The preliminary FSU Momentum Correction for FroST

The topology γ p -> p π+ π-()

The equation of the momentum correction for FROST

The correction factor for the momentum correction

We have decided the correction factors for the momemtum correction in only momemtum bins. This is the preliminary version. After applying all corrections, we will apply them in angles(θ and φ) ,if we need. If you want to know bins's ranges used in FSU version, click this .

For the proton

θ	φ	momentum(MeV)	correction factor
0	0	1 ( 200 - 500 )	1.012011
0	0	2 ( 500 - 600 )	1.002014
0	0	3 ( 600 - 700 )	0.999716
0	0	4 ( 700 - 900 )	1.000439
0	0	5 ( 900 - )	0.999975

For the photon

θ	φ	momentum(MeV)	correction factor
0	0	1 ( 200 - 500 )	1.0000
0	0	2 ( 500 - 600 )	1.0000
0	0	3 ( 600 - 700 )	1.0000
0	0	4 ( 700 - 900 )	1.0000
0	0	5 ( 900 - )	1.0000

For the π+

θ	φ	momentum(MeV)	correction factor
0	0	1 ( 50 - 200 )	1.005510
0	0	2 ( 200 - 270 )	0.998049
0	0	3 ( 270 - 350 )	0.998151
0	0	4 ( 350 - 530 )	1.000716
0	0	5 ( 530 - )	1.001858

For the π-

θ	φ	momentum(MeV)	correction factor
0	0	1 ( 50 - 200 )	1.018893
0	0	2 ( 200 - 270 )	0.987956
0	0	3 ( 270 - 350 )	0.986561
0	0	4 ( 350 - 530 )	1.010072
0	0	5 ( 530 - )	0.992872

The Resolution parameters for the covariance matrix

The covariance matrix found in the TBER bank is determined from tracking information only. It is not include the effect of multiple scattering or energy loss in projecting back to the vertex. The resolution parameters are used for the covariance matrix to have these effects. The particle experiences these effects prior to reaching the tracking region of CLAS. ( Kinematic Fitting in CLAS ) Because the FroST experiment uses three kinds of targets, three kinds of resoultion parameters are needed. The following table has the resolution parameters of the covariance matrixes in the butanol, carbon, and CH2. To use these parameters, I fixed the KFitUtils.C in the cobra a little ( This is the COBRA version I use now. )

\	mom	λ	φ
proton	BUT / C / CH2	BUT / C / CH2	BUT / C / CH2
π	BUT / C / CH2	BUT / C / CH2	BUT / C / CH2

The Pull distribution

The following table is the mean and sigma of pulls. The first 10 variables are for butanol. Another 10 variables for Carbon. And the last 10 for CH2. As my decay mode is γ p -> p π+ π-, we need variables for proton, π+, π-, and γ in each target. The first 3 variables for proton, the next 3 variables for π+, the next 3 variables for π-, and the last one is for γ in each target. Each particle in each target has three variables; momentum, λ, and φ except the photon.