Inclusive Search for New Physics with Like-Sign Dilepton Events in pp [over¯] Collisions at sqrt [s]= 1.96 TeV (original) (raw)
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Inclusive Search for New Physics with Like-Sign Dilepton Events in pp¯ Collisions at s=1.96 TeV
Physical Review Letters, 2007
We describe a search for anomalous production of events with two leptons (e or ) of the same electric charge in p p collisions at a center-of-mass energy of 1.96 TeV. Many extensions to the standard model predict the production of two leptons of the same electric charge. This search has a significant increase in sensitivity compared to earlier searches. Using a data sample corresponding to 1 fb ÿ1 of integrated luminosity recorded by the CDF II detector, we observe no significant excess in an inclusive selection (expect 33:2 4:7 events, observe 44) or in a supersymmetry-optimized selection (expect 7:8 1:1 events, observe 13.)
Physical review letters, 2004
We report on a search for anomalous production of events with at least two charged, isolated, likesign leptons, each with pT> 11 GeV= c using a 107 pbÿ1 sample of 1.8 TeV pp collisions collected by the CDF detector. We define a signal region containing low background from standard model processes. To avoid bias, we fix the final cuts before examining the event yield in the signal region using control regions to test the Monte Carlo predictions. We observe no events in the signal region, consistent with an expectation of 0 ...
Physical Review Letters, 2004
We report on a search for anomalous production of events with at least two charged, isolated, like-sign leptons with p T > 11 GeV/c using a 107 pb −1 sample of 1.8 TeV pp collisions collected by the CDF detector. We define a signal region containing low background from Standard Model processes. To avoid bias, we fix the final cuts before examining the event yield in the signal region using control regions to test the Monte Carlo predictions. We observe no events in the signal region, consistent with an expectation of 0.63 +0.84 −0.07 events. We present 95% confidence level limits on new physics processes in both a signature-based context as well as within a representative minimal supergravity (tan β = 3) model.
Physical Review D, 2007
We present results of a search at CDF in 929 56 pb ÿ1 of p p collisions at 1.96 TeV for the anomalous production of events containing a high-transverse momentum charged lepton (', either e or) and photon (), accompanied by missing transverse energy (E 6 T), and/or additional leptons and photons, and jets (X). We use the same selection criteria as in a previous CDF Run I search, but with an order-magnitude larger data set, a higher p p collision energy, and the CDF II detector. We find 163 'E 6 T X events, compared to an expectation of 150:6 13:0 events. We observe 74 '' X events, compared to an expectation of 65:1 7:7 events. We find no events similar to the Run I eeE 6 T event.
Search for New Physics in High p_ {T} Like-Sign Dilepton Events at CDF II
2011
We present a search for new physics in events with two high pT leptons of the same electric charge, using data with an integrated luminosity of 6: 1 fb À1. The observed data are consistent with standard model predictions. We set 95% CL lower limits on the mass of doubly charged scalars decaying to likesign dileptons, mHÆÆ> 190–245 GeV= c2, assuming 100% BR to ee, or e.
Search for anomalous production of multilepton events in pp collisions at sqrt {s}= 7 TeV
Journal of High …, 2012
The user has requested enhancement of the downloaded file. arXiv:0706.4448v1 [hep-ex] We report a search for the anomalous production of events with multiple charged leptons in pp 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. We 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 (χ 0 1 ) and chargino (χ ± 1 ) particles. For one particular choice of model parameters, the limits are M (χ 0 1 )>110 GeV/c 2 and M (χ ± 1 )>203 GeV/c 2 at 95% confidence level; the variation of these mass limits with model parameters is presented.
Search for new physics in lepton+photon+X events with 929 pb-1 of pp¯ collisions at s=1.96 TeV
Physical Review D, 2007
We present results of a search at CDF in 929 ± 56 pb −1 of pp collisions at 1.96 TeV for the anomalous production of events containing a high-transverse momentum charged lepton (ℓ, either e or µ) and photon (γ), accompanied by missing transverse energy ( E T ), and/or additional leptons and photons, and jets (X). We use the same selection criteria as in a previous CDF Run I search, but with an order-magnitude larger data set, a higher pp collision energy, and the CDF II detector. We find 163 ℓγ E T + X events, compared to an expectation of 150.6 ± 13.0 events. We observe 74 ℓℓγ + X events, compared to an expectation of 65.1 ± 7.7 events. We find no events similar to the Run I eeγγ E T event.
2011
A search is presented for physics beyond the standard model (SM) in final states with opposite-sign isolated lepton pairs accompanied by hadronic jets and missing transverse energy. The search is performed using LHC data recorded with the CMS detector, corresponding to an integrated luminosity of 34 pb −1 . No evidence for an event yield beyond SM expectations is found. An upper limit on the non-SM contribution to the signal region is deduced from the results. This limit is interpreted in the context of the constrained minimal supersymmetric model. Additional information is provided to allow testing the exclusion of specific models of physics beyond the SM.