A preliminary estimate of the beam n e ’s from antineutrinos

1. A preliminary estimate of the beam ne’s from antineutrinos David Jaffe, Pedro Ochoa December 7th 2006

2. Data and MC used • Data used: • Horn-off: LE-10, Birch, 2.77x1018 POT (couple of days Feb-2006) • Horn-on: LE-10, Birch, 8.15x1019 POT (Oct 2005 -Jan 2006) • MC used: • Horn-off: LE010000, Carrot, 1.32x1019 POT • Horn-on: LE010185, Carrot, 4.17x1019 POT

3. Preliminary results of n from m+: Expected to be highly negative by construction Should be real nubars from m+ if data/MC from horn-off is trust- worthy in this region Should be ~0 by construction Should be real nubars from m+ • Note: talked with Zarko about using new neutrino-antineutrino combined fit in modified energy range for nubars. In progress. • Details can be found in backup slides and in minos-docs 2421 and 2218).

4. Main systematics for n from m+ are: • n from m+ selection efficiency: no systematic yet. • In addition, uncertainties when going from n to ne: For the atmospheric paper, Hugh G. estimated 13.5 % uncertainty in s(nm)/s(nm) (see minos-doc-1424). Should be almost identical for s(nm)/s(ne) Systematics • Error in fit: no current estimate for SKZP “a la Boston” with antineutrinos. Will have one with new fit. • How accurate is the Horn-off disagreement between data and MC to scale the Horn-on MC? No systematic yet • Purity of antineutrino sample: see minos-doc-2205 • Cross-section shape uncertainty: see talk tomorrow • s(nm)/s(ne): • Reconstruction efficiencies for n and ne’s: small effect (?) • Deconvolution to extract ne spectrum: no systematic yet • ND-FD extrapolation: no systematic yet

5. ne ne from m+ - Selection efficiency for n from m+ is 31.38 % ± 1.9% (stat) - Ratio of ne’s from m+ to n’s from m+ is 2.97±0.14(stat) ±0.40(syst) - Ratio of ne’s from m+ in detector to those in fiducial volume is 5.04±0.14(stat) Doing the numbers Assume we are dominated by statistics • n from m+: Combination of scaling methods 1,2 and 4 gives: 5235.7 ± 629.6(stat) ± 818.5 (syst) • Necessary parameters from MC (all below 30 GeV): • With Stan’s method, at 1x1019 POT we get: (this is reconstructed ne’s from m+, not all ne’s that go through the detector)

6. Backup

7. Reweighting nubars from m+ n from m+, raw MC n from m+, reweighted MC

8. Scaling method 1

9. Scaling method 2

10. Scaling method 3

11. Scaling method 3-alt (no fit to ratio)

12. Scaling method 4

13. Fit method

14. (Fit method 2 – discredited)

15. (Fit method 3 – discredited)