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Recent Results in Neutrino Physics & Astrophysics

Explore the recent results and significance of neutrino physics in solar, atmospheric, and reactor studies. Learn about the Texono research program in Taiwan and its contributions to understanding neutrino magnetic moments.

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Recent Results in Neutrino Physics & Astrophysics

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  1. Neutrino Physics: WHY & HOW Important recent results : solar + atm. + reactor n TEXONO research program in Taiwan  Kuo Sheng Reactor Lab  Results on Neutrino Magnetic Moment  R&D Program Recent Results in Neutrino Physics & Astrophysics Henry T. Wong / 王子敬 Academia Sinica / 中央研究院 @ IoP Colloquium Nov 2003

  2. Neutrino History • 1914: continuous b-spectra (Chadwick) • 1930: postulation of neutrinos (Pauli) • 1934: theory of b-decay (Fermi) calculation of s(np) (Bethe,Peierls) • 1956: observartion reactor ne(Reines,Cowan) • 1957: measurement of n helicity (Goldhaber) • 1962: discovery of accelerator nm(BNL) • 1968: observation of solar neutrinos (Davis) • 1974: discovery of weak neutral currents (CERN) 1980’s>>>>>>> False Alarm on Neutrino Mass Measurements <<<<<<<< • 1987: observation of supernova SN1987a n’s (IMB,Kamiokande) • 1989: three families of light neutrinos (CERN) • 1998: evidence of atmospheric neutrino oscillation (Super-Kam., …) • 2000: observation of nt(Fermilab) • 2001: evidence solar neutrino oscillation (SNO+SK+GALLEX ……) • 2002:evidence of accelerator (K2K) & reactor (KamLAND)n’s oscillation One of the most favorite subjects for Nobel Prizes ……

  3. Nobel Prize in Physics (2002)50% for n astrophys. : Ray. Davis Jr. (U. Penn) : “Classic” Chlorine Expt. Masatoshi Koshiba小柴昌俊(U. Tokyo) : Kamiokande & SuperK Citations leave room for future prizes on n physics !!! • 50% to Riccardo Giacconi, in X-Ray Astronomy

  4. Neutrino Physics Road-Map Grand Unified Theories (GUT) L(n-mass)0 Structures & Compositions of Universe mn’s;Uij’s 0 • n-Oscil. • mn’s • n-decays • 0nbb • b-spect.dist. • anomal. int. • ………. Particle Physics Cosmology Nuclear Physics Astrophysics n’s as Probe

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

  6. Challenges of Neutrino Experiments : “How to Beat the Small Cross-Section?” i.e.By building Massive Detectors  while keeping cost/background Low ! Cross Sections Strong Electro-magnetic Weak l(H2O)  250 light years !

  7. Super-Kamionkande ※ Water Cerenkov detector: 50k 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, 50% PMT data again end of 02 !!!

  8. Atmospheric Neutrinos • nm disappearing, ne OK, • Strong evidence : > 15s • Better fits for nt appearing e n n Atmospheric Neutrinos: Up-Down Asymmetry & Deficit

  9. Solar Neutrinos

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

  11. KEK-SuperK (K2K) Accelerator n Flight path 250 km Deficit of nm at far detector

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

  13. Pure D2O Phase Actual measurements : only detect e- (a burst of light) : deconvolute the channels

  14. (also Cl, Ga, diff. E) (also SK) Standard Solar Model + Standard Particle Physics Model ( 5s effect )

  15. Solar Neutrino Review :: Join forth-coming Seminar at ASIoP by Dr. Alan Poon (Lawrence Berkeley Laboratory) Dec 10, 2003. ***************************** “ One of the Great Achievement in Science in the Past 40 years ! “

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

  17. Detects deficit of reactor ne-bar ; agrees LMA of solar neutrinos

  18. Dm2 –  : Summary 2002 PDG 2000: SK atm. n SNO solar n

  19. KamLAND : picks LMA for solar n K2K : Consistent Checks to atm. n SK

  20. Solar LMA Solution (before Sept 03) + SNO Salt Results …..

  21. Three Families of Neutrino Mixing The Maki-Nakagawa-Sakata (MNS) matrix : Possible CP Violation in n Sector:

  22. Neutrino Mass Structures : • Normal Vs Inverted Hierachy ?? • Quasi-Degenerate Vs Hierarchical ?? Dm2 Atm. n Solar n ※absolute scale unknown

  23. Deeper Physical Questions ………..

  24. Matter & Energy Density Budget in the Universe (2003)

  25. CERN: CNGS to Gran Sasso (2006+) Fermilab: NuMI to MINOS (2004+) 730 km • Both with 730 km baseline accelerator n beams • Precision measurement of atm. n’s q23 • Explicit observation of nt + JHFSuperK (2007+)

