Observation of the Decay Ξ_{b}^{-}→pK^{-}K^{-}

Area of Science:

• Particle Physics
• High Energy Physics
• Hadron Spectroscopy

Background:

• The Standard Model of particle physics describes fundamental particles and forces.
• Baryons containing bottom quarks, such as Ξ_{b}^{-} and Ω_{b}^{-}, offer unique opportunities to test the Standard Model.
• Understanding charmless decays of heavy baryons is crucial for probing non-perturbative aspects of Quantum Chromodynamics (QCD).

Purpose of the Study:

• To search for decays of the Ξ_{b}^{-} and Ω_{b}^{-} baryons into charmless final states.
• To measure branching fractions and production fractions of these decays relative to a known channel.
• To investigate the properties of heavy baryon decays and search for new physics phenomena.

Main Methods:

• Analysis of proton-proton collision data collected by the LHCb detector at center-of-mass energies of 7 and 8 TeV.
• Statistical analysis of decay candidates, including background estimation and significance calculation.
• Use of the B^{-}→K^{+}K^{-}K^{-} decay as a normalization channel for relative branching fraction measurements.

Main Results:

• Observation of the Ξ_{b}^{-}→pK^{-}K^{-} decay with a significance of 8.7 standard deviations.
• Evidence for the Ξ_{b}^{-}→pK^{-}π^{-} decay at the 3.4 standard deviation level.
• Measurement of branching fractions and b-hadron production fractions for the observed decays relative to the normalization channel.

Conclusions:

• The study successfully observed a specific decay mode of the Ξ_{b}^{-} baryon and found evidence for another.
• The results provide valuable data for theoretical models describing heavy baryon decays.
• Further studies with larger datasets can improve precision and search for other rare decays.