Hunting for Cosmological Neutrino Background (CvB)

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Hunting for Cosmological Neutrino Background (CvB) Gianpiero Gianpiero Mangano Mangano INFN, Sezione di INFN, Sezione di Napoli, Italy Napoli, Italy NO-VE 2008

description

NO-VE 2008. Hunting for Cosmological Neutrino Background (CvB). Gianpiero Mangano INFN, Sezione di Napoli, Italy. CvB standard features. Neutrinos decoupled at T~MeV, keeping a “thermal” spectrum. Number density today. Energy density today. massless. massive. CvB details. - PowerPoint PPT Presentation

Transcript of Hunting for Cosmological Neutrino Background (CvB)

Page 1: Hunting for Cosmological Neutrino Background (CvB)

Hunting for Cosmological Neutrino Background

(CvB)Gianpiero Gianpiero Mangano Mangano

INFN, Sezione INFN, Sezione di Napoli, Italydi Napoli, Italy

NO-VE 2008

Page 2: Hunting for Cosmological Neutrino Background (CvB)

G. Mangano NO-VE 2008

CvB standard features

Neutrinos decoupled at T~MeV, keeping a “thermal” spectrum

Number density today

eV 94.1

mh Ω i

i2

ν

52 101.7h Ω ν

Energy density today

Tπ11

)3(ζ6n

113

)(p,Tfπ)2(pd

n 3CMB2γνν3

3

ν

massless

massive

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G. Mangano NO-VE 2008

At T~me, e+e- pairs annihilate heating photons

γγ -ee

f=fFD(p,T)[1+δf(p)]

CvB details

… and neutrinos. Non thermal features in v distribution (small effect). Oscillations slightly modify the result

)(C,Em

G28

pM

Hpi 2W

F2

pt

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G. Mangano NO-VE 2008

e

,

δf x10

1e

pp/T

2

10-2 effect

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nn

32

3

TT

)3(121

nnn

L

42

2715

Raffelt

Fermi-Dirac spectrum with temperature T and chemical potential =vTv

More radiation

CvB details

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G. Mangano NO-VE 2008

/Tv very small (bad for detection!)

BBN, CMB (LSS) + oscillations

/Tv Hamann,

Lesgourgues and GM et al 08

/Tv

Cuoco et al 04

PLANCK

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CvB for optimists V produced by decays at some cosmological epoch

Early on: (TBBN> T>TCMB)

Late (T<< TCMB):

Unstable DM (e.g. Majoron) dm0

v H

1.0H0

Lattanzi and Valle ’07

Lattanzi et al (in progress)

Cuoco et al ‘05

Thermal FD spectrum

Distortion from Φ decay

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G. Mangano NO-VE 2008

CvB indirect evidences

T < eVT ~ MeV

Formation of Large Scale Structures

LSS

Cosmic Microwave Background

CMB

PrimordialNucleosynthesis

BBN

Flavor blind flavor dependent

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Effect of neutrinos on BBN 1. Neff fixes the expansion rate during BBN

38ππ

H

2. Direct effect of electron neutrinos and antineutrinos on the n-p reactions

v

eff3/4

xvR N114

87

17Li

3He

D

4He

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G. Mangano NO-VE 2008

Effect of CvB on CMB and LSSMean effect (Sachs-Wolfe, M-R equality)+ perturbations

Melchiorri and Trotta ‘04

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G. Mangano NO-VE 2008

CvB locally: a closer look

Neutrinos cluster if massive (eV) on large cluster scale

Escape velocity: Milky Way 600 Km/s

clusters 103 Km/s

)eV/m(s/Km106m/Tcv v3

vvv

How to deal with: Boltzmann eq. + Poisson

2

vvxv

Ga4

0amf xf

Sing and Ma ’02

Ringwald and Wong ‘04

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Milky Way (1012 MO)

.

@ Earth

Ringwald and Wong ‘04

.

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Detection I: Stodolsky effect

Energy split of electron spin states in the v background

requires v chemical potential (Dirac) or net helicity (Majorana)

Requires breaking of isotropy (Earth velocity)

Results depend on D or M, relativistic/non relativistic, clustered/unclustered

Duda et al ‘01

)nn(sgGE vvAF

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The only well established linear effect in GFCoherent interaction of large De Broglie wavelength

Energy transfer at order GF2

)x(n(x) xdGF v3

F Cabibbo and Maiani ’82

Langacker et al ‘83

Torque on frozen magnetized macroscopic piece of material of dimension R

23

vv3

27 s cmcm 100nn

10Rcm

A100

10a

Presently Cavendish torsion balances

212 s cm10a

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Detection II: GF2

V-Nucleus collision: net momentum transfer due to Earth peculiar motion

2v

2FvN EG

v

vNA

vv

Ep

pAN

vna

v

v

Tp

mp

25446 s cm100A

)1010(a

Zeldovich and Khlopov ’81

Smith and Lewin ‘83

Coherence enhancesmm1/m - T/1 vvv

3v

Ac A

NN

Backgrounds: solar v + WIMPS

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Detection IIIAccelerator: vN scattering hopeless

Cosmic Rays (indirect): resonant v annihilation at mZ eV

meV

10 4m2

mE

v

21

v

2Z

Absorption dip (sensitive to high z)

Emission: Z burst above GZK (sensitive to GZK volume, (50 Mpc)3)

Ringwald ‘05

v capture (see later)

18 yr10R

LHC

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A ’62 paper by S. Weinberg and v chemical potential

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Massive neutrinos and neutrino capture on beta decaying nuclei

e 'NN v

v e 'NN

)1Z,A()Z,A(e

e)1Z,A()Z,A(

e

e

()

(A, Z) (A, Z 1)

Beta decay

e

e

()Neutrino Capture on aBeta Decaying Nucleus

(A, Z) (A, Z 1)

)(

)(

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dn/dEe

Qm

Ee-me

m 0

m= 0

2m

2 mv gap in electron spectrum around Q

Weinberg: if neutrinos are degenerate we could observe structures around the beta decaying nuclei endpoint Q

v’s are NOT degenerate but are massive!

Cocco et al ’07

see also Lazauskas et al ’07

Blennow ‘08

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Neutrino masses

Terrestrial bounds

ve <2 eV (3H decay)

v <0.19 MeV (pion decays)

v <18.2 MeV ( decays)

Cosmology Bounds on i mi

Courtesy of A.Marrone

G. Fogli et al. 2007

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Rates

Nuclear form factors (shape factors) uncertainties: use beta observables

Slow (neutral) particle capture

ee2

v

EpGR

v/R

vvvv Rnnv

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Background

Observing the last energy bins of width

signal/background >1

It works for <mv

dn/dTe

m Te

2m

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3H

1272 nuclei

799 nuclei

Beta decaying nuclei having BR() > 5 selected from 14543 decays listed in the ENSDF database

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The 3H example

8 events yr-1 per 100g of 3H (no clustering)

up to 102 events yr-1 per 100 g of 3H due to clustering effect

signal/background = 3 for =0.2 eV if mv=0.7 eV

=0.1 eV if mv=0.3 eV

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Variation on the theme:

Beta-beams

Electron-capture nuclei (fighting with energy threshold!)

Best nucleus candidate?

Already there ? (Troisk anomaly) Unlikely large flux!!

Waiting for Katrin

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Conclusions

vAP Collaboration CvB map

20??