[Halld-tagger] [EXTERNAL] Fwd: meeting today

[Richard Jones]

Hello all,

Here is a brief status update from Andrew Schick. Progress is being made on
this question, more quantitative information will be forthcoming.

-Richard Jones

---------- Forwarded message ---------
From: Andrew Schick <aschick at umass.edu>
Date: Tue, Jun 22, 2021 at 10:30 AM
Subject: meeting today
To: Richard Jones <richard.t.jones at uconn.edu>


*Message sent from a system outside of UConn.*

Hi Richard,

There is a 50% chance I won't be able to make the meeting today due to an
emergency at home--but I may be able to get back in time. I just wanted to
give you a heads up in case I am absent.

The synopsis of my update is this: all qualitative arguments continue to
show that the pion background is low. Current attempts to do a quantitative
analysis, and then subtract the pion background fail because the
preselection cut on the e+e-(p) channel requiring E/p > 0.7 for both tracks
is too high. That cut alone eliminates all pion events that pass both the +
track and - track neural nets below 0.8 probability when you look at either
the pi+pi-p channel or the pi+pi-(p) channel.

The conclusion is that to do a rigorous and quantitative analysis of the
pion background, I have to go to Alex and make a special request for the
2018-01 run period to have a lower E/p preselection cut--we actually need
to increase the pion background to get rid of it.

Hopefully I will be there today to say so.

-Andrew
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