Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The longitudinal and transverse distributions of the pion wavefunction
  from the present experimental data on the pion-photon transition form factor   It is noted that the low-energy behavior of the pion-photon transition form
factor $F_{\pi\gamma}(Q^2)$ is sensitive to the transverse distribution of the
pion wavefunction, and its high-energy behavior is sensitive to the
longitudinal one. Thus a careful study on $F_{\pi\gamma}(Q^2)$ can provide
helpful information on the pion wavefunction precisely. In this paper, we
present a combined analysis of the data on $F_{\pi\gamma}(Q^2)$ reported by the
CELLO, the CLEO, the BABAR and the BELLE collaborations. It is performed by
using the method of least squares. By using the combined measurements of BELLE
and CLEO Collaborations, the pion wavefunction longitudinal and transverse
behavior can be fixed to a certain degree, i.e. we obtain $\beta \in
[0.691,0.757] \rm GeV$ and $B \in [0.00,0.235]$ for $P_{\chi^2} \geq 90\%$,
where $\beta$ and $B$ are two parameters of a convenient pion wavefunction
model whose distribution amplitude can mimic the various longitudinal behavior
under proper choice of parameters. We observe that the CELLO, CLEO and BELLE
data are consistent with each other, all of which prefers the asymptotic-like
distribution amplitude; while the BABAR data prefers a more broad distribution
amplitude, such as the CZ-like one.

22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
7
The categories of this paper are: hep-th
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg