Bayesian approach for the Electron Recoil background model in XENON100.

Agostini F.
  Mercoledì 28/09   16:30 - 19:00   Edificio Psicologia 2 - Aula 2E   III - Astrofisica
XENON100 is a low-background experiment, aiming to detect the elastic scattering of dark matter particles off xenon target nuclei. A consistent part of background is due to electrons or gammas scattering off xenon electrons, generically called Electron Recoils (ER). The background has been treated so far with a phenomenological approach, using the weekly calibration data. In this talk I present a refined study of the ER background, in a Bayesian statistical frame. In particular we test the so-called NEST model, that is used to predict the number of photons (light yield) and electrons (charged yield) emitted by a particle crossing the detector. The light and charge yield are used as input parameters for the likelihood, then the posterior probability is compared with the calibration data, in order to obtain the best estimation of the model and to correctly reproduce the XENON100 response to ER background.