Measurement of the Lambda_b^0 lifetime in the exclusive decay Lambda_b^0 -> J/psi Lambda^0 in ppbar collisions at sqrt(s)=1.96 TeV

TL;DR

This paper reports a precise measurement of the Lambda_b^0 baryon lifetime and its ratio to the B^0 meson lifetime using proton-antiproton collision data at 1.96 TeV, providing important tests of heavy-quark decay models.

Contribution

First measurement of Lambda_b^0 lifetime in the J/psi Lambda^0 decay channel with high precision using D0 detector data.

Findings

Lambda_b^0 lifetime measured as 1.303 ps

B^0 lifetime measured as 1.508 ps

Lifetime ratio of Lambda_b^0 to B^0 is 0.864

Abstract

We measure the Lambda_b^0 lifetime in the fully reconstructed decay Lambda_b^0 -> J/psi Lambda^0 using 10.4 fb^-1 of ppbar collisions collected with the D0 detector at sqrt(s)=1.96 TeV. The lifetime of the topologically similar decay channel B^0 -> J/psi K^0_S is also measured. We obtain tau(Lambda_b^0) = 1.303 +- 0.075 (stat.) +- 0.035 (syst.) ps and tau(B^0) = 1.508 +- 0.025 (stat.) +- 0.043 (syst.) ps. Using these measurements, we determine the lifetime ratio of tau(Lambda_b^0)/tau(B^0) = 0.864 +- 0.052 (stat.) +- 0.033 (syst.).