摘要 :
The Double Chooz is a reactor neutrino experiment which measures the last unknown neutrino mixing angle θ_(13). The Double Chooz experiment uses two identical detectors placed at sites far and near from Chooz reactor cores. The d...
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The Double Chooz is a reactor neutrino experiment which measures the last unknown neutrino mixing angle θ_(13). The Double Chooz experiment uses two identical detectors placed at sites far and near from Chooz reactor cores. The detector uses 390 low-background and high performance 10-in. Photo-Multiplier Tubes (PMTs) to detect scintillation light from gadolinium loaded liquid scintillator. In order to test and characterize the PMTs and to tune operation parameter, we developed two types of PMT test system and evaluated 400 PMTs before installation. Those PMTs fulfilled our requirements and half of them were installed in the far detector in 2009 and physics data have been successfully taken since 2011.
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摘要 :
We have developed an in-lab energy-filtered X-ray photoemission electron microscopy (EXPEEM) combining a high-brilliance X-ray source and a new Wien filter-type energy analyzer, which can accept photoelectrons in a wide angle. To ...
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We have developed an in-lab energy-filtered X-ray photoemission electron microscopy (EXPEEM) combining a high-brilliance X-ray source and a new Wien filter-type energy analyzer, which can accept photoelectrons in a wide angle. To obtain high energy resolution, we enlarged the inner diameter of the filter and reduced aberrations of an analyzer using multipole electrodes and air-core coils. We obtained an energy-filtered image of photoelectrons.
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摘要 :
A distinct peak is observed in the π~± Ψ' invariant mass distribution near 4.43 GeV in B → Kπ~± Ψ' decays. A fit using a Breit-Wigner resonance shape yields a peak mass and width of M = 4433 ± 4(stat) ± 2(syst) MeV and Γ...
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A distinct peak is observed in the π~± Ψ' invariant mass distribution near 4.43 GeV in B → Kπ~± Ψ' decays. A fit using a Breit-Wigner resonance shape yields a peak mass and width of M = 4433 ± 4(stat) ± 2(syst) MeV and Γ = 45_(-13)~(+18)(stat)_(-13)~(+30)(syst) MeV. The product branching fraction is determined to be 'B(B~0 → K~(-+)Z~±(4430)) × 'B(Z~±(4430) → π~± Ψ' = (4.1 ± 1.0(stat) ± 1.4(syst)) × 10~(-5), where Z~±(4430) is used to denote the observed structure. The statistical significance of the observed peak is 6.5σ. These results are obtained from a 605 fb~(-1) data sample that contains 657 × 10~6 BB pairs collected near the Y(4S) resonance with the Belle detector at the KEKB asymmetric energy e~+e~- collider.
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