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.

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 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.

LITTLE HIGGS MODELS FOR NON-UNIVERSALITY FERMION

2005 ◽  
Vol 20 (21) ◽  
pp. 1589-1603
Author(s):  
YAN CHAI ◽  
FURONG YIN
Keyword(s):  
Higgs Mass ◽  
Little Higgs ◽  
Gauge Bosons ◽  
New Models ◽  
The One

We introduce the fermion non-universality into the little Higgs models SU (5)/ SO (5), SU (6)/ Sp (6) and study the phenomenology of the new models. We find that if we change the transform property of the observed fermions under the extended [ SU (2)× U (1)]2, the cancellation of the one-loop quadratically divergent correction to the Higgs mass arising from gauge bosons will not be changed, whereas the phenomenology at W-pole, Z-pole and low q2 will be changed.

THE HIGGS PHENOMENON

1996 ◽  
Vol 11 (27) ◽  
pp. 4779-4783 ◽  
Author(s):  
RUDOLF RODENBERG
Keyword(s):  
Top Quark ◽  
Quantum Coherence ◽  
Higgs Mass ◽  
Scalar Fields ◽  
Scale Dependence ◽  
Multiple Point ◽  
Higgs Particle ◽  
Theoretical Methods ◽  
Low Energies ◽  
Nonlinear Realizations

We briefly discuss why we are forced to use the Higgs–Kibble mechanism just, for example, to be able to "present" masses and what in this sense the so-called Higgs phenomenon really means. But, independent of this fact that we cannot calculate physical masses, we, in spite of this reality, briefly demonstrate presently available theoretical methods for understanding the top-Higgs-mass correlations, for example, especially since the discovery of the top quark at FNAL. It is possible that model-dependent ways, using SUSY and SUGRA models, for example, to overcome the so-called scale dependence (just from the Planck down to the Fermi scale), nonlinear realizations of SUSY and also the requirement of phase coexistence of the two minima of the effective potential with one-loop corrections and its degeneracy ("multiple point criticality principle"), might indicate that in this sense the existence of supersymmetry can be "partially" ruled out. In this context the top-Higgs-mass spectrum belongs neither to the SM nor to SUSY. Also, the loss of quantum coherence, which is very small at low energies for everything except scalar fields, leads to the prediction that we may never observe the Higgs particle either.

scholarly journals CONSTRAINTS ON THE ELECTROWEAK UNIVERSAL PARAMETERS AND THE TOP AND HIGGS MASSES FROM UPDATED LEP/SLC DATA

1995 ◽  
Vol 10 (33) ◽  
pp. 2553-2569 ◽  
Author(s):  
SEIJI MATSUMOTO
Keyword(s):  
Form Factor ◽  
Higgs Boson ◽  
Top Quark ◽  
Higgs Mass ◽  
Global Analysis ◽  
Mean Value ◽  
The Standard Model ◽  
The Mean ◽  
The Masses ◽  
Vertex Form Factor

A global analysis is performed using the recent data from LEP and SLC. Constraints on the electroweak universal parameters (S, T, U) and on the masses of the top quark and Higgs boson within the standard model (SM) are investigated. The uncertainties due to the QCD and QED effective couplings, αs(mz) and , [Formula: see text] are examined in detail. Even though the mean value of S is increased to be consistent with zero, the naive Technicolor models are still disfavored due to its reduced error. Within the SM, we find the 90% CL constraints; 133 GeV<mt<190 GeV and 10 GeV<mH< 440 GeV for αs(mz)=0.116 and [Formula: see text]. The experimental constraints on the ZbLbL vertex form factor, [Formula: see text] play an important role in disfavoring the region of large mt(mt~200GeV) and large mH(mH~1000 GeV). If mt is precisely known, the present electroweak data give a rather strict upper bound on the Higgs mass, mH<140(300) GeV at 95% CL, for mt=160(175) GeV and for the above αs(mz) and [Formula: see text].

scholarly journals Off-diagonal Yukawa couplings in the s -channel charged Higgs production at LHC

2015 ◽  
Vol 741 ◽  
pp. 145-149 ◽  
Author(s):  
Majid Hashemi ◽  
Seyyed Mohammad Zebarjad ◽  
Hossein Bakhshalizadeh
Keyword(s):  
Higgs Production ◽  
Yukawa Couplings ◽  
Charged Higgs

scholarly journals Unitarity and anomalous top-quark Yukawa couplings

1995 ◽  
Vol 52 (5) ◽  
pp. 3115-3118 ◽  
Author(s):  
K. Whisnant ◽  
Bing-Lin Young ◽  
X. Zhang
Keyword(s):  
Top Quark ◽  
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.

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