Measurement of the Lambda_b lifetime in the exclusive decay Lambda_b to J/psi Lambda

Abstract

We have measured the Lambda_b lifetime using the exclusive decay Lambda_b to J/psi Lambda, based on 1.2 fb-1 of data collected with the D0 detector during 2002-2006. From 171 reconstructed Lambda_b decays, where the J/psi and Lambda are identified via the decays J/psi to mu+ mu- and Lambda to p pi, we measured the Lambda_b lifetime to be tau(Lambda_b) = 1.218(+0.130,-0.115)(stat) +/- 0.042(syst)ps. We also measured the B0 lifetime in the decay B0 to J/psi(mu+ mu-)K0_S(pi+ pi-) to be tau(B0) = 1.501(+0.078,-0.074)(stat) +/ -0.050(syst)ps, yielding a lifetime ratio of tau(Lambda_b)/tau(B0) = 0.811(+0.096,-0.087)(stat) +/ -0.034(syst). These measurements are consistent with the current world averages and support the shorter lifetime of the Lambda_b with respect to B mesons, in contrast to another recent measurement of significant precision.

This version has been accepted for publication in Physical Review Letters

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• Measurement of the Lambda_b lifetime using semileptonic decays
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• Measurement of the Lambda_b Lifetime in Lambda_b -> Lambda_c+ pi- Decays in p-pbar Collisions at sqrt(s) = 1.96 TeV
• 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
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