Sridhara Dasu115 April 2002 L1CaloTrigger Algorithms Sridhara Dasu University of Wisconsin Algorithms: Details, Updates and Simulation - 2 x cm -2 s -1 studies (CMS IN 2002/19) - Highlights -Good jets and H T - What will be implemented in GCT/GT -Unexplored features - invitation to participate -Define LUTs etc. in RCT, GCT -Define GT algorithms

Sridhara Dasu215 April 2002 Overview BU/PU TPG RCT GCT GT

Sridhara Dasu315 April 2002 Calorimeter Geometry EB, EE, HB, HE map to 18 RCT crates Provide e/  and jet,  E T triggers

Sridhara Dasu415 April 2002 Trigger Mapping

Sridhara Dasu515 April 2002 Electron/Photon Algorithm

Sridhara Dasu615 April 2002  / Jet Algorithm

Sridhara Dasu715 April 2002 Tower Level Memory LUT Lookup table for arbitrary nonlinear transform - including making E+H and H/E 8-bit nonlinear EM E T 8-bit nonlinear HD E T 1-bit EM fine-grain bit 7-bit linear E T 9-bit linear E T 1-bit Activity 1-bit H/E, FG Veto Electron Jet /  Fully programmable LUT, Current default values: - Electron scale: 0.5 GeV LSB, E max =63.5 GeV - Veto: OR of fine-grain veto and H / E < 5% - Jet /  scale (E+H): 1.0 GeV LSB, E max =511 GeV - Jet energy (12x12 tower sum), E max =1 TeV - Activity level for  pattern: E > 2 GeV, H > 4 GeV

Sridhara Dasu815 April 2002 Missing / Total E T Algorithm 20 o 0o0o 40 o 360 o ……   E T 18 E x 18 E y 18 ET2ET2 Ex2Ex2 Ey2Ey2 ET1ET1 Ex1Ex1 Ey1Ey1 ETET ME T Strip E T sum over all  LUT For sums E T scale LSB (quantization) ~ 1 GeV is used  = 20 o used instead of HCAL tower size:  = 5 o

Sridhara Dasu915 April 2002 Trigger Rates Vs Threshold

Sridhara Dasu1015 April 2002 Trigger Efficiency Turn-on

Sridhara Dasu1115 April 2002 Cal Trigger Rates: 2 x cm -2 s -1 Selected Scenario: 5 kHz e/g, 5 kHz ,jets, 1 kHz combined, rest 

Sridhara Dasu1215 April 2002 Physics Efficiency: 2 x cm -2 s -1 Scenario: 5 kHz e/ , 5 kHz ,jets, 1 kHz comb, rest  No generator level cuts other than requiring trigger objects within calo. (  <5) or tracker (e,  ) acceptance

Sridhara Dasu1315 April 2002 Good Jets L1CaloTrigger finds jets of three types –Central, Forward and  jets We send GT 4 objects of each type These are mutually exclusive lists For pure jet triggers, we need to use objects from all three categories, i.e., combine and re-sort Although, this is easy to implement in software, we will use too many GT algorithm slots –Use good jet (E T >Threshold) counts Can count within programmable  cuts –Several counts available –For example: 2 jets in central, 1 in +forward, 1 in -forward Need simulation studies to define what is useful

Sridhara Dasu1415 April 2002 H T Trigger Total scalar E T integrates too much noise and is not easily calibrated –At L1 tower-by-tower E T calibration is not available However, jet calibration is available as f(E T,  ) Therefore, H T which is the sum of scalar E T of all high E T objects in the event is more useful for heavy particle discovery/study –SUSY sparticles –Top GCT should be able to implement it (FPGAs + flexible backplane) –Use top 8 or 12 candidates in sorted good jet list –Sum E T of good jets with E T >threshold (e.g., 10 GeV)

Sridhara Dasu1515 April 2002 GCT/GT Algorithm Agreement H T from GCT to GT on separate cable in same format as E T Study jet counts with an eye towards increasing numbers and categories –Works on good* jets (E T cut) *Should include all 3 categories (C + F +  ) –Decide by June CMS Trigger Meeting Jets are calibrated with LUTs Keep 4 x (C + F +  ) = 12 Jet List to GT

Sridhara Dasu1615 April 2002 Summary RCT preproduction prototypes implementing the algorithms and programmability as described in this talk are built –The default values for LUTs coded in ORCA perform quite well for discovery physics –Need to further optimize the use of L1 LUTs GCT will implement good jet counts with cuts on various  and  regions, and H T trigger –Need to explore the use of the jet counts for use in multi- jet physics events Will help save some GT algorithms Topological trigger cuts in GT –Jim Brooke started exploring  cut for WW fusion L1 group will be happy to help anyone interested in optimization of cuts to improve trigger performance.