1. CSC High Pileup Sumulations Vadim Khotilovich Alexei Safonov Texas A&M University June 15, 2009

2. 2009-06-152 Samples situation So far no news from Dave Newbold on progress in centralized production of muon+new tracker samples in FullSim –Last time he wrote he was busy resolving isues with FastSim If it might take too long, we might start production of small CSC+tracker samples at LPC CAF –Need to know what exactly samples are needed first –It would be good to pick up updated/fixed version of LongBarrel Mike Weinberger mentioned last week that they were in process of solving some issues with missing hits We plan on redoing tau+tracker samples soon as well as the LB update will be ready

3. 2009-06-153 CSC Trigger Primitives Code Slava updated CSC L1 emulator code so that now CLCT processing (and LCT) does not stop in first BX where a CLCT was found –More realistic implementation –Important for high luminosities –I have almost finished merging Slava’s update into my code Still ironing out small issues I was mostly busy with work on ME1/1: –ME1a and ME1b separation ‘Naïve’ version works (ME1a and ME1b considered completely separate chambers with “cheating” wire digis) Developing ‘smart’ separation algorithm –Need to update efficiency studies with new code –More on it next

4. 2009-06-154 ME1/1 Reminder In hardware ME1/1 = ME1/a + ME1/b Wire groups –Continuous 1/a+1/b coverage –48 wire groups –Some (#11-16) cross the border It complicates treating 1/a and 1/b as separate logical chambers Strips: –ME1/a and 1/b have separate sets –ME1/a: 48 strips ganged into sets of 3 in current HW –ME1/b: 64 strips ME1/b ME1/a ME1/1  =1.55  =2.09  =2.43

5. 2009-06-155 ME1/1 Issues Crucial for Track Finder PT resolution Most affected at high luminosities –The highest occupancies Especially in ME1/a –Efficiency drops lower then in other chambers Bigger TMB FPGA is needed for algorithm improvement Implementation of strips in ME1/a: –Current “ganged strips” solution is not useful for triggering

6. 2009-06-156 ME1/1 Action Plan Logically separate LCT finding in ME1/a and ME1/b –Un-ganging ME1/a in simulation –Need to estimate A/CLCT occupancies per whole ME11 and its parts Do we need to increase maximum of 2 per ME11? –Develop new algorithms for TMB Improving efficiency of –CLCT finding Reduction of dead-time, taking advantage of bigger future FPGA –TF track finding Investigation of existing high PU inefficiency (when ME1/a not used) –Waiting on Darin for plan; I can help Incorporation of ME1/a

7. 2009-06-157 Number of ALCTs per ME1/1 Use PU400 minbias sample (no neutron BG!) Hack emulator code to print out number of ALCTs with BX=6 before selecting the best two Estimate f(#ALCT>2) = N(#ALCT>2)/N(1≤#ALCT) Very clean exponential distribution! –N i+1 = r N i, r = 0.0605 From geometric sequence properties: –f(#ALCT>2) = r 2 = 0.37% The same number as from data!

8. 2009-06-158 Number of ALCTs per ME1/1 Our f(#ALCT>2) estimate was for minbias sample What would be f(#ALCT>2) for the case of chambers crossed by a signal muon track in high pileup? We can estimate by adding +1 ALCT to chambers –Results in “shifting” bins: 1  2, etc. –Neglect small contribution of gamma rays from real muons –Neglect nonlinear effects from overlapping signals from muon and pileup –As f(#ALCT>2) depends only on ratio of two neighboring bins f(#ALCT>2) = 0.37% should stay the same

9. 2009-06-159 Number of CLCTs per ME1/1 Complications: –There are two separate parts: ME1/a and ME1/a –emulator only finds the best and the second best CLCT No “before selecting the best two” number available Run two independent CLCT finders in ME1/a and ME1/b –Each finds 2 max CLCTs (with deadtime artificially removed) –For ME1/1 print sum of results from ME1/a and ME1/b Assume: distributions for CLCTs obey exponential law –Need to consider that overflow i>2 bins are now added to N 2 –Then r = N 2 /N 1 becomes r = N 2 /(N 1 +N 2 ) and still f(#CLCT>2) = r 2 N1N1 N2N2 rf(#CLCT>2) ME1/a1451612190.0770.60% ME1/b96715870.0570.33% ME1/12326822400.0880.77%

10. 2009-06-1510 # A/CLCTs per ME1/1: Summary Estimated fraction of cases for PU400 when there are more than two A/CLCTs with relation to the number of cases when there are at least one A/CLCT: –ALCTs: 0.4% –CLCTs: 0.8% Can we consider those numbers sufficiently small? –If so, we don’t really need to increase maximum of 2 per ME11 –One thing to take into account: occupancies in ME1/a are much higher than in all other chambers E.g., comparing absolute values, what is 0.8% in ME11 could be 20% or so in ME2/2

11. 2009-06-1511 Towards better ME1/a and ME1/b Separation ALCTs are reconstructed in whole ME11 –They are angled at 29 o Need to define how we assign an ALCT to ME1/a or ME1/b Plots show halfstrip number (x) vs. wire group number (y) for LCTs that were matched to SimTrack –Already from these plots can create look-up tables –More rigorous is to calculate from the geometry Have it too