2020-06-11 analysis¶

Present:
Paul Kyberd
Ken Long
Dan Kaplan
John Cobb
Paul Jurj
Chris Rogers
Tom Lord
Craig Brown

PJ showed us plot of change in emittance with emittance with fit line.

KL: Did you estimate the size of the shift due to Al? PJ: No. The relationship is complicated due to slight differences in beta function.

JHC: Agreement of blue dots and line for LiH is pretty good. No absorber effect is reasonable. Note that the lH2 and no absorber look quite consistent.

DK: One could validate the Al explanation. Encouraged to check.

KL: Showed fits by eye to various lines. Note difference in slope. Propose we do no show "theory line" because agreement is still needing work.

JHC: You could probably even do better.

DK: Why are the error bars smaller than previous version? PJ: Improvements to correction procedure.

DK: How do we describe the error bars; they are partly statistical and systematic? KL: Make sure that the errors are only statistical. PJ: The errors get rather small if we don't include the "systematic" effects. KL: The error is not really "systematic", it is statistical, even though it is "MC statistical".

JHC: Can't get to the MICE note to check his error analysis as mice.iit.edu is down. DK: Working on it. PK: PF has a copy.

PK: Have we agreed that the theory line will not be on the plot? PJ: Yes. PK: Is there a motivation to put a fit line on? KL: will the fit get distorted by corrections.

JHC: What about the suppressed zero? PJ: We don't have enough statistics at low emittance. JHC: would be nice to use additional samples. PJ: yes, it is a work in progress. CR: we won't do it by Monday

DK: Why don't the points have same emittance at TKU? PJ: Fluctuations in the parent distribution tend to pull the plot.

JHC: Fit to the blue points and compare CR: Good idea but we can't do it by Monday. JP: Note that the theory slope is shown on slide 3. DK: note beta changes significantly over the absorber.

JHC: What is the best absorber? PJ: lH2 has smaller eqm emittance. KL: LiH is easier to handle.

JP: To be clear, what do we agree? CR: We agree to keep errors the same with comment on the plot to the effect that there are no systematic errors.

KL: Do the branding carefully! These will live with us for two years.

KL: Watch LH2 in the legend
CR: varepsilon not epsilon
JHC: Horizontal axis starts at 1.0
CR: vertical axis starts at -0.5 mm

JHC, KL, DK, CR: Great plots! Well done for these and also Tom et al!