The Particle Data Group particle code [PDG88,PDG92,PDG00] is
used consistently throughout the program. Almost all known
discrepancies between earlier versions of the PDG standard and the
PYTHIA usage have now been resolved. The one known exception is the
(very uncertain) classification of
, with
also affected as a consequence. There is also a possible point of
confusion in the technicolor sector between
and
. The latter is retained for historical reasons,
whereas the former was introduced for consistency in models of
top-color-assisted technicolor.
The PDG standard, with the local PYTHIA extensions, is referred to as
the KF particle code. This code you have to be thoroughly familiar
with. It is described below.
The KF code is not convenient for a direct storing of masses, decay data, or other particle properties, since the KF codes are so spread out. Instead a compressed code KC between 1 and 500 is used here. A particle and its antiparticle are mapped to the same KC code, but else the mapping is unique. Normally this code is only used at very specific places in the program, not visible to the user. If need be, the correspondence can always be obtained by using the function PYCOMP, i.e. KC = PYCOMP(KF). This mapping is not hardcoded, but can be changed by user intervention, e.g. by introducing new particles with the PYUPDA facility. It is therefore not intended that you should ever want or need to know any KC codes at all. It may be useful to know, however, that for codes smaller than 80, KF and KC agree. Normally a user would never do the inverse mapping, but we note that this is stored as KF = KCHG(KC,4), making use of the KCHG array in the PYDAT2 common block. Of course, the sign of a particle could never be recovered by this inverse operation.
The particle names printed in the tables in this section correspond to the ones obtained with the routine PYNAME, which is used extensively, e.g. in PYLIST. Greek characters are spelt out in full, with a capital first letter to correspond to a capital Greek letter. Generically the name of a particle is made up of the following pieces:
Below follows a list of KF particle codes. The list is not complete; a more extensive one may be obtained with CALL PYLIST(11). Particles are grouped together, and the basic rules are described for each group. Whenever a distinct antiparticle exists, it is given the same KF code with a minus sign (whereas KC codes are always positive).
| KF | Name | Printed | KF | Name | Printed | |
| 1 | d | 11 | e- | |||
| 2 | u | 12 |
|
nu_e | ||
| 3 | s | 13 | mu- | |||
| 4 | c | 14 | nu_mu | |||
| 5 | b | 15 | tau- | |||
| 6 | t | 16 | nu_tau | |||
| 7 | b' | 17 | tau' | |||
| 8 | t' | 18 | nu'_tau | |||
| 9 | 19 | |||||
| 10 | 20 |
| KF | Name | Printed | KF | Name | Printed | |
| 21 | g | 31 | ||||
| 22 | gamma | 32 | Z'0 | |||
| 23 | Z0 | 33 |
|
Z"0 | ||
| 24 | W+ | 34 | W'+ | |||
| 25 | h0 | 35 | H0 | |||
| 26 | 36 | A0 | ||||
| 27 | 37 | H+ | ||||
| 28 | 38 | |||||
| 29 | 39 | Graviton | ||||
| 30 | 40 | |||||
| 41 | R0 | |||||
| 42 |
|
LQ |
| KF | Printed | Meaning | |
| 81 | specflav | Spectator flavour; used in decay-product listings | |
| 82 | rndmflav | A random |
|
| 83 | phasespa | Simple isotropic phase-space decay | |
| 84 | c-hadron | Information on decay of generic charm hadron | |
| 85 | b-hadron | Information on decay of generic bottom hadron | |
| 86 | |||
| 87 | |||
| 88 | junction | A junction of three string pieces | |
| 89 | (internal use for unspecified resonance data) | ||
| 90 | system | Intermediate pseudoparticle in external process | |
| 91 | cluster | Parton system in cluster fragmentation | |
| 92 | string | Parton system in string fragmentation | |
| 93 | indep. | Parton system in independent fragmentation | |
| 94 | CMshower | Four-momentum of time-like showering system | |
| 95 | SPHEaxis | Event axis found with PYSPHE | |
| 96 | THRUaxis | Event axis found with PYTHRU | |
| 97 | CLUSjet | Jet (cluster) found with PYCLUS | |
| 98 | CELLjet | Jet (cluster) found with PYCELL | |
| 99 | table | Tabular output from PYTABU | |
| 100 |
| (14) |
| KF | Name | Printed | KF | Name | Printed | |
| 1103 | dd_1 | |||||
| 2101 | ud_0 | 2103 | ud_1 | |||
| 2203 | uu_1 | |||||
| 3101 |
|
sd_0 | 3103 |
|
sd_1 | |
| 3201 |
|
su_0 | 3203 |
|
su_1 | |
| 3303 |
|
ss_1 |
The flavour-diagonal states are arranged in order of ascending
mass. Thus the obvious generalization of eq. (
)
to
is only valid for charm and bottom.
