1. CMS Upgrade Project Office Meeting
TPSWG Interim Report
Oliver Buchmueller
Imperial College
Wesley H. Smith
U. Wisconsin
On behalf of TPSWG
CMS Upgrade Project Office Meeting
February 1, 2013
Outline:
Members
Report Contents
Goals for next report

2. TPSWG Members
Substantial thanks to members for contributions: Subsystem representatives: Duccio Abbaneo & Andrea Venturi (Tracking & tracking Triggers), Cristina Fernandez Bedoya (Muon Systems), David Barney and Jose Carlos da Silva (ECAL), Paolo Rumerio (HCAL), Frans Meiers (DAQ), Ian Fisk (Computing), Chris Hill (Physics), Emmanuelle Perez and Anders Ryd, (co-chairs of the Track Trigger Integration Subgroup) Trigger Experts: Pierluigi Zotto (DT), Ivan Furic (CSC), Karol Bunkowski (RPC), Claudia Wulz (GT/GMT), Sridhara Dasu and Dave Newbold (Calorimeter Triggers: RCT & GCT), Ex Officio: CMS Electronics Coordinator: Magnus Hansen, L1 Trigger PM: Darin Acosta, L1 Trigger Upgrade Coordinator: Alex Tapper, Trigger Coordinator: Roberto Carlin, Upgrade Coordinators: Didier Contardo & Jeff Spalding.

3. Trigger Upgrade Strategy - I
A key goal of the CMS HL-LHC upgrade program will be to maintain the physics acceptances of the key leptonic as well as hadronic trigger objects such that the overall physics acceptances, especially for low-mass scale process like Higgs production, can be kept similar to the 2012 ones In order to accomplish this physics goal, the work of the TPS focuses on two key components. The first one is the addition of a L1 tracking trigger for identification of tracks associated with calorimeter and muon trigger objects at L1. The second focus point is to study the option of a significant increase of L1 rate, L1 latency and HLT output rate.

4. Trigger Upgrade Strategy - II
Although addition of track trigger at L1 will help to maintain rate requirements for leptonic trigger objects such as muons, electrons and possibly also taus at reasonable levels, only limited improvement is expected for:
photon triggers (except for track isolation)
hadronic trigger objects (except for requiring jets to have tracks pointing at the vertex).
To continue triggering on photon & important hadronic objects during HL-LHC operation, it may be important to increase L1 acceptance rate substantially beyond constraint of 150 kHz.
Significant increase of latency beyond 6.4 μs would provide more time for:
Tracking trigger calculations (including pixel tracking)
Combination of calorimeter and muon trigger information with that of the tracking trigger
additional flexibility which in turn could be used to facilitate L1 decisions and reduce rate required on key trigger objects.

5. Tracking Trigger Uses
Validate a calorimeter or muon trigger object, e.g. discriminating electrons from hadronic (π0) backgrounds in jets
Addition of precise track hits to improve precision on the pT measurement, sharpening thresholds in the muon trigger
Degree of isolation of e, γ, μ or τ candidate
Primary z-vertex location within 30 cm luminous region derived from projecting tracks found in trigger layers,
providing discrimination against pileup events in multiple object triggers, e.g. in lepton plus jet triggers.

6. Track Trigger Integration Subgroup
Formed in Fall 2012, meets weekly on Mondays
Developing plans so study how the track trigger can augment the L1 muon and calorimeter trigger in the identification of muons, electrons, taus, and jets.
Working on tools and MC samples for these studies
Volunteers are very welcome (and needed)!

7. TPSWG Subsystem Survey
Option of L1 Trigger latency of 20 μsec, rate of 1 MHz & HLT output rate of 10 kHz is feasible for all subsystems (pending rebuild of EB FE electronics & replacement of CSC FE electronics), DAQ & Computing, but has significant cost (funds, personnel, time) & is under serious consideration.
Intermediate scenario of 0.5 MHz also considered
Details are in the report for all subsystems.
Some further refined details for next report.

8. TPSWG Architecture Proposal
Propose to ask all development for Phase 2 be compatible with L1 Trigger latency of 20 μsec, rate of 1 MHz & HLT output rate of 10 kHz.
Propose to ask all subdetectors to present a plan to operate with L1 Trigger latency of 20 μsec, rate of 1 MHz & HLT output rate of 10 kHz
Cost & schedule of any modifications/updates
Performance (e.g. trigger & reconstruction efficiency) of subdetector system, including any modifications/updates, with with L1 Trigger latency of 20 μsec, rate of 1 MHz (or 500 kHz) & HLT output rate of 10 kHz
Final decision to be taken by end of this year.

9. Next Steps
Study the impact on physics reach of adoption of the proposed new architecture.
Study the gain in acceptance for hadronic channels for a higher L1 rate
Study the gain in track trigger performance by itself and in combination with muon and calorimeter triggers if the latency is increased.
L1 Track Trigger Integration Subgroup will develop performance requirements for the tracking trigger and provide more information on the gain in physics reach from deploying a L1 tracking trigger.
Next report during CMS Upgrade Week, June, 2013.

10. Please send your written comments to me and Oliver by Tuesday. Thanks!
Feedback
Please send your written comments to me and Oliver by Tuesday. Thanks!