New Measurement of the π0 radiative decay width.
New Measurement of the π0 radiative decay width.
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π0 辐射衰减宽度的新测量。
DOI：
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发表时间：
2010
影响因子：
8.6
通讯作者：
R. Pedroni
中科院分区：
文献类型：
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作者：
I. Larin;D. Mcnulty;Y. Prok;A. Bernstein;S. Kowalski;E. Clinton;P. Martel;R. Miskimen;M. Wood;P. Ambrozewicz;A. Ahmidouch;L. Benton;S. Danagoulian;R. Demirchyan;A. Gasparian;K. Hardy;S. Mtingwa;Steven Overby;M. Payen;R. Pedroni
已经对 12C 和 208Pb 两个原子核在正向角下的 π0 光产生的微分截面进行了高精度测量，入射光子能量为 4.9-5.5 GeV，以提取 π0→γγ 衰变宽度。该实验是在杰斐逊实验室使用 Hall B 光子标记器和高分辨率多通道量热计完成的。 π0→γγ 衰减宽度是通过使用最近更新的过程理论模型拟合测量的横截面来提取的。衰减宽度的结果值为 Γ(π0→γγ)=7.82±0.14(stat)±0.17(syst) eV。总不确定度为 2.8%，该结果比当前粒子数据组对该基本量的平均值精确了 2.5 倍，与当前的理论预测一致。
High precision measurements of the differential cross sections for π0 photoproduction at forward angles for two nuclei, 12C and 208Pb, have been performed for incident photon energies of 4.9-5.5 GeV to extract the π0→γγ decay width. The experiment was done at Jefferson Lab using the Hall B photon tagger and a high-resolution multichannel calorimeter. The π0→γγ decay width was extracted by fitting the measured cross sections using recently updated theoretical models for the process. The resulting value for the decay width is Γ(π0→γγ)=7.82±0.14(stat)±0.17(syst) eV. With the 2.8% total uncertainty, this result is a factor of 2.5 more precise than the current Particle Data Group average of this fundamental quantity, and it is consistent with current theoretical predictions.