Search for Compositeness, Leptoquarks and Large Extra Dimensions in Contact Interactions at HERA

The reaction is studied with the H1 detector at HERA. The data cover momentum transfers between and and correspond to an integrated luminosity of "!$# %'&)(+* . The differential cross section ,'-/.0,1 is compared to the Standard Model expectation for neutral current scattering and analysed to search for 2 3 452 3 6 6 4 contact interactions. No evidence for new phenomena is observed. The results are used to set limits on scales within models of electron–quark compositeness, quark form factors and the exchange of virtual heavy leptoquarks. A search for gravitational effects mediated through the exchange of virtual gravitons which propagate into large extra dimensions is presented. Submitted to Physics Letters B C. Adloff , V. Andreev , B. Andrieu , V. Arkadov , A. Astvatsatourov , I. Ayyaz , A. Babaev , J. Bähr , P. Baranov , E. Barrelet , W. Bartel * , U. Bassler , P. Bate * , A. Beglarian , O. Behnke * , C. Beier * , A. Belousov , T. Benisch * , Ch. Berger * , G. Bernardi , T. Berndt * , G. Bertrand-Coremans , J.C. Bizot , K. Borras , V. Boudry , W. Braunschweig * , V. Brisson , H.-B. Bröker , D.P. Brown * , W. Brückner * , P. Bruel , D. Bruncko * , J. Bürger * , F.W. Büsser * * , A. Bunyatyan * , H. Burkhardt * , A. Burrage * , G. Buschhorn , A.J. Campbell * , J. Cao , T. Carli , S. Caron * , E. Chabert , D. Clarke , B. Clerbaux , C. Collard , J.G. Contreras * , J.A. Coughlan , M.-C. Cousinou , B.E. Cox * , G. Cozzika , J. Cvach , J.B. Dainton * , W.D. Dau * , K. Daum , M. David , M. Davidsson , B. Delcourt , N. Delerue , R. Demirchyan , A. De Roeck * , E.A. De Wolf , C. Diaconu , P. Dixon * , V. Dodonov * , K.T. Donovan * , J.D. Dowell , A. Droutskoi , C. Duprel , J. Ebert , 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 * , F. Ferrarotto * , S. Ferron , M. Fleischer * , G. Flügge , A. Fomenko , I. Foresti , J. Formánek , J.M. Foster * , G. Franke * , E. Gabathuler * , K. Gabathuler , J. Garvey , J. Gassner , J. Gayler * , R. Gerhards * , S. Ghazaryan , L. Goerlich , N. Gogitidze , M. Goldberg , C. Goodwin , C. Grab , H. Grässler , T. Greenshaw * , G. Grindhammer , T. Hadig * , D. Haidt * , L. Hajduk , V. Haustein , W.J. Haynes , B. Heinemann * , G. Heinzelmann * * , R.C.W. Henderson * , S. Hengstmann , H. Henschel , R. Heremans , G. Herrera * , I. Herynek , M. Hilgers , K.H. Hiller , C.D. Hilton * , J. Hladký , P. Höting , D. Hoffmann * , W. Hoprich * , R. Horisberger , S. Hurling * , M. Ibbotson * , Ç. İşsever , M. Jacquet , M. Jaffre , L. Janauschek , D.M. Jansen * , X. Janssen , V. Jemanov * * , L. Jönsson , D.P. Johnson , M.A.S. Jones * , H. Jung , H.K. Kästli , D. Kant * , M. Kapichine , M. Karlsson , O. Karschnick * * , O. Kaufmann * , M. Kausch * , F. Keil * , N. Keller * , J. Kennedy * , I.R. Kenyon , S. Kermiche , C. Kiesling , M. Klein , C. Kleinwort * , G. Knies * , B. Koblitz , H. Kolanoski , S.D. Kolya * , V. Korbel * , P. Kostka , S.K. Kotelnikov , M.W. Krasny , H. Krehbiel * , J. Kroseberg , D. Krücker , K. Krüger * , A. Küpper , T. Kuhr * * , T. Kurča * , R. Kutuev * , W. Lachnit * , R. Lahmann * , D. Lamb , M.P.J. Landon * , W. Lange , T. Laštovička , A. Lebedev , B. Leißner * , R. Lemrani * , V. Lendermann , S. Levonian * , M. Lindstroem , G. Lobo , E. Lobodzinska * , B. Lobodzinski * , N. Loktionova , V. Lubimov , S. Lüders , D. Lüke * , L. Lytkin * , N. Magnussen , H. Mahlke-Krüger * , N. Malden * , E. Malinovski , I. Malinovski , R. Maraček , P. Marage , J. Marks * , R. Marshall * , H.-U. Martyn * , J. Martyniak , S.J. Maxfield * , A. Mehta * , K. Meier * , P. Merkel * , F. Metlica * , A. 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 , D. Müller , K. Müller * , P. Murı́n * , V. Nagovizin , B. Naroska * * , J. Naumann , Th. Naumann , I. Négri , G. Nellen , P.R. Newman , T.C. Nicholls , F. Niebergall * * , C. Niebuhr * , O. Nix * , G. Nowak , T. Nunnemann * , J.E. Olsson * , D. Ozerov , V. Panassik , C. Pascaud , G.D. Patel * , 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 * , S. Riess * * , E. Rizvi , P. Robmann , R. Roosen , A. Rostovtsev , C. Royon , S. Rusakov , K. Rybicki , D.P.C. Sankey , J. Scheins * , F.-P. Schilling * , S. Schleif * , P. Schleper * , D. Schmidt , D. Schmidt * , L. Schoeffel , A. Schöning , T. Schörner , V. Schröder * , H.