UPPER LIMITS ON THE TOP QUARK MASS IN MODELS WITH NEW GAUGE BOSONS

1990 ◽  
Vol 05 (02) ◽  
pp. 115-123 ◽  
Author(s):  
THOMAS G. RIZZO
Keyword(s):  
Top Quark ◽  
Quark Mass ◽  
Top Quark Mass ◽  
Gauge Bosons ◽  
Gauge Sector ◽  
Upper Limit ◽  
Upper Limits ◽  
The Standard Model ◽  
Lower Limits ◽  
Rule Out

The experimental value of the ρ parameter is used to obtain an upper limit on the top-quark mass (mt) in models with extended gauge sectors. This limit is found to be generally stronger than that obtained from similar considerations in the Standard Model (SM). This bound, however, is shown to depend strongly on the particular extension of the usual SM gauge sector under consideration. Improved experimental lower limits on mt can also be used to rule out large regions of the parameter space of extended electroweak models.

NARROW-RESONANCE IN e−e− SCATTERING DUE TO ADDITIONAL GAUGE BOSON

1996 ◽  
Vol 11 (09) ◽  
pp. 1621-1625 ◽  
Author(s):  
PAUL H. FRAMPTON
Keyword(s):  
Standard Model ◽  
Top Quark ◽  
Quark Mass ◽  
Special Role ◽  
Top Quark Mass ◽  
Narrow Resonance ◽  
Gauge Bosons ◽  
The Third ◽  
High Energies ◽  
The Standard Model

It now appears phenomenologically that the third family may be essentially different from the first two. Particularly the high value of the top quark mass suggests a special role. In the standard model all three families are treated similarly [becoming exactly the same at asymptotically high energies] so I need to extend the model to accommodate the goal of a really different third family. In this article I describe one such viable extension, the 331 model which predicts bileptonic gauge bosons.

scholarly journals HIGGS PARTICLES AT FUTURE HADRON AND ELECTRON-POSITRON COLLIDERS

1995 ◽  
Vol 10 (01) ◽  
pp. 1-63 ◽  
Author(s):  
A. DJOUADI
Keyword(s):  
Top Quark ◽  
Quark Mass ◽  
High Energy ◽  
High Energy Electron ◽  
Hadron Colliders ◽  
Top Quark Mass ◽  
Supersymmetric Extension ◽  
Fundamental Properties ◽  
Electron Positron ◽  
The Standard Model

The prospects for discovering Higgs particles and studying their fundamental properties at future high-energy electron-positron and hadron colliders are reviewed. Both the Standard Model Higgs boson and the Higgs particles of its minimal supersymmetric extension are discussed. We update various results by taking into account the new value of the top-quark mass obtained by the CDF Collaboration, and by including radiative corrections, some of which have been calculated only recently.

scholarly journals THE LIMITS OF CUSTODIAL SYMMETRY

2010 ◽  
Vol 25 (27n28) ◽  
pp. 5082-5096
Author(s):  
R. SEKHAR CHIVUKULA ◽  
ROSHAN FOADI ◽  
ELIZABETH H. SIMMONS ◽  
STEFANO DI CHIARA
Keyword(s):  
Standard Model ◽  
Top Quark ◽  
Quark Mass ◽  
Electroweak Symmetry ◽  
Top Quark Mass ◽  
Particle Content ◽  
Dirac Mass ◽  
The Standard Model ◽  
Custodial Symmetry ◽  
Weak Doublet

We introduce a toy model implementing the proposal of using a custodial symmetry to protect the [Formula: see text] coupling from large corrections. This "doublet-extended standard model" adds a weak doublet of fermions (including a heavy partner of the top quark) to the particle content of the standard model in order to implement an O(4) × U(1)X ~ SU(2)L × SU(2)R × PLR × U(1)X symmetry in the top-quark mass generating sector. This symmetry is softly broken to the gauged SU(2)L × U(1)Y electroweak symmetry by a Dirac mass M for the new doublet; adjusting the value of M allows us to explore the range of possibilities between the O(4)-symmetric (M → 0) and standard-model-like (M → ∞) limits.

