117059077
Results from K2K and status of T2K
Results from the K2K experiment and status of the T2K experiment are reported. 1. Results from the K2K experiment The K2K experiment[1] is the first long-baseline neutrino oscillation experimentwith a distance of hundred kilometers andusing an acceleratorbased neutrino beam. It started in 1999 and ended in November, 2004. The main purpose of K2K is to confirm muon neutrino oscillation claimed by the Super-Kamiokande experiment[2] using an artificial neutrino beam. Because the details of the experiment are already described in other articles[1, 3], only updated numbers and figures are presented in Table 1. Some comments that were not covered in my previous articles[3] are itemized below: − After the accident of Super-Kamiokande in November, 2001, the total number of PMTs in Super-Kamiokande was reduced to be about one half. The K2K experiment of this period was named K2K-II. In this period, the lead-glass counters of the front detector were replaced by a SciBar detector[1], a fully active fine-grained detector made of 14848 strips of extruded scintillator read out by wavelength-shifting fibers. There is no essential change in the oscillation analysis. − A possible νe appearance signal from νe ↔ νμ oscillation was also searched[4]. From tight e-like event selection, only one candidate remains, where the expected background is 1.63. The expected signal is 1 ∼ 2 events if the parameter region around the CHOOZ limit[5] is assumed. The 90% C.L. upper limit on sin 2θeμ (=12 sin 2 2θ13) is 0.18 for ∆m2 = 2.8× 10−3eV2. This limit has no impact on our present knowledge on the oscillation parameters because of the poor statistics (see Section 3.1). ‡ E-mail address: yuichi.oyama@kek.jp; URL: http://www-nu.kek.jp/ oyama ∗ Talk at International Conference on New Trends in High-Energy Physics (Crimea2005), Yalta, Ukraine, September 10-17, 2005
16605725
K2K (KEK to Kamioka) neutrino-oscillation experiment at KEK-PS
A long-baseline neutrino-oscillation experiment using a well-defined neutrino beam is in preparation at KEK. Neutrinos generated at KEK will be detected by the Super-kamiokande detector 250 km away. The design of the neutrino beam line, beam monitors and detector are briefly presented. The sensitivities for neutrino oscillations are also discussed.
14625424
Anisotropy of the primary cosmic-ray flux in Super-Kamiokande
A first-ever 2-dimensional celestial map of primary cosmic-ray flux was obtained from 2.10x10^8 cosmic-ray muons accumulated in 1662.0 days of Super-Kamiokande. The celestial map indicates an (0.104 \pm 0.020)% excess region in the constellation of Taurus and a -(0.094 \pm 0.014)% deficit region toward Virgo. Interpretations of this anisotropy are discussed.
118442499
Present Status of the K2K Experiment
New results from the K2K (KEK to Kamioka) long-baseline neutrino-oscillation experiment is presented.
121739509
Atmospheric Neutrino Background and Pion Nuclear Effect for KAMIOKA Nucleon Decay Experiment
The main source of background for nucleon decay experiments is the interaction of atmospheric neutrinos in the detector. To estimate this background a Monte Carlo program was developed, which simulates the neutrino interactions and the nuclear effects of secondary pions. The program reproduced existing neutrino data as well as global features of the contained events in the KAMIOKA nucleon decay experiment. Neutrino induced background for nucleon decay was then calculated.
119511324
Current Status of the K2K Experiment
Current status of the K2K (KEK to Kamioka) long-baseline neutrino-oscillation experiment is presented.
15903450
Deep Extragalactic Surveys around the Ecliptic Poles with AKARI (ASTRO-F)
AKARI (formerly ASTRO-F) is an infrared space telescope designed for an all-sky survey at 10-180 µm, and deep pointed surveys of selected areas at 2-180 µm. The deep pointed surveys with AKARI will significantly advance our understanding of galaxy evolution, the structure formation of the Universe, the nature of the buried AGNs, and the cosmic infrared background. Here we describe the important characteristics of the AKARI mission: the orbit, and the attitude control system, and investigate the optimum survey area based on the updated pre-flight sensitivities of