scholarly journals Perturbative unification of gauge couplings in supersymmetric E6 models

2016 ◽  
Vol 31 (22) ◽  
pp. 1650130 ◽  
Author(s):  
Gi-Chol Cho ◽  
Nobuhito Maru ◽  
Kaho Yotsutani
Keyword(s):  
Renormalization Group ◽  
Gauge Coupling ◽  
Gauge Fields ◽  
Grand Unified Theories ◽  
Renormalization Group Equations ◽  
Unified Theories ◽  
Perturbative Regime ◽  
Gut Scale ◽  
Gauge Couplings ◽  
Matter Fields

We study gauge coupling unification in supersymmetric (SUSY) E6 models where an additional U(1)[Formula: see text] gauge symmetry is broken near the TeV scale and a number of exotic matter fields from the 27 representations have O(TeV) mass. Solving the two-loop renormalization group equations (RGE) of gauge couplings and a kinetic mixing coupling between the U(1)[Formula: see text] and U(1)Y gauge fields, we find that the gauge couplings fall into the non-perturbative regime below the grand unified theories (GUT) scale. We examine threshold corrections on the running of gauge couplings from both light and heavy ([Formula: see text] GUT scale) particles and show constraints on the size of corrections to achieve the perturbative unification of gauge couplings.

scholarly journals THE CURRENT PROBLEMS OF THE MINIMAL SO(10) GUT AND THEIR SOLUTIONS

2007 ◽  
Vol 16 (05) ◽  
pp. 1489-1503 ◽  
Author(s):  
TAKESHI FUKUYAMA ◽  
TATSURU KIKUCHI ◽  
NOBUCHIKA OKADA
Keyword(s):  
Predictive Power ◽  
Blow Up ◽  
Gauge Coupling ◽  
Neutrinoless Double Beta Decay ◽  
Double Beta Decay ◽  
Grand Unification ◽  
Warped Extra Dimension ◽  
Gut Scale ◽  
Gauge Couplings ◽  
Yukawa Sector

This talk consists of two parts. In part I we review how the minimal renormalizable supersymmetric SO (10) model, an SO (10) framework with only one 10 and one [Formula: see text] Higgs multiplets in the Yukawa sector, is attractive because of its highly predictive power. Indeed it not only gives a consistent predictions on neutrino oscillation data but also gives reasonable and interesting values for leptogenesis, LFV, muon g - 2, neutrinoless double beta decay etc. However, this model suffers from problems related to running of gauge couplings. The gauge coupling unification may be spoiled due to the presence of Higgs multiplets much lighter than the grand unification (GUT) scale. In addition, the gauge couplings blow up around the GUT scale because of the presence of Higgs multiplets of large representations. In part II we consider the minimal SO (10) model in the warped extra dimension and show a possibility to solve these problems.

scholarly journals GRAND UNIFICATION WITHOUT HIGGS BOSONS

2012 ◽  
Vol 13 ◽  
pp. 20-27
Author(s):  
STEPHEN M. BARR ◽  
XAVIER CALMET
Keyword(s):  
Fixed Point ◽  
Weak Interactions ◽  
W Bosons ◽  
Gauge Coupling ◽  
Baryon Number ◽  
Higgs Bosons ◽  
Unified Theory ◽  
Grand Unified Theory ◽  
Grand Unified Theories ◽  
Unified Theories

We discuss how a model for the electroweak interactions without a Higgs could be embedded into a grand unified theory. The requirement of a non-trivial fixed point in the SU(2) sector of the weak interactions together with the requirement of the numerical unification of the gauge couplings leads to a prediction for the value of the SU(2) gauge coupling in the fixed point regime. The fixed point regime must be in the TeV region to solve the unitarity problem in the elastic scattering of W bosons. We find that the unification scale is at about 1014 GeV. Viable grand unified theories must thus conserve baryon number. We discuss how to build such a model without using Higgs bosons.

