Monte Carlo Independent Lifetime Fitting at LHCb in Lifetime Biased Channels

Lifetime measurements at LHCb will help in detector calibration as well as providing constraints on lifetime differences in the $B_s$ system and other theoretical models. In order to exploit the full range of decays available in LHCb, it is important to have a method for fitting lifetimes in hadronic channels, which are biased by the impact parameter cuts in the trigger. We have investigated a Monte Carlo simulation independent method to take into account the trigger effects. The method is based on calculating event by event acceptance functions from the decay geometry and does not require any external input. This note presents current results with this method for both the full LHCb Monte Carlo for the channel $B^{0}_{d} \rightarrow D^{-} \pi^{+}$ and a toy Monte Carlo for the same channel, including a discussion of the expected statistical precision on lifetime measurements using this method once LHCb is operational.