MINOS 1 Beam e ’s from antineutrinos David Jaffe and Pedro Ochoa September 27 th 2007  Preliminaries  Data & MC  Expected sensitivities  Preliminary results  Outlook − Preliminary Results −

MINOS 2 3) Fit resulting distribution (top right) using shapes from the MC scaled by parameters parHE and parLE: Preliminaries x parLE ( ,K) pHE - ( ,K) LE x parHE pHE - LE +C (simulated) 2) Apply a correction C for from   and   parents C=  pHE -  ) LE (  + ) pHE (  + ) LE  Goal is to measure the antineutrinos from  + decay (brothers of beam e ’s)  Antineutrinos from  + are the most affected when changing the beam configuration. The technique for the measurement is: 1) Scale pHE and LE DATA to same POT and subtract

MINOS 3  Measurement can also be done with pME data (minos-doc 2706)  Systematic error from background uncertainty is practically negligible on    LE  Errors in  + ) LE determination from horn & target systematics are in the order of ~5-10%  Systematic errors associated with hadron production uncertainties are yet to be determined. Some on this at the end.  Systematics were addressed in minos-docs 2909 & In particular: Preliminaries  More details on the method in minos-doc 2783  Statistical error with 1.6x10 19 POT of pHE data was expected to be ~15% (minos-doc 3230)

MINOS 4  Data & MC used:  DATA le010z185i runI: 2.46x10 19 POT  DATA le010z185i runII: 2.21x10 19 POT  DATA le250z200i runII: 1.41x10 19 POT  MC le010z185i: 4.44x10 19 POT  MC le250z200i: 1.19x10 19 POT Data & MC cedar_phy daikon-cedar  The le010z185i data used corresponds to the same data used in the latest CC analysis and is evenly distributed along that period (runI + beginning of runII)  Thanks to Tricia for these pans !  POT values for DATA are after “good beam” cuts. all available !

MINOS 5  Data & reweighted MC antineutrino spectra: le010z185i le250z200i All MC   parent   parent  L parent  + parent Background All MC   parent   parent  L parent  + parent Background le010z185i le250z200i data/MC (no SKZP) data/MC data/MC (no SKZP) data/MC Note: SKZP “PiMinus_CedarDaikon”, run I configuration (more details in slides 16-17)

MINOS 6 Expected sensitivities  Before fitting the data tested the routine with fake data.  Used smoothed MC histograms (shown in grey) to construct scenario. (  + ) pHE (  + ) LE (  -,K - ) LE (  -,K - ) pHE Background LE Background pHE  Fake data is produced by statistically fluctuating the histograms.  The fit is done “manually” (no Minuit)

MINOS 7 Wassup with the bias Χ 2 best fit = 28.6  Scenario 1: “best possible” LE DATA POTpHE DATA POTLE MC POTpHE MC POT ∞ 1.41x10 19 ∞∞ One fake experiment Best fit  Distribution of 1000 fake experiments: Best possible stat. error Accuracy of contour confirmed by distribution of fake experiments 90% C.L. 68% C.L.  This is the best measurement we can do with the current amount of pHE data:

MINOS 8  Scenario 2: “now” LE DATA POTpHE DATA POTLE MC POTpHE MC POT 4.67x x x x10 19 Χ 2 best fit = 28.5 One fake experiment Best fit 90% C.L. 68% C.L.  Distribution of 1000 fake experiments:  This is the kind of measurement we expect to do now:

MINOS 9 Prob(25.4,28) = 60.6%  χ 2 =16.9 Preliminary results Χ2Χ2  Our results, with statistical uncertainties only: pHE(data) – LE(data) + C(MC) Best fit Nominal case (parLE=parHE=1) Best fit: parLE=1.525 ± 0.37 parHE=0.522 ± % C.L.68% C.L. Χ 2 best fit = 25.4 pHE(data) – LE(data) + C(MC) Prob(42.3,28) = 4.1%

MINOS 10 par LEpar HE χ 2 best fit Normal No SKZP No Bkgd substraction SKZP Consistent with expectation as described in minos-doc 2909 Preliminary results  Fit results in other conditions:  Difference with “No SKZP” case stems mainly from ~15% difference in low energy (< 10 GeV) region of C:  How much of this change is attributed to hadron production only by SKZP, and how much to other effects? ratio

MINOS 11 Outlook  How much more can the result be improved? (without taking more data) For an infinite amount of pHE MC, LE data and LE MC →max. goal  Contours calculated assuming same best fit value and 1.41x10 19 POT of pHE data: For an infinite amount of LE data and LE MC, with current amount of pHE MC (1.3x10 19 POT) LE data =2x10 20 POT LE MC =2.5x10 20 POT with current amount of pHE MC  LE data & MC POT of ~2x10 20 POT is already “infinite” for our purposes.  With ~5 times more pHE MC can get close to the max. goal LE data =2x10 20 POT LE MC =2.5x10 20 POT pHE MC = 7x10 19 POT

MINOS 12 Summary  Our preliminary results confirm the SKZP prediction of    to 1.4  (statistics only)  A couple of things left to do:  Run with more data & MC. Need ~5 times more pHE MC.  Assign a systematic error to our measurement  A much smaller systematic error could be obtained by doing the measurement with pME data, as shown in minos-doc 2706.

MINOS 13 Backup

MINOS 14 le010z185i le250z200i  Data & raw MC antineutrino spectra: All MC   parent   parent  L parent  + parent Background All MC   parent   parent  L parent  + parent Background le010z185i le250z200i data/MC

MINOS 15  Applied SKZP to the MC: All MC   parent  L parent   parent  + parent Background raw MC SKZP MC le010z185i ratio

MINOS 16 le250z200i bkgd (Reweighted for runI) le250z200i bkgd (Reweighted for runII)  difference  Reweighting in runI or in runII modality does not change the antineutrinos at all.  What about the background (made mostly of CC  ’s)?  Difference between the plots above is tiny !  Reweighted everything for runI. → What about the two running periods?

MINOS 17  Scale   component by best fit values and compare with data: Preliminary results le010z185i le250z200i All MC   parent   parent  L parent  + parent Background All MC   parent   parent  L parent  + parent Background le010z185i le250z200i data/MC (before) data/MC (after scaling) data/MC (before) data/MC (after scaling)

MINOS 18  χ 2 =35.2  Preliminary results (no SKZP) Real data Best fit Real data Nominal case (parLE=parHE=1) Best fit: parLE = 1.85 parHE = 0.44

MINOS 19 parLE = ± 0.37 parHE = ± 0.19  Χ 2 = 1.0 contour

MINOS 20 Max goal With 1.41x1019 POT of le250z200i data, stat error in only le250z200i data-MC With 1.41x1019 POT of le250z200i data, 2x1020 POT of le010z185i MC and 2.5x1020 POT of le010z185i Data With 1.41x1019 POT of le250z200i data, 2x1020 POT of le010z185i MC and 2.5x1020 POT of le010z185i Data, and 4x1019 POT of le250z200i MC Outlook

MINOS 21 With 1.41x1019 POT of le250z200i data, 2x1020 POT of le010z185i MC and 2.5x1020 POT of le010z185i Data, and 7x1019 POT of le250z200i MC With 1.41x1019 POT of le250z200i data, 2x1020 POT of le010z185i MC and 2.5x1020 POT of le010z185i Data, and 1x1020 POT of le250z200i MC With 1.41x1019 POT of le250z200i data, 2x1020 POT of le010z185i MC and 2.5x1020 POT of le010z185i Data, and 1.5x1020 POT of le250z200i MC