This is a beta feature that does not work fully.

Every OSET file must specify information for how Monte Carlo should be generated. The format is

 : accelerator=LHC detector=LHE trigger=L0 montecarlo=Pythia ifsr=on multiint=off mglevel=0

Note the initial ”:”. A line with just ”:” will use default parameter values.

• accelerator= : Currently only LHC is supported.
• detector= : Not yet implemented.
• trigger= : Not yet implemented.
• montecarlo= : Pythia or (beta) MadGraph mode.
• ifsr= : on/off for initial and final state radiation
• multiint= : on/off for multiple interactions
• mglevel= : Not yet implemented.

The format for particles is more or less self evident. Spaces are used to separate arguments, and the colon separates required from optional arguments. Real particles have just one name before the colon, while complex particles have the particle name and the anti-particle name before the colon.

d dbar : pdg=1 charge=-1 color=3 mass=0.33
gamma  : pdg=22 charge=0 color=0 mass=0

• pdg= : The standard PDG code for this particle. This must be set only for particles that are stable or that can be decayed by Pythia.
• charge= : The electromagnetic charge times 3.
• color= : The color representation, 0=color neutral, 3=color fundamental, -3=color anti-fundmental, 8=color adjoint.
• mass= : Mass of the particle, in GeV.
• width= : Width of the particle, in GeV. (Untested, except in single resonance production.)

Every .oset file must contain the relevant standard model particles. The names and properties of these particles should not be changed unless you know what you are doing. Make sure the PDG code matches up with the charge/color/mass of the correct standard model particle, or else you will get unexpected behavior. You do not need to include a standard model particle if it never appears in an production/decay topologies.

d dbar : pdg=1 charge=-1 color=3 mass=0.33
u ubar : pdg=2 charge=2  color=3 mass=0.33
s sbar : pdg=3 charge=-1 color=3 mass=0.5
c cbar : pdg=4 charge=2  color=3 mass=1.5
b bar  : pdg=5 charge=-1 color=3 mass=4.8
t tbar : pdg=6 charge=2  color=3 mass=175.0

e-     e+        : pdg=11 charge=-3 color=0 mass=0.00051
nu_e   nu_ebar   : pdg=12 charge=0  color=0 mass=0.0
mu-    mu+       : pdg=13 charge=-3 color=0 mass=0.10566
nu_mu  nu_mubar  : pdg=14 charge=0  color=0 mass=0.0
tau-   tau+      : pdg=15 charge=-3 color=0 mass=1.777
nu_tau nu_taubar : pdg=16 charge=0  color=0 mass=0.0

g     : pdg=21 charge=0 color=8 mass=0
gamma : pdg=22 charge=0 color=0 mass=0
Z0    : pdg=23 charge=0 color=0 mass=91.188
W+ W- : pdg=24 charge=3 color=0 mass=80.45
h0    : pdg=25 charge=0 color=0 mass=115.0

Currently, MARMOSET can only handle one stable neutral particle. It must be given the PDG code corresponding to the lightest neutralino in SUSY (1000022), it must be a real particle, and it must be charge/color neutral. You can give it any name or mass you want, though.

MPT   : pdg=1000022 charge=0 color=0 mass=300

These particles must not have a PDG code (i.e. pdg=0, which is the default value). They can be given any name that is not currently in use. (We recommend two letter names to avoid possible parsing errors.)

N0      : charge=0  color=0 mass=400
D3  D3~ : charge=-1 color=3 mass=700

Marmoset can handle two-body through five-body decays in principle. A decay is labeled by the particles involved in the decay. In the future you will be able to specify a type of matrix element to use in the decay, but currently decays occur only via phase space. If you wish to name the coefficient in the decay, specify that name after the $ sign.

The five-body decay of pint to p1, p2, p3, p4, and p5 is specified by:

pint > p1 p2 p3 p4 p5 : matrix=0 $ b5

• matrix= : The label of the type of matrix element to use (currently ignored)
• $ : The name of the branching ratio. This does not affect Monte Carlo generation.

You can give multiple decays the same branching ratio name:

X > e+ e- $ b1
X > mu+ mu- $ b1
X > tau+ tau- $ b1

Lepton flavor universality will be enforced for particle X in rate fitting.

Marmoset supports 2→1 and 2→2 production processes. A hard process is label by the initial beams and the produced particles. There are some default matrix elements that you can specify, along with a set of optional arguments. The initial beams can be gluons, or any non-top quark. You can name the hard process coefficient if you wish

g g > D3 D3~ : matrix=1 $ s1

• matrix= : The matrix element to use in the hard process. 1=constant
• A1=, B2=, etc. : Parameters used for specific matrix elements.
• $ : The name of the cross section coefficient. This does not affect Monte Carlo generation.

For 2→1 processes, the only matrix element available is Breit-Wigner. You can specify the width of the particle in the particle definition.

Zprime : charge=0 color=0 mass=1500 width=50
u ubar > Zprime
d dbar > Zprime

• width= : The width of a resonance in GeV.

The order of the entries in the .oset file does not matter. You can intersperse particles, decays, and hard processes. You do not need to specify a particle before specifying its decays. The # sign specifies comments. Blank lines are ignored. You can have arbitrary white space between arugments, but each particle/decay/hard process must end with a hard return.

# My Favorite Particle
Zprime : charge=0 color=0 mass=1500 width=50  # This is ignored.