Measurement of the Lambda b0 lifetime in Lambda b0-->J/psi Lambda 0 in pp collisions at square root s=1.96 TeV.

Area of Science:

• High Energy Physics
• Particle Physics
• Hadron Spectroscopy

Background:

• The Lambda b0 baryon is a key system for testing Quantum Chromodynamics (QCD) predictions.
• Precise measurements of heavy baryon properties, like lifetime, are crucial for understanding non-perturbative QCD effects.

Purpose of the Study:

• To report a precise measurement of the Lambda b0 baryon lifetime.
• To investigate the exclusive decay channel Lambda b0 --> J/psi Lambda 0.

Main Methods:

• Utilized proton-proton collision data collected by the CDF II detector at the Fermilab Tevatron.
• Analyzed fully reconstructed Lambda b0 --> J/psi Lambda 0 decays.
• Employed a dataset corresponding to an integrated luminosity of 1.0 fb^-1 at a center-of-mass energy of 1.96 TeV.

Main Results:

• Measured the Lambda b0 lifetime, tau(Lambda b0), to be 1.593 ps with combined statistical and systematic uncertainties.
• The measured lifetime is the most precise to date.
• The result is 3.2 standard deviations higher than the current world average.

Conclusions:

• The precise Lambda b0 lifetime measurement provides a new benchmark for theoretical calculations in heavy baryon physics.
• The significant deviation from the world average may indicate new physics phenomena or unresolved theoretical uncertainties.