Finding a Way to Determine the Pion Distribution Amplitude from the Experimental Data
HUANG Tao1, WU Xing-Gang2, ZHONG Tao1
1Institute of High Energy Physics and Theoretical Physics Center for Science Facilities, Chinese Academy of Sciences, Beijing 100049 2Department of Physics, Chongqing University, Chongqing 401331
It is believed that one can extract more accurate information of the pion distribution amplitude from the pion-photon transition form factor (TFF) due to the single pion in this process. However, the BABAR and Belle data of the pion-photon TFF have a big difference for Q2∈[15,40] GeV2, and at present, the pion DA can not be definitely determined from the pion-photon TFF. It is crucial to find the right pion DA behavior and to determine which data is more reliable. We perform a combined analysis of the most existing data of the processes involving pion by using a general model for the pion wavefunction/DA. Such a DA model can mimic all the existed pion DA behaviors, whose parameters can be fixed by the constraints from the processes π0→γγ, π→μν, and B→πl ν, etc. Especially, we examine the B →π transition form factors that provides another constraint to the parameter B in our DA model, which results in B∈[0.00,0.29]. This inversely shows that the predicted curve for the pion-photon TFF is between the BABAR and Belle data in the region Q2∈[15,40] GeV2. It will be tested by coming more accurate data in large Q2 region, and the definite behavior of pion DA can be concluded finally.
. [J]. 中国物理快报, 2013, 30(4): 41201-041201.
HUANG Tao, WU Xing-Gang, ZHONG Tao. Finding a Way to Determine the Pion Distribution Amplitude from the Experimental Data. Chin. Phys. Lett., 2013, 30(4): 41201-041201.
2013, Vol. 30 
