NEUTRINO COSMOLOGY

STEEN HANNESTAD UNIVERSITY OF AARHUS

COPENHAGEN, 17 DECEMBER 2005

e

NEUTRINOS, THE MICROWAVE BACKGROUND,AND LARGE SCALE STRUCTURE

WMAP 1-YEAR DATA

BOOMERANG 2003 FLIGHT – PUBLISHED DATA IN JULY 2005

ASTRO-PH/0507494

SDSS SURVEY

SDSS POWER SPECTRUM

DATA FROM THE LYMAN-ALPHA FOREST PROVIDES AN INDEPENDENT MEASUREMENT OF POWER ON SMALL SCALES, BUT IN THE SEMI-LINEAR REGIME (CROFT ET AL. 2002, MCDONALD ET AL. 2003). THE RELIABILITY OF THE INFERRED MATTER SPECTRUM IS CONTROVERSIAL!

CROFT ET AL. DATA

SDSS

EISENSTEIN ET AL. 2005 (SDSS)

THE SDSS MEASUREMENT OF BARYON OSCILLATIONS IN THEPOWER SPECTRUM PROVIDE A FANTASTICALLY PRECISEMEASURE OF THE ANGULAR DISTANCE SCALE AND SETSCOMPLEMENTARY LIMITS ON AND w

SO, WHAT ABOUT NEUTRINO PHYSICS?

NEUTRINO MASS HIERARCHY AND MIXING MATRIX

ABSOLUTE NEUTRINO MASSES

STERILE NEUTRINOS (LEPTOGENESIS)

NUMBER OF RELIC NEUTRINOS / RELATIVISTIC ENERGY

3

2

1

132313231223121323122312

132313231223121323122312

1313121312

ccscsscsccss

cssssccssccs

scscce

3 x 3 UNITARY MATRIX

)cos( 1212 c

)sin( 1313 sETC

FLAVOUR (INTERACTION)STATES

MASS(PROPAGATION)STATES

THE NEUTRINO MASS MATRIX(WITH ONLY ACTIVE SPECIES)

Araki et al. hep-ex/0406035

STATUS OF 1-2 MIXING (SOLAR + KAMLAND)

STATUS OF 2-3 MIXING (ATMOSPHERIC + K2K)

Maltoni et al. hep-ph/0405172

Normal hierarchy Inverted hierarchy

If neutrino masses are hierarchical then oscillation experimentsdo not give information on the absolute value of neutrino masses

However, if neutrino masses are degenerate

no information can be gained from such experiments.

Experiments which rely on the kinematics of neutrino massare the most efficient for measuring m0 (or 0 decays)

catmospherimm 0

SOLAR KAMLAND

ATMO. K2K

FROM LESGOURGUES & PASTOR

”DEGENERATENEUTRINO MASSES”

Tritium decay endpoint measurements have reached limitson the electron neutrino mass

This translates into a limit on the sum of the three mass eigenstates

(95%) eV 3.22/1

22 iei mUm

e

eV 7im

Mainz experiment, final analysis (Kraus et al.)

MEASUREMENT OF THE NEUTRINO MASS FROM TRITIUM DECAY

FROM G. DREXLIN

Only possible if neutrinos are massive Majorana particles

Neutrinoless double beta decay

(T1/ 2) 1 G0 (E,Z) MGT0

gV2

gA2 MF

02m

2

me20:

 

Q-value (keV)

Isotope Nat. abund. (%)

(PS 0v)–1 (yrs x eV2)

(PS 2v) –1 (yrs)

Ca 48 4271 0.187 4.10E24 2.52E16Ge 76 2039 7.8 4.09E25 7.66E18Se 82 2995 9.2 9.27E24 2.30E17Zr 96 3350 2.8 4.46E24 5.19E16Mo 100 3034 9.6 5.70E24 1.06E17Pd 110 2013 11.8 1.86E25 2.51E18Cd 116 2802 7.5 5.28E24 1.25E17Sn 124 2288 5.64 9.48E24 5.93E17Te 130 2529 34.5 5.89E24 2.08E17Xe 136 2479 8.9 5.52E24 2.07E17Nd 150 3367 5.6 1.25E24 8.41E15

