Mini Mini

OverviewOverview

Peter KasperPeter Kasper

NBI 2002NBI 2002

The MiniBooNE CollaborationThe MiniBooNE Collaboration

University of Alabama, TuscaloosaUniversity of Alabama, Tuscaloosa

Bucknell University, LewisburgBucknell University, Lewisburg

University of California, RiversideUniversity of California, Riverside

University of Cincinnati, CincinnatiUniversity of Cincinnati, Cincinnati

University of Colorado, BoulderUniversity of Colorado, Boulder

Columbia University, Nevis Labs, IrvingtonColumbia University, Nevis Labs, Irvington

Embry Riddle Aeronautical UniversityEmbry Riddle Aeronautical University

Fermi National Accelerator LaboratoryFermi National Accelerator Laboratory

Indiana University, BloomingtonIndiana University, Bloomington

Los Alamos National LaboratoryLos Alamos National Laboratory

Louisiana State University, Baton RougeLouisiana State University, Baton Rouge

University of Michigan, Ann ArborUniversity of Michigan, Ann Arbor

Princeton University, PrincetonPrinceton University, Princeton

MiniBooNE GoalsMiniBooNE Goals

• MiniBooNE’sMiniBooNE’s primaryprimary goal is to unequivocally confirm goal is to unequivocally confirm or refute the or refute the LSNDLSND oscillation signal for oscillation signal for ee

• Similar Similar L/E ~ 1L/E ~ 1 to LSND but to LSND but ~10x~10x higher energy higher energy

– EE ~ 0.5 - 1 GeV ~ 0.5 - 1 GeV

– L = 500 mL = 500 m

• Experimental signatures and backgrounds are Experimental signatures and backgrounds are completely different from LSNDcompletely different from LSND

– provides a truly provides a truly independentindependent test of their result. test of their result.

• If the signal is confirmed, a second detector will be If the signal is confirmed, a second detector will be built ...built ...

– i.e. full i.e. full BooNEBooNE

LSND and KARMEN ResultsLSND and KARMEN Results

• KARMEN limitsKARMEN limits

– Solid curveSolid curve calculated with calculated with the Feldman & the Feldman & Cousins Cousins approachapproach

– Dashed curveDashed curve is is experiment’s experiment’s sensitivitysensitivity

• LSND signal regionLSND signal region

– 90%90%

Lmax - L < 2.3Lmax - L < 2.3

– 99%99%

Lmax - L < 4.6Lmax - L < 4.6

The LSND SignalThe LSND Signal

• Signal Signal discrimination is discrimination is encapsulated into encapsulated into a variable a variable RR

– Ratio of Ratio of likelihood that likelihood that ee++ and and are are correlated to correlated to likelihood that likelihood that is accidental. is accidental.

• 87.9 ± 22.4 ± 6.0 87.9 ± 22.4 ± 6.0 event excess event excess consistent with consistent with e e pp e e++ n n followed followed by by nn pp d d ..

– 4 times the 4 times the expected rate expected rate

from beamfrom beamee `s`s

signal

LSND ImplicationsLSND Implications

• What we know from other experimentsWhat we know from other experiments

– Atmospheric Atmospheric ’s oscillate at ’s oscillate at mm22 ~ 10 ~ 10-3-3 with with maximal mixing ( e.g. SuperK )maximal mixing ( e.g. SuperK )

• favored favored

– Solar Solar ee’s oscillate at ’s oscillate at mm22 < 10 < 10-4-4 ( e.g. SNO ) ( e.g. SNO )

• ee favored favored

• LSND results has LSND results has mm22 ~ 10~ 10-1-1 for for ee

– hence require hence require 4 4 neutrino mass states neutrino mass states

• Only 3 active flavors ( LEP )Only 3 active flavors ( LEP )

– hence hence sterile sterile ’s’s are required are required

OROR

– neutrino masses neutrino masses antineutrino masses antineutrino masses

An Experimentally Allowed ModelAn Experimentally Allowed Model

• Bimaximal mixing in 3 + 1 models Bimaximal mixing in 3 + 1 models

– W. Krolikowski HEP-PH/0106350W. Krolikowski HEP-PH/0106350

– R.N.Mohapatra Phys.Rev. R.N.Mohapatra Phys.Rev. D64 D64 (2001) 091301,(2001) 091301,

m2 LSND

m2 Solar

m2 Atm.

e

s

An Alternative ModelAn Alternative Model

• Maximal CPT violation in Dirac mass termsMaximal CPT violation in Dirac mass terms– Barenboim, Borissov, Lykken & Smirnov Barenboim, Borissov, Lykken & Smirnov

HEP-PH/0108199HEP-PH/0108199

– Generates independent masses for Generates independent masses for ’s and’s and’s’s

– Motivated by branes with extra dimensionsMotivated by branes with extra dimensions

m2 LSND

m2 Solar

m2 Atm.

e

Proton BeamProton Beam

• MiniBooNE’s neutrino beam will be produced with a high MiniBooNE’s neutrino beam will be produced with a high intensity ( intensity ( 5E12 @ 5 Hz5E12 @ 5 Hz ) ) 8 GeV8 GeV proton beam from the proton beam from the Fermilab Fermilab BoosterBooster..

