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NEUTRINO MASS FROM LARGE SCALE STRUCTURE
STEEN HANNESTAD CERN, 8 December 2008
e
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 either the kinematics of neutrino massor the spin-flip in neutrinoless double beta decay are the most efficient for measuring m0
catmospherimm 0
SOLAR KAMLAND
ATMO. K2KMINOS
LIGHTEST
INVERTED
NORMAL
HIERARCHICAL DEGENERATE
Lesgourgues and Pastor 2006
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 FROM K2
11
43/1
TT
AVAILABLE COSMOLOGICAL DATA
WMAP-5 TEMPERATURE POWER SPECTRUM
M NOLTA ET AL., arXiv:0803.0593
LARGE SCALE STRUCTURE SURVEYS - 2dF AND SDSS
SDSS SPECTRUMTEGMARK ET AL. 2006
astro-ph/0608632
m = 0.3 eV
FINITE NEUTRINO MASSES SUPPRESS THE MATTER POWERSPECTRUM ON SCALES SMALLER THAN THE FREE-STREAMINGLENGTH
m = 1 eV
m = 0 eV
P(k
)/P
(k,m
EISENSTEIN ET AL. 2005 (SDSS)
THE SDSS MEASUREMENT OF BARYON OSCILLATIONS IN THEPOWER SPECTRUM PROVIDES PRECISE MEASURE OF THE ANGULAR DISTANCE SCALE AND TURNS OUT TO BE EXTREMELY USEFUL FOR PROBING NEUTRINO PHYSICS
NEUTRINO MASSES ISA POTENTIALLY IMPOR-TANT SYSTEMATIC ERROR NOT ACCOUNTEDFOR IN THE ANALYSIS
GOOBAR, HANNESTAD, MÖRTSELL, TU 2006
Astro-ph/0807.3551
FIRST MEASUREMENT OF THERADIAL BARYON ACOUSTICFEATURE
PROVIDES VERY PRECISE MEASUREMENT OF H(z)
NOW, WHAT ABOUT NEUTRINOPHYSICS?
WMAP-5 ONLY ~ 1.3 eVWMAP + OTHER 0.67 eV
Komatsu et al., arXiv:0803.0547
WHAT IS THE PRESENT BOUND ON THE NEUTRINO MASS?
GOOBAR, HANNESTAD, MÖRTSELL, TU (JCAP 2006)
NmbAnHwBM ,,,,,,,,, 010 FREE PARAMETERS
WMAP, BOOMERANG, CBISDSS, 2dFSNLS SNI-A
NmbAnHwBM ,,,,,,,,, 010 FREE PARAMETERS
WMAP, BOOMERANG, CBISDSS, 2dFSNLS SNI-A, SDSS BARYONS
sBM QNmbAnH ,,,,,,,,,, 012 FREE PARAMETERS
WMAP-3, BOOMERANG, CBISDSS, 2dF, HSTSNLS SNI-A, SDSS BARYONS
95% @ eV 62.0 m
No BAO
BAO
LY-BAO+LY-
USING THE BAO DATA THE BOUNDIS STRENGTHENED, EVEN FORVERY GENERAL MODELS
IN MORE RESTRICTED MODELS THE BOUND IS STRONGER(BUT BEWARE OF THE PARAMETER DEGENERACIES)
PRELIMINARY RESULT:
WITH WMAP-5 AND RADIAL BAO ALONE ONE FINDS AN UPPER BOUND OF ~ 0.4 – 0.5 eV FOR THE SUM OF NEUTRINO MASSES(STH & HAUGBØLLE, ARXIV:0812.????)
THIS IS A VERY ROBUST RESULT AND VERY INSENSITIVETO MODEL SPACE SELECTION!
ADDITIONAL RELATIVISTIC ENERGY DENSITY
COMPARISON WITHSH & RAFFELT ’04
,0
extraSM,eff
NN
COULD BY CAUSED BY A NUMBER OF DIFFERENT EFFECTS
ADDITIONAL PARTICLE SPECIES
DECAY OF HEAVY SPECIES
NEUTRINO CHEMICAL POTENTIAL
…..
USING WMAP3+SDSS-LRG+SNI-A
C.L.) (95% 9.3 0.26.1
N
HAMANN, STH, RAFFELT, WONG arXiv:0705.0979 (JCAP)
IS EXCLUDED AT ABOUT 5 SIGMA!0N
THIS RESULT IS CONSISTENT WITH WMAP-5
C.L.) (68% 4.4 4.14.1
N (WMAP-5 ONLY)
ALSO DE BERNARDIS ET AL 2008, HAMANN, LESGOURGUES & MANGANO 2008SELJAK, SLOSAR & MCDONALD 2007
WHAT IS IN STORE FOR THE FUTURE?
