K. Chirapatpimol
A5018425023- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Computational Physics and Python Applications
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- Particle Detector Development and Performance
- Black Holes and Theoretical Physics
- Atomic and Subatomic Physics Research
- Medical Imaging Techniques and Applications
- Nuclear physics research studies
- Superconducting Materials and Applications
- Particle Accelerators and Free-Electron Lasers
- Advanced NMR Techniques and Applications
- Quantum, superfluid, helium dynamics
- Radiation Detection and Scintillator Technologies
- Calibration and Measurement Techniques
- advanced mathematical theories
- Acoustic Wave Resonator Technologies
- International Science and Diplomacy
- Atomic and Molecular Physics
- Ferroelectric and Piezoelectric Materials
- Stochastic processes and statistical mechanics
- Quantum and Classical Electrodynamics
- Particle accelerators and beam dynamics
Chiang Mai University
2012-2022
University of Virginia
2011-2022
We search for the rare decay <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msup><a:mi>B</a:mi><a:mo>+</a:mo></a:msup><a:mo stretchy="false">→</a:mo><a:msup><a:mi>K</a:mi><a:mo>+</a:mo></a:msup><a:mi>ν</a:mi><a:mover accent="true"><a:mi>ν</a:mi><a:mo stretchy="false">¯</a:mo></a:mover></a:math> in a <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline"><f:mn>362</f:mn><f:mtext> </f:mtext><f:mtext>...
We report the first measurement of target single spin asymmetries in semi-inclusive $^3{He}(e,e'\pi^\pm)X$ reaction on a transversely polarized target. The experiment, conducted at Jefferson Lab using 5.9 GeV electron beam, covers range 0.14 $< x <$ 0.34 with 1.3 $<Q^2<$ 2.7 GeV$^2$. Collins and Sivers moments were extracted from azimuthal angular dependence measured asymmetries. $\pi^\pm$ for $^3$He are consistent zero, except $\pi^+$ moment $x=0.34$, which deviates zero by 2.3$\sigma$....
We report a new, high-precision measurement of the proton elastic form factor ratio μpGE/GM for four-momentum transfer squared Q2=0.3–0.7(GeV/c)2. The was performed at Jefferson Lab (JLab) in Hall A using recoil polarimetry. With total uncertainty approximately 1%, new data clearly show that deviation from unity observed previous polarization measurements high Q2 continues down to lowest value this measurement. updated global fit includes results yields an electric (magnetic) roughly 2%...
We studied simultaneously the 4He(e,e'p), 4He(e,e'pp), and 4He(e,e'pn) reactions at Q^2=2 [GeV/c]2 x_B>1, for a (e,e'p) missing-momentum range of 400 to 830 MeV/c. The knocked-out proton was detected in coincidence with or neutron recoiling almost back missing momentum, leaving residual A=2 system low excitation energy. These data were used identify two-nucleon short-range correlated pairs deduce their isospin structure as function momentum region where nucleon-nucleon force is expected...
We present a search for the direct production of light pseudoscalar decaying into two photons with Belle II detector at SuperKEKB collider. process e^{+}e^{-}→γa, a→γγ in mass range 0.2<m_{a}<9.7 GeV/c^{2} using data corresponding to an integrated luminosity (445±3) pb^{-1}. Light pseudoscalars interacting predominantly standard model gauge bosons (so-called axionlike particles or ALPs) are frequently postulated extensions model. find no evidence ALPs and set 95% confidence level upper...
A search for the flavor-changing neutral-current decay B^{+}→K^{+}νν[over ¯] is performed at Belle II experiment SuperKEKB asymmetric energy electron-positron collider. The data sample corresponds to an integrated luminosity of 63 fb^{-1} collected ϒ(4S) resonance and a 9 60 MeV below resonance. Because measurable signature involves only single charged kaon, novel measurement approach used that exploits not properties decay, but also inclusive other B meson in ϒ(4S)→BB[over event, suppress...
We study the processes e^{+}e^{-}→ωχ_{bJ}(1P) (J=0, 1, or 2) using samples at center-of-mass energies sqrt[s]=10.701, 10.745, and 10.805 GeV, corresponding to 1.6, 9.8, 4.7 fb^{-1} of integrated luminosity, respectively. These data were collected with Belle II detector during special operations SuperKEKB collider above ϒ(4S) resonance. report first observation ωχ_{bJ}(1P) signals sqrt[s]=10.745 GeV. By combining results sqrt[s]=10.867 we find energy dependencies Born cross sections for...
