Speaker
Dr
Lei Feng
Description
The data collected by ATIC, CREAM and PAMELA all display remarkable
cosmic-ray-nuclei spectrum hardening above the magnetic rigidity $\sim$
240 GV. One natural speculation is that the primary electron spectrum
also gets hardened at $\sim 240$ GeV, which can partly account for the
electron/positron total spectrum excess discovered by ATIC, HESS and
Fermi-LAT. The subsequent positron-to-electron ratio may get flattened
or even decreased, depending on the degree of the primary electron
spectrum hardening. Such modification is detectable for AMS-02, a
mission dedicated to measure the high energy cosmic ray spectra with
unprecedented accuracy. The spectrum hardening of both primary-electrons
and nuclei at $\sim 240$ GV, if confirmed by AMS-02 in the future, is
likely attributed to a "nearby" supernova-remnant-like source with a
lifetime $\lesssim 10^{13}$ s. Possible dark matter origin of the
positron excess revealed by PAMELA is also investigated.
Primary author
Dr
Lei Feng
