Information on the pion distribution amplitude from the pion-photon transition form factor with the Belle and BABAR data  

作　　者：吴兴刚 黄涛 钟涛 

机构地区：[1]Department of Physics, Chongqing University [2]Institute of High Energy Physics and Theoretical Physics Center for Science Facilities, Chinese Academy of Sciences

出　　处：《Chinese Physics C》2013年第6期36-41,共6页中国物理C（英文版）

基　　金：Supported by Natural Science Foundation of China(10975144,11075225);Program for New Century Excellent Talents in University(NCET-10-0882);Fundamental Research Funds for Central Universities(CQDXWL-2012-Z002)

摘　　要：We perform an analysis of all existing experimental data on the pion-photon transition form factor （TFF）. In the calculation, we include the next-to-leading order correction to the valence-quark contribution and estimate the non-valence-quark contribution by a phenomenological model based on the TFF＇s limiting behavior at both Q^2→0 and Q^2→∞. At present, the pion distribution amplitude （DA） is not definitely determined, it is helpful to have a pion DA model that can mimic all the behaviors suggested in the literature. For the purpose, we adopt the conventional model for pion wavefunction/DA whose broadness is dominantly controlled by a single parameter B. We fix the DA parameters by using the CELLO, CLEO, BABAR and Belle data within small Q^2 region （Q^2≤15 GeV^2）, where all the data are consistent with each other. The pion-photon TFF is then extrapolated into a larger Q^2 region. It is found that we still need more data at a large Q^2 region in order to determine the precise value of B, and we hope that the definite behavior of pion DA can be concluded finally by the consistent data in the coming future.We perform an analysis of all existing experimental data on the pion-photon transition form factor （TFF）. In the calculation, we include the next-to-leading order correction to the valence-quark contribution and estimate the non-valence-quark contribution by a phenomenological model based on the TFF＇s limiting behavior at both Q^2→0 and Q^2→∞. At present, the pion distribution amplitude （DA） is not definitely determined, it is helpful to have a pion DA model that can mimic all the behaviors suggested in the literature. For the purpose, we adopt the conventional model for pion wavefunction/DA whose broadness is dominantly controlled by a single parameter B. We fix the DA parameters by using the CELLO, CLEO, BABAR and Belle data within small Q^2 region （Q^2≤15 GeV^2）, where all the data are consistent with each other. The pion-photon TFF is then extrapolated into a larger Q^2 region. It is found that we still need more data at a large Q^2 region in order to determine the precise value of B, and we hope that the definite behavior of pion DA can be concluded finally by the consistent data in the coming future.

关 键 词：pion distribution amplitude form factor BELLE BABAR 

分 类 号：O572.33[理学—粒子物理与原子核物理]