Results in Neutrino Physics Astrophysics Highlights Overview Highlights

Results in Neutrino Physics & Astrophysics : Highlights Ø Overview Ø Highlights in Neutrino Oscillation Results from Atmospheric, Solar, Accelerator and Reactor Neutrino Experiments Ø Future Directions & Projects Ø Outlook Henry T. Wong / 王子敬 @ Academia Sinica / 中央研究院

Neutrino Physics Road-Map Grand Unified Theories (GUT) Particle Physics L(n-mass) 0 mn’s; Uij’s 0 Structures & Compositions of Universe Øn-Oscil. Ømn’s Cosmology Øn-decays Ø 0 nbb Øb-spect. dist. Nuclear Physics Øanomal. int. Ø………. n’s as Probe Astrophysics

Neutrino Sources Observed window Ø n‘s everywhere: 300 per c. c. Ø from sun, supernovae, cosmic rays, reactors, accelerators, astrophysical sources, & relic Big Bang …

Cross Sections Strong Electro-magnetic Weak l(H 2 O) 250 light years ! Challenges of Neutrino Experiments : “How to Beat the Small Cross-Section? ” i. e. By building Massive Detectors while keeping cost/background Low !

at least as much neutrinos by mass as visible matter !

Solar Neutrinos

Super-Kamionkande ※ Water Cerenkov detector: 50 k tons, viewed by 11, 000+ =50 cm PMTs in 1000 m underground site in central Japan ※ Physics: solar n, atmospheric n , long baseline accelerator n, proton decays. . ※ Accidents (PMTs imploded) Nov 01, Ø 50% PMT data again end of 02 !! ØNo major deterioration in data quality

Measurement of Eccentricity of Earth’s Orbit !!! The Sun IS Burning !!

Sudbury Neutrino Observatory (SNO) ※ 1 kton Heavy Water Cerenkov detector: shielded by 7 k ton of water viewed by 9456 PMTs located 2000 m underground in Canada. ※ Physics: Solar n …

Standard Solar Model + Standard Particle Physics Model Solution of the “Solar Neutrino Problem”

Atmospheric Neutrinos Ønm disappearing, ne OK, ØStrong evidence : > 15 s Up-Down Asymmetry & Deficit ØBetter fits for nt appearing

KEK-Super. K (K 2 K) Accelerator n Flight path 250 km Deficit of nm at far detector spectral distortion

Kam. LAND Ø Long Baseline Reactor n (sensitive to 20% of world’s reactors !) Ø ave. flight path of 160 km Ø 1 kton liquid scintillator in old Kamiokande site Ø probe “LMA” for solar n Ø historical results only 5 years from approved !!!!

A “By-Product” : Earth’s Radiogenic Power : ØThermal measurements : 42 TW ØGeophysical Model : 16 TW ØKam. LAND measurement : < 60 TW

Neutrino Oscillations (in 2 -family language) Ø Neutrinos produced & detected as ne, nm , nt (“flavor eigenstates”) Ø Propagate as n 1 , n 2 (“mass eigenstates”) 3 families Ø Probability of producingνe & detecting as νe : Ø Matter Effect : Origin – ne+e (CC+NC) Vs nm +e(NC) at resonance

Dm 2 – : Summary PDG 2000: 2002 SK atm. n SNO solar n

2004 K 2 K : Consistent Checks to atm. n SK

+ observations of L/E oscillation signatures from SK atm-n & Kam. LAND (averaged)…. .

Three Families of Neutrino Mixing The Maki-Nakagawa-Sakata (MNS) matrix : Q 13 : crucial unknown towards CP-studies Possible CP Violation in n Sector:

Neutrino Mass Structures : ØNormal Vs Inverted Hierarchy ? ? ØQuasi-Degenerate Vs Hierarchical ? ? ØDirac Vs Majorana ? ? Dm 2 0= ? Dm 2 atm Dm 2 Normal Hierarchy: Dm 232>0 Inverted Hierarchy: Dm 232<0

Deeper Physical Questions ………. . In particular : ØIs 12+ Cabbibo = p/4 ? ØIs 23=p/4 ? ØIs 13 = 0 ? Ø……. . Mixing angles may reveal deeper/higher energy scale & symmetry principles

neutrino mass structures may reveal GUTs scale physics (e. g. See-Saw Mechanisms) :

Future Experimental Projects Ø Long baseline accelerator/reactor experiments (Nu. MI, CNGS, T 2 K, q 13 ……) ※Detailed studies of mixing matrices by oscillation studies Ø 0 nbb experiments ※ Distinguish mass hierarchy, fix absolute mass scales Ø Direct mass searches in b-decay ※ Probe degenerate mass structures Ø Neutrino properties (e. g. magnetic moments studies…) ※ How neutrino interacts/couples with outside world Ø Neutrino from sky and earth ※ do astronomy/earth science with neutrino sources, understand roles of neutrinos in astrophysics/geophysics

Long Baseline Accelerator Neutrino Projects : 730 km Nu. MI MINOS CNGS Icarus/OPERA

0 nbb Candidate Isotopes

Neutrino Mass Measurements cosmology & structure formation D. N. Spergel et al: Smn < 0. 69 e. V (95%CL) S. W. Allen et al: Smn = 0. 56 e. V (best fit) astrophysics: SN To. F measurements 0 nbb decay: 76 Ge 2 nbb |mee|=0. 44+0. 13 -0. 2 e. V b decay kinematics: microcalorimeters MAC-E spectrometers 187 Re 3 H Super. K, SNO, OMNIS + grav. waves: potential for ~1 e. V sensitivity? @ LNGS ´ 90 -´ 03 (71. 7 kg×y) NEMO 3

Ice. Cube High Energy Neutrino Telescope e. g. Volume ~km 3 !!

TEXONO Research Program in Taiwan KS NPS-II : 2 cores 2. 9 GW KS n Lab: 28 m from core#1

Reactor Neutrino Interaction Cross-Sections R&D : On-Going Data Taking: ØCoh. (n. N) ØSM s(ne) ØT < 1 ke. V Results & More Data: Ømn(ne) ØT ~ 1 -100 ke. V ØT > 2 Me. V

TEXONO KIMS @ Y 2 L Ø Install 5 g ULB-ULEGe at Y 2 L on January 2005 Ø Study background and feasibility for CDM searches Ø may evolve into a full-scale (1 kg) CDM experiment Yangyang (襄陽) Lab (Y 2 L) min. 700 m of rock overburden

Sensitivity Plot for CDM-WIMP search with 1 kg ULEGe at 100 e. V threshold ………

Summary & Outlook Ø Neutrinos are important but strange objects history of n physics full of surprises ! Ø Strong evidence. S of massive n’s & finite mixings Physics Beyond the Standard Model ! Ø More experiments & projects coming up EVEN MORE EXCITEMENT !