and

Neutrino Factory 2004, based onRob Fardon, A.E.N., Neal Weiner; astro-ph/0309800David B. Kaplan, A.E.N., Neal Weiner; hep-ph/0401099Kathryn Zurek, hep-ph/0405141Kiyoshi Shiraishi, unpublished

1998, First Convincing evidence for Physics Beyond the Standard Model from

SuperK, evidence for atmospheric neutrino oscillations

But, the“Breakthrough of the Year” is the supernovae evidence for the acceleration of the universe

Einstein was wrong about having blundered? (Cosmological Constant?)

“Why Now” and finetuning are evidence for the Anthropic Principle?

Strong Evidence for two kinds:

1. 23% Dark Matter -> some garden variety pressureless clumpy fluid

2. 73% “Dark Energy” -> exotic negative pressure smoothsubstance

usually attributed to the energy of the vacuum⎯energy density which does not dilute with expansion and is therefore equivalent to Einstein’s cosmological constant. I will assume this is zero.

sometimes assumed to be some weird dynamical “quintessence” substance with equation of state parameter w near -1 which nevertheless does not clump (not your typical nonrelativistic stuff)

“Smooth, Dark, Tension” Sean Carroll

• Negative Pressure=Tension• Smooth Tension= Oxymoron? • “Normal” Stuff under tension prefers to Clump• Weird particle physics counterexamples: vacuum energy a slowly rolling scalar field (m~H-1~ 10-33eV) frustrated network of strings/domain walls relativistic, freely streaming particles

After Six Years of Surprises, Do we Almost Completely Understand

Neutrinos Now?

FlavorCompositionof MassEigenstates

Absolute mass scale? CP? Majorana or Dirac? LSND outlier?

Why recent Concordance in the Why recent Concordance in the neutrino oscillation Industry?neutrino oscillation Industry?

Why recent Concordance in the Why recent Concordance in the neutrino oscillation Industry?neutrino oscillation Industry?

Neutrinos are Special! Expect exotic physics to be discovered there! WindowWindow on the Dark Sector!

Can mix with ‘dark’ fermions (aka sterile neutrinos)

Can thus experience ‘dark forces’ much more strongly than other particles

Oscillations are sensitive to tiny GUT suppressed operators (standard seesaw)

Environment dependence of oscillations is sensitive to new millimeter range forces which are subgravitational strength for other particles

Beyond the Standard Model

Subject still in experimental youthNeutrino oscillations offer incredible sensitivity to new forces, high scales, ultraweak interactions, new statesConventional Wisdom about neutrinos, neutrino expts. has always been wrong!

Coincidences?

Density of “Dark Energy” ~ (2 10-3 )4 eV 4

Solar Neutrino Mass2 splitting ~ (4 10-3 )2eV 2

Atmospheric Neutrino Mass2 splitting ~ (3 10-2 ) 2eV 2

Convincing evidence for Dark Energy found in 1998 Convincing evidence for Neutrino Oscillations found in

1998 Low Scale SUSY gravitino mass ~ 10-3 eV

More Coincidences-Why so complicated?

Can dark energy be related to something we know?

Dark Matter? We know scaling behavior of dark matter from large scale structure. Dark energy currently scales very differently. Scaling behavior of dark energy must have recently changed (Why Now?)Neutrinos? Could neutrino energy density scale like dark energy?Requires neutrino ‘mass’ to increase with scale factor

Isn’t varying neutrino mass crazy?

No !

Varying ‘Mass’ is Everywhere!

Index of refractionKS regeneration

Quasi particles in condensed matterMSW effectAll Standard Model fermion mass terms depend

on value of Higgs scalar which can vary (slightly)All known masses depend on environmentThe issue is not ‘whether’, but ‘how much’ neutrino mass should vary !

A simple MassVaryingNeutrino Model

.

