中文

π+ → e+ ν γ 衰变中介导子轴向型形式因子的精确测量

高能物理 - 实验 2008-11-26 v1

摘要

我们使用 PIBETA 检测器和停止的 π 束流,在三个较宽的运动学区间研究了辐射 π 衰变 π+ → e+ ν γ。基于 42,209 事件的 Dalitz 分布,我们评估了这三个区间中绝对 π → e ν γ 分支比。对积分型和微分型(E(e+),E(γ)E(e+),E(\gamma))分布的最小χ²拟合结果给出介导子轴向型与矢量型弱形式因子之比为 γ=FA/FV=0.443(15)\gamma = F_A/F_V = 0.443(15),或 FA=0.0115(4)F_A = 0.0115(4)(其中 FV=0.0259F_V = 0.0259)。然而,标准模型预测中在高 E(γ)E(\gamma)/低 E(e+)E(e+) 运动学区间的偏离表明仍需进一步的理论和实验工作。

关键词

引用

@article{arxiv.hep-ex/0312029,
  title  = {Precise Measurement of the Pion Axial Form Factor in the Pi+ -> e+ nu gamma Decay},
  author = {E. Frlez and D. Pocanic and V. A. Baranov and W. Bertl and M. Bychkov and N. V. Khomutov and A. S. Korenchenko and S. M. Korenchenko and T. Kozlowski and N. P. Kravchuk and N. A. Kuchinsky and W. Li and R. C. Minehart and D. Mzhavia and B. G. Ritchie and S. Ritt and A. M. Rozhdestvensky and V. V. Sidorkin and L. C. Smith and I. Supek and Z. Tsamalaidze and B. A. VanDevender and E. P. Velicheva and Y. Wang and H. -P. Wirtz and K. O. H. Ziock},
  journal= {arXiv preprint arXiv:hep-ex/0312029},
  year   = {2008}
}

备注

5 pages, 4 figures, 1 table, revtex4