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B. R. Ko

Bio: B. R. Ko is an academic researcher from Korea University. The author has contributed to research in topics: Branching fraction & Meson. The author has an hindex of 21, co-authored 49 publications receiving 1262 citations.

Papers
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Journal ArticleDOI
X. L. Wang1, C. Z. Yuan, C. P. Shen2, P. Wang  +153 moreInstitutions (54)
TL;DR: In this article, the mass spectrum of pi(+)pi(-)psi(2S) with two coherent Breit-Wigner functions is fit with identical mass and width but different couplings to electron-positron pairs.
Abstract: We report measurement of the cross section of e(+)e(-) -> pi(+)pi(-)psi(2S) between 4.0 and 5.5 GeV, based on an analysis of initial state radiation events in a 980 fb(-1) data sample recorded with the Belle detector. The properties of the Y(4360) and Y(4660) states are determined. Fitting the mass spectrum of pi(+)pi(-)psi(2S) with two coherent Breit-Wigner functions, we find two solutions with identical mass and width but different couplings to electron-positron pairs: M-Y(4360) = (4347 +/- 6 +/- 3) MeV/c(2), Gamma(Y(4360)) = (103 +/- 9 +/- 5) MeV, M-Y(4660) = (4652 +/- 10 +/- 8) MeV/c(2), Gamma(Y(4660)) = (68 +/- 11 +/- 1) MeV; and B[Y(4360) -> pi(+)pi(-)psi(2S)] . Gamma(e+e-)(Y(4360)) = (10.9 +/- 0.6 +/- 0.7) eV and B[Y(4660) -> pi(+)pi(-)psi(2S)] . Gamma(e+e-)(Y(4660)) = (8.1 +/- 1.1 +/- 0.5) eV for one solution; or B[Y(4360) -> pi(+)pi(-)psi(2S)] . Gamma(e+e-)(Y(4360)) = (9.2 +/- 0.6 +/- 0.6) eV and B[Y(4660) -> pi(+)pi(-)psi(2S)] . Gamma(e+e-)(Y(4660)) = (2.0 +/- 0.3 +/- 0.2) eV for the other. Here, the first errors are statistical and the second systematic. Evidence for a charged charmoniumlike structure at 4.05 GeV/c(2) is observed in the pi(+/-)psi(2S) intermediate state in the Y(4360) decays.

112 citations

Journal ArticleDOI
TL;DR: Using data from the FOCUS experiment, the D+π− and D0π+ invariant mass distributions are analyzed to find evidence for broad structures over background in both the neutral and charged final state.

110 citations

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J. M. Link1, Marco A. Reyes1, P. M. Yager1, J. C. Anjos, I. Bediaga, C. Göbel, J. Magnin, A. Massafferri, J. M. De Miranda, Iuri Muniz Pepe, A. C. dos Reis, S. Carrillo2, E. Casimiro2, E. Cuautle2, A. Sanchez-Hernandez2, C. Uribe2, F. Vázquez2, L. Agostino3, L. Cinquini3, John Perry Cumalat3, B. O'Reilly3, J. E. Ramirez3, I. Segoni3, Michael Wahl3, J. N. Butler4, Harry Cheung4, G. Chiodini4, I. Gaines4, P. H. Garbincius4, L. A. Garren4, Erik Gottschalk4, P. H. Kasper4, A. E. Kreymer4, R. Kutschke4, Luigi Benussi, Stefano Bianco, F. L. Fabbri, A. Zallo, C. Cawlfield5, D. Y. Kim5, K. S. Park5, A. Rahimi5, J. Wiss5, Robert Gardner6, A. Kryemadhi6, K. H. Chang7, Y. S. Chung7, J. S. Kang7, B. R. Ko7, J. W. Kwak7, K. B. Lee7, Kyung-Suk Cho8, H. K. Park8, Gianluca Alimonti9, S. Barberis9, M. Boschini9, A. Cerutti9, P. D'Angelo9, M. DiCorato9, Paolo Dini9, L. Edera9, S. Erba9, Marco Giammarchi9, P. Inzani9, F. Leveraro9, Sandra Malvezzi9, Dario Menasce9, M. Mezzadri9, Luigi Moroni9, Daniele Pedrini9, C. Pontoglio9, F. Prelz9, Marco Rovere9, S. Sala9, T. F. Davenport10, V. Arena, G. Boca, Germano Bonomi, Gabriele Gianini, G. Liguori, M. M. Merlo, D. Pantea, David Lopes Pegna, S. P. Ratti, Cristina Riccardi, Paolo Vitulo, H. Hernandez11, A. M. Lopez11, E. Luiggi11, H. Mendez11, A. Paris11, J. Quinones11, W. Xiong11, Y. Zhang11, James R. Wilson12, T. Handler13, R. Mitchell13, D. Engh14, M. Hosack14, W. E. Johns14, M. S. Nehring14, Paul Sheldon14, Kevin Stenson14, Eric Wayne Vaandering14, Michael S. Webster14, M. Sheaff15 
TL;DR: In this article, a search for CPT violation in neutral charm meson oscillations was performed and the 95% confidence level limit is −0.0068 ξ ) y −(Im ξ) x N ( x, y, δ )(Δ a 0 + 0.6Δa Z ) −16 ǫ −16 Á −16 n −16 −16

