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Subhendu Rakshit

Publications and source records attributed to Subhendu Rakshit.

26 records · Page 2Linked to original sources
arXiv2004

Neutrino masses in R-parity violating supersymmetric models

We study neutrino masses and mixing in R-parity violating supersymmetric models with generic soft supersymmetry breaking terms. Neutrinos acquire masses from various sources: Tree level neutrino--neutralino mixing and loop effects proportional to bilinear and/or trilinear R-parity violating parameters. Each of these contributions is controlled by different parameters and have different suppression or enhancement factors which we identified. Within an Abelian horizontal symmetry framework these factors are related and specific predictions can be made. We found that the main contributions to the neutrino masses are from the tree level and the bilinear loops and that the observed neutrino data can be accommodated once mild fine-tuning is allowed.

hep-ph↗
arXiv2002

Radiative production of invisible charginos in photon photon collision

If in a supersymmetric model, the lightest chargino is nearly degenerate with the lightest neutralino, the former can decay into the latter alongwith a soft pion (or a lepton-neutrino pair). Near degeneracy of the chargino and neutralino masses can cause the other decay products (the pion or the lepton) to be almost invisible. Photon-photon colliders offer a possibility of clean detection of such an event through a hard photon tag.

hep-ph↗
arXiv2001

Trilinear Neutral Gauge Boson Couplings

We study the CP even trilinear neutral gauge boson vertices at one-loop in the context of the Standard Model and the Minimal Supersymmetric Standard Model, assuming two of the vector bosons are on-shell. We also study the changes in the form-factors when these two bosons are off-shell.

hep-ph↗
arXiv2001

Muon anomalous magnetic moment confronts exotic fermions and gauge bosons

We investigate the status of models containing exotic fermions or extra Z-like neutral gauge bosons in the light of the recent data on anomalous magnetic moment of muon. We find that it is possible to extract interesting bounds on the parameters characterizing such models. The bounds are particularly strong if the new flavour-changing neutral currents are axial vectorlike.

hep-ph↗
arXiv2000

Cosmological constraints on R-parity violation from neutrino decay

If the neutrino mass is non-zero, as hinted by several experiments, then R-parity-violating supersymmetric Yukawa couplings can drive a heavy neutrino decay into lighter states. The heavy neutrino may either decay radiatively into a lighter neutrino, or it may decay into three light neutrinos through a Z-mediated penguin. For a given mass of the decaying neutrino, we calculate its lifetime for the various modes, each mode requiring certain pairs of R-parity-violating couplings be non-zero. We then check whether the calculated lifetimes fall in zones allowed or excluded by cosmological requirements. For the latter case, we derive stringent new constraints on the corresponding products of R-parity-violating couplings for given values of the decaying neutrino mass.

hep-ph↗
arXiv2000

Some low energy effects of a light stabilized radion in the Randall-Sundrum model

In this paper we study some low energy effects of a light stabilized radion in the Randall-Sundrum scenario. We find that the NLC 500 with its projected precision level will be able to probe the radion contribution to the anomalous magnetic moment and electric quadrupole moment of W boson for values of radion vev up to 500 Gev. On the other hand the BNL experiment E821 will be able to test the radion contribution to $a_μ$ for 1 Tev radion vev and $m_ϕ\le m_μ$. We have also shown that the higgs-radion mixing induces a 2.6% correction in the WWh coupling. Finally by comparing the radionstrahlung with the higgsstrahlung process we have found that the LEPI bound on the higgs mass based on $Z\to hl\bar{l}$ decay mode suggests a lower bound of about 35 Gev on the radion mass.

hep-ph↗
arXiv1999

R-parity-violating trilinear couplings and recent neutrino data

The nontrivial structure of the neutrino mass matrix, suggested by the recent Super-Kamiokande results and data from other neutrino experiments, can be reproduced in R-parity-violating supersymmetric theories. This requires sets of products of R-parity-violating trilinear couplings to take appropriately chosen values. It is shown that the existing constraints on these couplings are satisfied by these choices.

hep-ph↗