A Common Antimatter Response in AMS-02 Positrons and Antiprotons

Abstract

AMS-02 has reported a high-rigidity regularity that is difficult to interpret as a positron-only fact: above about $60\mathrm{GV}$, antiprotons, protons, and positrons have nearly identical rigidity dependence, whereas electrons do not. I argue that this pattern suggests a common antimatter response. The organizing principle is a no-extra-source one: antiparticles retain their production history, but their post-production retarded exposure can be reduced relative to an ordinary retarded response. For positrons this is reduced accumulated radiative exposure rather than an added positron-only source. For antiprotons, whose production is hadronic and secondary, the production kernel is kept fixed; the corresponding effect is a reduction of the second, post-production residence softening rather than a new antiproton source. In a power-law response language, the required hardening ${\Delta }_{\bar{p}}$ must compensate the ordinary secondary softening ${\delta }_{\mathrm{eff}}$, giving ${\Delta }_{\bar{p}}\simeq {\delta }_{\mathrm{eff}}$. The resulting test is direct: conventional explanations must reproduce the joint high-rigidity slope geometry of $p$, $\bar{p}$, $e^{+}$, and $e^{-}$, not only the one-dimensional $\bar{p}/p$ ratio.