# Presentation: 941267

## First MiniBooNE  νe Appearance Results

- First MiniBooNE  νe Appearance Results

**Georgia Karagiorgi, MIT**
**FNAL ****– ****December 11, 2008**

## Outline

** ****Motivation for  ****ν****e**** appearance search**
** ****MiniBooNE Experiment**
** ****MiniBooNE  ****ν****e**** analysis**
** ****Results **
- Oscillation fits
- Implications for low energy excess** **observed in neutrino mode
** ****Future prospects and conclusions**

-            Y.Liu, D.Perevalov, I.Stancu
-             ***University of Alabama***
-             S.Koutsoliotas
-              ***Bucknell University*****  **
-  E.Hawker, R.A.Johnson, J.L.Raaf        ***University of Cincinnati***
-       T. L. Hart, R.H.Nelson, M.Tzanov, M.Wilking, E.D.Zimmerman
-              ***University of Colorado***
-   A.A.Aguilar-Arevalo, L.Bugel, L.Coney,
-  Z. Djurcic, K.B.M.Mahn, J.Monroe, D.Schmitz
-     M.H.Shaevitz, M.Sorel
-  ***Columbia University***
-     D.Smith  ***Embry Riddle Aeronautical University***
-       L.Bartoszek, C.Bhat, S.J.Brice
-       B.C.Brown, D. A. Finley, R.Ford, F.G.Garcia,
- C. Green, P.Kasper, T.Kobilarciik, I.Kourbanis,  A.Malensek, W.Marsh, P.Martin, F.Mills,
- C.D.Moore, E.Prebys, A.D.Russell , P.Spentzouris, R.J.Stefanski,  T. Williams ***Fermi National Accelerator Laboratory***
-  D.C.Cox, T.Katori, H.Meyer, C.C.Polly, R.Tayloe  ***Indiana University***** **
- H.Ray, B. Osmanov, J. Grange, J. Mousseau
-   ***University of Florida***
-  G.T.Garvey, A.Green, C.Green, W.C.Louis, G.McGregor, G.B.Mills, V.Sandberg, R.Schirato, Z. Pavlovic
-  R.Van de Water , D.H.White, G.P.Zeller       ***Los Alamos National Laboratory***

-                  R.Imlay, J.A. Nowak, W.Metcalf, S.Ouedraogo, M. Sung, M.O.Wascko
-  ***Louisiana State University***
- J.M.Conrad, G. Karagiorgi, V. Nguyen
***Massachusetts Institute of Technology***
-    J.Cao, Y.Liu, B.P.Roe, H.J.Yang     ***University of Michigan***
-  A.O.Bazarko, E. M. Laird, P.D.Meyers, R.B.Patterson, F.C.Shoemaker, H.A.Tanaka   ***Princeton University***
-                   P.Nienaber  ***Saint Mary's University of Minnesota***
-                        J. M. Link ***Virginia Polytechnic Institute***_   _
-  C.E Anderson, A.Curioni, B.T.Fleming,S.K. Linden, M. Soderberg
***Yale University***

**~80 physicists from ~18 institutions**

- 12/11/2008 FNAL W&C

## Appearance search @ LSND

*beam excess** *
*p(**ν**μ****ν**e**e**+**)n** *
*p(**ν**e**e**+**)n** *
*other** *

**Collected data from 1993 to 199****8**
**Liquid scintillator (Cherenkov) detector lined with PMT’s **
**Detected ****ν****e**** from stopped pion source: ****π****+ ********μ****+ ********ν****μ**
**observed excess:****87.9 ****± 22.4 ±**** 6.0 **** ****ν****e**** events (3.8****σ****) **

- _

- _

- _

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Appearance search @ LSND

**Collected data from 1993 to 199****8**
**Liquid scintillator (Cherenkov) detector lined with PMT’s **
**Detected ****ν****e**** from stopped pion source: ****π****+ ********μ****+ ********ν****μ**
**observed excess:****87.9 ****± 22.4 ±**** 6.0 **** ****ν****e**** events (3.8****σ****) **
**Possible interpretation:**
**2-neutrino mixing with **

*beam excess** *
*p(**ν**μ****ν**e**e**+**)n** *
*p(**ν**e**e**+**)n** *
*other** *

***P(******ν******μ************ ******ν******e******) = ******sin******2****** (2******θ******) sin******2****** ******(******	******                  ******)***
***	****** ******= 0.245 ******± 0.067 ± 0.045 %***

***1.27 L ******Δ******m******2***
***E***

- _

- _

- _

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Appearance search @ LSND

**Collected data from 1993 to 199****8**
**Liquid scintillator (Cherenkov) detector lined with PMT’s **
**Detected ****ν****e**** from stopped pion source: ****π****+ ********μ****+ ********ν****μ**
**observed excess:****87.9 ****± 22.4 ±**** 6.0 **** ****ν****e**** events (3.8****σ****) **
**Possible interpretation:**
**2-neutrino mixing with **

***P(******ν******μ************ ******ν******e******) = ******sin******2****** (2******θ******) sin******2****** ******(******	******                  ******)***
***	****** ******= 0.245 ******± 0.067 ± 0.045 %***

***1.27 L ******Δ******m******2***
***E***

- _

- _

- _

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Appearance search @ LSND

***However, under this oscillation interpretation:***
***  ***
********* ******requires new physics beyond the ******  standard three-neutrino mixing scenario***

**~1 eV****2**

**Δ****m****2****solar**** ****~ 8 x 10****-5**** eV****2**

**Δ****m****2****atm**** ~ 2.7 x 10****-3**** eV****2**

**vs.**

***Δ******m******2******solar****** + ******Δ******m******2******atm****** ≠ ******Δ******m******2******LSND***

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## LSND interpretation

**Sterile neutrino models**
**3+1**

**Δ****m****2****21**** ****=**** Δ****m****2****32**** ****=**** Δ****m****2****31**** = 0**

**Δ****m****2****41**** ****=**** Δ****m****2 ****~**** ****0.1-100 eV****2**

**At least 4 mass eigenstates ********at least 4 flavors**
**But measured ****Γ(****Z****→**** ****ν**** **** ****ν)**** ******** only 3 different *****active***** neutrinos**
**	****	****	****	******** ****1 *****sterile***** neutrino**

**ν****1**

**ν****2**

**ν****3**

**ν****4**

**ν****e**

**ν****μ**

**ν****τ**

**ν****s**

**2-****ν**** approximation:**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## LSND interpretation

**Sterile neutrino models**
**3+1**

**Δ****m****2****21**** ****=**** Δ****m****2****32**** ****=**** Δ****m****2****31**** = 0**

**Δ****m****2****41**** ****=**** Δ****m****2 ****~**** ****0.1-100 eV****2**

**ν****1**

**ν****2**

**ν****3**

**ν****4**

**Oscillation probability:**

**ν****e**

**ν****μ**

**ν****τ**

**ν****s**

***P(******ν******μ************ ******ν******e ******) = ******4******|******U******μ4******|******2******|******U******e4******|******2******sin******2******(1.27******Δ******m******2******41****** L/E) ***
***	******	******     ******= sin******2******2******θ****** sin******2******(1.27******Δ******m******2****** L/E)***

**2-****ν**** approximation:**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Outline

** ****Motivation for  ****ν****e**** appearance search**
** ****MiniBooNE Experiment**
** ****MiniBooNE  ****ν****e**** analysis**
** ****Results **
- Oscillation fits
- Implications for low energy excess** **observed in neutrino mode
** ****Future prospects and conclusions**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE experiment

**LSND test: 2-neutrino approximation **
**	******** ****testing simplest interpretation (+1 sterile neutrino)**
**	**
**	**
**	****P****(****ν****μ****→****ν****e****)**** = sin****2****2****θ****sin****2****(1.27****Δ****m****2****L[m]/E[MeV])**
**	*****Run in neutrino mode: incredible statistics!***

***Place detector to preserve LSND L/E:******	******MiniBooNE:     500 m / 800 MeV******	******LSND:******	******           30 m /   50 MeV***
***[Change detection method and systematics]***

- νe

- νμ

- ντ

- νs

- Δm221 = Δm232 = Δm231 = 0

- Δm241 = Δm2 ~ 0.1-100 eV2

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE experiment

**800 ton mineral oil Cherenkov detector****12 m in diameter (450 ton fiducial volume)****lined with**** 1280**** inner PMT’s, and 240 outer veto PMT’s**

**[****arXiv: 0806.4201[hep-ex], accepted by NIM A****]**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE experiment

**Appearance experiment: it looks for an excess of electron neutrino events in a predominantly muon neutrino beam**

**neutrino mode:          ****ν****μ****→**** ****ν****e**** ****oscillation search**
**antineutrino mode:   ****ν****μ****→ ν****e**** ****oscillation search**

