Measurement of e+e- →φη′ cross sections at center-of-mass energies from 3.508 to 4.951 GeV and search for the decay ψ (3770) →φη′

The cross sections of the e+e-→φη′ process at center-of-mass energies from 3.508 to 4.951 GeV are measured with high precision using 26.1 fb-1 data collected with the BESIII detector operating at the BEPCII storage ring. The cross sections are of the order of a few picobarn and decrease as the center-of-mass energy increases as s-n/2 with n=4.35±0.14. This result is in agreement with the Nambu-Jona-Lasinio model prediction of n=3.5±0.9. In addition, the charmless decay ψ(3770)→φη′ is searched for by fitting the measured cross sections, yet no significant signal is observed. The upper limit of B(ψ(3770)→φη′) at the 90% confidence level is determined to be 2.3×10-5