New line for Lc to pKKpi0 and modifications to PentaToPhiPp line

The name of the new line is now: Hlt2CharmHadLcpToKmPpKpPi0Turbo.

See LBHLT-416

Purpose

We would like to add a new turbo line for prompt Lambda_c^+ -> p K^+ K^- pi^0 decay, to search for possible pentaquark state in the p phi structure, with phi -> K^+ K^- . We also want to measure the branching fraction of Lambda_c^+ -> p K^+ K^- pi^0 decay.

We also want to use the exisiting PentaToPhiP turbo line for the pentaquark search, but need to change the lower boundary of the mass window.

Details can be found in the talk in trigger meeting: link

The new turbo line

We add a new turbo line called "Hlt2CharmHadLcp2KmKppPi0Turbo", and use the existing "DpDsp2PimPipPipPi0" as template. The rate is tested with 50k Hlt1 accepted events collected in 2017, and 2 events pass the selections, which indicates that the rate is around 5 Hz.

As some of the selections in the exsiting particle filter of proton is tight for this decay, we create a new particle filter called "SharedDetachedLcToHHHPi0Child_p", with requires IPCHI2 > 3, and pT > 200MeV.

The existing PhiToPhiP turbo line

We extend the lower edge of mass window from around 2200MeV to 1900MeV. According to the generator level MC, this could include almost all the phi p candidates from Lambda_c^+ -> p phi pi^0 decays.

The rate of the existing PhiToPhiP turbo line is quite small according to the test with 50K hlt1 accepted events, we also loosen some other selections for it to improve the efficiency. As the Q value for our target decay is small, the p_T variables tend to have a small value. So we:

1. Change the "PT_MIN" for Hlt2CharmHadPentaToPhiPpTurbo line: 2000MeV -> 1000MeV.

2. Change the "ASUMPT_MIN" for Hlt2CharmHadPentaToPhiPpTurbo line: 2200.0MeV -> 1000MeV.