**[Phys. Rev. Lett. 98, 231801 (2007)]**

**NEW RESULTS!**

**ν**** mode flux**

**ν**** mode flux**

- ~6% ν

- ~18% ν

- _

- _

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE νe appearance search (ν mode)

**Sensitivity and limit to ****ν****μ****→**** ****ν****e**** oscillations **

**[Phys. Rev. Lett. 98, 231801 (2007)]**

**MiniBooNE has ruled out (to 98%CL) the LSND**** ****result interpreted as ****ν****μ****→ν****e**** ****oscillations described with standard L/E dependence, which ****assumes two-neutrino oscillations, and no CP or CPT violation.****	****	**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE νe appearance search (ν mode)

**Null fit ****χ****2**** (prob):****	****9.1(91%)****	****     22.0(28%)**
**Best fit ****χ****2**** (prob):****	****7.2(93%)****	****     18.3(37%)**

- MiniBooNE νe appearance search (ν mode)

**At the same time, an unexpected ****excess of ****ν****e****-like events was observed at lower neutrino energies****  (200**** ****MeV**** ****<**** ****E****ν****QE**** ****<**** ****475**** ****MeV)**
**	****	****	****	****	****	****[See Aug. 1, 2008 W&C talk by C. Polly...]**

**After thorough investigation, excess still persists at the 3.0****σ ****level, and its source remains unknown... **
**This excess is incompatible with LSND under a two-neutrino oscillation hypothesis.**** **
**[paper to be submitted to PRL]**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## LSND interpretation?

**Sterile neutrino models**
**3+2 ******** next minimal ****extension to 3+1 models**

**Δ****m****2****21**** ****=**** Δ****m****2****32**** ****=**** Δ****m****2****31**** = 0**

**Δ****m****2****41**** ****~**** ****0.1-100 eV****2**

**ν****1**

**ν****2**

**ν****3**

**ν****4**

**ν****5**

**Δ****m****2****51**** ****~**** ****0.1-100 eV****2**

**2 independent ****Δ****m****2**
**4 mixing parameters**
**1 Dirac CP phase**

**ν****e**

**ν****μ**

**ν****τ**

**ν****s**

***P( ******ν******μ************ ******ν******e ******) = ******4******|******U******μ4******|******2******|******U******e4******|******2******sin******2******x******41****** + 4******|******U******μ******5******|******2******|******U******e5******|******2******sin******2******x******51****** +***
***                    ******+ 8 ******|******U******μ******5******||******U******e5******|******|******U******μ4******||******U******e4******|sinx******41******sinx******51******cos(x******54******±******φ******45****** ******)***

- (―)

- (―)

**Oscillation probability:**

- 3+2 models favorable by           fits to appearance data, including MiniBooNE neutrino mode result! *[hep-ph/0705.0107]*

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## LSND interpretation?

**Sterile neutrino models**
**3+2 ******** next minimal****extension to 3+1 models**

**Δ****m****2****21**** ****=**** Δ****m****2****32**** ****=**** Δ****m****2****31**** = 0**

**Δ****m****2****41**** ****~**** ****0.1-100 eV****2**

**ν****1**

**ν****2**

**ν****3**

**ν****4**

**ν****5**

**Δ****m****2****51**** ****~**** ****0.1-100 eV****2**

**2 independent ****Δ****m****2**
**4 mixing parameters**
**1 Dirac CP phase**

**ν****e**

**ν****μ**

**ν****τ**

**ν****s**

***P( ******ν******μ************ ******ν******e ******) = ******4******|******U******μ4******|******2******|******U******e4******|******2******sin******2******x******41****** + 4******|******U******μ******5******|******2******|******U******e5******|******2******sin******2******x******51****** +***
***                    ******+ 8 ******|******U******μ******5******||******U******e5******|******|******U******μ4******||******U******e4******|sinx******41******sinx******51******cos(x******54******±******φ******45****** ******)***

- (―)

- (―)

**Oscillation probability:**

-    ...and appealing due to         possibility they offer for CP violation in     leptonic sector!                           ***[hep-ph/0305255]***

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE low energy excess?

**Several possible explanations have been put forth by the physics community, attempting to reconcile the MiniBooNE neutrino mode result with LSND and other appearance experiments...**
**3+2 with CP violation ****[Maltoni and Schwetz, hep-ph0705.0107 ; G. K., NuFACT 07 conference]**
**Anomaly mediated photon production****[Harvey, Hill, and Hill, hep-ph0708.1281]**** **
**New light gauge boson ****[Nelson, Walsh, Phys. Rev. D 77, 033001 (2008)]**
**...**
**Some of them have ****fairly concrete ****predictions for a MiniBooNE antineutrino mode running**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Need a direct test of LSNDand another handle on the low energy excess

- Need a direct test of LSNDand another handle on the low energy excess

**First antineutrino results shown today correspond to 3.386E20 POT !**

**Big thanks to the accelerator division for record-high 0.121e20 POT delivered last week!!!**

**Fall 2007: approval for extended MiniBooNE antineutrino running to collect data for a total of 5.0e20 POT**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Need a direct test of LSNDand another handle on the low energy excess

- Need a direct test of LSNDand another handle on the low energy excess

**MiniBooNE E>200MeV****90% CL sensitivity**
**to ****ν****μ********ν****e**** oscillations**

-  _

-  _

**Recall, ****ν**** mode:**

**test of LSND in antineutrino mode**

**Direct test in antineutrino mode:**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE and the νSM

**Exploring new territories, far beyond the ****ν****SM !**
**Sterile neutrinos/CP violation ****[*****hep-ph/0305255*****]**
**Neutrino decay ****[*****hep-ph/0602083*****]**
**Extra dimensions ****[*****hep-ph/0504096*****]**
**CPT/Lorentz violation ****[*****PRD(2006)105009*****]**

- More standard...
- More extreme...

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Outline

** ****Motivation for  ****ν****e**** appearance search**
** ****MiniBooNE Experiment**
** ****MiniBooNE  ****ν****e**** analysis**
** ****Results **
- Oscillation fits
- Implications for low energy excess** **observed in neutrino mode
** ****Future prospects and conclusions**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE νe appearance analysis

- Same **blind** analysis chain as for neutrino mode...
- 							[***See Aug. 1, 2008 W&C talk by C. Polly...***]
- ...but different background, and
- 	different systematics...

**Beam Flux ****Prediction**

**Cross Section ****Model**

**Optical Model**

**Event ****Reconstruction**

**Particle ****Identification**

**Simultaneous ****Fit to **** ̄****μ**** and **** ̄****e**** ****events**

**Start with a Geant 4 flux prediction for the ******** spectrum from ******** and K produced at the target**

**Use track-based event reconstruction**

**Predict ******** interactions using the Nuance event generator**

**Pass final state particles to Geant 3 to model particle and light propagation in the tank**

**Fit reconstructed energy spectrum for oscillations**

**Use hit topology and timing to identify electron-like or muon-like Cherenkov rings and corresponding charged current neutrino interactions**

- ―

- ν

- ν

- _

- _

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE νe appearance analysis

- 							[***See Aug. 1, 2008 W&C talk by C. Polly...***]
- ...but different background, and
- 	different systematics...

- MiniBooNE νe appearance analysis

**Beam Flux ****Prediction**

**Cross Section ****Model**

**Optical Model**

**Event ****Reconstruction**

**Particle ****Identification**

**Simultaneous ****Fit to **** ̄****μ**** and **** ̄****e**** ****Events**

**Start with a Geant 4 flux prediction for the ******** spectrum from ******** and K produced at the target**

**Use track-based event reconstruction**

**Predict ******** interactions using the Nuance event generator**

**Pass final state particles to Geant 3 to model particle and light propagation in the tank**

**Fit reconstructed energy spectrum for oscillations**

**Use hit topology and timing to identify electron-like or muon-like Cherenkov rings and corresponding charged current neutrino interactions**

- ―

- ν

- ν

**Track-Based Analysis (TBA)**

- _

- _

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE νe appearance analysis

- 							[***See Aug. 1, 2008 W&C talk by C. Polly...***]
- ...but different background, and
- 	different systematics...

