Search for Anomalous Production of Multi-lepton Events in P Anti-p Collisions at S**1/2 PDF Download
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Languages : en
Pages : 7
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The authors report a search for the anomalous production of events with multiple charged leptons in p{bar p} collisions at √s = 1.96 TeV using a data sample corresponding to an integrated luminosity of 346 pb−1 collected by the CDF II detector at the Fermilab Tevatron. The search is divided into three-lepton and four-or-more-lepton data samples. They observe six events in the three-lepton sample and zero events in the ≥4-lepton sample. Both numbers of events are consistent with standard model background expectations. Within the framework of an R-parity violating supergravity model, the results are interpreted as mass limits on the lightest neutralino ({bar {chi}}1°) and chargino ({bar {chi}}1{sup {+-}}) particles. For one particular choice of model parameters, the limits are M({bar {chi}}1°) > 110 GeV/c2 and M({bar {chi}}1{sup {+-}}) > 203 GeV/c2 at 95% confidence level; the variation of these mass limits with model parameters is presented.
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Category :
Languages : en
Pages : 7
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Book Description
The authors report a search for the anomalous production of events with multiple charged leptons in p{bar p} collisions at √s = 1.96 TeV using a data sample corresponding to an integrated luminosity of 346 pb−1 collected by the CDF II detector at the Fermilab Tevatron. The search is divided into three-lepton and four-or-more-lepton data samples. They observe six events in the three-lepton sample and zero events in the ≥4-lepton sample. Both numbers of events are consistent with standard model background expectations. Within the framework of an R-parity violating supergravity model, the results are interpreted as mass limits on the lightest neutralino ({bar {chi}}1°) and chargino ({bar {chi}}1{sup {+-}}) particles. For one particular choice of model parameters, the limits are M({bar {chi}}1°) > 110 GeV/c2 and M({bar {chi}}1{sup {+-}}) > 203 GeV/c2 at 95% confidence level; the variation of these mass limits with model parameters is presented.
Author:
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ISBN:
Category :
Languages : en
Pages : 7
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Book Description
The authors report a search for the anomalous production of events with multiple charged leptons in p{bar p} collisions at √s = 1.96 TeV using a data sample corresponding to an integrated luminosity of 346 pb−1 collected by the CDF II detector at the Fermilab Tevatron. The search is divided into three-lepton and four-or-more-lepton data samples. They observe six events in the three-lepton sample and zero events in the ≥4-lepton sample. Both numbers of events are consistent with standard model background expectations. Within the framework of an R-parity violating supergravity model, the results are interpreted as mass limits on the lightest neutralino ({bar {chi}}1°) and chargino ({bar {chi}}1{sup {+-}}) particles. For one particular choice of model parameters, the limits are M({bar {chi}}1°)> 110 GeV/c2 and M({bar {chi}}1{sup {+-}})> 203 GeV/c2 at 95% confidence level; the variation of these mass limits with model parameters is presented.
Author: Scott Wilbur
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ISBN: 9781267071606
Category :
Languages : en
Pages : 89
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Book Description
A search is presented for anomalous production of events containing multiple low-energy leptons produced in association with a W or Z boson using the Collider Detector at Fermilab. The leptons are not required to be isolated, and the signature is therefore sensitive to a wide range of so-called "lepton jet" topologies. The search uses data corresponding to 5.1 fb--1 of integrated luminosity from pp ̄ collisions at a center-of-mass energy of s = 1.96 TeV. The observed events are compared with the standard model predictions in bins of additional electron and muon multiplicity. No indications are found of phenomena beyond the standard model. A 95% confidence level limit is presented on the production cross section for an example benchmark point of a dark-matter inspired model of supersymmetric hidden valley Higgs production. Object identification efficiencies are also provided in order to enable the calculation of limits on additional models.
Author: A. Loginov
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ISBN:
Category :
Languages : en
Pages : 10
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Book Description
The authors present results of a search in 929 {+-} 56 pb{sup -1} of p{bar p} collisions at 1.96 TeV for the anomalous production of events containing a charged lepton ({ell}, either e or {mu}) and a photon ({gamma}), both with high transverse momentum, accompanied by additional signatures, X, including missing transverse energy (E{sub T}) and additional leptons and photons. They use the same selection criteria as in the previous CDF Run I search, but with an order-magnitude larger data set, a higher p{bar p} collision energy, and the CDF II detector.