• The Booster cycles at The Booster cycles at 15 Hz15 Hz and produces and produces 1.6 1.6 secsec beam pulses. beam pulses.

New construction• Proton beam line• Target Hall• Decay pipe• Detector building

Beam LayoutBeam Layout

• Civil construction for the 8 GeV Beamline, Target Hall, and Decay Pipe began in June 2000.

50m long decay pipe

Beam Line ConstructionBeam Line Construction

• Civil Construction is complete and component installation is well Civil Construction is complete and component installation is well advanced. advanced. Ready for beam tests this April.Ready for beam tests this April.

24-Jan-02

Target Hall ConstructionTarget Hall Construction

• Civil and target pile construction is complete. Civil and target pile construction is complete. Horn Horn installation is scheduled to start in early May.installation is scheduled to start in early May.

24-Jan-02

24-Jan-02

Decay Pipe ConstructionDecay Pipe Construction

• Two absorbers at 25m (removable) and 50m (fixed) provide a cross check of the intrinsic e component in the beam.

13-Nov-00

50m absorber with muon counters

25m absorber

24-Jan-02

Air heat exchanger for cooling berm

The TargetThe Target

A A 65cm65cm, air cooled Be target will be inserted inside , air cooled Be target will be inserted inside a single focussing horna single focussing horn

Hadroproduction studies will be done for our energy and target. (BNL910 and HARP)

7-Feb-02

The HornThe Horn

• A single horn system will be used ( proposal had two )A single horn system will be used ( proposal had two )

• Less flux but also less background from high energy (>1 GeV) neutrinos than the original 2 horn designLess flux but also less background from high energy (>1 GeV) neutrinos than the original 2 horn design

• Horn has been built and tested for > 10Horn has been built and tested for > 1077 pulses pulses

20-Jun-01

The Neutrino BeamThe Neutrino Beam

• Intrinsic e contamination can be ..

– Inferred from events

– Simulated using hadroproduction measurements

– Measured using muon counters in and around the decay pipe

– Checked by comparing 50m and 25m absorber results

The DetectorThe Detector

• The detector is a The detector is a 40ft40ft ( (12.2m12.2m) diameter sphere filled ) diameter sphere filled with with 800 tons800 tons of pure mineral oil and instrumented with of pure mineral oil and instrumented with ~1500 8” ~1500 8” PMTs.PMTs.

• It is housed underground in order to provide some It is housed underground in order to provide some cosmic ray shielding.cosmic ray shielding.

The Detector (cont.)The Detector (cont.)

• It will consist two It will consist two optically separated optically separated regions ...regions ...

– An inner sphere with An inner sphere with 12801280 PMTs viewing a PMTs viewing a 445 ton445 ton fiducial fiducial volume ( volume ( 10%10% photocathode photocathode coverage)coverage)

– An outer veto shell An outer veto shell 35cm35cm thick thick monitored by monitored by 240240 PMTs.PMTs.

Detector StatusDetector Status

• The detector enclosure was completed in December 2000.The detector enclosure was completed in December 2000.

• The PMT installation was completed in October 2001.The PMT installation was completed in October 2001.

• Oil fill started early January and the detector is now 60% full.Oil fill started early January and the detector is now 60% full.

Detector Enclosure Jan 2001

PMT installation Sept. 2001

A Possible Stopping Cosmic Ray MuonA Possible Stopping Cosmic Ray Muon

Event ReconstructionEvent Reconstruction

• MiniBooNE will reconstruct quasi-elastic MiniBooNE will reconstruct quasi-elastic ee interactions by interactions by identifying the characteristic Cerenkov rings produced by identifying the characteristic Cerenkov rings produced by the electrons ...the electrons ...

Approximate # of Events after 1-2 YearsApproximate # of Events after 1-2 Years

MiniBooNE Sensitivity: 2 yr’s of MiniBooNE Sensitivity: 2 yr’s of

• The major backgroundsThe major backgrounds

– misid misid ’s from CC ’s from CC

– misid misid 00’s from NC ’s from NC

• Uncertainties in these Uncertainties in these rates to be rates to be < 5%< 5% in each in each case.case.

• ee‘s Intrinsic to the beam ‘s Intrinsic to the beam have a different energy have a different energy distribution than distribution than oscillation oscillation ee‘s‘s

– Event energy can be Event energy can be measured using measured using scintillation lightscintillation light

SummarySummary

• All civil construction projects for MiniBooNE are All civil construction projects for MiniBooNE are essentially complete.essentially complete.

• The detector instrumentation is complete and the oil The detector instrumentation is complete and the oil fill is well under way.fill is well under way.

• MiniBooNE is on schedule for taking first data later this MiniBooNE is on schedule for taking first data later this summer.summer.

• The biggest issue facing the experiment at this point The biggest issue facing the experiment at this point is the Booster’s ability to deliver the required number is the Booster’s ability to deliver the required number of protons.of protons.

– The limits will be due to radiation levels both in the The limits will be due to radiation levels both in the tunnel and above ground.tunnel and above ground.