1. Introduction on Astroparticle Physics Research options

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1 Research options Large variety of topics in astro physics and particle physics Cosmic rays (sources, production and acceleration mechanisms) Stability of matter or proton decay (GUTs) Solar neutrinos (the centre of the Sun) Supernova neutrinos (explosion mechanism) Diffuse (or relic) supernova neutrinos (birth rate of start) Geoneutrinos (inner part of the Earth) Neutrino properties (reactors, beams) (MH, CP,...) LAGUNA LBNO (next-generation detectors) Search for dark matter Double beta decay (neutrino mass) APP 2013 UOulu 1.1

2 High-energy cosmic rays: General High energy: limit at the transition of direct and indirect measurements, approximately ev Flux: power-low spectrum (power index 3) = steeply decreasing with increasing energy Three features at the energy spectrum knee at ev (reason not known) ankle at ev (extra-galactic sources) GZK-cutoff at ev (interactions with CMB) Motivation: find out cosmic-ray sources, their origin, acceleration mechanisms, propagation in the space Experimental study requires large-area detector arrays Severe source of background for most of the astroparticle experiments (muon rate 150 Hz m 2 ) = deep underground laboratories APP 2013 UOulu 1.2

3 High-energy cosmic rays: Energy spectrum & Acceleration energies knee GZK ankle APP 2013 UOulu 1.3

4 High-energy cosmic rays: Air showers At high energies cosmic-ray experiments are based on the detection of air showers 30 km Determination of mass and energy of the primary particle requires the full knowledge of the nuclear reactions and particle production in the air shower All cross sections could not have been measured by acceleration experiments Large shower-by-shower fluctuations in the height of the first interaction APP 2013 UOulu 1.4

5 High-energy cosmic rays: Experiments: KASCADE Grande (Germany), knee ankle KArlsruhe Shower Core and Array DEtector eē+ γ γ π 0 p n p π + π - Simultaneous measurement of electromagnetic, muonic, hadronic shower components µ - γ γ e + e - e - e + e + e - γ γ π 0 π - µ - e - π 0 p n p p π - π - n n π + µ + APP 2013 UOulu 1.5 T. Antoni et al, Nucl. Instr. & Meth. A 513 (2004) 490

6 High-energy cosmic rays: Experiments: Pierre Auger Observatory (Argentina), GZK-region Surface Array 1600 detector stations 1.5 km spacing 3000 km 2 CLF APP 2013 UOulu 1.6 Fluorescence Detectors 4 Telescope enclosures 6 Telescopes per enclosure 24 Telescopes total 5

7 Proton decay Predicted by (some) Grand Unified Theories (GUTs) = unification of forces at high energies ( ev), or short distances ( cm) Unification energy too high for current and near-future accelerators = Proton decay provides a low-energy possibility to study GUTs Important in physics theories Current lower limit for the life time (SK): τ p > years Next-generation experiments (LAGUNA) can extend the limit up to years one decay per year = atoms in the detector = mass 100 kton (LAGUNA-size detectors) Decay modes p K + + ν (liquid scintillation or liquid argon, SUSY favoured, τ p y) p e + + π 0 (Water Cherenkov, liquid argon, τ p y)... APP 2013 UOulu 1.7

8 Neutrino sources Sun Energy production APP 2013 UOulu 1.8

9 Neutrino sources Sun Solar neutrino spectrum APP 2013 UOulu 1.9

10 Neutrino sources Sun Solar neutrinos Energy production: proton-proton chain (ppi, ppii, ppiii) Neutrinos are produced in the centre of the Sun escape immediately = ideal way to study interiors of the Sun Delicate competition between ppi, ppii, and ppiii is sensitive to many details of solar physics, as the core temperature the radial temperatue profile the metallicity Experimentally, for example 7 Be ν-flux = ppii-cycle 8 B ν-flux = ppiii-cycle pp-ν-flux = ppi-cycle + ppii-cycle + ppiii-cycle CNO-ν-flux important for early stellar evolution Accuracy of 1 5% should be achieved = possible with the future experiments (LAGUNA) APP 2013 UOulu 1.10

11 Neutrino sources Sun Solar neutrino detectors Borexino (Gran Sasso, Italy, depth 1.2 km) APP 2013 UOulu 1.11

12 Neutrino sources Supernovae Explosion rate in our galaxy: few per decade part is seen optically, all with neutrinos Measured neutrino spectrum from supernova provides information from the explosion mechanism itself it is not known (cannot be exploded in computers) neutrino pulse 20 sec, all flavours Observed once: SN1987A approximately 25 events (by three detectors) in currently running detectors: several hundreds ν-events in next-generation detectors (LAGUNA): several thousands ν-events Important and interesting as with proton decay, not reasonable to built SN-ν detector alone Diffuse (relic) supernova neutrinos neutrinos from all supernova explosions in the past low-energy ν: Eν 0 20 MeV (redshifted!) would provide information on the birth rate of stars APP 2013 UOulu 1.12

13 Neutrino sources Supernovae SN1987A APP 2013 UOulu 1.13

14 Neutrino sources Supernovae SN1987A ν-spectrum APP 2013 UOulu 1.14

15 LAGUNA An option in Pyhäsalmi APP 2013 UOulu 1.15

16 Neutrino sources Earth Geo-neutrinos Steven Dye GeoScience 2010 APP 2013 UOulu 1.16

17 Background General Astroparticle physics experiments Proton decay: in maximum few events per year Neutrinos: small cross section results in low event rate, but varies a lot depending on the source Dark matter search: in maximum few events per year Double beta decay: in maximum few events per year Background sources Cosmic rays (µ-flux 150 Hz m 2 ) = detectors deep underground protons, neutrons and electrons stop in thin layer of matter muons may penetrate deep underground Natural radioactivity in materials = clean materials (and liquids) Nuclear reactors only way is to go far away APP 2013 UOulu 1.17

18 Background Shielding from cosmic-ray muons Cosmic-ray induced muon flux measured at the Pyhäsalmi mine on several various depths T. Enqvist et al., NIM A554 (2005) 286 mwe = metre water equivalent = density of rock in [g/cm 3 ] the depth in [m] 90-level: 1 Hz m 2 (EMMA-level, 75 m underground) 1390-level: 0.5µ / h m 2 WIPP Boulby LNGS LAGUNA APP 2013 UOulu 1.18

19 Background Radioactivity Example: Borexino 7 Be neutrino spectrum APP 2013 UOulu 1.19

20 WMAP Amount of Dark Matter APP 2013 UOulu 1.20

21 WMAP Amount of Dark Matter APP 2013 UOulu 1.21