<s>
Event	B-Algorithm
generators	I-Algorithm
are	O
software	B-Library
libraries	I-Library
that	O
generate	O
simulated	O
high-energy	O
particle	O
physics	O
events	O
.	O
</s>
<s>
Events	O
come	O
in	O
different	O
types	O
called	O
processes	O
as	O
discussed	O
in	O
the	O
Automatic	B-Application
calculation	I-Application
of	I-Application
particle	I-Application
interaction	I-Application
or	I-Application
decay	I-Application
article	O
.	O
</s>
<s>
Despite	O
the	O
simple	O
structure	O
of	O
the	O
tree-level	O
perturbative	O
quantum	O
field	O
theory	O
description	O
of	O
the	O
collision	O
and	O
decay	O
processes	O
in	O
an	O
event	O
,	O
the	O
observed	O
high-energy	O
process	O
usually	O
contains	O
significant	O
amount	O
of	O
modifications	O
,	O
like	O
photon	B-Application
and	O
gluon	O
bremsstrahlung	O
or	O
loop	O
diagram	O
corrections	O
,	O
that	O
usually	O
are	O
too	O
complex	O
to	O
be	O
easily	O
evaluated	O
in	O
real	O
calculations	O
directly	O
on	O
the	O
diagrammatic	O
level	O
.	O
</s>
<s>
Based	O
on	O
the	O
fact	O
that	O
in	O
most	O
processes	O
a	O
factorization	O
of	O
the	O
full	O
process	O
into	O
individual	O
problems	O
is	O
possible	O
(	O
which	O
means	O
a	O
negligible	O
effect	O
from	O
interference	O
)	O
,	O
these	O
individual	O
processes	O
are	O
calculated	O
separately	O
,	O
and	O
the	O
probabilistic	O
branching	O
between	O
them	O
are	O
performed	O
using	O
Monte	B-Algorithm
Carlo	I-Algorithm
methods	I-Algorithm
.	O
</s>
<s>
The	O
final-state	O
particles	O
generated	O
by	O
event	B-Algorithm
generators	I-Algorithm
can	O
be	O
fed	O
into	O
the	O
detector	O
simulation	O
,	O
allowing	O
a	O
precise	O
prediction	O
and	O
verification	O
for	O
the	O
entire	O
system	O
of	O
experimental	O
setup	O
.	O
</s>
<s>
However	O
,	O
as	O
the	O
detector	O
simulation	O
is	O
usually	O
a	O
complex	O
and	O
computationally	O
expensive	O
task	O
,	O
simple	O
event	O
analysis	O
techniques	O
are	O
also	O
performed	O
directly	O
on	O
event	B-Algorithm
generator	I-Algorithm
results	O
.	O
</s>
<s>
Some	O
automatic	O
software	O
packages	O
exist	O
,	O
that	O
help	O
in	O
constructing	O
event	B-Algorithm
generators	I-Algorithm
and	O
are	O
sometimes	O
viewed	O
as	O
generators	O
of	O
event	B-Algorithm
generators	I-Algorithm
or	O
meta-generators	O
.	O
</s>
<s>
Partly	O
due	O
to	O
historic	O
reasons	O
,	O
most	O
event	B-Algorithm
generators	I-Algorithm
are	O
written	O
in	O
FORTRAN	O
77	O
,	O
with	O
a	O
few	O
C++	B-Language
generators	O
slowly	O
emerging	O
in	O
recent	O
years	O
.	O
</s>
<s>
The	O
Particle	O
Data	O
Group	O
maintains	O
a	O
standard	O
for	O
designating	O
Standard	B-General_Concept
Model	I-General_Concept
particles	O
and	O
resonances	B-Application
with	O
integer	O
codes	O
in	O
event	B-Algorithm
generators	I-Algorithm
(	O
also	O
known	O
as	O
the	O
"	O
PDG	O
code	O
"	O
)	O
.	O
</s>
<s>
A	O
typical	O
hadronic	O
event	B-Algorithm
generator	I-Algorithm
simulates	O
the	O
following	O
subprocesses	O
:	O
</s>
<s>
A	O
typical	O
heavy-ion	O
event	B-Algorithm
generator	I-Algorithm
usually	O
can	O
be	O
less	O
strict	O
in	O
simulating	O
the	O
rare	O
and	O
rather	O
negligible	O
processes	O
found	O
in	O
a	O
hadronic	O
generator	O
,	O
but	O
would	O
need	O
to	O
simulate	O
the	O
following	O
subprocesses	O
,	O
in	O
addition	O
to	O
those	O
in	O
a	O
hadronic	O
generator	O
:	O
</s>
<s>
The	O
major	O
event	B-Algorithm
generators	I-Algorithm
that	O
are	O
used	O
by	O
current	O
experiments	O
are	O
:	O
</s>