We present the first measurement of ratio branching fractions inclusive semileptonic B-meson decays, R(X_{e/μ})=B(B→Xeν)/B(B→Xμν), a precision test electron-muon universality, using data corresponding to 189 fb^{-1} from electron-positron collisions collected with Belle II detector. In events where partner B meson is fully reconstructed, we use fits lepton momentum spectra above 1.3 GeV/c obtain R(X_{e/μ})=1.007±0.009(stat)±0.019(syst), which most precise lepton-universality its kind and...
We search for lepton-flavor-violating τ^{-}→e^{-}α and τ^{-}→μ^{-}α decays, where α is an invisible spin-0 boson. The uses electron-positron collisions at 10.58 GeV center-of-mass energy with integrated luminosity of 62.8 fb^{-1}, produced by the SuperKEKB collider collected Belle II detector. excess in lepton-energy spectrum known τ^{-}→e^{-}ν[over ¯]_{e}ν_{τ} τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ} decays. report 95% confidence-level upper limits on branching-fraction ratio...
The $L_{\mu}-L_{\tau}$ extension of the standard model predicts existence a lepton-flavor-universality-violating $Z^{\prime}$ boson that couples only to heavier lepton families. We search for such $Z^\prime$ through its invisible decay in process $e^+ e^- \to \mu^+ \mu^- Z^{\prime}$. use sample electron-positron collisions at center-of-mass energy 10.58GeV collected by Belle II experiment 2019-2020, corresponding an integrated luminosity 79.7fb$^{-1}$. find no excess over expected...
Abstract A series of data samples was collected with the Belle II detector at SuperKEKB collider from March 2019 to June 2022. We determine integrated luminosities these using three distinct methodologies involving Bhabha ( ), digamma and dimuon ) events. The total luminosity obtained Bhabha, digamma, events is (426.88 ± 0.03 2.61) fb −1 , (429.28 2.62) (423.99 0.04 3.83) where first uncertainties are statistical second systematic. resulting combination methods (427.87 2.01) .
We report measurements of time-dependent <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mi>C</a:mi><a:mi>P</a:mi></a:mrow></a:math> asymmetries in <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:msup><c:mi>B</c:mi><c:mn>0</c:mn></c:msup><c:mo stretchy="false">→</c:mo><c:msubsup><c:mi>K</c:mi><c:mi>S</c:mi><c:mn>0</c:mn></c:msubsup><c:msup><c:mi>π</c:mi><c:mn>0</c:mn></c:msup><c:mi>γ</c:mi></c:math> decays based on a data sample...
We present a measurement of the branching fraction and time-dependent charge-parity (<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>) decay-rate asymmetries in <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:msup><c:mi>B</c:mi><c:mn>0</c:mn></c:msup><c:mo stretchy="false">→</c:mo><c:mrow><c:mi>J</c:mi><c:mo>/</c:mo><c:mi>ψ</c:mi></c:mrow><c:msup><c:mi>π</c:mi><c:mn>0</c:mn></c:msup></c:math> decays. The data...
We measure the time-integrated <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> asymmetry in <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:msup><c:mi>D</c:mi><c:mn>0</c:mn></c:msup><c:mo stretchy="false">→</c:mo><c:msubsup><c:mi>K</c:mi><c:mi>S</c:mi><c:mn>0</c:mn></c:msubsup><c:msubsup><c:mi>K</c:mi><c:mi>S</c:mi><c:mn>0</c:mn></c:msubsup></c:math> decays reconstructed <f:math...
We present a measurement of the branching fraction $B^+\to\tau^+\nu_\tau$ decays using $(387\pm6)\times 10^6$ $\Upsilon(4S)$ collected between 2019 and 2022 with Belle II detector at SuperKEKB $e^+e^-$ collider. reconstruct accompanying $B^-$ meson hadronic tagging method, while candidates are identified in recoil. find evidence for 3.0 standard deviations, including systematic uncertainties. The measured is $\mathcal{B}(B^+\to\tau^+\nu_\tau) = [1.24 \pm 0.41 (\text{stat.}) 0.19...
Using data samples of 102 million Upsilon(1S) events and 158 Upsilon(2S) collected by the Belle detector at KEKB asymmetric-energy e+e- collider, we search for [udsccbar] pentaquark states decaying to Jpsi Lambda. first observations Upsilon(1S, 2S) inclusive decays Lambda, find evidence P_ccbars(4459)0 state with a significance 3.3 standard deviations, including statistical systematic uncertainties. We measure mass width Pccbars(4459)0 be (4471.7 +- 4.8 0.6) MeV/c2 (21.9 13.1 2.7) MeV,...
