+++ /dev/null
-<chapter name="Onia Processes">
-
-<h2>Onia Processes</h2>
-
-Production of J/psi or Upsilon, directly and via chi states and the
-colour-octet mechanism.
-In each process the square-bracketed expression specifies the state
-in spectroscopic notation, <ei>(2S+1) L J</ei>, followed by
-<ei>(1)</ei> for colour-singlet states and <ei>(8)</ei> for
-colour-octet ditto.
-
-<p/>
-The original Fortran code for these processes has been contributed
-by Stefan Wolf [unpublished]. For the C++ version only the unpolarized
-expressions are retained, since the theoretical predictions of the
-colour-octet model anyway do not agree with the experimental
-observations. Furthermore, the polarization effects are modest,
-so isotropic decay is not a bad starting point. Such an event sample
-can afterwards be reweighted at will by the user, to test various
-assumptions.
-
-<p/>
-The description of
-<aloc href="TimelikeShowers">final-state radiation</aloc>
-is in this case based on some further model assumptions.
-
-<p/>
-Most of the processes below are divergent in the limit <ei>pT -> 0</ei>,
-and therefore a <ei>pTmin</ei> scale should be set. Comparisons with
-data indicate that this divergence can be tamed the same way as for
-the normal QCD <ei>2 -> 2</ei> cross sections <ref>Bar06,Kra08</ref>,
-which makes sense, since they are all dominated by the same kind of
-<ei>t</ei>-channel gluon exchange. It is therefore possible to use the
-<aloc href="UserHooks">SuppressSmallPT</aloc> user hook to impose a
-reweighting that cancels the low-<ei>pT</ei> divergence.
-
-<p/>
-An eikonalized description of these processes is included in the
-multiparton-interactions framework. Here the low-<ei>pT</ei> dampening
-is automatic, and additionally the framework is more consistent
-(e.g. with respect to energy-momentum constraints and the
-impact-parameter description) for events where the onium production
-is not the hardest subprocess, as would often be the case in the
-low-<ei>pT</ei> limit.
-
-<h3>Charmonium</h3>
-
-<flag name="Charmonium:all" default="off">
-Common switch for the group of charmonium production.
-</flag>
-
-<flag name="Charmonium:gg2QQbar[3S1(1)]g" default="off">
-<ei>g g -> ccbar[3S1(1)] g</ei>.
-Code 401.
-</flag>
-
-<flag name="Charmonium:gg2QQbar[3P0(1)]g" default="off">
-<ei>g g -> ccbar[3P0(1)] g</ei>.
-Code 402.
-</flag>
-
-<flag name="Charmonium:gg2QQbar[3P1(1)]g" default="off">
-<ei>g g -> ccbar[3P1(1)] g</ei>.
-Code 403.
-</flag>
-
-<flag name="Charmonium:gg2QQbar[3P2(1)]g" default="off">
-<ei>g g -> ccbar[3P2(1)] g</ei>.
-Code 404.
-</flag>
-
-<flag name="Charmonium:qg2QQbar[3P0(1)]q" default="off">
-<ei>q g -> ccbar[3P0(1)] q</ei>.
-Code 405.
-</flag>
-
-<flag name="Charmonium:qg2QQbar[3P1(1)]q" default="off">
-<ei>q g -> ccbar[3P1(1)] q</ei>.
-Code 406.
-</flag>
-
-<flag name="Charmonium:qg2QQbar[3P2(1)]q" default="off">
-<ei>q g -> ccbar[3P2(1)] q</ei>.
-Code 407.
-</flag>
-
-<flag name="Charmonium:qqbar2QQbar[3P0(1)]g" default="off">
-<ei>q qbar -> ccbar[3P0(1)] g</ei>.
-Code 408.
-</flag>
-
-<flag name="Charmonium:qqbar2QQbar[3P1(1)]g" default="off">
-<ei>q qbar -> ccbar[3P1(1)] g</ei>.
-Code 409.
-</flag>
-
-<flag name="Charmonium:qqbar2QQbar[3P2(1)]g" default="off">
-<ei>q qbar -> ccbar[3P2(1)] g</ei>.
