Gluon condensation signature in the GeV gamma-ray spectra of pulsars

The accumulation of gluons inside nucleons, i.e., the gluon condensation, may lead to a characteristic broken power-law gamma-ray spectrum in high-energy nucleon collisions. Here we show that observed spectra at least 25 sources second Fermi Large Area Telescope Catalog Gamma-ray Pulsars can be well fitted by such function has only four free parameters. It strongly indicates emission from these pulsars is hadronic origin, but with condensation hadrons. known quark-gluon distribution different bound nucleon. This work exposes nuclear $A$ dependence effect, where refers baryon number. Our study reveals under condition $A\ensuremath{\rightarrow}\ensuremath{\infty}$, which open new window for eavesdropping on structure compact stars subnuclear level.