Search for new physics in the mumu+e/mu+EslashT channel with a low-pT lepton threshold at the Collider Detector at Fermilab

• Main Authors: Xie, Si (Contributor), Makhoul, K. (Contributor), Knuteson, Bruce O. (Contributor), Henderson, C. (Contributor), Hahn, Kristian Allan (Contributor), Gomez-Ceballos, Guillelmo (Contributor), Choudalakis, Georgios (Contributor), Bauer, Gerry P. (Contributor), Paus, Christoph M. E. (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Physics (Contributor), Massachusetts Institute of Technology. Laboratory for Nuclear Science (Contributor)
• Format: Article
• Language: English
• Published: American Physical Society, 2010-03-04T19:37:16Z.
• Subjects: Article
• Online Access: Get fulltext

A search for new physics using three-lepton (trilepton) data collected with the CDF II detector and corresponding to an integrated luminosity of 976 pb[superscript -1] is presented. The standard model predicts a low rate of trilepton events, which makes some supersymmetric processes, such as chargino-neutralino production, measurable in this channel. The μμ+ℓ signature is investigated, where ℓ is an electron or a muon, with the additional requirement of large missing transverse energy. In this analysis, the lepton transverse momenta with respect to the beam direction (p[subscript T]) are as low as 5  GeV/c, a selection that improves the sensitivity to particles that are light as well as to ones that result in leptonically decaying tau leptons. At the same time, this low-p[subscript T] selection presents additional challenges due to the non-negligible heavy-quark background at low lepton momenta. This background is measured with an innovative technique using experimental data. Several dimuon and trilepton control regions are investigated, and good agreement between experimental results and standard-model predictions is observed. In the signal region, we observe one three-muon event and expect 0.4±0.1 μμ+ℓ events from standard-model processes.
Academy of Finland
Slovak R&D Agency
Programa Consolider-Ingenio 2010, Spain
Ministerio de Ciencia e Innovación, Spain
Russian Foundation for Basic Research
Institut National de Physique Nucleaire et Physique des Particules/CNRS
Royal Society, United Kingdom
Science and Technology Facilities Council, United Kingdom
Korean Research Foundation
Korean Science and Engineering Foundation
Bundesministerium für Bildung und Forschung, Germany
Alfred P. Sloan Foundation
Swiss National Science Foundation
National Science Council of the Republic of China
Natural Sciences and Engineering Research Council of Canada
Ministry of Education, Culture, Sports, Science and Technology of Japan
Italian Istituto Nazionale di Fisica Nucleare
National Science Foundation
United States Department of Energy