Heidelberg -Moscow• Five Ge diodes (overall mass 10.9 kg) Five Ge diodes (overall mass 10.9 kg) isotopically enriched ( 86%) in isotopically enriched ( 86%) in 7676GeGe • Lead box and nitrogen flushing ofLead box and nitrogen flushing of the detectors the detectors • Digital Pulse ShapeDigital Pulse Shape Analysis (factor 5 reductionAnalysis (factor 5 reduction)) Peak at 2039 keVPeak at 2039 keV

THE HEIDELBERG – MOSCOW EXPERIMENT

0

peak r

eg

ion

Spectrum

Latest HD-Moscow results

Statistical significance: 54.98 kg x yr

Including pulse shape analysis: 35.5 kg x yr

T1/2 > 1.9 x 1025 yr (90% CL)

(installed Nov. 95, only 4 detectors)

m < 0.35 eV

Heidelberg –Moscow evidence???

Evidence ?

H.V. Klapdor-Kleingrothaus et al, Phys. Lett. B 586, 198 (2004)

T1/2 = 0.6 - 8.4 x 1025 yr m = 0.17 - 0.63 eVSubgroup of collaboration

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

eV 932

mh

mP

P

8

BY MEASURING THEMATTER POWER SPECTRUM

)()()( 0 kTkPkP

T(k) = Transfer functionIT IS POSSIBLE TO OBTAINCONSTRAINTS ON m

ROUGHLY ONE FINDS THAT

EISENSTEIN, HU & TEGMARK ’99

0.3 eV

1 eV

0 eV

m eV m eV

m eV m eVMa ’96

WHILE NEUTRINO MASSES HAVE A PRONOUNCED INFLUENCE ONTHE MATTER POWER SPECTRUM ON SCALES SMALLER THAN THEFREE-STREAMING SCALE THERE IS ONLY A VERY LIMITED EFFECTON THE CMB

COMBINED ANALYSIS OF CMB, 2dF AND LY-ALPHA DATA BY THEWMAP TEAM (Spergel et al. 2003)

BOUND FROM SDSS + WMAP + BIAS + SDSS LYMAN ALPHA(SELJAK ET AL. ASTRO-PH/0407372)

C.L. 95% @ eV 42.0 m

FOGLI ET AL. HEP-PH/0408045 FIND ~ 0.5 eV IN A SIMILAR STUDY

BOTH RESULTS RELY ON THE ABILITY TO MEASURE THEEXACT MATTER FLUCTUATION AMPLITUDE ON SMALLSCALES

THIS LOOKS VERY IMPRESSIVE, BUT IT NEEDS A REALITY CHECK!

A SELECTION OF RECENT RESULTS ON m

WMAP ONLY 13 eV @ 95% WMAP

SPERGEL ET AL. (WMAP) 2003

0.69 eV @ 95% WMAP, CMB, 2dF, H0

STH 2003 1.01 eV @ 95% WMAP, CMB, 2dF, H0

ALLEN, SMITH, BRIDLE 2003

eV @ 68% WMAP, CMB, 2dF, H0

TEGMARK ET AL 2003

1.8 eV @ 95% WMAP, SDSS

BARGER ET AL 2003

0.65 eV @ 95% WMAP, CMB, 2dF, SDSS H0

CROTTY ET AL. 2004

1.0 eV @ 95% WMAP, CMB, 2dF, SDSS H0

STH 2005 1.5 eV @ 95% WMAP, SDSS,

SNI-A, H0

3.026.056.0

FROM LESGOURGUES & PASTOR

HEIDELBERG –MOSCOW

GENERAL HEALTH WARNING

A GENERIC PROBLEM WITH USING COSMOLOGICAL OBSERVATIONSTO PROBE PARTICLE PHYSICS:

IN GENERAL, LIKELIHOOD ANALYSES ARE CARRIED OUT ON TOPOF THE MINIMAL COSMOLOGICAL STANDARD MODEL

HOWEVER, THERE COULD BE MORE THAN ONE NON-STANDARDEFFECT, SEVERELY BIASING THE PARAMETER ESTIMATE

ANY DERIVED LIMIT SHOULD BE TREATED WITH SOME CARE!