TOP QUARK MASS IN THE CONDENSATE MODEL AND THE POSSIBILITY OF COLORED BOSONS

1993 ◽  
Vol 08 (26) ◽  
pp. 2465-2470 ◽  
Author(s):  
ANIRBAN KUNDU ◽  
TRIPTESH DE ◽  
BINAYAK DUTTA-ROY
Keyword(s):  
Top Quark ◽  
Quark Mass ◽  
Quark Condensate ◽  
Electroweak Symmetry Breaking ◽  
Electroweak Symmetry ◽  
Top Quark Mass ◽  
Group Approach ◽  
Composite Bosons ◽  
The Standard Model ◽  
Renormalization Group Approach

The dynamical electroweak symmetry breaking of the Standard Model triggered by a top quark condensate (induced by an effective strong interaction, associated with a highenergy scale, of the form [Formula: see text]) usually requires an embarrassingly large top quark mass. A suggestion that this problem could be avoided through the introduction of an additional interaction [Formula: see text] (where [Formula: see text] are SU(3)c generators á la Okubo) is analyzed using the renormalization group approach. The mass of the top quark and the concomitant emergence of colored composite bosons is discussed.

scholarly journals SUPERSYMMETRY AND UNIFICATION: HEAVY TOP WAS THE KEY

2012 ◽  
Vol 13 ◽  
pp. 182-190 ◽  
Author(s):  
GORAN SENJANOVIĆ
Keyword(s):  
Top Quark ◽  
Quark Mass ◽  
Correct Prediction ◽  
Top Quark Mass ◽  
Weak Mixing Angle ◽  
Mixing Angle ◽  
Grand Unified Theories ◽  
The Standard Model ◽  
Unified Theories ◽  
History Of

I review the history of the unification of gauge couplings of the Standard Model. I start by recalling the history of the most important prediction of low-energy supersymmetry: the correct prediction of the weak mixing angle tied to the prediction of a large top quark mass. I then turn to the discussion of the present day situation of the minimal supersymmetric Grand Unified Theories based on SU(5) and SO(10) groups. For the sake of completeness I also summarize the problems and possible solution of the minimal ordinary SU(5).

PREDICTION OF THE TOP QUARK MASS IN A FINITE ELECTROWEAK THEORY

1991 ◽  
Vol 06 (29) ◽  
pp. 2697-2703
Author(s):  
M. CLAYTON ◽  
J. W. MOFFAT
Keyword(s):  
Top Quark ◽  
Quark Mass ◽  
Vacuum Polarization ◽  
Local Scale ◽  
Higgs Mechanism ◽  
Electroweak Theory ◽  
Particle Spectrum ◽  
Top Quark Mass ◽  
Gauge Bosons ◽  
Non Local

A parameter-free prediction of the top quark mass is obtained from the calculation of [Formula: see text] in a finite non-local electroweak theory, in which the W and Z gauge bosons acquire their masses through the lowest order vacuum polarization graphs containing fermion loops. The SU (2)× U (1) gauge symmetry is broken to U (1) em by a symmetry breaking measure factor in the path integral without resorting to a Higgs mechanism. Using the ratio of the W and Z masses obtained from the average of the UAI, UA2 and the CDF experiments, we predict mt=86±33 GeV and the gauge boson non-local scale Λw=523±4 GeV . Using the CDF measured W mass, we find mt=125±40 GeV and Λw=529±6 GeV . The particle spectrum in the model contains the W, Z and photon gauge bosons and the standard three generations of leptons and quarks, including the anticipated top quark.

scholarly journals Towards a Higgs mass determination in asymptotically safe gravity with a dark portal

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Astrid Eichhorn ◽  
Martin Pauly ◽  
Shouryya Ray
Keyword(s):  
Standard Model ◽  
Top Quark ◽  
Quark Mass ◽  
Higgs Mass ◽  
Beyond The Standard Model ◽  
Top Quark Mass ◽  
Dark Sector ◽  
Central Value ◽  
The Standard Model ◽  
Higgs Portal

