[Hps-analysis] HPS Analysis group meeting August 12 @ 8am/11am PDT/EDT

[Sho Uemura]

I added a new set of plots where I cut on esum>0.8*ebeam, and fit the 
numbers of events with and without positron layer 1 hits.

This gives very reasonable numbers: a=0.65, b=0.58, which is consistent 
with our estimate that the old geometry overestimates WAB conversion by 
~15%. I haven't looked at the new WABs yet, but let's assume that brings b 
up to 0.65.

So then the trident and WAB normalizations agree if you assume the 
detector efficiency is 65% at high esum; you just need to explain what's 
going on at low esum.

Not yet clear which explanation is better:

either

* the detector efficiency is uniform in phase space, and tritrig and WAB 
MC are correct
* a=0.22, b=1.42 (meaning, MC rate normalization is totally wrong)
* MC doesn't get the WAB conversion location right: more conversions 
with L1 hits in data than in MC

or

* the detector efficiency is shaped funny and/or MC is incorrect
* a=0.65, b=0.65

I think the second explanation feels better but it is not complete.

On Fri, 12 Aug 2016, Graham, Mathew Thomas wrote:

> Hi all,
>
> We?ll have a meeting tomorrow?check the agenda here.
>
> https://confluence.slac.stanford.edu/display/hpsg/August+12%2C+2016+DAWG+Meeting<https://confluence.slac.stanford.edu/display/hpsg/August+12,+2016+DAWG+Meeting>
>
> Thanks, Matt&Nathan
>
>