Muon Reco Notes (02/05/2019)

Overall Plan:

How muon reco has been improved due to upgrade.
How they perform muon reco.
How they calibrate using muon reco.

Today:
How are muons reconstructed?
Which detectors do we use?
What do all the components of the detector do?
How does the magnetic field look in the detector?

How are muons reconstruced?

"With great care." - Paddy McCormack 2019

First let's talk about the Muon Spectrometer

There is a gap in eta = 0 due to cabling, etc.

Resistive plate chamber - Two parallel plates with gas inbetween.

Thin gap chamber - similar to RPC.

RPC:
Ionization of gas and collection of charge at plates, you can determine
eta of track.

Cathode Strip:
Use x-y grid of wires to measure position.

Monitor Drift Tube:
Measure the drift of the muons due to magnetic field.


Is it more benificial to add another layer or raise the magnetic field?

Due to the large pT of the muons, it would probably be more benificial to 
increase the magnetic field in order to bend the tracks more. This would 
make the uncertainty on track pT much smaller. This is true for any large pT.

How do muons coming from the J/Psi look compare to muons coming from Z?

Muons from J/Psi are very close together. Muons from Z are usually back to back.

Types of Track Algorithms:

Combined: MS & ID done separately, then combined. Out-In approach used. In-Out done as a check.

Calo-Tagged: Muon in ID used if it corresponds to a track in MS. Used when only one MS layer crossed.

Segmented-Tagged: Track in ID labeled Muon if associated to "min-i" type signature in calo. Optimized for
eta < 0.1.

Extrapolated: No ID hits but originating from IP. Used for  2.5 < eta < 2.7.

Four types of quality cuts: Loose - Medium - Tight - High pT

Medium used for most analyses but loose is helpful for background modeling/calculation.