HOW CAN THE BOUND BE AVOIDED?

CHANGE THE PRIMORDIAL SPECTRUMYES, BUT LEADS TO OTHER PROBLEMS

TOPOLOGICAL DEFECTS?NO

MAKE THE NEUTRINOS STRONGLY INTERACTINGNO

CHANGE THE DARK ENERGY EQUATION OF STATEYES (BUT NO)

……

STH, ASTRO-PH/0505551 (PRL)

EXAMPLE:

THERE IS A VERY STRONG DEGENERACY BETWEEN NEUTRINOMASS AND THE DARK ENERGY EQUATION OF STATE

BREAKING THE m - w DEGENERACY WITHOUT USING THE LY-FOREST DATA:

1) USE WEAK LENSING (TALK BY HUITZU TU)

2) USE ANOTHER MEASURE OF THE ANGULAR SCALE (BARYON ACOUSTIC OSCILLATION PEAK)

USING THE PRESENT SDSS DATA + CMB (WMAP, BOOMERANG)+ SNI-A (SNLS) DATA IT IS POSSIBLE TO DERIVE AN EXTREMELYSTRONG BOUND ON THE NEUTRINO MASS BECAUSE AND w ARE ESSENTIALLY FIXED

GOOBAR, HANNESTAD, MÖRTSELL, TU (IN PREPARATION)

NmbAnHwBM ,,,,,,,,, 010 FREE PARAMETERS

WMAP, BOOMERANG, CBISDSS, 2dFSNLS SNI-A

NmbAnHwBM ,,,,,,,,, 010 FREE PARAMETERS

WMAP, BOOMERANG, CBISDSS, 2dFSNLS SNI-A, SDSS BARYONS

mbAnHBM ,,,,,,, 08 FREE PARAMETERS

WMAP, BOOMERANG, CBISDSS, 2dFSNLS SNI-A, SDSS BARYONS

95% @ eV 3.2 m 95% @ eV 48.0 m 95% @ eV 44.0 m

NO KNOWLEDGE OF THE BIAS OR LYMAN-ALPHA IS NEEDED FOR THISBOUND!

FROM LESGOURGUES & PASTOR

NEW BOUND

NEUTRINO MASS HIERARCHY AND MIXING MATRIX

ABSOLUTE NEUTRINO MASSES

STERILE NEUTRINOS

NUMBER OF RELIC NEUTRINOS / RELATIVISTIC ENERGY

ANALYSIS OF ALL THE PRESENTDATA, INCLUDING BOOMERANG-03GIVES A PRESENT LIMIT OF

C.L.) (95% 2.54.2 N

THIS IS ENTIRELY COMPATIBLEWITH THE MOST RECENT 4-HEDETERMINATION

0092.02495.0 YCyburt et al. 2004 (astro-ph/0408033)

AT PRESENT THERE IS NO SIGNIFICANT BOUND ON EXTRA THERMAL RELICS, EITHER AT BBN OR AT RECOMBINATION!

STH 2005, JCAP 2006

See also: Crotty, Lesgourgues & Pastor ’03STH ’03, Pierpaoli ’03, Barger et al. ’03

WHAT ABOUT OTHER LIGHT, THERMALLYPRODUCED PARTICLES?

NEUTRINOS

AXIONS

GRAVITONS

MAJORONS

AXINOS

RADIONS

...........

FOR ANY THERMALLY PRODUCED PARTICLE IT ISSTRAIGHTFORWARD TO CALCULATE THE DECOUPLINGEPOCH ETC.THE ONLY IMPORTANT PARAMETERS ARE

Xm

WHERE g* IS THE EFECTIVE NUMBER OF DEGREES OFFREEDOM WHEN X DECOUPLES.

