Search for Lambda_b -> p pi and Lambda_b -> p K decays in p-pbar collisions at sqrt(s) = 1.96 TeV

TL;DR

This study searched for specific Lambda_b baryon decays into proton and pion or kaon in proton-antiproton collisions at 1.96 TeV, setting upper limits on their branching fractions due to no observed signal.

Contribution

It provides the first upper limits on Lambda_b -> p pi- and p K- decay branching fractions in proton-antiproton collisions at Tevatron energies.

Findings

No Lambda_b signal observed.

Upper limits on branching fractions set at 2.3x10^-5 (90% C.L.) and 2.9x10^-5 (95% C.L.).

Used optimized track trigger for secondary vertex detection.

Abstract

We report on a search for Lambda_b -> p pi- and Lambda_b -> p K- (and charge conjugate) decays in p-pbar collisions at sqrt(s) = 1.96 TeV using 193 pb-1 of data collected by CDFII experiment at the Fermilab Tevatron Collider. Data were collected using a track trigger that has been optimized to select tracks belonging to a secondary vertex that is typical of two body charmless decays of b-flavored hadrons, including Lambda_b baryons. As no Lambda_b signal was observed, we set the upper limits on the branching fractions BR(Lambda_b -> p h-) where h is K or pi, of 2.3x10-5 at 90% C.L. and 2.9x10-5 at 95% C.L.