Bs -> mumu Background analysis

Bs -> mumu Background Analysis Antonio Yanez Supervisor: Dr. Diego Martinez Santos August 2011 Outline Introduction Background Curve Fitting Diphotons study Longitudinal momentum assymetry study Conclusions Introduction The Decay The experiment Background Overview The Fit 1 Crystallball for each resonance Bkg: 2 exponential decays Signal region not used Results Diphotons The Origin Fit Fit with cut at pt > 500 MeV/c Range 4000-8000 MeV 3 Components of exponential decay in 2D: mass and life Distribution of lifetime of two NTuples pl asymmetry The variable Fit in the background... ...and in the signal region n1 < 15% Conclusions Ratio of bkg1 ~ 5% Coherent with result These are the results ... and this is what I spent most time doing Thank you very much! Bkg1 is not due to a resonance. The resonances exert no influence on fitting the range above 4000 MeV. Bkg1 is not caused by diphotons. Besides, they are taken away with a cut in pt. The value of momentum asymmetry in signal region is not inconsistent with the two exponential background. Low transverse momentum High life compared to B (1.472 ps) Used to study 2 body decays We found it can be used to distinguish both components of background very suppressed in SM: BR = 3.2e-9 experimental limit 1.1e-8 Very sensitive for NP (SUSY, high tan(beta)) 2010 Background Data (bkg1) (bkg2) ? My horses No idea what the future will bring...