Constraints on additional Z bosons

Journal Article · Tue Dec 31 23:00:00 EST 1991 · Physical Review, D (Particles Fields); (United States)

DOI:https://doi.org/10.1103/PhysRevD.45.278· OSTI ID:5084430

Langacker, P; Luo, M ^[1]

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1. University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)

{ital Z}-pole, {ital W}-mass, and weak neutral-current (WNC) data as well as direct collider limits are used to constrain the mass and mixing of possible heavy {ital Z}{sub 2} bosons with couplings expected in grand unified theories and SU(2){sub {ital L}}{times}SU(2){sub {ital R}}{times}U(1) models. The data now enable the top-quark mass and {ital Z}{sub 2} properties to be limited simultaneously. The indirect ({ital Z}-pole, {ital M}{sub {ital W}}, WNC) data stringently constrain the {ital Z}{sub 1}{sup 0-}{ital Z}{sub 2}{sup 0} mixing angle {theta} ({vert bar}{theta}{vert bar}{lt}0.01 in most cases). For models with arbitrary Higgs representations, the limits on the {ital Z}{sub 2} mass {ital M}{sub 2} from indirect and direct constraints are rather weak (typically 160--400 GeV), but in specific models in which {ital M}{sub 2} and {theta} are correlated, the constraints are much stronger ({ital M}{sub 2}{gt}500--1000 GeV). The weak angle in the modified minimal subtraction scheme is well determined even allowing for extra {ital Z}'s and an arbitrary Higgs structure: sin{sup 2}{cflx {theta}}{sub {ital W}}({ital M}{sub {ital Z}})=0.2334{sub {minus}0.0011}{sup +0.0008}, for the models considered, where the uncertainties include {ital m}{sub {ital t}}, compared to the SU(2){times}U(1) model value 0.2333{plus minus}0.0008. The 95%-C.L. upper limits on {ital m}{sub {ital t}} ({ital m}{sub {ital t}}{lt}182 GeV for Higgs doublets and singlets only, and {ital m}{sub {ital t}}{lt}310 GeV for arbitrary Higgs representations) continue to hold in the presence of the extra {ital Z}'s considered. The implications of these results for ordinary and supersymmetric grand unification, atomic parity violation, charged-current universality, {ital R}({ital e}{sup +}{ital e{minus}}{r arrow}{mu}{sup +}{mu}{sup {minus}}, hadrons) below the {ital Z} pole, and superstring theories are discussed.

• DOE Contract Number: AC02-76ER03071
• OSTI ID: 5084430
• Journal Information: Physical Review, D (Particles Fields); (United States), Journal Name: Physical Review, D (Particles Fields); (United States) Vol. 45:1; ISSN PRVDA; ISSN 0556-2821
• Country of Publication: United States
• Language: English

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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ALGEBRAIC CURRENTS
ATOMS
BOSONS
BRANCHING RATIO
COMPOSITE MODELS
COUPLING CONSTANTS
CURRENTS
ELECTRON-POSITRON INTERACTIONS
ELEMENTARY PARTICLES
EXTENDED PARTICLE MODEL
FIELD THEORIES
GRAND UNIFIED THEORY
HIGGS MODEL
INTERACTIONS
INTERMEDIATE BOSONS
INTERMEDIATE VECTOR BOSONS
INVARIANCE PRINCIPLES
LEPTON-LEPTON INTERACTIONS
LIE GROUPS
MASS
MATHEMATICAL MODELS
NEUTRAL CURRENTS
P INVARIANCE
PARTICLE INTERACTIONS
PARTICLE MODELS
QUARK MODEL
STANDARD MODEL
STRING MODELS
SU GROUPS
SU-2 GROUPS
SUPERSYMMETRY
SYMMETRY
SYMMETRY GROUPS
U GROUPS
U-1 GROUPS
UNIFIED GAUGE MODELS
UNIFIED-FIELD THEORIES
WEAK NEUTRAL CURRENTS
Z NEUTRAL BOSONS