- MiniBooNE νe appearance analysis

**Beam Flux ****Prediction**

**Cross Section ****Model**

**Optical Model**

**Event ****Reconstruction**

**Particle ****Identification**

**Simultaneous ****Fit to **** ̄****μ**** and **** ̄****e**** ****Events**

**Start with a Geant 4 flux prediction for the ******** spectrum from ******** and K produced at the target**

**Use point-source event reconstruction**

**Predict ******** interactions using the Nuance event generator**

**Pass final state particles to Geant 3 to model particle and light propagation in the tank**

**Fit reconstructed energy spectrum for oscillations**

**Use reconstructed quantities such as time, charge likelihoods as inputs to boosted decision tree algorithms, trained on simulated signal events**

- ―

- ν

- ν

**also a Boosted-Decision-Tree analysis ****	****	****	****(BDT) as a cross-check**

**[Phys. Rev. Lett. 98, 231801 (2007)]**

- _

- _

- G. Karagiorgi

- 12/11/2008 FNAL W&C

##   What we want

-   What we want

**ν****e**** ****charged-current quasi-elastic events**
***ν******e****** + p ******→ ******e******+****** + n***

**e**

**π****0**

**μ**

**γ**** (shower)**

**γ**** (shower)**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

##   What we want

**e**

**π****0**

**μ**

-   What we want

**beam dominated by  ****ν****μ**** which interact **
**mainly though charged current quasi-elastic **
**(CCQE) channels... **
***ν******μ****** + p ******→ ******μ******+****** + n***
**(****μ**** ****  ****decay ******** second subevent)**

- don’t

*^*

**γ**** (shower)**

**γ**** (shower)**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

##   What we want

**e**

**γ**** (shower)**

**γ**** (shower)**

**π****0**

**μ**

-   What we want

**...****but some times through neutral current **
**channels, and can therefore**
**be mis-identified as  ****ν****e****’s... **
***	******	******	******	******For example, NC ******π******0******:***
***ν******μ****** + n/p ******→ n/p + ******π******0****** + ******ν******μ***
***	******	******             ****** ******π******0****** → γγ***

***...“******γ******” looks like “e” in a Cherenkov detector***

- don’t

*^*

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE νe appearance analysis

**Background composition for ****ν****e**** appearance search (3.386e20 POT):**

**N****events****	****      **** 200-475 MeV****	****475-1250 MeV**
**intrinsic ****ν****e         ****17.74****	****43.23****from ****π****±****/****μ****±          ****8.44****	****	****17.14****from K****±****, K****0        ****8.20****	****	****24.88****other ****ν****e****	****        1.11****	****	****1.21**
**mis-id ****ν****μ****	****            ****42.54**** ****	****14.55****CCQE****	****        2.86****	****	****1.24****NC**** π****0****	****   **** ****       ****24.60****	****7.17****Δ**** radiative      6.58****	****	****2.02****Dirt****	****        4.69****	****	****1.92****other ****ν****μ****	****        3.82****	****	****2.20**
**Total bkgd      60.29****	****57.78****	**
**LSND best fit  4.33****	****	****12.63**

- ―

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE νe appearance analysis

**Background composition for ****ν****e**** appearance search (3.386e20 POT):**

- ―

- W+

- p

- 

****

- n

- μ+ can...
- ...capture on C
- ...decay too quickly
- ...have too low energy

**N****events****	****      **** 200-475 MeV****	****475-1250 MeV**
**intrinsic ****ν****e         ****17.74****	****43.23****from ****π****±****/****μ****±          ****8.44****	****	****17.14****from K****±****, K****0        ****8.20****	****	****24.88****other ****ν****e****	****        1.11****	****	****1.21**
**mis-id ****ν****μ****	****            ****42.54**** ****	****14.55****CCQE****	****        2.86****	****	****1.24****NC**** π****0****	****   **** ****       ****24.60****	****7.17****Δ**** radiative      6.58****	****	****2.02****Dirt****	****        4.69****	****	****1.92****other ****ν****μ****	****        3.82****	****	****2.20**
**Total bkgd      60.29****	****57.78****	**
**LSND best fit  4.33****	****	****12.63**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE νe appearance analysis

**Background composition for ****ν****e**** appearance search (3.386e20 POT):**

- ―

- Z

- A

- 

- 

- 

**N****events****	****      **** 200-475 MeV****	****475-1250 MeV**
**intrinsic ****ν****e         ****17.74****	****43.23****from ****π****±****/****μ****±          ****8.44****	****	****17.14****from K****±****, K****0        ****8.20****	****	****24.88****other ****ν****e****	****        1.11****	****	****1.21**
**mis-id ****ν****μ****	****            ****42.54**** ****	****14.55****CCQE****	****        2.86****	****	****1.24****NC**** π****0****	****   **** ****       ****24.60****	****7.17****Δ**** radiative      6.58****	****	****2.02****Dirt****	****        4.69****	****	****1.92****other ****ν****μ****	****        3.82****	****	****2.20**
**Total bkgd      60.29****	****57.78****	**
**LSND best fit  4.33****	****	****12.63**

- Coherent π0 production

- A

**γ**

**γ**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE νe appearance analysis

**Background composition for ****ν****e**** appearance search (3.386e20 POT):**

- ―

- Z

- p

- 

- 

- 

**N****events****	****      **** 200-475 MeV****	****475-1250 MeV**
**intrinsic ****ν****e         ****17.74****	****43.23****from ****π****±****/****μ****±          ****8.44****	****	****17.14****from K****±****, K****0        ****8.20****	****	****24.88****other ****ν****e****	****        1.11****	****	****1.21**
**mis-id ****ν****μ****	****            ****42.54**** ****	****14.55****CCQE****	****        2.86****	****	****1.24****NC**** π****0****	****   **** ****       ****24.60****	****7.17****Δ**** radiative      6.58****	****	****2.02****Dirt****	****        4.69****	****	****1.92****other ****ν****μ****	****        3.82****	****	****2.20**
**Total bkgd      60.29****	****57.78****	**
**LSND best fit  4.33****	****	****12.63**

- Resonant π0 production

- 

- p

**γ**

**γ**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE νe appearance analysis

**Background composition for ****ν****e**** appearance search (3.386e20 POT):**

- ―

- Z

- p

****

- 

- 

**N****events****	****      **** 200-475 MeV****	****475-1250 MeV**
**intrinsic ****ν****e         ****17.74****	****43.23****from ****π****±****/****μ****±          ****8.44****	****	****17.14****from K****±****, K****0        ****8.20****	****	****24.88****other ****ν****e****	****        1.11****	****	****1.21**
**mis-id ****ν****μ****	****            ****42.54**** ****	****14.55****CCQE****	****        2.86****	****	****1.24****NC**** π****0****	****   **** ****       ****24.60****	****7.17****Δ**** radiative      6.58****	****	****2.02****Dirt****	****        4.69****	****	****1.92****other ****ν****μ****	****        3.82****	****	****2.20**
**Total bkgd      60.29****	****57.78****	**
**LSND best fit  4.33****	****	****12.63**

- ...and some times...
-   Δ radiative decay

- 

- p

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE νe appearance analysis

**Background composition for ****ν****e**** appearance search (3.386e20 POT):**

- ―

**N****events****	****      **** 200-475 MeV****	****475-1250 MeV**
**intrinsic ****ν****e         ****17.74****	****43.23****from ****π****±****/****μ****±          ****8.44****	****	****17.14****from K****±****, K****0        ****8.20****	****	****24.88****other ****ν****e****	****        1.11****	****	****1.21**
**mis-id ****ν****μ****	****            ****42.54**** ****	****14.55****CCQE****	****        2.86****	****	****1.24****NC**** π****0****	****   **** ****       ****24.60****	****7.17****Δ**** radiative      6.58****	****	****2.02****Dirt****	****        4.69****	****	****1.92****other ****ν****μ****	****        3.82****	****	****2.20**
**Total bkgd      60.29****	****57.78****	**
**LSND best fit  4.33****	****	****12.63**

- MiniBooNE detector

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE νe appearance analysis

**Background composition for ****ν****e**** appearance search (3.386e20 POT):**

- ―

**N****events****	****      **** 200-475 MeV****	****475-1250 MeV**
**intrinsic ****ν****e         ****17.74****	****43.23****from ****π****±****/****μ****±          ****8.44****	****	****17.14****from K****±****, K****0        ****8.20****	****	****24.88****other ****ν****e****	****        1.11****	****	****1.21**
**mis-id ****ν****μ****	****            ****42.54**** ****	****14.55****CCQE****	****        2.86****	****	****1.24****NC**** π****0****	****   **** ****       ****24.60****	****7.17****Δ**** radiative      6.58****	****	****2.02****Dirt****	****        4.69****	****	****1.92****other ****ν****μ****	****        3.82****	****	****2.20**
**Total bkgd      60.29****	****57.78****	**
**LSND best fit  4.33****	****	****12.63**

