- Standard-Model Higgs, basic processes
- Standard-Model Higgs, further processes
- Beyond-the-Standard-Model Higgs, introduction
- Beyond-the-Standard-Model Higgs, basic processes
- Beyond-the-Standard-Model Higgs, further processes
- Parameters for Beyond-the-Standard-Model Higgs production and decay

`flag `

** Higgs:cubicWidth **
(`default = `

)**off**

The partial width of a Higgs particle to a pair of gauge bosons,
*W^+ W^-* or *Z^0 Z^0*, depends cubically on the
Higgs mass. When selecting the Higgs according to a Breit-Wigner,
so that the actual mass *mHat* does not agree with the
nominal *m_Higgs* one, an ambiguity arises which of the
two to use [Sey95]. The default is to use a linear
dependence on *mHat*, i.e. a width proportional to
*m_Higgs^2 * mHat*, while `on`

gives a
*mHat^3* dependence. This does not affect the widths to
fermions, which only depend linearly on *mHat*.
This flag is used both for SM and BSM Higgs bosons.

`flag `

** Higgs:runningLoopMass **
(`default = `

)**on**

The partial width of a Higgs particle to a pair of gluons or photons,
or a *gamma Z^0* pair, proceeds in part through quark loops,
mainly *b* and *t*. There is some ambiguity what kind
of masses to use. Default is running MSbar ones, but alternatively
fixed pole masses are allowed (as was standard in PYTHIA 6), which
typically gives a noticeably higher cross section for these channels.
(For a decay to a pair of fermions, such as top, the running mass is
used for couplings and the fixed one for phase space.)

`flag `

** Higgs:clipWings **
(`default = `

)**on**

The Breit-Wigner shape of a Higgs is nontrivial, owing to the rapid
width variation with the mass of a Higgs. This implies that a Higgs
of low nominal mass may still acquire a non-negligible high-end tail.
The validity of the calculation may be questioned in these wings.
With this option on, the `Higgs:wingsFac`

value is used to
cut away the wings.
**Warning:** with this option on, the allowed mass range is
shrunk, but never widened. This can lead to inconsistencies if a run
consists of several subruns with different Higgs masses. The
`id:mMin`

and `id:mMax`

values should therefore be
reset (e.g. to the defaults 50. and 0.) when `id:m0`

is
changed.

`parm `

** Higgs:wingsFac **
(`default = `

; **50.**`minimum = 0.`

)

With `Higgs:clipWings`

on, all Higgs masses which deviate
from the nominal one by more than `Higgs:wingsFac`

times the nominal width are forbidden. This is achieved by setting
the `mMin`

and `mMax`

values of the Higgs states
at initialization. These changes never allow a wider range than already
set by the user, alternatively by the current default values, see
warning above.

One setting is specific to the Standard Model:

`flag `

** HiggsSM:NLOWidths **
(`default = `

)**on**

The partial width of the SM Higgs particle are multiplied by the
respective factors needed to bring the LO widths encoded in PYTHIA
to the NLO ones recommended by the LHCXSWG. The multiplicative
factors have been derived for a 125 GeV Higgs, but should apply for a
reasonable mass range around that value.

`ParticleData`

database; thereafter the properties
within the SM are essentially fixed.
`flag `

** HiggsSM:all **
(`default = `

)**off**

Common switch for the group of Higgs production within the Standard Model.

`flag `

** HiggsSM:ffbar2H **
(`default = `

)**off**

Scattering *f fbar → H^0*, where *f* sums over available
flavours except top. Related to the mass-dependent Higgs point coupling
to fermions, so at hadron colliders the bottom contribution will
dominate.
Code 901.

`flag `

** HiggsSM:gg2H **
(`default = `

)**off**

Scattering *g g → H^0* via loop contributions primarily from
top.
Code 902.

`flag `

** HiggsSM:gmgm2H **
(`default = `

)**off**

Scattering *gamma gamma → H^0* via loop contributions primarily
from top and *W*.
Code 903.

`flag `

** HiggsSM:ffbar2HZ **
(`default = `

)**off**

Scattering *f fbar → H^0 Z^0* via *s*-channel *Z^0*
exchange.
Code 904.

`flag `

** HiggsSM:ffbar2HW **
(`default = `

)**off**

Scattering *f fbar → H^0 W^+-* via *s*-channel
*W^+-* exchange.
Code 905.

`flag `

** HiggsSM:ff2Hff(t:ZZ) **
(`default = `

)**off**

Scattering *f f' → H^0 f f'* via *Z^0 Z^0* fusion.
Code 906.

`flag `

** HiggsSM:ff2Hff(t:WW) **
(`default = `

)**off**

Scattering *f_1 f_2 → H^0 f_3 f_4* via *W^+ W^-* fusion.
Code 907.

