Evidence for the charmless annihilation decay mode Bs0→π +π

Aaltonen, T. et al.
We search for annihilation decay modes of neutral b mesons into pairs of charmless charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 6 fb-1 of integrated luminosity, we obtain the first evidence for the Bs0→π+π- decay, with a significance of 3.7σ, and a measured branching ratio B(Bs0→π+π-)=(0.57±0.15(stat)±0.10(syst))×10-6. A search for the B0→K+K- mode in the same sample yields a significance of 2.0σ, and a central value estimate B(B0→K+K-)=(0.23±0.10(stat)±0.10(syst))×10-6.
This work was supported by the U.S. Department of Energy and National Science Foundation; the Italian Istituto Nazionale di Fisica Nucleare; the Ministry of Education, Culture, Sports, Science and Technology of Japan; the Natural Sciences and Engineering Research Council of Canada; the National Science Council of the Republic ofChina; the Swiss National Science Foundation; the A. P. Sloan Foundation; the Bundesministerium für Bildung und Forschung, Germany; the Korean World Class University Program, the National Research Foundation of Korea; the Science and Technology Facilities Council and the Royal Society, UK; the Russian Foundation for Basic Research; the Ministerio de Ciencia e Innovación, and Programa Consolider-Ingenio 2010, Spain; the Slovak R&D Agency; the Academy of Finland; and the Australian Research Council (ARC).