W Production and the Search for Events with an Isolated High-Energy Lepton and Missing Transverse Momentum at HERA

نویسندگان

  • L. Bellagamba
  • D. Boscherini
  • A. Bruni
  • G. Bruni
  • G. Cara Romeo
  • G. Castellini
چکیده

A search for the leptonic decays of W bosons produced in the reaction ep → eWX at a centre-of-mass energy of 300 GeV has been performed with the ZEUS detector at HERA using an integrated luminosity of 47.7 pb. Three events consistent with W → eν decay are found, giving a cross section of 0.9 −0.7±0.2 pb, in good agreement with the Standard Model prediction. The corresponding 95% C.L. upper limit on the cross section is 3.3 pb. A search for the decay W → μν has a smaller selection efficiency and yields no candidate events. Limits on the cross section for W production with large hadronic transverse momentum have been used to constrain the anomalous couplings ∆κ and λ at the WWγ vertex. A search for high-transverse-momentum isolated tracks in events with large missing transverse momentum yields results in good agreement with Standard Model expectations, in contrast to a recent report by the H1 collaboration of the observation of an excess of such events. The ZEUS Collaboration J. Breitweg, S. Chekanov, M. Derrick, D. Krakauer, S. Magill, B. Musgrave, A. Pellegrino, J. Repond, R. Stanek, R. Yoshida Argonne National Laboratory, Argonne, IL, USA p M.C.K. Mattingly Andrews University, Berrien Springs, MI, USA G. Abbiendi, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti, G. Levi, A. Margotti, T. Massam, R. Nania, F. Palmonari, A. Pesci, A. Polini, G. Sartorelli, Y. Zamora Garcia, A. Zichichi University and INFN Bologna, Bologna, Italy f C. Amelung, A. Bornheim, I. Brock, K. Coböken, J. Crittenden, R. Deffner, M. Eckert, H. Hartmann, K. Heinloth, E. Hilger, H.-P. Jakob, A. Kappes, U.F. Katz, R. Kerger, E. Paul, J. Rautenberg, H. Schnurbusch, A. Stifutkin, J. Tandler, A. Weber, H. Wieber Physikalisches Institut der Universität Bonn, Bonn, Germany c D.S. Bailey, O. Barret, W.N. Cottingham, B. Foster, G.P. Heath, H.F. Heath, J.D. McFall, D. Piccioni, J. Scott, R.J. Tapper H.H. Wills Physics Laboratory, University of Bristol, Bristol, U.K. o r M. Capua, A. Mastroberardino, M. Schioppa, G. Susinno Calabria University, Physics Dept.and INFN, Cosenza, Italy f H.Y. Jeoung, J.Y. Kim, J.H. Lee, I.T. Lim, K.J. Ma, M.Y. Pac Chonnam National University, Kwangju, Korea h A. Caldwell, N. Cartiglia, Z. Jing, W. Liu, B. Mellado, J.A. Parsons, S. Ritz, R. Sacchi, S. Sampson, F. Sciulli, Q. Zhu Columbia University, Nevis Labs., Irvington on Hudson, N.Y., USA q J. Chwastowski, A. Eskreys, J. Figiel, K. Klimek, K. Olkiewicz, M.B. Przybycień, P. Stopa, L. Zawiejski Inst. of Nuclear Physics, Cracow, Poland j L. Adamczyk, B. Bednarek, K. Jeleń, D. Kisielewska, A.M. Kowal, T. Kowalski, M. Przybycień, E. Rulikowska-Zarȩbska, L. Suszycki, J. Zaja̧c Faculty of Physics and Nuclear Techniques, Academy of Mining and Metallurgy, Cracow, Poland j Z. Duliński, A. Kotański Jagellonian Univ., Dept. of Physics, Cracow, Poland k

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تاریخ انتشار 1999