Kinematic fitting

None of the functions described below can work when reading a NANO-Dst ,

Performs a mass-constrained fit for the decaying particle ITK. This fit readjusts the 4-vector of ITK by using the constraint E² - p² = mass('part-name')² (method: Lagrange multiplier). In particular, the fit improves the 3-momentum resolution. KVFITM determines the 4-momentum of the decaying particle only; the 4-vectors of the decay products are not recalculated and remain unchanged. Therefore, the momenta of the daughter particles will not add up to the fitted momentum of the mother exactly.

This function is similar to KVFITM. It is intended to be used inside loops over particles and antiparticles. The particle given by `part-name' is used if IANTI is 0; the corresponding antiparticle is used if IANTI is nonzero.

The $\chi^{2}_{}$ for the track fit may be accessed with the statement function QMCHIF(IFIT) .