Measurement of R uds and R between 3.12 and 3.72 GeV at the KEDR detector

Abstract Using the KEDR detector at the VEPP-4M e + e − collider, we have measured the values of R uds and R at seven points of the center-of-mass energy between 3.12 and 3.72 GeV. The total achieved accuracy is about or better than 3.3 % at most of energy points with a systematic uncertainty of about 2.1 % . At the moment it is the most accurate measurement of R ( s ) in this energy range.