Mattione DMCThrownProblem

Generated Reaction

• γ p → η'₁(2300), p
  • η'₁(2300) → K*(892)⁰, K⁰_bar
    • K*(892)⁰ → K⁺, π^-
      • K⁰_bar → π⁺, π^-

• NOTE: K⁰_bar is decayed by hdgeant rather than the generator!

DMCThrown

• PID Table:
  • PID 4 = Neutrino
  • PID 5 = MuonPlus
  • PID 8 = PiPlus
  • PID 9 = PiMinus
  • PID 11 = KPlus
  • PID 14 = Proton
  • PID 16 = KShort

DMCThrown contents (from hd_dump):

PID:  q: x(cm): y(cm): z(cm): E(GeV): t(ns): p(GeV/c): theta(deg): phi(deg): type: pdgtype: myid: parentid: mech:

---

 11  +1    0.0    0.0   79.8   5.304  0.000     5.281      11.325   -53.603    11      321     1         0     0 
  9  -1    0.0    0.0   79.8   0.379  0.000     0.352      17.746    40.634     9     -211     2         0     0 
 16  +0    0.0    0.0   79.8   3.122  0.000     3.082      11.732   141.844    16      310     3         0     0 
 14  +1    0.0    0.0   79.8   1.133  0.000     0.636      42.469   118.373    14     2212     4         0     0 
  8  +1   -1.0    0.8   85.9   0.455  0.000     0.434      23.577   117.502     8      211     0         3     0 
  9  -1   -1.0    0.8   85.9   2.667  0.000     2.663      10.256   150.514     9     -211     0         3     0 
  5  +1  -65.4    0.7  210.0   0.110  0.000     0.030     113.418   172.483     5      -13     0         3     0 
  4  +0  -65.4    0.7  210.0   0.030  0.000     0.030      66.582    -7.517     4   121416     0         3     0

Discussion

• If a particle is decayed by hdgeant, then the value of "parentid" points to the "myid" that the particle came from. For example, here the π⁺ and π^- are shown with parentid = 3, meaning they came from the K0.

• HOWEVER: note that the muplus and the neutrino ALSO show parentid = 3. This makes it look like the K0 decayed to π⁺, π^-, μ⁺, ν instead of showing the π⁺ decaying to μ⁺, ν Note also that you can't just set the "parentid" of the neutrino to the "myid" of the π⁺ because it is zero, and thus would then look like it was produced by the generator.

• Therefore, "myid" should be set to a unique number for all particles, and "parentid" should be set appropriately for all stages of particle decays in hdgeant.