CLEAN PRECISION TESTS OF THE ELECTROWEAK THEORY

1992 ◽  
Vol 07 (12) ◽  
pp. 1009-1021 ◽  
Author(s):  
ZENRŌ HIOKI
Keyword(s):  
Experimental Data ◽  
Top Quark ◽  
Higgs Mass ◽  
Quantum Correction ◽  
Electroweak Theory ◽  
Weak Boson ◽  
Yukawa Couplings ◽  
Symmetry Breakdown ◽  
Electroweak Precision ◽  
Spontaneous Symmetry Breakdown

Present status of electroweak precision tests via the weak boson masses is reviewed, emphasizing that the standard SU(2) × U(1) theory is phenomenologically very successful also at quantum correction level. In particular, it is shown that the latest experimental data indicate the existence not only of the whole one-loop corrections but also of the non-decoupling top-quark effects, independent of the Higgs mass, which are a characteristic feature of theories with masses generated by spontaneous symmetry breakdown plus large Yukawa couplings.

scholarly journals STUDYING STRUCTURE OF ELECTROWEAK CORRECTIONS

1995 ◽  
Vol 10 (26) ◽  
pp. 3803-3815 ◽  
Author(s):  
ZENRŌ HIOKI
Keyword(s):  
Top Quark ◽  
Confidence Level ◽  
Born Approximation ◽  
Higgs Mass ◽  
New Physics ◽  
The Other ◽  
Precision Measurements ◽  
Quantum Corrections ◽  
Electroweak Theory ◽  
Weak Boson

Several different effects in electroweak quantum corrections are explored separately through the latest data on the weak-boson masses. The leading-log approximation, the improved-Born approximation and the nondecoupling top-quark effects are studied without depending on the recent CDF data about mt, and the results are given in a form independent, of the Higgs mass. On the other hand, the bosonic and the nondecoupling Higgs effects are examined by fully taking account of those CDF data. It is emphasized that future precision measurements of MW and mt are considerably significant not only for further studies of the electroweak theory at higher confidence level but also for new-physics searches beyond it.

scholarly journals Prediction of the Higgs and Top Quark Masses by Discrete Dimensions Revisited

2020 ◽  
Vol 36 (2) ◽  
Author(s):  
Nguyen Van Dat ◽  
Nguyen Ai Viet ◽  
Pham Tien Du
Keyword(s):  
Experimental Data ◽  
Top Quark ◽  
Extra Dimension ◽  
Higgs Mass ◽  
New Model ◽  
Quark Masses ◽  
New Knowledge ◽  
Klein Theory ◽  
Kaluza Klein

A new metric structure of the discretized Kaluza-Klein theory can give us new knowledge about extra-dimension . It can provide the new predictions of the top quark and Higgs mass that studied by Viet [15 , 16] in another model. Compare the results of two approaches we can see that the new model is more agreement with experimental data.

AN ALTERNATIVE IMPLEMENTATION OF T-PARITY IN FERMION SECTOR AND THE CHANNEL $VV\to h\to\tau\bar{\tau}$ AT LHC

2011 ◽  
Vol 26 (27) ◽  
pp. 2079-2089 ◽  
Author(s):  
XIAO-FANG HAN ◽  
LEI WANG ◽  
FENG ZHANG
Keyword(s):  
Production Process ◽  
Top Quark ◽  
Higgs Mass ◽  
Higgs Production ◽  
Little Higgs ◽  
Yukawa Couplings

We modify the implementation of T-parity in the fermion sector (called LHT-III), where the mixing of top quark and T-even partner can be absent, and the Higgs mass quadratic divergence contributed by the top quark and a T-odd partner cancel each other. Besides, the Yukawa couplings of down-type quarks and leptons can be enhanced in this model, while these couplings are suppressed in other little Higgs models. Finally, we study the channel [Formula: see text] at LHC in several typical little Higgs models, and find that the rate in all these little Higgs models can have a sizable deviation from the SM prediction, especially for that the rate can only be enhanced in LHT-III, but suppressed in other little Higgs models. Therefore, the Higgs production process [Formula: see text] at LHC can provide a powerful way to probe these little Higgs models, especially for distinguishing the LHT-III from other little Higgs models.

scholarly journals IS THE STANDARD ELECTROWEAK THEORY HAPPY WITH mt~174 GeV?

1995 ◽  
Vol 10 (02) ◽  
pp. 121-124
Author(s):  
ZENRŌ HIOKI ◽  
RYUICHI NAJIMA
Keyword(s):  
Top Quark ◽  
Higgs Mass ◽  
New Physics ◽  
Electroweak Theory ◽  
The Future ◽  
Minimal Standard

Stimulated by the recent CDF report on the top quark, we have carried out an analysis on the Higgs mass within the minimal standard electroweak theory using the latest data on the W-mass. Although this theory is in quite a happy situation now, we wish to point out that more precise measurements of MW and mt in the future are crucial and they could come to require some new physics beyond it.

scholarly journals Neutrino masses, vacuum stability and quantum gravity prediction for the mass of the top quark

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Guillem Domènech ◽  
Mark Goodsell ◽  
Christof Wetterich
Keyword(s):  
Quantum Gravity ◽  
Top Quark ◽  
Quark Mass ◽  
Scalar Potential ◽  
Planck Scale ◽  
Neutrino Masses ◽  
Top Quark Mass ◽  
Vacuum Stability ◽  
Intermediate Scale ◽  
Yukawa Couplings

