Presentation is loading. Please wait.

Presentation is loading. Please wait.

Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Data based method for background subtraction:

Published bySarah Robertson Modified over 8 years ago

Similar presentations

Presentation on theme: "Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Data based method for background subtraction:"— Presentation transcript:

1 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Data based method for background subtraction: Z →μ + μ - Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Laboratori Nazionali di Frascati, Università di Roma La Sapienza, INFN

2 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Outline  Motivation.  Example of application: bb Z   +  -  Method proposed  Software & Generators Simulation, Reconstruction, Analysis.  Sample  Conclusion and future development

3 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN.  Les Houches Guidebook hep-ph/040345 MonteCarlo Cojest Isajet Ariadne Herwig Sherpa Pythia Jetset

4 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Shower MonteCarlo

5 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Motivation  It is then extremely important to rely on alternative method to MonteCarlo, as much we can  We propose a method based on a different data sample of experimental data  Only hypothesis: lepton universality.  Example of application: bb Z   +  - (most copious background of bb h 0 /A   +  - studies (14/12/2005) S.G. presentation, ATLAS-PHYS-2003-015, June 2003.)

6 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Signal & background  h 0 bb →    + bb  ~ 0.2 - 0.01 pb (even lower)  ~ 22.8 pb  Zbb →  -  + bb  (Pythia 6.226)AcerMC (v.2.3) interfaced with Pythia 6.2 (hep/ph0405247).

7 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Background Subtraction Method  Experimental method proposed based on Z→     and Z→ e + e -  Relying on experimental data  Br( h 0 → e + e - ) neglegible  Different Inner Bremsstrahlung Precise Knowledge of background is crucial

8 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Z production

9 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Software Release & Sample  Generation Athena 9.0.4 - Pythia (v.6.226) - Acer (v. 2.3)  Simulation, Digitalization, Reconstruction Athena 10.0.1  Analysis based on CBNT (root –ntuples).  Final study in scenario ~ 600000 events  In this presentation L int ~ 20 fb -1 ~ 400000 events

10 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Study performed  Different Inner Bremsstrahlung Zbb →  -  + bb (  ) N  ~ 0.086 N ev =464522 Zbb → e - e + bb (  ) N  ~ 0.157 N ev =442828  Different Detector Response  The most significative variable of bb h 0 /A   +  - analysis has be chosen M inv as test.  NB. The combination of a same flavor lepton originating from b and one of Z are included inevitably in the plots

11 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Bremsstrahlung Photons N  MC ~ 0.157 N  MC ~ 0.086 Zbb →    + bb Zbb → e  e + bb e

12 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Bremsstrahlung Photons Zbb → e  e + bb Zbb →    + bb

13 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Generator level: Zbb →  -  + bb Minv(  +  - ) Minv(  +  - ) 

14 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Generator level: Zbb →  -  + bb Only events with a  of Bremsstrahlung Minv(  +  - )Minv(  +  - ) 

15 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Generator level: Zbb →  -  + bb

16 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Generator level: Zbb → e - e + bb Minv(e + e - ) Minv(e + e - ) 

17 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Generator level: Zbb → e - e + bb Minv(e + e - ) Minv(e + e - )  Only events with a  of Bremsstrahlung

18 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Generator level: Zbb → e - e + bb

19 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Generator level Bremsstrahlung events

20 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Generator level

21 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Generator level

22 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Leptons muons electrons

23 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Photons: Zbb →  -  + bb Bremsstrahlung photons All photons P T vs. Distance between  and  watch the different scale ! Subsample(~25000 ev)

24 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Photons: Zbb →  -  + bb Distance between  and  watch the different scale !  R ~ 0.15 All photonsBremsstrahlung photons

25 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Photons: Zbb → e - e + bb P T vs. Distance between  and e watch the different scale ! Subsample(~25000 ev) All photons Bremsstrahlung photons 5x5 cluster in ATLAS

26 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Photons: Zbb → e - e + bb Distance between  and e All photons Bremsstrahlung photons watch the different scale !  R ~ 0.25

27 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Photons  If the photon is emitted close to electron, only one cluster is reconstructed and the combined 4-momentum is measured. For the  is effectively absorbed in the same cluster of the electron.  corresponds to a 5x5 cluster in ATLAS. The energy of electron is measured in e.m. calorimeter,  and  are measured in tracker.  Photons, inside cone  R, are taken in account summing their 4-momentum to the 4-momentum of the nearest lepton.  Photons reconstructed are e.m. clusters without track associated (  0.025,  =0.05 ) and P T >5GeV, |  | >2.5.

