CLAS physics database search results Measurement E211M2 e2a Steven Dytman 2025 P_p Transparency Stat. error Syst. error GeV/c dimensionless dimensionless dimensionless 0.71 0.61 0.019 0 0.99 0.63 0.017 0 1.3 0.59 0.014 0 1.64 0.6 0.05 0