-C. Schultz-Coulon * , K. Sedlák , F. Sefkow , V. Shekelyan , I. Sheviakov , L.N. Shtarkov , G. Siegmon * , P. Sievers * , Y. Sirois , T. Sloan * , P. Smirnov , M. Smith * , V. Solochenko , Y. Soloviev , V. Spaskov , A. Specka , H. Spitzer * * , R. Stamen , J. Steinhart * * , B. Stella * , A. Stellberger * , J. Stiewe * , U. Straumann , W. Struczinski , M. Swart * , M. Taševský , V. Tchernyshov , S. Tchetchelnitski , G. Thompson * , P.D. Thompson , N. Tobien * , D. Traynor * , P. Truöl , G. Tsipolitis , J. Turnau , J.E. Turney * , E. Tzamariudaki , S. Udluft , A. Usik , S. Valkár , A. Valkárová , C. Vallée , P. Van Mechelen , Y. Vazdik , S. von Dombrowski , K. Wacker , R. Wallny * , T. Walter , B. Waugh * , G. Weber * * , M. Weber * , D. Wegener , A. Wegner * * , T. Wengler * , M. Werner * , G. White * , S. Wiesand , T. Wilksen * , M. Winde , G.-G. Winter * , C. Wissing , M. Wobisch , H. Wollatz * , E. Wünsch * , A.C. Wyatt * , J. Žáček , J. Zálešák , Z. Zhang , A. Zhokin , F. Zomer , J. Zsembery and M. zur Nedden * * I. Physikalisches Institut der RWTH, Aachen, Germany III. Physikalisches Institut der RWTH, Aachen, Germany School of Physics and Space Research, University of Birmingham, Birmingham, UK Inter-University Institute for High Energies ULB-VUB, Brussels; Universitaire Instelling Antwerpen, Wilrijk; Belgium Rutherford Appleton Laboratory, Chilton, Didcot, UK Institute for Nuclear Physics, Cracow, Poland Institut für Physik, Universität Dortmund, Dortmund, Germany Joint Institute for Nuclear Research, Dubna, Russia DSM/DAPNIA, CEA/Saclay, Gif-sur-Yvette, France * DESY, Hamburg, Germany * * II. Institut für Experimentalphysik, Universität Hamburg, Hamburg, Germany * Max-Planck-Institut für Kernphysik, Heidelberg, Germany * Physikalisches Institut, Universität Heidelberg, Heidelberg, Germany * Kirchhoff-Institut für Physik, Universität Heidelberg, Heidelberg, Germany * Institut für experimentelle und angewandte Physik, Universität Kiel, Kiel, Germany * Institute of Experimental Physics, Slovak Academy of Sciences, Košice, Slovak Republic * School of Physics and Chemistry, University of Lancaster, Lancaster, UK * Department of Physics, University of Liverpool, Liverpool, UK * Queen Mary and Westfield College, London, UK Physics Department, University of Lund, Lund, Sweden * Department of Physics and Astronomy, University of Manchester, Manchester, UK CPPM, CNRS/IN2P3 Univ Mediterranee, Marseille France Institute for Theoretical and Experimental Physics, Moscow, Russia Lebedev Physical Institute, Moscow, Russia Max-Planck-Institut für Physik, München, Germany LAL, Université de Paris-Sud, IN2P3-CNRS, Orsay, France LPNHE, École Polytechnique, IN2P3-CNRS, Palaiseau, France LPNHE, Universités Paris VI and VII, IN2P3-CNRS, Paris, France Institute of Physics, Academy of Sciences of the Czech Republic, Praha, Czech Republic Faculty of Mathematics and Physics, Charles University, Praha, Czech Republic * INFN Roma 1 and Dipartimento di Fisica, Università Roma 3, Roma, Italy Paul Scherrer Institut, Villigen, Switzerland Fachbereich Physik, Bergische Universität Gesamthochschule Wuppertal, Wuppertal, Germany Yerevan Physics Institute, Yerevan, Armenia DESY, Zeuthen, Germany Institut für Teilchenphysik, ETH, Zürich, Switzerland Physik-Institut der Universität Zürich, Zürich, Switzerland Present address: Institut für Physik, Humboldt-Universität, Berlin, Germany Also at Rechenzentrum, Bergische Universität Gesamthochschule Wuppertal, Wuppertal, Germany Also at Institut für Experimentelle Kernphysik, Universität Karlsruhe, Karlsruhe, Germany * Also at Dept. Fis. Ap. CINVESTAV, Mérida, Yucatán, México Also at University of P.J. Šafárik, Košice, Slovak Republic Also at CERN, Geneva, Switzerland Deceased Supported by the Bundesministerium für Bildung, Wissenschaft, Forschung und Technologie, FRG, under contract numbers 7AC17P, 7AC47P, 7DO55P, 7HH17I, 7HH27P, 7HD17P, 7HD27P, 7KI17I, 6MP17I and 7WT87P Supported by the UK Particle Physics and Astronomy Research Council, and formerly by the UK Science and Engineering Research Council Supported by FNRS-FWO, IISN-IIKW Partially Supported by the Polish State Committee for Scientific Research, grant No. 2P0310318 and SPUB/DESY/P-03/DZ 1/99 Supported by the Deutsche Forschungsgemeinschaft Supported by VEGA SR grant no. 2/5167/98 Supported by the Swedish Natural Science Research Council Supported by Russian Foundation for Basic Research grant no. 96-02-00019 Supported by GA AVČR grant number no. A1010821 Supported by the Swiss National Science Foundation Supported by CONACyT