1. CC/NC SEPARATION STUDY Andy Blake Cambridge University Friday February 23 rd 2007

2. Introduction Andy Blake, Cambridge UniversityCC/NC Separation, slide 2 Have developed a PID for CC/NC separation PID is calculated using a likelihood technique, and extends the “standard” PID algorithm by incorporating some new PDFs and accounting for their change in shape as a function of energy. Code committed to “MadAbID” class in Mad package. Documentation also available in doc-db #2720. Will outline method and present some results in this talk.

3. PID Variables Andy Blake, Cambridge UniversityCC/NC Separation, slide 3 Variables for CC/NC separation Event Topology Variables. – percentage pulse height in track. – pulse height per track plane. – number of track like planes. – percentage error in track fit. Event Kinematics Variables. – reconstructed y. Event Energy and Charge. – number of track planes. – reconstructed charge. Relative CC/NC Normalization. Test consistency with muon track. Test consistency with CC interaction. Incorporate CC/NC spectral information.

4. PID Definition Andy Blake, Cambridge UniversityCC/NC Separation, slide 4 PID calculated from the product of several 1D and 2D PDFs as follows:

5. PID Variables: (I) Track Topology Andy Blake, Cambridge UniversityCC/NC Separation, slide 5 TRACK-LIKE PLANES vs TRACK PLANES

6. PID Variables: (I) Track Topology Andy Blake, Cambridge UniversityCC/NC Separation, slide 6 TRACK PH / TRACK PLANES vs TRACK PLANES

7. PID Variables: (I) Track Topology Andy Blake, Cambridge UniversityCC/NC Separation, slide 7 TRACK PH / EVENT PH vs TRACK PLANES

8. PID Variables: (I) Track Topology Andy Blake, Cambridge UniversityCC/NC Separation, slide 8 TRACK FIT ERROR vs TRACK PLANES

9. PID Variables: (II) Event Kinematics Andy Blake, Cambridge UniversityCC/NC Separation, slide 9 RECO Y vs RECO E

10. PID Variables: (III) CC/NC Spectrum Andy Blake, Cambridge UniversityCC/NC Separation, slide 10 TRACK PLANES RECONSTRUCTED CHARGE CC/NC NORMALIZATION

11. PID Study Andy Blake, Cambridge UniversityCC/NC Separation, slide 11 Cedar MC Ntuples. – Far Detector ( generate PDFs using 8.7e22 PoTs calculate PIDs using 2.9e22 PoTs). – Near Detector ( generate PDFs using 8.5e18 PoTs calculate PIDs using 2.5e18 PoTs ). Event Selection. – reconstructed track. – successful track fit. – contained track vertex. Construction of PDFs. – PDFs constructed assuming no oscillations. – 2D PDFs normalized to remove any spectral information. (i.e. divide out the shape of the energy spectrum). – as a final step, try pre-selecting events with P CC =1. (i.e. create second set of PDFs for events with P CC <1).

12. PID Results (Far Detector) Andy Blake, Cambridge UniversityCC/NC Separation, slide 12

13. Purity vs Efficiency (Far Detector) Andy Blake, Cambridge UniversityCC/NC Separation, slide 13 Standard PID: track PH/ event PH. track PH/ track planes. track planes. Incorporate: track-like planes. track fit error. track charge. reconstructed Y. (replace trk.ph/evt.ph). pre-selection. N.B : maximum values of purity*efficiency indicated by stars

14. Purity vs Efficiency (Far Detector) Andy Blake, Cambridge UniversityCC/NC Separation, slide 14 Standard PID cut approximately here!

15. PID Results (Near Detector) Andy Blake, Cambridge UniversityCC/NC Separation, slide 15

16. PID Results (Low Energies) Andy Blake, Cambridge UniversityCC/NC Separation, slide 16 E < 3 GeV 6 < E < 9 GeV 3 < E < 6 GeV E > 9 GeV

17. Summary Andy Blake, Cambridge UniversityCC/NC Separation, slide 17 Incorporation of new variables into PID calculation improves purity and efficiency of CC/NC separation in both detectors over all energies. This will hopefully improve the sensitivity of the oscillation analysis! Possible improvements to this method: – Separate fully and partially contained events. – Separate neutrinos and anti-neutrinos. – Incorporate other topology variables (e.g. pulse height profile of event). – Incorporate another kinematic variable (e.g. x distribution).