`flag `

** HiggsSM:gg2Httbar **
(`default = `

)**off**

Scattering *g g → H^0 t tbar* via *t tbar* fusion
(or, alternatively put, Higgs radiation off a top line).
Warning: unfortunately this process is rather slow, owing to a
lengthy cross-section expression and inefficient phase-space selection.
Code 908.

`flag `

** HiggsSM:qqbar2Httbar **
(`default = `

)**off**

Scattering *q qbar → H^0 t tbar* via *t tbar* fusion
(or, alternatively put, Higgs radiation off a top line).
Warning: unfortunately this process is rather slow, owing to a
lengthy cross-section expression and inefficient phase-space selection.
Code 909.

`HiggsSM:all`

flag, but
have to be switched on for each separate process after due consideration.
The first three processes in this section are related to the Higgs
point coupling to fermions, and so primarily are of interest for
*b* quarks. It is here useful to begin by reminding that
a process like *b bbar → H^0* implies that a *b/bbar*
is taken from each incoming hadron, leaving behind its respective
antiparticle. The initial-state showers will then add one
*g → b bbar* branching on either side, so that effectively
the process becomes *g g → H0 b bbar*. This would be the
same basic process as the *g g → H^0 t tbar* one used for top.
The difference is that (a) no PDF's are defined for top and
(b) the shower approach would not be good enough to provide sensible
kinematics for the *H^0 t tbar* subsystem. By contrast, owing
to the *b* being much lighter than the Higgs, multiple
gluon emissions must be resummed for *b*, as is done by PDF's
and showers, in order to obtain a sensible description of the total
production rate, when the *b* quarks predominantly are produced
at small *pT* values.

`flag `

** HiggsSM:qg2Hq **
(`default = `

)**off**

Scattering *q g → H^0 q*. This process gives first-order
corrections to the *f fbar → H^0* one above, and should only be
used to study the high-*pT* tail, while *f fbar → H^0*
should be used for inclusive production. Only the dominant *c*
and *b* contributions are included, and generated separately
for technical reasons. Note that another first-order process would be
*q qbar → H^0 g*, which is not explicitly implemented here,
but is obtained from showering off the lowest-order process. It does not
contain any *b* at large *pT*, however, so is less
interesting for many applications.
Code 911.

`flag `

** HiggsSM:gg2Hbbbar **
(`default = `

)**off**

Scattering *g g → H^0 b bbar*. This process is yet one order
higher of the *b bbar → H^0* and *b g → H^0 b* chain,
where now two quarks should be required above some large *pT*
threshold.
Warning: unfortunately this process is rather slow, owing to a
lengthy cross-section expression and inefficient phase-space selection.
Code 912.

`flag `

** HiggsSM:qqbar2Hbbbar **
(`default = `

)**off**

Scattering *q qbar → H^0 b bbar* via an *s*-channel
gluon, so closely related to the previous one, but typically less
important owing to the smaller rate of (anti)quarks relative to
gluons.
Warning: unfortunately this process is rather slow, owing to a
lengthy cross-section expression and inefficient phase-space selection.
Code 913.

The second set of processes are predominantly first-order corrections
to the *g g → H^0* process, again dominated by the top loop.
We here only provide the kinematical expressions obtained in the
limit that the top quark goes to infinity, but scaled to the
finite-top-mass coupling in *g g → H^0*. (Complete loop
expressions are available e.g. in PYTHIA 6.4 but are very lengthy.)
This provides a reasonably accurate description for "intermediate"
*pT* values, but fails when the *pT* scale approaches
the top mass.

`flag `

** HiggsSM:gg2Hg(l:t) **
(`default = `

)**off**

Scattering *g g → H^0 g* via loop contributions primarily
from top.
Code 914.

`flag `

** HiggsSM:qg2Hq(l:t) **
(`default = `

)**off**

Scattering *q g → H^0 q* via loop contributions primarily
from top. Not to be confused with the `HiggsSM:qg2Hq`

process above, with its direct fermion-to-Higgs coupling.
Code 915.

`flag `

** HiggsSM:qqbar2Hg(l:t) **
(`default = `

)**off**

Scattering *q qbar → H^0 g* via an *s*-channel gluon
and loop contributions primarily from top. Is strictly speaking a
"new" process, not directly derived from *g g → H^0*, and
could therefore be included in the standard mix without double-counting,
but is numerically negligible.
Code 916.

