Onia Processes
- Charmonium 3S1 States
- Charmonium 3PJ States
- Charmonium 3DJ States
- Double Charmonium 3S1 States
- Bottomonium 3S1 States
- Bottomonium 3PJ States
- Bottomonium 3DJ States
- Double Bottomonium 3S1 States
Production of any 3S1, 3PJ, and 3DJ charmonium
and bottomonium states via the colour-singlet and colour-octet
mechanisms. This includes by default, but is not limited to, production of
the 3S1 J/psi and Upsilon and their
radially excited states, as well as the 3PJ chi
states and the 3D1 psi(3770). In each process the
heavy quark content, either ccbar or bbbar, is
followed by a round-bracketed expression which specifies the physical
state in spectroscopic notation, (2S+1) L J. Proceding this
is a square-bracketed expression, also in spectroscopic notation,
which specifies the Fock state through which the process occurs,
where (1) indicates a colour-singlet state and (8) a
colour-octet state.
The unphysical colour-octet states follow the id
scheme of 99 n_q n_s n_r n_L n_J where n_q is the
quark flavour of the state and n_s is the colour-octet state
type. Here 0 is 3S1, 1 is 1S0,
and 2 is 3PJ. All remaining numbers follow the
standard PDG numbering scheme. If a physical state is requested
without a corresponding colour-octet state, a colour-octet state is
automatically added to the ParticleData
when a colour-octet process is selected. The colour-octet state is
created with a mass given by the mass of the physical state plus the
singlet-octet mass splitting parameter Onia:massSplit,
which is by default set at 200 MeV, and decays exclusively
to a gluon and the physical state. If the user wishes to manually
set the mass splitting for each colour-octet state individually
then Onia:forceMassSplit can be set to off.
By default the widths of the octet states are set to vanish.
This is not realistic, given their presumably rather rapid decay,
but a nonvanishing width is not likely to have any measurable
consequences that go beyond what comes from viewing the singlet-octet
mass splitting as an effective parameter.
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by Stefan Wolf [unpublished].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. The expressions for the colour-singlet production of
the 3S1 and 3PJ states can be found
in [Bai83] and [Gas87]. Colour-octet expressions can
be found in [Cho96] for the 1S0, 3S1,
and 3PJ states, and the matrix elements for the 3DJ
states are taken from [Yua98].
The implementation of charmonium and bottomonium production, including
the colour-octet production mechanism, requires information on
long-distance NRQCD matrix elements for the various wavefunctions
involved. Default values for these are encoded in the O
parameters and are taken from [Nas00]; see
also [Bar07]. The 3DJ long-distance matrix elements
are extracted from [Yua98].
Note that states that differ only by the radial excitation number
n_r share the same short-distance matrix elements. The
program has therefore been written such that further radial
excitations can be easily added by editing this file, without
requiring a recompilation of the code. All related arrays must be
expanded in exactly the same way, however, i.e. the code of the colour
singlet state, the long-distance matrix elements and the individual
process on/off switches.
Double production of charmonium and bottomonium 3S1 states is
also available, but with only the colour-singlet processes
included. The short-distance matrix elements for these processes can
be found in [Hum83] and [Qia02]. Arrays seperate to
those used for single charmonium and bottomonium production set the
long-distance NRQCD matrix elements. For consistency these values
should be the same as those provided for single charmonium and
bottomonium production, but are seperated to allow further control by
the user if needed.
The description of
final-state radiation
is in this case based on some further model assumptions.
Most of the processes below are divergent in the limit pT → 0,
and therefore a pTmin scale should be set. Comparisons with
data indicate that this divergence can be tamed the same way as for
the normal QCD 2 → 2 cross sections [Bar07,Kra08],
which makes sense, since they are all dominated by the same kind of
t-channel gluon exchange. It is therefore possible to use the
SuppressSmallPT user hook to impose a
reweighting that cancels the low-pT divergence.
