1. Alain Blondel, 24 July 2006 NA49/T2K phone Meeting NA49/T2K Introduction to the physics case Preamble: since I have not myself run any code or simulations of performance what follows aims at bringing out arguments to build up the physics case for the T2K NA49 proposal.

2. Alain Blondel, 24 July 2006 NA49/T2K phone Meeting philosophy: envisage this experiment as if it would never be done again ==> get from CERN assurance that either we collect a sufficient amount of data in the first couple of years, (preferred solution) or that the apparatus is preserved in a good enough state From HARP experience these measurements are everything but easy. Do the measurement to a quality level that allows sufficient precision to the end of the programme

3. Alain Blondel, 24 July 2006 NA49/T2K phone Meeting Standard Oscillation framework --Four different phases/precision levels 1. Precision measurements of disappearance channel --> Atmospheric parameters:  m 2 23, sin 2  23 Here we are mostly concerned about the far/near ratio for CC   events useful plots: Far/near for non-oscillated   and sensitivity to K/pi ratio, Pion average mom., average p T or model. 2. Discovery or confirmation of the   e channel --> order of magnitude of  13 need good measurement of (at least) the K/pi ratio since this affects the near/far ratio for e background and    background useful plots: Far/near for e background and    background 3. Precise measurement of P(   e ) for comparison with e.g. D-CHOOZ for  CP or NOvA for matter effects (statistical error will depend on  13 ) Useful plots: all of the above +? 4. Ultimate measure: A CP in T2HK or T2KK etc… need a precise measurement of the neutrino and antineutrino fluxes for numu and nue, with perhaps one overall normalization missing. From the HyperK plots 2% systematics already bites into the stat. precision? some antineutrino plots? Non Standard Oscillation: ex: disappearance measurements in the NC channel check serile neutrinos etc… useful plots: Far/near for non-oscillated    e ?

4. Alain Blondel, 24 July 2006 NA49/T2K phone Meeting from Hiraide

5. Alain Blondel, 24 July 2006 NA49/T2K phone Meeting from Fechner