First Observation of the Charmless Baryonic Decay B^{+}→Λ[over ¯]pp[over ¯]p

Area of Science:

• Particle Physics
• High Energy Physics
• Experimental Physics

Background:

• The study focuses on charmless baryonic decays of the B+ meson.
• Understanding these decays is crucial for testing the Standard Model of particle physics.

Purpose of the Study:

• To search for and characterize the charmless baryonic decay B+ -> Lambda-bar p p-bar p.
• To measure its branching fraction and CP asymmetry for the first time.

Main Methods:

• Analysis of proton-proton collision data from the LHCb experiment.
• Measurement of the branching fraction relative to a normalization channel (B+ -> J/psi K+).

Main Results:

• The branching fraction B(B+ -> Lambda-bar p p-bar p) was measured to be (2.15 ± 0.35 ± 0.12 ± 0.28) x 10^-7.
• The CP asymmetry was measured to be A_CP = (5.4 ± 15.6 ± 2.4)%.
• Invariant mass distributions show enhancements at kinematic thresholds.

Conclusions:

• This is the first measurement of the branching fraction for this decay.
• The observed features in the mass distributions warrant further theoretical investigation.