In Fig. 3b of this Letter, the y axis numbering should be identical to that of Fig. 3a, and start at 2 MeV and go up to 25 MeV. Instead, the numbering was inadvertently shifted upwards, which made the data shown in Fig. 3b appear to have higher values by 2 MeV with respect to their actual ones. Figure 3 has been corrected in the HTML and PDF of the original manuscript.