S. K. Choi
A5028477044- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Atomic and Subatomic Physics Research
- Neutrino Physics Research
- Black Holes and Theoretical Physics
- Particle Detector Development and Performance
- Particle Accelerators and Free-Electron Lasers
- Nuclear physics research studies
- Medical Imaging Techniques and Applications
- Dark Matter and Cosmic Phenomena
- Atomic and Molecular Physics
- Computational Physics and Python Applications
- Radioactive Decay and Measurement Techniques
- Quantum, superfluid, helium dynamics
- Cosmology and Gravitation Theories
- Superconducting Materials and Applications
- Enzyme Structure and Function
- Advanced NMR Techniques and Applications
- Chemical Synthesis and Analysis
- Advancements in PLL and VCO Technologies
- Ethics and Social Impacts of AI
- Artificial Intelligence in Healthcare and Education
- Metabolomics and Mass Spectrometry Studies
- Advanced Condensed Matter Physics
Chung-Ang University
2023-2025
Institute of High Energy Physics
2024
Soochow University
2022-2023
Inner Mongolia University
2023
Seoul National University Bundang Hospital
2023
Henan University
2023
University of Groningen
2023
Sigma Theta Tau International
2022
Moss Landing Marine Laboratories
2022
Gyeongsang National University
2011-2020
The Belle detector at the KEKB electron-positron collider has collected almost 1 billion Y(4S) events in its decade of operation. Super-KEKB, an upgrade is under construction, to increase luminosity by two orders magnitude during a three-year shutdown, with ultimate goal 8E35 /cm^2 /s luminosity. To exploit increased luminosity, been proposed. A new international collaboration Belle-II, being formed. Technical Design Report presents physics motivation, basic methods accelerator upgrade, as...
The cross section for ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\psi}(2S)$ between threshold and $\sqrt{s}=5.5\text{ }\text{ }\mathrm{GeV}$ is measured using $673\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of data on off the $\ensuremath{\Upsilon}(4S)$ resonance collected with Belle detector at KEKB. Two resonant structures are observed in...
With the full data sample of $772 \times 10^6$ $B{\bar B}$ pairs recorded by Belle detector at KEKB electron-positron collider, decay $\bar{B} \rightarrow D^* \tau^- \bar{\nu}_\tau$ is studied with hadronic $\tau$ decays $\tau^- \pi^- \nu_\tau$ and \rho^- \nu_\tau$. The polarization $P_\tau(D^*)$ in two-body measured, as well ratio branching fractions $R(D^{*}) = \mathcal{B}(\bar {B} \bar{\nu}_\tau) / \mathcal{B}(\bar{B} \ell^- \bar{\nu}_\ell)$, where $\ell^-$ denotes an electron or a muon....
We report the observation of prompt J/psi via double cc; production from e+e- continuum. In this process one pair fragments into a meson while remaining either produces charmonium state or open charm. Both cases have been experimentally observed. find cross sections sigma[e+e- -->J/psieta(c)(gamma)]xB(eta(c)-->>or=4 charged)=(0.033(+0.007)(-0.006)+/-0.009) pb and sigma(e+e- -->J/psiD(*+)X)=(0.53(+0.19)(-0.15)+/-0.14) infer -->J/psicc;)/sigma(e+e- -->J/psiX)=0.59(+0.15)(-0.13)+/-0.12. These...
We report measurement of the cross section $e^+e^-\to \pi^+\pi^-\psi(2S)$ between 4.0 and $5.5 {\rm GeV}$, based on an analysis initial state radiation events in a $980 \rm fb^{-1}$ data sample recorded with Belle detector. The properties $Y(4360)$ $Y(4660)$ states are determined. Fitting mass spectrum $\pi^+\pi^-\psi(2S)$ two coherent Breit-Wigner functions, we find solutions identical width but different couplings to electron-positron pairs: $M_{Y(4360)} = (4347\pm 6\pm 3) MeV}/c^2$,...
We report a study of $B\to (J/\psi \gamma) K$ and (\psi' \gamma)K$ decay modes using $772\times 10^{6}$ $B\bar{B}$ events collected at the \Upsilon(4S)$ resonance with Belle detector KEKB energy-asymmetric $e^+ e^-$ collider. observe $X(3872) \to J/\psi \gamma$ first evidence for $\chi_{c2} in (X_{c\bar{c}}\gamma) decays, while search \psi' no significant signal is found. measure branching fractions, $\mathcal{B}(B^{\pm} X(3872) K^{\pm}) \mathcal{B}(X(3872) J/\psi\gamma)$ $=$...
