Isolated electrons and muons in events with missing transverse momentum at HERA

Summary, in English

A search for events with a high-energy isolated electron or muon and missing transverse momentum has been performed at the electron-proton collider HERA using an integrated luminosity of 13.6 pb(-1) in e(-) p scattering and 104.7 pb(-1) in e(+) p scattering. Within the Standard Model such events are expected to be mainly due to W boson production with subsequent leptonic decay. In e(-) p interactions one event is observed in the electron channel and none in the muon channel, consistent with the expectation of the Standard Model. In the e(+) p data a total of 18 events are seen in the electron and muon channels compared to an expectation of 12.4 +/- 1.7 dominated by W production (9.4 +/- 1.6). Whilst the overall observed number of events is broadly in agreement with the number predicted by the Standard Model, there is-an excess of events with transverse momentum of the hadronic system greater than 25 GeV with 10 events found compared to 2.9 +/- 0.5 expected. The results are used to determine the cross-section for events with an isolated electron or muon and missing transverse momentum. (C) 2003 Published by Elsevier Science B.V.

• Author: V Andreev; B Andrieu; T Anthonis; A Astvatsatourov; A Babaev; J Bahr; P Baranov; E Barrelet; W Bartel; S Baumgartner; J Becker; M Beckingham; A Beglarian; O Behnke; A Belousov; C Berger; T Berndt; JC Bizot; J Bohme; V Boudry; J Bracinik; W Braunschweig; V Brisson; HB Broker; DP Brown; D Bruncko; FW Busser; A Bunyatyan; A Burrage; G Buschhorn; L Bystritskaya; AJ Campbell; S Caron; F Cassol-Brunner; V Chekelian; D Clarke; C Collard; JG Contreras; YR Coppens; JA Coughlan; MC Cousinou; BE Cox; G Cozzika; J Cvach; JB Dainton; WD Dau; K Daum; Mattias Davidsson; B Delcourt; N Delerue; R Demirchyan; A De Roeck; EA De Wolf; C Diaconu; J Dingfelder; P Dixon; V Dodonov; JD Dowell; A Dubak; C Duprel; G Eckerlin; D Eckstein; V Efremenko; S Egli; R Eichler; F Eisele; M Ellerbrock; E Elsen; M Erdmann; W Erdmann; PJW Faulkner; L Favart; A Fedotov; R Felst; J Ferencei; S Ferron; M Fleischer; P Fleischmann; YH Fleming; G Flucke; G Flugge; A Fomenko; I Foresti; J Formanek; G Franke; G Frising; E Gabathuler; K Gabathuler; J Garvey; J Gassner; J Gayler; R Gerhards; C Gerlich; S Ghazaryan; L Goerlich; N Gogitidze; S Gorbounov; C Grab; V Grabski; H Grassler; T Greenshaw; G Grindhammer; D Haidt; L Hajduk; J Haller; B Heinemann; G Heinzelmann; RCW Henderson; H Henschel; O Henshaw; R Heremans; G Herrera; I Herynek; M Hildebrandt; M Hilgers; KH Hiller; J Hladky; P Hoting; D Hoffmann; R Horisberger; A Hovhannisyan; M Ibbotson; C Issever; M Jacquet; M Jaffre; L Janauschek; X Janssen; V Jemanov; Leif Jönsson; C Johnson; DP Johnson; MAS Jones; Hannes Jung; D Kant; M Kapichine; Martin Karlsson; O Karschnick; J Katzy; F Keil; N Keller; J Kennedy; IR Kenyon; C Kiesling; P Kjellberg; M Klein; C Kleinwort; T Kluge; G Knies; B Koblitz; SD Kolya; V Korbel; P Kostka; R Koutouev; A Koutov; J Kroseberg; K Kruger; J Kueckens; T Kuhr; MPJ Landon; W Lange; T Lastovicka; P Laycock; A Lebedev; B Leissner; R Lemrani; V Lendermann; S Levonian; B List; E Lobodzinska; B Lobodzinski; N Loktionova; V Lubimov; S Luders; D Luke; L Lytkin; N Malden; E Malinovski; S Mangano; P Marage; J Marks; R Marshall; HU Martyn; J Martyniak; SJ Maxfield; D Meer; A Mehta; K Meier; AB Meyer; H Meyer; J Meyer; S Michine; S Mikocki; D Milstead; S Mohrdieck; MN Mondragon; F Moreau; A Morozov; JV Morris; K Muller; P Murin; V Nagovizin; B Naroska; J Naumann; T Naumann; PR Newman; F Niebergall; C Niebuhr; G Nowak; M Nozicka; B Olivier; JE Olsson; D Ozerov; V Panassik; C Pascaud; GD Patel; M Peez; E Perez; A Petrukhin; JP Phillips; D Pitzl; R Poschl; I Potachnikova; B Povh; J Rauschenberger; P Reimer; B Reisert; C Risler; E Rizvi; P Robmann; R Roosen; A Rostovtsev; S Rusakov; K Rybicki; DPC Sankey; E Sauvan; S Schatzel; J Scheins; FP Schilling; P Schleper; D Schmidt; D Schmidt; S Schmidt; S Schmitt; M Schneider; L Schoeffel; A Schoning; T Schorner-Sadenius; V Schroder; HC Schultz-Coulon; C Schwanenberger; K Sedlak; F Sefkow; I Sheviakov; LN Shtarkov; Y Sirois; T Sloan; P Smirnov; Y Soloviev; D South; V Spaskov; A Specka; H Spitzer; R Stamen; B Stella; J Stiewe; I Strauch; U Straumann; S Tchetchelnitski; G Thompson; PD Thompson; F Tomasz; D Traynor; P Truol; G Tsipolitis; I Tsurin; J Turnau; JE Turney; E Tzamariudaki; A Uraev; M Urban; A Usik; S Valkar; A Valkarova; C Vallee; P Van Mechelen; AV Trevino; S Vassiliev; Y Vazdik; C Veelken; A Vest; A Vichnevski; V Volchinski; K Wacker; J Wagner; R Wallny; B Waugh; G Weber; R Weber; D Wegener; C Werner; N Werner; M Wessels; B Wessling; M Winde; GG Winter; C Wissing; EE Woehrling; E Wunsch; AC Wyatt; J Zacek; J Zalesak; Z Zhang; A Zhokin; F Zomer; M zur Nedden
• Department/s: Particle and nuclear physics
• Publishing year: 2003
• Language: English
• Pages: 241-257
• Publication/Series: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics
• Volume: 561
• Issue: 3-4
• Links: http://dx.doi.org/10.1016/S0370-2693(03)00497-0
• Document type: Journal article
• Publisher: Elsevier
• Topic: Subatomic Physics
• Status: Published
• ISBN/ISSN/Other: ISSN: 0370-2693