Measurement of the B+→pp̄K+ branching fraction and study of the decay dynamics

With a sample of 232×106 Υ(4S)→BB̄ events collected with the BABAR detector, we study the decay B+→pp̄K+ excluding charmonium decays to pp̄. We measure a branching fraction B(B+→pp̄K+)=(6.7±0.5±0.4)×10-6. An enhancement at low pp̄ mass is observed and the Dalitz plot asymmetry suggests dominance of the penguin amplitude in this B decay. We search for a pentaquark candidate Θ*++ decaying into pK+ in the mass range 1.43 to 2.00GeV/c2 and set limits on B(B+→Θ*++p̄)×B(Θ*++→pK+) at the 10-7 level. © 2005 The American Physical Society.