6,920 research outputs found
QCD corrections to e^+ e^- to J/\psi(\psi(2S))+\chi_{cJ} (J=0,1,2) at B Factories
We analytically calculate the cross sections of double charmonium production
in (J=0,1,2) at next-to-leading order
(NLO) in in nonrelativistic QCD, and confirm factorization of these
processes. In contrast to production, for which the NLO correction
is large and positive, the NLO corrections for production can be
negative, resulting in decreased factors of 0.91 and 0.78 for J=1 and 2
respectively when . Consequently, the NLO QCD corrections
markedly enlarge the difference between cross sections of and
. This may explain why but
not is observed experimentally.
Moreover, for , the NLO QCD corrections
substantially reduce the dependence and lead to predictions with small
theoretical uncertainties.Comment: Version published in PRD, 6 pages, 3 figures, 2 tables, one reference
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J/psi (psi') production at the Tevatron and LHC at O(\alpha_s^4v^4) in nonrelativistic QCD
We present a complete evaluation for \jpsi(\psip) prompt production at the
Tevatron and LHC at next-to-leading order in nonrelativistic QCD, including
color-singlet, color-octet, and higher charmonia feeddown contributions. The
short-distance coefficients of \pj at next-to-leading order are found to be
larger than leading order by more than an order of magnitude but with a minus
sign at high transverse momentum . Two new linear combinations of
color-octet matrix elements are obtained from the CDF data, and used to predict
\jpsi production at the LHC, which agrees with the CMS data. The possibility
of \sa dominance and the \jpsi polarization puzzle are also discussed.Comment: Version published in PRL, 4 pages, 4 figure
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