Nettsider med emneord «photoproduction»

Heavy nuclei at ultrarelativistic speeds are sources of intense electromagnetic fields, interacting with the other nucleus and leading to photoproduction of charmonium states at very low transverse momenta. A very strong excess of J/psi mesons in this transverse momentum region has been observed by ALICE in peripheral (hadronic) to ultraperipheral Pb-Pb collisions, with and without nuclear overlap.