Seesaw 25 Paris, 10-11/06/04 P. Binétruy, APC, Paris.

Seesaw 25

Paris, 10-11/06/04

P. Binétruy, APC, Paris

Thursday June 10th

Morning Session Chairman P. Frampton (Univ. of North Carolina)

09:30 Welcome P. Binétruy (LPT, Orsay & APC, Paris)09:40 Seesaw and the riddle of mass P. Ramond (Gainesville) 10:20 Leptogenesis T. Yanagida (Tokyo)

11:00 Coffee break

11:30 Various realizations of the seesaw mechanism R.N. Mohapatra (Maryland) 12:00 Seesaw mechanism and GUTs G. Senjanovic (Trieste)

Afternoon Session (1) Chairman S. Bilenky (SISSA, Trieste)

14:30 The experimental evidence for neutrino mass K. Heeger (Berkeley) 15:10 Textures and flavour models G.G. Ross (Oxford) 15:40 Seesaw mechanism and renormalization group effects M. Lindner (Munich)

16:10 Coffee break

Afternoon Session (2) Chairman E. Ma (Univ. of California, Riverside)

16:40 Seesaw mechanism and supersymmetry A. Masiero (Padua) 17:10 CP violation in the seesaw mechanism J. Hisano (Tokyo)

SEESAW 25 The programSEESAW 25 The program

Friday June 11th

Morning Session (1) Chairman R. Hahn (Brookhaven Nat. Lab.)

09:00 13 and CP violation in the lepton sector C. Hagner (Hamburg) 09:30 Seesaw mechanism and the baryon asymmetry M. Raidal (Tallinn) 10:00 Various realizations of leptogenesis and neutrino mass constraints Th. Hambye (Oxford)

10:30 Coffee break

Morning Session (2) Chairman G. Raffelt (MPI, Munich)

11:00 Seesaw mechanism and extra dimensions E. Dudas (Orsay)11:30 Neutrinos and astrophysics S. Hannestad (Odense) 12:00 Detectors for low-energy neutrinos and CDM S. Schoenert (Heidelberg)

Afternoon Session Chairman C. Albright (Fermilab)

14:00 Seesaw mechanism beyond neutrino physics T. Appelquist (Yale)14:30 Alternatives to the seesaw mechanism A. Yu. Smirnov (Trieste) 15:00 Searching for the absolute neutrino mass scale Ch. Weinheimer (Bonn) 15:30 Can one reconstruct the seesaw parameters? S. Davidson (Durham)

16:00 Coffee break

16:30 Round table Moderator J. Orloff (LPC, Clermont-Ferrand) « How to probe the origin of neutrino masses? » G. Gratta (Stanford) - B. Kayser (Fermilab) - S. Raby (Columbus) - J.W.F. Valle (Valencia) - Ch. Wetterich (Heidelberg)

The seesaw mechanism places the neutrino center stage :

M = mLT MR

-1 mL

Left-Rightsymmetry

GUT

Leptogenesis

Inflation

SUSY

LeptonFlavour

violations

Gravitinoproblem

Mohapatra

Senjanovic, Lindner

Hambye, Raidal, Lindner

Flavor symmetries

Ramond, Ross

Yanagida

MasieroExtradimensions

Dudas


M = mLT MR

-1 mL

Left-Rightsymmetry

GUT

Mohapatra

Senjanovic, LindnerFlavor

symmetries

Ramond,Ross

QuickTime™ et undécompresseur TIFF (LZW)

sont requis pour visionner cette image.

Mohapatra

seesawthors

Courtesy of Daniel Vignaud



Mohapatra

GUTS

LR



Importance of renormalization group effectsLindner

A new perspective for the seesaw mechanism :



Bla

Bla

Ross



Ramond

Need to identify the absolutemass scale !

THE ABSOLUTE VALUES OF NEUTRINO MASSESFROM COSMOLOGY

NEUTRINOS AFFECT STRUCTURE FORMATIONBECAUSE THEY ARE A SOURCE OF DARK MATTER

HOWEVER, eV NEUTRINOS ARE DIFFERENT FROM CDM BECAUSE THEY FREE STREAM

1eVFS Gpc 1~ −md

SCALES SMALLER THAN dFS DAMPED AWAY, LEADS TOSUPPRESSION OF POWER ON SMALL SCALES

NEUTRINOS AFFECT STRUCTURE FORMATIONBECAUSE THEY ARE A SOURCE OF DARK MATTER

S. Hannestad

m eV m eV

m eV m eVMa ’96

m eV

BEST FIT TO DATA IS NOT AT m = 0, EVEN IF NOINFORMATION ON BIAS IS USED

HOWEVER, m = 0 IS NOT EXCLUDED EVEN AT 2

THE PRESENT UPPER BOUND ON NEUTRINO MASS IS

C.L. 95% @eV 8.0≤m

Warning : THERE COULD BE MORE THAN ONE NON-STANDARD EFFECT, SEVERELY BIASING THE PARAMETER ESTIMATE

S. Hannestad



C. Weinheimer



from C. Weinheimer



Ramond



Ross :


M = mLT MR

-1 mL

Leptogenesis

Inflation

Gravitinoproblem

Hambye, Raidal, Lindner

Yanagida

SUSY



Yanagida



YanagidaMatter is created at the end of inflation

But gravitinos are produced by thermal scattering processes after inflation



TR < 104-5 GeV

for m3/2 ~ TeV

Yanagida favors light gravitino:

100 keV < m3/2 < 10 GeV


M = mLT MR

-1 mL

SUSY

LeptonFlavour

violations

MasieroExtradimensions

Dudas



BLABLA

Masiero



Masiero

Typology of seesaw or Seesaw or not seesaw?



Hambye

Type I

Type II or induced triplet?

Magg, Wetterich ‘80

Can one test the seesaw idea? NO !

• One cannot test a mechanism.

• One can only test a theory, i.e. the realization of this mechanism in an explicit theory

A Yu Smirnov

light sterile neutrinos are found (LSND/MiniBOONE)

neutrino mass spectrum turns out to be quasi-degenerate

Again, both these features can be accommodated in seesaw:

Seesaw + additional symmetry -> three active + 1 sterile neutrino

- Seesaw I + symmetry (e.g., SO(3))- seesaw II + symmetry - ``cascade seesaw’’:

R.Mohapatra

S.Petcov, A.S.E.MaJ. Valle

0 mD 0 m = mD 0 MD 0 MD M

If MD = A mD,and M = M0I If MD = A mD,and M = M0I

m ~ M0 /A2 I m ~ M0 /A2 I

A Yu Smirnov

Discovery of the neutrinoless double beta decayDiscovery of the neutrinoless double beta decay

LeptogenesisLeptogenesis Difficult to test also

In SUSY context: lepton violating decays, EDM, ...

In SUSY context: lepton violating decays, EDM, ...

Indirect, assumptions...

Easy to disprove seesaw as the dominant mechanism of neutrino mass generation

Will not prove that seesaw is the main mechamism

Roundtable : C. Wetterich

Induced triplet (type II seesaw) mechanism dominates if :

• maximal - mixing from generation symmetry (1 - sin2 < 0.01)

• degenerate neutrino masses

Heated debate around these statements….

25 years later, the seesaw mechanism is alive and well

Thanks to the local organizing committee, in particular S. Lavignac, J. Dumarchez and I. Cossin

Seesaw 25 Paris, 10-11/06/04 P. Binétruy, APC, Paris.

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Transcript of Seesaw 25 Paris, 10-11/06/04 P. Binétruy, APC, Paris.