Assume “Dark Sector” (= unknown particles with no standard Model charges) contains A scalar field A A fermion field n A Yukawa coupling A n n A scalar potential V ( A )

Assume “Our sector” contains Active Neutrinos Higgs Field HAllow tiny (y =O (10-12) ) coupling y H n

Neutrino mass matrix ( )0 y H

y H A

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

Neutrino Masses vary as A-1

Neutrino mass matrix ( )0 y H

y H A

For large <A> light neutrino mass is ( y H) 2/ A

n

n

Assume V ( A ) slowly increasing function of A.

V is then slowly decreasing function of the light neutrino mass

V(A (m) ) ~ mww

Neutrino mass increases adiabatically as neutrino density dilutes Combined neutrino + scalar potential energy decreases slowly

What is the Scale?

We have 2 pieces of evidence suggesting a milli-eV scale for new physics.This is also the inverse cosmic neutrino spacing.A milli-eV scale for the A potential (and mass) leads to Dark EnergyContrast with ‘cosmon’ type quintessence model, which requires a mass scale of 10-33 eV.

Smoothness of MaVaN Dark Energy

• When ’s go nonrelativistic, they gravitationally clump at large scales

• MaVaN’s go nonrelativistic very late (z= a few)• MaVaN’s get lighter and more relativistic inside clumps =>

‘anti-clumping mechanism’• Dark energy much smoother than neutrinos V (n) (1+w)

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

Sterile Neutrinos?

Sterile neutrino mass increasing function of neutrino density Mixing with sterile neutrino decreasing

function of neutrino density Simple to reconcile sterile neutrino with

BBN mass always much heavier than temperature

May similarly evade Supernovae bounds

Can we test MaVaN Dark Energy? Cosmological tests of neutrino mass from large scale

structure: MaVaN mass was much lighter at high redshift.

Model independent relation: m= (1+w) V/n (V= dark energy density) No terrestrial sources of high scalar neutrino density

(neutrino density weighted by (m/E)), relative to cosmological, other than nuclear fireball.

Main interesting astrophysical source of high scalar neutrino density is supernova.

Generic tests difficult, not impossible.

A A should have coupling to mattershould have coupling to matter

Loop suppressed and/orLoop suppressed and/or

Planck/String scale suppressedPlanck/String scale suppressed

Possible very interesting terms:Possible very interesting terms:

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• Recent unofficial, preliminary analysis of SuperK atmospheric neutrinos by Kiyoshi Shiraishi assuming no oscillations in air fits all data well

• Very weak (consistent with LSND?) upper bound on mass squared difference in rock from contained, partially contained events, K2K

• reanalysis of upward through going and upward stopping muons underway, probably yields best upper bound on m2 in rock

Constraints on StandardNeutrinos

Constraints from oscillations in HighDensity Material only

Conventional Wisdom: need > 3 neutrinos to get 3 independent masses squared, and oscillations involving extra dark states constrained by Bugey, CDHS, Cosmology, and Supernova, so LSND must be wrong

To Do: Theorists

Model building exploration MaVaN consequences for Supernova How much room for non standard environment dependence

in Solar/atmospheric/terrestial neutrino oscillations? Consequences for flavor dependence/energy spectrum of

astrophysical neutrino sources Early Universe cosmology of acceleron More general constraints on sterile neutrinos from

supernovae, cosmology

To Do: Experimentalists Document and consider environment of neutrino path in neutrino

oscillation experiments Consider 13 measurements in reactor experiments with pathlength

in air and in rock Consider environment of neutrinos in direct mass search and

measurements Short baseline experiments to search for heavier sterile neutrinos

with small mixing angles; consider varying density of material in neutrino path

Effects of environment in neutrino oscillations?

decay depends on density of source?

Tritium endpoint searches for absolute mass depends on density of source?

Cosmologically “impossible” sterile neutrinos?

Cosmologically “inconsistent” neutrino masses?

A MiniBooNE signal for disappearanceor e

appearance