L2gamma2008 trigger strawman

10/23/2007

Before I put alot (any) time in on the L2gamma trigger for 2008, I'm putting up a strawman proposal.  Here are some of the constraints that I noted during the analysis meeting --

1. L2gamma will have one trigger bit assigned
2. So we can't run seperate instances of the algorithm as in 2006.
3. Plan to run two thresholds: 6 GeV in the EEMC, and 7-8 GeV in the BEMC
4. Goal is 5 Hz trigger rate summed over both calorimeters
5. Prefer a smaller tower cluster, eg 2x1 (but 2x2 acceptable?)

In 2006 and 2007, the L2gamma trigger searched for the first cluster which satisfied the trigger requirements: high tower above one threshold, 3x3 cluster patch above a second threshold.

Strawman proposal for 2008 is attached as a PDF.  Things which are relatively "settled" have a yellow background.  Things which aren't have a green background.  In the latter category are things like what do we want to save at L2 in terms of variables, and whether or not we want the flexability to do an isolation cut at L2.

Outcome of discussion on gamma phone

10/24/2007

1. Use a 2x2 cluster, absent simulation which shows good efficiency with 2x1.
2. Towers belonging to cluster will be identified by denoting which diagonal tower adjacent to the seed tower belongs to the cluster.
3. Code should have the option to correct the cluster ET based on vertex position as determined by the BBC
4. L2vertex algorithm is a nice project looking for a home...
5. Discussed isolation cut as an alternative to raising thresholds during the run.  Met with less resisitance than usual.  Time permitting, this capability should be added to the trigger code w/ appropriate montoring and such.