occasional meanderings in physics' brave new world

Name:
Location: New Zealand

Marni D. Sheppeard

## Wednesday, May 28, 2008

### Neutrino08 Day 3a

M. Sorel spoke next about the MIPP and HARP hadron production facilities. HARP is currently looking at a factor of 2 reduction in the 16% muon neutrino normalisation uncertainty from $\pi^{+}$ production.

S. Zeller then discussed low E neutrino cross sections at a range of experiments, including MINERvA, which plans to take data in 2009 using He, C, Fe and Pb targets. For K2K, new charge current $\pi^{0}$ results indicate
$\frac{\sigma_{CC}}{\sigma_{QE}} = 0.306 \pm 0.023 \pm 0.02$
which is 40% higher than Monte Carlo predictions. For the new CC $\pi^{+}$ result of $0.734$ see 0805.0186.

A very nice outline of QE scattering was given along with a new K2K Carbon12 estimate for axial mass of
$M_{A} = 1.144 \pm 0.077 \pm 0.08$ GeV
The MiniBooNE result for this was $1.23 \pm 0.20$ GeV (PRL 100 (2008) 032301). Statistics for this result are so good that they did a 2D distribution analysis, for which they quote a $\chi^{2}$ of 45/53 (at 77%). There is apparently 'stunning agreement' across phase space with the oscillation data. Note that modern estimates of $M_{A}$ all tend to give higher values than expected. Is the mass absorbing some nuclear effect, or what?

SciBooNE is performing as expected, having taken $0.99 \times 10^{20}$ POT for 21431 events, 16% pure CC. Some preliminary results were (very quickly) shown. Charge current $\pi^{+}$ seen at high E do not show up. Theorists?