(a) Direct comparison of TRKR traces on the few-picosecond timescale at A exciton resonance (A exciton res.), trion resonance (X−Sres. and X−Tres.) and B exciton resonance (B exciton res.) energies. (b) Comparison of A and B exciton TRKR traces on the 100 ps timescale with logarithmic amplitude scale. (c) TRKR trace at the B exciton resonance. A bimolecular fit to the data (open circles) is indicated by the solid red line. (d) Schematic illustration of A and B exciton configurations for WS2 in the K+ valley. The yellow and orange arrows indicate the conduction-band splin-flip and radiative recombination processes leading to the decay of the A exciton Kerr signal.