**LSND best-fit ****ν****μ**** ******** ν****e**** **
**(****Δ****m****2****, sin****2****2****θ****)=(1.2,0.003)**

- _

- _

**[note: statistical-only errors shown]**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE νe appearance analysis

**Background systematic uncertainties**

| Source

           EνQE range (MeV) | 

200-475 | 

475-1100 | 

200-475 | 

475-1100 |
| --- | --- | --- | --- | --- |
| Flux from π+/μ+ decay  | 0.4 | 0.7 | 1.8 | 2.2 |
| Flux from π-/μ- decay  | 3.3 | 2.2 | 0.1 | 0.2 |
| Flux from K+ decay | 2.3 | 4.9 | 1.4 | 5.7 |
| Flux from K- decay | 0.5 | 1.1 | - | - |
| Flux from K0 decay | 1.5 | 5.7 | 0.5 | 1.5 |
| Target and beam models | 1.9 | 3.0 | 1.3 | 2.5 |
| ν cross section  | 6.4 | 12.9 | 5.9 | 11.9 |
| NC π0 yield | 1.7 | 1.6 | 1.4 | 1.9 |
| Hadronic interactions | 0.5 | 0.6 | 0.8 | 0.3 |
| External interactions (dirt) | 2.4 | 1.2 | 0.8 | 0.4 |
| Optical model | 9.8 | 2.8 | 8.9 | 2.3 |
| Electronics & DAQ model | 9.7 | 3.0 | 5.0 | 1.7 |
| Total (unconstrained) | 16.3 | 16.2 | 12.3 | 14.2 |

- ―

**ν ****mode uncer. (%)**

**ν ****mode uncer. (%)**

**Come from propagating uncertainties from the HARP experiment using a spline interpolation of the HARP data**

**[****arXiv: 0806.1449 [hep-ex], ****	****submitted to PRD****]**

- _

## MiniBooNE νe appearance analysis

**Background systematic uncertainties**

| Source

           EνQE range (MeV) | 

200-475 | 

475-1100 | 

200-475 | 

475-1100 |
| --- | --- | --- | --- | --- |
| Flux from π+/μ+ decay  | 0.4 | 0.7 | 1.8 | 2.2 |
| Flux from π-/μ- decay  | 3.3 | 2.2 | 0.1 | 0.2 |
| Flux from K+ decay | 2.3 | 4.9 | 1.4 | 5.7 |
| Flux from K- decay | 0.5 | 1.1 | - | - |
| Flux from K0 decay | 1.5 | 5.7 | 0.5 | 1.5 |
| Target and beam models | 1.9 | 3.0 | 1.3 | 2.5 |
| ν cross section  | 6.4 | 12.9 | 5.9 | 11.9 |
| NC π0 yield | 1.7 | 1.6 | 1.4 | 1.9 |
| Hadronic interactions | 0.5 | 0.6 | 0.8 | 0.3 |
| External interactions (dirt) | 2.4 | 1.2 | 0.8 | 0.4 |
| Optical model | 9.8 | 2.8 | 8.9 | 2.3 |
| Electronics & DAQ model | 9.7 | 3.0 | 5.0 | 1.7 |
| Total (unconstrained) | 16.3 | 16.2 | 12.3 | 14.2 |

- ―

**ν ****mode uncer. (%)**

**ν ****mode uncer. (%)**

**[****arXiv: 0806.1449 [hep-ex], ****	****submitted to PRD****]**

- _

**Come from propagating uncertainties from Feynman Scaling to the world's K+ production data.**

## MiniBooNE νe appearance analysis

**Background systematic uncertainties**

| Source

           EνQE range (MeV) | 

200-475 | 

475-1100 | 

200-475 | 

475-1100 |
| --- | --- | --- | --- | --- |
| Flux from π+/μ+ decay  | 0.4 | 0.7 | 1.8 | 2.2 |
| Flux from π-/μ- decay  | 3.3 | 2.2 | 0.1 | 0.2 |
| Flux from K+ decay | 2.3 | 4.9 | 1.4 | 5.7 |
| Flux from K- decay | 0.5 | 1.1 | - | - |
| Flux from K0 decay | 1.5 | 5.7 | 0.5 | 1.5 |
| Target and beam models | 1.9 | 3.0 | 1.3 | 2.5 |
| ν cross section  | 6.4 | 12.9 | 5.9 | 11.9 |
| NC π0 yield | 1.7 | 1.6 | 1.4 | 1.9 |
| Hadronic interactions | 0.5 | 0.6 | 0.8 | 0.3 |
| External interactions (dirt) | 2.4 | 1.2 | 0.8 | 0.4 |
| Optical model | 9.8 | 2.8 | 8.9 | 2.3 |
| Electronics & DAQ model | 9.7 | 3.0 | 5.0 | 1.7 |
| Total (unconstrained) | 16.3 | 16.2 | 12.3 | 14.2 |

- ―

**ν ****mode uncer. (%)**

**ν ****mode uncer. (%)**

**[****arXiv: 0806.1449 [hep-ex], ****	****submitted to PRD****]**

- _

**Come from propagating the uncertainties from Sanford Wang to the world K0L production data.**

## MiniBooNE νe appearance analysis

**Background systematic uncertainties**

| Source

           EνQE range (MeV) | 

200-475 | 

475-1100 | 

200-475 | 

475-1100 |
| --- | --- | --- | --- | --- |
| Flux from π+/μ+ decay  | 0.4 | 0.7 | 1.8 | 2.2 |
| Flux from π-/μ- decay  | 3.3 | 2.2 | 0.1 | 0.2 |
| Flux from K+ decay | 2.3 | 4.9 | 1.4 | 5.7 |
| Flux from K- decay | 0.5 | 1.1 | - | - |
| Flux from K0 decay | 1.5 | 5.7 | 0.5 | 1.5 |
| Target and beam models | 1.9 | 3.0 | 1.3 | 2.5 |
| ν cross section  | 6.4 | 12.9 | 5.9 | 11.9 |
| NC π0 yield | 1.7 | 1.6 | 1.4 | 1.9 |
| Hadronic interactions | 0.5 | 0.6 | 0.8 | 0.3 |
| External interactions (dirt) | 2.4 | 1.2 | 0.8 | 0.4 |
| Optical model | 9.8 | 2.8 | 8.9 | 2.3 |
| Electronics & DAQ model | 9.7 | 3.0 | 5.0 | 1.7 |
| Total (unconstrained) | 16.3 | 16.2 | 12.3 | 14.2 |

- ―

**ν ****mode uncer. (%)**

**ν ****mode uncer. (%)**

**[****arXiv: 0806.1449 [hep-ex], ****	****submitted to PRD****]**

- _

**Determined by special runs of the beam Monte Carlo where all the beam uncertainties not coming from meson production by 8 GeV protons are varied one at a time. These variations are treated as 1****σ ****excursions and**
**propagated into a final error matrix.**

## MiniBooNE νe appearance analysis

**Background systematic uncertainties**

| Source

           EνQE range (MeV) | 

200-475 | 

475-1100 | 

200-475 | 

475-1100 |
| --- | --- | --- | --- | --- |
| Flux from π+/μ+ decay  | 0.4 | 0.7 | 1.8 | 2.2 |
| Flux from π-/μ- decay  | 3.3 | 2.2 | 0.1 | 0.2 |
| Flux from K+ decay | 2.3 | 4.9 | 1.4 | 5.7 |
| Flux from K- decay | 0.5 | 1.1 | - | - |
| Flux from K0 decay | 1.5 | 5.7 | 0.5 | 1.5 |
| Target and beam models | 1.9 | 3.0 | 1.3 | 2.5 |
| ν cross section  | 6.4 | 12.9 | 5.9 | 11.9 |
| NC π0 yield | 1.7 | 1.6 | 1.4 | 1.9 |
| Hadronic interactions | 0.5 | 0.6 | 0.8 | 0.3 |
| External interactions (dirt) | 2.4 | 1.2 | 0.8 | 0.4 |
| Optical model | 9.8 | 2.8 | 8.9 | 2.3 |
| Electronics & DAQ model | 9.7 | 3.0 | 5.0 | 1.7 |
| Total (unconstrained) | 16.3 | 16.2 | 12.3 | 14.2 |

- ―

**ν ****mode uncer. (%)**

**ν ****mode uncer. (%)**

- _

**Come from propagating the uncertainties on a number of neutrino cross-section parameters (e.g. M****A****)...**
**...****many of which come from fits to (high statistics) MiniBooNE ****ν****μ**** data. **
**See, e.g.,**
**[****Phys. Rev. Lett. 100, 032301 (2008)****]**