*,XgAND

bosonsfor 3/4

fermionsfor 175.10

eV 183 *

2

X

XXX g

gmh

2

24

2X

FS 9.3log1Mpc 20

~Xm

XX

T

T

T

T

h

CONTRIBUTION TO DENSITY

FREE-STREAMING LENGTH

EW transition (~ 100 GeV)g* = 106.75

Density bound for a Majorana fermion

STH, hep-ph/0409108 (See also STH & G Raffelt, JCAP 0404, 008)Similar bound can be obtained for pseudoscalars (such a axions) – STH, Mirizzi & Raffelt 2005

Based on WMAP, SDSS, SNI-a and Lyman- data, No assumptions about bias!

MASS BOUND FOR SPECIES DECOUPLINGAROUND EW TRANSITION

eV 5m

DECOUPLING AFTERQCD PHASE TRANSITIONLEADS TO

eV 1m

Below QCD transition (~ 100 MeV) g* < 20

NOTE THAT MASS BOUNDS CANNOT BE DIRECTLY EXTENDEDTO RELIC PARTICLES WHICH MAKE UP MORE THAN A SMALLFRACTION OF THE TOTAL DENSITY!!

LYMAN-ALPHA ANALYSIS IS BASED ON THE ASSUMPTION THATTHE POWER SPECTRUM IS CLOSE TO A POWER-LAW

IF THERE IS EXPONENTIAL DAMPING THEN THE ”RAW” LYMAN-ALPHA DATA SHOULD BE USED DIRECTLY AND COMPAREDWITH NUMERICAL SIMULATIONS

THIS HAS BEEN DONE BY VIEL ET AL. astro-ph/0501562

VIEL ET AL. astro-ph/0501562

THE 2LOWER BOUND ON THE MASS OF THE WDM PARTICLE IS ~ 500 eV

THE BEST FIT IS NOT ATINFINITE MASS ALTHOUGHTHE EFFECT IS NOT STATISTICALLY SIGNIFICANT

WHAT IS IN STORE FOR THE FUTURE?

LARGE SCALE STRUCTURE SURVEYS2dF (completed) 250.000 galaxies SDSS (ongoing) 1.000.000 galaxies

COSMOLOGICAL SUPERNOVA SURVEYSSNLS, DARK ENERGY CAMERA, SNAP

WEAK LENSING SURVEYS (Pan-STARRS 2006, LSST 2012, …..)

BETTER CMB TEMPERATURE MEASUREMENTS

Satellites Balloons InterferometersWMAP (ongoing) Boomerang CBIPlanck (2007) Maxima, Archaeops DASI

CMB POLARIZATION MEASUREMENTS

Satellites Balloons GroundWMAP (ongoing) Boomerang PolatronPlanck (2007) DASI

FROM LESGOURGUES & PASTOR

PROJECTED SENSITIVITIES FROM FUTURE EXPERIMENTS

THE KATRIN EXPERIMENT IN KARLSRUHE WILL MEASURE THE EFFECTIVE ELECTRON NEUTRINO MASS TO 0.2 eV (90%) BY USING TRITIUM DECAYS, STARTING IN 2008

CONCLUSIONS

NEUTRINO PHYSICS IS THE PRIME EXAMPLE OF HOW TO USECOSMOLOGY TO DO PARTICLE PHYSICS

THE BOUND ON NEUTRINO MASSES IS ALREADY AN ORDER OF MAGNITUDE STRONGER THAN THAT FROM DIRECT EXPERIMENTS, ALBEIT MORE MODEL DEPENDENT

WITHIN THE NEXT 5-10 YEARS THE MASS BOUND COULDREACH THE LEVEL NEEDED TO DETECT HIERARCHICALNEUTRINO MASSES

THE CLAIM FROM HEIDELBERG-MOSCOW WILL BE CHECKED