`H1`

for
`H2`

for `A3`

for `Settings`

database does not distinguish upper- and lowercase
characters, so that the user has one thing less to worry about, but here
it causes problems with `flag `

** Higgs:useBSM **
(`default = `

)**off**

Master switch to initialize and use the two-Higgs-doublet states.
If off, only the above SM Higgs processes can be used, with couplings
as predicted in the SM. If on, only the below BSM Higgs processes can
be used, with couplings that can be set freely, also found further down
on this page.

`flag `

** HiggsBSM:all **
(`default = `

)**off**

Common switch for the group of Higgs production beyond the Standard Model,
as listed below.

`flag `

** HiggsBSM:allH1 **
(`default = `

)**off**

Common switch for the group of *h^0(H_1^0)* production processes.

`flag `

** HiggsBSM:ffbar2H1 **
(`default = `

)**off**

Scattering *f fbar → h^0(H_1^0)*, where *f* sums over
available flavours except top.
Code 1001.

`flag `

** HiggsBSM:gg2H1 **
(`default = `

)**off**

Scattering *g g → h^0(H_1^0)* via loop contributions primarily
from top.
Code 1002.

`flag `

** HiggsBSM:gmgm2H1 **
(`default = `

)**off**

Scattering *gamma gamma → h^0(H_1^0)* via loop contributions
primarily from top and *W*.
Code 1003.

`flag `

** HiggsBSM:ffbar2H1Z **
(`default = `

)**off**

Scattering *f fbar → h^0(H_1^0) Z^0* via *s*-channel
*Z^0* exchange.
Code 1004.

`flag `

** HiggsBSM:ffbar2H1W **
(`default = `

)**off**

Scattering *f fbar → h^0(H_1^0) W^+-* via *s*-channel
*W^+-* exchange.
Code 1005.

`flag `

** HiggsBSM:ff2H1ff(t:ZZ) **
(`default = `

)**off**

Scattering *f f' → h^0(H_1^0) f f'* via *Z^0 Z^0* fusion.
Code 1006.

`flag `

** HiggsBSM:ff2H1ff(t:WW) **
(`default = `

)**off**

Scattering *f_1 f_2 → h^0(H_1^0) f_3 f_4* via *W^+ W^-*
fusion.
Code 1007.

`flag `

** HiggsBSM:gg2H1ttbar **
(`default = `

)**off**

Scattering *g g → h^0(H_1^0) t tbar* via *t tbar* fusion
(or, alternatively put, Higgs radiation off a top line).
Warning: unfortunately this process is rather slow, owing to a
lengthy cross-section expression and inefficient phase-space selection.
Code 1008.

`flag `

** HiggsBSM:qqbar2H1ttbar **
(`default = `

)**off**

Scattering *q qbar → h^0(H_1^0) t tbar* via *t tbar*
fusion (or, alternatively put, Higgs radiation off a top line).
Warning: unfortunately this process is rather slow, owing to a
lengthy cross-section expression and inefficient phase-space selection.
Code 1009.

`flag `

** HiggsBSM:allH2 **
(`default = `

)**off**

Common switch for the group of *H^0(H_2^0)* production processes.

`flag `

** HiggsBSM:ffbar2H2 **
(`default = `

)**off**

Scattering *f fbar → H^0(H_2^0)*, where *f* sums over
available flavours except top.
Code 1021.

`flag `

** HiggsBSM:gg2H2 **
(`default = `

)**off**

Scattering *g g → H^0(H_2^0)* via loop contributions primarily
from top.
Code 1022.

`flag `

** HiggsBSM:gmgm2H2 **
(`default = `

)**off**

Scattering *gamma gamma → H^0(H_2^0)* via loop contributions
primarily from top and *W*.
Code 1023.

`flag `

** HiggsBSM:ffbar2H2Z **
(`default = `

)**off**

Scattering *f fbar → H^0(H_2^0) Z^0* via *s*-channel
*Z^0* exchange.
Code 1024.

`flag `

** HiggsBSM:ffbar2H2W **
(`default = `

)**off**

Scattering *f fbar → H^0(H_2^0) W^+-* via *s*-channel
*W^+-* exchange.
Code 1025.

`flag `

** HiggsBSM:ff2H2ff(t:ZZ) **
(`default = `

)**off**

Scattering *f f' → H^0(H_2^0) f f'* via *Z^0 Z^0* fusion.
Code 1026.

`flag `

** HiggsBSM:ff2H2ff(t:WW) **
(`default = `

)**off**

Scattering *f_1 f_2 → H^0(H_2^0) f_3 f_4* via *W^+ W^-*
fusion.
Code 1027.

`flag `

** HiggsBSM:gg2H2ttbar **
(`default = `

)**off**

Scattering *g g → H^0(H_2^0) t tbar* via *t tbar* fusion
(or, alternatively put, Higgs radiation off a top line).
Warning: unfortunately this process is rather slow, owing to a
lengthy cross-section expression and inefficient phase-space selection.
Code 1028.

