scholarly journals High scale perturbative gauge coupling in R-parity conserving SUSY SO(10) with longer proton lifetime

2005 ◽  
Vol 44 (3) ◽  
pp. 447-457 ◽  
Author(s):  
M. K. Parida ◽  
B. D. Cajee
2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Maria Mehmood ◽  
Mansoor Ur Rehman ◽  
Qaisar Shafi

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).


2020 ◽  
Vol 80 (11) ◽  
Author(s):  
Tommy Ohlsson ◽  
Marcus Pernow ◽  
Erik Sönnerlind

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.


2005 ◽  
Vol 726 (1-2) ◽  
pp. 149-170 ◽  
Author(s):  
V. Barger ◽  
Jing Jiang ◽  
Paul Langacker ◽  
Tianjun Li

2021 ◽  
Vol 81 (12) ◽  
Author(s):  
John Ellis ◽  
Jason L. Evans ◽  
Natsumi Nagata ◽  
Dimitri V. Nanopoulos ◽  
Keith A. Olive

AbstractWe consider proton decay and $$g_\mu - 2$$ g μ - 2 in flipped SU(5) GUT models. We first study scenarios in which the soft supersymmetry-breaking parameters are constrained to be universal at some high scale $$M_{in}$$ M in above the standard GUT scale where the QCD and electroweak SU(2) couplings unify. In this case the proton lifetime is typically $$ > rsim 10^{36}$$ ≳ 10 36  years, too long to be detected in the foreseeable future, and the supersymmetric contribution to $$g_\mu - 2$$ g μ - 2 is too small to contribute significantly to resolving the discrepancy between the experimental measurement and data-driven calculations within the Standard Model. However, we identify a region of the constrained flipped SU(5) parameter space with large couplings between the 10- and 5-dimensional GUT Higgs representations where $$p \rightarrow e^+ \pi ^0$$ p → e + π 0 decay may be detectable in the Hyper-Kamiokande experiment now under construction, though the contribution to $$g_\mu -2$$ g μ - 2 is still small. A substantial contribution to $$g_\mu - 2$$ g μ - 2 is possible, however, if the universality constraints on the soft supersymmetry-breaking masses are relaxed. We find a ‘quadrifecta’ region where observable proton decay co-exists with a (partial) supersymmetric resolution of the $$g_\mu - 2$$ g μ - 2 discrepancy and acceptable values of $$m_h$$ m h and the relic LSP density.


2010 ◽  
Vol 25 (31) ◽  
pp. 5647-5665
Author(s):  
PRAN NATH

The existing data appear to provide hints of an underlying high scale theory. These arise from the gauge coupling unification, from the smallness of the neutrino masses, and via a nonvanishing muon anomaly. An overview of high scale models is given with a view to possible tests at the Large Hadron Collider. Specifically we discuss here some generic approaches to deciphering their signatures. We also consider an out of the box possibility of a four-generation model where the fourth generation is a mirror generation rather than a sequential generation. Such a scenario can lead to some remarkably distinct signatures at the LHC.


2008 ◽  
Vol 793 (1-2) ◽  
pp. 307-325 ◽  
Author(s):  
V. Barger ◽  
N.G. Deshpande ◽  
Jing Jiang ◽  
Paul Langacker ◽  
Tianjun Li

Author(s):  
Davide Meloni ◽  
Tommy Ohlsson ◽  
Marcus Pernow

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.


2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Paul Frederik Depta ◽  
Andreas Halsch ◽  
Janine Hütig ◽  
Sebastian Mendizabal ◽  
Owe Philipsen

Abstract Thermal leptogenesis, in the framework of the standard model with three additional heavy Majorana neutrinos, provides an attractive scenario to explain the observed baryon asymmetry in the universe. It is based on the out-of-equilibrium decay of Majorana neutrinos in a thermal bath of standard model particles, which in a fully quantum field theoretical formalism is obtained by solving Kadanoff-Baym equations. So far, the leading two-loop contributions from leptons and Higgs particles are included, but not yet gauge corrections. These enter at three-loop level but, in certain kinematical regimes, require a resummation to infinite loop order for a result to leading order in the gauge coupling. In this work, we apply such a resummation to the calculation of the lepton number density. The full result for the simplest “vanilla leptogenesis” scenario is by $$ \mathcal{O} $$ O (1) increased compared to that of quantum Boltzmann equations, and for the first time permits an estimate of all theoretical uncertainties. This step completes the quantum theory of leptogenesis and forms the basis for quantitative evaluations, as well as extensions to other scenarios.


2021 ◽  
Vol 111 (3) ◽  
Author(s):  
Giulio Bonelli ◽  
Francesco Fucito ◽  
Jose Francisco Morales ◽  
Massimiliano Ronzani ◽  
Ekaterina Sysoeva ◽  
...  

AbstractWe compute the $$\mathcal{N}=2$$ N = 2 supersymmetric partition function of a gauge theory on a four-dimensional compact toric manifold via equivariant localization. The result is given by a piecewise constant function of the Kähler form with jumps along the walls where the gauge symmetry gets enhanced. The partition function on such manifolds is written as a sum over the residues of a product of partition functions on $$\mathbb {C}^2$$ C 2 . The evaluation of these residues is greatly simplified by using an “abstruse duality” that relates the residues at the poles of the one-loop and instanton parts of the $$\mathbb {C}^2$$ C 2 partition function. As particular cases, our formulae compute the SU(2) and SU(3) equivariant Donaldson invariants of $$\mathbb {P}^2$$ P 2 and $$\mathbb {F}_n$$ F n and in the non-equivariant limit reproduce the results obtained via wall-crossing and blow up methods in the SU(2) case. Finally, we show that the U(1) self-dual connections induce an anomalous dependence on the gauge coupling, which turns out to satisfy a $$\mathcal {N}=2$$ N = 2 analog of the $$\mathcal {N}=4$$ N = 4 holomorphic anomaly equations.


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