-Code 410.
-</flag>
-
-<flag name="Charmonium:gg2QQbar[3S1(8)]g" default="off">
-<ei>g g -> ccbar[3S1(8)] g</ei>.
-Code 411.
-</flag>
-
-<flag name="Charmonium:gg2QQbar[1S0(8)]g" default="off">
-<ei>g g -> ccbar[3S1(8)] g</ei>.
-Code 412.
-</flag>
-
-<flag name="Charmonium:gg2QQbar[3PJ(8)]g" default="off">
-<ei>g g -> ccbar[3S1(8)] g</ei>.
-Code 413.
-</flag>
-
-<flag name="Charmonium:qg2QQbar[3S1(8)]q" default="off">
-<ei>q g -> ccbar[3S1(8)] q</ei>.
-Code 414.
-</flag>
-
-<flag name="Charmonium:qg2QQbar[1S0(8)]q" default="off">
-<ei>q g -> ccbar[3S1(8)] q</ei>.
-Code 415.
-</flag>
-
-<flag name="Charmonium:qg2QQbar[3PJ(8)]q" default="off">
-<ei>q g -> ccbar[3S1(8)] q</ei>.
-Code 416.
-</flag>
-
-<flag name="Charmonium:qqbar2QQbar[3S1(8)]g" default="off">
-<ei>q qbar -> ccbar[3S1(8)] g</ei>.
-Code 417.
-</flag>
-
-<flag name="Charmonium:qqbar2QQbar[1S0(8)]g" default="off">
-<ei>q qbar -> ccbar[3S1(8)] g</ei>.
-Code 418.
-</flag>
-
-<flag name="Charmonium:qqbar2QQbar[3PJ(8)]g" default="off">
-<ei>q qbar -> ccbar[3S1(8)] g</ei>.
-Code 419.
-</flag>
-
-<h3>Bottomonium</h3>
-
-<flag name="Bottomonium:all" default="off">
-Common switch for the group of charmonium production.
-</flag>
-
-<flag name="Bottomonium:gg2QQbar[3S1(1)]g" default="off">
-<ei>g g -> bbbar[3S1(1)] g</ei>.
-Code 501.
-</flag>
-
-<flag name="Bottomonium:gg2QQbar[3P0(1)]g" default="off">
-<ei>g g -> bbbar[3P0(1)] g</ei>.
-Code 502.
-</flag>
-
-<flag name="Bottomonium:gg2QQbar[3P1(1)]g" default="off">
-<ei>g g -> bbbar[3P1(1)] g</ei>.
-Code 503.
-</flag>
-
-<flag name="Bottomonium:gg2QQbar[3P2(1)]g" default="off">
-<ei>g g -> bbbar[3P2(1)] g</ei>.
-Code 504.
-</flag>
-
-<flag name="Bottomonium:qg2QQbar[3P0(1)]q" default="off">
-<ei>q g -> bbbar[3P0(1)] q</ei>.
-Code 505.
-</flag>
-
-<flag name="Bottomonium:qg2QQbar[3P1(1)]q" default="off">
-<ei>q g -> bbbar[3P1(1)] q</ei>.
-Code 506.
-</flag>
-
-<flag name="Bottomonium:qg2QQbar[3P2(1)]q" default="off">
-<ei>q g -> bbbar[3P2(1)] q</ei>.
-Code 507.
-</flag>
-
-<flag name="Bottomonium:qqbar2QQbar[3P0(1)]g" default="off">
-<ei>q qbar -> bbbar[3P0(1)] g</ei>.
-Code 508.
-</flag>
-
-<flag name="Bottomonium:qqbar2QQbar[3P1(1)]g" default="off">
-<ei>q qbar -> bbbar[3P1(1)] g</ei>.
-Code 509.
-</flag>
-
-<flag name="Bottomonium:qqbar2QQbar[3P2(1)]g" default="off">
-<ei>q qbar -> bbbar[3P2(1)] g</ei>.
-Code 510.
