Proc. Neutrino Astrophysics - MPP Theory Group

More documents

Recommendations

Info

32 Table 1: Neutrino event rates in SNO (including detection efficiency). SSM refers to the event rate per year for 8 B solar neutrinos assuming the standard solar model [4] and the small angle MSW solution [3]. SN refers to a type II supernova at a distance of 10 kpc (the center of the galaxy). Neutrino reaction SSM SN Charged Current (CC): νe + d → p + p + e − 3000 80 Neutral Current (NC): νx + d → p + n + νx 2500 300 Electron Scattering (ES): νe,x + e − → νe,x + e − 400 20 Anti-neutrino CC in D2O: ¯νe + d → n + n + e + 0 70 Anti-neutrino CC in H2O: ¯νe + p → n + e + 0 350 iii) 3 He Counters: An array of 3 He proportional counters [5] (5 cm diameter tubes of 800 m total length) placed vertically in the D2O in a square grid of 1m spacing, gives a 42% chance of neutron capture on 3 He. The energy and rise-time of the signals are used to separate n-capture (2,000 per year) from internal alpha and beta backgrounds. The dominant background for all these NC detection methods will probably come from photodisintegration of deuterium which produces free neutrons that are indistinguishable from NC neutrons. Thus, the detector components have been carefully selected for extremely low levels of thorium and uranium chain contamination so that the photodisintegration rate is small compared with the NC rate. This small residual photodisintegration rate must be measured, in order to subtract its contribution to the neutron capture signal. Several methods have been developed for this purpose: i) radiochemical extraction and counting of 228 Th, 226 Ra, 224 Ra, 222 Rn and 212 Pb, ii) analysis of low energy signals seen by the PMT array, iii) delayed coincidences between signals seen by the PMT array, and iv) prompt and delayed coincidences between signals seen by the PMTs and signals in the 3 He proportional counters. References [1] G.T. Ewan et al., Sudbury Neutrino Observatory Proposal, SNO 87-12 (1987). [2] H.H. Chen, Phys. Rev. Lett. 55 (1985) 1534. [3] N. Hata and P. Langacker, Phys. Rev. D 48 (1993) 2937. [4] J.N. Bahcall and M.H. Pinsonneault, Rev. Mod. Phys. 64 (1994) 885. [5] T.J. Bowles et al., Construction of an Array of Neutral-Current Detectors for the Sudbury Neutrino Observatory, SNO internal report.
BOREXINO L. Oberauer (for the Borexino Collaboration) Technische Universität München, Physik Department E15, 85747 Garching, Germany and Sonderforschungsbereich 375 Teilchen-Astrophysik Physics Goals and Neutrino Detection with Borexino The aim of the solar neutrino experiment Borexino is to measure in real time the solar neutrino flux with low energy threshold at high statistics, and energy resolving via pure leptonic neutrino electron scattering ν + e → ν + e. Motivation for Borexino comes from the long standing solar neutrino puzzle. Data analysis of the existing experiments leads to the assumption of severe suppression of the solar 7 Bebranch, which probably cannot be explained by modifications of the standard astrophysical model of the sun. The monoenergetic 7 Be-neutrinos give rise to a compton like recoil spectrum in Borexino. Its edge will be at 660 keV, significantly higher than the aimed energy threshold of ca. 250 keV. Thus 7 Be-neutrino detection is very efficient in Borexino. Assuming validity of the standard model a counting rate for 7 Be-neutrinos, which would consist in this case purely as νe, of roughly 55/day in Borexino is expected. In scenarios of total neutrino flavour