Ageing study with electron

Zone definition

9

8

521

7

3

9 zones defined . Statistics : Minimum biais sample : 20K electron /1 hour run Bhadron sample : 250k electron / 1 hour run Check on 1 run no difference

9 zone defined 4 6

Data sample

• 2010 & 2011 data sample up to Mid August 2011– 450 pb received– Analysis not yet systematic on all fill

• E/p , Cluster/pr , ratio -> PS ageing • 9 zones

– 2011: correct by Dasha coefficients.

Electron selection

• Associate 2 tracks

• Keep for each track the Minmass

• Select electron using RichDllE and loose electron id.

• Keep the associated particle

• In N-tuple apply :– Richelectron id > 0– Hadron isolation

Fit results

• Statistic– 2 million candidates– Bhadron stream

• Fit precision – Zone 1-7

1-2 per mil

- Zone 8_9

1 to 4 per mil

Zone 3 4 5

Coefficient produced

• Re-evalute EoP using Dasha fine coefficient beginning of June

• The first week of June is the reference (fill1852)

• Evaluate in range of 40pb-1 the ageing to correct for for each of the 8 zone

• Produce coefficients /cell – C_dashaJune * EoP[June]/EoP[current-fill]– Period 40pb-1

Effect of dasha coefficients

Fit results -Effect of dasha coeff outer zone-- Normalisation point :

-Fill 1852

Zone 5 : +6%Zone 6: +3.5%Zone 8-9 : +2%

Due to ageing Zone 5 : +5%Zone 6 : 4%Zone 8 : 2%

Effect of Dasha coefficient

All sigmas improve with Dasha oefficients

Dasha Coefficient /zone

Inner

middle

Outer

Large Tails

Normalize / fill1852

Same trend for all

Stronger close to the beam

Trend to apply

Zone 1 : 9%Zone 2 : 3.8%

Zone 3 : 5%Zone 4: 4.2%Zone 7: 3%

Averaged ageing 700pb-1 :8.5% - ~0.5% /40pb-1

Trend to apply

Zone 5 :9.5%Zone 6 : 7%Zone 8-9 :3%

(Outer)

PS trend

EoP

Cluster/P

RatioNo effect bigger than 2%Due to PS

More study /zone

Dasha zone

Comparison to dasha coefficient

ZoneI1Zone 1

ZoneI2Zone 1

Dasha Trend spread

Trend spread ~ 2.5% Alll statistics used ?

Dasha trend medium

Outer part

With the present stat used Spred of 4%

Correcting before fine calibration will introduce an unphysical effect and therefore the time needed converge will increse

Using ALL Fmdst statistics and using only fill above 3pb-1 should solve this effect

Plans

• Data have been processed up to the technical stop and correction file will be produced this week

• More statistics produced for the early runs • The present calibration is a consequence of last

year correction with LED• Large sample of electron being used to

understand the EoP tails ( Victor) , PID efficiencies

• Understand calibration of electrons

Ageing effect in all zones