摘要:
目前,正负电子湮灭过程的核子激发态
N*产生的实验数据主要来自于粲偶素能区。粲偶素衰变到核子激发态过程类似于其类时电磁形状因子测量过程,正反粲夸克短程湮灭提供了近乎于点源的胶子强子化过程。与
γN,
eN,
πN反应互补,这一新的
N*产生源具有同位旋和低自旋筛选的优势。综述了正负电子湮灭过程的核子激发态
N*产生的实验情况和相关的唯象进展,同时讨论未来发展的一些新方向,如正负电子湮灭过程的核子激发态
N*产物的一些新来源等。
Up to now, the
N* production from
e+e- annihilations has been studied only around charmonium region. Charmonium decays to
N*s are analogous to (time-like) EM form factors in that the charm quark annihilation provides a nearly pointlike (ggg) current. Complementary to other sources, such as
πN,
eN and
γN reactions, this new source for
N* spectroscopy has a few advantages, such as an isospin filter and a low spin filter. The experimental results on
N* from
e+e- annihilations and their phenomenological implications are reviewed. Possible new sources on
N* production from
e+e- annihilations are discussed.