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Draft: Include general particle names for exotic searches

Miguel Ramos Pernas requested to merge mramospe-general-particles into master

Include particles in ParticleTable.txt to allow the reconstruction of intermediate resonances that can refer to any particle. This covers three main use cases:

  • Decays in which we are interested in the properties of a combination of particles in the decay products of a decay chain without affecting the properties of the parent particle. The most straightforward example is the decay of a particle to two electrons plus additional particles in which we must reconstruct the two electrons avoiding the use of the same bremsstrahlung photons twice (e.g. B^+\to K^+ e^+e^-).
  • Decays where we consider different modes for the same intermediate decay product, which appears more than once in the decay chain (e.g. B^0\to\phi(1020)(\to K^+K^-)\phi(1020)(\to \mu^+\mu^-)).
  • Decays to unknown resonances that might be short- or long-lived, charged or neutral and, in the latter, self-charge-conjugate or not. This would cover decays to particles like intermediate exotic signatures.

By using these particle names we would avoid using unphysical decay chains that are prone to errors if we modify the properties of certain particles, like B^+\to K^+K_L^0(\to e^+e^-) when we want to study long-lived particles in the decay of a B meson (not necessarily a K_L^0) or K^+\to \pi^+ J/\psi(1S)(\to e^+e^-) when we want to combine the two electrons properly. To avoid clashes with the PDG name convention it is considered to use long names with the properties separated by underscores (like LLscc).

Note that these new particles are not physical. Therefore these changes should be independent of simulation and are only meant to be used in the selection of reconstructed objects (e.g. HLT2).

(Old MR lhcb-conddb/DDDB!120 (closed))

Edited by Miguel Ramos Pernas

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