
We have studied the strangenesschanging antineutrinoinduced reactions (v) over bar (l)p > l(+)phi B, with phi B = K()p, (K) over bar (0)n, pi(0)Lambda, pi(0)Sigma(0), eta Lambda, eta Sigma(0), pi(+)Sigma(), pi()Sigma(+), K+Xi(), and K0 Xi(0), using a chiral unitary approach. These ten coupled channels are allowed to interact strongly, using a kernel derived from the chiral Lagrangians. This interaction generates two Lambda(1405) poles, leading to a clear single peak in the pi Sigma invariant mass distributions. At backward scattering angles in the centerofmass frame, (nu) over bar (mu)p > mu(+)pi(0)Sigma(0) is dominated by the Lambda(1405) state at around 1420 MeV while the lighter state becomes relevant as the angle decreases, leading to an asymmetric line shape. In addition, there are substantial differences in the shape of pi Sigma invariant mass distributions for the three charge channels. If observed, these differences would provide valuable information on a claimed isospin I = 1, strangeness S = 1 baryonic state around 1400 MeV. Integrated cross sections have been obtained for the pi Sigma and (K) over barN channels and the impact of unitarization in the results has been investigated. The number of events with Lambda(1405) excitation in (nu) over bar μp collisions in the recent antineutrino run at the Main Injector Experiment for nuA (MINER nu A) has also been obtained. We find that this reaction channel is relevant enough to be investigated experimentally and to be taken into account in the simulation models of future experiments with antineutrino beams.
