A search for leptoquark bosons and lepton flavor violation in e(+)p collisions at HERA

Authors
Adloff, C Andreev, V Andrieu, B Arkadov, V Astvatsatourov, A Ayyaz, I Babaev, A Bahr, J Baranov, P Barrelet, E Bartel, W Bassler, U Bate, P Beglarian, A Behnke, O Behrend, HJ Beier, C Belousov, A Berger, C Bernardi, G Berndt, T Bertrand-Coremans, G Biddulph, P Bizot, JC Boudry, V Braunschweig, W Brisson, V Broker, HB Brown, DP Bruckner, W Bruel, P Bruncko, D Burger, J Busser, FW Bunyatyan, A Burke, S Burrage, A Buschhorn, G Calvet, D Campbell, AJ Carli, T Chabert, E Charlet, M Clarke, D Clerbaux, B Contreras, JG Cormack, C Coughlan, JA Cousinou, MC Cox, BE Cozzika, G Cvach, J Dainton, JB Dau, WD Daum, K David, M Davidsson, M De Roeck, A De Wolf, EA Delcourt, B Demirchyan, R Diaconu, C Dirkmann, M Dixon, P Dodonov, V Donovan, KT Dowell, JD Droutskoi, A Ebert, J Eckerlin, G Eckstein, D Efremenko, V Egli, S Eichler, R Eisele, F Eisenhandler, E Elsen, E Enzenberger, M Erdmann, M Fahr, AB Faulkner, PJW Favart, L Fedotov, A Felst, R Feltesse, J Ferencei, J Ferrarotto, F Ferron, S Fleischer, M Flugge, G Fomenko, A Formanek, J Foster, JM Franke, G Gabathuler, E Gabathuler, K Gaede, F Garvey, J Gassner, J Gayler, J Gerhards, R Ghazaryan, S Glazov, A Goerlich, L Gogitidze, N Goldberg, M Gorelov, I Grab, C Grassler, H Greenshaw, T Griffiths, RK Grindhammer, G Hadig, T Haidt, D Hajduk, L Hampel, M Haustein, V Haynes, WJ Heinemann, B Heinzelmann, G Henderson, RCW Hengstmann, S Henschel, H Heremans, R Herrera, G Herynek, I Hewitt, K Hilgers, M Hiller, KH Hilton, CD Hladky, J Hoting, P Hoffmann, D Horisberger, R Hurling, S Ibbotson, M Issever, C Jacquet, M Jaffre, M Janauschek, L Jansen, DM Jonsson, L Johnson, DP Jones, M Jung, H Kastli, HK Kander, M Kant, D Kapichine, M Karlsson, M Karschnick, O Kaufmann, O Kausch, M Keil, F Keller, N Kenyon, IR Kermiche, S Kiesling, C Klein, M Kleinwort, C Knies, G Kohne, JH Kolanoski, H Kolya, SD Korbel, V Kostka, P Kotelnikov, SK Kramerkamper, T Krasny, MW Krehbiel, H Krucker, D Kruger, K Kupper, A Kuster, H Kuhlen, M Kurca, T Lachnit, W Lahmann, R Lamb, D Landon, MPJ Lange, W Langenegger, U Lebedev, A Lehner, F Lemaitre, V Lemrani, R Lendermann, V Levonian, S Lindstroem, M Lobo, G Lobodzinska, E Lubimov, V Luders, S Luke, D Lytkin, L Magnussen, N Mahlke-Kruger, H Malden, N Malinovski, E Malinovski, I Maracek, R Marage, P Marks, J Marshall, R Martyn, HU Martyniak, J Maxfield, SJ McMahon, TR Mehta, A Meier, K Merkel, P Metlica, F Meyer, A Meyer, H Meyer, J Meyer, PO Mikocki, S Milstead, D Mohr, R Mohrdieck, S Mondragon, MN Moreau, F Morozov, A Morris, JV Muller, D Muller, K Murin, P Nagovizin, V Naroska, B Naumann, J Naumann, T Negri, I Newman, PR Nguyen, HK Nicholls, TC Niebergall, F Niebuhr, C Niedzballa, C Niggli, H Nix, O Nowak, G Nunnemann, T Oberlack, H Olsson, JE Ozerov, D Palmen, P Panassik, V Pascaud, C Passaggio, S Patel, GD Pawletta, H Perez, E Phillips, JP Pieuchot, A Pitzl, D Poschl, R Potashnikova, I Povh, B Rabbertz, K Radel, G Rauschenberger, J Reimer, P Reimer, P Reisert, B Reyna, D Riess, S Rizvi, E Robmann, P Roosen, R Rosenbauer, K Rostovtsev, A Royon, C Rusakov, S Rybicki, K