Topological defects in the left-right symmetric model and their relevance to cosmology

Yajnik, Urjit A.; Widyan, Hatem; Choudhury, Debajyoti; Mahajan, Shivani; Mukherjee, Avijit

doi:10.1103/physrevd.59.103508

Cited by 11 publications

(13 citation statements)

References 43 publications

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“…Also, the 4th power dependence on M 1 of equation (29) and the rather narrow range of the observed value of η 0 given by equation (26) together imply that, in order for the SD process to explain the observed BAU, M 1 (and equivalently h 1 ) cannot be much smaller than their respective values saturating the above constraints.…”

Section: B Slow Death Casementioning

confidence: 91%

“…From (33) and (26) we see that, considering the most optimistic situation with f QD = 1, the QD process is relevant for BAU only for In general, using the constraint (17) on f QD in (33) we get…”

Section: Quick Death Casementioning

confidence: 99%

“…The formation of cosmic strings in the later phases is of great interest since these "light" (i.e., lighter than GUT scale) cosmic strings do not conflict with any cosmological observations. The Z 2 strings of the low energy theory was investigated in an earlier work [26].…”

Section: U (1) B−l Cosmic Strings and Neutrino Zero Modesmentioning

confidence: 99%

“…where we have defined the Yukawa coupling At the same time, for a given η B−L satisfying (30), in order that the contribution (29) not exceed the highest allowed observed value of η 0 given by equation (26), the Yukawa coupling h 1 must satisfy the constraint…”

Section: B Slow Death Casementioning

confidence: 99%

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B−Lcosmic strings and baryogenesis

2004

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Cosmic strings arising from breaking of the U (1) B−L gauge symmetry that occurs in a wide variety of unified models can carry zero modes of heavy Majorana neutrinos. Decaying and/or repeatedly self-interacting closed loops of these "B − L" cosmic strings can be a non-thermal source of heavy right-handed Majorana neutrinos whose decay can contribute to the observed baryon asymmetry of the Universe (BAU) via the leptogenesis route. The B − L cosmic strings are expected in GUT models such as SO (10)

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Section: B Slow Death Casementioning

confidence: 91%

Section: Quick Death Casementioning

confidence: 99%

Section: U (1) B−l Cosmic Strings and Neutrino Zero Modesmentioning

confidence: 99%

Section: B Slow Death Casementioning

confidence: 99%

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B−Lcosmic strings and baryogenesis

2004

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“…If the left-right symmetry were exact, the first stage of breaking gives rise to stable domain walls [33,34,35] interpolating between the L and R-like regions. By L-like we mean regions favored by the observed phenomenology, while in the R-like regions the vacuum expectation value of ∆ R is zero.…”

Section: Lepton Asymmetry In Left-right Symmetric Modelmentioning

confidence: 99%

GaugedB−Lsymmetry and baryogenesis via leptogenesis at TeV scale

Sahu

Yajnik

2005

Phys. Rev. D

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It is shown that the requirement of preservation of baryon asymmetry does not rule out a scale for leptogenesis as low as 10 TeV. The conclusions are compatible with see-saw mechanism if for example the pivot mass scale for neutrinos is ≈ 10 −2 that of the charged leptons. We explore the parameter spacem 1 -M 1 of relevant light and heavy neutrino masses by solving Boltzmann equations. A viable scenario for obtaining baryogenesis in this way is presented in the context of gauged B − L symmetry.

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Stability Longevity and All That: False Vacua and Topological Defects

Yajnik

2017

Gravity and the Quantum

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I present two interesting studies related to the role of solitons in theories with spontaneous symmetry breaking. Quantised fermions coupled to solitons are known to induce fractional fermion number. I present an example where an unstable topological solution binding a zero mode of a majorana fermion gets stabilised due to the induced fractional number. Thus neither is the cosmic string stable nor is the fermion number conserved, yet the bound state then becomes stable due to Quantum Mechanics. The other phenomenon concerns a metastable vacuum getting destabilised due to the presence of a cosmic string. This happens because the scalar field signalling spontaneous symmetry breaking acquires a vacuum expectation value approaching its true vacuum value in the core of the string. Thus the string acts like a seed nucleating the true vacuum. The instanton mediating between the false vacuum and the exit point into the true vacuum is shown to exist and graphically displayed through a numeric calculation. T. Padmanabhan has been a long time friend and was collaborator for early investigations in this direction. I review these works done subsequently with other collaborators as a felicitation to him on his sixtieth birthday.

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Topological defects in the left-right symmetric model and their relevance to cosmology

Cited by 11 publications

References 43 publications

B−Lcosmic strings and baryogenesis

B−Lcosmic strings and baryogenesis

GaugedB−Lsymmetry and baryogenesis via leptogenesis at TeV scale

Stability Longevity and All That: False Vacua and Topological Defects

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