QCD radiative correction to color-octet J/ψ inclusive production at B factories

In nonrelativistic quantum chromodynamics (NRQCD), we study the next-to-leading order (NLO) QCD radiative correction to the color-octet J/psi inclusive production at B factories. Compared with the leading-order (LO) result, the NLO QCD corrections are found to enhance the short-distance coefficients in the color-octet J/psi production e(+)e(-) -> c (c) over bar(S-1(0)(8) or P-3(J)(8))(g) (with J = 0, 1, 2) by a factor of about 1.9. Moreover, the peak at the end point in the J/psi energy distribution predicted at LO can be smeared by the NLO corrections, but the major color-octet contribution still comes from the large energy region of J/psi. By fitting the latest data of sigma(e(+)e(-) -> J/psi + Xnon-c (c) over bar) observed by Belle, we find that the values of color-octet matrix elements are much smaller than expected earlier by using the naive velocity scaling rules or extracted from fitting experimental data with LO calculations. As the most stringent constraint by setting the color-singlet contribution to be zero in e(+)e(-) -> J/psi + Xnon-c (c) over bar, we get an upper limit of the color-octet matrix element, < 0 vertical bar O-J/psi[S-1(0)(8)]vertical bar 0 > + 4.0 < 0 vertical bar O-J/psi[P-3(0)(8)]vertical bar 0 >/m(c)(2) < (2.0 +/- 0.6) x 10(-2) GeV3 at NLO in alpha(s).