We report on the first Belle II measurements of branching fractions and CP-violating charge asymmetries in charmless $B$ decays. We use 34.6 fb$^{-1}$ from electron-positron collisions collected in 2019 and 2020 at the $Υ(4S)$ resonance. The results are compatible with known values and show performance already comparable with Belle.
Charmless hadronic $B$ decays are a good testing ground for the Standard Model (SM) of Particle Physics. The dominant amplitudes are CKM suppressed tree diagrams and/or $ b\to s$ or $b\to d$ loop ("penguin") diagrams. Non-SM particle could appear in the loop, and hence these decays are sensitive to search for New Physics (NP). Some of the recent measurements of two-body charmless hadronic $B$ decays from Belle and their prospects at Belle II are discussed.
Two-body charmless hadronic decays of $B$ mesons are important for determining Standard Model parameters and for detecting the presence of new physics. We present recent results from the Belle experiment on the charmless hadronic decays $B\rightarrow ηπ^0$ and $B\rightarrow π^0 π^0$.
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.
We report on recent results on charmless hadronic and radiative rare $B_s^0$ decays, based on the data collected by the Belle experiment at the KEKB $e^+e^-$ collider. These include the studies of $B_s^0\rightarrow K^0\bar{K^0}$, $B_s^0\rightarrowϕγ$ and $B_s^0\rightarrowγγ$.
We report on the first measurements of branching fractions, CP-violating charge asymmetries, and longitudinal polarization fractions in charmless $B$ decays at the Belle II experiment. We use a sample of electron-positron collisions collected in 2019 and 2020 at the $Υ(4S)$ resonance that corresponds to 34.6 fb$^{-1}$ of integrated luminosity. The results are compatible with the known values, which indicates a good understanding of detector performance.
Hadronic $B$ decays without a charm quark constitute a powerful probe to search for physics beyond the standard model as well as to provide constraints on $CP$ violation parameters. We report final measurements from Belle of the branching fractions and $CP$ asymmetries for the decays $B^{0} \rightarrow π^{0} π^{0}$ and $B^{\pm} \rightarrow K^{+} K^{-} π^{\pm}$. The $B^{0} \rightarrow π^{0} π^{0}$ measurements enable us to improve constraints on the angle $ϕ_{2}$ of the CKM unitarity triangle. For $B^{\pm} \rightarrow K^{+} K^{-} π^{\pm}$ we measure $CP$ asymmetry as a function of the invariant…
Study of charmless B decays to three-kaon final states
本文报道了无粲B介子衰变到三K介子末态的研究。实验结果是在KEKB非对称能量$e^+e^-$对撞机上用Belle探测器在Y(4S)共振上采集的78.7 1/fb数据样本得到的。给出了B衰变到三体K+K+K-、K 0 K +K-、KsKsK+和KsKsKs终态的分支分数。我们还首次尝试对三K介子末态进行了同位旋分析。
We report on the measurement of inclusive charmless semileptonic B decays $B \to X_{u} \ell ν$. The analysis makes use of hadronic tagging and is performed on the full data set of the Belle experiment comprising 772 million $B\bar{B}$ pairs. In the proceedings, the preliminary results of measurements of partial branching fractions and the CKM matrix element $|V_{ub}|$ are presented.
Recently Belle collaboration reported new measurements for the branching fractions with the first observing two processes of $\mathcal{B}(Ξ_c^0\toΛK^0_S)$, $\mathcal{B}(Ξ_c^0\toΣ^0 K^0_S)$ and updating data for $\mathcal{B}(Ξ_c^0\toΣ^+ K^-)$. Combined with other known data on charmless two body decays of anti-triplet charmed baryons, a lot of information can be derived with the assistance of $SU(3)$ flavour symmetry. Using $SU(3)$ relations between different decay modes, we can give some predictions based on the new measurements which can be tested with the high luminosity experiments in the f…
The study of charmless b-hadron decays provides information for testing the CKM picture of CP violation in the Standard Model. In addition, as they can proceed through loop diagrams, they are also sensitive to physics beyond the Standard Model. A review of recent results from LHCb on charmless b-hadron decays is presented.
Charmless $B$ decays are dominated by contributions from the short distance amplitudes from tree level and penguin loop-level amplitudes. The Tree contribution presents a weak phase $γ$. The relationship between these two amplitudes can generated a CP asymmetry depending from the relative amount among them in a particular decay. In multi-body charmless $B$ decays, these relative contribution can change along the phase space, given a non isotropic distribution of CP asymmetries in the Dalitz plot. Two recent LHCb analyses involving charmless multi-body B decays are discussed: the obsevation of …
Measurements of the CKM angle beta in charmless loop-dominated B meson decays at BaBar
本文报道了无粲中性B介子衰变到K+ K-K 0(包括共振衰变phiK 0和f0 K 0),eta'K 0,pi 0 K 0 s,K 0 sK 0 sK 0 s,K 0 sK 0 s,rho 0 K 0 s,omegaK 0 s的含时CP破坏不对称性的初步测量结果。这些结果是从SLAC PEP-2非对称能量B介子工厂的BaBar探测器收集的Y(4S)共振下e+e湮灭产生的高达3.47亿个BBbar对的数据样本中获得的。
Study of B meson decays to three-body charmless hadronic final states
本文报道无粲B介子衰变到三体KPiPi、KKPi和KKK末态的研究结果。测量了B衰变到K+0 Pi +Pi-,K+K+K-,K 0 K +K-,KsKsK+和KsKsKs终态的分支分数。首次观察到衰变B_0 => K_0 K +K ~-,B ~+=>KsKsK ~+和B_0 =>KsKsKs。我们还报道了B+=>K+K-Pi+衰变的证据。对于三体最终状态K 0 K +K-、KsKsPi+、K+K+Pi-和K-Pi+Pi+,报告了90%置信水平上限。最后讨论了用三体B 0 =>KsK+K衰变研究CP破坏的可能性。这些结果是由KEKB非对称能量e+e对撞机上的Belle探测器在Y(4S)共振下采集的78 fb^-1数据样本得到的。
Search for $B^0 \to p \bar{p}$, $Λ\barΛ$ and $B^+ \to p \barΛ$ at Belle
本文报道了基于140 fb^{-1}数据样本分析的无粲二体重子衰变B^0 \to p \bar{p},B^0 \to \bar和B^+ \to p \bar的搜寻结果。我们对它们的分支分数设置了90%置信水平上限:B(B^0 \to p \bar{p})< 4.1 x 10^{-7},B(B^0 \to <$\bar <$)< 6.9 x 10^{-7}$,B(B^+ \to p \bar <$)< 4.9 x 10^{-7}。