0000000001119641
AUTHOR
Ana María Tornero López
Measurement of the quasi-elastic axial vector mass in neutrino-oxygen interactions
The weak nucleon axial-vector form factor for quasielastic interactions is determined using neutrino interaction data from the K2K Scintillating Fiber detector in the neutrino beam at KEK. More than 12 000 events are analyzed, of which half are charged-current quasielastic interactions nu(mu)n ->mu(-)p occurring primarily in oxygen nuclei. We use a relativistic Fermi gas model for oxygen and assume the form factor is approximately a dipole with one parameter, the axial-vector mass M-A, and fit to the shape of the distribution of the square of the momentum transfer from the nucleon to the nucleus. Our best fit result for M-A=1.20 +/- 0.12 GeV. Furthermore, this analysis includes updated vect…
Experimental study of the atmospheric neutrino backgrounds for p -> e(+)pi(0) searches in water Cherenkov detectors
The atmospheric neutrino background for proton decay via p -> e(+)pi(0) in ring imaging water Cherenkov detectors is studied with an artificial accelerator neutrino beam for the first time. In total, 3.14x10(5) neutrino events corresponding to about 10 megaton-years of atmospheric neutrino interactions were collected by a 1000 ton water Cherenkov detector (KT). The KT charged-current single pi(0) production data are well reproduced by simulation programs of neutrino and secondary hadronic interactions used in the Super-Kamiokande (SK) proton decay search. The obtained p -> e(+)pi(0) background rate by the KT data for SK from the atmospheric neutrinos whose energies are below 3 GeV is 1.63(-…
Measurement of the production cross-section of positive pions in p-Al collisions at 12.9 GeV/c
A precision measurement of the double-differential production cross-section, d(2)sigma(pi+)/dpd Omega for pions of positive charge. performed in the HARP experiment is presented. The incident particles are protons of 12.9 GeV/c momentum impinging on an aluminium target of 5% nuclear interaction length. The measurement of this cross-section has a direct application to the calculation of the neutrino flux of the K2K experiment. After cuts, 210000 secondary tracks reconstructed in the forward spectrometer were used in this analysis. The results are given for secondaries within a momentum range from 0.75 to 6.5 GeV/c. and within an angular range from 30 mrad to 2 10 mrad. The absolute normaliza…
Improved search for nu(mu)->nu(e) oscillation in a long-baseline accelerator experiment
We performed an improved search for nu(mu)->nu(e) oscillation with the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment, using the full data sample of 9.2x10(19) protons on target. No evidence for a nu(e) appearance signal was found, and we set bounds on the nu(mu)->nu(e) oscillation parameters. At Delta m(2)=2.8x10(-3) eV(2), the best-fit value of the K2K nu(mu) disappearance analysis, we set an upper limit of sin(2)2 theta(mu e)< 0.13 at a 90% confidence level.