Search for excited electrons in ep collisions at HERA
F. D. AaronNational Institute for Physics and Nuclear Engineering (NIPNE), Bucharest, RomaniaC. AlexaNational Institute for Physics and Nuclear Engineering (NIPNE), Bucharest, RomaniaV. AndreevLebedev Physical Institute, Moscow, Russia 19B. AntunovićS. AplinA. AsmoneSapienza University of Rome, Rome, ItalyA. AstvatsatourovInter-University Institute for High Energies ULB-VUB, Universiteit Antwerpen, Antwerpen, Belgium 14Alessandro BacchettaS. BackovićFaculty of Science, University of Montenegro, Podgorica, Montenegro 19A. BaghdasaryanYerevan Physics Institute, Yerevan, ArmeniaP. BaranovLebedev Physical Institute, Moscow, Russia 19E. BarreletInstitut National de Physique Nucléaire et de Physique des ParticulesW. BartelM. BeckinghamK. BegzsurenMongolian Academy of Sciences, Ulaanbaatar, MongoliaO. BehnkePhysikalisches Institut, Universität Heidelberg, Heidelberg, Germany 12A. BelousovLebedev Physical Institute, Moscow, Russia 19N. BergerInstitut für Teilchenphysik, ETH, Zürich, Switzerland 21J.C. BizotUniversité Paris-Sud, Orsay, FranceM.-O. BoenigInstitut für Physik, TU Dortmund, Dortmund, Germany 12V. BoudryLLR, Ecole Polytechnique, IN2P3-CNRS, Palaiseau, FranceI. Božović-Jelisavc̆ićVinca Institute of Nuclear Sciences, Belgrade, SerbiaJ. BraciníkUniversity of Birmingham, Birmingham, United KingdomG. BrandtMartin BrinkmannV. BrissonLAL, Université Paris-Sud, CNRS/IN2P3, Orsay, FranceD. BrunckoSlovak Academy of Sciences, Bratislava, SlovakiaA. BunyatyanMax Planck Society, Munich, GermanyG. BuschhornMax Planck Society, Munich, GermanyL. BystritskayaInstitute for Theoretical and Experimental Physics, Moscow, RussiaAlan CampbellK. B. Cantun AvilaCenter for Research and Advanced Studies of the National Polytechnic Institute, Mexico City, MexicoF. Cassol-BrunnerCentre National de la Recherche Scientifique, Paris, FranceK. ČernýFaculty of Mathematics and Physics, Charles University, Praha, Czech Republic 20V. ČernýInstitute of Experimental Physics, Slovak Academy of Sciences, Košice, Slovak Republic 16V. ChekelianMax Planck Society, Munich, GermanyA. CholewaJ.G. ContrerasCenter for Research and Advanced Studies of the National Polytechnic Institute, Mexico City, MexicoJ. A. CoughlanRutherford Appleton Laboratory, Chilton, Didcot, UK 13G. CozzikaCEA, DSM/DAPNIA, CE-Saclay, Gif-sur-Yvette, FranceJ. CvachInstitute of Physics, Academy of Sciences of the Czech Republic, Praha, Czech Republic 20J.B. DaintonDepartment of Physics, University of Liverpool, Liverpool, UK 13K. DaumFachbereich C, Universität Wuppertal, Wuppertal, GermanyMichal DeákY. de BoerDESY, Hamburg, GermanyB. DelcourtUniversité Paris-Sud, Orsay, FranceM. Del DeganInstitut für Teilchenphysik, ETH, Zürich, Switzerland 21J. DelvaxUniversity of Antwerp, Antwerp, BelgiumA. De RoeckDESY, Hamburg, GermanyE. A. De WolfUniversity of Antwerp, Antwerp, BelgiumC. DiaconuCentre National de la Recherche Scientifique, Paris, FranceV. DodonovMax Planck Institute for Nuclear PhysicsA. DossanovMax Planck Society, Munich, GermanyA. DubakFaculty of Science, University of Montenegro, Podgorica, Montenegro 19G. EckerlinV. EfremenkoInstitute for Theoretical and Experimental