Ponente
Descripción
Precision measurements by the Alpha Magnetic Spectrometer (AMS) on the International Space Station of the deuteron ($D$) flux are presented. The measurements are based on 21 million $D$ nuclei in the rigidity range from 1.9 to 21 GV collected from May 2011 to April 2021. We observe that over the entire rigidity range the $D$ flux exhibits nearly identical time variations with the $p$, $^3$He , and $^4$He fluxes. Above 4.5 GV, the $D$/$^4$He flux ratio is time independent and its rigidity dependence is well described by a single power law $\propto R^\Delta$ with $\Delta_{D/{}^4\text{He}} =-0.108 \pm 0.005$. This is in contrast with the $^3$He/$^4$He flux ratio for which we find $\Delta_{{}^3\text{He}/{}^4\text{He}} =-0.289 \pm 0.003$. Above $\sim$13 GV we find a nearly identical rigidity dependence of the $D$ and $p$ fluxes with a $D/p$ flux ratio of $0.027 \pm 0.001$. These unexpected observations indicate that cosmic deuterons have a sizable primarylike component. With a method independent of cosmic ray propagation, we obtain the primary component of the $D$ flux equal to $9.4 \pm 0.5 \%$ of the $^4$He flux and the secondary component of the $D$ flux equal to $58 \pm 5 \%$ of the $^3\text{He}$ flux.
