# Presentation: 778594

## MiniBooNE  and  disappearance results 

- Kendall Mahn
- Columbia University

- K. Mahn

- 10/31/08 W&C

## Overview

- Neutrino oscillation
- MiniBooNE experiment
- MiniBooNE-only neutrino disappearance analysis
- Antineutrino disappearance analysis
- Improvements to disappearance analysis
- Conclusion

- K. Mahn

- 10/31/08 W&C

## Overview

- Neutrino oscillation
- MiniBooNE experiment
- MiniBooNE-only neutrino disappearance analysis
- Antineutrino disappearance analysis
- Improvements to disappearance analysis
- Conclusion

- K. Mahn

- 10/31/08 W&C

## Neutrino oscillation

- Since there are three observed flavors of neutrinos (e, , ), the mixing
- matrix, Ui , contains three mixing angles (12,23, 13) and a CP violating
- phase  It can be factorized into three blocks, each corresponding to
- two neutrino mixing.
- cij= cosij, sij= sinij

- K. Mahn

- 10/31/08 W&C

## Neutrino oscillation

- The probability to observe  with a pure  sample is:
- where L (km) is the distance traveled, E (GeV) is the energy of the
- neutrino and m2 (eV2) is the difference of the masses squared:
- Choice of L and E chooses what range of m2 the experiment is
- sensitive to, the size of the oscillations sets sin22

- K. Mahn

- 10/31/08 W&C

## Disappearance and Appearance experiments

- Appearance experiment		            Disappearance experiment
- Detect more  than expected                 Detect less  than expected

- Neutrinos at energy E1 oscillate differently than at E2 for the same L,
- creating a unique signature for oscillation vs energy

- K. Mahn

- 10/31/08 W&C

## Reducing errors with a second detector

- Adding a second detector measures the flux x cross section to the level
- of uncorrelated errors between the two detectors
- 	Start with 20% error
- 	Remove flux, cross section, and beam errors: 20%   4%
- 	Add 5% uncorrelated errors: 4% + 5% = 6%

| Source of error | Total fractional error  (%) |
| --- | --- |
| pBe  + production (flux) | 4.0 |
| beamline and horn model (flux) | 4.3 |
| cross sections | 18.6 |
| detector model | 4.0 |
| total | 19.9 |

- K. Mahn

- 10/31/08 W&C

## Normalization information

- 1)  Normalization information:
- Compare total number of events to expectation
-  (aka “counting experiment”)
- K2K expected: 158 + 9.2 - 8.6 events at the far detector
- but observed: 112 events
- Normalization information provided by additional detectors
- Limited by statistics at far detector

- K. Mahn

- 10/31/08 W&C

## Shape information

- 2) Shape information:
- Compare the energy distribution of events to no oscillation hypothesis

- Ratio of oscillated events/ unoscillated events vs energy
-  m2 changes the periodicity of the oscillation (see m2=1eV2, m2=3 eV2)
-  sin22 changes the depth of the oscillation (see sin22=1.0, sin22=0.5)
- MiniBooNE will make a one detector
- shape measurement

- K. Mahn

- 10/31/08 W&C

## Oscillation observations

- “Atmospheric”: m223~10-3eV2,
- 			sin2223 ~45°
- 	With atmospheric : SuperK
- 	With Accelerator : MINOS
- “Solar”: m212 ~10-5eV2, sin2212 ~32°
- 	With solar : SNO
- 	With reactor : KamLAND
- “High m2”: m2~1-10eV2
- 	CDHS (disappearance)
- 	CCFR (disappearance)
- 	 LSND (appearance)

- Atmospheric

- Solar

- High m2

- K. Mahn

- 10/31/08 W&C

## High m2 disappearance expts

- CCFR (FNAL E701)
- I.E. Stockdale et al Z.Phys.C27:53,1985
- Mono energetic meson beam  produces dichromatic (~50, 160GeV) neutrino beam
- Two steel/scintillator  detectors  at 715m and 1116m

- CDHS at CERN
- F. Dydak et al. Phys.Lett.B134:281,1984.
-  19.2 GeV protons on Be target  produces ~3GeV neutrino beam
- Two iron/scintillator detectors at 130m and 885m

