Valence quark distributions of pion at very low resolution scale Q 2 0 ∼ 0.1 GeV 2 are deduced from a maximum entropy method, under the assumption that pion consists of only a valence quark and a valence anti-quark at such a low scale. Taking the obtained initial quark distributions as the nonperturbative input in the modified Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (with the GLR-MQ-ZRS corrections) evolution, the generated valence quark distribution functions at high Q 2 are consistent with the measured ones from a Drell-Yan experiment. The maximum entropy method is also applied to estimate the valence quark distributions at relatively higher Q 2 = 0.26 GeV 2 . At this higher scale, other components (sea quarks and gluons) should be considered in order to match the experimental data. The first three moments of pion quark distributions at high Q 2 are calculated and compared with the other theoretical predictions.data are performed by several groups, using the nextto-leading-order QCD analysis [8], using the constituent quark model parametrization [9,10], and using the modified DGLAP equations [11].

We study the γp → pf0 [f0(980) and f0(1500)] reaction close to threshold within an effective Lagrangian approach. The production process is described by s-channel nucleon pole or t-channel ρ and ω exchange. The K 0K 0 invariant mass distributions of the γp → f0(980)p → K 0K 0 and γp → f0(1500)p → K 0K 0 p reactions are investigated, where the two kaons have been separated in S wave decaying from f0(980) and f0(1500). It is shown that the s-channel process is favored for the production of f0(980), while for the f0(1500) production, the experimental measurements can be described quite well by the t-channel process. It is expected that the theoretical results can be tested by further experiments at CLAS. PACS numbers: