Biennial Report 2005-2007 - Saha Institute of Nuclear Physics

8 Biennial Report 2005-071.2.2.6 R-parity violation in NMSSMWe have studied a novel mechanism of neutrino mass generation in the Next-to-Minimal supersymmetricmodel. In the Minimal Supersymmetric Standard Model with bilinear R-parity violation,only one neutrino eigenstate acquires a mass at tree level, consequently experimental data on neutrinoscannot be accommodated at tree level. We show that in the Next-to-Minimal extension,where a gauge singlet superfield is added to primarily address the so-called µ-problem, it is possibleto generate two massive neutrino states at tree level. Hence, the global three-flavour neutrinodata can be reproduced at tree level, without appealing to loop dynamics which is vulnerable tomodel-dependent uncertainties. We give analytical expressions for the neutrino mass eigenvaluesand present examples of realistic parameter choices.G Bhattacharyya, A Abada†, G Moreau†Theo1.2.2.7 Radiactive neutrino decay and CP violation in R-parity violating SupersymmetryWe have calculated the radiative decay amplitude for Majorana neutrinos in trilinear R-parityviolating supersymmetric framework. Our results make no assumption regarding the masses andmixings of fermions and sfermions. The results obtained are exemplary for generic models withloop-generated neutrino masses. Comparison of this amplitude with the neutrino mass matrixshows that the two provide independent probes of CP-violating phases.G Bhattacharyya, PB Pal, H Päs†, TJ Weiler†Theo1.2.2.8 PDF and scale uncertainties of various DY distributions in ADD and RSmodels at hadron collidersIn the extra dimension models of ADD and RS we study the dependence of the various partondistribution functions on observables of DrellYan processes to NLO in QCD at LHC and Tevatronenergies. Uncertainties at LHC due to factorisation scales in going from leading to next-to-leadingorder in QCD for the various distributions get reduced by about 2.75 times for a µ F range 0.5Q< µ F