- 90% CL excluded region CCFR
- 90% CL excluded region CDHS

- K. Mahn

- 10/31/08 W&C

## LSND e appearance

- LSND experiment
- Observation of 3.8  excess of e in  beam
- Karmen, Bugey and
- MiniBooNE exclude the
- LSND parameter space
- If e oscillate but e do
- not, then exotic physics is
- needed to explain this signal

- K. Mahn

- 10/31/08 W&C

## Sterile neutrinos

- One explanation for  the LSND oscillation signal is to add another
- “sterile” flavor of neutrino (or 2 or N) to the mixing matrix:
- Adding 1 sterile neutrino is 3+1, adding N is 3+N

- Disappearance expts (CDHS/CCFR/atmospheric)
- disfavor 3+1 already
- Maltoni, Schwetz, Valle,  Phys.Lett.B518:252-260,2001. hep-ph/0107150
- 3+2 models have large mixing and prefer the
- region where experimental limits are weakest G. Karagiorgi et al, Phys.Rev.D75:013011,2007. hep-ph/0609177

- K. Mahn

- 10/31/08 W&C

## Motivation for neutrino disappearance

- The observation of  disappearance could imply:
- 	- sterile neutrinos G. Karagiorgi et al, Phys.Rev.D75:013011,2007. hep-ph/0609177
- 	- neutrino decay Palomares-Ruiz, Pascoli, Schwetz, JHEP 0509:048,2005. hep-ph/0505216
- 	- extra dimensions  Pas, Pakvasa, Weiler, Phys.Rev.D72:095017,2005. hep-ph/0504096
- The lack of  disappearance also can constrain these models

- Resonant E~40MeV

- When the path-length increases for active neutrinos in the bulk relative to sterile
- neutrinos, oscillations between sterile and
- active flavors are enhanced above a
- resonant energy, and suppressed below
- A resonance energy between 30-400MeV
- explains all data in a 3+1 model

- K. Mahn

- 10/31/08 W&C

## Motivation for neutrino disappearance

-  If  disappear, but  do not would signal CPT violation
-  Sterile neutrino models (3+1 or 3+2) can be CPT violating
- 	Barger, Marfatia, & Whisnant, Phys. Lett. B576 (2003) 303
-  Introduction of a new light gauge boson
- 	Nelson, Walsh Phys .Rev. D77 033001 (2008) hep-ph/0711.1363
-  Lorentz violation
- 	Katori, Kostelecky, & Tayloe,  Phys. Rev. D74 (2006) 1050009
-     P. Adamson et al, Phys. Rev. Lett. 101 151601 (2008) hep-ex/0806.4945

- K. Mahn

- 10/31/08 W&C

## Motivation for neutrino disappearance

- The lack of  disappearance constrains new physics models
- The combination of  and  disappearance tests unitarity and CPT

- Can MiniBooNE add to the current disappearance limits?
- YES! with both neutrinos and antineutrinos

- K. Mahn

- 10/31/08 W&C

## Overview

- Neutrino oscillation
- MiniBooNE experiment
- MiniBooNE-only neutrino disappearance analysis
- Antineutrino disappearance analysis
- Improvements to disappearance analysis
- Conclusion

- K. Mahn

- 10/31/08 W&C

## The MiniBooNE Collaboration

-             ***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
-   ***University of Florida***
-  G.T.Garvey, A.Green, C.Green, W.C.Louis, G.McGregor, G.B.Mills, V.Sandberg, R.Schirato,
-  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***

- Collaboration may be larger than it appears

- K. Mahn

- 10/31/08 W&C

## MiniBooNE Experiment

- 8.9 GeV/c protons on Be produce mesons which decay to neutrinos or
- antineutrinos
- Changing the polarity of the horn focuses positive (negative) mesons
- and produces a neutrino (antineutrino) beam
- Data sets shown today are:
- 			5.579e20POT neutrino mode (190,454 events)
- 			3.386e20POT antineutrino mode (27,053 events)

- K. Mahn

- 10/31/08 W&C

## MiniBooNE Experiment

- 8.9 GeV/c protons on Be produce mesons which decay to neutrinos or
- antineutrinos
- In 2007, the SciBooNE detectors were put into the beamline at 100m

