Observation of the charmless purely baryonic decay \mathinner\mathitΛ⁰_b → \mathitΛ p p

2026/05/05 by LHCb collaboration, R. Aaij, M. Abdelfatah +1103 · 2 voices
Physics and Astronomy · #hep-ex

paper · pdf

Abstract

A search for the charmless purely baryonic decay \mathinner\mathitΛ⁰_b → \mathitΛ p p is performed using proton-proton collision data recorded by the LHCb experiment at a centre-of-mass energy of √(s)=13 TeV and corresponding to an integrated luminosity of 6.0 fb^-1. The signal decay is observed with a significance of 5.1 standard deviations. Its branching fraction is measured for the first time, relative to that of the topologically similar decay \mathinner\mathitΛ⁰_b → \mathitΛ K⁺ K^-. Contributions from intermediate charmonium resonances decaying to the p p and K⁺ K^- final states are explicitly excluded with a requirement on the invariant mass of the companion hadron system, m(hh) < 2.85 GeV, where h stands for a proton or a charged kaon. The relative branching fraction is found to be \fracB(\mathinner\mathitΛ⁰_b → \mathitΛ p p)B(\mathinner\mathitΛ⁰_b → \mathitΛ K⁺ K^-) = (5.1 ± 1.3_(stat) ± 0.3_(syst)) × 10^-2 .

Citations

• Purely baryonic weak decays of heavy baryons in a Skyrme model
• The LHCb Stripping Project: Sustainable Legacy Data Processing for High-Energy Physics
• XGBoost: A Scalable Tree Boosting System
• Mass distributions marginalized over per-event errors
• Performance of the LHCb RICH detector at the LHC
• The LHCb Trigger and its Performance in 2011
• Performance of the LHCb Vertex Locator
• Amplitude Analysis of the Decay B0 -> K+pi-pi0
• A Brief Introduction to PYTHIA 8.1
• Geant4 developments and applications
• Decay Chain Fitting with a Kalman Filter
• sPlot: a statistical tool to unfold data distributions
• Sensitivity of searches for new signals and its optimization
• The RooFit toolkit for data modeling
• Review of Particle Physics

Discussions

• Observation of the chΛb⁰→Λpp̅ - The signal decay is observed with a significance of 5.1 standard deviations. arxiv.org/abs/2605.04348 [bsky, 1 points, 0 comments]
• #LHCbpaper: Observation of the charmless purely baryonic decay Λ⁰_b → Λ pp (arXiv:2605.04348) https://arxiv.org/abs/2605.04348 [bsky, 1 points, 0 comments]