is based on a 19.7fb-1 sample of proton-proton collisions at $\sqrt{s}$ = 8 TeV collected with the CMS detector at the CERN LHC. The diphoton mass spectrum from 150 to 850 GeV is used to search for an excess of events over the background. The search is extended to new resonances with natural widths of up to 10% of the mass value. No evidence for new particle production is observed and limits at 95% confidence level on the production cross section times branching fraction to diphotons are determined. These limits are interpreted in terms of two-Higgs-doublet model parameters.

Search for New Resonances in W? and Z? Final States in Pp Collisions at {u221A} S

Search for New Resonances in W? and Z? Final States in Pp Collisions at {u221A} S
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Total Pages: 20
Release: 2014
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This Letter presents a search for new resonances decaying to final states with a vector boson produced in association with a high transverse momentum photon, V? , with V=W(→l?) or Z(→l+l-), where l=e or ?. The measurements use 20.3 fb-1 of proton–proton collision data at a center-of-mass energy of √s = 8 TeV recorded with the ATLAS detector. No deviations from the Standard Model expectations are found, and production cross section limits are set at 95% confidence level. Masses of the hypothetical aT and ?T states of a benchmark Low Scale Technicolor model are excluded in the ranges [275,960] GeV and [200,700]?[750,890] GeV, respectively. Limits at 95% confidence level on the production cross section of a singlet scalar resonance decaying to Z? final states have also been obtained for masses below 1180 GeV.

Search for High-mass Resonances Decaying to E? in P$\bar{p}$ Collisions at {u221A}s

Search for High-mass Resonances Decaying to E? in P$\bar{p}$ Collisions at {u221A}s
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Total Pages: 126
Release: 2006
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We describe a general search for resonances decaying to a neutral e? final state in p$\bar{p}$ collisions at a center-of-mass energy of 1.96 TeV. Using a data sample representing 344 pb-1 of integrated luminosity recorded by the CDF II experiment, we compare Standard Model predictions with the number of observed events for invariant masses between 50 and 800 GeV/c2. Finding no significant excess (5 events observed vs. 7.7 ± 0.8 expected for Msube? /sub” 100 GeV/csup2

Search for High Mass Photon Pairs in P[anti P] Collisions At[radical]

Search for High Mass Photon Pairs in P[anti P] Collisions At[radical]
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Release: 2001
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The authors present results of a search for diphoton resonances produced inclusively and in association with a vector boson using 100 pb[sup[minus]1] of p[anti p] collisions using the CDF detector. They set upper limits on the product of cross section times branching ratio for p[anti p][r-arrow][gamma][gamma][r-arrow] X and p[anti p][r-arrow][gamma][gamma][r-arrow] W/Z. Using a NLO prediction for associated production cross section of a Higgs with a vector boson (W or Z), they set an upper limit on the branching ratio for H[r-arrow][gamma][gamma]. They set a lower limit on the mass of a'bosophilic' Higgs boson (e.g. one which couples only to[gamma], W, and Z bosons with Standard Model couplings) of 82 GeV/c[sup 2] at 95% C.L.

Search for High Mass Photon Pairs in P{anti P} Collisions at √s

Search for High Mass Photon Pairs in P{anti P} Collisions at √s
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Total Pages: 10
Release: 1998
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The authors present results of a search for diphoton resonances produced inclusively and in association with a vector boson using 100 pb−1 of p{anti p} collisions using the CDF detector. They set upper limits on the product of cross section times branching ratio for p{anti p} →?? → X and p{anti p} →?? → W/Z. Using a NLO prediction for associated production cross section of a Higgs with a vector boson (W or Z), they set an upper limit on the branching ratio for H →??. They set a lower limit on the mass of a b̀osophilic ̀Higgs boson (e.g. one which couples only to?, W, and Z bosons with Standard Model couplings) of 82 GeV/c2 at 95% C.L.

Search for Heavy Lepton Resonances Decaying to a Z Boson and a Lepton in Pp Collisions at {u221A}s

Search for Heavy Lepton Resonances Decaying to a Z Boson and a Lepton in Pp Collisions at {u221A}s
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Release: 2015
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In this study, a search for heavy leptons decaying to a Z boson and an electron or a muon is presented. The search is based on pp collision data taken at √s=8 TeV by the ATLAS experiment at the CERN Large Hadron Collider, corresponding to an integrated luminosity of 20.3 fb−1. Three high-transverse-momentum electrons or muons are selected, with two of them required to be consistent with originating from a Z boson decay. No significant excess above Standard Model background predictions is observed, and 95% confidence level limits on the production cross section of high-mass trilepton resonances are derived. The results are interpreted in the context of vector-like lepton and type-III seesaw models. For the vector-like lepton model, most heavy lepton mass values in the range 114–176 GeV are excluded. For the type-III seesaw model, most mass values in the range 100–468 GeV are excluded.