Tests for ''new physics'' from /tau/ spin correlation functions for /ital Z//sup 0//r arrow//tau//sup +//tau//sup /minus///r arrow/A/sup +/B/sup /minus//X

Journal Article · Sat Jul 01 00:00:00 EDT 1989 · Phys. Rev. D; (United States)

DOI:https://doi.org/10.1103/PhysRevD.40.123· OSTI ID:5725484

Nelson, C A

The fundamental parameters /xi//sub /ital A//, /xi//sub /ital B//, and /alpha//sub /ital H// can be independently determined by measurement of the energy correlation function /ital I/(/ital E//sub /ital A//,/ital E//sub /ital B//) where /xi/ is the Michel polarization parameter for /tau//sup /minus///r arrow/scrl/sup /minus///nu//bar /nu//,/xi//sub /ital A//=(/vert bar/g/sub L//vert bar//sup 2//minus//vert bar/g/sub R//vert bar//sup 2/)(/vert bar//ital g//sub /ital L///vert bar//sup 2/+/vert bar/g/sub R//vert bar//sup 2/) is the chiral polarization parameter for /tau//sup /minus///r arrow/A/sup /minus///nu/, and /alpha//sub /ital H///congruent//minus/2a/sub /tau//v/sub /tau///(a/sub /tau///sup 2/+v/sub /tau///sup 2/) where /ital a//sub /tau//, /ital v//sub /tau// describe /ital Z//sup 0//r arrow//tau//sup +//tau//sup /minus// at the tree level. In contrast, measurement of /ital I/(/ital E//sub /ital A//) by the /tau/-polarization technique only determines /xi//sub /ital A///alpha//sub H/. For 10/sup 7/ Z/sup 0/ events and for sin/sup 2//theta//sub W/=0.23, the ideal statistical percentage errors in the determination of the Michel parameters are for /xi/, 2.6%; for /delta/, 3.5%; and for /rho/, 1.0%; and of the chiral parameters are for /xi//sub /pi//, 1.4%; for /xi//sub /rho//, 3.0%; and for /xi//sub /ital K//sup *//, 18%. For /alpha//sub /ital H//, the ideal statistical error is /sigma/(/alpha//sub /ital H//)=0.005 (3.3%). Equivalently, for sin/sup 2//theta//sub W/ it is 0.3%. Explicit formulas for the full sequential decay correlation function /ital I/(/ital E//sub /bar /mu///, /ital E//sub /ital e//, cos/psi//sub /bar /mu///ital e//) are given for arbitrary /ital Z/ mass and for /ital I/(/ital E//sub /bar /mu///, /ital E//sub /ital B//) for arbitrary Michel parameters. These results can be used for analyzing the decay of a /ital Z//prime/ boson and for /ital q/bar q// modes.

• Research Organization: Department of Physics, State University of New York at Binghamton, Binghamton, New York 13901 (US)
• OSTI ID: 5725484
• Journal Information: Phys. Rev. D; (United States), Vol. 40:1
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
Z NEUTRAL BOSONS
DECAY
CORRELATION FUNCTIONS
POLARIZATION
TAU PARTICLES
BOSONS
ELEMENTARY PARTICLES
FERMIONS
FUNCTIONS
HEAVY LEPTONS
INTERMEDIATE BOSONS
INTERMEDIATE VECTOR BOSONS
LEPTONS
POSTULATED PARTICLES
645203* - High Energy Physics- Particle Interactions & Properties-Theoretical- Weak Interactions & Properties