  The kaonic 3He and 4He X-rays emitted in the 3d-2p transitions were measured
in the SIDDHARTA experiment. The widths of the kaonic 3He and 4He 2p states
were determined to be Gamma_2p(3He) = 6 \pm 6 (stat.) \pm 7 (syst.) eV, and
Gamma_2p(4He) = 14 \pm 8 (stat.) \pm 5 (syst.) eV, respectively. Both results
are consistent with the theoretical predictions. The width of kaonic 4He is
much smaller than the value of 55 \pm 34 eV determined by the experiments
performed in the 70's and 80's, while the width of kaonic 3He was determined
for the first time.
