Study of K+ K- π0 in J/y →h’ K+ K- π0 Based on Boss6.5.5 225M J/y data 2019/2/18
Data sample Boss 6.5.5 J/y experimental data MC sample 225M J/y inclusive MC sample 500K signal MC sample J/y →h’ h1(1380) , h1(1380) → K*+K-+c.c , h ’ → π+ π- h 500K MC for each exclusive background channel 2019/2/18
Selection criteria(I) Charged tracks |Rxy|<1cm, |Z0|<10cm, |Cos θ |<0.93; nGood ≥ 4; Neutral tracks Ebarrel > 25MeV ; Eendcap > 50MeV; 0 ≤ time ≤ 14; Nγ ≥ 4; PID (dE/dx and TOF) Prob(K) > Prob(P) , Prob(K) > Prob(π) Prob(π) > Prob(P) , Prob(π) > Prob(K) Nk+ = Nk-=1, Nπ+ = Nπ-=1 2019/2/18
Selection criteria(II) Vertex for K+K- π+π-: Successful 4C Kinematic fit Loop γ γ γ γ and combination with Minimum χ24c(K+K- π+π- γ γ γ γ ) is chosen. h and π0 selection For two pairs of photons , select combination with minimum 2019/2/18
4C Kinematic fit χ24c < 80 Scaled with event number 2019/2/18
Further selection of h and π0 For π0 candidate |Mγγ - Mπ0 | < 0.02 GeV/c2 For h candidate |Mγγ - Mh | < 0.025 GeV/c2 2019/2/18
h’ selection h ’ For h ’ candidate |Mπ+π-h – Mh’ | < 0.02 GeV/c2 2019/2/18
Distribution of MK+K-π0 h1(1380) 2019/2/18
KK_KKπ0 (2D) 2019/2/18
K* signal
Inclusive/Data comparison
After K*selection 2019/2/18
Background study Sideband region to study non-h’ or non-π0 background Inclusive MC/Exclusive MC to study background 2019/2/18
non-h’ or non-π0 background Data Scale factor need MC 2019/2/18
Branch ratio estimate J/y → h’ K*- K+ :MC 500K ’ selection : |Mπ+π-h – Mh’ | < 0.02 GeV/c2 Veto KKPi0 resonance: 1.55<M K+K- π0 <1.8 efficiency = 0.028504 Br(J/y → h’ K*- K+ )= (211)/(0.028504)/225*106 =3.29×10-5 FCN=-2417.85 FROM MINOS STATUS=SUCCESSFUL 772 CALLS 1045 TOTAL EDM=0.000128 STRATEGY= 1 ERROR MATRIX ACCURATE EXT PARAMETER PARABOLIC MINOS ERRORS
Branch ratio estimate J/y → h’ K- K*+ :MC 500K ’ selection : |Mπ+π-h – Mh’ | < 0.02 GeV/c2 Veto KKPi0 resonance: 1.55<M K+K- π0 <1.8 efficiency = 0.029154 Br(J/y → h’ K*+ K- )= (187)/(0.029154)/225*106 =2.85×10-5 MIGRAD FAILS WITH STRATEGY=0. WILL TRY WITH STRATEGY=1. FCN=-2386.39 FROM MINOS STATUS=SUCCESSFUL 1128 CALLS 1553 TOTAL EDM=0.00014994 STRATEGY= 1 ERROR MATRIX ACCURATE EXT PARAMETER PARABOLIC MINOS ERRORS
Branch ratio estimate J/y → h’ K- K+ π0 :MC 500K 2019/2/18
Comparison of data and MC 2019/2/18
Comparison of data and MC 2019/2/18
2019/2/18
Possible background channels Veto h1(1380)：MKKπ0 >1.55 Inclusive topology Possible background channels N inc J/y →h’ K*+ K- → π+π-h K+π0 K- → π+π-K+K- γγγγ (phase space) (124) J/y →h’ K*- K+ → π+π-h K-π0 K+ → π+π-K+K- γγγγ (phase space) (114) J/y →h’ K*-(1410)K+ → π+π-h K-π0 K+ → π+π-K+K- γγγγ (4) J/y →h’ K*+(1410)K- → π+π-h K-π0 K+ → π+π-K+K- γγγγ (4) J/y → anti-K*0 ρ- K*+ → K+π- K+π0 π-π0 → π+π-K+K- γγγγ (h’ sideband) (4) J/y → anti-K*0 ρ+ K*- → K+π- K+π0 π-π0 → π+π-K+K- γγγγ (h’ sideband) (3) J/y →h’ f’2(1525) γ → π+π-h K+K- γ → π+π-K+K- γγγ (π0 sideband) (2) J/y →h K1(1270)+ K*- → γγ π- K+π+ π0 K- → π+π-K+K- γγγγ (h’ sideband) (2) J/y →a0(980) K1+(1270) K- → hπ0 K+ρ0 K- → π+π-K+K- γγγγ (h’ sideband) (2) J/y →a0(980) K1-(1270) K+ → hπ0 K-ρ0 K+ → π+π-K+K- γγγγ (h’ sideband) (2) J/y →h K2*+(1430) K- → γγ π+π-K*+ K- → γγ π+π-K+ π0 K- → π+π-K+K- γγγγ (h’ sideband) (2) J/y →φ h h → K-K+ π0π+π-γγ → π+π-K+K- γγγγ (h’ sideband) (2)
Veto h1(1380)：MKKπ0 >1.55 Inclusive topology J/y →h’ K- K+ → π+π-h K- K+ → π+π-K+K- γγγγ (phase space) The topology analysis didn’t list this possible background channel. The difference between inclusive MC and data may du to the smaller Branch ratio inputted in MC . We’d better use data to estimated the Branching ratio included.
2019/2/18
Intermediate states : K*+and K*- 2019/2/18
2019/2/18
J/y →h’ K+ K- π0 h’ → γ π+ π- Based on Boss6.5.5 2019/2/18
4C Kinematic fit 2019/2/18
Further selection of π0 For π0 candidate |Mγγ - Mπ0 | < 0.02 GeV/c2 2019/2/18
h’ selection For h ’ candidate |Mπ+π-h – Mh’ | < 0.02 GeV/c2 h’ 2019/2/18
Distribution of MK+K-π0 2019/2/18
K* signal 2019/2/18
After K* selection 2019/2/18