Determination Of Neutrino Fluxes Research Articles

Linear vs non-linear QCD evolution in the neutrino-nucleon cross section

Evidence for an extraterrestrial flux of ultra-high-energy neutrinos, in the order of PeV, has opened a new era in Neutrino Astronomy. An essential ingredient for the determination of neutrino fluxes from the number of observed events is the precise knowledge of the neutrino-nucleon cross section. In this work, based on [1], we present a quantitative study of σ νN in the neutrino energy range 10 4 E ν 14 GeV within two transversal QCD approaches: NLO DGLAP evolution using different sets of PDFs and BK small- x evolution with running coupling and kinematical corrections. Further, we translate this theoretical uncertainty into upper bounds for the ultra-high-energy neutrino flux for different experiments.

NA61 data for T2K flux calculations

The approved T2K neutrino oscillation physics program requires a 5% neutrino flux determination and the ability to extrapolate the neutrino flux from near to far detector with a precision of 3%. The NA61 experiment at the CERN North Area measures hadron production over all the phase space needed by the T2K experiment and aims at producing a measurement of particle yields with a precision of 5% or better for pions and 10% for Kaons.

Taking a germanium detector down into the shaft of the thallium mine: What is the relevance to the solar neutrino flux determination via 205Pb?

We propose two reactions induced by environmental gamma-rays which may eventually have the same input and output nuclear channels as the neutrino capture itself and whose yields therefore must be estimated in background evaluation. From here there follows the need to know the gamma-ray spectra at the excavation site.

Measurement of low energy neutrino absorption probability in thallium 205

A major aspect of the P-P solar neutrino flux determination using 205Tl is the very difficult problem of experimentally demonstrating the neutrino reaction cross section with about 10% accuracy. Based on an idea of P. Kienle, such measurements now become possible. Moreover, the proposed measurements of weak interaction rates are in the isotopic states of interest; hence they will be much more readily acceptable than would indirect measurements via strong or electromagnetic interactions or theoretical calculations. One will soon be able to completely strip the electrons from atomic 205Tl and to maintain the bare nucleus in this state in the heavy ion storage ring to be built at GSI Darmstadt. This nucleus can decay by emitting a beta-minus particle into the bound K-level of the daughter 82 205 Pb 1 2 − 81+ ion as the only energetically open decay channel (plus, of course, an antineut This single channel beta decay explores the same nuclear wave functions of initial and final states as does the neutrino capture in atomic 205Tl, and thus its probability or rate is governed by the same nuclear matrix elements that affect both weak interactions: 81 205 Tl 1 2 + 81+→ 82 205 Pb 1 2 − 81++ ν ν 81 205 Tl 1 2 + 0→ 82 205 Pb 1 2 − 1++ e − Measuring the rate of accumulation of 205Pb 81+ ions in the circulating beam of 205Tl 81+ ions gives directly the cross section of reaction (b). The calculations of the expected rates under realistic experimental conditions will be shown to be very favorable for the measurement, e.g., ∼10 4 ions per hour in a 100 mA beam. The great sensitivity of the rate to the 205Pb- 205Tl mass difference will appear (12%/keV), showing the need to materially improve the uncertainty in this value, and several experiments will be proposed. A special calibration experiment to verify the method and check the theoretical calculations will be suggested. Finally the neutrino cross section calculation based on the observed rate of reaction (a) will be shown. Demonstrating bound state beta decay may be the first verification of the theory of this very important process that influences beta decay rates of several isotopes in stellar interiors, e.g., 187Re, that play important roles in geologic and cosmologic dating and nucleosynthesis.