气候变化领域集成服务门户(CCPortal): Precision measurement of the neutral pion lifetime

CCPortal

DOI	10.1126/science.aay6641
	Precision measurement of the neutral pion lifetime
	Larin I.; Zhang Y.; Gasparian A.; Gan L.; Miskimen R.; Khandaker M.; Dale D.; Danagoulian S.; Pasyuk E.; Gao H.; Ahmidouch A.; Ambrozewicz P.; Baturin V.; Burkert V.; Clinton E.; Deur A.; Dolgolenko A.; Dutta D.; Fedotov G.; Feng J.; Gevorkyan S.; Glamazdin A.; Guo L.; Isupov E.; Ito M.M.; Klein F.; Kowalski S.; Kubarovsky A.; Kubarovsky V.; Lawrence D.; Lu H.; Ma L.; Matveev V.; Morrison B.; Micherdzinska A.; Nakagawa I.; Park K.; Pedroni R.; Phelps W.; Protopopescu D.; Rimal D.; Romanov D.; Salgado C.; Shahinyan A.; Sober D.; Stepanyan S.; Tarasov V.V.; Taylor S.; Vasiliev A.; Wood M.; Ye L.; Zihlmann B.; PrimEx-II Collaboration
发表日期	2020
ISSN	0036-8075
起始页码	506
结束页码	509
卷号	368 期号:6490
英文摘要	The explicit breaking of the axial symmetry by quantum fluctuations gives rise to the so-called axial anomaly. This phenomenon is solely responsible for the decay of the neutral pion p0 into two photons (gg), leading to its unusually short lifetime. We precisely measured the decay width G of the p0 → gg process. The differential cross sections for p0 photoproduction at forward angles were measured on two targets, carbon-12 and silicon-28, yielding G(p0 → gg) = 7.798 ± 0.056(stat.) ± 0.109(syst.) eV, where stat. denotes the statistical uncertainty and syst. the systematic uncertainty. We combined the results of this and an earlier experiment to generate a weighted average of G(p0 → gg) = 7.802 ± 0.052(stat.) ± 0.105(syst.) eV. Our final result has a total uncertainty of 1.50% and confirms the prediction based on the chiral anomaly in quantum chromodynamics. Copyright © 2020 The Authors,
关键词	carbon silicon silicon 28 unclassified drug asymmetry measurement method precision quantum mechanics Article chirality decay time constant measurement precision negative pi meson photon photosynthesis pion prediction priority journal quantum chromodynamics quantum mechanics
语种	英语
来源机构	Science
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/133526
推荐引用方式 GB/T 7714	Larin I.,Zhang Y.,Gasparian A.,et al. Precision measurement of the neutral pion lifetime[J]. Science,2020,368(6490).
APA	Larin I..,Zhang Y..,Gasparian A..,Gan L..,Miskimen R..,...&PrimEx-II Collaboration.(2020).Precision measurement of the neutral pion lifetime.,368(6490).
MLA	Larin I.,et al."Precision measurement of the neutral pion lifetime".368.6490(2020).