## MiniBooNE νe appearance analysis

**Background systematic uncertainties**

| Source

           EνQE range (MeV) | 

200-475 | 

475-1100 | 

200-475 | 

475-1100 |
| --- | --- | --- | --- | --- |
| Flux from π+/μ+ decay  | 0.4 | 0.7 | 1.8 | 2.2 |
| Flux from π-/μ- decay  | 3.3 | 2.2 | 0.1 | 0.2 |
| Flux from K+ decay | 2.3 | 4.9 | 1.4 | 5.7 |
| Flux from K- decay | 0.5 | 1.1 | - | - |
| Flux from K0 decay | 1.5 | 5.7 | 0.5 | 1.5 |
| Target and beam models | 1.9 | 3.0 | 1.3 | 2.5 |
| ν cross section  | 6.4 | 12.9 | 5.9 | 11.9 |
| NC π0 yield | 1.7 | 1.6 | 1.4 | 1.9 |
| Hadronic interactions | 0.5 | 0.6 | 0.8 | 0.3 |
| External interactions (dirt) | 2.4 | 1.2 | 0.8 | 0.4 |
| Optical model | 9.8 | 2.8 | 8.9 | 2.3 |
| Electronics & DAQ model | 9.7 | 3.0 | 5.0 | 1.7 |
| Total (unconstrained) | 16.3 | 16.2 | 12.3 | 14.2 |

- ―

**ν ****mode uncer. (%)**

**ν ****mode uncer. (%)**

- _

**Come from propagating the error matrix produced by MiniBooNE's**** π****0**** ****rate measurement.**

**[****Phys. Lett. B664, 41 (2008)****]**

## MiniBooNE νe appearance analysis

**Background systematic uncertainties**

| Source

           EνQE range (MeV) | 

200-475 | 

475-1100 | 

200-475 | 

475-1100 |
| --- | --- | --- | --- | --- |
| Flux from π+/μ+ decay  | 0.4 | 0.7 | 1.8 | 2.2 |
| Flux from π-/μ- decay  | 3.3 | 2.2 | 0.1 | 0.2 |
| Flux from K+ decay | 2.3 | 4.9 | 1.4 | 5.7 |
| Flux from K- decay | 0.5 | 1.1 | - | - |
| Flux from K0 decay | 1.5 | 5.7 | 0.5 | 1.5 |
| Target and beam models | 1.9 | 3.0 | 1.3 | 2.5 |
| ν cross section  | 6.4 | 12.9 | 5.9 | 11.9 |
| NC π0 yield | 1.7 | 1.6 | 1.4 | 1.9 |
| Hadronic interactions | 0.5 | 0.6 | 0.8 | 0.3 |
| External interactions (dirt) | 2.4 | 1.2 | 0.8 | 0.4 |
| Optical model | 9.8 | 2.8 | 8.9 | 2.3 |
| Electronics & DAQ model | 9.7 | 3.0 | 5.0 | 1.7 |
| Total (unconstrained) | 16.3 | 16.2 | 12.3 | 14.2 |

- ―

**ν ****mode uncer. (%)**

**ν ****mode uncer. (%)**

- _

**Come from propagating the uncertainties in a number of hadronic processes, mainly photonuclear interaction final state uncertainties.**

## MiniBooNE νe appearance analysis

**Background systematic uncertainties**

| Source

           EνQE range (MeV) | 

200-475 | 

475-1100 | 

200-475 | 

475-1100 |
| --- | --- | --- | --- | --- |
| Flux from π+/μ+ decay  | 0.4 | 0.7 | 1.8 | 2.2 |
| Flux from π-/μ- decay  | 3.3 | 2.2 | 0.1 | 0.2 |
| Flux from K+ decay | 2.3 | 4.9 | 1.4 | 5.7 |
| Flux from K- decay | 0.5 | 1.1 | - | - |
| Flux from K0 decay | 1.5 | 5.7 | 0.5 | 1.5 |
| Target and beam models | 1.9 | 3.0 | 1.3 | 2.5 |
| ν cross section  | 6.4 | 12.9 | 5.9 | 11.9 |
| NC π0 yield | 1.7 | 1.6 | 1.4 | 1.9 |
| Hadronic interactions | 0.5 | 0.6 | 0.8 | 0.3 |
| External interactions (dirt) | 2.4 | 1.2 | 0.8 | 0.4 |
| Optical model | 9.8 | 2.8 | 8.9 | 2.3 |
| Electronics & DAQ model | 9.7 | 3.0 | 5.0 | 1.7 |
| Total (unconstrained) | 16.3 | 16.2 | 12.3 | 14.2 |

- ―

**ν ****mode uncer. (%)**

**ν ****mode uncer. (%)**

- _

**Come from propagating the uncertainty in MiniBooNE's**** ****dirt**** ****rate measurement.**

## MiniBooNE νe appearance analysis

**Background systematic uncertainties**

| Source

           EνQE range (MeV) | 

200-475 | 

475-1100 | 

200-475 | 

475-1100 |
| --- | --- | --- | --- | --- |
| Flux from π+/μ+ decay  | 0.4 | 0.7 | 1.8 | 2.2 |
| Flux from π-/μ- decay  | 3.3 | 2.2 | 0.1 | 0.2 |
| Flux from K+ decay | 2.3 | 4.9 | 1.4 | 5.7 |
| Flux from K- decay | 0.5 | 1.1 | - | - |
| Flux from K0 decay | 1.5 | 5.7 | 0.5 | 1.5 |
| Target and beam models | 1.9 | 3.0 | 1.3 | 2.5 |
| ν cross section  | 6.4 | 12.9 | 5.9 | 11.9 |
| NC π0 yield | 1.7 | 1.6 | 1.4 | 1.9 |
| Hadronic interactions | 0.5 | 0.6 | 0.8 | 0.3 |
| External interactions (dirt) | 2.4 | 1.2 | 0.8 | 0.4 |
| Optical model | 9.8 | 2.8 | 8.9 | 2.3 |
| Electronics & DAQ model | 9.7 | 3.0 | 5.0 | 1.7 |
| Total (unconstrained) | 16.3 | 16.2 | 12.3 | 14.2 |

- ―

**ν ****mode uncer. (%)**

**ν ****mode uncer. (%)**

- _

**These are uncertainties in light creation, propagation, and detection in the Tank. They are assessed though a set of 130 MC “multisims” that have been run where all these parameters are varied according to their input uncertainties.**

## MiniBooNE νe appearance analysis

**Background systematic uncertainties**

| Source

           EνQE range (MeV) | 

200-475 | 

475-1100 | 

200-475 | 

475-1100 |
| --- | --- | --- | --- | --- |
| Flux from π+/μ+ decay  | 0.4 | 0.7 | 1.8 | 2.2 |
| Flux from π-/μ- decay  | 3.3 | 2.2 | 0.1 | 0.2 |
| Flux from K+ decay | 2.3 | 4.9 | 1.4 | 5.7 |
| Flux from K- decay | 0.5 | 1.1 | - | - |
| Flux from K0 decay | 1.5 | 5.7 | 0.5 | 1.5 |
| Target and beam models | 1.9 | 3.0 | 1.3 | 2.5 |
| ν cross section  | 6.4 | 12.9 | 5.9 | 11.9 |
| NC π0 yield | 1.7 | 1.6 | 1.4 | 1.9 |
| Hadronic interactions | 0.5 | 0.6 | 0.8 | 0.3 |
| External interactions (dirt) | 2.4 | 1.2 | 0.8 | 0.4 |
| Optical model | 9.8 | 2.8 | 8.9 | 2.3 |
| Electronics & DAQ model | 9.7 | 3.0 | 5.0 | 1.7 |
| Total (unconstrained) | 16.3 | 16.2 | 12.3 | 14.2 |

- ―

**ν ****mode uncer. (%)**

**ν ****mode uncer. (%)**

- _

**These are uncertainties in our knowledge of the detector. A set of “unisim” variations are run and a matrix results from propagating these variations, treating them as 1****σ**** variations.**

## MiniBooNE νe appearance analysis

**Background systematic uncertainties**

| Source

           EνQE range (MeV) | 

200-475 | 

475-1100 | 

200-475 | 

475-1100 |
| --- | --- | --- | --- | --- |
| Flux from π+/μ+ decay  | 0.4 | 0.7 | 1.8 | 2.2 |
| Flux from π-/μ- decay  | 3.3 | 2.2 | 0.1 | 0.2 |
| Flux from K+ decay | 2.3 | 4.9 | 1.4 | 5.7 |
| Flux from K- decay | 0.5 | 1.1 | - | - |
| Flux from K0 decay | 1.5 | 5.7 | 0.5 | 1.5 |
| Target and beam models | 1.9 | 3.0 | 1.3 | 2.5 |
| ν cross section  | 6.4 | 12.9 | 5.9 | 11.9 |
| NC π0 yield | 1.7 | 1.6 | 1.4 | 1.9 |
| Hadronic interactions | 0.5 | 0.6 | 0.8 | 0.3 |
| External interactions (dirt) | 2.4 | 1.2 | 0.8 | 0.4 |
| Optical model | 9.8 | 2.8 | 8.9 | 2.3 |
| Electronics & DAQ model | 9.7 | 3.0 | 5.0 | 1.7 |
| Total (unconstrained) | 16.3 | 16.2 | 12.3 | 14.2 |

- ―

**ν ****mode uncer. (%)**

**ν ****mode uncer. (%)**

- _

**Similar systematics ****as for neutrino appearance search, ****but **
- Antineutrino  appearance  search  is more _statistics_  limited!

