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 $Δ_{\bar p}$ must compensate the ordinary secondary softening $δ_{\rm eff}$, giving $Δ_{\bar p}\simeqδ_{\rm eff}$. 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.