Muon Trigger and Tracking Improvements with GEMs at

Muon Trigger and Tracking Improvements with GEMs at High Eta (a CSCTF perspective) I. K. Furić for the CSCTF team

Overview • CSCTF trigger system design basics • pipe dream(? ): L 2 resolution performance in the L 1 trigger system • CSCTF system upgrade • points to investigate MPGD contribution I. K. Furić, CSCTF + MPGD GEMs for CMS High Eta Jun 24, 2011 2

CSCTF Current Data Flow ~ hit φ positions ~ hit r positions • • • multi-step analysis and reduction designed for “low” occupancy in high occupancy environment, 3 primitives per station per 30° sector may become a bottleneck pull all stops - allow all L 1 primitives into Sector I. K. Furić, CMS Muon Trigger Phase 1 Jun 24, 2011 Processor Upgrades 3

CSCTF algorithm, in a nutshell • pattern recognition: check for series of L 1 primitive “hits” (LCTs) within Δφ, Δη windows • assign track “mode” based on LCT information • LUTs for p assignment are fully customizable per track “mode” • we can use • one Δφ to “high” precision • multiple Δφ combinations • one Δφ and a muon stub pointing angle T I. K. Furić, CSCTF + MPGD GEMs for CMS High Eta Jun 24, 2011 4

MPGD usage 1: redundancy • current CSC system has • • • no ME 4/2 coverage notice: around η~1. 6, a muon can “sneak” through cracks in stations 2 and 3 this leaves us with only one pair of hits, ie only one Δφ measurement to estimate p. T real situation, illustrates problem of using a hobbled detector in trigger I. K. Furić, CSCTF + MPGD GEMs for CMS High Eta Jun 24, 2011 5

High Rate for Eta = 1. 5 I. K. Furić, CSCTF + MPGD GEMs for CMS High Eta Jun 24, 2011 6

What is going on ME 1/2 6. 7 Ge. V/c 2. 5 Ge. V/c ME 1/1 ~2. 0 Ge. V/c • two-station tracks (missing ME 4/2) • magnetic field return causes ambiguity in Δϕ • situation not much different for ME 1 - ME 3 • fourfold ambiguity as we cross ME 1/1 ME 1/2 • need more information to disentangle I. K. Furić, CSCTF + MPGD GEMs for CMS High Eta Jun 24, 2011 7

Problem resolution • ME 1/1 vs ME 1/2 ambiguity resolved through additional track “modes” • ambiguity due to trajectory reversal in B field not resolved, still need ME 4/2 information • resort to cut hard on Δη, muon stub angle in chamber (LCT pattern) • trade-off: low p program suffers inefficiency • N. B: this is not the only way the system can fail • example: ME 1/1 information crucial for p assignment, parts were/are offline • if systems can cross-communicate, the whole T T for CMS High Eta Jun 24, 2011 trigger is more robust GEMs [again: redundancy] I. K. Furić, CSCTF + MPGD 8

Flexible system exercise: integration of DT pointing • DT overlap also tricky • 2 -LCT tracks suffer same reversal problem • combining information across systems • can misalignment be an effect ? • • (actually, no - systems are off from nominal by max ~ 1 halfstrip width, does not matter) so, how do we improve? it turns out that the DT system reports the direction of the muon stub in the station in great detail - very useful information in barrel region I. K. Furić, CSCTF + MPGD GEMs for CMS High Eta Jun 24, 2011 9

DT Overlap - pointing I. K. Furić, CSCTF + MPGD GEMs for CMS High Eta Jun 24, 2011 10

Can we use CSC pointing? I. K. Furić, CSCTF + MPGD GEMs for CMS High Eta Jun 24, 2011 11

DT Overlap p. T Assignment I. K. Furić, CSCTF + MPGD GEMs for CMS High Eta Jun 24, 2011 12

• CSCTF [high. Reminders η triggers] performance strongly relies on information redundancy • system coverage is at the bleeding edge - loss of chambers in key regions can hurt a lot • systems already cross-talk in order to coverlap region, flexible algorithms allow inclusion of new information [pointing info was not in TDR] • when designing upgrade, try to keep data xfer options as open as possible and algorithms flexible in the worst case “only” gain system GEMs for CMS High Eta Jun 24, 2011 I. K. Furić, CSCTF + MPGD 13 robustness •

