Search for the decay phi -> K0 K0bar gamma with the KLOE experiment
KLOE Collaboration, F. Ambrosino, A. Antonelli, M. Antonelli, F. Archilli, P. Beltrame, G. Bencivenni, S. Bertolucci, C. Bini, C. Bloise, S. Bocchetta, F. Bossi… 展开作者
KLOE Collaboration, F. Ambrosino, A. Antonelli, M. Antonelli, F. Archilli, P. Beltrame, G. Bencivenni, S. Bertolucci, C. Bini, C. Bloise, S. Bocchetta, F. Bossi, P. Branchini, G. Capon, T. Capussela, F. Ceradini, P. Ciambrone, E. De Lucia, A. De Santis, P. De Simone, G. De Zorzi, A. Denig, A. Di Domenico, C. Di Donato, B. Di Micco, M. Dreucci, G. Felici, S. Fiore, P. Franzini, C. Gatti, P. Gauzzi, S. Giovannella, E. Graziani, G. Lanfranchi, J. Lee-Franzini, M. Martini, P. Massarotti, S. Meola, S. Miscetti, M. Moulson, S. Müller, F. Murtas, M. Napolitano, F. Nguyen, M. Palutan, E. Pasqualucci, A. Passeri, V. Patera, P. Santangelo, B. Sciascia, T. Spadaro, M. Testa, L. Tortora, P. Valente, G. Venanzoni, R. Versaci, G. Xu
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11 pages, 8 figures, submitted to Physics Letters B
我们在DAFNE的KLOE实验收集的大约1.5 × 10^9个φ衰变的样品中,通过探测K_s对加上一个光子,并使K_s介子衰变到π ^+ π ^-,来寻找φ-> K 0 K 0巴γ衰变。反应通过中间态f_0(980)γ、a_0(980)γ进行。我们发现5个事件与3.2事件预期从背景过程。我们得到了上限:在90% C. L时,BR(φ-> K 0 K 0巴-γ)<1.9 × 10 ^-8。.
英文摘要:
We have searched for the decay phi -> K0 K0bar gamma, by detecting K_s pairs plus a photon and with the K_s-mesons decaying to pi^+ pi^-, in a sample of about 1.5x 10^9 phi-decays collected by the KLOE experiment at DAFNE. The reaction proceeds through the intermediate states f_0(980) gamma, a_0(980) gamma. We find five events with 3.2 events expected from background processes. We obtain the upper limit: BR (phi -> K0 K0bar gamma) < 1.9x10^-8 at 90% C.L. .
Study of the Decay phi --> pi0 pi0 gamma with the KLOE Detector
我们已经用KLOE探测器测量了分支比BR(phi --> pi 0 pi 0 gamma),使用的是~ 5 × 10^7 phi衰变的样品。phi介子是在DAFNE,弗拉斯卡蒂phi工厂生产的。我们发现BR(phi --> pi 0 pi 0 gamma)=(1.09 +- 0.03(stat)+- 0.05(syst))x10^-4。我们适合的两π介子质谱模型解开各种来源的贡献。
Dalitz plot analysis of e+ e- --> pi0 pi0 gamma events at SQRT(s) ~ M(phi) with the KLOE detector
本文研究了用KLOE探测器在SQRT(s)~ M(phi)上采集的e+ e-> pi 0 pi 0 γ事例的Dalitz图。在双介子不变质量(Mpp)低于700 MeV的区域中,所研究的过程由非共振过程e+ e-> omega -> pi 0和omega --> pi 0 γ主导,而对于更高的Mpp值,辐射phi衰变到f0(980)是主导机制。使用不同的理论模型来拟合Dalitz图,同时考虑到sigma(600)的可能贡献。对于每个模型,我们提取f0(980)质量及其与pipi,KKbar和phi的耦合。
Precise measurement of Gamma(Ks->pi+pi-(gamma))/Gamma(Ks->pi0pi0) with the KLOE detector at DAFNE
利用2001年和2002年在DAFNE e+e对撞机上产生的4亿多个phi->KsKl衰变样品,用KLOE探测器测量了R=Gamma(Ks->pi+pi-(g))/Gamma(Ks-> pi 0 pi 0)。结果是R=2.2555+-0.0012(stat)+-0.0021(syst-stat)+-0.0050(systt),这与先前发表的基于2000年KLOE数据样本的结果非常一致。KLOE结果的平均值为R=2.2549+-0.0054,将总误差减少了三倍,达到0.25%。
A Study of the Radiative Ke3 Decay and Search for Direct Photon Emission with the KLOE Detector
我们给出了对应于大约350万个Ke 3(g)事件和大约9000个辐射事件的数据的比率R = Γ(\keg; \Estar >30 \mev,\qstar >20^ \circ)$/$ Γ(\kegf)$ and a first measurement of the direct emission contribution in KL semileptonic decays. The measurement is done at the DAFNE phi-factory selecting phi->KL KS decays with the KLOE detector. We use 328 pb^{-1}$的测量。我们的结果是R=(924 +/- 23(stat)+/-16(syst)10^{-5}对于分支比和X=-2.3 +/- 1.3(stat)+/- 1.4(syst)对于描述直接发射的参数。
Study of Dalitz decay phi -> eta e+e- with KLOE detector
我们用DAPHNE的KLOE探测器研究了矢量到赝标转换衰变phi -> eta e+e-,其中eta -> pi 0 pi 0 pi 0。在sqrt(s)~Mphi处的1.7 fb-1的e+e-碰撞数据集包含约31,000个事件的清晰转换衰减信号,我们从中测量了BR(phi -> eta e+e-)=(1.075+-0.007+-0.038 x10 -4)的值。使用相同的样品通过拟合e+e不变质谱来确定跃迁形状因子,得到b(phi eta)=(1.17 +-0.10 + 0.07)GeV-2,这将先前测量的精度提高了五倍,并且与VMD预期非常一致。
本文讨论了φ辐射衰变和γ(Ks->pi+pi-(gamma))/γ(Ks-> pi ~(0))比值的KLOE测量。第一个测量的目的是了解标量介子a0和f0的真实性质,它们可能的组成是qq,qqqq或KK分子。第二测量与相移差Δ 0-Δ 2的估计有关。由于辐射效应的存在,以前的测量受到很大的不确定性的影响,这些不确定性正确地包括在我们的分析中。
We present recent results obtained by the KLOE-2 Collaboration at the DAPHNE e+e- collider. The first class of results concerns search for dark forces at the scale of 1 GeV in associated production of gamma and the U boson, in search for the Higgsstrahlung and in possible decays of phi into eta and U. The second is in neutral kaon physics, on testing the CPT and Lorentz invariance, and on search for quantum decoherence effects in entangled pairs of kaons. The third class of results concerns precision measurements in hadronic physics at low energy where transition form factors of phi to pseudos…