An eikonalized description of these processes is included in the
multiparton-interactions framework. Here the low-pT damping
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-pT limit.
flag Onia:forceMassSplit
(default = on)
Force the mass splitting between the colour-singlet states and their
corresponding colour-octet state to be Onia:massSplit.
parm Onia:massSplit
(default = 0.2; minimum = 0.0; maximum = 1.0)
Mass splitting in GeV between the physical colour-singlet
states and their corresponding colour-octet state.
flag Onia:all
(default = off)
Common switch for the group of onia production.
flag Onia:all(3S1)
(default = off)
Common switch for the group of 3S1 onia production,
e.g. J/psi and Upsilon.
flag Onia:all(3PJ)
(default = off)
Common switch for the group of 3PJ onia production,
e.g. chi_c and chi_b.
flag Onia:all(3DJ)
(default = off)
Common switch for the group of 3DJ onia production,
e.g. psi(3770).
flag Charmonium:all
(default = off)
Common switch for the group of charmonium production,
e.g. J/psi and chi_c.
flag Bottomonium:all
(default = off)
Common switch for the group of bottomonium production,
e.g. Upsilon and chi_b.
Charmonium 3S1 States
Warning: changed fvec, mvec or
pvec values must be provided as a comma-separated list
with the right number of elements, without any blanks inside the list.
mvec Charmonium:states(3S1)
(default = {443,100443}; minimum = 0)
The 3S1 charmonium states that can be produced from the following
processes. Note that all vectors within this section,
either of flags or parameters, must be the same length as this
vector.
pvec Charmonium:O(3S1)[3S1(1)]
(default = {1.16,0.76}; minimum = 0.0)
The colour-singlet long-distance matrix
elements <O[3S1(1)]> for the 3S1 charmonium states.
pvec Charmonium:O(3S1)[3S1(8)]
(default = {0.0119,0.0050}; minimum = 0.0)
The colour-octet long-distance matrix
elements <O[3S1(8)]> for the 3S1 charmonium states.
pvec Charmonium:O(3S1)[1S0(8)]
(default = {0.01,0.004}; minimum = 0.0)
The colour-octet long-distance matrix
elements <O[1S0(8)]> for the 3S1
charmonium states.
pvec Charmonium:O(3S1)[3P0(8)]
(default = {0.01,0.004}; minimum = 0.0)
The colour-octet long-distance matrix
elements <O[3P0(8)]>/m_Q^2 for the 3S1 charmonium
states. The remaining <O[3PJ(8)]>/m_Q^2
are calculated from these long-distance matrix elements.
fvec Charmonium:gg2ccbar(3S1)[3S1(1)]g
(default = {off,off})
Colour-singlet production of 3S1 charmonium states via
g g → ccbar[3S1(1)] g.
Code 401.
fvec Charmonium:gg2ccbar(3S1)[3S1(1)]gm
(default = {off,off})
Colour-singlet production of 3S1 charmonium states via
g g → ccbar[3S1(1)] gamma.
Code 441.
fvec Charmonium:gg2ccbar(3S1)[3S1(8)]g
(default = {off,off})
Colour-octet production of 3S1 charmonium states via
g g → ccbar[3S1(8)] g.
Code 402.
fvec Charmonium:qg2ccbar(3S1)[3S1(8)]q
(default = {off,off})
Colour-octet production of 3S1 charmonium states via
q g → ccbar[3S1(8)] q.
Code 403.
fvec Charmonium:qqbar2ccbar(3S1)[3S1(8)]g
(default = {off,off})
Colour-octet production of 3S1 charmonium states via
q qbar → ccbar[3S1(8)] g.
Code 404.
fvec Charmonium:gg2ccbar(3S1)[1S0(8)]g
(default = {off,off})
Colour-octet production of 3S1 charmonium states via
g g → ccbar[1S0(8)] g.
Code 405.
fvec Charmonium:qg2ccbar(3S1)[1S0(8)]q
(default = {off,off})
Colour-octet production of 3S1 charmonium states via
q g → ccbar[1S0(8)] q.
Code 406.
fvec Charmonium:qqbar2ccbar(3S1)[1S0(8)]g
(default = {off,off})
Colour-octet production of 3S1 charmonium states via
q qbar → ccbar[1S0(8)] g.
Code 407.
fvec Charmonium:gg2ccbar(3S1)[3PJ(8)]g
(default = {off,off})
Colour-octet production of 3S1 charmonium states via
g g → ccbar[3PJ(8)] g.
