IFAE 06, Pavia, Aprile 2006 Sommario 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 m 2 -driven oscillations (about half-period seen in both cases)

+ m 2 m m 2 Abs.scale Normal hierarchy… OR… Inverted hierarchy mass 2 splittings Current interpretation of world data (-LSND) stable e around the following scenario (with flavors e ) :

A more quantitative summary of world neutrino oscillation data as of 2005 (with 2 errors) 2006, after MINOS (prelim.) Good news for CNGS-OPERA, since tau event rate ~( m 2 ) 2 : (2.6/2.4) 2 =1.17

Max Sioli ( Oscillazioni di neutrini con sorgenti artificiali ): MINOS 2006OPERA ~ (After MINOS: 12.8 x 1.17 = 15.0)

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

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

Solar matter effects (MSW) with standard size (V = 2 G F N e ) basically confirmed, but factor ~2 deviations still allowed (from V(x) a MSW V(x) with a MSW free)

Therefore, important to pursue spectroscopy in the poorly known low-energy solar range (Aldo Ianni, Oscillazioni di neutrini con sorgenti naturali ) LNGS mission: Measure Be flux

pep neutrinos with Borexino Basic idea : reduce 11 C cosmogenic background Method : tagging 11 C 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( m 2 ). In order to test the sign, we need interference of oscillation phase ( m 2 L/E) with another phase Q having known sign. Two options (barring exotics): + m 2 m m 2 Abs.scale Normal hierarchy… OR… Inverted hierarchy mass 2 splittings Q driven by matter effects (only in matter & for s 13 >0) Q driven by m 2 (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 in the next galactic supernova explosion (~3/century) (Alessandro Mirizzi, Fisica dei neutrini da Supernova ) E.g., observation of non-monotonic time spectra through inverse beta decay in water-Ch. detectors would: 1)Establish inverse hierarchy 2)Monitor the SN shock wave 3)Establish a lower bound on sin 2 13 (with sensitivity down to )

13 fundamental to access also leptonic CP violation (which vanishes when 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 at a 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: m 2 i 0 can affect spectrum endpoint. Sensitive to the effective electron neutrino mass (Flavio Gatti): 2) 0 2 decay: Can occur if m 2 i 0 and =. Sensitive to the effective Majorana mass and phases (Maura Pavan): 3) Cosmology: m 2 i 0 can affect large scale structures in (standard) cosmology constrained by CMB+other data (Marco Cirelli). Probes:

Spettrometri Calorimetri Sandro Vitale Re 20 eV2 eV0.2 eV 20 eV 2 eV 0.2 eV MAINZ TROITZK spettrometri elettrostatici KATRIN 2.2 eV spettrometri magnetici eV MANU MIBETA 26 eV 95%CL 15 eV 90%CL MARE Italian contribution to calorimetric spectroscopy and m limits, in perspective (Flavio Gatti)

1/2 > y at 90% C.L. 1/2 > y at 90% C.L. m < eV m < eV started in April 2003 long interruption for maintenance 2530 keV m < eV m < eV Cuoricino within 3 years 130 Te: Cuoricino NOW 130 Te: 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 induce positive correlations between any pair of the three observables (m, m, ), e.g.: m oscill. allowed 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)0 2 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?)

0 2 claim rejected: cosmological bound dominates [Green dotted line: a more aggressive <0.3 eV bound]

0 2 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 and their couplings, and we all hope to open this window with the LHC!

Check overall consistency … Identify the hierarchy … Probe the Majorana phases … (and the CP phase too…) Dreaming about future, precise nonoscillation + oscillation data …

Cosmic Rays -> Laura Patrizii