Large transverse single-spin asymmetries, A_{N}, have been observed in forward hadron production at RHIC. STAR has reported precision measurements of the x_{F}-p_{T} dependence of A_{N} for forward pi^0 production. Contrary to expectation, the asymmetry does not fall with p_{T}. However, questions remain about the trend at the lower end of the studied range, p_{T}~1 GeV/c. Analysis of data from the 2008 RHIC run has extended the pi^0 data in the x_{F} > 0.4, low p_{T} region. Preliminary results are reported.
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。
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 …
Measurements of Branching Fractions and CP Asymmetries in B-> etah Decays
我们利用KEKB e^+ e^-对撞机Belle探测器收集的140 fb^{-1}的数据，测量了B到赝标-赝标衰变，其中至少有一个η介子处于末态。我们观察到B^+-> eta pi^+的衰变，并发现了B^+-> eta K+的证据;测得的分支分数为B（B^+-> eta pi^+）=（4.8^{+0.8}_{-0.7}（stat）+- 0.3（sys））*10^{-6}和B（B^+-> eta K^+）=（2.1 +- 0.6（stat）+- 0.2（sys））*10^{-6}。测得它们对应的CP破坏不对称性，对于eta pi^+-为0.07+- 0.15（stat）+- 0.03（sys），对于eta K^+-为-0.49+- 0.31（stat）+- 0.07（sys）。对于中性B->eta h衰变没有发现显著的信号。我们在90%置信水平下报告了以下分支分数的上限：B（B-> eta K^0 < 2.0* 10^{-6}，B（B-> eta pi 0）<2.5*10^{-6}和B（B-> eta eta）<2.0*10^{-6}。
Improved Measurements of Branching Fractions and CP Asymmetries in B-> eta h Decays
我们利用KEKB e ^+ e ^-对撞机上Belle探测器收集的357 fb ^-1数据，改进了对末态eta介子的B衰变的测量。我们观察到衰变B ^+--> η pi ^+-和B ^+--> η K ^+-;测得的分支分数为Br（B ^+--> η pi ^+-）=（3.9 +-0.5（stat.）+- 0.2（系统））* 10 ^-6和Br（B ^+-> eta K ^+-）=（2.2 +-0.4（stat.）+- 0.1（系统））* 10 ^-6，分别。它们相应的CP破坏不对称性测量为-0.10 +-0.11（stat.）+- 0.02（系统）对于eta pi ^+-和-0.55 +-0.19（统计）+ 0.04 - 0.03（系统）对于η K ^+-。没有发现B^0-> eta K^0衰变的显著信号;在90%置信水平下，分支分数的上限是Br（B^0-> eta K^0）<1.9 * 10 ^-6。
Observation of Time-Dependent CP Violation in B0 -> eta' K0 Decays and Improved Measurements of CP Asymmetries in B0 -> phiK0, KsKsKs and B0 -> J/psi K0 Decays
Transverse Single Spin Asymmetries and Cross-Sections for Forward pi0 and eta Mesons at Large Feynman-x in sqrt(s)=200 GeV polarized p+p Collisions at STAR
Measurements of charge and CP asymmetries in $b$-hadron decays using top-quark events collected by the ATLAS detector in $pp$ collisions at $\sqrt{s}=8$ TeV
Measurement of Transverse Single-Spin Asymmetries for Mid-rapidity Production of Neutral Pions and Charged Hadrons in Polarized p+p Collisions at sqrt(s) = 200 GeV
Experimental observations of strikingly large transverse single-spin asymmetries (TSSAs) opened a window into quark and gluon dynamics present in hadronic collisions, revealing large spin-momentum correlations within nucleons and in the process of forming hadrons. Though originally measured in lower energy fixed target experiments, they have been found to persist in collisions with momentum transfer well into the perturbative regime of quantum chromodynamics (QCD) and yet their origin remains poorly understood. TSSA measurements have allowed for the development of both transverse momentum depe…
Longitudinally polarized $p+p$ scattering experiments provide access to gluon polarization via measurement of the double helicity asymmetry, $A_{LL}$. At the completion of the 2013 RHIC running period, a significant dataset of $π^{0}$s corresponding to an integrated luminosity of 46 $\text{pb}^{-1}$ (2012) and 8 $\text{pb}^{-1}$ (2013) produced from polarized $p+p$ scattering at $\sqrt{s}=510$ GeV with an average beam polarization of approximately $50\%$ was acquired. The $π^{0}$ kinematics were measured via isolation cones by the STAR Forward Meson Spectrometer, an electromagnetic calorimeter…
Rapidity gap cross sections measured with the ATLAS detector in pp collisions at sqrt(s) = 7 TeV
利用积分亮度为7.1微仓的最小偏差数据样本，研究了sqrt（s）= 7 TeV质子-质子碰撞中赝快度能隙的分布。截面是用Δ eta F差分测量的，在eta = +/- 4.9时，扩展到ATLAS灵敏度极限的伪快度区域中较大的一个，其中在横向动量阈值p_T Cut以上没有产生终态粒子。对于200 < p_T切割< 800 MeV，测量跨越区域0 <Δ eta F < 8。在小Δ eta F，数据测试强子化模型的可靠性，在描述速度和横向动量波动的最终状态粒子生产。在更大的间隙尺寸的测量是由来自单衍射解离过程（pp -> Xp）的贡献占主导地位，由双解离（pp -> XY）增强，其中两个解离系统中较轻的不变质量满足M_Y <~ 7 GeV。得到的截面为d sigma / d Delta eta F ~ 1 mb，其中Delta eta F >~ 3。大快度间隙的数据被用来约束的软衍射的三重Regge模型适当的坡密子截距的值。集成在所有间隙尺寸的截面与其他LHC非弹性截面测量进行了比较。
Results are presented for the transverse single-spin asymmetries of direct photons, neutral pions, and eta mesons for $|η|<0.35$ from $p^\uparrow + p$ collisions with $\sqrt{s} = 200$ GeV at PHENIX. As hadrons, $π^0$ and $η$ mesons are sensitive to both initial- and final-state effects and at midrapidity probe the dynamics of gluons along with a mix of quark flavors. Because direct photon production does not include hadronization, the direct photon TSSA is only sensitive to initial-state effects and at midrapidity provides a clean probe of the gluon dynamics in transversely polarized protons. …
