DD

W/Z Muon Selection

For Winter Conferences

Tom DiehlFNAL

@ Saclay 12/2001

“Tight” and “Loose” Muon selection for the WZ group

“Muon Quality”

Specification and Description of “Tight” “Loose” “Astub”

What we have to do for these to be complete What I know What I don’t know?

W/Z -> muons selection criteria Ideas I have or have heard that I

liked

Muon Quality “Tight”

Specification for “Tight” Identify all “typical” muons using muon-

only information All muons available in one chunk & All

information about them available in that chunk or from pointers there.

Uses the pieces of the muon detector that are also used in the L1 trigger

It’s used now in Reco for “Muon-Corrected MET”

(Quality=4) WZ_Reco for streaming from FARM La Macchina for selecting Muon_L3

Muon Quality “Tight”

Definition of “Tight” MuonID Use MuonID chunk NS!hits(A-layer)>0 (1 @ L1) NWhits(A-layer)>1 (3-4 maximum) NS!hits(BC-layer)>0 (1 @ L1) NWhits(BC-layer)>2 (2*3-4 typical, 2-4 not

unlikely [holes] ) Chi^2>0 (fit converged)

I believe it satisfies non-technical part of the specifications

“Tight” definition is looser than in Run 1 - we can afford that

The inner tracker will be a major contributor to muon ID, not only making the pT determination but also providing remaining background rejection

Specification for “Loose”

Identify all muons that can be found with the muon detector

not intended to be a “muon-detector-unbiased” sample

keep in mind holes in the detector coverage and typical electronics failures

Efficiency of “Loose” should be reliable with MC calculation

“Loose” muons should provide a sample with which to measure the efficiency of each component of “Tight”

Same technical specifications as for “Tight” i.e.- one chuck - all parameters available there or via pointers (we are stuck with tuples through winter conferences)

Muon Quality “Loose”

Definition of “Tight” muon MuonID chunk

1a) NS!hits(A-layer)>0 (1 @ L1) 1b) NWhits(A-layer)>1 (3-4 maximum) 3) NS!hits(BC-layer)>0 (1 @ L1) 4) NWhits(BC-layer)>2 (2*3-4 typical,

2-4 not unlikely [holes] ) 5) Chi^2>0 (fit converged)

A “Loose” muon can fail one of the above criteria except 1a) and 1b) count only as one possible failure*

*Because A-layer scint. and drift chamber holes are coincident

Drift Detectors

Scintillation Counters

Muon Quality “Astubs”

Specification for Astubs primary: Identify muons that don’t

penetrate the toroid magnets 1.1 < pT(GeV/c) < 3 or 4 in central 1.1 < p (GeV/c) < 3 or 4 in forward

secondary: Identify muons that miss all of BC

Definition (hardly even preliminary) “Astub” is S!Hits&WHits(A-layer)>1 For L3, it’s probably got overlap with

“Loose” and “Tight” Warning: There’s lots of these because

of background

Problems with Quality Definitions

In p10.13.00 all “Tight” are available in MuonID bank as nseg = +3 or -3 (and some of the “Loose” are +-3 as well) but … Not ALL “Loose” are available in MuonID chunk.

“Loose” must include BC tracks with a pT calculated from the vertex (nseg=-2) as well as those that have a gtrk match (nseg=+2)

Muon Duplication One real muon can occur in the MuonID

bankchunk up to three (six*) times if it’s in a dense region of central tracks, in a jet, perhaps.

What else?

That I know of 15/Dec/2001

Muon Isolation Definition

Most Physics Groups have agreed to use R(mu-jets[0.5])>0.5 until someone demonstrates something better.

We haven’t taken time to reoptimize this since Run I Note that central muon phi resolution is

pretty bad (unless nseg is positive) Note that forward muon phi resolution is

pretty bad (unless pixels are used in segment)

W/Z to Muons Selection

W’s: “Tight Muon” plus trackmatch Z’s: Probably “Tight” * “Tight”

“Tight” * “Loose” and at least one trackmatch.

Plus sensible kinematic requirements

Some Good Ideas

“Tight” scintillator timing L1 trigger gate is 24 ns wide in central A-Layer. Efficiency

would remain 99%+ if this was tightened to 18ns in L1 or L3 and probably could be tightened more Offline given some careful studies

Similar comment for all the rest of the scintillator Count Decks instead of Hits in performing ID (Dave)

PDT’s & MDT’s have 3 or 4 decks This is obviously correct.

