Calibration of the detector performance
Purpose for taking the calibration dataOne of the most essential points of this experiment is the estimate of the Ke2 and Kμ2 acceptance of the detector. It is very relevant to the stopped K+ method of the proposed experiment, in which the acceptance is primarily determined by the finite solid angle of the detector system in contrast to the in-flight decay experiments where there is no such constraint but issues of difficult kinematical separation exist.
We will perform a full Monte Carlo simulation based on a reliable code, and that the validity of the simulation can be checked against existing data of various observables (not necessarily the acceptance itself) from KEK-PS and possibly with E36 data. While we cannot avoid relying partially on Monte Carlo simulations, it is desirable to support the calculations of the acceptances using data. We discuss the various possible methods to estimate the acceptance ratio using the existing data or future calibration data from E36. This gives us a more reliable estimate of the associated uncertainties.