Mass measurements for the T-z =-2 fp-shell nuclei Ti-40, Cr-44, Mn-46, Fe-48, Co-50, and Ni-52

By using isochronous mass spectrometry at the experimental cooler storage ring in Lanzhou, China, masses of short-lived Cr-44, (46)mn and Ni-52 were measured for the first time and the precision of the mass of Ti-40 was improved by a factor of about 2. Relative precisions of delta m/m = (1-2) x 10(-6) have been achieved. Details of the measurements and data analysis are given. The obtained masses are compared with the Atomic-Mass Evaluation 2016 and with theoretical model predictions. The new mass data enable us to extract the higher-order coefficients, d and e, of the quartic form of the isobaric multiplet mass equation for the f p-shell isospin quintets. Unexpectedly large d and e values for the A = 44 quintet are found. By revisiting the previous experimental data on beta-delayed protons from 44 Cr decay, it is suggested that the observed anomaly could be due to the misidentification of the T = 2, J(pi) = 0(+) isobaric analog state in V-44.