Study of e+e−→pp¯ in the vicinity of ψ(3770)

Abstract Using 2917 pb − 1 of data accumulated at 3.773 GeV , 44.5 pb − 1 of data accumulated at 3.65 GeV and data accumulated during a ψ ( 3770 ) line-shape scan with the BESIII detector, the reaction e + e − → p p ¯ is studied considering a possible interference between resonant and continuum amplitudes. The cross section of e + e − → ψ ( 3770 ) → p p ¯ , σ ( e + e − → ψ ( 3770 ) → p p ¯ ) , is found to have two solutions, determined to be ( 0.059 − 0.020 + 0.070 ± 0.012 ) pb with the phase angle ϕ = ( 255.8 − 26.6 + 39.0 ± 4.8 ) ° ( 0.166 pb at the 90% confidence level), or σ ( e + e − → ψ ( 3770 ) → p p ¯ ) = ( 2.57 − 0.13 + 0.12 ± 0.12 ) pb with ϕ = ( 266.9 − 6.3 + 6.1 ± 0.9 ) ° both of which agree with a destructive interference. Using the obtained cross section of ψ ( 3770 ) → p p ¯ , the cross section of p p ¯ → ψ ( 3770 ) , which is useful information for the future PANDA experiment, is estimated to be either ( 9.8 − 3.9 + 11.8 ) nb ( 27.5 nb at 90% C.L.) or ( 425.6 − 43.7 + 42.9 ) nb .