Cosmic Colliders in Binary Blazars Probing Ultra-High-Energy Particle Physics

Abstract

While terrestrial colliders and fixed-target cosmic-ray interactions are bounded at center-of-mass (CM) energies $\sqrt{s}\lesssim \mathcal{O}(10^5)\text{GeV}$, we demonstrate that bound sub-parsec binary blazars form broad-band, beam-beam hadronic ``Cosmic Colliders'', overcoming such limitation. Driven by modest jet misalignments (${\theta }_{\mathrm{mis}}\sim 1^{\circ }-6^{\circ }$), co-streaming proton beams collide at CM energies reaching $\sqrt{s}\sim 10^{10}\text{GeV}$ - six orders of magnitude above the Large Hadron Collider. Operating in a strictly optically thin regime (${\tau }_{pp}\ll 1$), the system performs a continuous CM energy scan, probing asymptotic QCD scaling, gluon saturation, and Froissart unitarity, while opening a possible high-sensitivity window into physics beyond the Standard Model. Secondary PeV-EeV neutrinos and sub-TeV $\gamma$-rays fall directly within reach of current and planned observatories such as LHAASO, CTAO, IceCube, and GRAND, establishing binary blazars as laboratories for physics at the ultimate energy limit.

arXiv comment32 pages, 15 figures