Code 408.
fvec Charmonium:qg2ccbar(3S1)[3PJ(8)]q
(default = {off,off})
Colour-octet production of 3S1 charmonium states via
q g → ccbar[3PJ(8)] q.
Code 409.
fvec Charmonium:qqbar2ccbar(3S1)[3PJ(8)]g
(default = {off,off})
Colour-octet production of 3S1 charmonium states via
q qbar → ccbar[3PJ(8)] g.
Code 410.
Charmonium 3PJ States
Warning: changed fvec, mvec or
pvec values must be provided as a comma-separated list
with the right number of elements, without any blanks inside the list.
mvec Charmonium:states(3PJ)
(default = {10441,20443,445})
The 3PJ charmonium states that can be produced from the following
processes. Note that all vectors within this section,
either of flags or parameters, must be the same length as this
vector.
pvec Charmonium:O(3PJ)[3P0(1)]
(default = {0.05,0.05,0.05}; minimum = 0.0)
The color-singlet long-distance matrix elements
<O[3P0(1)]>/m_Q^2 for the 3PJ charmonium
states. The remaining <O[3PJ(1)]>/m_Q^2
are calculated from these long-distance matrix elements.
pvec Charmonium:O(3PJ)[3S1(8)]
(default = {0.0031,0.0031,0.0031}; minimum = 0.0)
The color-singlet long-distance matrix elements
<O[3S1(8)]> for the 3PJ charmonium states.
fvec Charmonium:gg2ccbar(3PJ)[3PJ(1)]g
(default = {off,off,off})
Colour-singlet production of 3PJ charmonium states via
g g → ccbar[3PJ(1)] g.
Code 411.
fvec Charmonium:qg2ccbar(3PJ)[3PJ(1)]q
(default = {off,off,off})
Colour-singlet production of 3PJ charmonium states via
q g → ccbar[3PJ(1)] q.
Code 412.
fvec Charmonium:qqbar2ccbar(3PJ)[3PJ(1)]g
(default = {off,off,off})
Colour-singlet production of 3PJ charmonium states via
q qbar → ccbar[3PJ(1)] g.
Code 413.
fvec Charmonium:gg2ccbar(3PJ)[3S1(8)]g
(default = {off,off,off})
Colour-octet production of 3PJ charmonium states via
g g → ccbar[3S1(8)] g.
Code 414.
fvec Charmonium:qg2ccbar(3PJ)[3S1(8)]q
(default = {off,off,off})
Colour-octet production of 3PJ charmonium states via
q g → ccbar[3S1(8)] q.
Code 415.
fvec Charmonium:qqbar2ccbar(3PJ)[3S1(8)]g
(default = {off,off,off})
Colour-octet production of 3PJ charmonium states via
q qbar → ccbar[3S1(8)] g.
Code 416.
Charmonium 3DJ States
Warning: changed fvec, mvec or
pvec values must be provided as a comma-separated list
with the right number of elements, without any blanks inside the list.
mvec Charmonium:states(3DJ)
(default = {30443})
The 3DJ charmonium states that can be produced from the following
processes. Note that all vectors within this section,
either of flags or parameters, must be the same length as this
vector.
pvec Charmonium:O(3DJ)[3D1(1)]
(default = {0.161}; minimum = 0.0)
The color-singlet long-distance matrix elements
<O[3D1(1)]> for the 3PJ charmonium
states. For a 3DJ charmonium state where J is
not 1 the long distance matrix
element <O[3DJ(1)]> is calculated
by (2J+1)<O[3D1(1)]/3> using leading order spin symmetry
relations.
pvec Charmonium:O(3DJ)[3P0(8)]
(default = {0.01}; minimum = 0.0)
The colour-octet long-distance matrix
elements <O[3P0(8)]>/m_Q^2 for the 3DJ charmonium
states. The remaining <O[3PJ(8)]>/m_Q^2
are calculated from these long-distance matrix elements.
fvec Charmonium:gg2ccbar(3DJ)[3DJ(1)]g
(default = {off})
Colour-singlet production of 3PJ charmonium states via
g g → ccbar[3DJ(1)] g.