`flag `

** HiggsBSM:qqbar2H2ttbar **
(`default = `

)**off**

Scattering *q qbar → H^0(H_2^0) t tbar* via *t tbar*
fusion (or, alternatively put, Higgs radiation off a top line).
Warning: unfortunately this process is rather slow, owing to a
lengthy cross-section expression and inefficient phase-space selection.
Code 1029.

`flag `

** HiggsBSM:allA3 **
(`default = `

)**off**

Common switch for the group of *A^0(H_3^0)* production processes.

`flag `

** HiggsBSM:ffbar2A3 **
(`default = `

)**off**

Scattering *f fbar → A^0(H_3^0)*, where *f* sums over
available flavours except top.
Code 1041.

`flag `

** HiggsBSM:gg2A3 **
(`default = `

)**off**

Scattering *g g → A^0(A_3^0)* via loop contributions primarily
from top.
Code 1042.

`flag `

** HiggsBSM:gmgm2A3 **
(`default = `

)**off**

Scattering *gamma gamma → A^0(A_3^0)* via loop contributions
primarily from top and *W*.
Code 1043.

`flag `

** HiggsBSM:ffbar2A3Z **
(`default = `

)**off**

Scattering *f fbar → A^0(A_3^0) Z^0* via *s*-channel
*Z^0* exchange.
Code 1044.

`flag `

** HiggsBSM:ffbar2A3W **
(`default = `

)**off**

Scattering *f fbar → A^0(A_3^0) W^+-* via *s*-channel
*W^+-* exchange.
Code 1045.

`flag `

** HiggsBSM:ff2A3ff(t:ZZ) **
(`default = `

)**off**

Scattering *f f' → A^0(A_3^0) f f'* via *Z^0 Z^0* fusion.
Code 1046.

`flag `

** HiggsBSM:ff2A3ff(t:WW) **
(`default = `

)**off**

Scattering *f_1 f_2 → A^0(A_3^0) f_3 f_4* via *W^+ W^-*
fusion. Code 1047.

`flag `

** HiggsBSM:gg2A3ttbar **
(`default = `

)**off**

Scattering *g g → A^0(A_3^0) t tbar* via *t tbar* fusion
(or, alternatively put, Higgs radiation off a top line).
Warning: unfortunately this process is rather slow, owing to a
lengthy cross-section expression and inefficient phase-space selection.
Code 1048.

`flag `

** HiggsBSM:qqbar2A3ttbar **
(`default = `

)**off**

Scattering *q qbar → A^0(A_3^0) t tbar* via *t tbar*
fusion (or, alternatively put, Higgs radiation off a top line).
Warning: unfortunately this process is rather slow, owing to a
lengthy cross-section expression and inefficient phase-space selection.
Code 1049.

`flag `

** HiggsBSM:allH+- **
(`default = `

)**off**

Common switch for the group of *H^+-* production processes.

`flag `

** HiggsBSM:ffbar2H+- **
(`default = `

)**off**

Scattering *f fbar' → H^+-*, where *f, fbar'* sums over
available incoming flavours. Since couplings are assumed
generation-diagonal, in practice this means *c sbar → H^+*
and *s cbar → H^-*.
Code 1061.

`flag `

** HiggsBSM:bg2H+-t **
(`default = `

)**off**

Scattering *b g → H^+ tbar*. At hadron colliders this is the
dominant process for single-charged-Higgs production.
Code 1062.

`flag `

** HiggsBSM:allHpair **
(`default = `

)**off**

Common switch for the group of Higgs pair-production processes.

`flag `

** HiggsBSM:ffbar2A3H1 **
(`default = `

)**off**

Scattering *f fbar → A^0(H_3) h^0(H_1)*.
Code 1081.

`flag `

** HiggsBSM:ffbar2A3H2 **
(`default = `

)**off**

Scattering *f fbar → A^0(H_3) H^0(H_2)*.
Code 1082.

`flag `

** HiggsBSM:ffbar2H+-H1 **
(`default = `

)**off**

Scattering *f fbar → H^+- h^0(H_1)*.
Code 1083.

`flag `

** HiggsBSM:ffbar2H+-H2 **
(`default = `

)**off**

Scattering *f fbar → H^+- H^0(H_2)*.
Code 1084.

`flag `

** HiggsBSM:ffbar2H+H- **
(`default = `

)**off**

Scattering *f fbar → H+ H-*.
Code 1085.