Abstract A general prediction from asymptotically safe quantum gravity is the approximate vanishing of all quartic scalar couplings at the UV fixed point beyond the Planck scale. A vanishing Higgs doublet quartic coupling near the Planck scale translates into a prediction for the ratio between the mass of the Higgs boson MH and the top quark Mt. If only the standard model particles contribute to the running of couplings below the Planck mass, the observed MH∼ 125 GeV results in the prediction for the top quark mass Mt∼ 171 GeV, in agreement with recent measurements. In this work, we study how the asymptotic safety prediction for the top quark mass is affected by possible physics at an intermediate scale. We investigate the effect of an SU(2) triplet scalar and right-handed neutrinos, needed to explain the tiny mass of left-handed neutrinos. For pure seesaw II, with no or very heavy right handed neutrinos, the top mass can increase to Mt ∼ 172.5 GeV for a triplet mass of M∆ ∼ 108GeV. Right handed neutrino masses at an intermediate scale increase the uncertainty of the predictions of Mt due to unknown Yukawa couplings of the right-handed neutrinos and a cubic interaction in the scalar potential. For an appropriate range of Yukawa couplings there is no longer an issue of vacuum stability.

scholarly journals Mass Reconstruction of MSSM Higgs Boson

2019 ◽  
Vol 64 (8) ◽  
pp. 714
Author(s):  
T. V. Obikhod ◽  
I. A. Petrenko
Keyword(s):  
Experimental Data ◽  
Higgs Boson ◽  
Standard Model ◽  
Top Quark ◽  
Computer Programs ◽  
Higgs Bosons ◽  
Associated Production ◽  
The Standard Model ◽  
The Masses ◽  
Mass Reconstruction

The problems of the Standard Model, as well as questions related to Higgs boson properties led to the need to model the ttH associated production and the Higgs boson decay to a top quark pair within the MSSM model. With the help of computer programs MadGraph, Pythia, and Delphes and using the latest kinematic cuts taken from experimental data obtained at the LHC, we have predicted the masses of MSSM Higgs bosons, A and H.

scholarly journals THE GAUGE HIERARCHY PROBLEM AND HIGHER-DIMENSIONAL GAUGE THEORIES

1998 ◽  
Vol 13 (32) ◽  
pp. 2601-2611 ◽  
Author(s):  
HISAKI HATANAKA ◽  
TAKEO INAMI ◽  
C. S. LIM
Keyword(s):  
Higgs Mass ◽  
Quantum Correction ◽  
Gauge Theories ◽  
Finite Mass ◽  
Hierarchy Problem ◽  
Mass Correction ◽  
Higher Dimensional ◽  
Gauge Hierarchy ◽  
Simply Connected ◽  
Matter Fields

We report on an attempt to solve the gauge hierarchy problem in the framework of higher-dimensional gauge theories. Both classical Higgs mass and quadratically divergent quantum correction to the mass are argued to be vanished. Hence the hierarchy problem in its original sense is solved. The remaining finite mass correction is shown to depend crucially on the choice of boundary condition for matter fields, and a way to fix it dynamically is presented. We also point out that on the simply-connected space S2 even the finite mass correction vanishes.

scholarly journals BRST QUANTIZATION OF SU(2/1) ELECTROWEAK THEORY IN THE SUPERCONNECTION APPROACH, AND THE HIGGS MESON MASS

1996 ◽  
Vol 11 (19) ◽  
pp. 3509-3522 ◽  
Author(s):  
DAE SUNG HWANG ◽  
CHANG-YEONG LEE ◽  
YUVAL NE’EMAN
Keyword(s):  
Renormalization Group ◽  
Top Quark ◽  
Brst Quantization ◽  
Higgs Field ◽  
Mass Term ◽  
Scalar Fields ◽  
Meson Mass ◽  
Electroweak Theory ◽  
Renormalization Group Equations ◽  
Brst Invariance

A superconnection, in which a scalar field enters as a zero-form in the odd part of the superalgebra, is used in the BRST quantization of the SU (2/1) “internally superunified” electroweak theory. A quantum action is obtained, by applying symmetric BRST/anti-BRST invariance. Evaluating the mass of the Higgs field, we exhibit the consistency between two approaches: (a) applying the supergroup’s (gauge) value for λ, the coupling of the scalar field’s quartic potential, to the conventional (spontaneous symmetry breakdown) evaluation; (b) dealing with the superconnection components as a supermultiplet of an (global) internal supersymmetry. This result thus provides a general foundation for the use of “internal” supergauges. With SU (2/1) broken by the negative squared mass term for the Higgs field and with the matter supermultiplets involving added “effective” ghost states, there is no reason to expect the symmetry’s couplings not to be renormalized. This explains the small difference between predicted and measured values for sin2θw, namely the other coupling fixed by SU (2/1) beyond the Standard Model’s SU(2)×U(1), and where the experimental results are very precise. Using the renormalization group equations and those experimental data, we thus evaluate the energy E8 at which the SU (2/1) predicted value of 0.25 is expected to correspond to the experimental values. With SU (2/1) precise at that energy Es=5 TeV , we then apply the renormalization group equations again, this time to evaluate the corrections to the above λ, the quartic coupling of the scalar fields; as a result we obtain corrections to the prediction for the Higgs meson’s mass. Our result predicts the Higgs’ mass [170 GeV, according to unrenormalized SU (2/1)] to be as low as 130±6 GeV , using for the top quark mass the recently measured value of 174 GeV .

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