Using the data sample of 980 fb-1 collected with the Belle detector operating at the KEKB asymmetric-energy e+e- collider, we present the results of an investigation of the Λπ+ and Λπ- invariant mass distributions looking for substructure in the decay Λc+→Λπ+π+π-. We find a significant signal in each mass distribution. When interpreted as resonances, we find for the Λπ+ [Λπ-] combination a mass of 1434.3±0.6(stat)±0.9(syst) MeV/c2 [1438.5±0.9(stat)±2.5(syst) MeV/c^2], an intrinsic width of 11.5±2.8(stat)±5.3(syst) MeV/c2 [33.0±7.5(stat)±23.6(syst) MeV/c2] with a significance of 7.5σ (6.2σ). As these two signals are very close to the KN threshold, we also investigate the possibility of a KN cusp, and find that we cannot discriminate between these two interpretations due to the limited size of the data sample.
First Observation of Λπ+ and Λπ- Signals near the KN(I=1) Mass Threshold in Λc+→Λπ+π+π- Decay
Tenchini, F;
2023-01-01
Abstract
Using the data sample of 980 fb-1 collected with the Belle detector operating at the KEKB asymmetric-energy e+e- collider, we present the results of an investigation of the Λπ+ and Λπ- invariant mass distributions looking for substructure in the decay Λc+→Λπ+π+π-. We find a significant signal in each mass distribution. When interpreted as resonances, we find for the Λπ+ [Λπ-] combination a mass of 1434.3±0.6(stat)±0.9(syst) MeV/c2 [1438.5±0.9(stat)±2.5(syst) MeV/c^2], an intrinsic width of 11.5±2.8(stat)±5.3(syst) MeV/c2 [33.0±7.5(stat)±23.6(syst) MeV/c2] with a significance of 7.5σ (6.2σ). As these two signals are very close to the KN threshold, we also investigate the possibility of a KN cusp, and find that we cannot discriminate between these two interpretations due to the limited size of the data sample.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