- SciBooNE

- K. Mahn

- 10/31/08 W&C

## Beamline Timeline

- 1/06-10/07: First antineutrino run period
- 	5/29/07: SciBooNE begins data taking
- 10/07-4/08: Joint neutrino run with SciBooNE
- 4/08-now: Joint antineutrino run with SciBooNE
- 	8/08: SciBooNE decommissioned
- In MiniBooNE:  ~1  per 1e15 POT
- 			~ 0.2  per 1e15 POT
- In SciBooNE: ~5x closer, ~50x smaller
- 			 ~0.5  per 1e15 POT
- 			~ 0.1   per 1e15 POT

- Thank you Accelerator division!
-  from SciBooNE & MiniBooNE

- K. Mahn

- 10/31/08 W&C

## MiniBooNE Detector

- 	12 m diameter, 1280 inner PMTs, 240 outer ‘veto’ PMTs
- Use hit topology and timing to
- determine electron-like or muon-like
- Cherenkov rings and corresponding
- charged current neutrino interactions

- e-

- -

- e

- 

- W+

- W+

- K. Mahn

- 10/31/08 W&C

## e sample is consistent with expectation >475 MeV (0.6  excess) 
3.0  excess at low energy (200-475 MeV)
Initial observation confirmed with later work (Aug 1st W&C)
Excess cannot be described based on a simple 2  mixing hypothesis
PRL forthcoming

This result assumes no  disappearance

- 3.0  excess at low energy (200-475 MeV)
- Initial observation confirmed with later work (Aug 1st W&C)
- Excess cannot be described based on a simple 2  mixing hypothesis
- PRL forthcoming
- This result assumes no  disappearance

- MiniBooNE e appearance results

- K. Mahn

- 10/31/08 W&C

## Overview

- Neutrino oscillation
- MiniBooNE experiment
- MiniBooNE-only neutrino disappearance analysis
- Antineutrino disappearance analysis
- Improvements to disappearance analysis
- Conclusion

- K. Mahn

- 10/31/08 W&C

## To do a  disappearance analysis with one detector, we need:

Event selection 
+
Prediction with systematic errors
flux, cross section, detector effects
+ 
Disappearance fit machinery

- Event selection
- +
- Prediction with systematic errors
- flux, cross section, detector effects
- +
- Disappearance fit machinery

-  disappearance analysis plan

- K. Mahn

- 10/31/08 W&C

## Use Charged Current Quasi elastic events (CCQE)  events 
Selecting on muon selects 
With just muon’s energy, angle, can reconstruct neutrino energy

- Selecting on muon selects 
- With just muon’s energy, angle, can reconstruct neutrino energy

-  disappearance sample

- W+

- CCQE 

- -

- 

- p

- n

**e**

****

- 

- 12C

- p

- n

- Tag single muon events and their decay electron
-  2 subevents (****, then e) with minimal veto activity in both
-  muon-like track, 2nd event below decay electron energy endpoint
-  both events within fiducial volume

- “Selecting muons in a Cherenkov detector is like shooting fish in a barrel”
- - Aunt Edith

- K. Mahn

- 10/31/08 W&C

## Impressive neutrino sample: ~200k events, 74% CCQE purity

Background is CC+ where the pion is absorbed in the nucleus or detector
All events can oscillate, but misreconstruction of CC+ as CCQE events mean CC+ are shifted to low EQE
Pure neutrino sample, only 1.4% antineutrino content

- Impressive neutrino sample: ~200k events, 74% CCQE purity
- Background is CC+ where the pion is absorbed in the nucleus or detector
- All events can oscillate, but misreconstruction of CC+ as CCQE events mean CC+ are shifted to low EQE
- Pure neutrino sample, only 1.4% antineutrino content

- CCQE  selection

- W+

- CCQE 

- -

- 

- p

- n

- W+

- CC+ 

- -

- 

- p

- n

- 

- K. Mahn

- 10/31/08 W&C

## To do a  disappearance analysis with one detector, we need:

Event selection 
+
Prediction with systematic errors
flux, cross section, detector effects
+ 
Disappearance fit machinery

- Event selection
- +
- Prediction with systematic errors
- flux, cross section, detector effects
- +
- Disappearance fit machinery

