Update `dhhh` lines: joint lines with same final state
This MR:
- Removes BPVFDCHI2 cuts
- Combines lines for D+ and Ds+ decays into the same final states, keeping the loosest selection between the two previous lines and a joint mass window
This reduces by half the number of D(s)+ -> 3h lines, and the total rate is also reduced to (24.9 +- 0.2) kHz.
More details bellow:
Selection
Particle filter
| Variable | Cut |
|---|---|
| PT | > 250 MeV/c |
| P | > 2 GeV/c |
| TRCHI2PDOF | < 99. |
| MIPCHI2 | > 4. |
| PIDK (pions) | < 5 [<1 D(s)PPP, D(s)PPK] |
| PIDK (kaons) | > 5 |
2-body combination
| Variable | Cut |
|---|---|
| DOCA(1,2) | < 0.1 mm |
3-body combination
| Variable | Cut |
|---|---|
| Mass | > 1779 MeV/c^2
|
| Mass | < 2059 MeV/c^2
|
| PTsum | > 3 GeV/c (> 3.2 GeV/c for D(s)PPP) |
| PT (2 of 3) | > 400 MeV/c |
| PT (1 of 3) | > 1 GeV/c |
| MIPCHI2 (2 of 3) | > 10. (> 4. for D(s)KKK) |
| MIPCHI2 (1 of 3) | > 50. (> 10. for D(s)KKK) |
| DOCA(1,3) | < 0.1 mm |
| DOCA(2,3) | < 0.1 mm |
Composite (vertex)
| Variable | Cut |
|---|---|
| Mass | > 1789 MeV/c^2
|
| Mass | < 2049 MeV/c^2
|
| VCHI2PDOF | < 9. |
| BPVLTIME | > 0.2 ps |
| *BPVIPCHI2 | < 20 |
| *acos(BPVDIRA) | < 14.1 mrad |
| PT | > 2.5 GeV/c |
*we have lines without BPVIPCHI2 and BPVDIRA cuts with a prescale of 0.05 to study the impact over secondary contamination
Rates
Rates computed with ~402k events from UpgradeHLT1FilteredMinbias sample
Prompt Lines
| Lines | Rate (kHz) | Rate (kHz) w/o IPCHI2, DIRA (5% prescale) |
|---|---|---|
D_{(s)}^{+} \rightarrow K^-K^+K^+ |
0.30 \pm 0.03 |
0.10 \pm 0.02 |
D_{(s)}^{+} \rightarrow K^-K^+\pi^+ |
3.7 \pm 0.1 |
0.53 \pm 0.04 |
D_{(s)}^{+} \rightarrow K^-\pi^+\pi^+ |
11.3 \pm 0.2 |
0.93 \pm 0.05 |
D_{(s)}^{+} \rightarrow \pi^-K^+K^+ |
0.65 \pm 0.04 |
0.18 \pm 0.02 |
D_{(s)}^{+} \rightarrow \pi^-\pi^+K^+ |
2.84 \pm 0.08 |
0.70 \pm 0.04 |
D_{(s)}^{+} \rightarrow \pi^-\pi^+\pi^+ |
2.52 \pm 0.08 |
0.57 \pm 0.04 |
| Total | 21.3 \pm 0.2 |
3.01 \pm 0.09 |
Secondary decays Lines
| Lines | Rate (kHz) |
|---|---|
B^0 \rightarrow D^{-}(\rightarrow K^-K^+\pi^-)\pi^+ |
0.05 \pm 0.01 |
B^0 \rightarrow D^{-}(\rightarrow \pi^-\pi^+\pi^-)\pi^+ |
0.05 \pm 0.01 |
B_{s}^0 \rightarrow D_{s}^{-}(\rightarrow K^-K^+\pi^-)\pi^+ |
0.05 \pm 0.01 |
B_{s}^0 \rightarrow D_{s}^{-}(\rightarrow \pi^-\pi^+\pi^-)\pi^+ |
0.05 \pm 0.01 |
| Total | 0.20 \pm 0.02 |
Total d_to_hhh rate: (24.5 \pm 0.2) kHz
Mass histograms
Monitoring histograms produced with ~402k events from UpgradeHLT1FilteredMinbias sample
Edited by Felipe Luan Souza De Almeida