L3 Muon Trigger at D0L3 Muon Trigger at D0Status ReportStatus Report

Thomas Hebbeker for MThomas Hebbeker for Martin Wegner, RWTH Aachenartin Wegner, RWTH Aachen, April 2002, April 2002

The D0 muon system

Functionality of the L3 muon trigger

Muon efficiencies

Muon rejection

Summary and Outlook

The D0 Muon systemThe D0 Muon system

Central region (||1):

3 layers of drift tubes

1 layer inside, 2 layers outside the toroid

2 layers of scintillation counters

Forward region (1<||<2)

3 layers of Iarocci tubes

3 layers of trigger scintillators

Functionality of the L3 triggerFunctionality of the L3 triggerLinux PC farm, adapted offline reconstruction code, 45 ms per event

M. G.

M.W.

M.W.

Input parametersInput parameters

"Tight"

# of scint. hits in A >0

# of wire hits in A >1

# of scint. hits in BC >0

# of wire hits in BC >2

2 of track >0 (i.e. fit converged)

"Loose"

1 of the "tight" criteria failed

no 2 requirement

"A-stub"

# of scint. hits in A >0

# of wire hits in A >1

Definitions of muon categoriesDefinitions of muon categories

track quality (below)

transverse momentum

detector region

match with central track or calorimeter

A first glimpse: geometrical A first glimpse: geometrical coveragecoverage

On a large scale loose tracks are uniformly distributed in andTracks are missing:

at octant boundaries in forward regionin the bottom octants at transition from WAMUS to FAMUS

Number of loose tracks

Single MC, flat from -2.5 to 2.5, p

t flat from 2.5 to 200

GeVall loose tracks

Efficiencies for single muon MCEfficiencies for single muon MCOverall efficiencies:

50% for "tight."

77% for "loose.“

71% for "a-stubs."

Eff. for tight muons and A-stubs are correlated.

Data: the "Moriond samples"Data: the "Moriond samples"

Sample of 1894 selected Di-Muon events in FAMUS In 84 % of the events at least one a-stub was found by the trigger " 82 % " " " at least two a-stubs were found " 83 % " " " at least one loose muons were found " 81 % " " " at least two loose muons were found " 78 % " " " at least one tight muon was found " 46 % " " " at least two tight muons were found

Rejection factors over L1Rejection factors over L1

Data: special run with L1 trigger “mu1ptxctxx” only 19324 events Without p

t cut the rejection factor is 1.88 for loose

and 4.1 for tight muon tracks

The next stepsThe next steps Fix memory leak.

Event by event comparison of L3 results and offline reconstruction.

Improve efficiency. Problem in unpacker ?

Implement cross-octant segments etc.

Build relational filters for physics.

Summary current statusSummary current status L3 muon trigger works “in principle” Efficiencies too low