  26. IceCube High Energy Neutrino Telescope Volume ~km3 !!

  27. TEXONO Overview Program: • Kuo-Sheng Reactor Neutrino Laboratory ※ reactor : high flux of low energy electron anti-neutrinos ※mn0  anomalous n properties & interactions • ※ n physics full of surprises , need intense n-source • study/constraint new regime wherever experimentally accessible • explore possible new detection channels • R&D Projects Poineering Efforts : “Zero-Background Experiment” ! • KS Expt:1st large-scale particle physics experiment in Taiwan • TEXONO Coll. : 1st big research Coll. % Taiwan & China [feature report in Science, Vol. 300, 1074 (2003) ]

  29. TEXONO* Collaboration W.C. Chang, K.C. Cheng, M.H. Chou, H.C. Hsu, C.H. Iong, G.C.Jon, F.S. Lee, S.C.Lee, H.B. Li, V. Singh, D.S. Su, P.K.Teng, H.T.K.Wong,  S.C. Wu Academia Sinica, Taipei, Taiwan W.P. Lai Chung Kuo Institute of Technology, Taipei, Taiwan C.H. Hu, W.S. Kuo, T.R. Yeh Institute of Nuclear Energy Research, Lungtan, Taiwan H.Y. Liao, S.T. Lin,M.Z. Wang National Taiwan University, Taipei, Taiwan F.K. Lin National Tsing Hua University, Hsinchu, Taiwan Z.M. Fang, R.F. Su Nuclear Power Station II, Kuosheng, Taiwan J. Bao, K.J. Dong, S. Jiang, L. Hou, Y.H. Liu, H.Q. Tang, B. Xin, Z.Y. Zhou Institute of Atomic Energy, Beijing, China J.Li, Y. Liu, J. Nie, Z.P.Mao, J.F.Qiu, H.Y.Sheng, P.L.Wang, X.W. Wang, D.X.Zhao, P.P.Zhao, B.A.Zhuang Institute of High Energy Physics, Beijing, China J.Q. Lu, T.Y. Chen Nanjing University, Nanjing, China Y. An, D.Z. Liu, Q. Yue, Y.F. Zhu Tsing Hua University, Beijing, China C.Y. Chang, G.C.C. Chang University of Maryland, Maryland, U.S.A. Co-Prinicipal Investigators Ph.D. Students • HISTORY • Initiate : Chang Chung-Yung 1996 • First Collab. Meeting/Official Start : October 1997 • First Paper : October 1998 • KS Reactor Experiment Installation : June 2000 • First Ph.D. : Liu Yan , July 2000 • First Physics Data Taking : June 2001. • First Physics Results: Dec 2002.

  30. Kuo-Sheng Nuclear Power Plant KS NPS-II : 2 cores  2.9 GW KS nLab: 28 m from core#1

  31. Kuo Sheng Reactor Neutrino Laboratory Front Gate Front View (cosmic vetos, shieldings, control room …..) Configuration: Modest yet Unique Flexible Design: Allows different detectors conf. for different physics Inner Target Volume

  32. KS Expt: Period I Detectors ULB-HPGe [1 kg] CsI(Tl) [46 kg] FADC Readout [16 ch., 20 MHz, 8 bit] Multi-Disks Array [600 Gb]

  33. mn with Reactor ne • mn  parametrize possible niLnjR + g vertices   both i = j “diagonal” & i  j “transition” moments • Experimental Probe:  Study ne + e- nX + e-  Focus on low recoil energy ※ sm  T–1 ※ decouples SM “background” [ ……… LE reactor f(ne) not accurately known]  Look for Excess in Reactor ON/OFF • Neutrino Radiative Decay (Gn):  sm & Gn related:  same vertices – real g for Gn Electron Recoil Spectra

  34. PDG Limit : 1.5 X 10-10mB (indirect seach from SK spectral shape) an allowed solution for the solar neutrino data (before KamLAND)

  35. KS/P1/Ge/mn : Results • Total 4712/1250 hours ON/OFF  No residual observed • Range of O(1 cpd) background c/f Dark Matter expt. • Fit OFF spectra to p5 Measure [fOFF;dfOFF ] (@c2/dof =80/96 ) • Fit ON spectra to • fOFF +fSM + k2fMM [10-10mB] • Fit Results (@c2/dof =48/49 ): k2= -0.4  1.3 (stat.)  0.4 (sys.) Limits derived : mn < 1.3 (1.0)  10-10mB @90(68)% C.L. H.B. Li et al., TEXONO Coll., Phys. Rev. Lett. 90, 131802 (2003)

