Low energy antikaon-nucleon/nuclei interaction studies by AMADEUS

K Piscicchia,M Bazzi,L De Paolis,A M Bragadireanu,F Ghio,P Levi Sandri,C Guaraldo,G Belloti,M Iwasaki,S Wycech,M Iliescu,M Silarski,R S Hayano,C Curceanu,R Del Grande,E Widmann,P Moskal,M Skurzok,M Cargnelli,D Bosnar,F Sirghi,S Okada,A Spallone,L Fabbietti,J Zmeskal,O Vázquez Doce ,J Márton ,M Miliucci ,D Sirghi ,Arslan Dawood Butt ,À Ramos ,C Fiorini,A Scordo

doi:10.1063/1.5118389

Abstract

The AMADEUS experiment at the DAΦNE collider of LNF-INFN deals with the investigation of the at-rest, or low-momentum, K− interactions in light nuclear targets, with the aim to constrain the low energy QCD models in the strangeness sector. The 0 step of the experiment consisted in the reanalysis of the 2004/2005 KLOE data, exploiting K− absorptions in H, 4He, 9Be and 12C, leading to the first invariant mass spectroscopic study with very low momentum (about 100 MeV) in-flight K− captures. With AMADEUS step 1 a dedicated pure Carbon target was implemented in the central region of the KLOE detector, providing a high statistic sample of pure at-rest K− nuclear interaction. The first measurement of the non-resonant transition amplitude |AK− n→Λπ− | at s=33 MeV below the K̄N threshold is presented, in relation with the Λ(1405) properties studies. The analysis procedure adopted in the search for K− multi-nucleon absorption cross sections and Branching Ratios will be also described.

Highlights

The absorption of low momentum K− mesons, produced by the DAΦNE [1] collider, on He and C nuclear targets is investigated, with the aim to get information on the resonant and non-resonant transition amplitudesThe 13th International Conference on Hypernuclear and Strange Particle Physics AIP Conf
According to the chiral unitary model [2, 3, 4] the Λ(1405) can be interpreted as a molecular meson-baryon state, emerging from the interference of two poles, a lower mass pole which is mainly coupled to the Σπ channel and a high mass pole, coupled to the KN production channel, located around 1420 MeV. For this reason the shape of the measured (Σπ)0 invariant mass distribution is expected to change depending on the decay channel, due to the isospin interference term and on the production channel
The analysis procedure adopted in the search for K− multi-nucleon absorption cross sections and Branching Ratios (BR) will be described

Summary

Introduction

The absorption of low momentum K− mesons (pK ∼ 127 MeV/c), produced by the DAΦNE [1] collider, on He and C nuclear targets is investigated, with the aim to get information on the resonant and non-resonant transition amplitudesThe 13th International Conference on Hypernuclear and Strange Particle Physics AIP Conf. The absorption of low momentum K− mesons (pK ∼ 127 MeV/c), produced by the DAΦNE [1] collider, on He and C nuclear targets is investigated, with the aim to get information on the resonant and non-resonant transition amplitudes

Results

Conclusion