Why accelerator-based oscillation physics may be the best place to find
The NextThe Next RealRealSurprise!Surprise!
Janet Conrad,Columbia University
Because...Neutrinos are a relatively unexplored frontierandAccelerators are developing so rapidly
There is a special opportunity hereto find something really unexpected
Recent technology revolutions for accelerator-based neutrinos:
Nearly MegaWatt beams (with the promise of Multi-MegaWatts soon:
SC RF Linacs, etc.) Improved secondary focusing Selectable energy ranges, narrow band beams GPS High statistics 2ndary production and xsec experiments
(e.g. HARP, BNL-E910, MIPP, FINeSSE...) Innovative ideas for even better accelerators:
FFAG, neutrino factory, beta beams
Opening Up OpportunitiesUsing Accelerator-basedOscillations Searches....
Soon: MiniBooNENear Term: Minos, Opera, T2K, Nova
Long Term: Neutrino Factory, Beta Beam
The opportunity for surpriseextends beyond oscillation searches too...
See talk by Mike Shaevitz
It would be a big surprise if ....
LSNDwas
RIGHTI'll eat my hat
Nearly 49,000 Coulombs of protons on upstream target
Baseline 30 m
Neutrino Energy 20-55 MeV,
167 tons Liquid scintillator
1220 phototubes
combined analysis allowed region
The LSND Experiment at LANL(1993-1998)
:87.9 ± 22.4 ± 6.0 (4.σ)
νe events observed in aνµ beam ???
P(νµ νe)= sin22θ sin2(1.27∆m2L/Ε)
∆m122
∆m232
ν1
ν2
ν3
Problem:
∆m132 = ∆m12
2 +∆m23
2
It must be new physics. It could be new muon-decay physics (TWIST) It could be new oscillation physics (MiniBooNE)
If LSND is not due to a fluctuation or an unknown systematic
(or one of the other results must change due to systematics or new physics)
MiniBooNE:
Booster K+
target and horn detectordirt (~450 m)decay region absorber
primary beam tertiary beamsecondary beam(protons) (mesons) (neutrinos)
Keep L/E same while changing systematics
P(νµ νe)= sin22θ sin2(1.27∆m2L/Ε)
E~1GeV
The MiniBooNE Beam:
µ → e νµ νe
K→ π e νe
Produced via 8 GeV protons on tgt
Secondary production measuredat the HARP experiment:
Focusing via a horn
50 m decay path for secondaries
in-situ kaon decay monitor
The MiniBooNE Detector
• 12 meter diameter sphere
• Filled with 950,000 liters of undoped mineral oil
(events produce both Cerenkov and Scintillation γ's)• Light tight inner tank with 1280 photomultiplier tubes• Outer veto region with 240 PMTs. •We measure charge and time for each tube
Many in situ monitoring systems...
resonant:
coherent:
Preliminary
+0
Coming soon...Resonant π+
production studies
Crucial if we plan to do precision ocillation physics!
Right now: Calibration & Cross Section Studies:
Updated Appearance Sensitivity
● νe signal events
● NC π0 misIDs
● Beam νe events
● νe signal and background breakdown
● Reasonable signal separation with 1021 POT
Monte Carlo
Monte Carlo
There aresterile
neutrinosNot a chance!
It would be a big surprise if ....
Z decay indicates 3 active neutrinos!
Another neutrino with m<45 GeVwill have to be sterile
νeνµ
ντ
νs
Ue1 Ue2 Ue3 Ue4 Uµ1 Uµ2 Uµ3 Uµ4
Uτ1 Uτ2 Uτ3 Uτ4Us1 Us2 Us3 Us4
ν1ν2
ν3
ν4
=
But it could mix with the others...
...thus be observed via oscillations
We know...
Why search?
Interesting from a theoretical point of view:The simplest extension to a model with neutrino massSterile neutrinos ''fall out'' of GUTS and Extra Dimensions Theories
Why should the sterile neutrino be light? maybe a new symmetry Why not massless? maybe Planck scale corrections
They can improve models for the R-process in supernovae (which requires oscillations)
Ye
Ye = 1/(1+(n/p)(Ye small has neutron excess)
present theoriesFrom Strumia, Neutrino '04:
Luckily, Experiments are more restrictive/suggestive!
Treat LSND as a positive signal
CDHS sees an effect in LSND mass range (near detecto2σ)
(Sorel, Conrad , Shaevitz., hep-ph/0305255)
Limits ~90% CL from atmospheric < 30%solar < 10%
Short baseline experiments:
This pulls the fit at about 20 eV2
Compatibility Level = 4%3+1 Models do not show high compatibility...