Code 417.
fvec Charmonium:gg2ccbar(3DJ)[3PJ(8)]g
(default = {off})
Colour-octet production of 3DJ charmonium states via
g g → ccbar[3PJ(8)] g.
Code 418.
fvec Charmonium:qg2ccbar(3DJ)[3PJ(8)]q
(default = {off})
Colour-octet production of 3DJ charmonium states via
q g → ccbar[3PJ(8)] q.
Code 419.
fvec Charmonium:qqbar2ccbar(3DJ)[3PJ(8)]g
(default = {off})
Colour-octet production of 3DJ charmonium states via
q qbar → ccbar[3PJ(8)] g.
Code 420.
Double Charmonium 3S1 States
Warning: changed fvec, mvec or
pvec values must be provided as a comma-separated list
with the right number of elements, without any blanks inside the list.
mvec Charmonium:states(3S1)1
(default = {443,443,100443})
The first 3S1 charmonium states of the charmonium pairs that
can be produced from the following processes. Note that all vectors
within this section, either of modes, flags, or parameters, must be
the same length as this vector.
mvec Charmonium:states(3S1)2
(default = {443,100443,100443})
The second 3S1 charmonium states of the charmonium pairs that
can be produced from the following processes.
pvec Charmonium:O(3S1)[3S1(1)]1
(default = {1.16,1.16,0.76}; minimum = 0.0)
The color-singlet long-distance matrix elements
<O[3S1(1)]> for the first 3S1 charmonium
states.
pvec Charmonium:O(3S1)[3S1(1)]2
(default = {1.16,0.76,0.76}; minimum = 0.0)
The color-singlet long-distance matrix elements
<O[3S1(1)]> for the second 3S1 charmonium
states.
fvec Charmonium:gg2doubleccbar(3S1)[3S1(1)]
(default = {off,off,off})
Colour-singlet production of 3S1 charmonium state pairs via
g g → ccbar[3S1(1)] ccbar[3S1(1)] .
Code 421.
fvec Charmonium:qqbar2doubleccbar(3S1)[3S1(1)]
(default = {off,off,off})
Colour-singlet production of 3S1 charmonium state pairs via
q qbar → ccbar[3S1(1)] ccbar[3S1(1)] .
Code 422.
Bottomonium 3S1 States
Warning: changed fvec, mvec or
pvec values must be provided as a comma-separated list
with the right number of elements, without any blanks inside the list.
mvec Bottomonium:states(3S1)
(default = {553,100553,200553}; minimum = 0)
The 3S1 bottomonium states that can be produced from the following
processes. Note that all vectors within this section,
either of flags or parameters, must be the same length as this
vector.
pvec Bottomonium:O(3S1)[3S1(1)]
(default = {9.28,4.63,3.54}; minimum = 0.0)
The colour-singlet long-distance matrix
elements <O[3S1(1)]> for the 3S1 bottomonium states.
pvec Bottomonium:O(3S1)[3S1(8)]
(default = {0.15,0.045,0.075}; minimum = 0.0)
The colour-octet long-distance matrix
elements <O[3S1(8)]> for the 3S1 bottomonium states.
pvec Bottomonium:O(3S1)[1S0(8)]
(default = {0.02,0.006,0.01}; minimum = 0.0)
The colour-octet long-distance matrix
elements <O[1S0(8)]> for the 3S1
bottomonium states.
pvec Bottomonium:O(3S1)[3P0(8)]
(default = {0.02,0.006,0.01}; minimum = 0.0)
The colour-octet long-distance matrix
elements <O[3P0(8)]>/m_Q^2 for the 3S1 bottomonium
states. The remaining <O[3PJ(8)]>/m_Q^2
are calculated from these long-distance matrix elements.
fvec Bottomonium:gg2bbbar(3S1)[3S1(1)]g
(default = {off,off,off})
Colour-singlet production of 3S1 bottomonium states via
g g → bbbar[3S1(1)] g.
Code 501.
fvec Bottomonium:gg2bbbar(3S1)[3S1(1)]gm
(default = {off,off,off})
Colour-singlet production of 3S1 bottomonium states via
g g → ccbar[3S1(1)] gamma.