scholarly journals 2D QUANTUM GRAVITY COUPLED TO RENORMALIZABLE MATTER FIELDS

1994 ◽  
Vol 09 (32) ◽  
pp. 5689-5709 ◽  
Author(s):  
JAN AMBJØRN ◽  
KAZUO GHOROKU
Keyword(s):  
Renormalization Group ◽  
Quantum Gravity ◽  
Effective Action ◽  
Two Dimensional ◽  
Conformally Invariant ◽  
Renormalization Group Equations ◽  
Β Function ◽  
Matter Fields

We consider two-dimensional quantum gravity coupled to matter fields which are renormalizable but not conformally invariant. Questions concerning the β function and the effective action are addressed, and the effective action and the dressed renormalization group equations are determined for various matter potentials.

scholarly journals COMPLETE CLASSES OF GUTS WITH VANISHING ONE-LOOP BETA FUNCTIONS

1994 ◽  
Vol 09 (29) ◽  
pp. 5053-5075
Author(s):  
WOLFGANG LUCHA ◽  
FRANZ F. SCHÖBERL
Keyword(s):  
Gauge Coupling ◽  
Coupling Constants ◽  
Coupling Constant ◽  
Finiteness Conditions ◽  
Grand Unified Theories ◽  
Unified Theories ◽  
Dimensionless Coupling ◽  
The One ◽  
The Masses ◽  
Gauge Coupling Constant

By explicit solution of the one-loop finiteness conditions for all dimensionless coupling constants (i.e. the gauge coupling constant as well as Yukawa and quartic scalar-boson self-interaction coupling constants), two classes of grand unified theories characterized by renormalization-group beta functions which all vanish at least at the one-loop level are constructed and analyzed with respect to the (suspected) appearance of quadratic divergences, with the result that without exception in all of these models the masses of both vector and scalar bosons receive quadratically divergent one-loop contributions.

scholarly journals Cosmological evolution of fundamental constants: From theory to experiment

2015 ◽  
Vol 30 (22) ◽  
pp. 1540028 ◽  
Author(s):  
Xavier Calmet ◽  
Matthias Keller
Keyword(s):  
Time Evolution ◽  
Gauge Coupling ◽  
Current Status ◽  
Experimental Point ◽  
Fundamental Constants ◽  
Cosmological Time ◽  
Proton Mass ◽  
Grand Unified Theories ◽  
Unified Theories ◽  
Theoretical Side

In this paper, we discuss a possible cosmological time evolution of fundamental constants from the theoretical and experimental point of views. On the theoretical side, we explain that such a cosmological time evolution is actually something very natural which can be described by mechanisms similar to those used to explain cosmic inflation. We then discuss implications for grand unified theories, showing that the unification condition of the gauge coupling could evolve with cosmological time. Measurements of the electron-to-proton mass ratio can test grand unified theories using low energy data. Following the theoretical discussion, we review the current status of precision measurements of fundamental constants and their potential cosmological time dependence.

scholarly journals Employing nucleon decay as a fingerprint of SUSY GUT models using SusyTCProton

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Stefan Antusch ◽  
Christian Hohl ◽  
Vasja Susič
Keyword(s):  
Software Tool ◽  
Decay Rates ◽  
Low Energy ◽  
Nucleon Decay ◽  
Mixing Parameters ◽  
Grand Unified Theories ◽  
Fermion Masses ◽  
Unified Theories ◽  
Rich Information ◽  
Gut Scale

Abstract While the observation of nucleon decay would be a smoking gun of Grand Unified Theories (GUTs) in general, the ratios between the decay rates of the various channels carry rich information about the specific GUT model realization. To investigate this fingerprint of GUT models in the context of supersymmetric (SUSY) GUTs, we present the software tool SusyTCProton, which is an extension of the module SusyTC to be used with the REAP package. It allows to calculate nucleon decay rates from the relevant dimension five GUT operators specified at the GUT scale, including the full loop-dressing at the SUSY scale. As an application, we investigate the fingerprints of two example GUT toy models with different flavor structures, performing an MCMC analysis to include the experimental uncertainties for the charged fermion masses and CKM mixing parameters. While both toy models provide equally good fits to the low energy data, we show how they could be distinguished via their predictions of ratios for nucleon decay rates. Together with SusyTCProton we also make the additional module ProtonDecay public. It can be used independently from REAP and allows to calculate nucleon decay rates from given D = 5 and D = 6 operator coefficients (accepting the required SUSY input for the D = 5 case in SLHA format). The D = 6 functionality can also be used to calculate nucleon decay in non-SUSY GUTs.

