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The disk-loaded structures (DLS) in the muon LINAC are under development for the J-PARC muon g–2/EDM experiment. Four DLSs with an accelerating gradient of 20 MV/m take charge of muon acceleration from 40 MeV to 212 MeV, which corresponds to 70% to 94% of the speed of light. The quasi-constant gradient type TM01-2π/3 mode DLSs with gradually varying disk spacing was designed and it was confirmed that the cumulative phase slip due to the mismatch between muon and phase velocity can be suppressed to less than 2 degrees at the frequency of 2592 MHz. In addition, the optimum synchronous phase and the lattice were investigated to satisfy the requirements of the total emittance less than 1.5π mm mrad and the momentum spread less than 0.1% in RMS.

Negative muonium atom (μ+e-e-, Mu-) has unique features stimulating potential interesting for several scientific fields. Since its discovery in late 1980's in vacuum, it has been discussed that the production efficiency would be improved using a low-work function material. C12A7 was a well-known insulator as a constituent of alumina cement, but was recently confirmed to exhibit electric conductivity by electron doping. The C12A7 electride has relatively low-work function (2.9 eV). In this paper, the negative muonium production measurement with several materials including a C12A7 electride film will be presented.

Abstract This paper introduces a new approach to measure the muon magnetic moment anomaly $a_{\\mu} = (g-2)/2$ and the muon electric dipole moment (EDM) $d_{\\mu}$ at the J-PARC muon facility. The goal of our experiment is to measure $a_{\\mu}$ and $d_{\\mu}$ using an independent method with a factor of 10 lower muon momentum, and a factor of 20 smaller diameter storage-ring solenoid compared with previous and ongoing muon $g-2$ experiments with unprecedented quality of the storage magnetic field. Additional significant differences from the present experimental method include a factor of 1000 smaller transverse emittance of the muon beam (reaccelerated thermal muon beam), its efficient vertical injection into the solenoid, and tracking each decay positron from muon decay to obtain its momentum vector. The precision goal for $a_{\\mu}$ is a statistical uncertainty of 450 parts per billion (ppb), similar to the present experimental uncertainty, and a systematic uncertainty less than 70 ppb. The goal for EDM is a sensitivity of $1.5\\times 10^{-21}~e\\cdot\\mbox{cm}$.

The Belle experiment, running at the KEKB e+e− asymmetric energy collider during the first decade of the century, achieved its original objective of precisely measuring differences between particles and antiparticles in the B system. After collecting 1000 fb−1 of data at various Υ resonances, Belle also obtained the many other physics results described in this article.

We report the first measurement of the inclusive e+e- → bb̄ → D^(±)_(s) X and e+e- → bb̄ → D0 / D̅⁰ X cross sections in the energy range from 10.63 to 11.02 GeV. Based on these results, we determine σ(e+e- → B_(s)⁰B̅_(s)⁰ X) and σ(e+e- → BB̅ X) in the same energy range. We measure the fraction of B_(s)⁰ events at Υ(10860) to be fs = (22.0_(-2.1)^(+2.0))%. We determine also the ratio of the B_(s)⁰ inclusive branching fractions 𝓑(B_(s)⁰ → D0/ D̅⁰X)/𝓑(B_(s)⁰ → D_(s)^(±)X) = 0.416 ± 0.018 ± 0.092. The results are obtained using the data collected with the Belle detector at the KEKB asymmetric-energy e+e- collider.

We report the first measurement of the inclusive e ⁺ e ⁻ → bb̅ → D_(s)^(±) X and e ⁺ e ⁻ → bb̅ → D ⁰ / D̅⁰ X cross sections in the energy range from 10.63 to 11.02 GeV. Based on these results, we determine σ(e ⁺ e ⁻ → B_(s)⁰B̅_(s)⁰ X) and σ(e ⁺ e ⁻ → BB̅ X) in the same energy range. We measure the fraction of B_(s)⁰ events at Υ(10860) to be f _(s)= ( 22.0_(-2.1)^(+2.0) )%. We determine also the ratio of the B_(s)⁰ inclusive branching fractions 𝓑 ( B_(s)⁰ → D ⁰ / D̅⁰ X)/ 𝓑 ( B_(s)⁰ → D_(s)^(±) X) = 0.416 ± 0.018 ± 0.092. The results are obtained using the data collected with the Belle detector at the KEKB asymmetric-energy e ⁺ e ⁻collider.[graphic not available: see fulltext]

