PARTICLE CLASSIFICATION


ELEMENTARY PARTICLES
         Particle                    Anti-     Rest mass Lifetime
Category name              Symbol    particle  (MeV/c^2)   (s)
-------- ----------------- --------- --------- --------- --------
Photon   Photon            gamma     --           0      stable

Leptons  Electron          e-        e+           0.511  stable
         Electron neutrino nu|e      _nu|e        0 *    stable
         Muon              mu-       mu+        105.7    2.20e-6
         Muon neutrino     nu|mu     _nu|mu       0 *    stable
         Tau               tau-      tau+      1784      < 4e-13
         Tau neutrino      nu|tau    _nu|tau      0 *    stable

Hadrons:
Mesons   Pion              pi+       pi-        139.6    2.60e-8
                           pi0       --         135.0    0.83e-16
         Kaon              K+        K-         493.7    1.24e-8
                           K0|S      _K0|S      497.7    0.89e-10
                           K0|L      _K0|L      497.7    5.2e-8
         Eta               eta0      --         548.8    < 1e-18
         D                 D+        D-        1869      9e-13
                           D0        _D0       1865      5e-13
         F                 F+        F-        2021      ~ 2e-13
         J/psi             J/psi     --        3097      ~ 1e-20
         Psi'              psi'      --        3686      ~ 3e-20
         Upsilon           upsilon   --        9460      ~ 1e-20
         B                 B+        B-        5271      ~ 1e-13
                           B0        _B0       5274      ~ 1e-13

Baryons  Proton            p         _p         938.3    stable **
         Neutron           n         _n         939.6    920
         Lambda            lambda0   _lambda0  1115.6    2.6e-10
         Sigma             sigma+    _sigma-   1189.4    0.80e-10
                           sigma0    _sigma0   1192.5    6e-20
                           sigma-    _sigma+   1197.3    1.5e-10
         Xi                xi0       _xi0      1315      2.9e-10
                           xi-       xi+       1321      1.64e-10
         Omega             omega-    omega+    1672      0.82e-10
         Lambda|C          lambda+|C lambda-|C 2280      1e-13


FUNDAMENTAL PARTICLES
Class   Name              Symbol Charge Mass (MeV/c^2) Discovered
------- ----------------- ------ ------ -------------- ----------
Quarks  Up                u      2/3      ~ 100        1963
        Down              d      -1/3     ~ 100        1963
        Charm             c      2/3     ~ 4000        1974
        Strange           s      -1/3     ~ 500        1964
        Top               t      2/3     3-5000 ?      ***
        Bottom            b      -1/3    ~ 5000        1977

Leptons Electron neutrino nu|e   0            0 *      1955
        Electron          e      -1           0.511    1898
        Muon neutrino     nu|mu  0            0 *      1962
        Muon              mu     -1         106        1936
        Tau neutrino      nu|tau 0            0 *      ***
        Tau lepton        tau    -1        1784        1975

Field   Photon            gamma  0            0        1905
quanta  (electromagnetic)
        Intermediate      W+/-   0       80 800        1983
        vector bosons     Z0     0       92 600        1984
        (weak)
        Gluon (strong)    --     0            ?        ***
        Graviton          --     0            0        ***
        (gravity)


*       Physicists have not decisively shown whether or not neutrinos 
        have mass.

**      Grand unified theories predict that protons are unstable and 
        decay; but experiments have shown that, should this be true, 
        the decay rate can be no shorter than 2e32 yr.

***     No discovery date; the named particle has been theorized, but 
        has not yet been experimentally found.

NOTES:  On particle symbology:  A letter (or Greek letter name) is the 
        name of the particle; a +, -, or 0 after the particle 
        indicates a superscripted charge; a | followed by a letter 
        indicates a subscript; and a _ before indicates a bar on top 
        of the particle.  For instance, e- indicates an electron, or

                                       -
                                      e

        while _K0|S indicates
                                      __
                                       0
                                      K
                                       S


                                 -)(-