Physics of High-Mass Dimuon Production at the 50-GeV Proton Synchrotron

摘要

We discuss the physics interest and the experimental feasibility fordetecting high-mass dimuon pairs using the planned 50-GeV Proton Synchrotron(PS) at the KEK/JHF and JAERI/NSP joint accelerator project. The Drell-Yanmeasurement of $p+d$ versus $p+p$ at 50 GeV will provide unique information onthe flavor asymmetry of proton's up and down sea-quark distributions in thelarge-$x$ region. A study of the nuclear dependences of Drell-Yan crosssections can reveal the modification of antiquark distributions in nuclei.Furthermore, the effect of energy loss for fast partons traversing nuclearmedium could also be sensitively measured. If polarized proton beam becomesavailable at the 50-GeV PS, unique information on the sea-quark polarizationcould be obtained. Study of heavy quarkonium production at the 50-GeV PS canset important constraints on the mechanism of vector meson productions. Using aprototype dimuon spectrometer, we have simulated the sensitivities for avariety of measurements.