Code 551.
fvec Bottomonium:gg2bbbar(3S1)[3S1(8)]g
(default = {off,off,off})
Colour-octet production of 3S1 bottomonium states via
g g → bbbar[3S1(8)] g.
Code 502.
fvec Bottomonium:qg2bbbar(3S1)[3S1(8)]q
(default = {off,off,off})
Colour-octet production of 3S1 bottomonium states via
q g → bbbar[3S1(8)] q.
Code 503.
fvec Bottomonium:qqbar2bbbar(3S1)[3S1(8)]g
(default = {off,off,off})
Colour-octet production of 3S1 bottomonium states via
q qbar → bbbar[3S1(8)] g.
Code 504.
fvec Bottomonium:gg2bbbar(3S1)[1S0(8)]g
(default = {off,off,off})
Colour-octet production of 3S1 bottomonium states via
g g → bbbar[1S0(8)] g.
Code 505.
fvec Bottomonium:qg2bbbar(3S1)[1S0(8)]q
(default = {off,off,off})
Colour-octet production of 3S1 bottomonium states via
q g → bbbar[1S0(8)] q.
Code 506.
fvec Bottomonium:qqbar2bbbar(3S1)[1S0(8)]g
(default = {off,off,off})
Colour-octet production of 3S1 bottomonium states via
q qbar → bbbar[1S0(8)] g.
Code 507.
fvec Bottomonium:gg2bbbar(3S1)[3PJ(8)]g
(default = {off,off,off})
Colour-octet production of 3S1 bottomonium states via
g g → bbbar[3PJ(8)] g.
Code 508.
fvec Bottomonium:qg2bbbar(3S1)[3PJ(8)]q
(default = {off,off,off})
Colour-octet production of 3S1 bottomonium states via
q g → bbbar[3PJ(8)] q.
Code 509.
fvec Bottomonium:qqbar2bbbar(3S1)[3PJ(8)]g
(default = {off,off,off})
Colour-octet production of 3S1 bottomonium states via
q qbar → bbbar[3PJ(8)] g.
Code 510.
Bottomonium 3PJ States
Warning: changed fvec, mvec or
pvec values must be provided as a comma-separated list
with the right number of elements, without any blanks inside the list.
mvec Bottomonium:states(3PJ)
(default = {10551,20553,555})
The 3PJ bottomonium states that can be produced from the following
processes. Note that all vectors within this section,
either of flags or parameters, must be the same length as this
vector.
pvec Bottomonium:O(3PJ)[3P0(1)]
(default = {0.085,0.085,0.085}; minimum = 0.0)
The color-singlet long-distance matrix elements
<O[3P0(1)]>/m_Q^2 for the 3PJ bottomonium
states. The remaining <O[3PJ(1)]>/m_Q^2
are calculated from these long-distance matrix elements.
pvec Bottomonium:O(3PJ)[3S1(8)]
(default = {0.04,0.04,0.04}; minimum = 0.0)
The color-singlet long-distance matrix elements
<O[3S1(8)]> for the 3PJ bottomonium states.
fvec Bottomonium:gg2bbbar(3PJ)[3PJ(1)]g
(default = {off,off,off})
Colour-singlet production of 3PJ bottomonium states via
g g → bbbar[3PJ(1)] g.
Code 511.
fvec Bottomonium:qg2bbbar(3PJ)[3PJ(1)]q
(default = {off,off,off})
Colour-singlet production of 3PJ bottomonium states via
q g → bbbar[3PJ(1)] q.
Code 512.
fvec Bottomonium:qqbar2bbbar(3PJ)[3PJ(1)]g
(default = {off,off,off})
Colour-singlet production of 3PJ bottomonium states via
q qbar → bbbar[3PJ(1)] g.
Code 513.
fvec Bottomonium:gg2bbbar(3PJ)[3S1(8)]g
(default = {off,off,off})
Colour-octet production of 3PJ bottomonium states via
g g → bbbar[3S1(8)] g.
Code 514.
fvec Bottomonium:qg2bbbar(3PJ)[3S1(8)]q
(default = {off,off,off})
Colour-octet production of 3PJ bottomonium states via
q g → bbbar[3S1(8)] q.