BETTER CMB TEMPERATURE AND POLARIZATIONMEASUREMENTS (PLANCK)
LARGE SCALE STRUCTURE SURVEYS AT HIGH REDSHIFT
MEASUREMENTS OF WEAK GRAVITATIONAL LENSINGON LARGE SCALES
Distortion of background images by foreground matter
Unlensed Lensed
WEAK LENSING – A POWERFUL PROBE FOR THE FUTURE
H
drPa
gHC m
0
2
240 ),/(
)(
16
9
H
dng
0
''
)'()'(2)(
FROM A WEAK LENSING SURVEY THE ANGULAR POWER SPECTRUMCAN BE CONSTRUCTED, JUST LIKE IN THE CASE OF CMB
),/( rP MATTER POWER SPECTRUM (NON-LINEAR)
WEIGHT FUNCTION DESCRIBING LENSINGPROBABILITY
(SEE FOR INSTANCE JAIN & SELJAK ’96, ABAZAJIAN & DODELSON ’03,SIMPSON & BRIDLE ’04)
STH, TU, WONG 2006
STH, TU & WONG 2006 (ASTRO-PH/0603019, JCAP)
THE SENSITIVITY TO NEUTRINO MASS WILL IMPROVE TO < 0.1 eVAT 95% C.L. USING WEAK LENSINGCOULD POSSIBLY BE IMPROVED EVEN FURTHER USING FUTURELARGE SCALE STRUCTURE SURVEYS
FUTURE SURVEYS LIKE LSST WILL PROBE THE POWER SPECTRUM TO ~ 1-2 PERCENT PRECISION
WE SHOULD BE ABLE TO CALCULATE THE POWER SPECTRUM TO AT LEAST THE SAME PRECISION!
”LSST” ERROR BARS
-1
512 h-1 Mpc
z = 0
z = 4
EVOLUTION OF NEUTRINO DENSITY FIELD
mP
P
6.9~
FULL NON-LINEAR
mP
P
8~
LINEAR THEORY
Brandbyge, STH, Haugbølle, Thomsen, arXiv:0802.3700 (ApJ)
NON-LINEAR EVOLUTION PROVIDES AN ADDITIONAL AND VERY CHARACTERISTIC SUPPRESSION OF FLUCTUATION POWER DUE TO NEUTRINOS (COULD BE USED AS A SMOKING GUN SIGNATURE)
LIGHT NEUTRINOS ARE ALMOST IMPOSSIBLE TO FOLLOW AT HIGH ZBECAUSE OF THERMAL NOISE
SOLUTION: FOLLOW NEUTRINOS USING LINEAR THEORY WITH A GRID-BASED METHOD, SIMULTANEOUSLY WITH THE CDM / BARYONN-BODY SOLVER
BRANDBYGE & STH 2008 (IN PREPARATION)
eV 6.0m
DIFFERENCE BETWEEN GRID AND PARTICLE METHOD
eV 2.1m eV 3.0m
THIS METHOD WORKS FOR REALISTIC NEUTRINO MASSES (BELOW0.5-0.6 eV) AT BETTER THAN 0.5% PRECISION
THE COMPUTATIONAL SPEED IS ESSENTIALLY THE SAME AS FOR A PURE CDM SIMULATION (FACTOR ~ 10 OR MORE FASTER THAN WITHNEUTRINOS AS PARTICLES)
THE GRID METHOD IS NOT USEFUL FOR CALCULATING THE LOCALRELIC NEUTRINO DENSITYFOR THIS THE 1-PARTICLE BOLTZMANN EQUATION SHOULD BE USED(RINGWALD & WONG 2004, STH, RINGWALD, TU & WONG 2005)
CDM -PARTICLE -GRID
z = 49
z = 4
z = 0
z = 49
z = 4
z = 0
WONG 2008
FOR RELATIVELY SMALL NEUTRINO MASSES THE RESULTS CAN BE REPRODUCED USING HIGHER ORDER PERTURBATION THEORYFOR SCALES UP TO k ~ 0.1 h / Mpc (SAITO ET AL. 2008, WONG 2008)THESE CALCULATIONS ALSO ASSUME THAT NEUTRINO STRUCTURESARE LINEAR
CONCLUSIONS
NEUTRINO PHYSICS IS PERHAPS THE PRIME EXAMPLE OF HOW TO USE COSMOLOGY TO DO (ORDINARY) PARTICLE PHYSICS
THE BOUND ON NEUTRINO MASSES IS SIGNIFICANTLYSTRONGER THAN WHAT CAN BE OBTAINED FROM DIRECT EXPERIMENTS, ALBEIT MUCH MORE MODEL DEPENDENT
FUTURE OBSERVATIONS WILL CONTINUE TO IMPROVE THESENSITIVITY TO NEUTRINO PROPERTIES