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

CvB standard features Number density today Energy density today Neutrinos decoupled at T~MeV, keeping a “thermal” spectrum Number density today Energy density today massless massive G. Mangano NO-VE 2008 G. Mangano NO-VE 2008

CvB details At T~me, e+e- pairs annihilate heating photons … and neutrinos. Non thermal features in v distribution (small effect). Oscillations slightly modify the result f=fFD(p,T)[1+δf(p)] G. Mangano NO-VE 2008 G. Mangano NO-VE 2008

e , δf x10 10-2 effect G. Mangano NO-VE 2008

CvB details More radiation Fermi-Dirac spectrum with temperature T and chemical potential =vTv Raffelt More radiation G. Mangano NO-VE 2008

PLANCK /Tv very small (bad for detection!) BBN, CMB (LSS) + oscillations Cuoco et al 04 PLANCK /Tv /Tv Hamann, Lesgourgues and GM et al 08 G. Mangano NO-VE 2008

CvB for optimists V produced by decays at some cosmological epoch Early on: (TBBN> T>TCMB) Thermal FD spectrum Distortion from Φ decay Cuoco et al ‘05 Late (T<< TCMB): Unstable DM (e.g. Majoron) Lattanzi and Valle ’07 Lattanzi et al (in progress) G. Mangano NO-VE 2008

Cosmic Microwave Background Formation of Large Scale Structures CvB indirect evidences Primordial Nucleosynthesis BBN Cosmic Microwave Background CMB Formation of Large Scale Structures LSS T ~ MeV T < eV flavor dependent Flavor blind G. Mangano NO-VE 2008

Effect of neutrinos on BBN 1. Neff fixes the expansion rate during BBN D 3He 7Li 4He 2. Direct effect of electron neutrinos and antineutrinos on the n-p reactions G. Mangano NO-VE 2008 G. Mangano NO-VE 2008

Effect of CvB on CMB and LSS Mean effect (Sachs-Wolfe, M-R equality)+ perturbations Melchiorri and Trotta ‘04 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 How to deal with: Boltzmann eq. + Poisson Sing and Ma ’02 Ringwald and Wong ‘04 G. Mangano NO-VE 2008

. Milky Way (1012 MO) . @ Earth Ringwald and Wong ‘04 G. Mangano NO-VE 2008

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 G. Mangano NO-VE 2008

Presently Cavendish torsion balances Torque on frozen magnetized macroscopic piece of material of dimension R Presently Cavendish torsion balances The only well established linear effect in GF Coherent interaction of large De Broglie wavelength Energy transfer at order GF2 Cabibbo and Maiani ’82 Langacker et al ‘83 G. Mangano NO-VE 2008

Detection II: GF2 V-Nucleus collision: net momentum transfer due to Earth peculiar motion Coherence enhances Zeldovich and Khlopov ’81 Smith and Lewin ‘83 Backgrounds: solar v + WIMPS G. Mangano NO-VE 2008

Detection III Accelerator: vN scattering hopeless v capture (see later) LHC Cosmic Rays (indirect): resonant v annihilation at mZ Absorption dip (sensitive to high z) Emission: Z burst above GZK (sensitive to GZK volume, (50 Mpc)3) G. Mangano NO-VE 2008 Ringwald ‘05

A ’62 paper by S. Weinberg and v chemical potential G. Mangano NO-VE 2008

Massive neutrinos and neutrino capture on beta decaying nuclei () e (A, Z) (A, Z  1) Neutrino Capture on a Beta Decaying Nucleus e () e (A, Z) (A, Z  1) G. Mangano NO-VE 2008

v’s are NOT degenerate but are massive! Weinberg: if neutrinos are degenerate we could observe structures around the beta decaying nuclei endpoint Q v’s are NOT degenerate but are massive! 2 mv gap in electron spectrum around Q dn/dEe m= 0 m 0 Q Ee-me m Cocco et al ’07 see also Lazauskas et al ’07 Blennow ‘08 2m G. Mangano NO-VE 2008

Neutrino masses Terrestrial bounds Cosmology ve <2 eV (3H decay) Courtesy of A.Marrone Terrestrial bounds ve <2 eV (3H decay) v <0.19 MeV (pion decays) v <18.2 MeV ( decays) Cosmology Bounds on i mi G. Mangano NO-VE 2008 G. Fogli et al. 2007

Rates Slow (neutral) particle capture Nuclear form factors (shape factors) uncertainties: use beta observables G. Mangano NO-VE 2008

Background    signal/background >1 It works for <mv m Te dn/dTe Observing the last energy bins of width  m Te 2m signal/background >1 It works for <mv G. Mangano NO-VE 2008

3H Beta decaying nuclei having BR() > 5  selected from 14543 decays listed in the ENSDF database G. Mangano NO-VE 2008

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 G. Mangano NO-VE 2008

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 G. Mangano NO-VE 2008

vAP Collaboration CvB map 20?? Conclusions vAP Collaboration CvB map 20?? G. Mangano NO-VE 2008