We measure the branching fraction of decay <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msup><a:mrow><a:mi>B</a:mi></a:mrow><a:mrow><a:mn>0</a:mn></a:mrow></a:msup><a:mo stretchy="false">→</a:mo><a:mi>J</a:mi><a:mo>/</a:mo><a:mi>ψ</a:mi><a:mi>ω</a:mi></a:mrow></a:math> using data collected with Belle II detector at SuperKEKB collider. The contain <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"><d:mrow><d:mo...
A bstract Using data samples of 983.0 fb − 1 and 427.9 accumulated with the Belle II detectors operating at KEKB SuperKEKB asymmetric-energy e + colliders, singly Cabibbo-suppressed decays $$ {\Xi}_c^{+}\to p{K}_S^0 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>Ξ</mml:mi> <mml:mi>c</mml:mi> <mml:mo>+</mml:mo> </mml:msubsup> <mml:mo>→</mml:mo> <mml:mi>p</mml:mi> <mml:mi>K</mml:mi> <mml:mi>S</mml:mi> <mml:mn>0</mml:mn> </mml:math> , \Lambda {\pi}^{+}...
A bstract We perform the first search for CP violation in $$ {D}_{(s)}^{+}\to {K}_S^0{K}^{-}{\pi}^{+}{\pi}^{+} <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mfenced> <mml:mi>s</mml:mi> </mml:mfenced> <mml:mo>+</mml:mo> </mml:msubsup> <mml:mo>→</mml:mo> <mml:mi>K</mml:mi> <mml:mi>S</mml:mi> <mml:mn>0</mml:mn> <mml:msup> <mml:mo>−</mml:mo> </mml:msup> <mml:mi>π</mml:mi> </mml:math> decays. use a combined data set from Belle and II experiments,...
We report the first measurement of double-spin asymmetry A{LT} for charged pion electroproduction in semi-inclusive deep-inelastic electron scattering on a transversely polarized {3}He target. The kinematics focused valence quark region, 0.16<x<0.35 with 1.4<Q{2}<2.7 GeV{2}. corresponding neutron asymmetries were extracted from measured and proton over cross section ratios using effective polarization approximation. These new data probe transverse momentum dependent parton distribution...
We report the first measurement of target single-spin asymmetries (A$_N$) in inclusive hadron production reaction, $e~$+$~^3\text{He}^{\uparrow}\rightarrow h+X$, using a transversely polarized $^3$He target. The experiment was conducted at Jefferson Lab Hall A 5.9-GeV electron beam. Three types hadrons ($\pi^{\pm}$, $\text{K}^{\pm}$ and proton) were detected transverse momentum range 0.54 $<p_T<$ 0.74 GeV/c. $x_F$ for pions -0.29 $<x_F<$ -0.23 kaons -0.25 $<x_F<$-0.18. observed asymmetry...
We present measurements of the first to fourth moments lepton mass squared q2 B→Xcℓ¯νℓ decays for ℓ=e, μ and with Xc a hadronic system containing charm quark. These results use sample electron-positron collisions at Υ(4S) resonance corresponding 62.8 fb−1 integrated luminosity collected by Belle II 2 experiment in 2019 2020. To identify reconstruct q2, one B mesons from an Υ(4S)→B¯B decay is fully reconstructed mode using multivariate tagging algorithm. report raw central q2>1.5 GeV2/c4 up...
We present a measurement of the τ-lepton mass using sample about 175 million e+e−→τ+τ− events collected with Belle II detector at SuperKEKB e+e− collider center-of-mass energy 10.579 GeV. This corresponds to an integrated luminosity 190 fb−1. use kinematic edge τ pseudomass distribution in decay τ−→π−π+π−ντ and measure be 1777.09±0.08±0.11 MeV/c2, where first uncertainty is statistical second systematic. result most precise date.Received 31 May 2023Accepted 13 July...
We determine the Cabibbo-Kobayashi-Maskawa matrix-element magnitude |Vcb| using B¯0→D*+ℓ−ν¯ℓ decays reconstructed in 189 fb−1 of collision data collected by Belle II experiment, located at SuperKEKB e+e− collider. Partial decay rates are reported as functions recoil parameter w and three angles separately for electron muon final states. obtain Boyd-Grinstein-Lebed Caprini-Lellouch-Neubert parametrizations, find |Vcb|BGL=(40.57±0.31±0.95±0.58)×10−3 |Vcb|CLN=(40.13±0.27±0.93±0.58)×10−3 with...