Study ofe+e−→ΛΛ¯,Λ

Abstract

We study the e + e − → ΛΛγ, ΛΣ 0 γ, Σ 0 Σ 0 γ processes using 230 fb −1 of integrated luminosity collected by the BABAR detector at e + e − center-of-mass energy of 10.58 GeV. From the analysis of the baryon-antibaryon mass spectra the cross sections for e + e − → ΛΛ, ΛΣ 0 , Σ 0 Σ 0 are measured in the dibaryon mass range from threshold up to 3 GeV/c 2 . The ratio of electric and magnetic form factors, |GE/GM |, is measured for e + e − → ΛΛ, and limits on the relative phase between Λ form factors are obtained. We also measure the J/ψ → ΛΛ, Σ 0 Σ 0 and ψ(2S) → ΛΛ branching fractions.

Study of J/ψ and ψ(3686) decay to ΛAblikim1, Ачасов2, Ahmed3 et al. 2017Phys. Rev. DSelf Cite

“…The decay branching fractions and α values are measured, and the results are summarized in Table VI. The branching fractions for J=ψ decays are in good agreement with the results of BESII [10] and BABAR [12] experiments, and those for ψð3686Þ decays are in agreement with the results of CLEO [9], BESII [11] and Dobbs et al [13] with a maximum of 2 times the standard deviations. The earlier experimental results [5][6][7][8] have significant differences with those of this analysis.…”

Observation of a cross-section enhancement near mass threshold in e+e−→ΛΛAblikim1, Ачасов2, Ahmed3 et al. 2018Phys. Rev. DSelf Cite800580View full textAdd to dashboardCite

“…The observed threshold enhancement implies a more complicated underlying physics scenario. The Born cross sections of process e þ e − → ΛΛ are also measured at ffiffi ffi s p ¼ 2.400, 2.800 and 3.080 GeV, and are in good agreement with BABAR and DM2's results [14,15], but with improved precision. Furthermore, the effective electromagnetic FFs of Λ are presented at each c.m.…”

“…Unusual behavior in the near-threshold region has been observed for both e þ e − → pp and e þ e − → nn cross sections [8,10,13]. Compared with neutrons, the production cross section and FFs of hyperons are however hardly explored [14][15][16]. The BABAR experiment measured the hyperon final states of ΛΛ [15] with significantly larger uncertainties compared to the proton case.…”

“…Compared with neutrons, the production cross section and FFs of hyperons are however hardly explored [14][15][16]. The BABAR experiment measured the hyperon final states of ΛΛ [15] with significantly larger uncertainties compared to the proton case. The cross section of e þ e − → ΛΛ in a wide c.m.…”

Narrow resonances studies with the radiative return method

“…Exclusive reactions, specifically two-body final states like þ À [3,4], p " p [5], or à " à [6] and three- [7,8] and four-meson final states [9,10] have been explored. An important ingredient in these analyses was and is the simulation of all these reactions through a Monte Carlo generator.…”