Evidence for an Excess of Soft Photons in Hadronic Decays of $Z^0$Vise andre og tillknytning
2006 (engelsk)Inngår i: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 47, nr 2, s. 273-294Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]
Soft photons inside hadronic jets converted in front of the DELPHI main tracker (TPC) in events of qq̄ disintegrations of the Z0 were studied in the kinematic range 0.2<Eγ<1 GeV and transverse momentum with respect to the closest jet direction pT<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)×10-3 γ/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)×10-3 γ/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.
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2006. Vol. 47, nr 2, s. 273-294
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Identifikatorer
URN: urn:nbn:se:su:diva-12570DOI: 10.1140/epjc/s2006-02568-8OAI: oai:DiVA.org:su-12570DiVA, id: diva2:179090
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