Speaker
Prof.
Derek Leinweber
(University of Adelaide)
Description
For almost 50 years the structure of the Lambda(1405) resonance has been a mystery for particle physicists. Even though it contains a heavy strange quark and has odd parity its mass is lower than any other excited spin-1/2 baryon. Before the existence of quarks was confirmed, Dalitz and co-workers speculated that it might be a molecular state of an anti-kaon bound to a nucleon. Although the intervening years have seen considerable effort, there has been no convincing resolution. Here we demonstrate that a new lattice QCD simulation showing that its strange magnetic form factor vanishes, together with a comprehensive Hamiltonian effective field theory analysis of the lattice QCD energy levels, unambiguously establishes that the structure is dominated by a bound anti-kaon--nucleon component. This result clarifies that not all states occuring in Nature can be described within a simple quark model framework and establishes the existence of exotic molecular meson-nucleon bound states
Primary author
Prof.
Derek Leinweber
(University of Adelaide)
Co-authors
Prof.
Anthony Thomas
(University of Adelaide)
Mr
Ben Menadue
(University of Adelaide)
Mr
Benjamin Owen
(University of Adelaide)
Dr
Jonathan Hall
(University of Adelaide)
Dr
Ross Young
(University of Adelaide)
Dr
Waseem Kamleh
(University of Adelaide)