## Fit method

**The high-statistics ****ν****μ**** CCQE sample (78% ****ν****μ****, ****22****% ν****μ****) ****is well understood.**
**Total number of ****ν****μ**** ****CCQE data events after selection cuts: 14,193****	**

**ν****μ**** disappearance search!**
**See Oct. 31, 2008 W&C talk by K. Mahn...**
**[paper to be submitted to PRL]**

**(after tuning)**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Fit method

**The following three distinct samples are used in the oscillation fits, obtained using the same selection requirements used in neutrino mode analysis:**
**Background** to νe oscillations
**ν****e**** Signal** prediction (dependent on Δm2, sin22θ)
**ν****μ**** CCQE** sample, used to constrain νe prediction (signal+background)

**N****events**

**E****ν****QE**** bins**

***(MC prediction not to scale)***

- ―

- ―

- ―

**1,..., N**

**1,..., N**

**1,..., N**

**ν****e**

**ν****e**

**CCQE**
**ν****μ**

**N****events**

**E****ν****QE**** bins**

***(Data prediction not to scale)***

**1,..., N**

**ν****e**

**1,..., N**

**CCQE**
**ν****μ**

- ―

**(E****ν****QE**** scale repeats)**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Fit method

**The following three distinct samples are used in the oscillation fits, obtained using the same selection requirements used in neutrino mode analysis:**
**Background** to νe oscillations
**ν****e**** Signal** prediction (dependent on Δm2, sin22θ)
**ν****μ**** CCQE** sample, used to constrain νe prediction (signal+background)

- ―

- ―

- ―

- ―

***χ******2****** ******calculated using both datasets ( ******ν******e****** ******and  ******ν******μ****** CCQE), and corresponding covariance matrix***

- _

- _

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Fit method

**Fitting to the ****ν****μ**** CCQE and ****ν****e**** ****spectra simultaneously takes advantage of strong ****correlations between  ****ν****e**** ****signal, background, and the  ****ν****μ**** CCQE sample in order to reduce systematic uncertainties and constraining**** intrinsic  ****ν****e**** from muon decay**

**π****-**** ****→**** ****μ****-**** + ****ν****μ**
**	**
**             **** ****μ****-**** ****→**** ****e****-**** + ****ν****μ**** + ****ν****e**

**R****(ν****μ****) = ****Φ****(****ν****μ****)**** ****x**** σ(ν****μ****) ****x**** ****ε(ν****μ****)**

**R****(ν****e****) = ****Φ****(****ν****e****)**** ****x**** σ(ν****e****) ****x**** ****ε(ν****e****)**

**Kinematic distributions of ****π****+**** contributing to ****ν****μ**** ****and ****ν****e**** flux (****ν**** mode)**

**Example:**

**θ****π+**** (****radians)**

**p****π+**** (GeV/c)**

**θ****π+**** (****radians)**

**p****π+**** (GeV/c)**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Fit method

**This improves sensitivity and provides a stronger constraint to oscillations**** ******

**Effect of ****ν****μ**** ****CCQE constraint on sensitivity**

**Fitting to the ****ν****μ**** CCQE and ****ν****e**** ****spectra simultaneously takes advantage of strong ****correlations between  ****ν****e**** ****signal, background, and the  ****ν****μ**** CCQE sample in order to reduce systematic uncertainties and constraining**** intrinsic  ****ν****e**** from muon decay**

**90% CL sensitivity**
**E****ν****QE ****> 200 MeV**

**with ****ν****μ****CCQE**** constraint**

**without ****ν****μ****CCQE**** constraint**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE sensitivity to νμ→ νe

- MiniBooNE sensitivity to νμ→ νe

**Given neutrino mode results, ****two fits were considered ****for ****ν****e**** candidate events with ****TBA:**
**	**
**	****E****ν****QE ****> 475 MeV**
**	****E****ν****Q****Ε**** ****> 200 MeV**
**For BDT analysis: ****E ****ν****Q****Ε**** ****> 500 MeV**

**MiniBooNE sensitivity for ****3.386E20 POT**

- ―

- ―

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE sensitivity to νμ→ νe

- MiniBooNE sensitivity to νμ→ νe

**Effect of E****ν****QE ****threshold on sensitivity:**
**	****E****ν****QE ****> 475 MeV**
**	****E****ν****Q****Ε**** ****> 200 MeV**

**90% CL MiniBooNE sensitivity for 3.386E20 POT**

**P ~ sin****2****( 1.27 ****Δ****m****2****[****eV****2****] L[****m****] / E[****MeV****] )**
**	**
******fitting to lower energy increases sensitivity for lower ****Δ****m****2**

- ―

- ―

**~ ****Δ****m****2****/E ~ 1 for maximum sensitivity**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE νe appearance analysis

**Several cross-checks have been performed:**
**M****A****, ****κ**** checks, neutrino component in antineutrino ****(****WS) measurement **
**New ****π****0**** measurement**
**New dirt fraction extracted**
**Data quality checks (different periods of running, R/E****vis**** distributions)**
**BDT analysis**

- ―

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Outline

** ****Motivation for  ****ν****e**** appearance search**
** ****MiniBooNE Experiment**
** ****MiniBooNE  ****ν****e**** analysis**
** ****Results **
- Oscillation fits
- Implications for low energy excess** **observed in neutrino mode
** ****Future prospects and conclusions**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Results: Fits to EνQE > 200 MeV

- Results: Fits to EνQE > 200 MeV

**ν****e**** ****data vs. background distribution (3.386e20 POT):**

**low energy region**

**signal region**

***	******χ******2******null****** ******(dof) = 24.51 (19)***
***χ******2******-******probability = 17.7%***
***(calculated using error matrix at null)****** ***
**data statistical uncertainty**
**MC unconstrained systematic uncertainty**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Fit summary

** ****χ****2****null****(dof)****	****χ****2****null****(dof)*********            ****	****χ****2****best-fit****(dof)*********	****χ****2****LSND best-fit****(dof)**
** ****χ****2****-prob****	****	****χ****2****-prob****	****	****χ****2****-prob****	****	****χ****2****-prob**
** ****24.51(19)****	****20.18(17)****	****	****18.18(17)****	****	****20.14(19)**
** ****17.7%****	****	****26.5%****	****	****37.8%****	****	****38.6%**
** ****22.19(16)****	****17.88(14)****	****	****15.91(14)****	****	****17.63(16)**
** ****13.7%****	****	****21.2%****	****	****31.9%****	****	****34.6%**

**E****ν****QE****  fit**
**> ****200 ****MeV**
**> 475 MeV**

**E****ν****QE**** > 200 MeV and E****ν****QE**** > 475 MeV fits are consistent with each-other.**
**No strong evidence for oscillations in antineutrino mode.****(3.386e20 POT)**

**(*********Covariance matrix approximated to be the same everywhere by its value at best fit point)**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE limit to νμ νe oscillations

**1-sided raster limit:**** **

**No strong evidence for ****oscillations ******

**MB limit**
**(3.386e20 POT)**

**E>200 MeV**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE limit to νμ νe oscillations

- MiniBooNE limit to νμ νe oscillations

**1-sided raster limit:**** **

**No strong evidence for ****oscillations ******

**MB limit**
**(3.386e20 POT)**

**E>475 MeV**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Oscillation fits to EνQE > 200 MeV

***χ******2******best-fit******(dof) = 18.18 (17)***
***χ******2******-probability = 37.8%***

**Excess distribution and comparison with possible signal predictions:**

**MiniBooNE best-fit:**
**(****Δ****m****2****, sin****2****2****θ****) = (4.4 eV****2****, 0.004)**
**(E>200MeV)**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Complementary information: Evisible

**Excess distribution as a function of E****visible**** and comparison with possible signal predictions:**

- Error bars indicatedata statistical and constrainedbkgd systematic uncertainty

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Events summary (constrained syst + stat uncertainty)

**Events summary (constrained syst + stat uncertainty)**

***E******ν******QE****** range (MeV)******	******     ******	******	******	******ν ******mode ******	******	******ν****** mode ******	******	******	******	******	******	******	******(3.386e20 POT)******	******(6.486e20 POT)***
***200-300***
***300-475***
***200-475***
***475-1250***
***	***

**Excess**
**Deficit**

***Data******	******	******	******24******	******	******232***
***MC ******±****** sys+stat (constr.)******	******	******27.2 ******± 7.4******	******	******186.8 ******± 26.0***
***Excess (******σ******)******	******	******	******-3.2 ******± 7.4 ******(-0.4******σ******)******	******45.2 ******± 26.0 ******(1.7******σ******)***

