QCD corrections to polarization of and at Tevatron and LHC
May, 2008
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Abstract: (arXiv)
In this work, we present more detail of the calculation on the NLO QCD corrections to polarization of direct J/psi production via color singlet at Tevatron and LHC, as well as the results for Upsilon for the first time. Our results show that the J/psi polarization status drastically changes from transverse polarization dominant at LO into longitudinal polarization dominant in the whole range of the transverse momentum of J/psi when the NLO corrections are counted. For Upsilon production, the p_t distribution of the polarization status behaves almost the same as that for J/psi except that the NLO result is transverse polarization at small p_t range. Although the theoretical evaluation predicts a larger longitudinal polarization than the measured value at Tevatron, it may provide a solution towards the previous large discrepancy for J/psi and Upsilon polarization between theoretical predication and experimental measurement, and suggests that the next important step is to calculate the NLO corrections to hadronproduction of color octet state J/psi^(8) and Upsilon^(8). Our calculations are performed in two ways, namely we do and do not analytically sum over the polarizations, and then check them with each other.Note:
- 11 pages, 6 figures, two columns, use revtex4
- 13.60.Le
- 13.25.Gv
- 12.38.Bx
- p p: inclusive reaction
- anti-p p: annihilation
- J/psi(3100): hadroproduction
- Upsilon(9460): hadroproduction
- direct production
- J/psi(3100): polarization
- Upsilon(9460): polarization
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