STAR HardProbes PWG

[Carl Gagliardi <c-gagliardi AT tamu.edu>]

Hi All—

 

A while ago I realized that the mid-rapidity EMC gains are lower than “nominal,” making our effective BEMC/EEMC thresholds higher than we had intended (or they were during 2015).  At the time, I guesstimated that the gain difference was 15~20%.  To be conservative, I suggested shifting the various trigger thresholds by ~16%, and that’s what we did.

 

Now that we have more data and I’ve had a better chance to look at it systematically, it appears that our current thresholds are still higher than “desired” by ~5%.  In other words, the effective JP2 E_T threshold is around 7.7 GeV, whereas it was 7.3 GeV during 2015.  Similar scaling applies for the other EMC-based JP and HT triggers.

 

Should we adjust thresholds again or live with them as they are?  At this late date, my gut says we should leave them alone.  However, some of you might have good arguments to make another round of threshold adjustments, at least for some of the triggers.  So I’m sending this message to a bunch of different physics-related and operations-related e-mail lists.

 

Speak now or forever hold your peace!

 

Stay Healthy!

Carl