HEP experiments in Japan: The Next Generation

The HEP experiment in Japan is now stepping into next phase. J-PARC, which is a newly-built high intensity proton synchrotron facility, has started the operation recently. A new long-baseline neutrino experiment T2K is now at the commissioning stage utilizing the beam. In parallel, the upgrade of KEKB/Belle, a new generation B-factory experiment at KEK, is about to start. The accelerator will be upgraded to SuperKEKB whose luminosity is expected to be about 50 times higher. The detector is also upgraded to Belle II to keep up with the drastic increase. In this talk, a detailed review is given for these new experiments with some coverage of the readout and DAQ technologies

Photon polarization entanglement induced by biexciton: experimental evidence for violation of Bell's inequality

We have investigated the polarization entanglement between photon pairs generated from a biexciton in a CuCl single crystal via resonant hyper parametric scattering. The pulses of a high repetition pump are seen to provide improved statistical accuracy and the ability to test Bell's inequality. Our results clearly violate the inequality and thus manifest the quantum entanglement and nonlocality of the photon pairs. We also analyzed the quantum state of our photon pairs using quantum state tomography.Comment: 4 pages, 5 figure

Measurements of time dependent CP asymmetry in B→VVB \to VV decays with BELLE

A study of CP violation in $B\to J/\psi K^*(K_S^0\pi^0)$ decays by time dependent angular analysis is discussed. Status of time independent analyses for other $B\to VV$ decays is also reported. The data used for the analyses are taken with the Belle detector at KEK.Comment: 4 pages, 3 figures, Proceeding of the talk in parallel session (CP-3-5) at ICHEP2002, Amsterdam, Netherland, 24-31 July (2002

Anti-correlated Optical Flux and Polarization Variability in BL Lac

We present the results of photometric (V band) and polarimetric observations of the blazar BL Lac during 2008--2010 using TRISPEC attached to the KANATA 1.5-m telescope in Japan. The data reveal a great deal of variability ranging from days to months with detection of strong variations in fractional polarization. The V band flux strongly anti-correlates with the degree of polarization during the first of two observing seasons but not during the second. The direction of the electric vector, however, remained roughly constant during all our observations. These results are consistent with a model with at least two emission regions being present, with the more variable component having a polarization direction nearly perpendicular to that of the relatively quiescent region so that a rising flux can produce a decline in degree of polarization. We also computed models involving helical jet structures and single transverse shocks in jets and show that they might also be able to agree with the anti-correlations between flux and fractional polarization.Comment: % pages, 4 figures. Accepted for publication in Astrophysical Journal Letter

Quantum diffraction and interference of spatially correlated photon pairs and its Fourier-optical analysis

We present one- and two-photon diffraction and interference experiments involving parametric down-converted photon pairs. By controlling the divergence of the pump beam in parametric down-conversion, the diffraction-interference pattern produced by an object changes from a quantum (perfectly correlated) case to a classical (uncorrelated) one. The observed diffraction and interference patterns are accurately reproduced by Fourier-optical analysis taking into account the quantum spatial correlation. We show that the relation between the spatial correlation and the object size plays a crucial role in the formation of both one- and two-photon diffraction-interference patterns.Comment: 10 pages, 13 figures, rev.