***Data******	******	******	******37******	******	******312***
***MC ******±****** sys+stat (constr.)******	******	******34.3 ± 7.3******	******	******228.3 ± 24.5***
***Excess (******σ******)******	******	******	******2.7 ******± 7.3 ******(0.4******σ******)******	******83.7 ******± 24.5 ******(3.4******σ******)***

***Data******	******	******	******61******	******	******544***
***MC ******±****** sys+stat (constr.)******	******	******61.5 ± 11.7******	******	******415.2 ± 43.4***
***Excess (******σ******)******	******	******	******-0.5 ******± 11.7 ******(-0.04******σ******)******	******128.8****** ± 43.4 ******(3.0******σ******)***

***Data******	******	******	******61******	******	******408***
***MC ******±****** sys+stat (constr.)******	******	******57.8 ± 10.0******	******	******385.9 ± 35.7***
***Excess (******σ******)******	******	******	******3.2 ******± 10.0 ******(0.3******σ******)******	******22.1****** ± 35.7 ******(0.6******σ******)***

***[paper to be ******submitted to PRL]***

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Implications for low energy excess

**How consistent are excesses in neutrino and antineutrino mode under different ****underlying hypotheses**** as the source of the low energy excess in neutrino mode?**

***Data******	******	******	******61******	******	******544***
***MC ******±****** sys+stat (constr.)******	******	******61.5 ± 11.7******	******	******415.2 ± 43.4***
***Excess (******σ******)******	******	******	******-0.5 ******± 11.7****** ******(-0.04******σ******)******	******128.8****** ± 43.4 ******(3.0******σ******)***

***200-475 MeV***

- ν

- ν

- _

**Scales with POT **
**Same NC cross section for neutrinos and antineutrinos**** **
**Scales as ****π****0**** ****background **
**Scales with neutrinos (not antineutrinos)**
**Scales with background **
**Scales as the rate of Charged-Current interactions**
**Scales with Kaon rate at low energy**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Implications for low energy excess

***Data******	******	******	******61******	******	******544***
***MC ******±****** sys+stat (constr.)******	******	******61.5 ± 11.7******	******	******415.2 ± 43.4***
***Excess (******σ******)******	******	******	******-0.5 ******± 11.7****** ******(-0.04******σ******)******	******128.8****** ± 43.4 ******(3.0******σ******)***

***200-475 MeV***

**Performed 2-bin ****χ****2**** test for each assumption**
**Calculated ****χ****2**** ****probability assuming 1 dof**
**	****The underlying signal for each hypothesis, S,  was allowed to vary ****(thus accounting for the possibility that the observed signal in neutrino mode was a fluctuation up, and the observed signal in antineutrino mode was a fluctuation down),**** and an absolute ****χ****2**** minimum was found.****	**
**Three extreme fit scenarios were considered:**
**Statistical-only**** uncertainties**
**Statistical + fully-correlated systematics**** **
**Statistical + fully-uncorrelated systematics**

- ν

- ν

- _

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Implications for low energy excess

**Eg.: ****scales with POT *****(e.g. K******0L******,...)***
**Antineutrino POT: 3.386e20****	****	****Antineutrino POT****	**
**Neutrino POT: 6.486e20****	****	****	****   Neutrino POT**
**One would expect a ****ν ****excess of ~(128.8 events)*0.52 = ~67 events**

***Data******	******	******	******61******	******	******544***
***MC ******±****** sys+stat (constr.)******	******	******61.5 ± 11.7******	******	******415.2 ± 43.4***
***Excess (******σ******)******	******	******	******-0.5 ******± 11.7****** ******(-0.04******σ******)******	******128.8****** ± 43.4 ******(3.0******σ******)***

***200-475 MeV***

- Obviously this should be highly disfavored by the data, but one could imagine a scenario where the neutrino mode observed excess is a fluctuation up from true underlying signal and the antineutrino mode excess is a fluctuation down, yielding a lower χ2...

**= 0.52**

- ν

- ν

- _

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Implications for low energy excess

**Eg.: ****Same NC cross section for neutrinos and antineutrinos *****(e.g., HHH axial anomaly)***
**Expected rates obtained by ****integrating flux across all energies ****for neutrino mode, and antineutrino ****mode**

***Data******	******	******	******61******	******	******544***
***MC ******±****** sys+stat (constr.)******	******	******61.5 ± 11.7******	******	******415.2 ± 43.4***
***Excess (******σ******)******	******	******	******-0.5 ******± 11.7****** ******(-0.04******σ******)******	******128.8****** ± 43.4 ******(3.0******σ******)***

***200-475 MeV***

- ν

- ν

- _

**[Harvey, Hill, and Hill, hep-ph0708.1281]**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Implications for low energy excess

**Eg.: ****Scales as ****π****0**** background ****(same NC ****ν ****and ****ν ****cross-section ratio)**
**Expected rates obtained by integrating flux across all energies for neutrino mode, and antineutrino mode**
**Mis-estimation of ****π****0**** background?**** **
**Or other Neutral-Current process?**** **
**	****For ****π****0**** background to fully account for MB ****ν**** mode excess, it would have to be mis-estimated by a factor of two...**
**	****...****but we have measured MB ****π****0**** ****event rate**** ****to 5%!**** ****	**

***Data******	******	******	******61******	******	******544***
***MC ******±****** sys+stat (constr.)******	******	******61.5 ± 11.7******	******	******415.2 ± 43.4***
***Excess (******σ******)******	******	******	******-0.5 ******± 11.7****** ******(-0.04******σ******)******	******128.8****** ± 43.4 ******(3.0******σ******)***

***200-475 MeV***

- ν

- ν

- _

**[****Phys. Lett. B664, 41 (2008)****]**

- _

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Implications for low energy excess

**Eg.: ****Scales with neutrinos (in both running modes)**
**In ****neutrino mode, 94%**** of flux consists of ****neutrinos**
**In ****antineutrino mode,**** 82% of flux consists of antineutrinos, ****18%**** of flux consists of ****neutrinos**
**Predictions are allowed to scale according to ****neutrino**** content of the beam**

***Data******	******	******	******61******	******	******544***
***MC ******±****** sys+stat (constr.)******	******	******61.5 ± 11.7******	******	******415.2 ± 43.4***
***Excess (******σ******)******	******	******	******-0.5 ******± 11.7****** ******(-0.04******σ******)******	******128.8****** ± 43.4 ******(3.0******σ******)***

***200-475 MeV***

- ν

- ν

- _

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Implications for low energy excess

**Same  ****ν**** and ****ν ****NC cross-section (HHH axial anomaly)****, ****POT scaled, Low-E Kaon scaled: strongly disfavored as an explanation of the MiniBooNE low energy excess!**
**The most preferred model is that where the low-energy excess comes from neutrinos in the beam (no contribution from anti-neutrinos).**

**Currently in process of more careful consideration of **_**correlation**_** of systematics in neutrino and antineutrino mode... results coming soon!**

**	****	****Stat Only****	****Correlated Syst****	****Uncorrelated Syst**
**Same ****ν****,****ν ****NC  ****	****0.1%****	****	****0.1%****	****	****6.7%****NC ****π****0**** scaled****	****3.6%****	****	****6.4%****	****	****21.5%****POT scaled****	****0.0%****	****	****0.0%****	****	****1.8%****Bkgd scaled****	****2.7%****	****	****4.7%****	****	****19.2%****CC scaled****	****2.9%****	****	****5.2%****	****	****19.9%****Low-E Kaons****	****0.1%****	****	****0.1%****	****	****5.9%****ν**** scaled****	****	****38.4%****	****	****51.4%****	****	****58.0%**

**Maximum ****χ****2**** probability from fits to ****ν**** and ****ν ****excesses in 200-475 MeV range**

- Preliminary

- _

- _

- _

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Outline

** ****Motivation for  ****ν****e**** appearance search**
** ****MiniBooNE Experiment**
** ****MiniBooNE  ****ν****e**** analysis**
** ****Results **
- Oscillation fits
- Implications for low energy excess** **observed in neutrino mode
** ****Future prospects and conclusions**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Future MiniBooNE Analyses

**Combined ****ν****e**** and ****ν****e**** appearance analysis (with CP violation) for stronger constraints on oscillations**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Future MiniBooNE Analyses

**Combined ****ν****e**** and ****ν****e**** appearance analysis (with CP violation) for stronger constraints on oscillations**
**Combined ****ν****e**** and ****ν****e**** analysis for low energy events with systematic correlations properly folded in, for testing various low energy excess interpretations**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Future MiniBooNE Analyses

