Track error covariance matrix

XSIG (I)

.TRUE. if covariance matrix available

QSIG (I,N,M)

element (N,M) of the covariance matrix N,M = 1,2,3,4 in the order QX,QY,QZ,QE

QSIGEE (I)

Error² on energy

QSIGE (I)

Error on energy

QSIGPP (I)

Error² on momentum

QSIGP (I)

Error on momentum

QSIGMM (I)

Error² on mass

QSIGM (I)

Error on mass The mass error is not defined for particles with mass = 0.

QSIG (I,1,1) is set to -1 if the matrix is not available.