Precise measurement of Ruds and R between 1.84 and 3.72 GeV at the KEDR detector

Abstract The present work continues a series of the KEDR measurements of the R value that started in 2010 at the VEPP-4M e + e − collider. By combining new data with our previous results in this energy range we measured the values of R uds and R at nine center-of-mass energies between 3.08 and 3.72 GeV. The total accuracy is about or better than 2.6% at most of energy points with a systematic uncertainty of about 1.9%. Together with the previous precise R measurement at KEDR in the energy range 1.84–3.05 GeV, it constitutes the most detailed high-precision R measurement near the charmonium production threshold.