We search for new charmless decays of neutral $b$--hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb$^{-1}$ of integrated luminosity, we report the first observation of the \BsKpi decay, with a significance of $8.2σ$, and measure $\BR(\BsKpi) = (5.0 \pm 0.7\stat \pm 0.8\syst)\times 10^{-6}$. We also report the first observation of charmless $b$--baryon decays in the channels \Lbppi and \LbpK with significances of $6.0σ$ and $11.5σ$ respectively, and we measure $\BR(\Lbppi) = (3.5 \pm 0.6\stat \pm 0.9\syst)\times 10^{-6}$ and $\BR(\LbpK) = (5.6 \pm 0.8\stat \pm 1.5\syst)\times 10^{-6}$. No evidence is found for the decays \BdKK and \Bspipi, and we set an improved upper limit $\BR(\Bspipi) < 1.2\times 10^{-6}$ at the 90% confidence level. All quoted branching fractions are measured using $\BR(\BdKpi)$ as a reference.
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.
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.
We present preliminary results of several searches for rare charmless hadronic decays of the B meson using data collected by the BABAR detector at the Stanford Linear Accelerator Center's PEP-II storage ring. We search for the decays h^+h^-, h^+h^-h^+, h^+h^-pi^0, X^0h^+, and X^0 K_S^0, where h = pi or K, and X^0 = eta^prime or omega. In a sample of 8.8 million B-anti-B decays we measure the branching fractions: BF(B^0 --> pi^+pi^-) = (9.3^{+2.6}_{-2.3}^{+1.2}_{-1.4}) x 10^{-6}, BF(B^0 --> K^+pi^-) = (12.5^{+3.0}_{-2.6}^{+1.3}_{-1.7}) x 10^{-6}, BF(B^0 --> rho^-pi^+) = (49 +/- 13^{+6}_{-5}) x …
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。
Flavor SU(3) analysis of heavy meson ($B$ and $D$) hadronic charmless decays can be formulated in two different ways. One is to construct the SU(3) irreducible representation amplitude (IRA) by decomposing effective Hamiltonian according to the SU(3) transformation properties. The other is to use the topological diagrams (TDA). These two methods should give equivalent physical results in the SU(3) limit. Using $B \to PP$ decays as an example, we point out that previous analyses in the literature using these two methods do not match consistently in several ways, in particular a few SU(3) indepe…
Charmless 2- and 3-body B decays and the angle alpha (phi2)
我们提出了初步测量的分支分数和CP-不对称参数在两体和三体无粲强子B衰变。现有的数据样本包括2.27亿次Uppersons(4S)B衰变,这些衰变是由SLAC的PEP-II非对称能量e+e对撞机上的BABAR探测器收集的。我们建立了衰变B --> pi 0 pi 0和B 0--> K 0 K 0 bar的观测,并在B --> pi pi系统中用全SU(2)同位旋分析和B 0--> pi+ pi-pi 0含时Dalitz图分析来约束CKM角α。
企鹅转变在重口味领域寻找新物理学线索中发挥着关键作用。在过去的十年中,CDF一直在探索这一机会,对中性B介子到带电终态粒子的两体无粲衰变进行了丰富的研究。在简要介绍了强子碰撞环境下的这一物理现象之后,我报告了两个有趣的结果:B^0_s--> phi_phi衰变的第一次极化测量和B^0(_s)--> h^+ h '^-衰变分析的更新。
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…