28 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. All Photons: Zbb →  -  + bb Zbb →     bb P T  > 5 GeV |  | >2.7 recontructed  Zbb → e - e + bb

29 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Reconstruction  Muons: combined reconstruction (inner detector + spectrometer), P T >10 GeV, |  | >2.5.  Electrons: energy measured in calorimeter,(  ) measured from tracker, P T >10 GeV, |  | >2.5.  Photons: e.m. cluster without track associated :  0.025,  =0.05, P T > 5 GeV, |  | >2.5.  Brem photons: >2 leptons reconstructed +   reconstructed in a cone around lepton direction <  R.  Electrons sample only one cluster is reconstructed.  Muon sample:  track near photon cluster, misidentification. The number events reconstructed with  brem identified is at percent level.

30 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Reconstruction: Zbb →  -  + bb Minv(  +  - )  Minv(  +  - )

31 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Reconstruction: Zbb →  -  + bb Minv(  +  - )  Minv(  +  - ) Only events with a  of Bremsstrahlung

32 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Reconstruction: Zbb → e - e + bb Minv(e + e - )  Minv(e + e - )

33 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Reconstruction: Zbb → e - e + bb Minv(e + e - )  Minv(e + e - ) Only events with a  of Bremsstrahlung

34 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Reconstruction Only events with a  of Bremsstrahlung

35 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Reconstruction The number  bremsstrahlung reconstructed separatly in muons events is higher than electron events, where are mostly absorbed in the electron cluster

36 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Generation-reconstruction

37 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Generation-reconstruction

38 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Conclusions  A study for an experimental method of background subtraction is developed based on fully simulated samples, L int ~ 20 fb -1 of: bb Z   +  - and bb Z   e+ e - comparing:  the Bremsstrahlung of the two samples.  the ATLAS detector response.  The study is preliminary and needs careful tuning on data collected.   R is an extremely important parameter, that should be carefully tuned.

39 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Conclusions  In the region M inv 98 -135 GeV the ratio is reasonably stable and the effect of Bremsstrahlung is negligible with respect to detector response  The same method can be applied to H→  and in general to all decays where the electron decay is negligible in the signal.  The method relies on lepton universality and needs a good knowledge of detector response for different leptons  The method doesn’t need an implementation on MC of higher order corrections Acknowledgements: Borut Kersevan, Dirk Zerwas,Donatella Cavalli

40 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Riserve  Riserve

41 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN.  Matching track narrow  0.025  =0.05  Isolation broad   0.05  =0.10  R =0.07 size of cluster 5x 5  = 0.025  =0.05

42 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN.

43 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN.

Download ppt "Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 18 April 2006,CERN. Data based method for background subtraction:"

Similar presentations

Transverse momentum of Z bosons in Zee and Zmm decays Daniel Beecher 12 December 2005.

Transverse momentum of Z bosons in Zee and Zmm decays Daniel Beecher 12 December 2005.
Gennaro Corcella 1, Simonetta Gentile 2 1. Laboratori Nazionali di Frascati, INFN 2. Università di Roma, La Sapienza, INFN Phenomenology of new neutral.

Gennaro Corcella 1, Simonetta Gentile 2 1. Laboratori Nazionali di Frascati, INFN 2. Università di Roma, La Sapienza, INFN Phenomenology of new neutral.
H  4l in Full Simulation preliminary results 2 A. Khodinov * and K. Assamagan ** * State University of New York at Stony Brook ** Brookhaven National.

H  4l in Full Simulation preliminary results 2 A. Khodinov * and K. Assamagan ** * State University of New York at Stony Brook ** Brookhaven National.
Implementation of e-ID based on BDT in Athena EgammaRec Hai-Jun Yang University of Michigan, Ann Arbor (with T. Dai, X. Li, A. Wilson, B. Zhou) US-ATLAS.

Implementation of e-ID based on BDT in Athena EgammaRec Hai-Jun Yang University of Michigan, Ann Arbor (with T. Dai, X. Li, A. Wilson, B. Zhou) US-ATLAS.
Possible Higgs searches at LHCb A preliminary study investigating the feasibility of finding the SM Higgs at LHCb Jonathan Anderson (UCD)

Possible Higgs searches at LHCb A preliminary study investigating the feasibility of finding the SM Higgs at LHCb Jonathan Anderson (UCD)
1 N. Davidson E/p single hadron energy scale check with minimum bias events Jet Note 8 Meeting 15 th May 2007.

1 N. Davidson E/p single hadron energy scale check with minimum bias events Jet Note 8 Meeting 15 th May 2007.
DPF-2006 1 Victor Pavlunin on behalf of the CLEO Collaboration DPF-2006 Results from four CLEO Y (5S) analyses:  Exclusive B s and B Reconstruction at.

