Model-Independent Evidence for J/ψ p Contributions to Λ0b → J/ψ p K− Decays

The data sample of Λ0b → J/ψ p K− decays acquired with the LHCb detector from 7 and 8 TeV pp collisions, corresponding to an integrated luminosity of 3 fb^−1, is inspected for the presence of J/ψ p or J/ψ K− contributions with minimal assumptions about K− p contributions. It is demonstrated at more than nine standard deviations that Λ0b → J/ψ p K− decays cannot be described with K− p contributions alone, and that J/ψ p contributions play a dominant role in this incompatibility. These model-independent results support the previously obtained model-dependent evidence for Pc+ → J/ψ p charmonium-pentaquark states in the same data sample.