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

FYI: @polye @amato