Updated results from the appearance searches for nu(mu) --> nu(tau) and nu(e) --> nu(tau) oscillations in the full NOMAD data sample are reported. The increased data and the use of more refined kinematic schemes for the nu(tau) CC selection allow a significant improvement of the overall sensitivity. The "blind analysis" of both the deep-inelastic and the low multiplicity samples yields no evidence for an oscillation signal. In the two-family oscillation scenario, this sets a 90% C.L. region in the sin(2)2 theta(mu tau) - Delta m(2) plane which includes sin(2)2 theta(mu tau) < 4.4 X 10(-4) at large Delta m(2) and Delta m(2) < 0.8 eV(2)/c(4) at sin(2)2 theta(mu tau) = 1. The corresponding contour in the nu(e) --> nu(tau) oscillation hypothesis results in sin(2)2 theta(e tau) < 2.2 X 10(-2) at large Delta m(2) and Delta m(2) < 6.5 eV(2)/c(4) at sin(2)2 theta(e tau) = 1.
Updated results from the ντ appearance search in NOMAD
MARTELLI, FILIPPO;VELTRI, MICHELE;
2000
Abstract
Updated results from the appearance searches for nu(mu) --> nu(tau) and nu(e) --> nu(tau) oscillations in the full NOMAD data sample are reported. The increased data and the use of more refined kinematic schemes for the nu(tau) CC selection allow a significant improvement of the overall sensitivity. The "blind analysis" of both the deep-inelastic and the low multiplicity samples yields no evidence for an oscillation signal. In the two-family oscillation scenario, this sets a 90% C.L. region in the sin(2)2 theta(mu tau) - Delta m(2) plane which includes sin(2)2 theta(mu tau) < 4.4 X 10(-4) at large Delta m(2) and Delta m(2) < 0.8 eV(2)/c(4) at sin(2)2 theta(mu tau) = 1. The corresponding contour in the nu(e) --> nu(tau) oscillation hypothesis results in sin(2)2 theta(e tau) < 2.2 X 10(-2) at large Delta m(2) and Delta m(2) < 6.5 eV(2)/c(4) at sin(2)2 theta(e tau) = 1.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
