ELEMENTARY
PARTICLE SYMBOL*
MASS
MEAN LIFE,
MeV me s
Photon Y 0 0 co
Neutrino v ;^0 0 co
PT
C
Electron e- e+ 0,511^1 co
Muon lc IL+ 105,66 206, 77 2,2.10-6
n+ n- 139,6 273,2 2,55.10-8^
Pions
{
To 135,0 264,2 2.10^16
Kaons {^ K +^ IC 493,8 966,3 1,23.10-8^
ESC K° ko 498,0 974,5
10-10_10-8
Eta meson 71 548, 8^1074 2,4.10-1°
BAR
YON
S
Proton p i 5 938,26 1836,1 co
Neutron n R 939,55 1838,6 1.10-3^
Lambda hyperon A° A° 1115,4 2182,8 2,6.10
-10
r i-^ 1189,4^2328 0,8.104°^
Sigma hyperons /- i+^1197 2342 1,6.104°^
20 io 1192 2333 <10-14
1321 2585 1,7.104°^
Xi hyperons
{ EF:o :: 1314 2572 3.10"^10
Omega hyperon 12 - ir 1675 3278 _leo
- Symbols on the right-hand side denote antiparticles
