The Pion Formfactor Experiment

Missing Mass Check for Production Run

(1) Introduction

Since Tanja find that Maybe HMS momentum has an offset of about 1.5 unit, it is necessary to check Missing Mass in production Run to see if they also agree with this.

(2) Tables for fpi2 sieve slit runs

Table.1 MissMass for production Run.

Run Number Ebeam Psos theta_pi P_pi Missmass

47067 4210 0.771 10.54 3.336 0.9354+-0.0001

47120 4210 0.771 12.2 3.336 0.9351+-0.0001

47358 5248 1.74 13.61 3.336 0.9365+-0.0001

47394 5248 1.74 16.61 3.336 0.9374+-0.0001

47421 5248 1.74 10.61 3.336 0.9362+-0.0001

47593 3778 0.786 10.50 2.931 0.9351+-0.0001

47601 3778 0.786 12.54 2.931 0.9359+-0.0001

47691 4709 1.65 13.29 2.931 0.9383+-0.0001

47701 4709 1.65 16.29 2.931 0.9388+-0.0001

47735 4709 1.65 10.55 2.931 0.9375+-0.0001

(2) BPM correction and Radiation Correction?

This will be done after fpi2 meeting.

(3) Conclusion

It looks like that HMS does have offset on P, but we need BPM correction and Radiation Correction to get consistant results and conclusions.

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Run Number	Ebeam	Psos	theta_pi	P_pi	Missmass
47067	4210	0.771	10.54	3.336	0.9354+-0.0001
47120	4210	0.771	12.2	3.336	0.9351+-0.0001
47358	5248	1.74	13.61	3.336	0.9365+-0.0001
47394	5248	1.74	16.61	3.336	0.9374+-0.0001
47421	5248	1.74	10.61	3.336	0.9362+-0.0001
47593	3778	0.786	10.50	2.931	0.9351+-0.0001
47601	3778	0.786	12.54	2.931	0.9359+-0.0001
47691	4709	1.65	13.29	2.931	0.9383+-0.0001
47701	4709	1.65	16.29	2.931	0.9388+-0.0001
47735	4709	1.65	10.55	2.931	0.9375+-0.0001