Sankey, DPC Schacht, P Scheins, J Schilling, FP Schleif, S Schleper, P Schmidt, D Schmidt, D Schoeffel, L Schorner, T Schroder, V Schultz-Coulon, HC Sefkow, F Shekelyan, V Sheviakov, I Shtarkov, LN Siegmon, G Sirois, Y Sloan, T Smirnov, P Smith, M Solochenko, V Soloviev, Y Spaskov, V Specka, A Spitzer, H Squinabol, F Stamen, R Steinhart, J Stella, B Stellberger, A Stiewe, J Straumann, U Struczinski, W Sutton, JP Swart, M Tapprogge, S Tasevsky, M Tchernyshov, V Tchetchelnitski, S Thompson, G Thompson, PD Tobien, N Todenhagen, R Traynor, D Truol, P Tsipolitis, G Turnau, J Tzamariudaki, E Udluft, S Usik, A Valkar, S Valkarova, A Vallee, C Van Haecke, A Van Mechelen, P Vazdik, Y Villet, G Wacker, K Wallny, R Walter, T Waugh, B Weber, G Weber, M Wegener, D Wegner, A Wengler, T Werner, M West, LR White, G Wiesand, S Wilksen, T Winde, M Winter, GG Wissing, C Wittek, C Wobisch, M Wollatz, H Wunsch, E Zacek, J Zalesak, J Zhang, Z Zhokin, A Zini, P Zomer, F Zsembery, J zur Nedden, M
Citation
C. Adloff et al., A search for leptoquark bosons and lepton flavor violation in e(+)p collisions at HERA, EUR PHY J C, 11(3), 1999, pp. 447-471
Citations number
88
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics
Journal title
EUROPEAN PHYSICAL JOURNAL C
ISSN journal
1434-6044 → ACNP
Volume
11
Issue
3
Year of publication
1999
Pages
447 - 471
Database
ISI
SICI code
1434-6044(199912)11:3<447:ASFLBA>2.0.ZU;2-M
Abstract
A search for new bosons possessing couplings to lepton-quark pairs is perfo rmed in the H1 experiment at HERA using 1994 to 1997 data corresponding to an integrated luminosity of 37 pb(-1). First generation leptoquarks (LQs) a re searched in very high Q(2) neutral (NC) and charged (CC) current data sa mples. The measurements are compared to Standard Model (SM) expectations fr om deep-inelastic scattering (DIS). A deviation in the Q(2) spectrum previo usly observed in the 1994 to 1996 dataset at Q(2)greater than or similar to 15000 GeV2 remains, though with less significance. This deviation correspo nded to a clustering in the invariant mass spectrum at M similar or equal t o 200 GeV which is not observed with the 1997 dataset alone. The NC DIS dat a is used to constrain the Yukawa couplings lambda of first generation scal ar and vector LQs in the Buchmuller-Ruckl-Wyler effective model. Scalar LQs are excluded for masses up to 275 GeV for a coupling of electromagnetic st rength, lambda = 0.3. A sensitivity to coupling values less than or similar to 1 is established for masses up to 400 GeV for any LQ type. The NC and C C DIS data are combined to constrain lambda for arbitrary branching ratios of the LQ into eq in a generic model. For a decay branching ratio into e(+) u pairs as small as 10%, LQ masses up to 260 GeV are ruled out for lambda = 0.3. LQs possessing couplings to mixed fermion generations, which could le ad to signals of lepton flavor violation (LFV), are searched in events with a high transverse momentum mu or tau. No mu + X or tau + X event candidate is found that is compatible with LQ kinematics. Constraints are set on the Yukawa coupling involving the mu and tau lepton in a yet unexplored mass r ange.