3+2 Models do showcompatibility....
NSBL LSND
90% CL
95% CL
99% CL
Best Fit: ∆m412=0.92 eV2 , Ue4=0.121 , Uµ4=0.204 , ∆m51
2=22 eV2 , Ue5=0.036 , Uµ4=0.224
Compatibility Level = 30%Allowed region for 3+2 "joint analysis"@90% CL
Comparing''Null Short Baseline''to LSND
1σ, 2σ
What does this mean for cosmology?
Hannestad astro-ph/0303076
Need to vary Ho in global fitsas you vary the mass,,,,
K. Abazajian hep-ph/0307266 J. Beacom, astro-ph/0404585 R. Mohapatra, hep-ph/047194
The latest from BBN fits:Cyburt, Fields, Olive, Skillman, astro-ph/0408033
at 68% CL (1σ) 2.67<Nν<3.85
...It would mean we'd have a lotof surprised cosmologists!
Including CMB/LSS too:
There are mechanisms whichsubstantially reduce cosmic ν's
NeutrinosDecay
That can'tbe true!
It would be a big surprise if ....
ν2 →ν3 + J Implies a non-zero mass difference between 2 neutrino states:
Which means mixing is possible as well:
So the most general formula for survival probability would be:
Where the lifetime appears as:
hep-ph/9810121hep-ph/9907421
And is assumed to be a function of the 2 neutrino masses
Isn't neutrino decay already ruled out by Super K?
Best fit oscillation: Neutrino Decay:
Errors are statistical
only
Errors are statistical
only
χ2/dof=37.9/40 (Prob=56%)
Fit, including systematic errors...
χ2/dof=49.1/40(Prob=15%)
hep-ph/0404034
There is 3σ betweenχ2 min...but...
Long Base Line experiments: An idea pioneered by K2K... who showed a 3.9σ osc. signal at Nu'04!
Expected: 150 ± 11.6
The ideal place to look:
But not enough statistics todifferentiate decay from oscillations...
8m octagonal steel & scintillator tracking calorimeter
Magnetized Iron (B~1.5T)
484 planes of scintillator
Beam begins Jan '05
running with cosmic ν's now....
The Next to Turn On: NuMI/Minos
Near DetectorDet. 2
Det. 1
Far Detector:segmented Iron
calorimeter detector
upward goingneutrino ratescompared to Bartol'96 flux
Neutrino decay in NuMI/Minos
Solid histogram: Flux at Soudan with no osc or other new physics,Dashed: Flux with oscillations (SK best fit)Points: Flux for neutrino decay
There is a big differencebetween the models atlow energy!
θ23
is exactly
45o
No Way!
It would be a big surprise if ....
None of the ''well−measured'' anglesin the quark sector or the neutrino sector,
are ''maximal''
solar only
solar+KamLAND...Except, for, possibly,the atmospheric oscillation
WHY MAXIMAL MIXING?see Grimus, hep-ph/0405261
A new symmetry group, eg: Z2, D4 models
max
max
Expected Minos capability:solid = 90% CL
d(sin2 2θ23)~5% with 25E20 protons on target (~6 years)
Is it maximal mixing?
SK: 90% CL and best fit (✭)
OPERA data can be combined also νµ → ντ appearance
NuMI runningwill be 4E20 p.o.t/year
Begins in 2006
And T2K can improve on this further!
Approved Dec, 2003Expected to run: 2009
Plan is to use a 2.5o off-axis beam& the existing Super K detector
Soudan
Macro
SK
CP violation is HUGE
in the lepton sectorYou're
kiddingme!
It would be a big surprise if ....
From Atmosphericand Long Baseline
DisappearanceMeasurements From Reactor
DisappearanceMeasurements
From Solar NeutrinoMeasurements
From Long BaselineAppearance
Measurements
The Mixing Matrix:The CP Violation Parameter
s13
has to be large (>1%)to have a chance at all!
CP violation
Posc(να→ νβ) ≠ Posc(να→ νβ)
∆m2<0∆m2>0
Posc(να→ νβ)
P osc
( να→
νβ)
CP
CP + matter,∆m2 <0
CP + matter, ∆m2 >0
δCP parameter
To untangle,you need different baselines!e.g.
T2K and Nova(Proposed off-axis FNAL-Minn.)
0
π
Can we tell at 3σ that δ ≠ 0 or π???
largemedium& small reactor expt.sensitivity
With a Multi-MegaWProton Driver
Nature'sreal value
For nature'sreal values of δ and sin2 2θ13,the experimentcan see that P
ν ≠ P⎯ ν at 3σ
2450km baseline
1MW source
½MT detector
5×107sec exposure
If the CP Violation signal is not 90 or 270 degrees,How can we see it?