-  disappearance analysis plan

- K. Mahn

- 10/31/08 W&C

## Flux prediction

- Neutrino beamline is modeled in Geant4 hep-ex/0806.1449
- 	p + Be target  meson production  focusing  decay  neutrinos
- Included as systematic error:
- Beam optics and targeting efficiency
- p+Be elastic and inelastic cross sections
- Production of mesons (+/-, K+/-) from pBe interactions
- Horn magnetic field
- Largest sources of error are meson production and horn magnetic field

## Meson Production Uncertainties

- The HARP experiment measured p+Be +/ - (hep-ex/0702024)
- Use the HARP data and errors to produce different fluxes consistent with HARP
- Propagate the new fluxes through to the neutrino spectrum and look at the effect on the CCQE sample
- 88% of the CCQE   sample is within HARP’s coverage;  99% is contained within HARP and  > 0.210

- p pi

- HARP data with errors in  bins
- MiniBooNE flux parameterization

- p(GeV)

- ddpd (mb c/[GeV sr])

## Cross section model and the disappearance result

- For e appearance result, we tuned the cross section model
- Shape only fit in Q2 using the CCQE  sample favored a higher axial form factor (MA) and a new nuclear effect parameter, K, was introduced to model Pauli suppression or other effects at low Q2
- Phys. Rev. Lett. 100, 032301 (2008).
- MA = 1.23 +/- 0.20 GeV
- K = 1.019 +/- 0.011

## Cross section model and the disappearance result

- For  disappearance, we undo the tuning and set the uncertainties to cover the excursion in the world data and our own
- 	World’s data on deuterium: MA=1.014 +/- 0.014 GeV
- 	Bodek et al J.Phys.Conf.Ser.110:082004,2008. hep-ex/0709.3538
- 	K2K CCQE  on Carbon: MA = 1.14+/- 0.11 GeV
- 	F. Sanchez, NuInt07
- 	 K2K CCQE  on Oxygen MA = 1.20+/- 0.12 GeV
- 	R. Gran et al., PRD74, 052002 (2006)
- 	Using: MA=1.0 +/-0.23 GeV, K=1.000+/- 0.0220
- The cross section uncertainties also include uncertainties on the CC+ cross section and pion charge exchange and absorption in the nucleus

## Can the cross section model mask disappearance?

- (MA=1.2 GeV,K=1.02) / (MA =1.0 GeV, K=1.0) induces a shape change
- similar to m2=0.5 eV2 in EQE
- But  in Q2, oscillations vanish while the effect of the cross sections
- is stronger

- Q2 (GeV2)

- EQE (GeV)

- Preliminary

- Preliminary

## Detector uncertainties

- Muon hodoscope tracked incoming (10kHz) cosmic ray muons entering detector
- Events which stopped in scintillation cubes provided known distance
- with which to calibrate muon energy in oil

- Muon kinetic energy resolution is 7% at 300MeV
- Angular resolution is 5°

## Systematic error summary

| Source of error | Total fractional error  (%)
(counting experiment) |
| --- | --- |
| pBe  + production (flux) | 4.0 |
| beamline and horn model | 4.3 |
| cross sections | 18.6 |
| detector model | 4.0 |
| total | 19.9 |

- Data = 190,454 events
- MC (MA,K=1.0) = 145,085 +/- 20%
-   The more one under predicts the data, the stronger the sensitivity to   disappearance becomes
-   We under predict the data normalization by 1.5 
-   In order to be conservative, we choose to perform a shape only disappearance fit
-   Normalization information will be included with SciBooNE

## To do a  disappearance analysis with one detector, we need:

Event selection 
+
Prediction with systematic errors
flux, cross section, detector effects
+ 
Disappearance fit machinery

- Event selection
- +
- Prediction with systematic errors
- flux, cross section, detector effects
- +
- Disappearance fit machinery

-  disappearance analysis plan

- K. Mahn

- 10/31/08 W&C

## Shape-only disappearance fit

- Use Shape only Pearson’s :
- For each point in oscillation space compare the prediction,
- pi(m2, sin2), to the data, di, and sum over bins i and j

-  Mij is shape only (variations conserve events across all bins)
-  X(m2, sin2)  renormalizes pi  to the total data events,