We report the first measurement of the inclusive e + e − →$$ b\\overline{b} $$b b ¯ →$$ {D}_s^{\\pm } $$D s ± X and e + e − →$$ b\\overline{b} $$b b ¯ → D 0 /$$ {\\overline{D}}^0 $$D ¯ 0 X cross sections in the energy range from 10 . 63 to 11 . 02 GeV. Based on these results, we determine σ ( e + e − →$$ {B}_s^0{\\overline{B}}_s^0 $$B s 0 B ¯ s 0 X ) and σ ( e + e − →$$ B\\overline{B} $$B B ¯ X ) in the same energy range. We measure the fraction of$$ {B}_s^0 $$B s 0 events at Υ(10860) to be f s = ($$ {22.0}_{-2.1}^{+2.0} $$22.0 − 2.1 + 2.0 )%. We determine also the ratio of the$$ {B}_s^0 $$B s 0 inclusive branching fractions$$ \\mathcal{B} $$B ($$ {B}_s^0 $$B s 0 → D 0 /$$ {\\overline{D}}^0 $$D ¯ 0 X ) /$$ \\mathcal{B} $$B ($$ {B}_s^0 $$B s 0 →$$ {D}_s^{\\pm } $$D s ± X ) = 0 . 416 ± 0 . 018 ± 0 . 092. The results are obtained using the data collected with the Belle detector at the KEKB asymmetric-energy e + e − collider.

We present the first model-independent measurement of the CKM unitarity triangle angle ϕ3 using B±→ D(KS0\\[ {K}_{\\mathrm{S}}^0 \\]π+π−π0) K± decays, where D indicates either a D0 or D¯\\[ \\overline{D} \\]0 meson. Measurements of the strong-phase difference of the D →KS0\\[ {K}_{\\mathrm{S}}^0 \\]π+π−π0 amplitude obtained from CLEO-c data are used as input. This analysis is based on the full Belle data set of 772 × 106BB¯\\[ \\overline{B} \\] events collected at the Υ(4S) resonance. We obtain ϕ3 = (5.7−8.8+10.2\\[ {5.7}_{-8.8}^{+10.2} \\]±3.5±5.7)° and the suppressed amplitude ratio rB = 0.323±0.147±0.023±0.051. Here the first uncertainty is statistical, the second is the experimental systematic, and the third is due to the precision of the strong-phase parameters measured from CLEO-c data. The 95% confidence interval on ϕ3 is (−29.7, 109.5)°, which is consistent with the current world average.

Using a data sample of 980 fb − 1 collected with the Belle detector at the KEKB asymmetric-energy e + e − collider, we study for the first time the singly Cabibbo-suppressed decays$$ {\\Omega}_c^0\\to {\\Xi}^{-}{\\pi}^{+} $$Ω c 0 → Ξ − π + and Ω − K + and the doubly Cabibbo-suppressed decay$$ {\\Omega}_c^0\\to {\\Xi}^{-}{K}^{+} $$Ω c 0 → Ξ − K + . Evidence for an$$ {\\Omega}_c^0 $$Ω c 0 signal in the$$ {\\Omega}_c^0 $$Ω c 0 → Ξ − π + mode is reported with a significance of 4 . 5 σ including systematic uncertainties. The ratio of branching fractions to the normalization mode$$ {\\Omega}_c^0 $$Ω c 0 → Ω − π + is measured to be$$ \\mathcal{B}\\left({\\Omega}_c^0\\to {\\Xi}^{-}{\\pi}^{+}\\right)/\\mathcal{B}\\left({\\Omega}_c^0\\to {\\Omega}^{-}{\\pi}^{+}\\right)=0.253\\pm 0.052\\left(\\textrm{stat}.\\right)\\pm 0.030\\left(\\textrm{syst}.\\right). $$B Ω c 0 → Ξ − π + / B Ω c 0 → Ω − π + = 0.253 ± 0.052 stat . ± 0.030 syst . . No significant signals of$$ {\\Omega}_c^0\\to {\\Xi}^{-}{K}^{+} $$Ω c 0 → Ξ − K + and Ω − K + modes are found. The upper limits at 90% confidence level on ratios of branching fractions are determined to be$$ \\mathcal{B}\\left({\\Omega}_c^0\\to {\\Xi}^{-}{K}^{+}\\right)/\\mathcal{B}\\left({\\Omega}_c^0\\to {\\Omega}^{-}{\\pi}^{+}\\right)<0.070 $$B Ω c 0 → Ξ − K + / B Ω c 0 → Ω − π + < 0.070 and$$ \\mathcal{B}\\left({\\Omega}_c^0\\to {\\Omega}^{-}{K}^{+}\\right)/\\mathcal{B}\\left({\\Omega}_c^0\\to {\\Omega}^{-}{\\pi}^{+}\\right)<0.29. $$B Ω c 0 → Ω − K + / B Ω c 0 → Ω − π + < 0.29 .

Using a data sample of 980 fb-1 collected with the Belle detector at the KEKB asymmetric-energy e+e- collider, we study for the first time the singly Cabibbo-suppressed decays Ω0c → Ξ¯π+ and Ω¯K+ and the doubly Cabibbo-suppressed decay Ω0c → Ξ¯ K+. Evidence for an Ω0c signal in the Ω0c → Ξ¯π+ mode is reported with a significance of 4.5σ including systematic uncertainties.