Decay Kinematics

Table I.- Decay modes for pions and kaons.- For 2-body decay, p is the momentum of each decay product in the rest frame of the decaying particle. (For a 3-body decay, p is the largest momentum any of the products can have in this frame.) (From Review of Particle Properties, first 4 columns in table below.)

The last 4 columns give the following information for the charged particle product in the 2-body decay, for incident momenta of P(lab) = 0.2, 0.5, 1.0 and 2.0 GeV/c).

-- the maximum emitting polar angle in the lab w/r to the momentum of the decaying particle)

-- minimum lab momentum

-- maximum lab momentum.

Assuming isotropic decay in the rest frame of the decaying particle, we obtain a mostly uniform distribution in the lab frame between the minimum and maximum mome

                                           P(lab) GeV/c
                                       |-----------------------|
Particle Decay modes Fraction p(GeV/c)  0.2   0.5   1.0    2.0

pi+   mu+ neutrino_mu 99.99%  0.030     11deg 4.5deg 2.2deg 1.1deg
                                        0.11  0.28   0.57   1.14
                                        0.21  0.50   1.01   2.00


ka+   mu+ neutrino_mu 63.51%  0.236      180   180    180   33deg
                                        0.15  0.07   0.01   0.06
                                        0.36  0.60   1.06   2.03

ka+     pi+ pio       21.16%  0.205      180   180     66   21deg
                                        0.12  0.04   0.05   0.15
                                        0.32  0.55   0.94   1.75

ka+    pi+ pi+ pi-     5.59%  0.125
       pi+ pio pio     1.73%  0.133
   pio mu+ neutrino_mu 3.18%  0.215
   pio e+ neutrino_e   4.82%  0.228