The lighter quark states can appear mixed, e.g. the
(111) is an equal mixture of
(naively code 111) and
(naively code 221).
The standard rule of having the last digit of the form
is broken for the
-
system,
where it is 0, and this convention should carry over to mixed states
in the
meson system, should one choose to define such. For
higher multiplets with the same spin,
10000,
20000, etc.,
are added to provide the extra distinction needed. Some of the most
frequently used codes are given below.
The full lowest-lying pseudoscalar and vector multiplets are included
in the program, Table
.
| KF | Name | Printed | KF | Name | Printed | |
| 211 | pi+ | 213 | rho+ | |||
| 311 | K0 | 313 |
|
K*0 | ||
| 321 | K+ | 323 |
|
K*+ | ||
| 411 | D+ | 413 |
|
D*+ | ||
| 421 | D0 | 423 |
|
D*0 | ||
| 431 |
|
D_s+ | 433 |
|
D*_s+ | |
| 511 | B0 | 513 |
|
B*0 | ||
| 521 | B+ | 523 |
|
B*+ | ||
| 531 |
|
B_s0 | 533 |
|
B*_s0 | |
| 541 |
|
B_c+ | 543 |
|
B*_c+ | |
| 111 | pi0 | 113 | rho0 | |||
| 221 | eta | 223 | omega | |||
| 331 | eta' | 333 | phi | |||
| 441 | eta_c | 443 |
|
J/psi | ||
| 551 | eta_b | 553 | Upsilon | |||
| 130 |
|
K_L0 | ||||
| 310 |
|
K_S0 |
Also the lowest-lying orbital angular momentum
mesons are
included, Table
: one pseudovector multiplet
obtained for total quark-spin 0 (
)
and one scalar, one pseudovector and one tensor multiplet obtained
for total quark-spin 1 (
or 2),
where
is what is conventionally called the spin
of the meson.
Any mixing between the two pseudovector multiplets is
not taken into account. Please note that some members of these
multiplets have still not been found, and are included here only based
on guesswork. Even for known ones, the information on particles
(mass, width, decay modes) is highly incomplete.
Only two radial excitations are included, the
and
.
| KF | Name | Printed | KF | Name | Printed | |
| 10213 | b_1+ | 10211 |
|
a_0+ | ||
| 10313 |
|
K_10 | 10311 |
|
K*_00 | |
| 10323 |
|
K_1+ | 10321 |
|
K*_0+ | |
| 10413 |
|
D_1+ | 10411 |
|
D*_0+ | |
| 10423 |
|
D_10 | 10421 |
|
D*_00 | |
| 10433 |
|
D_1s+ | 10431 |
|
D*_0s+ | |
| 10113 | b_10 | 10111 |
|
a_00 | ||
| 10223 |
|
h_10 | 10221 |
|
f_00 | |
| 10333 |
|
h'_10 | 10331 |
|
f'_00 | |
| 10443 |
|
h_1c0 | 10441 |
|
chi_0c0 | |
| 20213 |
|
a_1+ | 215 |
|
a_2+ | |
| 20313 |
|
K*_10 | 315 |
|
K*_20 | |
| 20323 |
|
K*_1+ | 325 |
|
K*_2+ | |
| 20413 |
|
D*_1+ | 415 |
|
D*_2+ | |
| 20423 |
|
D*_10 | 425 |
|
D*_20 | |
| 20433 |
|
D*_1s+ | 435 |
|
D*_2s+ | |
| 20113 |
|
a_10 | 115 |
|
a_20 | |
| 20223 |
|
f_10 | 225 |
|
f_20 | |
| 20333 |
|
f'_10 | 335 |
|
f'_20 | |
| 20443 |
|
chi_1c0 | 445 |
|
chi_2c0 | |
| 100443 | psi' | |||||
| 100553 | Upsilon' |
| (16) |
For hadrons with heavy flavours, the root names are Lambda or
Sigma for hadrons with two
or
quarks, Xi for those
with one, and Omega for those without
or
quarks.
