New extraction of αs(MZ) from proton DIS data Original Research Article

An exploratory study for a new determination of the strong coupling constant αs(MZ) from existing world data on the proton structure function F2p in the Q2-range from ≈5 to ≈120 (GeV/c)2 is presented. The main features of our approach are: (1) the use of low-order Nachtmann moments evaluated with a direct contribution from data larger than 70% of the total; (2) the inclusion of high-order perturbative effects through the soft gluon resummation technique; (3) a direct control over higher-twist effects; and (4) the independence from any specific choice of the x-shape of the input parton distributions. At next-to-leading order we get αs(MZ)=0.1209±0.0010(stat.)±0.0015(syst.) with a significant dependence upon the order of the moment used. Including soft gluon effects we obtain αs(MZ)=0.1188±0.0010(stat.)±0.0014(syst.) with a remarkable better stability against the order of the moment. Our findings are compared with recent DIS determinations of αs(MZ) and directions for future improvements are discussed.