IFAE’06, Pavia, 19-21 Aprile 2006Sommario della Sessione:

Neutrini e Raggi Cosmici

Conveners:Laura Patrizii (INFN, Bologna)Eligio Lisi (INFN, Bari)

Speakers:Maximiliano Sioli (U. di Bologna)Aldo Ianni (INFN, LNGS)Marco Cirelli (Yale Univ.)Flavio Gatti (INFN, Genova)Maura Pavan (U. di Milano Bicocca)Michele Frigerio (CEA/Saclay)Alessandro Mirizzi (Univ. di Bari)Davide Meloni (INFN, Roma I)Michele Maltoni (ICTP, Trieste)Giorgio Riccobene (INFN, LNS)Daniel De Marco (U. of Delaware)Andrea Chiavassa (Univ. di Torino)Vincenzo Vitale (Univ. di Udine)Paola Salvini (INFN, Pavia)

Frequencies and amplitudes can be embedded in a 3 framework

Neutrino masses, mixing and oscillations are established facts

Super-K KamLAND

m2-driven oscillations m2-driven oscillations

(about half-period seen in both cases)

+m2

m2m2

21

3

3

-m2

Abs.scale Normal hierarchy… OR… Inverted hierarchy mass2

splittings

Current interpretation of world data (-LSND) stablearound the following scenario (with flavors ee ):

A more quantitative summaryof world neutrino oscillation data

as of 2005 (with 2 errors)

2006, after MINOS (prelim.)

Good news for CNGS-OPERA,since tau event rate ~(m2)2:

(2.6/2.4)2=1.17

Max Sioli (“Oscillazioni di neutrini con sorgenti artificiali”):

MINOS 2006 OPERA ~2006+5

(After MINOS: 12.8 x 1.17 = 15.0)

(2 , 3) oscillation parameters:Significantly higher accuracy in next-generationlong-baseline experiments T2K, NOvA (Max Sioli)

(1 , 2) oscillation parameters:Currently dominated by SNO (mixing) and by KamLAND (mass2 difference). Some improvements expected in both expt.

Solar matter effects (MSW) with standard size (V = 2 GF Ne ) basically confirmed, but factor ~2 deviations still allowed

(from V(x) aMSW V(x) with aMSW free)

Therefore, important to pursue spectroscopyin the poorly known low-energy solar range(Aldo Ianni, “Oscillazioni di neutrini con sorgenti naturali”)

BOREXINO @ LNGS mission: Measure Be flux

pep neutrinos with Borexino

• Basic idea : reduce 11C cosmogenic background

• Method : tagging 11C by tackling the produced (95%) neutrons in spallation interactions

…and maybe also (A. Ianni):

Strong competitors: KamLAND (Be, pep)SNO+ (pep)

Important to start the experiment as soon as possible …

The elusive mixing angle 13: current status

(Consistency of all data for small 13 is nontrivial)

The elusive mixing angle 13: future prospects(Max Sioli)

13 fundamental to access mass hierarchy and leptonic CP violation

Hierarchy = sign(m2). In order to test the sign, we needinterference of oscillation phase (m2 L/E) with another“phase” Q having known sign. Two options (barring exotics):

+m2

m2m2

21

3

3

-m2

Abs.scale Normal hierarchy… OR… Inverted hierarchy mass2

splittings

Q driven by matter effects (only in matter & for s13>0)Q driven by m2 (in any case, but very hard!)

Basically all current projects focus on the first option

If nature is kind enough, this option might be exploited inthe next galactic supernova explosion (~3/century)(Alessandro Mirizzi, “Fisica dei neutrini da Supernova”)

E.g., observation of non-monotonictime spectra through inverse beta decay in water-Ch. detectors would:

1) Establish inverse hierarchy2) Monitor the SN shock wave3) Establish a lower bound on sin213

(with sensitivity down to 10-4)

13 fundamental to access also leptonic CP violation (which vanisheswhen the full 3 parameter space is reduced to an effective 2 one).