Some of the most frequently used codes are given in Table
. The full lowest-lying spin
and
multiplets are included in the program.
| KF | Name | Printed | KF | Name | Printed | |
| 1114 | Delta- | |||||
| 2112 | n0 | 2114 | Delta0 | |||
| 2212 | p+ | 2214 | Delta+ | |||
| 2224 | Delta++ | |||||
| 3112 | Sigma- | 3114 | Sigma*- | |||
| 3122 | Lambda0 | |||||
| 3212 | Sigma0 | 3214 | Sigma*0 | |||
| 3222 | Sigma+ | 3224 | Sigma*+ | |||
| 3312 | Xi- | 3314 | Xi*- | |||
| 3322 | Xi0 | 3324 | Xi*0 | |||
| 3334 | Omega- | |||||
| 4112 |
|
Sigma_c0 | 4114 |
|
Sigma*_c0 | |
| 4122 |
|
Lambda_c+ | ||||
| 4212 |
|
Sigma_c+ | 4214 |
|
Sigma*_c+ | |
| 4222 |
|
Sigma_c++ | 4224 |
|
Sigma*_c++ | |
| 4132 | Xi_c0 | |||||
| 4312 | Xi'_c0 | 4314 |
|
Xi*_c0 | ||
| 4232 | Xi_c+ | |||||
| 4322 | Xi'_c+ | 4324 |
|
Xi*_c+ | ||
| 4332 |
|
Omega_c0 | 4334 |
|
Omega*_c0 | |
| 5112 |
|
Sigma_b- | 5114 |
|
Sigma*_b- | |
| 5122 |
|
Lambda_b0 | ||||
| 5212 |
|
Sigma_b0 | 5214 |
|
Sigma*_b0 | |
| 5222 |
|
Sigma_b+ | 5224 |
|
Sigma*_b+ |
| KF | Printed | Meaning | |
| 110 | reggeon | reggeon
|
|
| 990 | pomeron | pomeron
|
|
| 9900110 | rho_diff0 | Diffractive
|
|
| 9900210 | pi_diffr+ | Diffractive |
|
| 9900220 | omega_di0 | Diffractive |
|
| 9900330 | phi_diff0 | Diffractive |
|
| 9900440 | J/psi_di0 | Diffractive
|
|
| 9902110 | n_diffr | Diffractive |
|
| 9902210 | p_diffr+ | Diffractive |
| KF | Name | Printed | KF | Name | Printed | |
| 1000001 |
|
2000001 |
|
|||
| 1000002 |
|
2000002 |
|
|||
| 1000003 |
|
2000003 |
|
|||
| 1000004 |
|
2000004 |
|
|||
| 1000005 |
|
2000005 |
|
|||
| 1000006 |
|
2000006 |
|
|||
| 1000011 |
|
2000011 |
|
|||
| 1000012 |
|
2000012 |
|
|||
| 1000013 | 2000013 | |||||
| 1000014 |
|
2000014 |
|
|||
| 1000015 | 2000015 | |||||
| 1000016 |
|
2000016 |
|
|||
| 1000021 |
|
1000025 |
|
|||
| 1000022 |
|
1000035 |
|
|||
| 1000023 |
|
1000037 |
|
|||
| 1000024 |
|
1000039 |
|
| KF | Name | Printed | KF | Name | Printed | |
| 3000111 |
|
pi_tc0 | 3100021 |
|
V8_tc | |
| 3000211 |
|
pi_tc+ | 3100111 |
|
pi_22_1_tc | |
| 3000221 |
|
pi'_tc0 | 3200111 |
|
pi_22_8_tc | |
| 3000113 |
|
rho_tc0 | 3100113 |
|
rho_11_tc | |
| 3000213 |
|
rho_tc+ | 3200113 |
|
rho_12_tc | |
| 3000223 |
|
omega_tc0 | 3300113 |
|
rho_21_tc | |
| 3000331 |
|
eta_tc0 | 3400113 |
|
rho_22_tc |
| KF | Name | Printed | KF | Name | Printed | |
| 4000001 | d* | 4000011 | e*- | |||
| 4000002 | u* | 4000012 |
|
nu*_e0 |
| KF | Name | Printed | KF | Name | Printed | |
| 5000039 | Graviton* | |||||
| 9900012 |
|
nu_Re | 9900023 |
|
Z_R0 | |
| 9900014 | nu_Rmu | 9900024 |
|
W_R+ | ||
| 9900016 | nu_Rtau | 9900041 | H_L++ | |||
| 9900042 | H_R++ |
A hint on large particle numbers: if you want to avoid mistyping
the number of zeros, it may pay off to define a statement like
PARAMETER (KSUSY1=1000000,KSUSY2=2000000,KTECHN=3000000,
&KEXCIT=4000000,KDIMEN=5000000)