Total cross section of the process e+e−→π+π−π+π− in the c.m. energy range 980–1380 MeV

R.R Akhmetshin,I.B Logashenko,D.N Grigoriev,N.M Ryskulov,A.A Polunin,B.I Khazin,D.A Gorbachev,N.S Bashtovoy,V.S Okhapkin,A.N Skrinsky,A Baratt,I.G Snopkov,D.V Bondarev,S.G Zverev,A.G Shamov,A.V Bragin,G.V Fedotovitch,J Thompson ,N Root ,N Gabyshev ,V.sh Banzarov ,А С Попов ,Yu M Shatunov ,I.n Nesterenko ,Alexander Valishev ,K Mikhailov ,I A Koop ,B Shwartz ,В Ф Казанин ,F.v Ignatov ,E A Perevedentsev ,А П Лысенко ,P Lukin ,Л.м Барков ,D Epifanov ,A Sibidanov ,A.v Otboev ,A Zaitsev ,S Eidelman ,E P Solodov ,А.а Рубан ,A I Milstein ,V Aulchenko ,A Kuzmin ,S V Karpov ,Yu V Yudin ,A Bondar ,V Sidorov ,P Krokovny ,S I Redin ,А.а Гребенюк

doi:10.1016/j.physletb.2004.05.056

R.R Akhmetshin, I.B Logashenko + Show 49 more

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https://doi.org/10.1016/j.physletb.2004.05.056

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Abstract

The e+e−→π+π−π+π− cross section has been measured using 5.8 pb−1 of integrated luminosity collected with the CMD-2 detector at the VEPP-2M collider. Analysis of the data with a refined efficiency determination and use of both three- and four-track events allowed doubling of a data sample and reduction of systematic errors to 5–7%.

Highlights

Production of four pions in e+e− annihilation is the dominant process contributing to the total hadronic cross section in the c.m. energy range between 1000 and 2000 MeV
For four-track events the remaining background is estimated to be less than 1%
The three-track events used in this analysis allowed a significant increase of the data sample and improvement of the systematic uncertainties

Summary

Introduction

Production of four pions in e+e− annihilation is the dominant process contributing to the total hadronic cross section in the c.m. energy range between 1000 and 2000 MeV. With ω and η decays to π+π−π0), which results in a lower total energy because of a missing π0 To obtain the number of four-pion events from a three-track sample, the distribution shown in Fig. 3(b) was fit with a sum of functions describing a pion peak and background. Some energy-dependent contribution to the total experimental uncertainty is possible below 1100 MeV, but there the systematic error is much smaller than a statistical one

Findings

Discussion

Conclusion