Element# : Track number. TBPUT by : Smearing routine.(SMRCVT) Contents : CDC-VTX combined track information. Format : R*4, R*8, I*2, & I*4 mixed fixed length (55)
RBUF(1-3)=Í<>px, py, pz. (4)=Í<>E assuming massless particle. (5-7)=Í<>x, y, z of closest approach to the beam axis. IBUF(9)=ápparent charge ( +/-1 ) RBUF(11-15)=d(cm), (radian), (GeV-1), dZ(cm), and of track parameter. (16-18)=Pivot of track parameter, X0, Y0, and Z0. DBUF(10-24)=érror matrix (lower triangle only) RBUF(49)=not used ( reserved for confidence level ) (50)=not used ( reserved for ) HBUF(1,51)=Number of degrees of freedom. (2,51)=not used ( reserved for duplicate flag ) (1,52)=Number of track parameters ( 5 for helices ) IBUF(53)=Track type (54)=pointer to "Production:CDC;Track_Parameter" (55)=pointer to "Production:VTX;Space_Point"
The first 52 words have the same meanings as those of "Production:CDC;Track_Parameter". The track type is the number of linked VTX hits, if positive. Otherwise, it signals the failure of combined fitting.
|track type||=||-1 to 0 :||identical to the corresponding CDC track|
|=||2 :||CDC-VTX combined track|
Notice that there is a one-to-one correspondence between CDC tracks and CDC-VTX combined tracks: CDC track #i corresponds to CDC-VTX track #i. At present, no actual fitting is performed, instead, the track is assumed to pass exactly through the VTX hit positions and to have the momentum given by CDC.