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Category :
Languages : en
Pages : 8
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Book Description
The authors present results of a search for anomalous production of events containing a charged lepton (l, either e or [mu]) and a photon ([gamma]), both with high transverse momentum, accompanied by additional signatures, X, including missing transverse energy (E{sub T}) and additional leptons and photons. We use the same kinematic selection criteria as in a previous CDF search, but with a substantially larger data set, 305 pb−1, a p{bar p} collision energy of 1.96 TeV, and the upgraded CDF II detector. We find 42 l[gamma]E{sub T} events versus a standard model expectation of 37.3 ± 5.4 events. The level of excess observed in Run I, 16 events with an expectation of 7.6 ± 0.7 events (corresponding to a 2.7[sigma] effect), is not supported by the new data. In the signature of ll[gamma] + X we observe 31 events versus an expectation of 23.0 ± 2.7 events. In this sample we find no events with an extra photon or E{sub T} and so find no events like the one ee[gamma][gamma]E{sub T} event observed in Run I.
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Category :
Languages : en
Pages : 10
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Book Description
The authors present results of a search in 929 ± 56 pb−1 of p{bar p} collisions at 1.96 TeV for the anomalous production of events containing a charged lepton (l, either e or?) and a photon , both with high transverse momentum, accompanied by additional signatures, X, including missing transverse energy (E{sub T}) and additional leptons and photons. They use the same selection criteria as in the previous CDF Run I search, but with an order-magnitude larger data set, a higher p{bar p} collision energy, and the CDF II detector.
Author:
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Category :
Languages : en
Pages : 8
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Book Description
The authors present results of a search for anomalous production of events containing a charged lepton (l, either e or?) and a photon , both with high transverse momentum, accompanied by additional signatures, X, including missing transverse energy (E{sub T}) and additional leptons and photons. We use the same kinematic selection criteria as in a previous CDF search, but with a substantially larger data set, 305 pb−1, a p{bar p} collision energy of 1.96 TeV, and the upgraded CDF II detector. We find 42 l?E{sub T} events versus a standard model expectation of 37.3 ± 5.4 events. The level of excess observed in Run I, 16 events with an expectation of 7.6 ± 0.7 events (corresponding to a 2.7? effect), is not supported by the new data. In the signature of ll? + X we observe 31 events versus an expectation of 23.0 ± 2.7 events. In this sample we find no events with an extra photon or E{sub T} and so find no events like the one ee??E{sub T} event observed in Run I.
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Languages : en
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We present a search for anomalous production of the signature lepton + photon + b-quark + missing transverse energy (`[gamma]6ETb) produced in $p\bar{p}$ collisions at √ s = 1.96 TeV using 6.0 fb-1 of data taken with the CDF detector in Run II at the Tevatron. In addition to this signature-based search, we present a closely-related search for top pair production with an additional radiated photon, t$\bar{t}$[gamma]. We find 85 `[gamma]6ETb events versus an expectation of 99.1±9.3 events. High-statistics control samples are used to evaluate a low-energy photon [chi] 2 cut. Additionally requiring the events to contain at least three jets, have a total transverse energy of 200 GeV, and that the photon candidate passes the [chi] 2 cut, we observe 30 t$\bar{t}$[gamma] candidate events versus an expectation from non-top Standard Model (SM) sources of 13.0 ± 2.1 Assuming the difference between the observed number and the predicted non-top SM total is due to top production, we measure the tt$\bar{[gamma]}$ cross section to be 0.18 ± 0.08 pb. We also measure the ratio of the t$\bar{t}$[gamma] cross section to the t$\bar{t}$cross section to be 0.024 ± 0.009, which compares well with a SM prediction of 0.024 ± 0.013.
Author:
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Category :
Languages : en
Pages : 88
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Book Description
This paper presents a search for anomalous production of multiple low-energy leptons in association with a $W$ or $Z$ boson using events collected at the CDF experiment corresponding to $5.1$ fb${̂-1}$ of integrated luminosity. This search is sensitive to a wide range of topologies with low-momentum leptons, including those with the leptons near one another. The observed rates of production of additional electrons and muons are compared with the standard model predictions. No indications of phenomena beyond the standard model are found. A 95\% confidence level limit is presented on the production cross section for a benchmark model of supersymmetric hidden-valley Higgs production. Particle identification efficiencies are also provided to enable the calculation of limits on additional models.
![A Search for New Physics in Photon-lepton Events in Proton-antiproton Collisions At[radical] S PDF](https://books.google.com/books/content/images/frontcover/oRbAjwEACAAJ?fife=w80-h100)
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Languages : en
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Book Description
We present the results of a search in p[bar p] collisions at[radical]s= 1.8 TeV for anomalous production of events containing a photon with large transverse energy and a lepton (e or[mu]) with large transverse energy, using 86 pb[sup -1] of data collected at the Collider Detector at Fermilab during the 1994-95 collider run at the Fermilab Tevatron. The presence of large missing transverse energy (E[sub T]), additional photons, or additional leptons in these events is also analyzed. The results are consistent with standard model expectations, with the possible exception of photon-lepton events with large E[sub T], for which the probability of a statistical fluctuation of the standard model expectation up to and above the observed level is 0.7%.