`flag `

** HiggsBSM:qg2H1q **
(`default = `

)**off**

Scattering *q g → h^0 q*. This process gives first-order
corrections to the *f fbar → h^0* one above, and should only be
used to study the high-*pT* tail, while *f fbar → h^0*
should be used for inclusive production. Only the dominant *c*
and *b* contributions are included, and generated separately
for technical reasons. Note that another first-order process would be
*q qbar → h^0 g*, which is not explicitly implemented here,
but is obtained from showering off the lowest-order process. It does not
contain any *b* at large *pT*, however, so is less
interesting for many applications.
Code 1011.

`flag `

** HiggsBSM:gg2H1bbbar **
(`default = `

)**off**

Scattering *g g → h^0 b bbar*. This process is yet one order
higher of the *b bbar → h^0* and *b g → h^0 b* chain,
where now two quarks should be required above some large *pT*
threshold.
Warning: unfortunately this process is rather slow, owing to a
lengthy cross-section expression and inefficient phase-space selection.
Code 1012.

`flag `

** HiggsBSM:qqbar2H1bbbar **
(`default = `

)**off**

Scattering *q qbar → h^0 b bbar* via an *s*-channel
gluon, so closely related to the previous one, but typically less
important owing to the smaller rate of (anti)quarks relative to
gluons.
Warning: unfortunately this process is rather slow, owing to a
lengthy cross-section expression and inefficient phase-space selection.
Code 1013.

`flag `

** HiggsBSM:gg2H1g(l:t) **
(`default = `

)**off**

Scattering *g g → h^0 g* via loop contributions primarily
from top.
Code 1014.

`flag `

** HiggsBSM:qg2H1q(l:t) **
(`default = `

)**off**

Scattering *q g → h^0 q* via loop contributions primarily
from top. Not to be confused with the `HiggsBSM:qg2H1q`

process above, with its direct fermion-to-Higgs coupling.
Code 1015.

`flag `

** HiggsBSM:qqbar2H1g(l:t) **
(`default = `

)**off**

Scattering *q qbar → h^0 g* via an *s*-channel gluon
and loop contributions primarily from top. Is strictly speaking a
"new" process, not directly derived from *g g → h^0*, and
could therefore be included in the standard mix without double-counting,
but is numerically negligible.
Code 1016.

`flag `

** HiggsBSM:qg2H2q **
(`default = `

)**off**

Scattering *q g → H^0 q*. This process gives first-order
corrections to the *f fbar → H^0* one above, and should only be
used to study the high-*pT* tail, while *f fbar → H^0*
should be used for inclusive production. Only the dominant *c*
and *b* contributions are included, and generated separately
for technical reasons. Note that another first-order process would be
*q qbar → H^0 g*, which is not explicitly implemented here,
but is obtained from showering off the lowest-order process. It does not
contain any *b* at large *pT*, however, so is less
interesting for many applications.
Code 1031.

`flag `

** HiggsBSM:gg2H2bbbar **
(`default = `

)**off**

Scattering *g g → H^0 b bbar*. This process is yet one order
higher of the *b bbar → H^0* and *b g → H^0 b* chain,
where now two quarks should be required above some large *pT*
threshold.
Warning: unfortunately this process is rather slow, owing to a
lengthy cross-section expression and inefficient phase-space selection.
Code 1032.

`flag `

** HiggsBSM:qqbar2H2bbbar **
(`default = `

)**off**

Scattering *q qbar → H^0 b bbar* via an *s*-channel
gluon, so closely related to the previous one, but typically less
important owing to the smaller rate of (anti)quarks relative to
gluons.
Warning: unfortunately this process is rather slow, owing to a
lengthy cross-section expression and inefficient phase-space selection.
Code 1033.

`flag `

** HiggsBSM:gg2H2g(l:t) **
(`default = `

)**off**

Scattering *g g → H^0 g* via loop contributions primarily
from top.
Code 1034.

`flag `

** HiggsBSM:qg2H2q(l:t) **
(`default = `

)**off**

Scattering *q g → H^0 q* via loop contributions primarily
from top. Not to be confused with the `HiggsBSM:qg2H1q`

process above, with its direct fermion-to-Higgs coupling.
Code 1035.

`flag `

** HiggsBSM:qqbar2H2g(l:t) **
(`default = `

)**off**

Scattering *q qbar → H^0 g* via an *s*-channel gluon
and loop contributions primarily from top. Is strictly speaking a
"new" process, not directly derived from *g g → H^0*, and
could therefore be included in the standard mix without double-counting,
but is numerically negligible.
Code 1036.

