Study of the heavy-lepton decay tau. --> nu. 3. pi

Journal Article · Fri Jan 01 04:00:00 EST 1982 · Phys. Rev. D; (United States)

DOI:https://doi.org/10.1103/PhysRevD.25.149· OSTI ID:5839046

Brehm, J J

A construction is made of the hadronic matrix element of the axialvector current <3..pi..Vertical BarA/sub lambda/Vertical Bar0> which enters in the amplitude for the decay tau..--> nu..+3..pi... The matrix element has 1/sup +/ and 0/sup -/ parts, and both are expanded in terms of three-body p..pi.. and epsilon..pi.. isobar channels. A modular picture of the process has evolved in which one module described the effects of rearrangement in 3..pi.. states having these quantum numbers while the other module pertains to the origin of the 3..pi.. system and is peculiar to the process at hand. The first factor has been calculated in a previous paper and exhibits a noteworthy 1/sup +/ enhancement effect at 1.1 GeV. The second factor is modeled here in detail and is shown to be fully parametrizable by using the methods of hard-pion current algebra; its 1/sup +/ part is presumed to be dominated by the A/sub 1/ resonance. The entire composition contains only three parameters, two of which are the mass and width of the A/sub 1/, m/sub A/, and GAMMA/sub A/. As such it provides a suitable means of examining tau..--> nu..3..pi.. phenomenology in the presence of several interesting effects and may be employed in conjunction with suitably refined data in order to obtain the values of m/sub A/ and GAMMA/sub A/. The meager experimental data currently available are shown to suggest tentative values of these parameters around m/sub A/ = 1.10 GeV and GAMMA/sub A/ = 0.45 GeV. The 1/sup +/ enhancement effect due to final-state rearrangement is assessed relative to the effect of the resonance alone and the extent to which it acts as a peak shifter or peak sharpener is evaluated. Finally, attention is drawn to the possible need for special care and interest in handling the generally neglected 0/sup -/ state, in view of recent results from diffraction experiments in the pseudoscalar 3..pi.. channel.

• Research Organization: Department of Physics and Astronomy, University of Massachusetts, Amherst, Massachusetts 01003
• OSTI ID: 5839046
• Journal Information: Phys. Rev. D; (United States), Journal Name: Phys. Rev. D; (United States) Vol. 25:1; ISSN PRVDA
• Country of Publication: United States
• Language: English

Related Subjects

645203* -- High Energy Physics-- Particle Interactions &amp; Properties-Theoretical-- Weak Interactions &amp; Properties
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ALGEBRAIC CURRENTS
ANGULAR MOMENTUM
AXIAL-VECTOR CURRENTS
BOSONS
CURRENTS
DECAY
ELEMENTARY PARTICLES
FERMIONS
HADRONS
HEAVY LEPTONS
ISOBAR MODEL
LEPTONS
MANY-BODY PROBLEM
MASSLESS PARTICLES
MATHEMATICAL MODELS
MATRIX ELEMENTS
MESONS
NEUTRINOS
PARITY
PARTICLE DECAY
PARTICLE MODELS
PARTICLE PROPERTIES
PHASE SHIFT
PIONS
POSTULATED PARTICLES
PSEUDOSCALAR MESONS
QUANTUM NUMBERS
SEMILEPTONIC DECAY
THREE-BODY PROBLEM
WEAK PARTICLE DECAY