#### Title:

The Golden Measurement at a Neutrino Factory

PHD

Glasgow U.

13-11-2007

#### Description:

Neutrinos have provided the first evidence for physics beyond the Standard Model of Particle Physics. We now know that neutrinos have mass, and that they undergo coherent oscillations between neutrino flavours. The next phase in the study of neutrino oscillations is the determination that the smallest of the mixing angles (named theta_13) is non-zero and that neutrinos can undergo CP violations, just like quarks do. CP violations for neutrinos would be a major discovery and could be the explanation for the matter-antimatter asymmetry of the universe via a mechanism called letogenesis that could have occurred in the early universe.

The most promising facility for the discovery of CP violation in neutrinos is the so-called Neutrino Factory in which neutrinos are generated from the decay of muons. The "Golden" measurement at the neutrino factory relies on the measurements of nu_e to nu_mu oscillations by observing a muon (from a neutrino interaction) in a detector far away from the neutrino source (2500-7500 km) that has the wrong sign with respect to the muons that would be expected from the beam of neutrinos. The wrong-sign muon is the main signature for neutrino oscillations and any differences between neutrino and antineutrino oscillations would be evidence for CP violations.

There is a world-wide effort towards the construction of a Neutrino Factory by the year 2020 and to define the optimal machine and detector parameters to measure CP violations at a Neutrino Factory by the year 2012. You will aid in the design of a Neutrino Factory detector by developing the simulation of a Magnetised Iron Neutrino Detector (MIND) of about 50 kton, which is currently the baseline detector option at a Neutrino Factory. You will develop simulation tools to carry out a detailed study of the capabilities of MIND and you will carry out the wrong-sign muon analysis to determine the sensitivity of MIND to CP violation. As part of the study, you will determine the optimal segmentation and granularity of the detector, the signal efficiency from a full pattern recognition and reconstruction of the events within MIND, and the background rejection from charge misidentification, and from other backgrounds that can mimic the field wrong-sign; muon signature (pion, kaon and charm ! decay).

A common problem is that the determination of the mixing parameters once a CP asymmetry has been observed, has an eight-fold ambiguity (up to eight different regions of the parameter space can fit the same experimental data). The use of a second detector at a different baseline can resolve these ambiguities. Other detector concepts, such as a Totally Active Scintillator Detector (TASD), or an emulsion detector to measure nu_e to nu_tau oscillations (the Silver channel) can remove these ambiguities. You will then perform an optimisation of the capabilities of a Neutrino Factory by studying a combination of two baselines, with detectors able to measure both the 'golden' and 'silver' channels to have a full unambiguous determination of all the oscillation parameters. Your analysis will be included in the Conceptual Design Report for a Neutrino Factory to be ready by 2012.

You will work within the Glasgow neutrino group of two research staff and two PhD students. Your will have a chance to present your work at international Neutrino Factory meetings around the world (Europe, UK, Asia, USA).

Contact:

Letters of Reference should be sent to: p.soler@physics.gla.ac.uk