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).

scholarly journals Top-Quark Mass in Grand-Unified Theories with Intermediate Scales

1985 ◽  
Vol 55 (8) ◽  
pp. 787-790 ◽  
Author(s):  
C. Panagiotakopoulos ◽  
Q. Shafi ◽  
C. Wetterich
Keyword(s):  
Top Quark ◽  
Quark Mass ◽  
Top Quark Mass ◽  
Grand Unified Theories ◽  
Unified Theories

scholarly journals Top-quark-mass prediction from supersymmetric grand unified theories

1991 ◽  
Vol 44 (5) ◽  
pp. 1613-1615 ◽  
Author(s):  
B. Ananthanarayan ◽  
G. Lazarides ◽  
Q. Shafi
Keyword(s):  
Top Quark ◽  
Quark Mass ◽  
Top Quark Mass ◽  
Grand Unified Theories ◽  
Unified Theories

scholarly journals Mixed EW-QCD leading fermionic three-loop corrections at $$ \mathcal{O} $$(αsα2) to electroweak precision observables

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Lisong Chen ◽  
Ayres Freitas
Keyword(s):  
Top Quark ◽  
Z Boson ◽  
W Boson ◽  
Boson Mass ◽  
Top Quark Mass ◽  
Weak Mixing Angle ◽  
Mixing Angle ◽  
The Standard Model ◽  
Precision Observables ◽  
Electroweak Precision

Abstract Measurements of electroweak precision observables at future electron-position colliders, such as the CEPC, FCC-ee, and ILC, will be sensitive to physics at multi-TeV scales. To achieve this sensitivity, precise predictions for the Standard Model expectations of these observables are needed, including corrections at the three- and four-loop level. In this article, results are presented for the calculation of a subset of three-loop mixed electroweak-QCD corrections, stemming from diagrams with a gluon exchange and two closed fermion loops. The numerical impact of these corrections is illustrated for a number of applications: the prediction of the W-boson mass from the Fermi constant, the effective weak mixing angle, and the partial and total widths of the Z boson. Two alternative renormalization schemes for the top-quark mass are considered, on-shell and $$ \overline{\mathrm{MS}} $$ MS ¯ .

scholarly journals Determination of the Proton's Weak Charge and Its Constraints on the Standard Model

2019 ◽  
Vol 69 (1) ◽  
pp. 191-217 ◽  
Author(s):  
Roger D. Carlini ◽  
Willem T.H. van Oers ◽  
Mark L. Pitt ◽  
Gregory R. Smith
Keyword(s):  
Standard Model ◽  
Parity Violation ◽  
Valence Quark ◽  
Weak Mixing Angle ◽  
Weak Charge ◽  
Mixing Angle ◽  
The Standard Model ◽  
History Of ◽  
Bsm Physics

This article discusses some of the history of parity-violation experiments that culminated in the Qweak experiment, which provided the first determination of the proton's weak charge [Formula: see text]. The guiding principles necessary to the success of that experiment are outlined, followed by a brief description of the Qweak experiment. Several consistent methods used to determine [Formula: see text] from the asymmetry measured in the Qweak experiment are explained in detail. The weak mixing angle sin2θw determined from [Formula: see text] is compared with results from other experiments. A description of the procedure for using the [Formula: see text] result on the proton to set TeV-scale limits for new parity-violating semileptonic physics beyond the Standard Model (BSM) is presented. By also considering atomic parity-violation results on cesium, the article shows how this result can be generalized to set limits on BSM physics, which couples to any combination of valence quark flavors. Finally, the discovery space available to future weak-charge measurements is explored.

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 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.

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.

Finite unified theories and the top quark mass

1995 ◽  
Vol 37 (3) ◽  
pp. 98-105 ◽  
Author(s):  
Myriam Mondragón ◽  
George Zoupanos
Keyword(s):  
Top Quark ◽  
Quark Mass ◽  
Top Quark Mass ◽  
Unified Theories
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