Other vertex (and kinematic) fitters in basf2
Contents
7.5.2. Other vertex (and kinematic) fitters in basf2#
Use cases#
Vertex fit of multiple particles
Vertex fit of multiple particles with mass constraint
Vertex fit of multiple particles with direction constraint
Fit of decay chains (with constraints)
Vertex fit of a V0 (with constraints)
Vertex fit of tag B (with constraints)
Momentum fit of a \(\pi^0\)
Kinematic fits of multiple particles with full or partial soft or hard (four momentum) constraints.
Kinematic fits of multiple particles with full or partial soft or hard (four momentum) constraints with partially or completely missing particles.
RAVE#
Rave is a Kalman-based vertex fitter implemented as an external library (CMS vertexing library)
Physics Use Case
Standard kinematic fit
Mass fit from mother 7x7 error matrix
Refit of the daughters
Geometric fit
Tag Vertex
basf2 implementation
Kinematic fit included in ParticleVertexFitModule
Module for geometric fit not available but can be easily developed
TagVertex
V0Finder vertex fit implemented in tracking code
Issues
Very slow: external libraries (Root) and shell
no developers
RAVE: global
RAVE algorithm to be tested
RAVE API to be developed and tested
RAVE API kinematic constraints to be tested and/or debugged
RAVE: progressive
Algorithm should be developed inside RAVE
Progressive: References are missing
General RAVE development
KFit#
Port of the Belle vertex fitter.
Physics Use Case
Standard Kinematic Fit
Mass fit from daughters
Constrain the sum of four momentum of all final particles to that of e+ e- beams
basf2 implementation
Kinemeatic fit available in ParticleVertexFitModule
Issues
4C constraint not completed
OrcaKinFit#
Kinematic fitter implementation, based on a fork of MarlinKinFit with modifications (remove all ILC dependency).
Physics Use Case
Momentum constraints (soft and hard) with and without (partially) missing particles. Arbitrary constraints (e.g., recoil mass: BELLE2-NOTE-PH-2017-002)
TagV#
Module to perform the Btag vertex geometric fit using the RAVE adaptive vertex fitting algorithm. It takes as input the tracks
of the Rest Of Event. More info about interface in TagVertex
, vertex.TagV
Physics Use Case
TDCPV measurements