On the treatment of energy loss in track fitting

As the energy loss of electrons in matter is described by a strongly non-Gaussian distribution, the Kalman filter is not necessarily the optimal procedure for the fitting of electron tracks. We show that the momentum resolution can be improved by using nonlinear methods, such as the Gaussian-sum filter and the Metropolis-Hastings algorithm. We report results of a simple simulation experiment and comment on the respective merits of these methods. (C) 1998 Elsevier Science B.V.