Application of neutrino spectrometry

1. Application of neutrino spectrometry 1) Solar neutrino detection 2) Supernovae neutrino detection 3) Cosmic and atmospheric neutrino detection 4) Neutrino oscillation studies 5) Detection of neutrinos from Earth interior 6) Relict neutrino detection Sun from SOHO probe Neutrino detector ANTARES at Mediterranean See Supernovae 1987A remnant

2. Study of solar neutrinos Big amount of electron neutrino is produced during pp and CNO cycle 4p → 4He + 2e+ + 2νe • Present information: • 1) Solar neutrino are produced • 2) Significant difference between prediction • and observation → sign of new physics • (neutrino oscillations) • Future information based on neutrinos: • Accurate sizes of Sun central regions, • where fusion reactions runs • 2) Present picture of Sun interior (photons • travel through sun long time) – • prediction of future Sun behavior • 3) Temperature of central regions of Sun • 4) Ratios between different types of fusion • reactions Sun from SOHO probe Neutrino fluence [cm-2s-1] neutrino energy[MeV] Spectrum of solar neutrinos calculated by J. Bahcalla

3. Study of supernovae neutrinos Final stage of massive star – collapse and supernovae explosion Large part of energy releases in the form of neutrino during two phases: 1) Beginning – during neutron creation by electron capture only electron neutrino: p + e- → n + νe 2) All types of neutrino and antineutrino with statistical distribution (1/6 on one type) with mean energy 10 – 15 MeV. Energy spectrum → Fermi distribution kT ≈ 3 – 6 MeV Supernovae SN1987A Distance of 150 000 light years Present information (supernovae SN1987A): Confirmation of neutrino creation Ordinary agreement with assumption Closeness of neutrino velocity to light velocity, limitation on neutrino rest mass Determination of limitation on neutrino lifetime Possible future information (we are waiting on near supernovae): Confirmation of models of supernovae explosion Properties of hot and very dense matter Observation of supernovae shielded by galactic matter Relation between neutrino energy and time of its arrival

4. Cosmic ray neutrinos Primary component:particle with high energy (up to ~ 1011 GeV – present accelerators ~ 104 GeV), protons and nuclei are the biggest part, also neutrinos and antineutrins νe, νμ a ντ are present. Isotropic distribution – they come from all directions Origin: more distant undistinguishable sources (supernovae, active galaxy nuclei, collapsing objects …) Secondary component: Collisions of cosmic ray particles and nuclei with atmospheric nuclei → many hadrons → many mesons π among them: π + → μ+ + νμ π - → μ- + anti -νμ └→ e+ + νe + anti-νμ └→ e- + anti-νe + νμ Intensive source of neutrino and antineutrino νμ and νe ratio between numbers of νμ and νe is R(νμ/νe) = 2 also intensive source of muons Atmospheric shower Possible future information: Information about processes and sources with big amount of energy (gamma burst sources) Not distorted data about region covered by dense clouds of matter Neutrino path is not influenced by magnetic fields and they are not absorbed Study of nature of cosmic phenomena

5. Results of AMANDA detector Nebula NGC6543 (Hubble telescope) Active galaxy Spectrum of neutrinos agrees with prediction for atmospheric neutrinos Distribution of directions, from which single neutrinos came – random distribution – Point like sources were not found – also correlation with gamma bursts were not found

6. Studies of neutrino oscillation Neutrino wave function is mixture of different states (νe, νμ, ντ) . As example – oscillation of anti νμ and anti νe: Probability of muon antineutrino to electron is: where Δm2 = |m12 – m22| [eV2], L – distance at meters [m] Eν – neutrino energy [MeV] Probability, that at distance d we find anti νμisand anti νe: d

7. Oscillation were observed: 1) Solar neutrinos (large distances) 2) Nuclear power station 3) Secondary cosmic rays 4) Accelerator - detector Solar neutrinos Derivation of Δm2 (νe ↔ νμ) Δm2~ 7(4)∙10-5 eV2 Relation between Δm2 and θ values Experiment GALEX

8. Measurement of reactor antineutrino oscillation Detection of antineutrino νμ ↔ νe Δm2 =7,9(6)∙10-5 eV2 Time variation given by changes of nuclear reactors power Measured and simulated spectrum of antineutrinos Oscillation data measured using different reactors Detector KAMLAND

9. The best fit with oscillation Secondary cosmic ray Angular distribution of cosmic neutrinos from Kamiokande νe - isotropic distribution νμ- úbytek νμ ↔ ντ Δm2 =(1-3)∙10-3 eV2 Accelerator – detector experiment K2K experiment – observation of 108 neutrinos – prediction of 151(11) neutrinos Neutrino spectrum detected by K2Kexperiment Region of suitable Δm2 a sin22θ values

10. 13C(α,n)16O reactor antineutrinos background geoantineutrinos Geoneutrinos Project KamLAND – study of antineutrino oscillations by means of reactor Antineutrinos from 238U and 232Th decay Decay of 238U and 232Th impeachable for hot earth core and plate tectonics First observation – project KamLAND: 4 – 40 detected geoantineutrinos Agree with model predictions about amount of uranium and thorium in earth crust and core Thermal flow: Total ~ 40 TW radionuclides ~ 19 TW (U,Th,K) Larger detector farer from reactors makes possible study of antineutrinos with such accuracy, which is needed for some geophysical models exclusion Antineutrinos from project KamLAND (corrected on oscillations)

11. Relict neutrinos are produced during early stage of universe t ~ 1s (t ~ 300 000 years for relict photons), present temperature of neutrinos is T ≈ 1,9 K (photons T ≈ 3,1 K) For energies E > 1 MeV different types of neutrinos are in the equilibrium: where i = e, μ, τ For lower energies neutrinos do not interact with rest of matter – freeze out occurs Very low energy → very big problems with detection Possibility of detection (only hypothetical up to now): 1) Processes, which do not need energy – neutrino initiates beta decay of nucleus: νe + n → p+ + e- Electron energy > decay energy of nucleus → peak in the electron spectrum under end of Fermi graph (very weak).Measurement as during neutrino mass studies – necessity to find proper nuclei and transitions, number of decays initiated by relict neutrinos was should be not negligible. Necessity to improve parameters of electron spectrometers. Problems with the natural background. 2) Interaction of accelerated particles – energy is delivered by accelerated particles. Choice of proper parameters for sufficient probability of interaction – problem with background, necessity of high intensity and stability of accelerator beam. 3) Interaction of very energetic neutrinos of cosmic rays: such Eν, that centre of mass energy is equal to rest mass of Z boson during collision with relict neutrino MZ = 100 GeV (1012 – 1016 GeV – real value depends on neutrino mass) → resonce increasing of interactions with relict neutrinos occurs → minimum in the energy spectrum of highenergy of cosmic neutrinos