Low PT Results with tag-02-25 Ntuples

Lina Galtieri for the Lowpt/W+jets group

LAL, Orsay

Outline

New baseline results for the DF channels

Cutflows, plots

Control Regions plots for Low and All Pt's

SS-CR for Low and All Pt's

OS-SS not shown today

Summary of observations

OS-SS results for DF

Analysis Conditions

Ntuples: tag-02-25

Cross Section file V10

top XS increased. Sherpa is used for Wg*

Code updated with fixes and improvements

baseline with METTrackHWW_CL Cuts

MET>20 (njet=0), MET>10 and Max(MTW2) > 50

W+jets : V8.1 : new lepton PID + LH for the electrons

see Keisuke's talk at Wjets/LowpT meeting, Oct 23.

NF: from all the events

WW: 1.20 (nj=0), 1.o9 (nj=1)

Top: 1.03(nj=0), 0.99 (nj=1)

Z+jets: 0.98(nj=0), 1.04(nj=1)

SSCR: 1.09 (nj=0), 1.10(nj=1)

Low PT tag-02-23 and tag-02-25 NJ=0

Comparison, after the DFll cut, of many steps in the analysis

Lepton selection changes: Tight++ to new PID, to LH added

PID

change

LH

change

The PID change reduced the me background in W+jets

The LH change reduced the overall background by ~5%

Low PT tag-03-23 to 02-25 Njet=1

For Nj=1 after the DFll cut, we see a different pattern

PID

change

LH

added

PID change reduced the W+jets somewhat. The LH affected the WW background. The TrackMET change improves the signal as well as the S/B

Low PT Statistics

It contributes 21.5% of the events and 23.8% of the background in the em channel

It contributes 25.3% of the events and 23.3% of the background in the me channel

Only the stat analysis can tell us what the real contribution is

Low PT Statistics

It contributes 21.5% of the events and 23.8% of the background in the em channel

It contributes 25.3% of the events and 23.3% of the background in the me channel

Only the stat analysis can tell us what the real contribution is

Comments on cutflows and plots

Recent efforts have improved the low pT sample.

Njet=0: reduced the overall background by 12%.

Signal has gone up by 15%. S/B is 3% higher

For Njet=1 we have: background is down by 6.6%.

Signal is up by 22%. S/B is increased by 14%

Most important issue is related to the systematic uncertainties that will enter in the final fit. The W+jets

background is about 30% of the total, but it has the largest systematics. Work on this is still going on (Fake factors..)

Will show a few plots here.

A more complete set will be posted on share point

Look at CR plots first, SS next, SR at the end

Normalized SS Control Region (all PT)

All Pt's

em

em

me

me

em+me

em+me

good Data/MC agreement

SSCR WW-CR njet=0

em still a bit underestimated.

em

em

me

me

Low PT Blinded Signal Region (1)

results

em

em

em

me

me

me

good Data/MC agreement

SS Low PT: MT after Ptll cut

em: still underestimated

me: clear improvement is seen

em

em

me

me

em+me

em+me

Low PT SS-CR: Mll

em

em

me

me

em+me

em+me

good Data/MC agreement

Summary of Observations

Cutflows: low pT contribution is 22-25% of the signal, and 23% contribution to the background

The new electron PID has decreased the em W+jets background by over 20%. However, with the new TrackMet baseline, we increase a bit this background.

SSCR plots of low pT events look good

Opposite sign CR's: data/MC for em and me channel

look good

The em channel background has improved, but still is somewhat underestimated. For the me channel Data/MC agreement has improved, but it is not perfect.

SS CR, i.e. after the DFll <1.8 cut , look good

Backup

2002-04-21T14:25:46

Lina Galtieri