VLBνO
We sawsomething
evenstranger!
Try to bepractical!
It would be a big surprise if ....
To go furtherwe will need
The Next Generationof accelerators....
A Neutrino Factory ..... or ..... A Beta Beam Facility
High Intensity Well defined flavor content Well defined energy distribution
Not in mylifetime!
You're kidding
me! No Way!
Not a chance!
Gimme a break!
I'll eat my hat
.
.
MiniBooNE
Minos
CNGS
T2K
Nova
VLBνO
Beyond!
LSN
D
ster
iles
deca
y
max
. mix
CPV
Bey
ond!
Accelerator-based oscillation studies may be the best,most versatile way to search for the next BIG surprise!
Backup Slides
Theoretical Justification for 3+2 .... examples from the last 6 months
THE STERILE NEUTRINO: FIRST HINT OF 4TH GENERATION FERMIONS?By Stephen Godfrey, Shouhua Zhu. May 2004. 4pp. ** Temporary entry ** e-Print Archive: hep-ph/0405006
LARGE MIXING FROM SMALL: PSEUDODIRAC NEUTRINOS AND THE SINGULAR SEESAW.By G.J. Stephenson,Jr. (New Mexico U.), T. Goldman (Los Alamos), B.H.J. McKellar, M. Garbutt (Melbourne U.),. LA-UR-04-1736, Apr 2004. 26pp. Extension of hep-ph 0307245. e-Print Archive: hep-ph/0404015
TWO LIGHT STERILE NEUTRINOS THAT MIX MAXIMALLY WITH EACH OTHER AND MODERATELY WITH THREE ACTIVE NEUTRINOS.By Wojciech Krolikowski (Warsaw U.),. IFT-04-7, Feb 2004. 12pp.Published in Acta Phys.Polon.B35:1675-1686,2004e-Print Archive: hep-ph/0402183
(3+2) NEUTRINO SCHEME FROM A SINGULAR DOUBLE SEESAW MECHANISM.By K.L. McDonald, B.H.J. McKellar, A. Mastrano (Melbourne U.),. Jan 2004. 5pp.e-Print Archive: hep-ph/0401241
SIMPLE MODEL FOR (3+2) NEUTRINO OSCILLATIONS.By K.S. Babu, Gerhart Seidl (Oklahoma State U.),. OSU-HEP-03-15, Dec 2003. 12pp.e-Print Archive: hep-ph/0312285
CPT Violation
Mass Spectrum Model:LSND
atmos, Kamland atmospheric
solar
Antiν: ν:
hep-ph/0210411 Barenboim, Lykken
Quantum Gravity Decoherence Model:
disfavored unless steriles are also invoked
Additional mixing induced by singular space-time configurations(wormholes, microscopic black holes, geons = ''space time foam'')
fit to data: χ2/DOF = 60.7/56 hep-ph/0404014, 0406035 Barenboim, Mavromatos
Lorentz Invariance Violation:Kostelecky and Mewes, hep-ph/0308300
Fits to neutrino data can, in principle, accommodate an LSND signal
hep-ph/0308299, Barger, Marfatia, Whisnant
TWIST:
& MiniBooNE antineutrino running:
Sorel and Whisnant, preliminary
Posc(να→ νβ) ≠ Posc(να→ νβ)
CP Violation in 3+2
How the Nova sensitivity was calculated:
Code: a package written by Mike Shaevitz for APS Nu Study.(includes osc. prob. code from S.Parke)
Purpose: Study relative contributions of Reactor, T2K, Novato atmospheric ∆m2 studies individually, in groups, as fn of time.
Agreement between Groups:A meeting between representatives of the SuperBeams and Reactor APS Study Groups (SW, JC, DM, BM/MD, GB, EB, MS, GF)led to agreement on this code, statistical methods & presentatation layout.
How the code works, in general:
1) Generate data (osc. probs) for a given point in δ and sin2θ13 space.2) Find the minimum χ2 demanding δ=0 but allowing θ13 and θ23 to vary3) The 2σ limit curve is where the χ2=4
The main focus of MiniBooNE right now:Precision modeling/understanding of beam and detector...
Optical Model:● Light Creation
– Cerenkov – Scintillation
● Light Propagation– Fluorescence
– Scattering– Absorption
Secondary Production Model:new data from BNL 910
Calibration:● Michel electrons● Tracker & Cube system