If 13 nonzero, however, attempts to determine 13 and CP in future long-baseline experiments must face the occurrence of multiple solutions (“degeneracies” or “clones”), as discussed by Davide Meloni and Michele Maltoni

Several ways out have been explored through prospective simulations

E.g., by combining different appearance channels ata future neutrino factory:

2- golden+silver channels

solo golden

(Davide Meloni, “Violazione di CP nel settore leptonico”)

Or, by combining future long-baseline accelerator and atmospheric neutrino data:

(Michele Maltoni, “Sinergie fra neutrini da acceleratore e atmosferici”)

Absolute neutrino mass observables: (m, m, )

1) decay: m2i 0 can affect spectrum endpoint. Sensitive to

the “effective electron neutrino mass” (Flavio Gatti):

2) 02 decay: Can occur if m2i 0 and =. Sensitive to the

“effective Majorana mass” and phases (Maura Pavan):

3) Cosmology: m2i 0 can affect large scale structures in (standard)

cosmology constrained by CMB+other data (Marco Cirelli). Probes:

1990 1995 2000 2005 2010 2015

1990 1995 2000 2005 2010 2015

Spettrometri

Calorimetri

Sandro Vitale1985187Re

20 eV 2 eV 0.2 eV

20 eV

2 eV 0.2 eV

MAINZ

TROITZK

spettrometrielettrostatici

KATRIN

2.2 eV

2.2 eVspettrometrimagnetici

20-10 eV

MANU

MIBETA

26 eV95%CL

15 eV90%CL

MARE

Italian contribution to calorimetric spectroscopy and m limits, in perspective(Flavio Gatti)

1/21/2>> 2 10 2 10 2424 y at 90% C.L. y at 90% C.L.

mm << 0.3-0.7 eV 0.3-0.7 eV

started in April 2003

long interruption for maintenance

2530 keV

mm << 0.2-0.5 eV 0.2-0.5 eV

Cuoricino within 3 yearsCuoricino within 3 years

130 130 Te: Cuoricino NOWTe: Cuoricino NOW

Italian contributions to m searches: Pioneering +… Cuoricino, Cuore, Gerda …(Maura Pavan)

Constraints on from CMB + Large Scale Structure data (Marco Cirelli)

Oscillations fix the mass splittings and thus inducepositive correlations between any pair of the three observables (m, m, ), e.g.:

m

oscill.

allo

wed

i.e., if one observable increases, the other one (typically) also increases

Positive correlations

Partial overlap between NH and IH

Large (intrinsic) m spread due to unknown Majorana phases

Oscillation data only:

Current info from non-oscillation experiments:

1) decay: no signal so far. Mainz & Troitsk expts: m < O(eV)

2) 02 decay, no signal in all experiments, except in the most sensitive one to date (Heidelberg-Moscow). Rather debated claim.

Claim accepted: m in sub-eV range (with large uncertainties)

Claim rejected: m < O(eV).

3) Cosmology. Upper bounds: < eV/sub-eV range, depending on several inputs and priors. E.g., Lyman- data crucial to reach sub-eV bounds (but: systematics?)

02 claim rejected: cosmological bound dominates

[Green dotted line: a more aggressive <0.3 eV bound]

02 claim accepted: tension with cosmological bound(s)

No reasonable combination at face value, but: too early to draw definite conclusions

} expt+theo error

(Green dotted line:

<0.3 eV )

Absolute masses, hierarchy, CP violation, Majorana/Dirac nature, more accurate oscillation parameters also crucial to constrain model building (Michele Frigerio, “Modelli teorici per le masse dei neutrini”)

… together with the possible connections with other sectors of physics …

… including Higgs physics (Michele Frigerio)

… or cosmology, with radically new ideas (Marco Cirelli)

In both cases, we need to understand fundamental scalar fields andtheir couplings, and we all hope to open this window with the LHC!

Check overallconsistency …

Identify thehierarchy …

Probe theMajorana phases …

(and the CPphase too…)

Dreaming about future, precise nonoscillation + oscillation data …

Cosmic Rays -> Laura Patrizii