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SUMMARY:The XENON100 exclusion limit without considering Leff as a nuisanc
 e parameter
DTSTART;VALUE=DATE-TIME:20120530T090000Z
DTEND;VALUE=DATE-TIME:20120530T100000Z
DTSTAMP;VALUE=DATE-TIME:20130520T143321Z
UID:indico-event-188236@cern.ch
DESCRIPTION:In 2011\, the XENON100 experiment has set unprecedented constr
 aints on dark matter-nucleon interactions\, excluding dark matter candidat
 es with masses down to 6 GeV if the corresponding cross section is larger 
 than 10^{-39} cm^2. The dependence of the exclusion limit in terms of the 
 scintillation efficiency (Leff) has been debated at length. To overcome po
 ssible criticisms XENON100 performed an analysis in which Leff was conside
 red as a nuisance parameter and its uncertainties were profiled out by usi
 ng a Gaussian likelihood in which the mean value corresponds to the best f
 it Leff value smoothly extrapolated to zero below 3 keVnr. Although such a
  method seems fairly robust\, it does not account for more extreme types o
 f extrapolation nor does it enable to anticipate on how much the exclusion
  limit would vary if new data were to support a flat behaviour for Leff be
 low 3 keVnr\, for example. Yet\, such a question is crucial for light dark
  matter models. To answer this issue\, we use a maximum Likelihood ratio a
 nalysis\, as done by the XENON100 collaboration\, but do not consider Leff
  as a nuisance parameter. Instead\, Leff is obtained directly from the fit
 s to the data. This enables us to define frequentist confidence intervals 
 by marginalising over Leff.\n\narXiv:1203.6823v2\n\nhttp://indico.cern.ch/
 conferenceDisplay.py?confId=188236
LOCATION:CERN TH common room
URL:http://indico.cern.ch/conferenceDisplay.py?confId=188236
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