Limits on the effective quark radius from inclusive ep scattering at HERA

Abstract The high-precision HERAdata allows searches up to TeV scales for beyond the Standard Modelcontributions to electron– quarkscattering. Combined measurements of the inclusive deep inelastic cross sections in neutral and charged currentep scattering corresponding to a luminosity of around 1 fb − 1 have been used in this analysis. A new approach to the beyond the Standard Modelanalysis of the inclusive ep data is presented; simultaneous fits of parton distribution functions together with contributions of “new physics” processes were performed. Results are presented considering a finite radius of quarkswithin the quarkform-factor model. The resulting 95 % C.L. upper limit on the effective quarkradius is 0.43 ⋅ 10 − 16 cm .