VEX: Photoproduction of Excited Vector Mesons

Elastic photoproduction should be ideal for studying the excitations (V ) of the vector mesons. Although there is general agreement about the existence of the corresponding excited isovector-vector mesons (ρ(1450) and ρ(1700)), the excited isoscalar-vector mesons (ω(1420) and ω(1650)) and the excited isoscalar-vector with hidden strangeness (φ(1680)), measurements of the masses, widths and decay modes are inconsistent. Much of the information in hand comes from a experiments studying e+e− collisions with a only a few results from experiments studying hadroor photo-production. We propose to search for and measure the masses, widths and decay modes of these excited vector states in the reaction γp → V p. The proposed experiment (vex) will use a bremsstrahlung photon beam produced with 6 GeV electrons. The detector consists of a 3-cm LH2 target, charged particle tracking and electromagnetic calorimetry around and downstream of the target and a time-of-flight system. The experiment will focus on final states containing a recoil proton and some combination of mesons leading to of neutral energy in the calorimeter and/or two additional charged particles.