80 citations

Journal ArticleDOI
B. Kronenbitter1, M. Heck1, P. Goldenzweig1, T. Kuhr2  +197 moreInstitutions (59)
TL;DR: In this paper, a measurement of the branching fraction of B+ -> tau(+) nu(tau) decays using a data sample of 772 x 10(6) B (B) over bar pairs, collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider.
Abstract: We report a measurement of the branching fraction of B+ -> tau(+) nu(tau) decays using a data sample of 772 x 10(6) B (B) over bar pairs, collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We reconstruct the accompanying B meson in a semileptonic decay and detect the recoiling B candidate in the decay channel B+ -> tau(+) nu(tau). We obtain a branching fraction of B(B+ -> tau(+) nu(tau)) = [1.25 +/- 0.28(stat.) +/- 0.27(syst.)] x 10-(4). This result is in good agreement with previous measurements and the expectation from the calculation based on the Standard Model.

64 citations

Journal ArticleDOI
TL;DR: In this paper, the K-matrix formalism is applied to the Dalitz plot analysis of D + s and D + to π + π − π+ for the first time, and the results are discussed along with their possible implications for the controversial σ meson.

64 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the authors report world averages of measurements of b-hadron, c-, c-, and tau-lepton properties obtained by the Heavy Flavor Averaging Group (HFAG) using results available through the end of 2011.
Abstract: This article reports world averages of measurements of b-hadron, c-hadron, and tau-lepton properties obtained by the Heavy Flavor Averaging Group (HFAG) using results available through the end of 2011. In some cases results available in the early part of 2012 are included. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, CP violation parameters, parameters of semileptonic decays and CKM matrix elements.

2,151 citations

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TL;DR: Recently, the LHCb Collaboration discovered two hidden-charm pentaquark states, which are also beyond the quark model as discussed by the authors, and investigated various theoretical interpretations of these candidates of the multiquark states.

1,083 citations

Journal ArticleDOI
TL;DR: In this article, the role of the gravitational sector in the Lorentz and CPT-violating standard-model extension (SME) is studied, and the leading-order terms in the SME action involving operators of mass dimension three and four are constructed.
Abstract: The role of the gravitational sector in the Lorentz- and CPT-violating standard-model extension (SME) is studied. A framework is developed for addressing this topic in the context of Riemann-Cartan spacetimes, which include as limiting cases the usual Riemann and Minkowski geometries. The methodology is first illustrated in the context of the QED extension in a Riemann-Cartan background. The full SME in this background is then considered, and the leading-order terms in the SME action involving operators of mass dimension three and four are constructed. The incorporation of arbitrary Lorentz and CPT violation into general relativity and other theories of gravity based on Riemann-Cartan geometries is discussed. The dominant terms in the effective low-energy action for the gravitational sector are provided, thereby completing the formulation of the leading-order terms in the SME with gravity. Explicit Lorentz symmetry breaking is found to be incompatible with generic Riemann-Cartan geometries, but spontaneous Lorentz breaking evades this difficulty.

1,082 citations

Journal ArticleDOI
TL;DR: In this article, the authors review experimental evidences of various candidates of hadronic molecules, and methods of identifying such structures Nonrelativistic effective field theories are the suitable framework for studying hadronic molecule, and are discussed in both the continuum and finite volumes.
Abstract: A large number of experimental discoveries especially in the heavy quarkonium sector that did not at all fit to the expectations of the until then very successful quark model led to a renaissance of hadron spectroscopy Among various explanations of the internal structure of these excitations, hadronic molecules, being analogues of light nuclei, play a unique role since for those predictions can be made with controlled uncertainty We review experimental evidences of various candidates of hadronic molecules, and methods of identifying such structures Nonrelativistic effective field theories are the suitable framework for studying hadronic molecules, and are discussed in both the continuum and finite volumes Also pertinent lattice QCD results are presented Further, we discuss the production mechanisms and decays of hadronic molecules, and comment on the reliability of certain assertions often made in the literature

1,016 citations

Journal ArticleDOI
TL;DR: The determination of the light-quark masses, the form factor, and the decay-constant ratio arising in semileptonic $$K \rightarrow \pi $$K→π transition at zero momentum transfer are reported on.
Abstract: We review lattice results related to pion, kaon, D- and B-meson physics with the aim of making them easily accessible to the particle physics community. More specifically, we report on the determination of the light-quark masses, the form factor f+(0), arising in semileptonic K -> pi transition at zero momentum transfer, as well as the decay constant ratio fK/fpi of decay constants and its consequences for the CKM matrix elements Vus and Vud. Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of SU(2)LxSU(2)R and SU(3)LxSU(3)R Chiral Perturbation Theory and review the determination of the BK parameter of neutral kaon mixing. The inclusion of heavy-quark quantities significantly expands the FLAG scope with respect to the previous review. Therefore, for this review, we focus on D- and B-meson decay constants, form factors, and mixing parameters, since these are most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. In addition we review the status of lattice determinations of the strong coupling constant alpha_s.

901 citations