Yaxing Tan (BESIII-USTC Group) Study of e+ e- → ϕ(1020)π+ π- Yaxing Tan (BESIII-USTC Group)

Introduction (Cross section Line shape) Cross section line shape of e+ e- → ϕ(1020) π+ π-. Property of Y(2175) → ϕ(1020) f0(980)(π+ π-). PHYSICAL REVIEW D80, 031101(R) (2009) PHYSICAL REVIEW D86, 012008 (2012) Belle BABAR (a) (b) (c) (d) M1 = 2.079±0.013GeV Γ1= 0.192±0.023GeV M2 = 2.180±0.011GeV Γ2 = 0.077±0.018GeV Large error around 2.1GeV: 15%~30%. With R-scan data sets: improve precision (<5~10%). Parameters of Y(2175): Large difference between two results.

Data sets and MC simulation 1.BOSS665p01. 2.R-scan data sets:（in 2015） 3.100K Signal MC at each energy poing. e+ e-→ϕ π+π- 3.08 126.185 2.8 1.008 2.3864 22.549 2.125 108.49 3.02 17.29 2.7 1.034 2.3094 21.089 2.1 12.167 3 15.881 2.6464 33.722 2.2324 11.856 2.05 3.343 2.981 16.071 2.6444 34.003 2.2 13.699 2 10.074 2.95 15.942 2.5 1.098 2.175 10.625 2.9 105.253 2.396 66.869 2.15 2.841

Event selection Good Charged Track: PID: Vertex fit (K+K-π+π-). |Vz| < 10.0 && |Vr|< 1.0 && |cosθ|<0.93; NGood = 4 && NCharge=0; PID: N(π+)=N(π-) = 1; prob_π >prob_K && prob_π >prob_p; N(K+)=N(K-) = 1; prob_K>prob_p && prob_K>prob_π; Vertex fit (K+K-π+π-). 4C kinematic fit (K+K-π+π-). χ24C(K+K- π+π+) < 50;

@2125MeV：L=108.49pb-1 (1) X24C(K+K-π+ π- )<50; (2) ϕ(1020) Fitting : Signal: MC shape Convoluted Gaussian function Background: Argus function NSignal=3419.0±82.0;

ϕ(1020) Fitting

ϕ(1020) Fitting

ϕ(1020) Fitting

Cross section: σ(e+e-→ ϕ(1020) π+π-) Lum.(pb-1) 2 10.074 198.0±24.8 1.0067 17.921 48.9 223.0±27.9 2.05 3.343 85.3±17.3 1.0587 18.463 266.4±54.0 2.1 12.167 381.2±28.3 1.0004 20.315 315.5±23.4 2.125 108.49 3419.0±82.0 1.0046 18.483 346.8±8.3 2.15 2.841 85.3±12.4 1.0568 18.192 320±46.4 2.175 10.625 273.9±23.0 1.0013 22.21 237.2±19.9 2.2 13.699 282.7±22.6 1.1638 19.968 181.3±14.5 2.2324 11.856 176.6±17.5 1.259 18.876 128±12.7 2.3094 21.089 350.8±24.7 1.2477 18.513 147.4±10.4 2.3864 22.549 420.9±26.3 1.122 19.345 176.3±11 2.396 66.869 1351.5±47.1 1.1338 22.681 160.6±5.6 2.4 - 1.1381 23.734 ± 2.5 1.098 12.7±4.5 1.2613 21.812 86±30.5 2.6444 34.003 372.4±24.1 1.236 22.993 79.4±5.1 2.6464 33.722 288.9±22.7 1.2456 22.703 61.4±4.8 2.7 1.034 16.9±5.2 1.6953 17.111 115.3±35.5 2.8 1.008 10.0±3.7 1.4964 19.848 68.5±25.3 2.9 105.253 533.2±29.4 1.3625 21.873 34.7±1.9 2.95 15.942 83.1±11.0 1.2314 22.784 38±5 2.981 16.071 68.0±10.6 1.6956 17.204 29.7±4.6 3 15.881 54.0±9.7 1.6885 17.119 24.1±4.3 3.02 17.29 53.5±9.4 1.7004 16.658 22.4±3.9 3.08 126.185 482.7±26.7 1.7368 15.212 29.6±1.6

Possible intermediate states (R-scan data sets in 2015) @2125MeV

@2125MeV: L=108.49pb-1 (e+e-→ ϕ(1020) π+π- ) ϕ(1020) Signal Region

@2125MeV: L=108.49pb-1 (e+e-→ K*(892)0K- π+ +c.c. )

Thank you

Numbers of NGoodCharge