No Arabic abstract
This paper presents the results of oscillation analysis in K2K experiment. The results show indications of neutrino oscillation and give a new constraint on the oscillation parameters. The difference of neutrino masses squared $Delta m^2$ lies between 1.5 and 3.9$times10^{-3} {rm eV}^2$ at $sin^2 2theta=1$ with the confidence level of 90%. In addition to these results, a brief overview of future long-baseline neutrino experiment in Japan, JHF-$ u$ experiment, is also given in this paper.
The KLOE detector at the DA$Phi$NE $phi$-factory has been operating in two periods from 2001 to 2006 and from 2014 to 2018 collecting a large sample of $phi$-meson decays. This allowed to perform precision measurements and studies of fundamental symmetries, and searches of New Physics phenomena. In this overview, the results of KLOE and KLOE-2 Collaborations are presented. The most recent results from the KLOE experiment are discussed, covering: the measurement of the running fine-structure constant $alpha_{em}$, the Dalitz plot measurement of $eta rightarrow pi^+pi^-pi^0$, the search of a U boson, tests of discrete symmetries and quantum decoherence.
The $ uebar$ flux and spectrum have been measured at a distance of about 800 m from the reactors of the Palo Verde Nuclear Generating Station using a segmented Gd-loaded liquid scintillator detector. Correlated positron-neutron events from the reaction $ uebar$p$to$e^+n were recorded for a period of 200 d including 55 d with one of the three reactors off for refueling. Backgrounds were accounted for by making use of the reactor-on and reactor-off cycles, and also with a novel technique based on the difference between signal and background under reversal of the e^+ and n portions of the events. A detailed description of the detector calibration, background subtraction, and data analysis is presented here. Results from the experiment show no evidence for neutrino oscillations. $ uebartobar u_x$ oscillations were excluded at 90% CL for $dm>1.12times10^{-3}$ eV^2 for full mixing, and $sinq>0.21$ for large $dm$. These results support the conclusion that the observed atmospheric neutrino oscillations does not involve $ u_{rm e}$.
The TRIUMF Weak Interaction Symmetry Test (TWIST) experiment was designed to test the standard model at high precision in the purely leptonic decay of polarized muons. A general four-fermion interaction model is used to describe the muon decay. TWIST measures three of the four muon decay parameters of this model, $rho$, $delta$ and $P_{mu}^{pi} xi$, from the shape of the momentum-angle spectrum. The results of this model independent approach are compared to the standard model predictions and used to constrain new physics. Our collaboration has finalized the blind analysis of the final experimental data taken in 2006 and 2007. This analysis mostly reached our goal of a precision of an order of magnitude improvement over the pre-TWIST measurements.
The analysis and results are presented from the complete data set recorded at Palo Verde between September 1998 and July 2000. In the experiment, the $ uebar$ interaction rate has been measured at a distance of 750 and 890 m from the reactors of the Palo Verde Nuclear Generating Station for a total of 350 days, including 108 days with one of the three reactors off for refueling. Backgrounds were determined by (a) the $swap$ technique based on the difference between signal and background under reversal of the positron and neutron parts of the correlated event and (b) making use of the conventional reactor-on and reactor-off cycles. There is no evidence for neutrino oscillation and the mode $ uebartobar u_x$ was excluded at 90% CL for $dm>1.1times10^{-3}$ eV$^2$ at full mixing, and $sinq>0.17$ at large $dm$.
A muon range detector (MRD) has been constructed as a near detector for the KEK-to-Kamioka long-baseline neutrino experiment (K2K). It monitors the neutrino beam properties at the near site by measuring the energy, angle and production point of muons produced by charged-current neutrino interaction. The detector has been working stably since the start of the K2K experiment.