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

Journal Article · Fri Mar 01 00:00:00 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), Vol. 43:5; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ELECTRON-POSITRON INTERACTIONS
ANNIHILATION
Z NEUTRAL BOSONS
DECAY
PARTICLE PRODUCTION
ANGULAR DISTRIBUTION
C INVARIANCE
CORRELATION FUNCTIONS
COUPLING
HELICITY
SPIN
STATISTICAL MODELS
TAU PARTICLES
TESTING
ANGULAR MOMENTUM
BASIC INTERACTIONS
BOSONS
DISTRIBUTION
ELECTROMAGNETIC INTERACTIONS
ELEMENTARY PARTICLES
FERMIONS
FUNCTIONS
HEAVY LEPTONS
INTERACTIONS
INTERMEDIATE BOSONS
INTERMEDIATE VECTOR BOSONS
INVARIANCE PRINCIPLES
LEPTON-LEPTON INTERACTIONS
LEPTONS
MATHEMATICAL MODELS
PARTICLE INTERACTIONS
PARTICLE PROPERTIES
POSTULATED PARTICLES
645202* - High Energy Physics- Particle Interactions & Properties-Theoretical- Electromagnetic Interactions & Properties
645203 - High Energy Physics- Particle Interactions & Properties-Theoretical- Weak Interactions & Properties