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H. Kawai

Bio: H. Kawai is an academic researcher from Chiba University. The author has contributed to research in topics: KEKB & Branching fraction. The author has an hindex of 76, co-authored 477 publications receiving 22713 citations. Previous affiliations of H. Kawai include University of Maribor & University of Ljubljana.


Papers
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Journal ArticleDOI
Suyong Choi1, S. L. Olsen, Kazuo Abe, T. Abe  +172 moreInstitutions (46)
TL;DR: In this article, a narrow charmonium-like state produced in the exclusive decay process B+/--->K+/-pi(+)pi(-)J/psi has been observed, which has a mass of 3872.0+/-0.6(stat)+/- 0.5(syst) MeV.
Abstract: We report the observation of a narrow charmoniumlike state produced in the exclusive decay process B+/--->K+/-pi(+)pi(-)J/psi. This state, which decays into pi(+)pi(-)J/psi, has a mass of 3872.0+/-0.6(stat)+/-0.5(syst) MeV, a value that is very near the M(D0)+M(D(*0)) mass threshold. The results are based on an analysis of 152M B-Bmacr; events collected at the Upsilon(4S) resonance in the Belle detector at the KEKB collider. The signal has a statistical significance that is in excess of 10sigma.

1,294 citations

Journal ArticleDOI
TL;DR: The gamman-->K(+)K(-)n reaction on 12C has been studied by measuring both K+ and K- at forward angles and a sharp baryon resonance peak was observed, consistent with an antidecuplet of baryons predicted by the chiral soliton model.
Abstract: The $\ensuremath{\gamma}n\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}n$ reaction on $^{12}\mathrm{C}$ has been studied by measuring both ${K}^{+}$ and ${K}^{\ensuremath{-}}$ at forward angles. A sharp baryon resonance peak was observed at $1.54\ifmmode\pm\else\textpm\fi{}0.01\text{ }\text{ }\mathrm{G}\mathrm{e}\mathrm{V}/{c}^{2}$ with a width smaller than $25\text{ }\text{ }\mathrm{M}\mathrm{e}\mathrm{V}/{c}^{2}$ and a Gaussian significance of $4.6\ensuremath{\sigma}$. The strangeness quantum number ($S$) of the baryon resonance is $+1$. It can be interpreted as a molecular meson-baryon resonance or alternatively as an exotic five-quark state ($uudd\overline{s}$) that decays into a ${K}^{+}$ and a neutron. The resonance is consistent with the lowest member of an antidecuplet of baryons predicted by the chiral soliton model.

691 citations

01 Jan 2005
TL;DR: The AMANDA-II data collected during the period 2000-2003 have been analysed in a search for a diffuse flux of high-energy extra-terrestrial muon neutrinos from the sum of all sources in the Universe as mentioned in this paper.
Abstract: The AMANDA-II data collected during the period 2000–2003 have been analysed in a search for a diffuse flux of high-energy extra-terrestrial muon neutrinos from the sum of all sources in the Universe. With no excess events seen, an upper limit of Eν × dNν/dEν< 7.4×10−8 GeV cm−2 s−1 sr−1was obtained. The sensitivity of the diffuse analysis of IceCube 9 string for 137 days of data is calculated to be Eν × dNν/dEν< 1.3× 10−7 GeV cm−2 s−1 sr−1. No excess events are observed, which confirms the AMANDA-II upper limit.

617 citations

Journal ArticleDOI
Kazuo Abe1, Y. Chao, S. Kobayashi, S. Yanaka  +247 moreInstitutions (1)
TL;DR: The standard model CP violation parameter sin2 phi(1) is measured based on a data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider and it is concluded that the neutral B meson system is observed.
Abstract: We present a measurement of the standard model $\mathrm{CP}$ violation parameter $\mathrm{sin}2{\ensuremath{\varphi}}_{1}$ based on a $29.1{\mathrm{fb}}^{\ensuremath{-}1}$ data sample collected at the $\ensuremath{\Upsilon}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider. One neutral $B$ meson is fully reconstructed as a $J/\ensuremath{\psi}{K}_{S}$, $\ensuremath{\psi}(2S){K}_{S}$, ${\ensuremath{\chi}}_{c1}{K}_{S}$, ${\ensuremath{\eta}}_{c}{K}_{S}$, $J/\ensuremath{\psi}{K}_{L}$, or $J/\ensuremath{\psi}{K}^{*0}$ decay and the flavor of the accompanying $B$ meson is identified from its decay products. From the asymmetry in the distribution of the time intervals between the two $B$ meson decay points, we determine $\mathrm{sin}2{\ensuremath{\varphi}}_{1}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.99\ifmmode\pm\else\textpm\fi{}0.14(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.06(\mathrm{syst})$. We conclude that we have observed $\mathrm{CP}$ violation in the neutral $B$ meson system.

576 citations

Journal Article
Kazuo Abe, R. Abe1, T. Abe2, Byoung Sup Ahn3  +199 moreInstitutions (45)
TL;DR: The B meson decay modes B -->Dpp; and B-->D(*)pp; have been studied using 29.4 fb(-1) of data collected with the Belle detector at KEKB using the corresponding upper limits at 90% C.L. are presented.
Abstract: The B meson decay modes B → Dpp and B → D*pp have been studied using 29.4 fb - 1 of data collected with the Belle detector at KEKB. The B 0 → D 0 pp and B 0 → D* 0 pp decays have been observed for the first time with branching fractions B(B 0 → D 0 pp) = (1.18 ′ 0.15 ′ 0.16) X 10 - 4 and B(B 0 → D* 0 pp) = (1.20 + 0 . 3 3 - 0 . 2 9 ′ 0.21) X 10 - 4 . No signal has been found for the B + → D + pp and B + → D* + pp decay modes, and the corresponding upper limits at 90% C.L. are presented.

441 citations


Cited by
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Journal ArticleDOI
01 Apr 1988-Nature
TL;DR: In this paper, a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) is presented.
Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

9,929 citations

Journal ArticleDOI
TL;DR: The current status of particle dark matter, including experimental evidence and theoretical motivations, including direct and indirect detection techniques, is discussed in this paper. But the authors focus on neutralinos in models of supersymmetry and Kaluza-Klein dark matter in universal extra dimensions.

4,614 citations

01 Jun 2005

3,154 citations

Journal ArticleDOI
TL;DR: The development of novel materials is a fundamental focal point of chemical research; and this interest is mandated by advancements in all areas of industry and technology.
Abstract: The development of novel materials is a fundamental focal point of chemical research; and this interest is mandated by advancements in all areas of industry and technology. A good example of the synergism between scientific discovery and technological development is the electronics industry, where discoveries of new semiconducting materials resulted in the evolution from vacuum tubes to diodes and transistors, and eventually to miniature chips. The progression of this technology led to the development * To whom correspondence should be addressed. B.L.C.: (504) 2801385 (phone); (504) 280-3185 (fax); bcushing@uno.edu (e-mail). C.J.O.: (504)280-6846(phone);(504)280-3185(fax);coconnor@uno.edu (e-mail). 3893 Chem. Rev. 2004, 104, 3893−3946

2,621 citations