Abstract There are indications that an asymptotically safe UV completion of the Standard Model with gravity could constrain the Higgs self-coupling, resulting in a prediction of the Higgs mass close to the vacuum stability bound in the Standard Model. The predicted value depends on the top quark mass and comes out somewhat higher than the experimental value if the current central value for the top quark mass is assumed. Beyond the Standard Model, the predicted value also depends on dark fields coupled through a Higgs portal. Here we study the Higgs self-coupling in a toy model of the Standard Model with quantum gravity that we extend by a dark scalar and fermion. Within the approximations used in [1], there is a single free parameter in the asymptotically safe dark sector, as a function of which the predicted (toy model) Higgs mass can be lowered due to mixing effects if the dark sector undergoes spontaneous symmetry breaking.

scholarly journals LIMIT ON THE COLOR-TRIPLET HIGGS MASS IN THE MINIMUM SUPERSYMMETRIC SU(5) MODEL

1995 ◽  
Vol 10 (30) ◽  
pp. 2267-2278 ◽  
Author(s):  
J. HISANO ◽  
T. MOROI ◽  
K. TOBE ◽  
T. YANAGIDA
Keyword(s):  
Renormalization Group ◽  
Lower Limit ◽  
Top Quark ◽  
Quark Mass ◽  
Higgs Mass ◽  
Group Analysis ◽  
Proton Decay ◽  
Top Quark Mass ◽  
Renormalization Group Analysis ◽  
Upper Limit

In the minimum supersymmetric SU(5) GUT, we derive the upper limit on the mass of the color-triplet Higgs multiplets as [Formula: see text] (90% C.L.) taking all possible corrections into account in a renormalization group analysis. If the above upper limit is compared with a lower limit on [Formula: see text] from the negative search for the proton decay; [Formula: see text] (in which effects of the larger top-quark mass are included), the minimum supersymmetric SU(5) GUT is severely constrained.

THE STANDARD MODEL WITH THREE GENERATIONS: CLOSING IN ON THE TOP QUARK MASS

1989 ◽  
Vol 04 (04) ◽  
pp. 753-768 ◽  
Author(s):  
F. HALZEN ◽  
C. S. KIM ◽  
S. PAKVASA
Keyword(s):  
Experimental Data ◽  
Standard Model ◽  
Top Quark ◽  
Quark Mass ◽  
New Physics ◽  
Experimental Information ◽  
Beyond The Standard Model ◽  
Top Quark Mass ◽  
Three Generations ◽  
The Standard Model

Within the standard model with three generations we fit the top quark mass mt by combining experimental information of [Formula: see text] and [Formula: see text] mixing, CP-violation in K decay and the ratio Γ(W)/Γ(Z) extracted from [Formula: see text] collider data. We conclude that [Formula: see text] where the "systematic error" associated with theoretical ambiguities in performing the calculations is likely to be significantly larger than the quoted 10 GeV error associated with input parameters and experimental data. The anticipated value essentially guarantees the discovery of the top quark by existing experiments. Failure to discover it should force us to reconsider generally accepted calculational procedures before it signals new physics beyond the standard model. We discuss this in some detail.

scholarly journals Search for Single Top Production with CDF

2001 ◽  
Vol 16 (supp01a) ◽  
pp. 382-385 ◽  
Author(s):  
◽  
T. Kikuchi ◽  
S. K. Wolinski ◽  
L. Demortier ◽  
S. Kim ◽  
...  
Keyword(s):  
Cross Section ◽  
Top Quark ◽  
Standard Model Prediction ◽  
Gluon Fusion ◽  
Upper Limit ◽  
Single Top ◽  
Upper Limits ◽  
The Standard Model ◽  
Top Quark Production ◽  
Quark Production

We search for Standrod Model single-top-quark production in the W -gluon fusion and W* channels using 106 pb-1 of data from [Formula: see text] collisions at [Formula: see text] collected with the Collider Detector at Fermilab. We set an upper limit at 95% C.L. on the combined Wg + W* single-top cross section of 13.5 pb, roughly five-and-a-half times larger larer than the standard model prediction. Separate 95% C.L. upper limits in the Wg-fusion and W* channels ae also determined and are found to be 13.5 and 12.9 pb respectively.

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