**Combined ****ν****e**** and ****ν****e**** appearance analysis (with CP violation) for stronger constraints on oscillations**
**Combined ****ν****e**** and ****ν****e**** analysis for low energy events with systematic correlations properly folded in, for testing various low energy excess interpretations**
**Combined MiniBooNE-NuMI ****ν****e**** ****appearance analysis**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Conclusion

**We have performed a ****blind analysis**** to **** ****ν****μ******** ****ν****e**** ****oscillations:****ν****e**** ****data in agreement with MonteCarlo background prediction as a function of E****ν****QE****. **

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Conclusion

**So far, ****no strong evidence for oscillations**** in antineutrino mode (although currently ****limited by statistics****). **

**(3.386e20 POT)**

**Joint KARMEN + ****LSND 90%CL ****allowed region**

**MB limit**

**MB limit**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Conclusion

**3.****	****Interestingly, ****no evidence of significant excess**** at low energy in antineutrino mode. This has already placed constraints to various suggested low energy excess interpretations.**

**	****	****Stat Only****	****Correlated Syst****	****Uncorrelated Syst**
**Same ****ν****,****ν ****NC  ****	****0.1%****	****	****0.1%****	****	****6.7%****NC ****π****0**** scaled****	****3.6%****	****	****6.4%****	****	****21.5%****POT scaled****	****0.0%****	****	****0.0%****	****	****1.8%****Bkgd scaled****	****2.7%****	****	****4.7%****	****	****19.2%****CC scaled****	****2.9%****	****	****5.2%****	****	****19.9%****Low-E Kaons****	****0.1%****	****	****0.1%****	****	****5.9%****ν**** scaled****	****	****38.4%****	****	****51.4%****	****	****58.0%**

- Preliminary

- _

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Conclusion

**4.****	****In process of ****collecting more data**** aiming for a total of 5.0e20 POT. This will improve sensitivity to oscillations, and allow further investigation of low energy excess.**

**Joint KARMEN + LSND 90%CL allowed region**

- Preliminary

**Projected MiniBooNE****90% CL sensitivity ****for 5.0e20 POT**

- Preliminary

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Thank you!

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Backup slides

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## 2-subevent structure of νμ CCQE events

- 2-subevent structure of νμ CCQE events

**Multiple hits within a ~100 ns**
**window form “subevents”**

- from stopped
- μ  e νμ νe

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MA, κ fits

**Q****2**** shape-only fit using ****ν****μ**** CCQE sample:**
** ****higher axial form factor (M****A****)**
** ****new nuclear effect parameter, ****κ****, introduced ****	****to model Pauli suppression or other effects at low Q****2**
**[Phys. Rev. Lett. 100, 032301 (2008).]**
**ν ****mode: **
**M****A**** = 1.23 ****± 0.20 GeV**
**κ**** = 1.019 ****± 0.011**
***Q******2****** = -m******μ******2****** + 2 E******ν****** ******( E******μ****** ******– p******μ****** ******cos******θ******μ****** ******)***

- MA, κ fits

**ν****μ**** CCQE sample in ****neutrino mode**

**world M****A**

**MC after tuning**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MA, κ fits

**Q****2**** shape-only fit using ****ν****μ**** CCQE sample:**
** ****higher axial form factor (M****A****)**
** ****new nuclear effect parameter, ****κ****, introduced ****	****to model Pauli suppression or other effects at low Q****2**
**[Phys. Rev. Lett. 100, 032301 (2008).]**
**ν ****mode (apply M****A****, ****κ****, from ****ν**** mode): **
**M****A**** = 1.23 ****± 0.20 GeV**
**κ**** = 1.019 ****± 0.011**
***Q******2****** = -m******μ******2****** + 2 E******ν****** ******( E******μ****** ******– p******μ****** ******cos******θ******μ****** ******)***

- MA, κ fits

** ****ν****μ**** CCQE sample in ****antineutrino mode**

- _

- _

**good agreement with data**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MA, κ fits

- MA, κ fits

** ****ν****μ**** CCQE sample in ****antineutrino mode**

- _

**Also good agreement in other kinematic variables**

**ν ****mode (apply M****A****, ****κ****, from ****ν**** mode): **
**M****A**** = 1.23 ****± 0.20 GeV**
**κ**** = 1.019 ****± 0.011**

- _

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Wrong-Sign (WS) measurement in antineutrino mode

**Bigger fraction of wrong signs in antineutrino running than in neutrino running**
**Need to determine the fraction of ν****μ**** (wrong sign component), as opposed to ****ν****μ****, in the beam**
****** ****use angular distribution of outgoing   muons**

- _

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## NC π0 fits in antineutrino mode

- NC π0 fits in antineutrino mode

**Sample of ~2700 events after cuts**
**first measurement at 1 GeV**

**NC π****0**** measurement ******
**constrains misidentified ν****e**** like ****events:**
**	****– ****π****0**** background**
**	****– ****Δ**** radiative decay**

- _

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Rejection of “dirt” events (background)

**Dirt backgrounds tend to come from gamma that sneak through the veto and convert in the tank **
**	******** ****pile up at high radius**
**They don't carry full ****ν**** energy **
**	******** ****pile up at low visible energy**
**Apply ****R-to-wall**** vs. ****E****visible**** (2D) cut:**
**(distance back to wall along ****reconstructed track)**
**Rejects ~80% of dirt backgrounds**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Absorber studies

**3.386e20 POT**
**0 absorber: 2.205e20 POT**
**1 absorber: 0.569e20 POT**
**2 absorber: 0.612e20 POT**

**consistency between absorber periods**
**absorber: ****	****0 ****	****1 ****	****2**
**absPOT (e20): ****	****2.205 ****	****0.569 ****	****0.612**
**ν****e**** obs. events**
**     ****absPOT**

**=  x ****	****    0.66x ****	****    0.61x**

**_**

**(stat-only errors shown)**
**Events rates in 3 absorber periods ****consistent with each-other**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Fit method

**The following three distinct samples are used in the oscillation fits, obtained using the same selection requirements used in neutrino mode analysis:**
**Background** to νe oscillations
**ν****e**** Signal** prediction (dependent on Δm2, sin22θ)
**ν****μ**** CCQE** sample, used to constrain νe prediction (signal+background)

- ―

- ―

**signal**

**bkgd**

**ν****μ**** ****CCQE**

**signal**

**bkgd**

**ν****μ**** ****CCQE**

**Syst+stat block-3x3 covariance matrix in E****ν****QE**** bins**
**( in units of events****2 ****) for all 3 samples**

- ―

- ―

- ―

- ―

**collapsed to block-2x2 matrix (****ν****e**** and **** ****ν****μ**** CCQE)****for ****χ****2**** calculation**

- _

- _

**Matrix is actually 53x53 (in E****ν****QE**** bins) !**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Need a direct test of LSNDand another handle on the low energy excess

**Joint KARMEN + LSND 90%CL allowed region**

- Need a direct test of LSNDand another handle on the low energy excess

**MiniBooNE ****90% CL sensitivity**
**to ****ν****μ********ν****e**** oscillations**

-  _

-  _

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE sensitivity to νμ→ νe

- MiniBooNE sensitivity to νμ→ νe

**MiniBooNE sensitivity for ****3.386E20 POT**

- ―

- ―

**3.386e20 POT**
**MB sensitivities for ****TBA and BDT**
**Overlaid on joint ****KARMEN+LSND****90% CL allowed****region **

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## 10e20?

**MiniBooNE will be collecting antineutrino data until June 15****th**** (scheduled shutdown), with a goal of collecting data for a total of 5.0e20 POT.**
**(Current POT projections estimate a total of 5.3e20 POT will be delivered by that point)**

**MiniBooNE TBA sensitivity**
**E****ν****QE****>200MeV **

**Relatively small gain in sensitivity for**** 5e20POT**** to ****10e20POT ****to justify extra running**

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Results: Fits to EνQE > 200 MeV

**2D global fit (iterative):**** **

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## Results: Fits to EνQE > 475 MeV

**2D global fit (iterative):**** **

- Results: Fits to EνQE > 475 MeV

- Consistent with fits to EνQE > 200 MeV

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE limit to νμ νe oscillations

**1-sided raster limit:**** **

**MB E****ν****QE**** >200MeV limit**
**(3.386e20 POT)**

**No strong evidence for ****oscillations ******

- G. Karagiorgi

- 12/11/2008 FNAL W&C

## MiniBooNE limit to νμ νe oscillations

- MiniBooNE limit to νμ νe oscillations

**1-sided raster limit:**** **

**MB E****ν****QE**** >475MeV limit**
**(3.386e20 POT)**

**No strong evidence for ****oscillations ******

- G. Karagiorgi

- 12/11/2008 FNAL W&C