Search for New Physics Using Acoplanar Lepton Pair Events in e+ e- Collisions at "the square root of"s = 183-208 GeV
Abstract
A selection of events containing two charged leptons and significant missing transverse momentum has been carried out using a total data sample of 680.4 pb-1 collected at e+e- centre of mass energies between 183 and 208 GeV. The observed numbers of events are consistent with the expectation from Standard Model processes, which come mostly from W+W- production where both W particles decay leptonically. These events have been used to carry out a search for the pair production of slepton-s, leptonically decaying charginos and charged Higgs particles. No evidence for new phenomena is apparent and model independent production cross section limits for the new particles are presented. For a 100% branching ratio for the decay [formula removed], where [formula removed] is the lightest neutralino, the following are excluded at 95% CL: right handed smuons with masses below 94.0 GeV for [formula removed] > 4 GeV and right handed staus with masses below 89.5 GeV for [formula removed] > 8 GeV. Right-handed selectrons are excluded at 95% CL for masses below 97.5 GeV for [formula removed] > 10 GeV, within the framework of the Minimal Supersymmetric Standard Model for micro < -100 GeV and tan beta = 1.5. Further comparisons between the data and Standard Model are presented, inspired by new physics scenarios which may lead to final states containing two charged leptons plus missing transverse momentum plus isolated photons, and also events containing two charged leptons with unequal momentum distributions plus missing transverse momentum. The data is found to be in agreement with the Standard Model expectation for both cases.
- Publication:
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Ph.D. Thesis
- Pub Date:
- 2002
- Bibcode:
- 2002PhDT.......265M
- Keywords:
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- Astrophysics;Physics