Based on <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mo stretchy="false">(</a:mo><a:mn>10</a:mn><a:mn>087</a:mn><a:mo>±</a:mo><a:mn>44</a:mn><a:mo stretchy="false">)</a:mo><a:mo>×</a:mo><a:msup><a:mrow><a:mn>10</a:mn></a:mrow><a:mrow><a:mn>6</a:mn></a:mrow></a:msup><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi>J</a:mi><a:mo>/</a:mo><a:mi>ψ</a:mi></a:mrow></a:math> events collected with the BESIII detector, a partial wave analysis of decay <e:math...
Based on 4.4 fb−1 of e+e− annihilation data collected at the center-of-mass energies between 4.60 and 4.70 GeV with BESIII detector BEPCII collider, pure W-boson-exchange decay Λc+→Ξ0K+ is studied a full angular analysis. The corresponding asymmetry measured for first time to be αΞ0K+=0.01±0.16(stat)±0.03(syst). This result reflects noninterference effect S- P-wave amplitudes. phase shift amplitudes has two solutions, which are δp−δs=−1.55±0.25(stat)±0.05(syst) rad or...
We report the observation of an isotriplet excited charmed baryons, decaying into Lambda(+)(c)pi(-), Lambda(+)(c)pi(0), and Lambda(+)(c)pi(+). measure mass differences M(Lambda(+)(c)pi)-M(Lambda(+)(c)) widths to be 515.4(+3.2+2.1)(-3.1-6.0) MeV/c(2), 61(+18+22)(-13-13) MeV for neutral state; 505.4(+5.8+12.4)(-4.6-2.0) 62(+37+52)(-23-38) charged 514.5(+3.4+2.8)(-3.1-4.9) 75(+18+12)(-13-11) doubly state, where uncertainties are statistical systematic, respectively. These results obtained from...
We report measurements of the exclusive cross section for e+e−→D¯¯¯D, where D=D0 or D+, in center-of-mass energy range from D¯¯¯D threshold to 5 GeV with initial-state radiation. The analysis is based on a data sample collected Belle detector an integrated luminosity 673 fb−1.Received 18 October 2007DOI:https://doi.org/10.1103/PhysRevD.77.011103©2008 American Physical Society
The cross sections for ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\phi}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ and ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\phi}{f}_{0}(980)$ are measured from threshold to $\sqrt{s}=3.0\text{ }\text{ }\mathrm{GeV}$ using initial-state radiation. analysis is based on a data sample of $673\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected below the $\ensuremath{\Upsilon}(4S)$ resonance with Belle...
We report measurements of B→χ(c1)γK and χ(c2)γK decays using 772×10(6) BB[over ¯] events collected at the Υ(4S) resonance with Belle detector KEKB asymmetric-energy e(+)e(-) collider. Evidence a new in χ(c1)γ final state is found statistical significance 3.8σ. This has mass 3823.1±1.8(stat)±0.7(syst) MeV/c(2), value that consistent theoretical expectations for previously unseen 1(3)D(2) cc[over meson. find no other narrow set upper limits on branching fractions X(3872)→χ(c1)γ χ(c2)γ decays.
We report the first evidence for ${\ensuremath{\eta}}_{b}(2S)$ using ${h}_{b}(2P)\ensuremath{\rightarrow}{\ensuremath{\eta}}_{b}(2S)\ensuremath{\gamma}$ transition and observation of ${h}_{b}(1P)\ensuremath{\rightarrow}{\ensuremath{\eta}}_{b}(1S)\ensuremath{\gamma}$ ${h}_{b}(2P)\ensuremath{\rightarrow}{\ensuremath{\eta}}_{b}(1S)\ensuremath{\gamma}$ transitions. The mass width ${\ensuremath{\eta}}_{b}(1S)$ are measured to be...
Cross sections for the process ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}_{S}^{0}{K}_{S}^{0}J/\ensuremath{\psi}$ at center-of-mass energies from 4.128 to 4.950 GeV are measured using data samples with a total integrated luminosity of $21.2\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected by BESIII detector operating BEPCII storage ring. The $Y(4230)$ state is observed in energy dependence cross section first time statistical significance $26.0\ensuremath{\sigma}$. In...
Using initial-state radiation events from a total integrated luminosity of $11.957\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ ${e}^{+}{e}^{\ensuremath{-}}$ collision data collected at center-of-mass energies between 3.773 and 4.258 GeV with the BESIII detector BEPCII, cross section for process ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}\overline{\mathrm{\ensuremath{\Lambda}}}$ is measured in 16...
