scholarly journals Realizing unification in two different SO(10) models with one intermediate breaking scale

2020 ◽  
Vol 80 (11) ◽  
Author(s):  
Tommy Ohlsson ◽  
Marcus Pernow ◽  
Erik Sönnerlind
Keyword(s):  
Gauge Coupling ◽  
Scalar Fields ◽  
Matching Conditions ◽  
Proton Lifetime ◽  
The Masses ◽  
Breaking Scale

AbstractWe derive the threshold corrections in $$\text {SO}(10)$$ SO ( 10 ) grand unified models with the intermediate symmetry being flipped $$\,\text {SU}(5)\times \text {U}(1)$$ SU ( 5 ) × U ( 1 ) or $$\,\text {SU}(3)\times \,\text {SU}(2)\times \text {U}(1)\times \text {U}(1)$$ SU ( 3 ) × SU ( 2 ) × U ( 1 ) × U ( 1 ) , with the masses of the scalar fields set by the survival hypothesis. These models do not achieve gauge coupling unification if the matching conditions do not take threshold corrections into account. We present results showing the required size of threshold corrections for any value of the intermediate and unification scales. In particular, our results demonstrate that both of these models are disfavored since they require large threshold corrections to allow for unification with a predicted proton lifetime above current experimental bounds.

scholarly journals Gravitational waves from fundamental axion dynamics

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Anish Ghoshal ◽  
Alberto Salvio
Keyword(s):  
Phase Transition ◽  
Symmetry Breaking ◽  
Gravitational Waves ◽  
Wave Spectrum ◽  
Gauge Coupling ◽  
Energy Limit ◽  
The Masses ◽  
Infinite Energy ◽  
Independent Parameters ◽  
Breaking Scale

Abstract A totally asymptotically free QCD axion model, where all couplings flow to zero in the infinite energy limit, was recently formulated. A very interesting feature of this fundamental theory is the ability to predict some low-energy observables, like the masses of the extra fermions and scalars. Here we find and investigate a region of the parameter space where the Peccei-Quinn (PQ) symmetry is broken quantum mechanically through the Coleman-Weinberg mechanism. This results in an even more predictive framework: the axion sector features only two independent parameters (the PQ symmetry breaking scale and the QCD gauge coupling). In particular, we show that the PQ phase transition is strongly first order and can produce gravitational waves within the reach of future detectors. The predictivity of the model leads to a rigid dependence of the phase transition (like its duration and the nucleation temperature) and the gravitational wave spectrum on the PQ symmetry breaking scale and the QCD gauge coupling.

scholarly journals Threshold effects in SO(10) models with one intermediate breaking scale

2020 ◽  
Vol 80 (9) ◽  
Author(s):  
Davide Meloni ◽  
Tommy Ohlsson ◽  
Marcus Pernow
Keyword(s):  
Standard Model ◽  
Symmetry Breaking ◽  
Particle Physics ◽  
Gauge Coupling ◽  
Grand Unification ◽  
Threshold Effects ◽  
The Standard Model ◽  
Proton Lifetime ◽  
Supersymmetric Theories ◽  
Breaking Scale

AbstractDespite the successes of the Standard Model of particle physics, it is known to suffer from a number of deficiencies. Several of these can be addressed within non-supersymmetric theories of grand unification based on $$\text {SO}(10)$$ SO ( 10 ) . However, achieving gauge coupling unification in such theories is known to require additional physics below the unification scale, such as symmetry breaking in multiple steps. Many such models are disfavored due to bounds on the proton lifetime. Corrections arising from threshold effects can, however, modify these conclusions. We analyze all seven relevant breaking chains with one intermediate symmetry breaking scale, assuming the “survival hypothesis” for the scalar masses. Two are allowed by proton lifetime and two are disfavored by a failure to unify the gauge couplings. The remaining three unify at a too low scale, but can be salvaged by various amounts of threshold corrections. We parametrize this and thereby rank the models by the size of the threshold corrections required to save them.

scholarly journals Effective Scalar Potential in Asymptotically Safe Quantum Gravity

Universe ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 45
Author(s):  
Christof Wetterich
Keyword(s):  
Quantum Gravity ◽  
Top Quark ◽  
Particle Physics ◽  
Scalar Potential ◽  
Scalar Fields ◽  
The Standard Model ◽  
Scaling Potential ◽  
Realistic Description ◽  
The Masses ◽  
Dynamical Dark Energy

We compute the effective potential for scalar fields in asymptotically safe quantum gravity. A scaling potential and other scaling functions generalize the fixed point values of renormalizable couplings. The scaling potential takes a non-polynomial form, approaching typically a constant for large values of scalar fields. Spontaneous symmetry breaking may be induced by non-vanishing gauge couplings. We strengthen the arguments for a prediction of the ratio between the masses of the top quark and the Higgs boson. Higgs inflation in the standard model is unlikely to be compatible with asymptotic safety. Scaling solutions with vanishing relevant parameters can be sufficient for a realistic description of particle physics and cosmology, leading to an asymptotically vanishing “cosmological constant” or dynamical dark energy.

