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CEPC event generation uses WHIZARD generator of version 1.95. Several complete samples of Higgs signal and Standard Model background processes at different energy points, such as 240 GeV, 250 GeV, etc, are generated for CEPC detector R&D and stored on IHEP farm, which can found at /cefs/data/stdhep/CEPCNNN (NNN is energy in GeV).

All these samples will be fed to CEPC full simulation and reconstruction software chain, and the results will be taken as the official samples for physics analysis and detector optimization.

If users want to customized the generation, please use shell script tool at /besfs/groups/higgs/users/moxin/slcio/wz_project/generator to do it by yourself. In the directroy, a detail readme, script, and all necessary suport materials are provided.

Here are some conventions for the generation

  1. e1 is electrons, E1 positron (anti-electron)

  2. e2/E2 are muon- and muon+, e3/E3 tau-/tau+

  3. n1/N1(n2/N2, n3/N3) are neutrino/anti-neutrino of electron (muon/tau)

  4. a is photon

  5. g is gluon

  6. q is any types of quarks (number of types is only limited by phase space)

  7. n is all neutrinos (anti-neutrinos)

  8. 2fermions: e+e- –> fermion anti-fermion (gamma_ISR)

  9. 4fermions: e+e- –> 4fermions final states (gamma_ISR), the classification is quite tricky.

  10. 6fermions: e+e- –> 6fermions final states (gamma_ISR), very complicated but significant at higher energy ( > 300 GeV)

  11. two photon collision [e+e- –> e+e- + (fermion anti-fermion)] samples have huge cross section but usually tiny visible energy, since they are t-channel processes. The generation has large uncertainties and tricky cuts are necessary.