- For m2, sin2 points where  >  (CL), draw that CL curve
- For 16 bins, (90% CL) = 23.5

## Sensitivity 

- The sensitivity is a fit to fake
- data which exactly agrees with
- prediction but all statistical and
- systematic uncertainties are
- included
- A shape-only, single detector
- measurement is sensitive to 
- disappearance in the particular
- region favored by 3+2 models

- Sensitivity

- Preliminary

- shape-only sensitivity
- for 90%CL,3 and 5

- K. Mahn

- 10/31/08 W&C

## Cross check: Frequentist 2

- For each point, create 50 “fake experiments” using fluctuations consistent with
- the errors and calculate 2 ( m2, sin2CL
- For fit to real data, use 2 ( m2, sin2CL) to generate CL curves
- 	Fit data at each point as if it corresponds to that true
- point, calculate 2
- 		if 2 > 2 ( m2, sin2CL for a given CL, draw curve
- Procedure can be done with shape-only fits like Pearson’s 2
- 	Renormalize pi at each point, matrix is shape only

- Cross check: Frequentist 2

- K. Mahn

- 10/31/08 W&C

## Cross check: Frequentist 2

- by mapping out distorted 2 surface
- but is computing intensive
- 2 ranges from ~4 degrees of freedom (dof) at low sin2 to 1dof at high sin2
- Approximately 1 hour of computing for each 2 point shown, as compared to the ~1 minute needed for the Pearson’s  limit

- Cross check: Frequentist 2

- Shape-only Pearson’s  limit
- to a mock data set
- 2 limit to the
- same mock
- data set

- K. Mahn

- 10/31/08 W&C

## Why does the limit look weird?

- can shift rapidly across sin2
- 	 We have been calling them “wiggles”
- Wiggles are less pronounced in the
- sensitivity, but are present for any fake
-  or real data fit

- Chi2

- Shape-only Pearson’s  limit
- to a mock data set
- 2 limit to the
- same mock
- data set

- K. Mahn

- 10/31/08 W&C

## What are the wiggles?

- For a fixed sin2, m2 close in value
- do not have similar behavior in
- EQE
- For sin2=0.1, if we compare the
- shape of m2=2 eV2 to
- m2=3 eV2 we see that the
- 2(m2=2) < 2(m2=3)
- The 2 changes with m2;
- a flat cut on 2 creates wiggles
- This problem is exacerbated for data
- fluctuations and can occur for any error envelope

- Chi2

- Preliminary

- 	EQE (GeV)

- K. Mahn

- 10/31/08 W&C

## What are the wiggles?

- CDHS, linear scale,
- two detectors

- Bugey, log scale,
- two positions, 1 detector

- CCFR, linear scale,
- two detectors

- This effect shows up in previous disappearance results even when
- there is a second detector
- 	A second detector makes it harder to match L/E across all L, E but anytime it can, the 2 will be lower than nearby m2

- K. Mahn

- 10/31/08 W&C

## To do a  disappearance analysis with one detector, we need:

Event selection 
+
Prediction with systematic errors
flux, cross section, detector effects
+ 
Disappearance fit machinery
=
Candy! 
er, Results!

- Event selection
- +
- Prediction with systematic errors
- flux, cross section, detector effects
- +
- Disappearance fit machinery
- =
- Candy!
- er, Results!

-  disappearance analysis plan

- K. Mahn

- 10/31/08 W&C

## Data and null oscillation prediction

- Data (5.579e20POT,statistical errors shown) with null oscillation prediction
- (normalized to total data) vs EQE
- Errors shown are diagonal elements of the shape-only error matrix
- 2(null) =17.78 (34% for 16 bins)
- Systematics dominate:
- 2(null, statistics only)=665

- Preliminary

- K. Mahn

- 10/31/08 W&C

## Neutrino disappearance limit

- for 90%CL,3 and 5
- 2 (null) =17.78 (34%,16 bins)
- 2 (min) =12.72 (69%, 16bins)
- at m2=17.5eV2,sin2=0.16