-</flag>
-
-<flag name="Bottomonium:gg2QQbar[3S1(8)]g" default="off">
-<ei>g g -> bbbar[3S1(8)] g</ei>.
-Code 511.
-</flag>
-
-<flag name="Bottomonium:gg2QQbar[1S0(8)]g" default="off">
-<ei>g g -> bbbar[3S1(8)] g</ei>.
-Code 512.
-</flag>
-
-<flag name="Bottomonium:gg2QQbar[3PJ(8)]g" default="off">
-<ei>g g -> bbbar[3S1(8)] g</ei>.
-Code 513.
-</flag>
-
-<flag name="Bottomonium:qg2QQbar[3S1(8)]q" default="off">
-<ei>q g -> bbbar[3S1(8)] q</ei>.
-Code 514.
-</flag>
-
-<flag name="Bottomonium:qg2QQbar[1S0(8)]q" default="off">
-<ei>q g -> bbbar[3S1(8)] q</ei>.
-Code 515.
-</flag>
-
-<flag name="Bottomonium:qg2QQbar[3PJ(8)]q" default="off">
-<ei>q g -> bbbar[3S1(8)] q</ei>.
-Code 516.
-</flag>
-
-<flag name="Bottomonium:qqbar2QQbar[3S1(8)]g" default="off">
-<ei>q qbar -> bbbar[3S1(8)] g</ei>.
-Code 517.
-</flag>
-
-<flag name="Bottomonium:qqbar2QQbar[1S0(8)]g" default="off">
-<ei>q qbar -> bbbar[3S1(8)] g</ei>.
-Code 518.
-</flag>
-
-<flag name="Bottomonium:qqbar2QQbar[3PJ(8)]g" default="off">
-<ei>q qbar -> bbbar[3S1(8)] g</ei>.
-Code 519.
-</flag>
-
-<h3>Onium matrix elements</h3>
-
-The implementation of charmonium and bottomonium production, including
-the colour-octet production mechanism, requires information on NRQCD
-matrix elements for the various wavefunctions involved. Default values
-for these are encoded in the following ten variables. They
-are taken from <ref>Nas00</ref>; see also <ref>Bar06</ref>.
-
-<parm name="Charmonium:OJpsi3S11" default="1.16" min="0.0">
-<ei><O(J/psi)[3S1(1)]></ei>.
-</parm>
-
-<parm name="Charmonium:OJpsi3S18" default="0.0119" min="0.0">
-<ei><O(J/psi)[3S1(8)]></ei>.
-</parm>
-
-<parm name="Charmonium:OJpsi1S08" default="0.01" min="0.0">
-<ei><O(J/psi)[1S0(8)]></ei>.
-</parm>
-
-<parm name="Charmonium:OJpsi3P08" default="0.01" min="0.0">
-<ei><O(J/psi)[3P0(8)]>/m_c^2</ei>.
-</parm>
-
-<parm name="Charmonium:Ochic03P01" default="0.05" min="0.0">
-<ei><O(chi_c0)[3P0(8)]>/m_c^2</ei>.
-</parm>
-
-<parm name="Bottomonium:OUpsilon3S11" default="9.28" min="0.0">
-<ei><O(Upsilon)[3S1(1)]></ei>.
-</parm>
-
-<parm name="Bottomonium:OUpsilon3S18" default="0.15" min="0.0">
-<ei><O(Upsilon)[3S1(8)]></ei>.
-</parm>
-
-<parm name="Bottomonium:OUpsilon1S08" default="0.02" min="0.0">
-<ei><O(Upsilon)[1S0(8)]></ei>.
-</parm>
-
-<parm name="Bottomonium:OUpsilon3P08" default="0.02" min="0.0">
-<ei><O(Upsilon)[3P0(8)]>/m_b^2</ei>.
-</parm>
-
-<parm name="Bottomonium:Ochib03P01" default="0.085" min="0.0">
-<ei><O(chi_b0)[3P0(8)]>/m_b^2</ei>.
-</parm>
-
-
-</chapter>
-
-<!-- Copyright (C) 2012 Torbjorn Sjostrand -->
-
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