Difference in direct charge-parity violation between charged and neutral B meson decays

	Difference in direct charge-parity violation between charged and neutral B meson decays
	Belle Collaboration
刊名	NATURE
	2008
卷号	452 期号:7185 页码:332-335
关键词	DIRECT CP VIOLATION ASYMMETRIES BELLE
通讯作者	Chang, P (reprint author), Natl Taiwan Univ, Dept Phys, Taipei 106, Taiwan.
英文摘要	Equal amounts of matter and antimatter are predicted to have been produced in the Big Bang, but our observable Universe is clearly matter- dominated. One of the prerequisites(1) for understanding this elimination of antimatter is the nonconservation of charge- parity ( CP) symmetry. So far, two types of CP violation have been observed in the neutral K meson ( K-0) and B meson ( B-0) systems: CP violation involving the mixing(2) between K-0 and its antiparticle (K) over bar (0) ( and likewise(3,4) for B-0 and (B) over bar (0)), and direct CP violation in the decay of each meson(5-8). The observed effects for both types of CP violation are substantially larger for the B-0 meson system. However, they are still consistent with the standard model of particle physics, which has a unique source(9) of CP violation that is known to be too small(10) to account for the matter-dominated Universe. Here we report that the direct CP violation in charged B-+/- --> K-+/- pi(0) decay is different from that in the neutral B-0 counterpart. The direct CP- violating decay rate asymmetry, A(K)+/- (pi 0) ( that is, the difference between the number of observed B- --> K- pi(0) event versus B+ --> K+ pi(0) events, normalized to the sum of these events) is measured to be about +7%, with an uncertainty that is reduced by a factor of 1.7 from a previous measurement(7). However, the asymmetry A(K+/-) p(-/+) for B-0 --> K- pi(+) versus B-0 --> K+ pi(-) is at the -10% level(7,8). Although it is susceptible to strong interaction effects that need further clarification, this large deviation in direct CP violation between charged and neutral B meson decays could be an indication of new sources of CP violation - which would help to explain the dominance of matter in the Universe.
学科主题	Science & Technology - Other Topics
类目[WOS]	Multidisciplinary Sciences
收录类别	SCI
语种	英语
WOS记录号	WOS:000254117400042
公开日期	2016-02-26
内容类型	期刊论文
源URL	[http://ir.ihep.ac.cn/handle/311005/212843]
专题	高能物理研究所_实验物理中心
作者单位	中国科学院高能物理研究所
推荐引用方式 GB/T 7714	Belle Collaboration. Difference in direct charge-parity violation between charged and neutral B meson decays[J]. NATURE,2008,452(7185):332-335.
APA	Belle Collaboration.(2008).Difference in direct charge-parity violation between charged and neutral B meson decays.NATURE,452(7185),332-335.
MLA	Belle Collaboration."Difference in direct charge-parity violation between charged and neutral B meson decays".NATURE 452.7185(2008):332-335.