Evidence for an Excess of Soft Photons in Hadronic Decays of Z^0

dc.creatorThe DELPHI Collaboration
dc.creatorAbdallah, J.
dc.date2006-04-19
dc.date.accessioned2026-07-07T11:58:13Z
dc.date.available2026-07-07T11:58:13Z
dc.descriptionSoft photons inside hadronic jets converted in front of the DELPHI main tracker (TPC) in events of qqbar disintegrations of the Z^0 were studied in the kinematic range 0.2 < E_gamma < 1 GeV and transverse momentum with respect to the closest jet direction p_T < 80 MeV/c. A clear excess of photons in the experimental data as compared to the Monte Carlo predictions is observed. This excess (uncorrected for the photon detection efficiency) is (1.17 +/- 0.06 +/- 0.27) x 10^{-3} gamma/jet in the specified kinematic region, while the expected level of the inner hadronic bremsstrahlung (which is not included in the Monte Carlo) is (0.340 +/- 0.001 +/- 0.038) x 10^{-3} gamma/jet. The ratio of the excess to the predicted bremsstrahlung rate is then (3.4 +/- 0.2 +/- 0.8), which is similar in strength to the anomalous soft photon signal observed in fixed target experiments with hadronic beams.
dc.description37 pages, 9 figures, Accepted by Eur. Phys. J. C
dc.identifierhttps://arxiv.org/abs/hep-ex/0604038
dc.identifierhttp://arxiv.org/abs/hep-ex/0604038
dc.identifierEur.Phys.J.C47:273-294,2006
dc.identifierdoi:10.1140/epjc/s2006-02568-8
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/206149
dc.subjectHigh Energy Physics - Experiment
dc.titleEvidence for an Excess of Soft Photons in Hadronic Decays of Z^0
dc.typetext

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