Use the Inner Trackers !!!!!!!!!

Some More Good Ideas

Locate the beam scraping source in the North Tunnel - “a hot topic”

More Shielding in A-Layer - part of upgrade for Run 2b

Muon unbiased muon I can imagine how we might do this and it’s

something to think about six months down the road …

Summary

I’ve discussed “Tight” and “Loose” muon definitions and their specifications

W/Z group is applying a “Tight” muon definition and has a working definition for “Loose”

We plan to select postshutdown events based on these definitions with the addition of Inner Tracker and sensible kinematic information.

Good ideas that I have heard

Trailer

MY Talk Ends Prior to Here

Single Muon Trigger Rates L=4.7e30 mu1cmsc_fz = 46 *(64/108)

=>5.8 hz/10^30 (not including octants 5 & 6)

mu1pix_fz = 60 hz =>12.8 hz/10^30

Readout Bandwidth seems to be 30 hz so single muons are getting prescaled heavily

W/Z to Muons

Tightergates

Efficiency Calculation

isolationTrackTriggerTightLooseefficiency ****

Efficiency For W’s

22

22

*

**]2[*

isolationTrack

TriggerTightTightTwoLooseefficiency Efficiency For Z’s

Partly from Monte Carlo. Monte Carlo calculates acceptance & kinematic

selection Monte Carlo doesn’t model the detector performance

Partly from Data Use Data whenever possible See above in reverse for Data

Muon Changes I

Reported by Frederic last time for p10.11.00 muo_trackreco

addition of quality word (quality = 4 corresponds to “tight”)

muon_id addition of MuonQualityInfo int Nhit =

NWA+10*NWBC+1000*NSA+10000*NSBC

method muoTrackIndex returns the local track index for |nseg|=3 else -1

method segIndex returns segment index for nseg=1&2 else -1

method TightMuoTrack returns “T” if “tight” muon (used by METcalmu)

Muon Changes II

Migrating muon selection (e.g. “tight” & “loose”) to Muon_ID Muon_ID

nseg = -3: criteria changed from NWA>2 & NWBC>3 & 0<Chi2<1000 NWA>0 & NWBC>1 & -inf<Chi2<inf to match nseg=+3 (note it takes 2 hits to make a segment)

Failed to make an nseg= -2 in muon_id because there’s no BC-only tracks in muo_trackreco (Frederic is working on this)

Muon_ID Track-Matching nseg = 3: trackmatch in Central w/

PT(gtrak)>3.0 GeV/c (was 1.5 GeV/c) note it’s still 1.5 GeV/c in Forward note it’s 3.0 GeV for BC-only (nseg=2) note it’s 1.5 GeV/c for Astubs

Criteria dZ(A-L.cm) dPhi dEtaSMT (100/pt)+10 0.5 0.4 Global same same sameCFT none same none(all now RCP controlled) (was 4) Still, because in Muon_ID we match on A &

BC segments, it’s possible to have an A-stub or BC-seg with a trackmatch in common with an ABC muon?

Track-matching is done with a CH loop (Pt-ordered) priority-ordered by muo_trks, BC-segs, Astub-segs

Muon Changes II continued

Muon L3 Filter

What criteria are we going to have available to identify muons in L3?

We separated “muon object” from “object relational” criteria and concentrate on the “muon object” to begin with.

In step with the offline selection. Providing muons well-matched in selection

criteria Providing means to measure efficiency

Attempting to anticipate the requirements of triggers

DD

Muon Selection Criteria

Muon_L3(key,Nmu,eta,Region, Quality,PtLocal,TrackMatch, PtTrackmatch,CalMatch) “key” is a marker for relational tools Nmu is the required count eta cut (e.g. |eta(muon)|<eta) Region (e.g. forward/central) Quality (“Tight” ,“Loose”, & “Astub”) based on muon criteria

more coming up PtLocal (Pt of the muon local track) Trackmatch criteria more coming up PtTrackmatch (Pt of inner tracker) CalMatch criteria not much yet

First Try:

Track Match Criteria

Matching with Central Tracks is important for muons, especially since we anticipate (and see) relatively pure muon triggers.

Capability in hand includes global trackmatch via best spatial criteria. Paul is expanding the tracking

detector options and is considering selecting the track

with a Pt-ordered spatial criteria.