Kaon-nucleon scattering from chiral Lagrangians

C.-H. Lee , J. Hong , D.-P. Min , M. Rho (1)

1 SPhT - Service de Physique Théorique

The $ s $-wave $ K^{\pm} N $ scattering amplitude is computed up to one-loop order corresponding to next-to-next-to-leading order (or $ {\rm N}^ {\rm 2} {\rm LO} $ in short) with a heavy-baryon effective chiral Lagrangian. Constraining the low-energy constants by on-shell scattering lengths, we obtain contributions of each chiral order up to $ {\rm N}^ {\rm 2} {\rm LO} $ and find that the chiral corrections are \lq\lq natural\rq\rq\ in the sense of viable effective field theories. We have also calculated off-shell $ s $-wave $ K^-N $ scattering amplitudes relevant to kaonic atoms and $ K^- $ condensation in \lq\lq nuclear star\rq\rq\ matter including the effect of $ \Lambda( 1405). $ The $ K^-p $ amplitude is found to be quite sensitive to the intermediate $ \Lambda( 1405) $ contribution, while the $ K^-n $ amplitude varies smoothly with the C.M. energy. The crossing-even one-loop corrections are found to play an important role in determining the higher-order chiral corrections.

Domaines: Physique Générale [physics.gen-ph]; Physique des Hautes Energies - Phénoménologie [hep-ph]

C.-H. Lee, J. Hong, D.-P. Min, M. Rho. Kaon-nucleon scattering from chiral Lagrangians. Physics Letters B, 1994, 326, pp.14-20. ⟨hal-00169033⟩