Zγ production and limits on anomalous ZZγ and Zγγ couplings in p over(p, ̄) collisions at sqrt(s) = 1.96  TeV

We present a study of eeγ and μμγ events using 1109 (1009) pb-1 of data in the electron (muon) channel, respectively. These data were collected with the DØ detector at the Fermilab Tevatron p over(p, ̄) collider at sqrt(s) = 1.96   TeV. Having observed 453 (515) candidates in the eeγ (μμγ) final sta...

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Bibliographic Details
Main Authors: Abazov, V, Abbott, B, Abolins, M, Acharya, B, Adams, M, Adams, T, Aguilo, E, Ahn, S, Ahsan, M, Alexeev, G, Alkhazov, G, Alton, A, Alverson, G, Alves, G, Anastasoaie, M, Ancu, L, Andeen, T, Anderson, S, Andrieu, B, Anzelc, MS, Arnoud, Y, Arov, M, Arthaud, M, Askew, A, Åsman, B
Format: Journal article
Language:English
Published: 2007
Description
Summary:We present a study of eeγ and μμγ events using 1109 (1009) pb-1 of data in the electron (muon) channel, respectively. These data were collected with the DØ detector at the Fermilab Tevatron p over(p, ̄) collider at sqrt(s) = 1.96   TeV. Having observed 453 (515) candidates in the eeγ (μμγ) final state, we measure the Zγ production cross section for a photon with transverse energy ET > 7   GeV, separation between the photon and leptons Δ Rℓ γ > 0.7, and invariant mass of the di-lepton pair Mℓ ℓ > 30   GeV / c2, to be 4.96 ± 0.30 (stat . + syst .) ± 0.30 (lumi .)   pb, in agreement with the Standard Model prediction of 4.74 ± 0.22   pb. This is the most precise Zγ cross section measurement at a hadron collider. We set limits on anomalous trilinear Zγγ and ZZγ gauge boson couplings of - 0.085 < h30γ < 0.084, - 0.0053 < h40γ < 0.0054 and - 0.083 < h30Z < 0.082, - 0.0053 < h40Z < 0.0054 at the 95% C.L. for the form-factor scale Λ = 1.2   TeV.