scholarly journals Confronting SO(10) GUTs with proton decay and gravitational waves

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Stephen F. King ◽  
Silvia Pascoli ◽  
Ye-Ling Zhou ◽  
Jessica Turner
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Cosmic String ◽  
Cosmic Strings ◽  
Proton Decay ◽  
Null Results ◽  
Grand Unified Theories ◽  
Unified Theories ◽  
Proton Lifetime ◽  
Gut Scale

Abstract Grand Unified Theories (GUT) predict proton decay as well as the formation of cosmic strings which can generate gravitational waves. We determine which non-supersymmetric SO(10) breaking chains provide gauge unification in addition to a gravitational signal from cosmic strings. We calculate the GUT and intermediate scales for these SO(10) breaking chains by solving the renormalisation group equations at the two-loop level. This analysis predicts the GUT scale, hence the proton lifetime, in addition to the scale of cosmic string generation and thus the associated gravitational wave signal. We determine which SO(10) breaking chains survive in the event of the null results of the next generation of gravitational waves and proton decay searches and determine the correlations between proton decay and gravitational waves scales if these observables are measured.

scholarly journals A PARTICULAR CLASS OF GUTS WITH VANISHING ONE-LOOP BETA FUNCTIONS

1994 ◽  
Vol 09 (32) ◽  
pp. 5791-5800
Author(s):  
WOLFGANG LUCHA ◽  
FRANZ F. SCHÖBERL
Keyword(s):  
Renormalization Group ◽  
Explicit Solution ◽  
Coupling Constants ◽  
Scalar Boson ◽  
Finiteness Conditions ◽  
Yukawa Couplings ◽  
Grand Unified Theories ◽  
Unified Theories ◽  
The One

By explicit solution of the one-loop finiteness conditions for gauge and quartic scalar-boson self-interaction coupling constants, a particular class of grand unified theories with vanishing Yukawa couplings as well as vanishing one-loop renormalization-group beta functions is constructed.

scholarly journals SPARTICLE MASS SPECTRUM IN GRAND UNIFIED THEORIES

2007 ◽  
Vol 22 (19) ◽  
pp. 3229-3259 ◽  
Author(s):  
B. ANANTHANARAYAN ◽  
P. N. PANDITA
Keyword(s):  
Mass Spectrum ◽  
Gauge Group ◽  
Gauge Groups ◽  
Grand Unified Theories ◽  
Renormalization Group Equations ◽  
The Standard Model ◽  
Unified Theories ◽  
The One ◽  
The Impact ◽  
Standard Model Gauge Group

We carry out a detailed analysis of sparticle mass spectrum in supersymmetric grand unified theories. We consider the spectroscopy of the squarks and sleptons in SU (5) and SO (10) grand unified theories, and show how the underlying supersymmetry breaking parameters of these theories can be determined from a measurement of different sparticle masses. This analysis is done analytically by integrating the one-loop renormalization group equations with appropriate boundary conditions implied by the underlying grand unified gauge group. We also consider the impact of nonuniversal gaugino masses on the sparticle spectrum, especially the neutralino and chargino masses which arise in supersymmetric grand unified theories with nonminimal gauge kinetic function. In particular, we study the interrelationships between the squark and slepton masses which arise in grand unified theories at the one-loop level, which can be used to distinguish between the different underlying gauge groups and their breaking pattern to the Standard Model gauge group. We also comment on the corrections that can affect these one-loop results.

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