Long base-line neutrino experiments analyses.

The neutrinos are most abound elementary particles in the Universe yet they are least understood. Measurement of basic features of neutrinos will allow better understanding of evolution of starts, galaxies and might be part of the explanation why the Universe is made of matter with apparent lack of anti-matter.

There are three know types of neutrinos: electron neutrino, muon neutrino and tau neutrino and they are always produce in pair with electron, muon or tau particle correspondently. Neutrino and their partners are called leptons. For a last few decades many experiments showed that although neutrinos are produced with associated changed lepton they can change their nature (oscillate) from one type to another. Neutrino oscillations are measured as an excess of one type of neutrinos or/and a deficit of another type. In the T2K experiment a beam on muon neutrinos (with about 1% contamination of electron neutrinos) are created at J-PARC accelerator facility on the east cost of Japan and directed to a large (50kton pure water) far detector on the west coast about 250 km from the source. In this detector we count what fraction on muon neutrinos was transform to electron neutrino and what fraction survive the travel. The main uncertainties for that measurement come from the mis-identification of electron produced in the electron neutrino interaction. To better understand the background we use another detector (ND280) placed close to the source of neutrinos to measure composition of the neutrino beam. The ND280 is complex detector which can measure neutrino interactions with great precision.

We propose to measure cross sections (probability that interaction occurs) for neutrino interaction channels with production of two neutral pions and one neutral pion and any changed pion. We will measure both charged current (with production of charged lepton) and neutral current interactions (with neutrino surviving the interactions but with different momentum). The precise measurement of those channels will help us better understand the axial part of the proton and neutron structure, which is not accessible by scattering of electron on nucleons.

Neutrinos masses are very small when compared to other elementary particles but it is not zero. It was shown that only left-handed neutrinos (projection of their spin is opposite to the direction of their momentum) take part in the weak interactions. However if neutrinos have magnetic moment it is possible to exchange a photon (at a loop level) with change of neutrino into a right-handed one. Such interaction can be detected as an excess of elastic neutrino interactions of the atomic electrons. With a high intensity of the muon neutrino beam from the J-PARC it will be possible to test values of the neutrino magnetic moment below current best limit on muon neutrino magnetic moment.

Another part of the project is to start analyses for the future Long Base-Line Experiment (LBNE). The experiment will start taking data in 2023 and the construction will start at the end of 2017. Untimely this experiment has a capability to measure CP violation (difference between how matter and anti-matter particles interact and decay). We will participate in the data analysis of the 35 ton of Liquid Argon prototype detector which is currently under construction at Fermi National Laboratory close to Chicago, US. The analysis will help to understand detector response to cosmic rays. In addition to the analysis we will build a test stand to test several elements of the LBNE detectors which will be place in the liquid Argon.

The beneficiaries of the research for the T2K experiment are other researcher around the world working on the electron neutrino appearance measurements. Other beneficiaries are the authors of the Monte Carlo generators (e.g. GENIE) as well as theorists who will be able to constrain current theoretical models used by all neutrino oscillation experiments.

The project for the Long Base-Line Experiment (LBNE) will transfer an expertise for the liquid Argon TPC detector technology to the UK.