Quark Confinement and the Hadron Spectrum XI

The nature of a1(1420) and triangle singularity mechanism

Not scheduled

30m

St. Petersburg

Oral Section B: Light Quarks

Speaker

Qiang Zhao (Institute of High Energy Physics, Chinese Academy of Sciences)

Description

We demonstrate that the triangle singularity mechanism would account for the creation of the a1(1420) in the invariant mass spectrum of pi- pi- pi+ in the pi- p scattering observed by the COMPASS Collaboration. The same mechanism also accounts for the eta(1405/1475) puzzle since its interference will lead to significant changes to the lineshapes and peak positions for the same state when it decays into different channels such as K K-bar pi, eta pi pi, and 3pi. The property of its isospin-0 partner f1(1420) is also driven by the same mechanism.