Lattice QCD Evidence that the Lambda(1405) Resonance is an Antikaon-Nucleon Molecule
| Autor: | Hall, Jonathan M. M., Kamleh, Waseem, Leinweber, Derek B., Menadue, Benjamin J., Owen, Benjamin J., Thomas, Anthony W., Young, Ross D. |
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| Rok vydání: | 2014 |
| Předmět: | |
| Zdroj: | Phys. Rev. Lett. 114, 132002 (2015) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevLett.114.132002 |
| Popis: | For almost 50 years the structure of the Lambda(1405) resonance has been a mystery. Even though it contains a heavy strange quark and has odd parity, its mass is lower than any other excited spin-1/2 baryon. Dalitz and co-workers speculated that it might be a molecular state of an antikaon bound to a nucleon. However, a standard quark-model structure is also admissible. Although the intervening years have seen considerable effort, there has been no convincing resolution. Here we present a new lattice QCD simulation showing that the strange magnetic form factor of the Lambda(1405) vanishes, signaling the formation of an antikaon-nucleon molecule. Together with a Hamiltonian effective-field-theory model analysis of the lattice QCD energy levels, this strongly suggests that the structure is dominated by a bound antikaon-nucleon component. This result clarifies that not all states occurring in nature can be described within a simple quark model framework and points to the existence of exotic molecular meson-nucleon bound states. Comment: Manuscript accepted for publication. 4 figures, 5 pages |
| Databáze: | arXiv |
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