Application of neutrino spectrometry 1 Solar neutrino detection

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 1987 A remnant

Study of solar neutrinos Big amount of electron neutrino is produced during pp and CNO cycle 4 p → 4 He + 2 e+ + 2νe Present information: 1) Solar neutrino are produced 2) Significant difference between prediction and observation → sign of new physics (neutrino oscillations) Neutrino fluence [cm-2 s-1] Future information based on neutrinos: 1) 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 energy [Me. V] Spectrum of solar neutrinos calculated by J. Bahcalla

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 Me. V. Energy spectrum → Fermi distribution k. T ≈ 3 – 6 Me. V Supernovae SN 1987 A Distance of 150 000 light years Present information (supernovae SN 1987 A): 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 Relation between neutrino Properties of hot and very dense matter energy and time of its arrival Observation of supernovae shielded by galactic matter

Cosmic ray neutrinos Primary component: particle with high energy (up to ~ 1011 Ge. V – present accelerators ~ 104 Ge. V), 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

Results of AMANDA detector Nebula NGC 6543 (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

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 Δm 2 = |m 12 – m 22| [e. V 2], L – distance at meters [m] Eν – neutrino energy [Me. V] Probability, that at distance d we find anti νμ is and anti νe : d

Oscillation were observed: 1) Solar neutrinos (large distances) 2) Nuclear power station 3) Secondary cosmic rays 4) Accelerator - detector Solar neutrinos Experiment EMIN [Me. V] Experiment [SNU] Model [SNU] Exp. /Mod. Kamiokande 7 0. 47(2) 1. 00(17) 0. 47 Homestake (Cl) 0. 8 2. 56(23) 7. 7(12) 0. 33 GALEX 0. 2 74(7) 129(8) 0. 57 SAGE 0. 2 75(8) 129(8) 0. 58 Derivation of Δm 2 (νe ↔ νμ) Δm 2 ~ 7(4)∙ 10 -5 e. V 2 Relation between Δm 2 and θ values Experiment GALEX

Measurement of reactor antineutrino oscillation Detection of antineutrino νμ ↔ νe Δm 2 =7, 9(6)∙ 10 -5 e. V 2 Time variation given by changes of nuclear reactors power Oscillation data measured using different reactors Detector KAMLAND Measured and simulated spectrum of antineutrinos

Secondary cosmic ray Angular distribution of cosmic neutrinos from Kamiokande νe - isotropic distribution νμ - úbytek νμ ↔ ντ Δm 2 =(1 -3)∙ 10 -3 e. V 2 Accelerator – detector experiment K 2 K experiment – observation of 108 neutrinos – prediction of 151(11) neutrinos Neutrino spectrum detected by K 2 K experiment The best fit with oscillation Region of suitable Δm 2 a sin 22θ values

Geoneutrinos Project Kam. LAND – study of antineutrino oscillations by means of reactor Antineutrinos from 238 U and 232 Th decay Decay of 238 U and 232 Th impeachable for hot earth core and plate tectonics First observation – project Kam. LAND: 4 – 40 detected geoantineutrinos Agree with model predictions about amount of uranium and thorium in earth crust and core 13 C(α, n)16 O reactor antineutrinos background geoantineutrinos Antineutrinos from project Kam. LAND (corrected on oscillations) 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

Relict neutrinos are produced during early stage of universe t ~ 1 s (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 Me. V 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 Ge. V (1012 – 1016 Ge. V – real value depends on neutrino mass) → resonce increasing of interactions with relict neutrinos occurs → minimum in the energy spectrum of high energy of cosmic neutrinos