Two aspects of one loop structure: Unitarity delay in the Standard Model and modular invariance in string theory

Technical Report · Tue Aug 01 04:00:00 EDT 1989

DOI:https://doi.org/10.2172/5580440· OSTI ID:5580440

Ahn, C

We study two aspects of one loop structures in quantum field theories which describe two different areas of particle physics: the one loop unitarity behavior of the Standard Model of electroweak interactions and modular invariance of string model theory. Loop expansion has its importance in that it contains quantum fluctuations due to all physical states in the theory. Therefore, by studying the various models to one loop, we can understand how the contents of the theory can contribute to physically measurable quantities and how the consistency at quantum level restricts the physical states of the theory, as well. In the first half of the thesis, we study one loop corrections to the process {ital e}{sup +}{ital e}{sup {minus}} {yields} {ital W}{sup +}{ital W}{sup {minus}}. In this process, there is a delicate unitarity-saving cancellation between s-channel and t-channel tree level Feynman diagrams. If the one loop contribution due to heavy particles corrects the channels asymmetrically, the cancellation, hence unitarity, will be delayed up to the mass scale of these heavy particles. We refer to this phenomena as the unitarity delay effect. Due to this effect, cross section below these mass scales can have significant radiative corrections which may provide an appropriate window through which we can see the high energy structure of the Standard Model from relatively low energy experiments. In the second half, we will show how quantum consistency can restrict the physical states in string theory. 53 refs., 13 figs.

• Research Organization: Stanford Linear Accelerator Center, Menlo Park, CA (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: AC03-76SF00515
• OSTI ID: 5580440
• Report Number(s): SLAC-349; ON: DE90000889
• Country of Publication: United States
• Language: English

Related Subjects

645203 -- High Energy Physics-- Particle Interactions & Properties-Theoretical-- Weak Interactions & Properties
645400* -- High Energy Physics-- Field Theory
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BOSONS
COMPOSITE MODELS
CORRECTIONS
CROSS SECTIONS
DIAGRAMS
ELECTRON-POSITRON INTERACTIONS
ELEMENTARY PARTICLES
EXTENDED PARTICLE MODEL
FEYNMAN DIAGRAM
FUNCTIONS
INTERACTIONS
INTERMEDIATE BOSONS
INTERMEDIATE VECTOR BOSONS
LEPTON-LEPTON INTERACTIONS
MATHEMATICAL MODELS
MATHEMATICAL SPACE
PARTICLE INTERACTIONS
PARTICLE MODELS
PARTITION FUNCTIONS
QUARK MODEL
RADIATIVE CORRECTIONS
RIEMANN SPACE
SPACE
STANDARD MODEL
STRING MODELS
SUPERSYMMETRY
SYMMETRY
UNIFIED GAUGE MODELS
W MINUS BOSONS
W PLUS BOSONS