`flag `

** HiggsBSM:qg2A3q **
(`default = `

)**off**

Scattering *q g → A^0 q*. This process gives first-order
corrections to the *f fbar → A^0* one above, and should only be
used to study the high-*pT* tail, while *f fbar → A^0*
should be used for inclusive production. Only the dominant *c*
and *b* contributions are included, and generated separately
for technical reasons. Note that another first-order process would be
*q qbar → A^0 g*, which is not explicitly implemented here,
but is obtained from showering off the lowest-order process. It does not
contain any *b* at large *pT*, however, so is less
interesting for many applications.
Code 1051.

`flag `

** HiggsBSM:gg2A3bbbar **
(`default = `

)**off**

Scattering *g g → A^0 b bbar*. This process is yet one order
higher of the *b bbar → A^0* and *b g → A^0 b* chain,
where now two quarks should be required above some large *pT*
threshold.
Warning: unfortunately this process is rather slow, owing to a
lengthy cross-section expression and inefficient phase-space selection.
Code 1052.

`flag `

** HiggsBSM:qqbar2A3bbbar **
(`default = `

)**off**

Scattering *q qbar → A^0 b bbar* via an *s*-channel
gluon, so closely related to the previous one, but typically less
important owing to the smaller rate of (anti)quarks relative to
gluons.
Warning: unfortunately this process is rather slow, owing to a
lengthy cross-section expression and inefficient phase-space selection.
Code 1053.

`flag `

** HiggsBSM:gg2A3g(l:t) **
(`default = `

)**off**

Scattering *g g → A^0 g* via loop contributions primarily
from top.
Code 1054.

`flag `

** HiggsBSM:qg2A3q(l:t) **
(`default = `

)**off**

Scattering *q g → A^0 q* via loop contributions primarily
from top. Not to be confused with the `HiggsBSM:qg2H1q`

process above, with its direct fermion-to-Higgs coupling.
Code 1055.

`flag `

** HiggsBSM:qqbar2A3g(l:t) **
(`default = `

)**off**

Scattering *q qbar → A^0 g* via an *s*-channel gluon
and loop contributions primarily from top. Is strictly speaking a
"new" process, not directly derived from *g g → A^0*, and
could therefore be included in the standard mix without double-counting,
but is numerically negligible.
Code 1056.

Masses would be set in the `ParticleData`

database,
while couplings are set below. When possible, the couplings of the Higgs
states are normalized to the corresponding coupling within the SM.
When not, their values within the MSSM are indicated, from which
it should be straightforward to understand what to use instead.
The exception is some couplings that vanish also in the MSSM, where the
normalization has been defined in close analogy with nonvanishing ones.
Some parameter names are asymmetric but crossing can always be used,
i.e. the coupling for *A^0 → H^0 Z^0* obviously is also valid
for *H^0 → A^0 Z^0* and *Z^0 → H^0 A^0*.
Note that couplings usually appear quadratically in matrix elements.

`parm `

** HiggsH1:coup2d **
(`default = `

)**1.**

The *h^0(H_1^0)* coupling to down-type quarks.

`parm `

** HiggsH1:coup2u **
(`default = `

)**1.**

The *h^0(H_1^0)* coupling to up-type quarks.

`parm `

** HiggsH1:coup2l **
(`default = `

)**1.**

The *h^0(H_1^0)* coupling to (charged) leptons.

`parm `

** HiggsH1:coup2Z **
(`default = `

)**1.**

The *h^0(H_1^0)* coupling to *Z^0*.

`parm `

** HiggsH1:coup2W **
(`default = `

)**1.**

The *h^0(H_1^0)* coupling to *W^+-*.

`parm `

** HiggsH1:coup2Hchg **
(`default = `

)**0.**

The *h^0(H_1^0)* coupling to *H^+-* (in loops).
Is *sin(beta - alpha) + cos(2 beta) sin(beta + alpha) /
(2 cos^2theta_W)* in the MSSM.

`parm `

** HiggsH2:coup2d **
(`default = `

)**1.**

The *H^0(H_2^0)* coupling to down-type quarks.

`parm `

** HiggsH2:coup2u **
(`default = `

)**1.**

The *H^0(H_2^0)* coupling to up-type quarks.

`parm `

** HiggsH2:coup2l **
(`default = `

)**1.**

The *H^0(H_2^0)* coupling to (charged) leptons.

`parm `

** HiggsH2:coup2Z **
(`default = `

)**1.**

The *H^0(H_2^0)* coupling to *Z^0*.

`parm `

** HiggsH2:coup2W **
(`default = `

)**1.**

The *H^0(H_2^0)* coupling to *W^+-*.

`parm `

** HiggsH2:coup2Hchg **
(`default = `

)**0.**

The *H^0(H_2^0)* coupling to *H^+-* (in loops).
Is *cos(beta - alpha) + cos(2 beta) cos(beta + alpha) /
(2 cos^2theta_W)* in the MSSM.

