2,287 research outputs found
Quarkonium Production in an Improved Color Evaporation Model
We propose an improved version of the color evaporation model to describe
heavy quarkonium production. In contrast to the traditional color evaporation
model, we impose the constraint that the invariant mass of the intermediate
heavy quark-antiquark pair to be larger than the mass of produced quarkonium.
We also introduce a momentum shift between heavy quark-antiquark pair and the
quarkonium. Numerical calculations show that our model can describe the
charmonium yields as well as ratio of over better than
the traditional color evaporation model.Comment: 6 pages, 4 figure
polarization in the CGC+NRQCD approach
We compute the polarization observables ,
, in a Color Glass Condensate (CGC) +
nonrelativistic QCQ (NRQCD) formalism that includes contributions from both
color singlet and color octet intermediate states. Our results are compared to
low data on polarization from the LHCb and ALICE experiments on
proton-proton collisions at center-of-mass energies of TeV and 8
TeV. Our CGC+NRQCD computation provides a better description of data for GeV relative to extant next-to-leading (NLO) calculations within the
collinear factorization framework. These results suggest that higher order
computations in the CGC+NRQCD framework have the potential to greatly improve
the accuracy of extracted values of the NRQCD universal long distance matrix
elements.Comment: 26 pages, 8 figures, accepted for publication in JHE
production and suppression in high energy proton-nucleus collisions
We apply a Color Glass Condensate+Non-Relativistic QCD (CGC+NRQCD) framework
to compute production in deuteron-nucleus collisions at RHIC and
proton-nucleus collisions at the LHC. Our results match smoothly at high
to a next-to-leading order perturbative QCD + NRQCD computation.
Excellent agreement is obtained for spectra at RHIC and LHC for
central and forward rapidities, as well as for the normalized ratio of
these results to spectra in proton-proton collisions. In particular, we observe
that the data is strongly bounded by our computations of the same for
each of the individual NRQCD channels; this result provides strong evidence
that our description is robust against uncertainties in initial conditions and
hadronization mechanisms.Comment: 7 pages, 4 figure
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