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50th Rencontres de Moriond, Cosmology Session21 March 2016
Interplay between cosmology andlaboratory experiments:
two examples from neutrino physics
Martina GerbinoOKC and Nordita, Stockholm University
M. Gerbino 50th Rencontres de Moriond, Cosmology 1/13
● Two examples of the interplay between cosmology andlaboratory searches
● The three active massive neutrinos: how we constraintheir mass
OscillationsCosmologyKinematic measurementsNeutrinoless double beta decay
● The additional (MeV) sterile neutrino: is it a viablesolution to the Lithium problem?
Overview
M. Gerbino 2/13
COSMOLOGY
OSCILLATIONS
DOUBLE BETA DECAY
BETA DECAY
The jigsaw pieces
50th Rencontres de Moriond, Cosmology
M. Gerbino 3/13
Lesgourgues and Pastor, 2006
Neutrino oscillations
Oscillations are only sensitiveto the squared mass difference
Open questions:● What is the hierarchy?● What is the absolute scale mass● What is the neutrino nature?
Degenerate
50th Rencontres de Moriond, Cosmology
M. Gerbino 4/13
Abazaijan et al, 2013
Cosmological probes
TT spectrum
Matter spectrum
BB spectrum Lensing potentialspectrum
50th Rencontres de Moriond, Cosmology
M. Gerbino 5/13
Tightest constraints from cosmologyBUT
model dependent
PL -> power law shape of the primordial PSPCHIP -> Polynomial interpolation, noassumption about primordial shape
Di Valentino, Gariazzo, MG, Giusarma, Mena, 2016
Limits from cosmology
50th Rencontres de Moriond, Cosmology
M. Gerbino 6/13
Kinematic measurements
50th Rencontres de Moriond, Cosmology
M. Gerbino 7/13
Neutrinoless double-beta decay
50th Rencontres de Moriond, Cosmology
M. Gerbino 8/13
Normal HierarchyInverted Hierarchy
PlanckTT,TE,EE+lowP+BAO+Oscillations (2014 global fit)
Currently and in thenear future, cosmology
is the most powerfulprobe for neutrino
masses
MG, Lattanzi, Melchiorri, 2016
Joint constraints from current data
50th Rencontres de Moriond, Cosmology
M. Gerbino 9/13
Currently and in the near future, cosmology isthe most powerful probe for neutrino massesNext Generation laboratory experiments areexpected to be as constraining as cosmology
Crucial role of NME uncertainties
MG, Lattanzi, Melchiorri, 2016
Normal Hierarchy Inverted Hierarchy
Current dataForthcomingNext Generation INext Generation II
Dashed -> FiducialNMESolid -> Marginalized
Joint constraints from current and future data
50th Rencontres de Moriond, Cosmology
M. Gerbino 10/13
MeV-sterile neutrino decay as a viable cosmological solution to the ''Lithium problem'' (Poulin and Serpico, 2015)
Photodisintegration of 7Beafter thermal BBNprevent 7Li production(non-thermal BBN)
Pagano, Salvati, Lattanzi, MG, Melchiorri, in prep.
MeV sterile neutrino decay and 7Li
50th Rencontres de Moriond, Cosmology
M. Gerbino 11/13
Mixing angles withactive neutrinos
Sterile neutrino mass
● Additional non-thermal relativistic degrees of freedomconstraints from CMB anisotropies
● Energy injection from electromagnetic decay channelsconstraints from CMB spectral distorsionsconstraints from baryon-to-photon ratio and baryon abundance from BBN andCMB anisotropies
● Constraints on the mixing angles from laboratory (distinguish between Dirac andMajorana)
● Constraints on element abundances (Li and D) from astrophysics measurements
Responsible for Bephotodisintegration
Decay channels and observable effects
50th Rencontres de Moriond, Cosmology
M. Gerbino 12/13
DIRAC
MAJORANA
Pagano, Salvati, Lattanzi, MG, Melchiorri, in prep.
Limits on the sterile-active mixing angles
50th Rencontres de Moriond, Cosmology
Preliminary
M. Gerbino 13/13
● Neutrino physics is a preferred scenario for the interplay betweencosmology and laboratory measurements
● Cosmological probes are currently the most powerful in constrainingneutrino masses
● The possibility to discard inverted hierarchy and to measure theneutrino mass from cosmology only seems around the corner
● Next generation laboratory avenues are expected to be as sensitive ascosmological probes
● Perfect agreement between cosmological and laboratory bounds onMeV-sterile neutrino as a solution to the Lithium problem
● Slight improvement of the constraints on the sterile-active mixingangles (though highly model dependent)
Conclusions
50th Rencontres de Moriond, Cosmology