`parm `

** HiggsH2:coup2H1H1 **
(`default = `

)**1.**

The *H^0(H_2^0)* coupling to a *h^0(H_1^0)* pair.
Is *cos(2 alpha) cos(beta + alpha) - 2 sin(2 alpha)
sin(beta + alpha)* in the MSSM.

`parm `

** HiggsH2:coup2A3A3 **
(`default = `

)**1.**

The *H^0(H_2^0)* coupling to an *A^0(H_3^0)* pair.
Is *cos(2 beta) cos(beta + alpha)* in the MSSM.

`parm `

** HiggsH2:coup2H1Z **
(`default = `

)**0.**

The *H^0(H_2^0)* coupling to a *h^0(H_1^0) Z^0* pair.
Vanishes in the MSSM.

`parm `

** HiggsH2:coup2A3H1 **
(`default = `

)**0.**

The *H^0(H_2^0)* coupling to an *A^0(H_3^0) h^0(H_1^0)* pair.
Vanishes in the MSSM.

`parm `

** HiggsH2:coup2HchgW **
(`default = `

)**0.**

The *H^0(H_2^0)* coupling to a *H^+- W-+* pair.
Is *sin(beta - alpha)* in the MSSM.

`parm `

** HiggsA3:coup2d **
(`default = `

)**1.**

The *A^0(H_3^0)* coupling to down-type quarks.

`parm `

** HiggsA3:coup2u **
(`default = `

)**1.**

The *A^0(H_3^0)* coupling to up-type quarks.

`parm `

** HiggsA3:coup2l **
(`default = `

)**1.**

The *A^0(H_3^0)* coupling to (charged) leptons.

`parm `

** HiggsA3:coup2H1Z **
(`default = `

)**1.**

The *A^0(H_3^0)* coupling to a *h^0(H_1^0) Z^0* pair.
Is *cos(beta - alpha)* in the MSSM.

`parm `

** HiggsA3:coup2H2Z **
(`default = `

)**1.**

The *A^0(H_3^0)* coupling to a *H^0(H_2^0) Z^0* pair.
Is *sin(beta - alpha)* in the MSSM.

`parm `

** HiggsA3:coup2Z **
(`default = `

)**0.**

The *A^0(H_3^0)* coupling to *Z^0*.
Vanishes in the MSSM.

`parm `

** HiggsA3:coup2W **
(`default = `

)**0.**

The *A^0(H_3^0)* coupling to *W^+-*.
Vanishes in the MSSM.

`parm `

** HiggsA3:coup2H1H1 **
(`default = `

)**0.**

The *A^0(H_3^0)* coupling to a *h^0(H_1^0)* pair.
Vanishes in the MSSM.

`parm `

** HiggsA3:coup2Hchg **
(`default = `

)**0.**

The *A^0(H_3^0)* coupling to *H^+-*.
Vanishes in the MSSM.

`parm `

** HiggsA3:coup2HchgW **
(`default = `

)**1.**

The *A^0(H_3^0)* coupling to a *H^+- W-+* pair.
Is 1 in the MSSM.

`parm `

** HiggsHchg:tanBeta **
(`default = `

)**5.**

The *tan(beta)* value, which leads to an enhancement of the
*H^+-* coupling to down-type fermions and suppression to
up-type ones. The same angle also appears in many other places,
but this particular parameter is only used for the charged-Higgs case.

`parm `

** HiggsHchg:coup2H1W **
(`default = `

)**1.**

The *H^+-* coupling to a *h^0(H_1^0) W^+-* pair.
Is *cos(beta - alpha)* in the MSSM.

`parm `

** HiggsHchg:coup2H2W **
(`default = `

)**0.**

The *H^+-* coupling to a *H^0(H_2^0) W^+-* pair.
Is *sin(beta - alpha)* in the MSSM.

Another set of parameters are not used in the production stage but exclusively for the description of angular distributions in decays.

`mode `

** HiggsH1:parity **
(`default = `

; **1**`minimum = 0`

; `maximum = 4`

)

possibility to modify angular decay correlations in the decay of a
*h^0(H_1)* decay *Z^0 Z^0* or *W^+ W^-* to four
fermions, or *tau^+ tau^-* to any final state. Currently it
does not affect the partial width of the channels, which is only based
on the above parameters.
`option `

** 0** : isotropic decays.
`option `

** 1** : assuming the *h^0(H_1)* is a pure scalar
(CP-even), as in the MSSM.
`option `

** 2** : assuming the *h^0(H_1)* is a pure pseudoscalar
(CP-odd).
`option `

** 3** : assuming the *h^0(H_1)* is a mixture of the two,
including the CP-violating interference term. The parameter
*eta*, see below, sets the strength of the CP-odd admixture,
with the interference term being proportional to *eta*
and the CP-odd one to *eta^2*. Intended for decays into
*W^+ W^-* or *Z^0 Z^0*.
`option `

** 4** : same as `3`

but now *phi*, see
below, sets the CP-mixing angle. The CP-even term is proportional
to *sin^2(phi)*, the interference to *sin(phi)cos(phi)*,
and the CP-odd term to *cos^2(phi)*. Consequently *phi=0* is
pure CP-odd and *phi=pi/2* is pure CP-even. Intended for decays
of *h -> f fbar*, notably for *tau* lepton polarization,
whereas *W^+ W^-* and *Z^0 Z^0* decays are isotropic.

