Speaker
Description
Exotic hadrons beyond the conventional quark model attract much attention because of emerging multiquark states in the meson and baryon sectors. The χc1(3872), also known as X(3872), lies close to DDbar+c.c, has a spin-parity 1++, and decays mainly to DDbarπ0. It also decays to two-body final states involving ccbar mesons (J/ψ(1S)ω, ηc(1S)ω). In analogy to this hidden-charm exotic meson, the hidden-strangeness f1(1420) (JPC=1++) meson can be a flavor partner of the χc1(3872) as it exists below KKbar+c.c. In the baryon sector, hidden-charm pentaquark states, Pc(4380) and Pc(4440) (likely JP=3/2-) lie near the ΛcDbar and ΣcDbar, respectively. These states have been observed only in the J/ψp channel. Similarly, their strange flavor partners Ps(2030) and Ps(2080) near ΛK and ΣK mass thresholds could exist and decay mainly to φp. Enhanced φ photoproduction cross sections near 2.1 GeV may indicate a possible observation of those hidden-strangeness pentaquarks. Unveiling the nature of possible Ps states is fascinating. The LEPS2 solenoidal detector, consisting of a large solenoid magnet and a time projection chamber, has recently completed its first phase of the physics run. I will present the Ps search program with the LEPS2 and J-PARC facilities.
