Neutrino interactions at few MeV: results from Borexino at Gran Sasso

Borexino, at the I.N.F.N. Gran Sasso Underground Laboratory in Italy, is an experiment designed to detect, in real-time, low energy solar neutrinos. After a brief presentation of the Borexino physics and detector, we illustrate some recent results and their physics implications. Borexino perspectives are also discussed

Measurement of the CP violating asymmetry amplitude sin 2beta

We present results on time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurements use a data sample of about 88 million Y(4S) --> B Bbar decays collected between 1999 and 2002 with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We study events in which one neutral B meson is fully reconstructed in a final state containing a charmonium meson and the other B meson is determined to be either a B0 or B0bar from its decay products. The amplitude of the CP-violating asymmetry, which in the Standard Model is proportional to sin2beta, is derived from the decay-time distributions in such events. We measure sin2beta = 0.741 +/- 0.067 (stat) +/- 0.034 (syst) and |lambda| = 0.948 +/- 0.051 (stat) +/- 0.030 (syst). The magnitude of lambda is consistent with unity, in agreement with the Standard Model expectation of no direct CP violation in these modes.Comment: 7 pages, 2 postscript figures, submitted to PR