[BLASTTALK] correction to: momentum fit as a function of momentum

From: Timothy P. Smith (Timothy.P.Smith@Dartmouth.EDU)
Date: Wed Mar 31 2004 - 17:01:32 EST


I have think that I messed up this morning - I knew that the
correction
parameters were too large. So I've rechecked myself. I
should be looking
at P_fit vs. P_calc and fit this correlation. I like my
afternoon results much
better - even if they are not so bold.

plot
[1][2][3]
[4][5][6]

1) P_left vs. Theta_left (same as wc_res.C)
2) P_fit - P_ideal (same as wc_res.C) sigma = 33.8MeV/c
3) P_corrected - P_ideal sigma = 29.6 MeV/c
4) P_fit vs. P_ideal <- note the cut I'll use
5) fit line to P_fit vs. P_ideal
6) (P_corrected - P_ideal)*100%/P_corrected sigma = 3.1%

Note that the mean value of plot 2 (original) has gone to
almost zero in plot 3.

I think this same effect would happen if the field was off by 6%

The correction I used was simply,

p_correction = 0.0626 + 0.9445*p_fit

This plot is Hydrogen. I expect I need better elastic cuts,
 and also to look at
the dependences on theta, phi, z.

Tim

______________________________________________________________
Timothy Paul Smith Assistant Research Professor
Dartmouth College, Physics (603)646-9346[phy] -0659[ISTS]
6127 Wilder, Hanover, NH 03755 timothy.p.smith@dartmouth.edu
      
        


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