EPP Theory Seminar: Sebastian Neubert - The Charmonium-like Exotic Meson χc1(3872) at LHCb
The discovery of a narrow charmonium-like state above the open charm threshold in 2001 has triggered a renaissance for hadron spectroscopy. Despite almost two decades of careful studies the nature of this meson, called χc1(3872) is still under debate. LHCb has determined its spin-parity quantum numbers to be JPC=1++, excluding the assignment of the closest charmonium state to this resonance. Among its many peculiar properties the mass, right at the DD* threshold stands out. Recently the LHCb collaboration has released two new measurements of this parameter and for the first time has measured a value for the width. Using a Flatte-inspired model the analytic structure of the amplitude in the vicinity of the DD* threshold has been investigated. The results are compatible with the interpretation of the χc1(3872) having a dominantly molecular DD* nature.