The interference pattern or composition varies as it travels through space. The electron neutrino turns into superimposition of three mass states. At the end of the journey weak interaction reveals the true identity as different flavor (one of the tau-neutrino, muon-neutrino or electron-neutrino) according to the interference pattern at the time of detection.įigure 02 shows what happens after the beta decay of a neutron in outer space. This case of missing neutrinos can be explained if the neutrinos possess mass in such a way that these "mass states" superimpose each other during free flight. The count inevitably has a shortfall of muon-neutrinos with a ratio of about 1.3 to 1. Other observations involved the impact of cosmic ray on nuclei in the atmosphere, it is expected that the ratio of muon-neutrinos to electron-neutrinos is 2 to 1. These observations have always counted fewer neutrinos than predictions from the best models. For more than 30 years, scientists have been capturing electron-neutrinos generated by nuclear fusion in the Sun. However, it seems that something is missing. They are similar to each other except carrying different mass. Later on it is found that there are three flavors of neutrino - the electron neutrino, muon neutrino, and tau neutrino. Otherwise, it is not a “fundamental” property for particles with mass. For massless particle, helicity is an intrinsic property its value is fixed in all reference frames. Helicity is defined as the component of spin along the direction of motion, it is always perpendicular to the orbital angular momentum if there is any participating in weak interaction. Superluminal Neutrino (see Neutrino as Tachyon)īack in the 1950s it was generally believed that neutrino has no mass and it exists only as a left-handed neutrino or right-handed anti-neutrino (see Figure 01, and Weyl spinor). A Toy Model for Neutrino Oscillation (2019) "A novel technique for the measurement of the electron neutrino cross section". Large angle muons and positrons from kaon decays ( K + → μ + ν μ : Cite journal requires |journal= ( help) Kaons and pions are momentum and charge selected in a short transfer line by means of dipole and quadrupole magnets and are focused in a collimated beam into an instrumented decay tube. The proposed facility is being studied taking into account the energies of currently available proton drivers: 400 GeV ( CERN SPS), 120 GeV ( FNAL Main Injector), 30 GeV ( J-PARC Main Ring). Mesons (essentially pions and kaons) are produced in the interactions of accelerated protons with a Beryllium or Graphite target. In ENUBET, neutrinos are produced by focusing mesons in a narrow band beam towards an instrumented decay tunnel, where charged leptons produced in association with neutrinos by mesons' decay can be monitored at single particle level. A new generation of cross-section experiment is therefore needed to overcome these limitations with new techniques or high precision beams, as ENUBET. Current neutrino cross-section experiments are limited by large uncertainties in the neutrino flux. This probability is measured counting the number of interacting neutrinos divided by the flux of incoming neutrinos. the probability for a neutrino to interact in the detector. The experiments that will measure CP violation need a very precise knowledge of the neutrino cross-sections, i.e. In quantum field theory, this effect is described by a violation of the CP symmetry in particle physics. This effect points toward a difference in the behavior of matter and antimatter. DUNE and Hyper-Kamiokande are aimed at discovering CP violation in neutrinos observing a small difference between the probability of a muon-neutrino to oscillate into an electron-neutrino and the probability of a muon-antineutrino to oscillate into an electron-antineutrino. Interest in these types of high precision neutrino beams has grown significantly in the last ten years, especially after the start of the construction of the DUNE and Hyper-Kamiokande detectors. The Enhanced NeUtrino BEams from kaon Tagging or ENUBET is an ERC funded project that aims at producing an artificial neutrino beam in which the flavor, flux and energy of the produced neutrinos are known with unprecedented precision.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |