2 research outputs found

    Search for Excited Electrons in ep Collisions at HERA

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    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. © 2008 Elsevier B.V. All rights reserved.0DESY-08-052 / arxiv:0805.4530SCOPUS: ar.jinfo:eu-repo/semantics/publishe

    Multi-Lepton Production at High Transverse Momenta in ep Collisions at HERA

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    Processes leading to a final state with at least two high transverse momentum leptons (electrons or muons) are studied using the full e ± p data sample collected by the H1 experiment at HERA. The data correspond to an integrated luminosity of 463 pb -1. Di-lepton and tri-lepton event classes are investigated. Cross sections of the production of e + e - and μ + μ - pairs are derived in a restricted phase space dominated by photon-photon collisions. In general, good agreement is found with Standard Model predictions. Events are observed with a total scalar sum of lepton transverse momenta above 100   GeV where the Standard Model expectation is low. In this region, combining di-lepton and tri-lepton classes, five events are observed in e + p collisions, compared to a Standard Model expectation of 0.96 ± 0.12, while no such event is observed in e - p data for 0.64 ± 0.09 expected. © 2008 Elsevier B.V. All rights reserved.0DESY-08-065 / arxiv:0806.3987SCOPUS: ar.jinfo:eu-repo/semantics/publishe
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