scholarly journals Observable proton decay in flipped SU(5)

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Maria Mehmood ◽  
Mansoor Ur Rehman ◽  
Qaisar Shafi
Keyword(s):  
Neutrino Mass ◽  
Gauge Coupling ◽  
Proton Decay ◽  
Type I ◽  
Mass Model ◽  
Intermediate Scale ◽  
Decay Channels ◽  
Proton Lifetime ◽  
Hybrid Inflation ◽  
Neutrino Mass Models

Abstract We explore proton decay in a class of realistic supersymmetric flipped SU(5) models supplemented by a U(1)R symmetry which plays an essential role in implementing hybrid inflation. Two distinct neutrino mass models, based on inverse seesaw and type I seesaw, are identified, with the latter arising from the breaking of U(1)R by nonrenormalizable superpotential terms. Depending on the neutrino mass model an appropriate set of intermediate scale color triplets from the Higgs superfields play a key role in proton decay channels that include p → (e+, μ+) π0, p → (e+, μ+) K0, p →$$ \overline{v}{\pi}^{+} $$ v ¯ π + , and p →$$ \overline{v}{K}^{+} $$ v ¯ K + . We identify regions of the parameter space that yield proton lifetime estimates which are testable at Hyper-Kamiokande and other next generation experiments. We discuss how gauge coupling unification in the presence of intermediate scale particles is realized, and a Z4 symmetry is utilized to show how such intermediate scales can arise in flipped SU(5). Finally, we compare our predictions for proton decay with previous work based on SU(5) and flipped SU(5).

BARYOGENESIS IN AN SO(10) GUT MODEL WITH PATI–SALAM INTERMEDIATE SYMMETRY

1998 ◽  
Vol 13 (19) ◽  
pp. 1539-1546
Author(s):  
F. BUCCELLA ◽  
O. PISANTI ◽  
L. ROSA
Keyword(s):  
Experimental Data ◽  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Neutrino Oscillations ◽  
Baryon Asymmetry ◽  
Gauge Model ◽  
Electroweak Scale ◽  
Proton Lifetime ◽  
The Universe ◽  
Breaking Scale

The possibility of generating the observed baryon asymmetry of the universe in an SO(10) gauge model with spontaneous symmetry breaking pattern [Formula: see text] is studied. We find it possible to generate a [Formula: see text], converting the leptonic number produced at the B- L breaking scale via the B+L violating processes mediated by sphalerons at the electroweak scale. The resulting picture is tested against the limit coming from experimental data: proton lifetime and neutrino oscillations.

scholarly journals Higgs Portal Inflation with Fermionic Dark Matter

2018 ◽  
Vol 168 ◽  
pp. 06002
Author(s):  
Aditya Aravind ◽  
Minglei Xiao ◽  
Jiang-Hao Yu
Keyword(s):  
Dark Matter ◽  
Scalar Potential ◽  
Scalar Fields ◽  
Fermionic Field ◽  
Planck Data ◽  
Slow Roll ◽  
The Standard Model ◽  
The Masses ◽  
Higgs Portal

We discuss the inflationary model presented in [1], involving a gauge singlet scalar field and fermionic dark matter added to the standard model. Either the Higgs or the singlet scalar could play the role of the inflaton, and slow roll is realized through its non-minimal coupling to gravity. The effective scalar potential is stabilized by the mixing between the scalars as well as the coupling with the fermionic field. Mixing of the two scalars also provides a portal to dark matter. Constraints on the model come from perturbativity and stability, collider searches and dark matter constraints and impose a constraining relationship on the masses of dark matter and scalar fields. Inflationary predictions are generically consistent with current Planck data.

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 CURRENT ALGEBRA BASED EFFECTIVE CHIRAL THEORY OF MESONS AND A NEW EW THEORY

2006 ◽  
Vol 21 (04) ◽  
pp. 950-953
Author(s):  
Bing An Li
Keyword(s):  
Gauge Boson ◽  
Current Algebra ◽  
Axial Vector ◽  
Scalar Fields ◽  
Effective Theory ◽  
Vector Mesons ◽  
Chiral Theory ◽  
Gauge Fixing ◽  
The Masses ◽  
A Current

A current algebra based effective chiral theory of pseudoscalar, vector, axial-vector mesons is reviewed. A new mechanism generating the masses and guage fixing terms of gauge boson is revealed from this effective theory. A EW theory without Higgs is proposed. The masses and gauge fixing terms of W and Z are dynamically generated. Three heavy scalar fields are dynamically generated too. They are ghosts.

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