# CandFitShowerEM

## Contents

Chris Smith, Hai Zheng
Package to fit EM shower shapes in MINOS.
Uses CandShowerEM to get strip cluster and initial vertex, angle and energy estimates. A parameterization of EM shower profiles is used to predict the average energy loss in plane, strip coords for the parameters given. A Chi2 is then calculated using a covariance matrix method. The errors and correlation terms have been estimated from MC events, although more work is needed to parameterize these values correctly. Simple brute force fitting can also be carried out by setting step sizes and number of steps for each parameter (energy,x,y,z,dudz,dvdz) such that a chi2 minimum and best params can be found. However, the calculation of the shower shape predictions in plane, strip is quite CPU intensive and so this fitting technique is incredibly slow.
## Input Objects

CandShowerEM
## Output Objects

CandFitShowerEM
Mip Calibration tables + other access via CandStrip, Ugli
Takes arguments to configure step size and number of steps in vertex, angle and energy when fitting. Setting number of steps to 0 for all params forces a single chi2 calculation at the vertex,angle,energy params calculated by CandShowerEM package.
None.

Chris Smith
Last Modified: $Date: 2004/10/05 12:24:36 $