arXiv subjects

Palash B. Pal

Publications and source records attributed to Palash B. Pal.

76 records · Page 5Linked to original sources

arXiv1993

Loop-Induced Majoronic Decay of Neutrinos:

In models where the suppression of the tree level couplings of fermions with Goldstone bosons is not protected by symmetry, the loop-induced couplings can in general dominate over the tree couplings. We demonstrate this by calculating the decay $ν\to ν' + \mbox{Majoron}$ in the simplest singlet Majoron model. It is shown that 1-loop contributions can be orders of magnitude bigger than the tree-level result, and hence allows a wide range of interesting values of neutrino mass and mixing to be compatible with cosmological constraints.

hep-ph↗

arXiv1993

Rare K-Decays as Crucial Tests for Unified Models with Gauged Baryon Number:

In the grand-unified models based on SU(15) and SU(16) in which the quarks and leptons are un-unified at the intermediate stages, we show that ${\rm BR}\; (K_L \to μe) \leq 10^{-14}$ and ${\rm BR}\; (K^+ \to π^+μe) \leq 10^{-14}$ despite the presence of leptoquark gauge bosons. Thus, the observation of these processes in the ongoing or upcoming experiments will rule out the models.

hep-ph↗

arXiv1992

Implications of LEP Results for SO(10) Grandunification with Two Intermediate Stages

We consider the breaking of the grand unification group $SO(10)$ to the standard model gauge group through several chains containing two intermediate stages. Using the values of the gauge coupling constants at scale $M_Z$ derived from recent LEP data, we determine the range of their intermediate and unification scales. In particular, we identify those chains that permit new gauge structure at relatively low energy $(\sim 1\, {\rm TeV})$.

hep-ph↗

arXiv1992

SU(16) grandunification: breaking scales, proton decay and neutrino magnetic moment

We give a detailed renormalization group analysis for the SU(16) grandunified group with general breaking chains in which quarks and leptons transform separately at intermediate energies. Our analysis includes the effects of Higgs bosons. We show that the grandunification scale could be as low as $\sim 10^{8.5}$ GeV and give examples where new physics could exist at relatively low energy ($\sim 250$ GeV). We consider proton decay in this model and show that it is consistent with a low grandunification scale. We also discuss the possible generation of a neutrino magnetic moment in the range of $10^{-11}$ to $10^{-10}μ_B$ with a very small mass by the breaking of the embedded SU(2)$_ν$ symmetry at a low energy.

hep-ph↗