Analysis of angular observables of Lambda(b) -> Lambda (-> p pi) mu(+)mu(-) decay in the standard and Z ' models

doi:10.1093/ptep/pty043

	Analysis of angular observables of Lambda(b) -> Lambda (-> p pi) mu(+)mu(-) decay in the standard and Z ' models
	Nasrullah, A; Aslam, MJ; Shafaq, S
刊名	PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS
	2018
期号	4 页码:043B08
ISSN号	2050-3911
DOI	10.1093/ptep/pty043
文献子类	Article
英文摘要	In 2015, the LHCb collaboration measured the differential branching ratio dB/dq(2), the lepton- and hadron-side forward-backward asymmetries, denoted by A(FB)(l) and A(FB)(Lambda), respectively, in the range 15 < q(2)(= s) < 20 GeV2 with 3 fb(-1) of data. Motivated by these measurements, we perform an analysis of q(2)-dependent Lambda(b) -> Lambda (-> p pi) mu(+)mu(-) angular observables at large-and low-recoil in the standard model ( SM) and in a family non-universal Z' model. The exclusive Lambda(b) -> Lambda transition is governed by the form factors, and in the present study we use the recently performed high-precision lattice QCD calculations that have well-controlled uncertainties, especially in the 15 < s < 20 GeV2 bin. Using the full four-folded angular distribution of Lambda(b) -> Lambda (-> p pi) mu(+)mu(-) decay, first of all we focus on calculations of the experimentally measured dB/ds, A(FB)(l), and AFB(Lambda) in the SM and compare their numerical values with the measurements in appropriate bins of s. In case of a possible discrepancy between the SM prediction and the measurements, we try to see if these can be accommodated though the extra neutral Z' boson. We find that in the dimuon momentum range 15 < s < 20 GeV2 the value of dB/ds and central value of AFB(l) in the Z' model is compatible with the measured values. In addition, the fraction of longitudinal polarization of the dimuon F-L was measured to be 0.61(-0.14)(-0.11) +/- 0.03 in 15 < s < 20 GeV2 at the LHCb. We find that in this bin the value found in the Z' model is close to the observed values. After comparing the results of these observables, we have proposed other observables such as alpha(i) and alpha(('))(i) with i = theta(l), theta(Lambda), phi, L, U and coefficients of different foldings P-1,P-...,P-9 in different bins of s in the SM and Z' model. We illustrate that the experimental observations of the s-dependent angular observables calculated here in several bins of s can help to test the predictions of the SM and unravel new physics contributions arising due to the Z' model in Lambda(b) -> Lambda (-> p pi) mu(+)mu(-) decays.
WOS关键词	CHANGING NEUTRAL CURRENTS ; DOUBLE-LEPTON POLARIZATION ; LAMBDA-L(+)L(-) DECAY ; B-S ; PENGUIN DECAYS ; LEPTOPHOBIC Z' ; HEAVY BARYONS ; K DECAYS ; FLAVOR ; CONSTRAINTS
WOS研究方向	Physics
语种	英语
WOS记录号	WOS:000431146800002
内容类型	期刊论文
源URL	[http://ir.ihep.ac.cn/handle/311005/287023]
专题	高能物理研究所_理论物理室
通讯作者	Aslam, MJ
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	Nasrullah, A,Aslam, MJ,Shafaq, S. Analysis of angular observables of Lambda(b) -> Lambda (-> p pi) mu(+)mu(-) decay in the standard and Z ' models[J]. PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS,2018(4):043B08.
APA	Nasrullah, A,Aslam, MJ,&Shafaq, S.(2018).Analysis of angular observables of Lambda(b) -> Lambda (-> p pi) mu(+)mu(-) decay in the standard and Z ' models.PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS(4),043B08.
MLA	Nasrullah, A,et al."Analysis of angular observables of Lambda(b) -> Lambda (-> p pi) mu(+)mu(-) decay in the standard and Z ' models".PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS .4(2018):043B08.