We report measurements of branching fractions $\tau$ lepton decays to final states with a $K^{0}_{S}$ meson using 669 fb$^{-1}$ data sample accumulated the Belle detector at KEKB asymmetric-energy $e^{+}e^{-}$ collider. The inclusive fraction is measured be $\mathcal{B}(\tau^{-} \to K^{0}_{S}\ X^{-} \nu_{\tau})=(9.15 \pm 0.01 0.15) \times 10^{-3}$, where $X^{-}$ can anything; exclusive are \pi^{-} K^{0}_{S} \nu_{\tau}) = (4.16 0.08) K^{-} (7.40 0.07 0.27) 10^{-4}$, \pi^{0} (1.93 0.02 0.07)...
Based on a data sample of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mo stretchy="false">(</a:mo><a:mn>2712.4</a:mn><a:mo>±</a:mo><a:mn>14.3</a:mn><a:mo stretchy="false">)</a:mo><a:mo>×</a:mo><a:msup><a:mn>10</a:mn><a:mn>6</a:mn></a:msup><a:mi>ψ</a:mi><a:mo stretchy="false">(</a:mo><a:mn>3686</a:mn><a:mo stretchy="false">)</a:mo></a:math> events collected with the BESIII detector at BEPCII collider, M1 transition <g:math...
We perform for the first time an amplitude analysis of decay D+→KS0π+η and report observation D+→KS0a0(980)+ using 2.93 fb−1 e+e− collision data taken at a center-of-mass energy 3.773 GeV with BESIII detector. As only W-annihilation-free among D to a0(980) pseudoscalar, is ideal in extracting contributions W-emission amplitudes involving study final-state interactions. The absolute branching fraction measured be (1.27±0.04stat±0.03syst)%. fractions intermediate processes a0(980)+→π+η...
We present the first observation of singly Cabibbo-suppressed decay <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msubsup><a:mi mathvariant="normal">Λ</a:mi><a:mi>c</a:mi><a:mo>+</a:mo></a:msubsup><a:mo stretchy="false">→</a:mo><a:mi mathvariant="normal">Λ</a:mi><a:msup><a:mi>K</a:mi><a:mo>+</a:mo></a:msup><a:msup><a:mi>π</a:mi><a:mn>0</a:mn></a:msup></a:math> with a significance <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"...
A search has been performed for the semileptonic decays D0→KS0K−e+νe, D+→KS0KS0e+νe, and D+→K+K−e+νe, using 7.9 fb−1 of e+e− annihilation data collected at center-of-mass energy s=3.773 GeV by BESIII detector operating BEPCII collider. No significant signals are observed, upper limits set 90% confidence level 2.13×10−5, 1.54×10−5, 2.10×10−5 branching fractions respectively.Received 14 December 2023Accepted 28 February 2024DOI:https://doi.org/10.1103/PhysRevD.109.072003Published American...
The <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>C</a:mi><a:mi>P</a:mi></a:math>-even fractions (<c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:msub><c:mi>F</c:mi><c:mo>+</c:mo></c:msub></c:math>) of the decays <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mrow><e:msup><e:mrow><e:mi>D</e:mi></e:mrow><e:mrow><e:mn>0</e:mn></e:mrow></e:msup><e:mo...
The inclusive cross sections of prompt <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mi>J</a:mi><a:mo>/</a:mo><a:mi>ψ</a:mi></a:mrow></a:math> and <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>ψ</c:mi><c:mo stretchy="false">(</c:mo><c:mn>3686</c:mn><c:mo stretchy="false">)</c:mo></c:math> production are measured at center-of-mass energies from 3.808 to 4.951 GeV. dataset used is <g:math...
A bstract Based on (2712 . 4 ± 14 3) × 10 6 ψ (3686) events collected at the BESIII detector operating BEPCII collider, we present first observation of decay $$ \psi (3686)\to {K}^{-}\Lambda (1520){\overline{\Xi}}^{+} <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>ψ</mml:mi> <mml:mfenced> <mml:mn>3686</mml:mn> </mml:mfenced> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>K</mml:mi> <mml:mo>−</mml:mo> </mml:msup> <mml:mi>Λ</mml:mi> <mml:mn>1520</mml:mn> <mml:mover>...
Using a sample of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mo>∼</a:mo><a:msup><a:mrow><a:mn>10</a:mn></a:mrow><a:mrow><a:mn>10</a:mn></a:mrow></a:msup><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi>J</a:mi><a:mo>/</a:mo><a:mi>ψ</a:mi></a:mrow></a:math> events collected by the BESIII detector at BEPCII collider, partial-wave analysis decay <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"...