4 pages, 2 figures. To appear in the proceedings of the "XXIst International Europhysics Conference on High Energy Physics", 21-27 July 2011, Grenoble, France
The large data sample recorded with the Belle detector at the Y(5S) energy provides a unique opportunity to study the poorly-known $\bs$ meson. Two analyses, performed with a data sample representing an integrated luminosity of 121 /fb, are presented: the measurement of the Bs0->J/psi f0(980) and Bs0->J/psi f0(1370) branching fractions, and the 5sigma observation of the decay Bs0-bar->Lambda(c)+ pi- Lambda-bar which is the first observation of a baryonic Bs0 decay. In addition, we present new results of a measurement of the CKM angle phi_1(beta) with B pi tagged events.
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…
The Belle II experiment at the SuperKEKB accelerator is a next-generation B-factory aiming to collect 50 ab$^{-1}$, about 50 times the data collected at Belle, to study rare processes and make precision measurements that may expose physics beyond the Standard Model. Corresponding to roughly 100 PB of storage for raw data, plus dozens of PBs per year for Monte Carlo (MC) and analysis data, these massive samples require careful planning for the storage, processing, and analysis of data. This white paper notes some of the challenges that await grid-based user-analysis at the intensity frontier an…
Belle II has a broad $τ$ physics program, in particular in searches for lepton flavour and lepton number violations. Belle II profits from the relatively large $τ$-pair production rate in the low background environment of $e^+e^-$ -collisions at 10.58 GeV. Up to mid-2021 Belle II collected a sample corresponding to $214~\text{fb}^{-1}$ of data. We present a first measurement of the $τ$ mass, the prospects for the $τ$-lifetime measurement, and review the overall $τ$ lepton physics program of Belle II.
We report on preliminary measurements of branching fractions, charge-parity-violating asymmetries, and longitudinal polarization fractions in charmless bottom-meson decays from the Belle~II experiment. We use samples of electron-positron collisions collected in 2019 and 2020 at the $Υ(4S)$ resonance, corresponding to integrated luminosities of up to 62.8 ${\rm fb^{-1}}$. The results are compatible with known values, indicating good understanding of early detector performance.
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。
Study of Transitions and Decays of Bottomonia at Belle
本文综述了从Belle探测器在不同厄普塞隆共振态记录的e+ e-数据中对bottomonium态跃迁和衰变的研究。我们还报道了最近在Y（2S）数据样本中对χ_{bJ}（1 P）到41个强子末态的分支分数的研究。在该研究中，首次对τ total <2.4MeV时χ b 0（1 P）的宽度设定了90%置信上限。
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.
We report results on the search for $B_s\toη^{\prime}η$ decay, and the searches for $B^0\to\textrm{invisible}$ and $B^0\to\textrm{invisible}+γ$ decays. The former result is based on a data sample of $121.4~\textrm{fb}^{-1}$ recorded at the $Υ(5S)$ resonance while the later results are obtained from a $711~\textrm{fb}^{-1}$ of data sample collected at $Υ(4S)$ resonance with the Belle detector at the KEKB $e^+e^-$ collider. We observe no significant signal for the decays and set upper limit on their branching fractions at 90\% confidence level of $\mathcal{B}(B_s\toη^{\prime}η)<7.1\times 10^{-5}…
