Measurement of the coupling constant αs of the strong interaction from jet rates in the deep inelastic ep scattering at HERA

The coupling constant αs of the strong interaction was measured in the ZEUS experiment at the HERA storage ring. For this in a kinematic range of 1200.1 the (2+1) jet rate from deep inelastic ep scattering experiments was determined. The measured value of αs with the JADE algorithm is: αs(MZ0)=0.117±0.005(stat)+0.004-0.005(systexp)±0. 0 07(systtheory). The result of the αs determination with the KT algorithm and a constant reference mass in the same kinematical range is: αs(MZ0)=0.120±0.004(stat). If Q2 is used as reference mass, for αs results: αs(MZ0)=0.118±0.006(stat)