Sudakov suppression and the proton form factor

The proton Dirac form factor is calculated using the modified factorization formula proposed by Li and Sterman, which takes into account Sudakov suppression of elastic scattering for soft gluon exchange. The results for ${\Lambda }_{\mathrm{QCD}}=0.1-0.2\mathrm{}$ GeV are in good agreement with experimental data above the energy scale of 3 GeV. The calculation involves no phenomenological parameters such as a gluon mass and the conclusions are insensitive to different models of wave functions.