DPF Victor Pavlunin on behalf of the CLEO Collaboration DPF-2006 Results from four CLEO Y (5S) analyses:  Exclusive B s and B Reconstruction at.
Sept 30 th 2004Iacopo Vivarelli – INFN Pisa FTK meeting Z  bb measurement in ATLAS Iacopo Vivarelli, Alberto Annovi Scuola Normale Superiore,University.

Sept 30 th 2004Iacopo Vivarelli – INFN Pisa FTK meeting Z  bb measurement in ATLAS Iacopo Vivarelli, Alberto Annovi Scuola Normale Superiore,University.
Status of  b Scan Jianchun Wang Syracuse University Representing L b scanners CLEO Meeting 05/11/02.

Status of  b Scan Jianchun Wang Syracuse University Representing L b scanners CLEO Meeting 05/11/02.
1 W’  tb  lnubb: the first read. 2 introduction sample: W’  tb  lnubb generator: PYTHIA number of events: 5000 will only use events in the good run.

1 W’  tb  lnubb: the first read. 2 introduction sample: W’  tb  lnubb generator: PYTHIA number of events: 5000 will only use events in the good run.
1 introduction sample: W’  tb  Wbb  eνbb/μνbb generator: PYTHIA five samples with W’ mass: 300GeV, 500GeV, 1000GeV, 1500GeV, 2000GeV number of events.

1 introduction sample: W’  tb  Wbb  eνbb/μνbb generator: PYTHIA five samples with W’ mass: 300GeV, 500GeV, 1000GeV, 1500GeV, 2000GeV number of events.
1 Hadronic In-Situ Calibration of the ATLAS Detector N. Davidson The University of Melbourne.

1 Hadronic In-Situ Calibration of the ATLAS Detector N. Davidson The University of Melbourne.
WW  e ν 14 April 2007 APS April Meeting WW/WZ production in electron-neutrino plus dijet final state at CDFAPS April Meeting 14-17 April 2007 Jacksonville,

WW  e ν 14 April 2007 APS April Meeting WW/WZ production in electron-neutrino plus dijet final state at CDFAPS April Meeting April 2007 Jacksonville,
1 A Feasibility Study for a Strange Sea Asymmetry Analysis at ATLAS: update II Laura Gilbert and Jeff Tseng 13/12/07.

1 A Feasibility Study for a Strange Sea Asymmetry Analysis at ATLAS: update II Laura Gilbert and Jeff Tseng 13/12/07.
In order to acquire the full physics potential of the LHC, the ATLAS electromagnetic calorimeter must be able to efficiently identify photons and electrons.

In order to acquire the full physics potential of the LHC, the ATLAS electromagnetic calorimeter must be able to efficiently identify photons and electrons.
Jake Anderson, on behalf of CMS Fermilab Semi-leptonic VW production at CMS.

Jake Anderson, on behalf of CMS Fermilab Semi-leptonic VW production at CMS.
T-CHANNEL MODELING UNCERTAINTIES AND FURTHER QUESTIONS TO TH AND NEW FIDUCIAL MEASUREMENTS Julien Donini, Jose E. Garcia, Dominic Hirschbuehl, Luca Lista,

T-CHANNEL MODELING UNCERTAINTIES AND FURTHER QUESTIONS TO TH AND NEW FIDUCIAL MEASUREMENTS Julien Donini, Jose E. Garcia, Dominic Hirschbuehl, Luca Lista,
22. April 2004, New Phenomena MeetingChristian Autermann - Resonant Slepton Production1 Overview R-parity violating Supersymmetry Cross section and Run.

22. April 2004, New Phenomena MeetingChristian Autermann - Resonant Slepton Production1 Overview R-parity violating Supersymmetry Cross section and Run.
Quark Compositeness Study and Progress Satyaki Bhattacharya, Sushil S. Chauhan, Brajesh C. Choudhary & Debajyoti Choudhury Department of Physics & Astrophysics.

Quark Compositeness Study and Progress Satyaki Bhattacharya, Sushil S. Chauhan, Brajesh C. Choudhary & Debajyoti Choudhury Department of Physics & Astrophysics.
W properties AT CDF J. E. Garcia INFN Pisa. Outline Corfu Summer Institute Corfu Summer Institute September 10 th 2 1.CDF detector 2.W cross section measurements.

W properties AT CDF J. E. Garcia INFN Pisa. Outline Corfu Summer Institute Corfu Summer Institute September 10 th 2 1.CDF detector 2.W cross section measurements.

Similar presentations

Ads by Google