  36. Reactor mn(ne) Sensitivities Gn Sensitivities

  37. Kuo Sheng Reactor Neutrino Laboratory : First Results

  38. Citation in AIP’s Physics News Update : 2003 2nd Entry for “Taiwan” / 1st Entry for “Academia Sinica” since 1991

  39. Doppel-Null Neutrino bleibt unmagnetisch Auch Nicht-Ergebnisse liefern Physikern Einsichten – zum Beispiel der Versuch, an Neutrinos ein magnetisches Moment zu messen. Ein solches Moment kann theoretisch auch bei neutralen Teilchen wie Neutrinos entstehen, wenn eine Eigendrehung die negativen und positiven Ladungsanteile herumwirbelt. Deshalb suchten die Forscher nach subtilen Abweichungen von der – ohnehin extrem schwachen – Wechselwirkung von Neutrinos aus einem Kernreaktor mit Elektronen. Ihr Resultat: Null, wie bei früheren Experimenten. Allerdings haben sie die Null genauer vermessen; die Fehlergrenze liegt etwa beim zehnmilliardsten Teil des magnetischen Moments des Elektrons ( Physical Review Letters, Bd.90, Nr.131802, 2003). Somit hält sich das Neutrino an die etablierte Theorie: Die elektromagnetische Wechselwirkung lässt es völlig kalt. Wärmer wurde hingegen das Verhältnis der beteiligten Forscher. Sie stammten aus der Volksrepublik China und aus Taiwan.

  40. 科學人雜誌 (Scientic American/Chinese) 2003年5月號

  41. Status & Plans HPGe [1 kg] : • mn + Gn : x2 more data improved background & analysis • study ne flux from reactor dominated by 51Cr : ~ 10-3 (prelim.) • study possible nuclear transitions e.g. 73Ge* decays by 2g’s separated by t1/2=4.6 ms CsI(Tl) [186 kg] : • attempt measurement of Standard Model s(nee-)  sin2qw at MeV range Prototype ULE-HPGe [5 g] : • threshold < 300 eV  ~ 100 eV • explore potentials on nN coherent scattering & CDM

  42. Reactor Neutrino Interaction Cross-Sections P2: SM (ne) > 2 MeV P1: MM (ne) 1-100 keV P3+: Coh. (nN) < 1 keV

  43. Period-2 CsI(Tl) Array : 186 kg, 93 crystals Single Crystal QL Vs QR (Raw Data) Z = 0 cm Z =40 cm 208Tl 40K 137Cs Region of Interest for SMs(ne)

  44. “Ultra-Low-Energy” HPGe Prototype • mass 5 g ; can be constructed in multi-array form • threshold <100 eV after modest PSD • background measurement on-site Nov 03 • study appl. in nN coherent scattering and Dark Matter searches

  45. ULE-HPGe Prototype Results PSD Cut Threshold ~ 100 eV Threshold < 100 eV Signal Band

  46. R&D Projects • Explore New Detectors Scenarios (LEn, CDM …) • other crystal scintillators • ultra low energy HPGe [ O(100 eV) threshold ] • CsI(Tl) for Dark Matter Searches CsI(Tl) CDM search @ Korea by KIMS Coll. • Upgrading FADCs (+ FPGA etc. capabilities…..) for LEPS@SPring8 • Trace Radio-purity with AMS( Accelerator Mass Spectrometry)  1st goal : sensitivity of 10-14 g/g in 40K • Sono-LuminescenceProject (inter-disciplinary)

  47. Also ………. • Geographically possible for medium baseline experiment : • Easy reach from city • Access to Plant established • Road tunnel at 2 km • 100 m rock overburden Contacts with International Team

  48. TEXONO STATUS • TEXONO Collaboration:  Built-Up and Growing • Kuo-Sheng Neutrino Lab.: Established & Operational ※Modular & Flexible Design Physics Data Taking since June 01 ※Unique HPGe Low Energy Data ※ Bkg Level ~ Underground CDM Expt. • Results published on mn (Gn) Other analyses under way • Period-II DAQ Improved HPGe Conf. 186 kg CsI(Tl) [s(ne) …] study potentials for scoh(nN) …… • Diversified R&D Program in parallel

  49. Summary & Outlook • Neutrinos are important but strange objects history of n physics full of surprises ! • Strong evidenceS of massive n’s & finite mixings Physics Beyond the Standard Model ! • More experiments & projects coming up EVEN MORE EXCITEMENT ! • TEXONO is also a (modest) part of it Tremendous Pleasure & Pressure !

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