In-situ calibration with Zee events

13/12/2007

In-situ calibration with Zee In-situ calibration with Zee eventsevents

Nikola MakovecGroup meeting

Nikola Makovec 2

OutlinOutlinee CSC Note EG-6, section Intercalibration

Motivation Data sample and event selection Description of the method

The fitting method Reference distribution

Method testing Results with misaligned and distorted geometry Conclusion

8 pages

Nikola Makovec 3

MotivatioMotivationnIn situ calibration of the EM calorimeter with

Zee events:

Intercalibration Non-uniformities

Temperature Purity Extra-material in front of the calorimeter

Local constant term ~0.5% (=0.20.4) Goal : 0.7% (TDR) Intercalibrate these regions to a level of 0.4%

Absolute energy scale Physics atlas program : ~0.1% W mass measurement : ~0.02%

LRL CCC

Nikola Makovec 4

Data sample and event Data sample and event selectionselection Data sample :

Trig1_misal1_csc11_V1.005144.PythiaZee.recon.NTUP.v12000601 Studies at the generator level

Trig1_misal1_csc11_V1.005144.PythiaZee.recon.NTUP.v13003002 Used after simulation and reconstruction

Event selection at least electrons The 2 leading should satisfy

pT>20GeV ||<2.4 IsEM(Medium)=true

80<Mee<100

Nikola Makovec 5

Description of the method (1)Description of the method (1)

Notation:

The fitting method: 2 step : Measurement

Minimising the following log-likelihood :

generalized least squared method is applied leading to an analytical solution.

Nikola Makovec 6

Description of the method (2)Description of the method (2)

The reference distribution

Nikola Makovec 7

Method testing (1)Method testing (1)

Done at the generator level Injected bias drawn from a Gaussian(,) Gaussian(0,2%)

Nikola Makovec 8

Method testing (2)Method testing (2)

Gaussian(,2%)

Nikola Makovec 9

Method testing (3)Method testing (3)

Expected constant term as a function of the luminosity

Nikola Makovec 10

Results with misaligned and distorted geometry (1)Results with misaligned and distorted geometry (1)

Gaussian(0,0%)

Nikola Makovec 11

Results with misaligned and distorted geometry (2)Results with misaligned and distorted geometry (2)

Nikola Makovec 12

Results with misaligned and distorted geometry (3)Results with misaligned and distorted geometry (3)

Gaussian(0,2%)

Nikola Makovec 13

Results with misaligned and distorted geometry (4)Results with misaligned and distorted geometry (4)

Nikola Makovec 14

ConclusioConclusionn With~200pb-1:

Constant term ~ 0.7% Absolute scale known with a precision of few

percent

Care of extrapolation to other energy spectrum (linearity?)

Amount of material in front of the detector : E/p Conversion Energy flow

Nikola Makovec 15

To do listTo do list

Corrections de la note : Fond? Forme Style et orthographe

Si vous avez un peu de temps: /exp/atlas/makovec/Notes/CSC-EG-6.pdf

Photo non contractuelle

Pot pour mon retour au LAL :Vendredi 21 décembre à

11h30 Salle 129