CSCTF Upgrade Motivation Current System • momentum assignment pretty good, possibly limited by LUT address space • concern - possible high occupancy in forward region • improve p assignment if possible • recover efficiency at 30° trigger sector borders T I. K. Furić, CMS Muon Trigger Phase 1 Upgrades Jun 24, 2011 14

CSCTF Data Flow Upgrade I. K. Furić, CMS Muon Trigger Phase 1 Upgrades Jun 24, 2011 15

Track finding algorithm • current design - ϕ comparisons, does not scale • well switch to pattern matching system for upgrade I. K. Furić, CMS Muon Trigger Phase 1 Upgrades Jun 24, 2011 16

I. K. Furić, CMS Muon Trigger Phase 1 Upgrades Jun 24, 2011 17

I. K. Furić, CMS Muon Trigger Phase 1 Upgrades Jun 24, 2011 18

CSCTF Data Flow Demonstrators Upgrade CSCTF Sector Processor RX Prototype I. K. Furić, CMS Muon Trigger Phase 1 Upgrades Upgrade Muon Port Card TX Prototype Jun 24, 2011 19

Upgrade Status • we believe we can pipe all currently reported chamber information into SP units • data transfer prototype tests successful • further, we believe we can handle the data load and perform at the pattern recognition stage so far, mockups show that mezzanines with large numbers of pins are feasible algorithm tests performed with CMSSW emulator [bitwise identical output to hardware] can we improve p. T resolution significantly? I. K. Furić, CMS Muon Trigger Phase 1 Jun 24, 2011 can we. Upgrades use MPGD information and where? • • 20

Towards best possible p. T assignment • starting point: information available to current TF • how can we extract the most from it? • feed hit positions into L 2 HLT fit, see if/how we can encode that into our LUTs • full precision position too fine to encode all possible combinations • need rough estimate + post-processing • current system does not support post-processing - LUTs outputs wired straight to board outputs I. K. Furić, CMS Muon Trigger Phase 1 Upgrades Jun 24, 2011 21

CSCTF + MPGD • how to improve endcap muon L 1 resolution? • full offline hit position resolution? (MPGD) • precise pointing information? • MPGD + CSC key layer • CSC upgraded ALCT + TMB • combination of the two? • Upgraded CSCTF has capacity to import RPC hits at expense of CSC LCTs - 4/8 fibers no crosstalk option - cracks at sector boundaries GEMs for CMS High Eta Jun 24, 2011 I. K. Furić, CSCTF + MPGD • 22

p. T Assignment Current • • • best possible - load L 1 trigger primitives into offline Kalman fit testing nonlinear Δϕ binning to optimize information content determines LUT address space, I. K. Furić, CMS Muon Trigger Phase 1 further correction Upgrades algorithms Best Possible Jun 24, 2011 23

HLT study: a closer look Study by B. Scurlock et al hit position from raw half-strip coordinate after chamber specific corrections full offline hit position precision, no stub direction information in HLT fit • initial study indicates final resolution improvement comes from full precision hit information I. K. Furić, CMS Muon Trigger Phase 1 Upgrades Jun 24, 2011 24

Bit content studies Study by B. Scurlock et al 10 Ge. V/c muon 20 Ge. V/c muon • initial studies indicate we can “pack” information better into LUTs and improve core resolution • real potential: implement in current CSCTF ? I. K. Furić, CMS Muon Trigger Phase 1 Upgrades Jun 24, 2011 25

• brief overview of CSCTF system and experience Conclusions • reasonably robust and very flexible system • we have started thinking about importing MPGD information, not technically impossible • redundancy: fortify • regions around cracks (η~1. 5 -1. 6) • regions with key position information (ME 1/1) • p assignment: • currently working on reaching best T • performance with information we have in hand, LUT stage post-processing is where full precision is GEMs for CMS High Eta Jun 24, 2011 I. K. Furić, CSCTF + MPGD 26