`parm `

** HiggsH1:etaParity **
(`default = `

)**0.**

The *eta* value of CP-violation in the
`HiggsH1:parity = 3`

option.

`parm `

** HiggsH1:phiParity **
(`default = `

)**0.**

The *phi* value of CP-mixing in the
`HiggsH1:parity = 4`

option.

`mode `

** HiggsH2:parity **
(`default = `

; **1**`minimum = 0`

; `maximum = 4`

)

possibility to modify angular decay correlations in the decay of a
*H^0(H_2)* decay *Z^0 Z^0* or *W^+ W^-* to four
fermions, or *tau^+ tau^-* to any final state. Currently it
does not affect the partial width of the channels, which is only based
on the above parameters.
`option `

** 0** : isotropic decays.
`option `

** 1** : assuming the *H^0(H_2)* is a pure scalar
(CP-even), as in the MSSM.
`option `

** 2** : assuming the *H^0(H_2)* is a pure pseudoscalar
(CP-odd).
`option `

** 3** : assuming the *H^0(H_2)* is a mixture of the two,
including the CP-violating interference term. The parameter
*eta*, see below, sets the strength of the CP-odd admixture,
with the interference term being proportional to *eta*
and the CP-odd one to *eta^2*. Intended or decays into
*W^+ W^-* or *Z^0 Z^0*.
`option `

** 4** : same as `3`

but now *phi*, see
below, sets the CP-mixing angle. The CP-even term is proportional
to *sin^2(phi)*, the interference to *sin(phi)cos(phi)*,
and the CP-odd term to *cos^2(phi)*. Consequently *phi=0* is
pure CP-odd and *phi=pi/2* is pure CP-even. Intended for decays
of *H -> f fbar*, notably for *tau* lepton polarization,
whereas *W^+ W^-* and *Z^0 Z^0* decays are isotropic.

`parm `

** HiggsH2:etaParity **
(`default = `

)**0.**

The *eta* value of CP-violation in the
`HiggsH2:parity = 3`

option.

`parm `

** HiggsH2:phiParity **
(`default = `

)**0.**

The *phi* value of CP-mixing in the
`HiggsH2:parity = 4`

option.

`mode `

** HiggsA3:parity **
(`default = `

; **2**`minimum = 0`

; `maximum = 4`

)

possibility to modify angular decay correlations in the decay of a
*A^0(H_3)* decay *Z^0 Z^0* or *W^+ W^-* to four
fermions, or *tau^+ tau^-* to any final state. Currently it
does not affect the partial width of the channels, which is only based
on the above parameters.
`option `

** 0** : isotropic decays.
`option `

** 1** : assuming the *A^0(H_3)* is a pure scalar
(CP-even).
`option `

** 2** : assuming the *A^0(H_3)* is a pure pseudoscalar
(CP-odd), as in the MSSM.
`option `

** 3** : assuming the *A^0(H_3)* is a mixture of the two,
including the CP-violating interference term. The parameter
*eta*, see below, sets the strength of the CP-odd admixture,
with the interference term being proportional to *eta*
and the CP-odd one to *eta^2*. Intended for decays into
*W^+ W^-* or *Z^0 Z^0*.
`option `

** 4** : same as `3`

but now *phi*, see
below, sets the CP-mixing angle. The CP-even term is proportional
to *sin^2(phi)*, the interference to *sin(phi)cos(phi)*,
and the CP-odd term to *cos^2(phi)*. Consequently *phi=0* is
pure CP-odd and *phi=pi/2* is pure CP-even. Intended for decays
of *A -> f fbar*, notably for *tau* lepton polarization,
whereas *W^+ W^-* and *Z^0 Z^0* decays are isotropic.

`parm `

** HiggsA3:etaParity **
(`default = `

)**0.**

The *eta* value of CP-violation in the
`HiggsA3:parity = 3`

option.

`parm `

** HiggsA3:phiParity **
(`default = `

)**0.**

The *phi* value of CP-mixing in the
`HiggsA3:parity = 4`

option.