Observation of the muon inner bremsstrahlung at LEP1
Observation of the muon inner bremsstrahlung at LEP1
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LEP1 处 μ 子内轫致辐射的观测
DOI：
10.1140/epjc/s10052-008-0779-z
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
et al.
中科院分区：
文献类型：
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作者：
T. D. C. J. Abdallah;et al.
研究了LEP 1双μ子事例中在德尔菲主跟踪器（TPC）前转换的μ子韧致辐射光子在两个光子运动学范围内的变化：0.2<Eγ≤ 1GeV和相对于母μ子的横向动量pT<40 MeV/c，以及1<Eγ≤10 GeV和pT<80 MeV/c.一个很好的协议所观察到的光子速率与QED预测的μ子内韧致辐射被发现，相反的反常的软光子过剩，最近已经观察到的强子Z 0衰变。在0.2<Eγ≤ 1GeV和1<Eγ≤10 GeV的光子能量范围内，观测到的μ子韧致辐射信号与预测值的比值分别为1.06±0.12±0.07和1.04±0.09±0.12。首次在LEP的直接光子产生中观察到韧致辐射死锥。
Muon bremsstrahlung photons converted in front of the DELPHI main tracker (TPC) in dimuon events at LEP1 were studied in two photon kinematic ranges: 0.2<Eγ≤1 GeV and transverse momentum with respect to the parent muon pT<40 MeV/c, and 1<Eγ≤10 GeV and pT<80 MeV/c. A good agreement of the observed photon rate with predictions from QED for the muon inner bremsstrahlung was found, contrary to the anomalous soft photon excess that has been observed recently in hadronic Z0 decays. The obtained ratios of the observed signal to the predicted level of the muon bremsstrahlung are 1.06±0.12±0.07 in the photon energy range 0.2<Eγ≤1 GeV and 1.04±0.09±0.12 in the photon energy range 1<Eγ≤10 GeV. The bremsstrahlung dead cone is observed for the first time in the direct photon production at LEP.