- MiniBooNE observes
- no neutrino disappearance

- Preliminary

- K. Mahn

- 10/31/08 W&C

## Neutrino disappearance limit

- Preliminary

- data limit
- for 90%CL,3 5

- sensitivity
- for 90%CL,3 5

- PRELIMINARY

- PRELIMINARY

- K. Mahn

- 10/31/08 W&C

## Overview

- Neutrino oscillation
- MiniBooNE experiment
- MiniBooNE-only neutrino disappearance analysis
- Antineutrino disappearance analysis
- Improvements to disappearance analysis
- Conclusion

- K. Mahn

- 10/31/08 W&C

## Ability to change polarity of horn allows us to focus negative mesons and produce an antineutrino beam
Apply same CCQE selection cuts, same error analysis, same fit machinery
Main difference:Substantial neutrino events in the antineutrino sample (25%)

- Apply same CCQE selection cuts, same error analysis, same fit machinery
- Main difference:Substantial neutrino events in the antineutrino sample (25%)

- Antineutrino CCQE sample

- PRELIMINARY

- K. Mahn

- 10/31/08 W&C

## Is there a shape difference
between the neutrino background
and the antineutrino signal?

The neutrino and antineutrino 
spectrums are quite similar

If we change the normalization
of the antineutrinos (N-)
differently from the neutrinos
(N+), the effect on the shape of 
the antineutrino sample is less
than the size of the statistical
errors

- between the neutrino background
- and the antineutrino signal?
- The neutrino and antineutrino
- spectrums are quite similar
- If we change the normalization
- of the antineutrinos (N-)
- differently from the neutrinos
- (N+), the effect on the shape of
- the antineutrino sample is less
- than the size of the statistical
- errors

- Neutrinos in antineutrino sample

- Ratio of N+=0.8, N-=1.2 to
- N+/-=1.0 vs EQE

- K. Mahn

- 10/31/08 W&C

## 90% CL antineutrino disappearance sensitivity for 3.38E20 POT
Plot assumes no   disappearance based on prior work
Substantial new parameter space covered!

- Plot assumes no   disappearance based on prior work
- Substantial new parameter space covered!

- Antineutrino disappearance sensitivity

- PRELIMINARY

- K. Mahn

- 10/31/08 W&C

## Second dose of sugar for the day:
antineutrino disappearance results

- antineutrino disappearance results

- Antineutrino results!

- K. Mahn

- 10/31/08 W&C

## 3.38e20 dataset w/ statistical errors
null oscillation w/ diagonal shape errors
2(null) = 10.29 (85% for 16dof)
2(null, stat only) = 109 (16dof)

- 3.38e20 dataset w/ statistical errors
- null oscillation w/ diagonal shape errors
- 2(null) = 10.29 (85% for 16dof)
- 2(null, stat only) = 109 (16dof)

- PRELIMINARY

- Antineutrino disappearance results

- 2(min) = 5.43 (99.5%
- for 16dof) at
- m2=31.3eV2,sin2=0.96

- No antineutrino
- disappearance
- observed

- PRELIMINARY

- K. Mahn

- 10/31/08 W&C

## Antineutrino disappearance results

- PRELIMINARY

- PRELIMINARY

- sensitivity
- for 90%CL,3 5

- data limit
- for 90%CL,3 5

- K. Mahn

- 10/31/08 W&C

## Overview

- Neutrino oscillation
- MiniBooNE experiment
- MiniBooNE-only neutrino disappearance analysis
- Antineutrino disappearance analysis
- Improvements to disappearance analysis
- Conclusion

- K. Mahn

- 10/31/08 W&C

## Improvements to  disappearance?

- one at a time, which error
- affects 90% shape only
- sensitivity most?
- Dominant errors are flux and
- cross section
- Near detector constrains both
- Incorporate SciBooNE data!

- Improvements to  disappearance?

