There have been great advances in charm physics at the B-factories in recent years, including the observation of D0-D0bar mixing and the discovery of many new hidden-charm states, some of them presumably exotic in structure. This talk reviews some of the recent Belle results, with emphasis on the hidden-charm sector. Evidence for two new charged states is presented for the first time at this conference.
We report on precise measurements of charmed hadron lifetimes from the Belle II experiment and on the measurement of the angle $γ$ combining Belle and Belle II data. To measure charmed hadron lifetimes we use samples of electron-positron collisions collected from 2019 to 2021 near the $Υ(4S)$ resonance, corresponding to integrated luminosities of up to 207.2 ${\rm fb^{-1}}$. The results are the world's best determinations, indicating excellent early detector performance. We measure the angle $γ$ using a model-independent Dalitz plot analysis combining Belle and Belle II data, with a total samp…
We report on absolute lifetime measurements of charmed hadrons using the data collected by the Belle II experiment between 2019 and 2021. The measured lifetimes of $D^0$, $D^+$, and $Λ_c^+$ are the most precise to date and consistent with previous measurements. Our result indicates that $Ω_c^0$ is not the shortest-living singly charmed baryon.
Belle II实验正在日本KEK实验室进行。Belle II将研究处于或接近于Upperdum（4S）共振的e+e碰撞，目标是收集50 ab-1的数据，这比Belle和BaBar实验记录的数据有很大增加。这些数据将提供大量的粲介子衰变样本，Belle II将有一个非常活跃的粲物理程序。在这里，我们讨论了这个计划的一些亮点，重点是测量混合，CP破坏，轻子衰变。
Belle II is a major upgrade of the Belle experiment and will operate at the $B$-factory SuperKEKB in Japan. Here we discuss the expected sensitivity of Belle II for $D^0 - \bar{D}^0$ mixing and $CP$ violation measurements in the charm sector, which will benefit from a factor 50 increase in statistics and an improved vertex detection and particle identification. The impact on the determination of CKM parameters from the measurements of purely leptonic $D$ mesons decays is discussed. Finally a novel method of flavour tagging to substantially increase the sample of $D^0$ and $\bar{D}^0$ is presen…
Upgrades at the Belle II experiment and the SuperKEKB asymmetric-energy electron-positron collider enable precise measurements of particle decays. Even with early data, Belle II has made several world-leading measurements of particle lifetimes, which are useful as tests of effective models used in searches for physics beyond the standard model. Especially for charm hadrons, these effective models depend on careful consideration of non-perturbative effects to give an adequate description of lifetimes. Recent measurements at other experiments have stimulated particular interest in charm baryons,…
We present the selected recent charm results at Belle: (1) the $CP$ asymmetries and branching fractions for the decays of charm mesons, i.e. $D^{0}\toπ^{+}π^{-}η,\,K^{+}K^{-}η$ and $D^{0}\toϕη$; $D_{s}^{+}\to K^{+}π^{0},\,K^{+}η$ and $D_{s}^{+}\toπ^{+}π^{0},\,π^{+}η$. (2) the branching fractions for the decays of charmed baryons, i.e. $Λ_{c}^{+}\to pπ^{0},\,pη$; $Λ_{c}^{+}\toΛπ^{+}η,\,Σ^0π^{+}η$ and intermediate processes $Λ_{c}^{+}\toΛ(1670)π^{+},\,ηΣ(1385)^+$; $Ξ_c^0\toΛ\bar{K}^{*0},\,Σ^0\bar{K}^{*0}$ and $Σ^+K^{*-}$. (3) properties of excited charmed baryons, i.e. search for electromagnetic…
The large data sample accumulated by the Belle experiment at KEKB asymmetric energy $e^+ e^-$ collider provides opportunities to study charmonia (bottomonia) and charmonium-like (bottomonium-like) exotic particles. In this review, we report recent results on these topics from Belle, including searches for $B\to h_c K$, $B\to Y(4260)K$, $B\to X(3872/3915) (\to χ_{c1} π^0 ) K$, $B^0 \to X(3872) γ$, $e^+e^- \to γχ_{cJ}$ and a new measurement of the $e^+ e^-\to Υ(nS) π^+ π^- (n=1,2,3)$ cross sections at energies from 10.52 to 11.02 GeV.
Evidence from the \babar, Belle and CDF experiments for the phenomenon of \dzdzb\ oscillations is reviewed. A summary is made of the current understanding of the parameters defining the mixing of mass eigenstates that give rise to the oscillations. Results of searches for CP violation induced by mixing, are given, and estimates for the precision of measurements that can be expected in future experiments are made.
Measurements of Charmed Meson Lifetimes and Search for $D^0$-$\overline{D}^0$ Mixing with the Belle Experiment
用11.1 fb $^{-1} of data collected with the Belle detector at KEKB. Each candidate is fully reconstructed to identify the flavor of the charmed meson. The lifetimes are measured to be $ τ（D^0）=（414.5 \pm 1.7）$ fs, $ τ（D^+）=（1029 \pm 12）$ fs and $ τ（D^+）=（488.4^{+7.8}-7.7}）$ fs, where the error is statistical only. The mixing parameter $ y_{CP} $ is also measured to be $ y_{CP} =（1.16^{+1.67}-1.65}（stat.））%测量了粲介子的寿命$ through the lifetime difference of $ D^0$介子衰变到CP混合态和CP本征态。
Recent charm results from Belle experiment are presented in this proceedings, including (1) measurement of mixing parameter $y_{CP}=(0.96\pm0.91\pm 0.62^{+0.17}_{-0.00})\%$ in $CP$-odd decay for the first time, (2) the first Dalitz-plot analysis of $D^0\to K^-π^+η$, (3) measurement of branching fractions of $Λ_c^+\toηΛ^0π^+$ and $ηΣ^0π^+$ and intermediate processes $Λ_c^+\to[Λ(1670)\toηΛ^0]π^+$ and $Λ_c^+\toηΣ(1385)^+$ relative to $Λ_c^+\to p K^-π^+$: $0.293\pm0.003\pm0.014$, $0.120\pm0.006\pm0.006$, $(5.54\pm0.29\pm0.73)\times10^{-2}$, and $0.192\pm 0.006\pm 0.016$, respectively, and (4) firs…
We review measurements of semileptonic and leptonic charm meson decays performed by the Belle experiment, and we use these results to estimate the sensitivity of the follow-on Belle II experiment to these decays.
We present the measurements, performed by the Belle II experiment, related to the B and D meson decays. These results are based on 63 fb$^{-1}$ and 9 fb$^{-1}$ of $e^+e^-$ collision data recorded by the Belle II detector at a center-of-mass energy corresponding to the mass of the Y(4S) resonance and 60 MeV below the Y(4S) resonance. The results reassure that Belle II is in the right direction in pursuit of measuring the Standard Model predictions with improved precision.
$CP$ violation asymmetry is expected to be very small within the Standard Model. Observation of $CP$ violation in charm sector would hint towards New Physics. Time-reversal asymmetry is sensitive to $CPV$ via the $CPT$ Theorem, and is a clean and alternative way to search for CP violation in charm decays. This is achieved by the use of triple-product correlations in 4-body charm meson decays. The results from previous searches at BaBar and LHCb Collaborations and the latest results from Belle are reported. The most recent result from Belle performed in $D^{0} \to K^{+}K^{-}π^{+}π^{-}$ decays u…
