Evidence for Exotic Hadron Contributions to Λ_{b}^{0}→J/ψpπ^{-} Decays

Area of Science:

• High Energy Physics
• Particle Physics
• Quantum Chromodynamics

Background:

• The study of exotic hadrons provides insights into the strong force.
• Previous observations of exotic states like Pc(4380)+, Pc(4450)+, and Zc(4200)- have been reported in different decay channels.

Purpose of the Study:

• To perform a full amplitude analysis of Lambda_b0 -> J/psi p pi- decays.
• To investigate the presence and significance of exotic states in this decay channel.
• To compare the results with previous findings and theoretical expectations.

Main Methods:

• Utilized a large dataset from LHCb detector at 7 and 8 TeV pp collisions.
• Performed a full amplitude analysis incorporating nucleon excitations and exotic states.
• Assessed the statistical significance of the included exotic states.

Main Results:

• A significantly improved description of the data was achieved by including exotic states.
• The inclusion of Pc(4380)+, Pc(4450)+, and Zc(4200)- states provided the best fit.
• The data support a model with all three exotic states with a significance > 3 standard deviations.
• Production rates of Pc(4380)+ and Pc(4450)+ are consistent with previous observations, considering Cabibbo suppression.

Conclusions:

• The analysis provides strong evidence for the existence of three exotic states in the Lambda_b0 -> J/psi p pi- decay.
• These findings contribute to the understanding of the complex spectrum of exotic hadrons.
• The results highlight the importance of amplitude analysis in uncovering subtle phenomena in particle decays.