- K. Mahn

- 10/31/08 W&C

## Insert preexisting fine grained tracking detectors into Booster Neutrino Beamline 
Provide cross section information for future oscillation experiments, such as T2K
Similar energy range
Also provides a near detector for MiniBooNE
Nearly identical flux, identical target (carbon)

- Provide cross section information for future oscillation experiments, such as T2K
- Similar energy range
- Also provides a near detector for MiniBooNE
- Nearly identical flux, identical target (carbon)

**50 m**

**MiniBooNE Detector**

**SciBooNE**

**Booster **ν** beam**

**100 m**

**440 m**

- SciBooNE

- K. Mahn

- 10/31/08 W&C

## The SciBooNE collaboration

- K. Mahn

- 10/31/08 W&C

## SciBar vertex detector
14,336 channel extruded scintillator with WLS fibers
Can use dE/dX to distinguish
	protons from pions, muons
tracks >8cm are reconstructable
Electron Calorimeter (EC)
2 plane “spaghetti” calorimeter (scintillating fiber & lead foil)
11X0, 14% √E
Muon range detector (MRD)
362 scintillator counters, 13 alternating vertical/horizontal planes interspersed with iron
Measures muons < 1.2 GeV
	to ~10% resolution

- 14,336 channel extruded scintillator with WLS fibers
- Can use dE/dX to distinguish
- 	protons from pions, muons
- tracks >8cm are reconstructable
- Electron Calorimeter (EC)
- 2 plane “spaghetti” calorimeter (scintillating fiber & lead foil)
- 11X0, 14% √E
- Muon range detector (MRD)
- 362 scintillator counters, 13 alternating vertical/horizontal planes interspersed with iron
- Measures muons < 1.2 GeV
- 	to ~10% resolution

- W+

- CCQE 

- -

- 

- -

- p

- n

**p**

- SciBooNE detectors

****

- Real CCQE candidates

****

- MRD

- SciBar

- SciBar

- EC

- 

- 

- 

**p**

**p**

- K. Mahn

- 10/31/08 W&C

## Tag CCQE events within SciBar using decay electron
	“SciBar contained”
Tag CC events with muon in MRD
	MRD Matched  “MRD Stopped” or “MRD Penetrated”

- -

- Tag CCQE events within SciBar using decay electron
- 	“SciBar contained”
- Tag CC events with muon in MRD
- 	MRD Matched  “MRD Stopped” or “MRD Penetrated”

- SciBooNE data samples

- “MRD Stopped” sample

- -

- -

- e-

- Preliminary

- EQE

-  Already developing data sets
- neutrino mode: 0.99e20 POT
- 	~30k MRD Matched events
- antineutrino mode:1.53e20 POT
- 	~13k MRD Matched events

- K. Mahn

- 10/31/08 W&C

## Fit will be able to include normalization information from SciBooNE
	For some oscillation signals, oscillation can be seen in SciBooNE
The flux and cross section will cancel, but the amount of correlation between
the two detectors is reduced by statistics and detector errors

- 	For some oscillation signals, oscillation can be seen in SciBooNE
- The flux and cross section will cancel, but the amount of correlation between
- the two detectors is reduced by statistics and detector errors

- Joint MiniBooNE/SciBooNE analysis

- Oscillation at MiniBooNE (500m)

- Oscillation at SciBooNE (100m)

- K. Mahn

- 10/31/08 W&C

## MiniBooNE observes no neutrino or antineutrino disappearance
Will add constraints to 3+N models
Limits CPT violating models

Future work will include SciBooNE as a near detector constraint on the disappearance analysis 

 Additional BooNE news:
SciBooNE has finished its first result on CC+ coherent production
	November 20th Wine and Cheese
A host of MiniBooNE cross section analyses are also in the works
CC+/CCQE ratio measurement
NC 0 coherent/resonant fraction for antineutrino events
Differential cross sections (CCQE, NC elastic, NC0, CC+, CC0)
It’s a treat not a trick: December Wine and Cheese with electron
 antineutrino appearance results!

- Will add constraints to 3+N models
- Limits CPT violating models
- Future work will include SciBooNE as a near detector constraint on the disappearance analysis
-  Additional BooNE news:
- SciBooNE has finished its first result on CC+ coherent production
- 	November 20th Wine and Cheese
- A host of MiniBooNE cross section analyses are also in the works
- CC+/CCQE ratio measurement
- NC 0 coherent/resonant fraction for antineutrino events
- Differential cross sections (CCQE, NC elastic, NC0, CC+, CC0)
- It’s a treat not a trick: December Wine and Cheese with electron
-  antineutrino appearance results!

- Conclusion

- K. Mahn

- 10/31/08 W&C