Physics, Moscow, RussiaS. EgliPaul Scherrer Institut, Villigen, SwitzerlandA. EliseevLebedev Physical Institute, Moscow, Russia 19E. ElsenS. EssenovInstitute for Theoretical and Experimental Physics, Moscow, RussiaA. FalkiewiczInstitute for Nuclear Physics, Cracow, Poland 15Peter FaulknerSchool of Physics and Astronomy, University of Birmingham, Birmingham, UK 13L. FavartUniversity of Antwerp, Antwerp, BelgiumA. FedotovInstitute for Theoretical and Experimental Physics, Moscow, RussiaR. FelstJ. FeltesseDSM (Netherlands), Heerlen, NetherlandsJ. FerenceiInstitute of Experimental Physics, Slovak Academy of Sciences, Košice, Slovak Republic 16L. FinkeM. FleischerA. FomenkoLebedev Physical Institute, Moscow, Russia 19E. GabathulerDepartment of Physics, University of Liverpool, Liverpool, UK 13J. GaylerDESY, Hamburg, GermanyS. GhazaryanYerevan Physics Institute, Yerevan, ArmeniaA. GlazovI. GlushkovDESY, Zeuthen, GermanyL. GoerlichInstitute for Nuclear Physics, Cracow, Poland 15M. GoettlichInstitut für Experimentalphysik, Universität Hamburg, Hamburg, Germany 12N. GogitidzeLebedev Physical Institute, Moscow, Russia 19M. GouzevitchLLR, Ecole Polytechnique, IN2P3-CNRS, Palaiseau, FranceC. GrabInstitut für Teilchenphysik, ETH, Zürich, Switzerland 21T. GreenshawDepartment of Physics, University of Liverpool, Liverpool, UK 13B.R. GrellG. GrindhammerMax-Planck-Institut für Physik, München, GermanyS. HabibInstitut für Experimentalphysik, Universität Hamburg, Hamburg, Germany 12D. HaidtDESY, Hamburg, GermanyM. HanssonPhysics Department, University of Lund, Lund, Sweden 17C. HelebrantDESY, Hamburg, GermanyR. C. W. HendersonDepartment of Physics, University of Lancaster, Lancaster, UK 13H. HenschelDESY, Zeuthen, GermanyG. HerreraCenter for Research and Advanced Studies of the National Polytechnic Institute, Mexico City, MexicoM. HildebrandtPaul Scherrer Institut, Villigen, SwitzerlandK. H. HillerDESY, Zeuthen, GermanyD. HoffmannCPPM, CNRS/IN2P3, Univ. Mediterranee, Marseille, FranceR. HorisbergerPaul Scherrer Institut, Villigen, SwitzerlandA. HovhannisyanYerevan Physics Institute, Yerevan, ArmeniaT. HreusInter-University Institute for High Energies ULB-VUB, Universiteit Antwerpen, Antwerpen, Belgium 14M. JacquetInstitut National de Physique Nucléaire et de Physique des ParticulesM.E. JanssenX. JanssenUniversity of Antwerp, Antwerp, BelgiumV. JemanovInstitut für Experimentalphysik, Universität Hamburg, Hamburg, Germany 12
2008en
ABI
Abstract
A search for excited electrons is performed using the full e ± p data sample collected by the H1 experiment at HERA, corresponding to a total luminosity of 475 pb −1 . The electroweak decays of excited electrons e ∗ → e γ , e ∗ → e Z and e ∗ → ν W with subsequent hadronic or leptonic decays of the W and Z bosons are considered. No evidence for excited electron production is found. Mass dependent exclusion limits on e ∗ production cross sections and on the ratio f / Λ of the coupling to the compositeness scale are derived within gauge mediated models. These limits extend the excluded region compared to previous excited electron searches. The e ∗ production via contact interactions is also addressed for the first time in ep collisions.