Test for maximal P , maximal C violation in e sup minus e+ collisions from beam-referenced spin-correlation functions

Journal Article · Thu Feb 28 23:00:00 EST 1991 · Physical Review, D (Particles Fields); (USA)

DOI:https://doi.org/10.1103/PhysRevD.43.1465· OSTI ID:6044233

Nelson, C A ^[1]

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1. Department of Physics, State University of New York, Binghamton, New York 13902-6000 (US)

For unpolarized beams in {ital e}{sup {minus}}{ital e+} collisions at the {ital Z}{sup 0}, beam-referenced spin-correlation functions for the production-decay sequence {ital e}{sup {minus}}{ital e+}{r arrow}{ital Z}{sup 0}{r arrow}{tau}{sub 1}{sup {minus}}{tau}{sub 2}{sup +}{r arrow}({ital h}{sub 1}{sup {minus}}{nu})({ital h}{sub 2}{sup +}{bar {nu}}) can be easily derived using the helicity approach. For {tau}{sub 1}{sup {minus}}{r arrow}{pi}{sub 1}{sup {minus}}{nu}, for example, this reaction is analyzed relative to the final {pi}{sup {minus}} momentum vector. The most interesting result is an azimuthal correlation function {ital I}({phi}{sub {ital e}},{phi}) where the azimuthal angles are defined relative to the final {pi}{sub 1}{sup {minus}}. {ital I}({phi}{sub {ital e}},{phi}) allows one to simply test for maximal {ital P}, maximal {ital C} violation in the {ital Z}{sup 0}{r arrow}{tau}{sub 1}{sup {minus}}{tau}{sub 1}{sup +} coupling. For {ital e}{sup {minus}}{ital e+} collisions in the {Upsilon} or {ital J}/{psi} regions, {ital I}({phi}{sub {ital e}},{phi}) can be used to test for a complex phase in the {gamma}{sup *}{r arrow}{tau}{sup {minus}}{tau}{sup +} coupling. Previously it was shown that the measurement of the energy correlation function {ital I}({ital E}{sub {ital A}},{ital E}{sub {ital B}}) for {ital Z}{sup 0}{r arrow}{tau}{sub 1}{sup {minus}}{tau}{sub 1}{sup +}{r arrow}{ital A}{sup {minus}}{ital B+}{ital X} determines independently the fundamental parameters sin{sup 2}{theta}{sub {ital W}}, the {tau} Michel parameters, and for hadronic {tau} decays the analogous chirality parameter {xi}{sub {ital A}} which tests for right-handed currents. Now by referencing this energy correlation function to the incident {ital e}{sup {minus}} beam direction, the associated ideal statistical errors for these parameters for the case of hadronic {tau} decays are reduced only by about 25%.

• DOE Contract Number: FG02-86ER40291
• OSTI ID: 6044233
• Journal Information: Physical Review, D (Particles Fields); (USA), Journal Name: Physical Review, D (Particles Fields); (USA) Vol. 43:5; ISSN PRVDA; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

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645203 -- High Energy Physics-- Particle Interactions & Properties-Theoretical-- Weak Interactions & Properties
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANGULAR DISTRIBUTION
ANGULAR MOMENTUM
ANNIHILATION
BASIC INTERACTIONS
BOSONS
C INVARIANCE
CORRELATION FUNCTIONS
COUPLING
DECAY
DISTRIBUTION
ELECTROMAGNETIC INTERACTIONS
ELECTRON-POSITRON INTERACTIONS
ELEMENTARY PARTICLES
FERMIONS
FUNCTIONS
HEAVY LEPTONS
HELICITY
INTERACTIONS
INTERMEDIATE BOSONS
INTERMEDIATE VECTOR BOSONS
INVARIANCE PRINCIPLES
LEPTON-LEPTON INTERACTIONS
LEPTONS
MATHEMATICAL MODELS
PARTICLE INTERACTIONS
PARTICLE PRODUCTION
PARTICLE PROPERTIES
POSTULATED PARTICLES
SPIN
STATISTICAL MODELS
TAU PARTICLES
TESTING
Z NEUTRAL BOSONS