Measurement of Lambda polarization from Z decays

	Measurement of Lambda polarization from Z decays
	ALEPH Collaboration
刊名	PHYSICS LETTERS B
	1996
卷号	374 期号:4 页码:#REF!
通讯作者	Buskulic, D (reprint author), INST NATL PHYS NUCL & PHYS PARTICULES, CNRS, PHYS PARTICULES LAB, F-74019 ANNECY LE VIEUX, FRANCE.
英文摘要	The polarization of Lambda baryons from Z decays is studied with the ALEPH apparatus. Evidence of longitudinal polarization of s quarks from Z decay is observed for the first time. The measured longitudinal Lambda polarization is P-L(Lambda) = -0.32 +/- 0.07 for z = p/pbeam > 0.3. This agrees with the prediction of -0.39 +/- 0.08 from the standard model and the constituent quark model, where the error is due to uncertainties in the mechanism for Lambda production. The observed Lambda polarization is diluted with respect to the primary s quark polarization by Lambda baryons without a primary s quark. Measurements of the Lambda forward-backward asymmetry and of the correlation between back-to-back Lambda<(Lambda)over bar> pairs are used to check this dilution. In addition the transverse Lambda polarization is measured. An indication of transverse polarization, more than two standard deviations away from zero, is found along the normal to the plane defined by the thrust axis and the Lambda direction.
学科主题	Physics
类目[WOS]	Physics, Multidisciplinary
收录类别	SCI
WOS记录号	WOS:A1996UM34500007
公开日期	2016-05-03
内容类型	期刊论文
源URL	[http://ir.ihep.ac.cn/handle/311005/227539]
专题	高能物理研究所_实验物理中心
推荐引用方式 GB/T 7714	ALEPH Collaboration. Measurement of Lambda polarization from Z decays[J]. PHYSICS LETTERS B,1996,374(4):#REF!.
APA	ALEPH Collaboration.(1996).Measurement of Lambda polarization from Z decays.PHYSICS LETTERS B,374(4),#REF!.
MLA	ALEPH Collaboration."Measurement of Lambda polarization from Z decays".PHYSICS LETTERS B 374.4(1996):#REF!.