We present measurements of branching fractions for five B-meson decays to two-body charmless final states. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 459 million BBbar pairs. The results for branching fractions are, in units of 10^{-6} (upper limits at 90% C.L.): BR(B+ -> etarho+) = 9.9 +/- 1.2 +/- 0.8, BR(B0 -> eta'eta) = 0.5 +/- 0.4 +/- 0.1 (<1.2), BR(B0 -> etapi0) = 0.9 +/- 0.4 +/- 0.1 (<1.5), BR(B0 -> eta'pi0) = 0.9 +/- 0.4 +/- 0.1 (<1.5), and BR(B0 -> omegapi0) = 0.07 +/- 0.26 +/- 0.02 (<0.5). The first error quoted is statistical and the second systematic. For the etarho+ mode, we measure the charge asymmetry Ach(B+ -> etarho+) = 0.13 +/- 0.11 +/- 0.02.
Measurement of branching fractions and charge asymmetries in B+ decays to etapi+, etaK+, etarho+ and eta'pi+, and search for B0 decays to etaK0 and etaomega
我们提出了测量的分支分数和电荷不对称性的六个B介子衰变模式与eta或eta'介子在最终状态。数据样本对应于SLAC的PEP-II非对称能量e+ e-B工厂的BABAR探测器收集的2.32亿个BBbar对。我们测量了分支分数（单位为10^-6）：B（B->etapi+）=5.1+/-0.6+/-0.3，B（B->etaK+）=3.3+/-0.6+/-0.3，B（B-> etaK 0）=1.5+/-0.7+/-0.1（在90% C. L.时<2.5），B（B-> η ω +）=8.4+/-1.9+/-1.1，B（B-> η ω）=1.0+/-0.5+/-0.2（在90% C.L.时<1.9），以及B（B-> η π +）=4.0+/-0.8+/-0.4，其中第一不确定度是统计的，第二不确定度是系统的。我们还确定了带电模式的电荷不对称性：Ach（B->etapi+）=-0.13+/-0.12+/-0.01，Ach（B->etaK+）=-0.20+/-0.15+/-0.01，Ach（B->etarho+）=0.02+/-0.18+/-0.02，Ach（B-> etaK+）=0.14+/-0.16+/-0.01。
B Meson Decays to eta(')K*, eta(')rho,eta(')pi0, omegapi0, and phipi0
We present measurements of the branching fractions and charge asymmetries (where appropriate) of two-body B decays to eta(')K*, eta(')rho, eta(')pi0, omegapi0, and phipi0. The data were recorded with the BABAR detector at PEP-II and correspond to 89x10^6 BB pairs produced in e+e- annihilation through the Upsilon(4S) resonance. We find significant signals for two decay modes and measure the branching fractions BR(B+->etaK*+)=(25.6+/-4.0+/-2.4)x10^{-6} and BR(B0->etaK*0)=(18.6+/-2.3+/-1.2)x10^{-6}, where the first error is statistical and the second systematic. We also find evidence with signifi…
Search for Nucleon Decay with Final States l+ eta, nubar eta, and nubar pi+,0 Using Soudan 2
我们用Soudan 2型铁跟踪量能器4.4千吨年的基准曝光量研究了核子衰变成5个两体末态的过程。对于质子衰变到完全可见的最终状态mu+ eta和e+ eta，我们观察到零和一个事件，分别满足我们的搜索标准的核子衰变。因此，在90%置信水平下，寿命下限（tau/B）为89 x 10^30年和81 x 10^30年。对于中子衰变到nubar η，我们得到寿命下限为71 × 10^30年。还报告了中子衰变成nubar pi 0和质子衰变成nubar pi+的极限。
A Search for the Rare Decays B --> pi l+l- and B0 --> eta l+l-
我们使用一个由BABAR探测器收集的对应于428 fb^-1的积分亮度的e+e--> Y（4S）BB衰变样本，给出了对罕见的变味中性流衰变B --> pi l+l-（pi=pi+/-，pi 0和l = e，mu）和B 0--> eta l+l-的搜索结果。没有观察到明显的信号，我们将同位旋和轻子味平均分支分数的上限设为BF（B --> pi l+l-）< 7.0 x 10^-8，轻子味平均分支分数的上限设为BF（B 0--> eta l+l-）< 9.2 x 10^-8，两者都是在90%的置信水平下。我们还报告了各个模式B+ --> pi+ e+e-、B 0--> pi 0 e+e-、B+ --> pi+ mu+mu-、B 0--> pi 0 mu+ mu-、B 0--> eta e+e-和B 0--> eta mu+mu-的90%置信水平分支分数上限。
Using CLEO-c data, we confirm the observation of D0 ->omega eta by BESIII. In the Dalitz Plot of D0 -> Kshort eta pi0, we find a background in the Kshort(->pipi)pi0 projection with a m(pipipi0) equal to the omega(782) mass. In a direct search for D0 -> (omega eta) we find a clear signal and measure BF(D0 ->omega eta) = (1.78+/-0.19+/-0.14) x 10**(-3), in good agreement with BESIII.