conversion (i.e. for neutrino mass differences ∆m 2 ≈ 10 −6 −10 −5 eV 2 ) a reduced flux of approximately 12/day would be measured due to the lower cross section of νµ,τ scattering, which occurs only via neutral current interaction. In case of vacuum oscillations (i.e. for neutrino mass differences ∆m 2 ≈ 10 −10 eV 2 ) Borexino would see a distinct time dependent periodical neutrino signal due to the seasonal eccentricity of the earth’s orbit around the sun. For neutrino mass differences in the range of ∆m 2 ≈ 10 −7 eV 2 and for large mixing Borexino should see a ‘day/night’ effect due to electron neutrino regeneration during the path through the earth. Borexino also can serve for additional projects in neutrino physics. Search for a magnetic moment can be performed by means of terrestrial neutrino sources by investigating the electron recoil shape at low momentum transfer. Via the inverse beta-decay ¯νe + p → e + + n Borexino can look for signals from geophysical neutrinos as well as for neutrinos emitted by european nuclear power plants. The latter would serve as a long baseline neutrino oscillation experiment probing the so-called large mixing angle solution for the solar neutrino problem. The Detector and Background Considerations The detector is shielded successively from outer radioactivity by means of an onion-like structure. Here the adjacent inner layer serves as shielding and has to provide an increased purity in terms of internal radioactivity. Borexino is placed in hall C of the underground laboratory at Gran Sasso, Italy. An overburden of ca. 3500 m.w.e. suppresses the cosmic muon flux to roughly 1/m 2 . The outer part of the detector consists of a steel tank with 18 m in height and diameter. Inside this ‘external’ tank a stainless steel sphere will support 2200 phototubes on the inside and 200 tubes at the outside. Most of the tubes inside the sphere will be equipped with light guides in order to increase the geometrical coverage and hence the energy resolution. Between external 33
Page 1 and 2: arXiv:astro-ph/9801320v1 30 Jan 199
Page 3: Preface This was the fourth worksho
Page 6 and 7: vi S.J. Hardy Quasilinear Diffusion
Page 8 and 9: viii
Page 11 and 12: History of Neutrino Physics: Pauli
Page 13 and 14: Brief an Oskar Klein, Stockholm, vo
Page 15 and 16: Recent observations with the Hubble
Page 17 and 18: MACHO sample of ∼100,000 light cu
Page 19: Solar Neutrinos
Page 22 and 23: 14 In the depth range where an abun
Page 24 and 25: 16 as follows: (1) All the detector
Page 26 and 27: 18 [3] J.N. Bahcall and H.A. Bethe,
Page 28 and 29: 20 the opacity has a very slowly ch
Page 30 and 31: 22 Status of the Radiochemical Gall
Page 32 and 33: 24 known true source activity. The
Page 34 and 35: 26 Solar Neutrino Observation with
Page 36 and 37: 28 Events/day/kton/bin 0.3 0.25 0.2
Page 38 and 39: 30 log(Δm 2 (eV 2 log(Δm )) 2 (eV
Page 42 and 43: 34 tank and sphere high purity wate
Page 44 and 45: 36 Measurements of Low Energy Nucle
Page 46 and 47: 38 Figure 1: The S(E) factor of 3 H
Page 48 and 49: 40 Solar Neutrinos: Where We Are an
Page 50 and 51: 42 [9] B. Pontecorvo, Chalk River R
Page 52 and 53: 44 Figure 2: The difference between
Page 55 and 56: Phenomenology of Supernova Explosio
Page 57 and 58: Figure 2: Theoretical classificatio
Page 59 and 60: Supernova Rates Bruno Leibundgut Eu
Page 61 and 62: galaxies, however, and the statisti
Page 63 and 64: Figure 1: The motions of pulsars re
Page 65 and 66: Convection in Newly Born Neutron St
