A Search for Leptoquark Bosons in e−p Collisions at HERA H1 Collaboration

A search for scalar and vector leptoquarks coupling to first generation fermions is performed in the H1 experiment at the ep collider HERA. The analysis uses e−p data collected in 1998 and 1999 at a centre-of-mass energy of 320 GeV, corresponding to an integrated luminosity of ∼ 15 pb. No evidence for the direct production of such particles is found in a data sample with a large transverse momentum final state electron or with large missing transverse momentum, and constraints on leptoquark models are established. For a Yukawa coupling of electromagnetic strength leptoquarks are excluded for masses up to ∼ 290 GeV. This analysis complements the leptoquark searches performed previously using data collected whilst HERA was operating with positrons instead of electrons. To be submitted to Phys. Lett. B C. Adloff, V. Andreev, B. Andrieu, T. Anthonis, V. Arkadov, A. Astvatsatourov, A. Babaev, J. Bähr, P. Baranov, E. Barrelet, W. Bartel, P. Bate, J. Becker, A. Beglarian, O. Behnke, C. Beier, A. Belousov, T. Benisch, Ch. Berger, T. Berndt, J.C. Bizot, J. Boehme, V. Boudry, W. Braunschweig, V. Brisson, H.-B. Bröker, D.P. Brown, W. Brückner, D. Bruncko, J. Bürger, F.W. Büsser, A. Bunyatyan, A. Burrage, G. Buschhorn, L. Bystritskaya, A.J. Campbell, J. Cao, S. Caron, F. Cassol-Brunner, D. Clarke, B. Clerbaux, C. Collard, J.G. Contreras, Y.R. Coppens, J.A. Coughlan, M.-C. Cousinou, B.E. Cox, G. Cozzika, J. Cvach, J.B. Dainton, W.D. Dau, K. Daum, M. Davidsson, B. Delcourt, N. Delerue, R. Demirchyan, A. De Roeck, E.A. De Wolf, C. Diaconu, J. Dingfelder, P. Dixon, V. Dodonov, J.D. Dowell, A. Droutskoi, A. Dubak, C. Duprel, G. Eckerlin, D. Eckstein, V. Efremenko, S. Egli, R. Eichler, F. Eisele, E. Eisenhandler, M. Ellerbrock, E. Elsen, M. Erdmann, W. Erdmann, P.J.W. Faulkner, L. Favart, A. Fedotov, R. Felst, J. Ferencei, S. Ferron, M. Fleischer, Y.H. Fleming, G. Flügge, A. Fomenko, I. Foresti, J. Formánek, G. Franke, E. Gabathuler, K. Gabathuler, J. Garvey, J. Gassner, J. Gayler, R. Gerhards, C. Gerlich, S. Ghazaryan, L. Goerlich, N. Gogitidze, M. Goldberg, C. Grab, H. Grässler, T. Greenshaw, G. Grindhammer, T. Hadig, D. Haidt, L. Hajduk, J. Haller, W.J. Haynes, B. Heinemann, G. Heinzelmann, R.C.W. Henderson, S. Hengstmann, H. Henschel, R. Heremans, G. Herrera, I. Herynek, M. Hildebrandt, M. Hilgers, K.H. Hiller, J. Hladký, P. Höting, D. Hoffmann, R. Horisberger, S. Hurling, M. Ibbotson, Ç. İşsever, M. Jacquet, M. Jaffre, L. Janauschek, X. Janssen, V. Jemanov, L. Jönsson, C. Johnson, D.P. Johnson, M.A.S. Jones, H. Jung, D. Kant, M. Kapichine, M. Karlsson, O. Karschnick, F. Keil, N. Keller, J. Kennedy, I.R. Kenyon, S. Kermiche, C. Kiesling, P. Kjellberg, M. Klein, C. Kleinwort, T. Kluge, G. Knies, B. Koblitz, S.D. Kolya, V. Korbel, P. Kostka, S.K. Kotelnikov, R. Koutouev, A. Koutov, H. Krehbiel, J. Kroseberg, K. Krüger, A. Küpper, T. Kuhr, T. Kurča, R. Lahmann, D. Lamb, M.P.J. Landon, W. Lange, T. Laštovička, P. Laycock, E. Lebailly, A. Lebedev, B. Leißner, R. Lemrani, V. Lendermann, S. Levonian, M. Lindstroem, B. List, E. Lobodzinska, B. Lobodzinski, A. Loginov, N. Loktionova, V. Lubimov, S. Lüders, D. Lüke, L. Lytkin, H. MahlkeKrüger, N. Malden, E. Malinovski, I. Malinovski, R. Maraček, P. Marage, J. Marks, R. Marshall, H.-U. Martyn, J. Martyniak, S.J. Maxfield, D. Meer, A. Mehta, K. Meier, A.B. Meyer, H. Meyer, J. Meyer, P.-O. Meyer, S. Mikocki, D. Milstead, T. Mkrtchyan, R. Mohr, S. Mohrdieck, M.N. Mondragon, F. Moreau, A. Morozov, J.V. Morris, K. Müller, P. Murı́n, V. Nagovizin, B. Naroska, J. Naumann, Th. Naumann, G. Nellen, P.R. Newman, T.C. Nicholls, F. Niebergall, C. Niebuhr, O. Nix, G. Nowak, J.E. Olsson, D. Ozerov, V. Panassik, C. Pascaud, G.D. Patel, M. Peez, E. Perez, J.P. Phillips, D. Pitzl, R. Pöschl, I. Potachnikova, B. Povh, K. Rabbertz, G. Rädel, J. Rauschenberger, P. Reimer, B. Reisert, D. Reyna, C. Risler, E. Rizvi, P. Robmann, R. Roosen, A. Rostovtsev, S. Rusakov, K. Rybicki, D.P.C. Sankey, J. Scheins, F.-P. Schilling, P. Schleper, D. Schmidt, D. Schmidt, S. Schmidt, S. Schmitt, M. Schneider, L. Schoeffel, A. Schöning, T. Schörner, V. Schröder, H.-C. Schultz-Coulon, C. Schwanenberger, K. Sedlák, F. Sefkow, V. Shekelyan, I. Sheviakov, L.N. Shtarkov, Y. Sirois, T. Sloan, P. Smirnov, Y. Soloviev, D. South, V. Spaskov, A. Specka, H. Spitzer, R. Stamen, B. Stella, J. Stiewe, U. Straumann, M. Swart, M. Taševský, V. Tchernyshov, S. Tchetchelnitski, G. Thompson, P.D. Thompson, N. Tobien, D. Traynor, P. Truöl, G. Tsipolitis, I. Tsurin, J. Turnau, J.E. Turney, E. Tzamariudaki, S. Udluft, M. Urban, A. Usik, S. Valkár, A. Valkárová, C. Vallée, P. Van Mechelen, S. Vassiliev, Y. Vazdik, A. Vichnevski, K. Wacker, R. Wallny, B. Waugh,