Measurement of the exclusive branching fractions B^0 --> eta K^{*0) and B^+ --> eta K^{*+}
我们根据1999年和2000年在PEP-II用BABAR探测器收集的20.7 fb-1的数据，给出了B衰变到两个无粲二体末态B^0 --> eta K^{*0}和B^+ --> eta K^{*+}的搜索结果。我们发现分支分数BF（B^0 --> eta K^{*0}）=（19.8^{+6.5}_{-5.6} +/- 1.7）x 10^{-6}和BF（B^+ --> eta K^{*+}）=（22.1^{+11.1}_{-9.2} +/- 3.3）x 10^{-6}，其中引用的第一个误差是统计误差，第二个误差是系统误差。
Improved Measurements of Branching Fractions and CP Asymmetries in B-> eta h Decays
We report improved measurements of B decays with an eta meson in the final state using 492 fb^{-1} of data collected by the Belle detector at the KEKB e^+ e^- collider. We observe the decays B^{+-}-> eta pi^{+-} and B^{+-}-> eta K^{+-}; the measured branching fractions are Br(B^{+-}-> eta pi^{+-}) = (4.2+- 0.4(stat)+- 0.2(sys))x10^{-6} and Br(B^{+-}-> eta K^{+-}) = (1.9+-0.3(stat)^{+0.2}_{-0.1}(sys))x10^{-6}. The corresponding CP-violating asymmetries are measured to be -0.23+- 0.09(stat) +-0.02(sys) for eta pi^{+-} and -0.39+-0.16(stat)+-0.03(sys) for eta K^{+-}. We also search for B^0-> eta …
Study of psi(2S) Decays to gamma p bar{p}, pi^0 p bar{p} and eta p bar{p} and Search for p bar{p} Threshold Enhancements
The decays of psi(2S) into gamma p bar{p}, pi^0 p bar{p} and eta p bar{p} have been studied with the CLEO-c detector using a sample of 24.5 million psi(2S) events obtained from e^+e^- annihilations at sqrt{s} = 3686 MeV. The data show evidence for the excitation of several N^* resonances in p pi^0 and p eta channels in pi^0 p bar{p} and eta p bar{p} decays, and f_2 states in gamma p bar{p} decay. Branching fractions for decays of psi(2S) to gamma p bar{p}, pi^0 p bar{p} and eta p bar{p} have been determined. No evidence for p bar{p} threshold enhancements was found in the reactions psi(2S)-> X…
In May-June 2014, the experiment devoted to the search for the bound state of the $η$ meson and $^3$$He$ nucleus has been performed at COSY accelerator in Research Center Jülich in Germany with WASA-at-COSY facility. The excitation functions for $pd\rightarrow^3$$He2γ$, $pd\rightarrow^3$$He6γ$, $pd\rightarrow pppπ^{-}$, $pd\rightarrow ppnπ^{0}$, $pd\rightarrow dnπ^{-}$, $pd\rightarrow dpπ^{0}$, $pd\rightarrow pd$, and $pd\rightarrow ppn$ reactions have been measured in the vicinity of the $η$ meson production threshold. The experiment was carried out using COSY ramped proton beam and deuterium…