Page 67 and 68: a b Figure 2: Panel a shows the rec
Page 69 and 70: ference). The angular variations of
Page 71 and 72: Figure 1: Neutrino luminosity and e
Page 73 and 74: [9] G.S. Bisnovatyi-Kogan, Astron.
Page 75 and 76: and the mass-to-luminosity ratio of
Page 77 and 78: Figure 1: Time variation of superno
Page 79 and 80: Figure 3: Energy spectra of the sup
Page 81 and 82: Supernova Neutrino Opacities G.G. R
Page 83 and 84: Quasilinear Diffusion of Neutrinos
Page 85 and 86: Assuming a saturated thermal distri
Page 87 and 88: Anisotropic Neutrino Propagation in
Page 89 and 90: So far the damping rate corresponds
Page 91 and 92:
Cherenkov Radiation by Massless Neu
Page 93 and 94:
on ω so that they are well approxi
Page 95:
2 2 / meff,e m eff 1.0 0.5 0.0 elec
Page 99 and 100:
Gamma-Ray Burst Observations D.H. H
Page 101 and 102:
Figure 1: The cumulative distributi
Page 103 and 104:
[7] Lilly, S., in Critical Dialogue
Page 105 and 106:
) Phase Transitions in Neutron Star
Page 107 and 108:
after the collapse began (nb., no e
Page 109 and 110:
Models of Coalescing Neutron Stars
Page 111 and 112:
Figure 2: Contour plots of the mass
Page 113 and 114:
From our torus models we find that
Page 115:
High-Energy Neutrinos
Page 118 and 119:
110 in gamma-rays. However, the acc
Page 120 and 121:
112 Atmospheric Muons and Neutrinos
Page 122 and 123:
114 Today, however, charm productio
Page 124 and 125:
116 Atmospheric Neutrinos in Super-
Page 126 and 127:
118 number of events 300 200 100 (a
Page 128 and 129:
120 Acknowledgements D.K. is suppor
Page 130 and 131:
122 Key signatures for νµ nucleon
Page 132 and 133:
124 (a.u) 0.5 0.4 0.3 0.2 0.1 0 0 1
Page 134 and 135:
126 However, in order to operate th
Page 136 and 137:
128 could be gravitationally captur
Page 138 and 139:
130 Ground-Based Observation of Gam
Page 140 and 141:
132 Figure 2: Sensitivities in unit
Page 142 and 143:
134 Crab flux Figure 4: Gamma-ray f
Page 144 and 145:
136
Page 147 and 148:
Helium Absorption and Cosmic Reioni
Page 149 and 150:
Non-Standard Big Bang Nucleosynthes
Page 151 and 152:
) Non-standard Neutrino Properties
Page 153 and 154:
some heating of the plasma. In cont
Page 155 and 156:
Big Bang Nucleosynthesis With Small
Page 157 and 158:
Neutrinos and Structure Formation i
Page 159 and 160:
Photon and Neutrino Backgrounds The
Page 161 and 162:
The (photon) temperature at aeq is
Page 163 and 164:
spectrum has therefore changed to 1
Page 165 and 166:
Figure 4: Growth of structure in CD
Page 167:
Future Prospects
Page 170 and 171:
162 Figure 1: Calorimetric β − s
Page 172 and 173:
164 References [1] F. Gatti: Procee
Page 174 and 175:
166 The frequency of Galactic super
Page 176 and 177:
168 Table 1: Comparison of proposed
Page 178 and 179:
170 Neutrinos in Astrophysics José
Page 180 and 181:
172 N eq 7 6.5 6 5.5 5 4.5 4 3.5 3
Page 182 and 183:
174 Figure 4: SN 1987A bounds on FC
Page 184 and 185:
176 [5] A. Joshipura and J. W. F. V
Page 186 and 187:
178 Some Neutrino Events of the 21s
Page 188 and 189:
180 2099: Relic Neutrinos And last
Page 190 and 191:
182
Page 192 and 193:
184 Tuesday, Oct. 21: Supernova Neu
Page 194 and 195:
186 Michael Altmann Technische Univ
Page 196 and 197:
188 Paolo Gondolo Max-Planck-Instit
Page 198 and 199:
190 Patrizia Meunier Max-Planck-Ins
Page 200 and 201:
192 Torsten Soldner Technische Univ
Page 202 and 203:
194 A Experimental Particle Physics
Page 204:
196 C Astrophysics and Cosmology C1
show all

Proc. Neutrino Astrophysics - MPP Theory Group

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?