Code 515.
fvec Bottomonium:qqbar2bbbar(3PJ)[3S1(8)]g
(default = {off,off,off})
Colour-octet production of 3PJ bottomonium states via
q qbar → bbbar[3S1(8)] g.
Code 516.
Bottomonium 3DJ States
Warning: changed fvec, mvec or
pvec values must be provided as a comma-separated list
with the right number of elements, without any blanks inside the list.
mvec Bottomonium:states(3DJ)
(default = {})
The 3DJ bottomonium states that can be produced from the following
processes. Currently, no 3DJ states are included in the
default ParticleData and so none are included here. Note
that all vectors within this section, either of flags or parameters,
must be the same length as this vector.
pvec Bottomonium:O(3DJ)[3D1(1)]
(default = {}; minimum = 0.0)
The color-singlet long-distance matrix elements
<O[3D1(1)]> for the 3PJ bottomonium
states. For a 3DJ bottomonium state where J is
not 1 the long distance matrix
element <O[3DJ(1)]> is calculated
by (2J+1)<O[3D1(1)]/3> using leading order spin symmetry
relations.
pvec Bottomonium:O(3DJ)[3P0(8)]
(default = {}; minimum = 0.0)
The colour-octet long-distance matrix
elements <O[3P0(8)]>/m_Q^2 for the 3DJ bottomonium
states. The remaining <O[3PJ(8)]>/m_Q^2
are calculated from these long-distance matrix elements.
fvec Bottomonium:gg2bbbar(3DJ)[3DJ(1)]g
(default = {})
Colour-singlet production of 3PJ bottomonium states via
g g → bbbar[3DJ(1)] g.
Code 517.
fvec Bottomonium:gg2bbbar(3DJ)[3PJ(8)]g
(default = {})
Colour-octet production of 3DJ bottomonium states via
g g → bbbar[3PJ(8)] g.
Code 518.
fvec Bottomonium:qg2bbbar(3DJ)[3PJ(8)]q
(default = {})
Colour-octet production of 3DJ bottomonium states via
q g → bbbar[3PJ(8)] q.
Code 519.
fvec Bottomonium:qqbar2bbbar(3DJ)[3PJ(8)]g
(default = {})
Colour-octet production of 3DJ bottomonium states via
q qbar → bbbar[3PJ(8)] g.
Code 520.
Double Bottomonium 3S1 States
Warning: changed fvec, mvec or
pvec values must be provided as a comma-separated list
with the right number of elements, without any blanks inside the list.
mvec Bottomonium:states(3S1)1
(default = {553,553,553,100553,100553,200553})
The first 3S1 bottomonium states of the bottomonium pairs
that can be produced from the following processes. Note that all
vectors within this section, either of modes, flags, or parameters,
must be the same length as this vector.
mvec Bottomonium:states(3S1)2
(default = {553,100553,200553,100553,200553,200553})
The second 3S1 bottomonium states of the bottomonium pairs that
can be produced from the following processes.
pvec Bottomonium:O(3S1)[3S1(1)]1
(default = {9.28,9.28,9.28,4.63,4.63,3.54}; minimum = 0.0)
The color-singlet long-distance matrix elements
<O[3S1(1)]> for the first 3S1 bottomonium
states.
pvec Bottomonium:O(3S1)[3S1(1)]2
(default = {9.28,4.63,3.54,4.63,3.54,3.54}; minimum = 0.0)
The color-singlet long-distance matrix elements
<O[3S1(1)]> for the second 3S1 bottomonium
states.
fvec Bottomonium:gg2doublebbbar(3S1)[3S1(1)]
(default = {off,off,off,off,off,off})
Colour-singlet production of 3S1 bottomonium state pairs via
g g → bbbar[3S1(1)] bbbar[3S1(1)] .
Code 521.
fvec Bottomonium:qqbar2doublebbbar(3S1)[3S1(1)]
(default = {off,off,off,off,off,off})
Colour-singlet production of 3S1 bottomonium state pairs via
q qbar → bbbar[3S1(1)] bbbar[3S1(1)] .
Code 522.