Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: $O(\alpha_s v^2)$ correction to $e^+e^-\to J/\psi+\eta_c$ at $B$
  factories   We investigate the ${\mathcal O}(\alpha_s v^2)$ correction to the $e^+e^-\to
J/\psi+\eta_c$ process in the nonrelativistic QCD (NRQCD) factorization
approach. Within some reasonable choices of the relative order-$v^2$ NRQCD
matrix elements, we find that including this new ingredient of correction only
mildly enhances the existing NRQCD predictions. We have also deduced the
asymptotic expressions for the ${\mathcal O}(\alpha_s v^2)$ short-distance
coefficients, and reconfirm the early speculation that at next-to-leading order
in $\alpha_s$, the double logarithm of type $\ln^2 (s/m_c^2)$ appearing in
various NRQCD short-distance coefficients is always associated with the
helicity-suppressed channels.

16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
19
The categories of this paper are: eess
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th