Measurement of b-hadron branching fractions for two-body decays into charmless charged hadrons

Based on data corresponding to an integrated luminosity of 0.37 fb−1 collected by the LHCb experiment in 2011, the following ratios of branching fractions are measured: $ {array}{*{20}{c}} {{{{B( {B^0 → {π⁺}{π⁻}} )}} / {{B( {B^0 → {K⁺}{π⁻}} )}} .}=0.262± 0.009± 0.017,} \\ {( {{f_s / {f_d } .}} )· {{{B( {B_s^0→ {K⁺}{K⁻}} )}} / {{B( {B^0 → {K⁺}{π⁻}} )}} .}=0.316± 0.009± 0.019,} \\ {( {{f_s / {f_d } .}} )· {{{B( {B_s^0→ {π⁺}{K⁻}} )}} / {{B( {B^0 → {K⁺}{π⁻}} )}} .}=0.074± 0.006± 0.006,} \\ {( {{f_d / {f_s } .}} )· {{{B( {B^0 → {K⁺}{K⁻}} )}} / {{B( {B_s^0→ {K⁺}{K⁻}} )}} .}=0.018-0.007+0.008± 0.009,} \\ {( {{f_s / {f_d } .}} )· {{{B( {B_s^0→ {π⁺}{π⁻}} )}} / {{B( {B^0 → {π⁺}{π⁻}} )}} .}=0.050-0.009+0.011± 0.004,} \\ {{{{B( {Λ_b^0→ p{π⁻}} )}} / {{B( {Λ_b^0→ p{K⁻}} )}} .}=0.86± 0.08± 0.05,} \\ {array} $ where the first uncertainties are statistical and the second systematic. Using the current world average of $ B( {B^0 → {K⁺}{π⁻}} ) $ and the ratio of the strange to light neutral B meson production f s /f d measured by LHCb, we obtain: $ {array}{*{20}{c}} {B( {B^0 → {π⁺}{π⁻}} )=( {5.08± 0.17± 0.37} )× {10⁻⁶},} \\ {B( {B_s^0→ {K⁺}{K⁻}} )=( {23.0± 0.7± 2.3} )× {10⁻⁶},} \\ {B( {B_s^0→ {π⁺}{K⁻}} )=( {5.4± 0.4± 0.6} )× {10⁻⁶},} \\ {B( {B^0 → {K⁺}{K⁻}} )=( {0.11-0.04+0.05± 0.06} )× {10⁻⁶},} \\ {B( {B_s^0→ {π⁺}{π⁻}} )=( {0.95-0.17+0.21± 0.13} )× {10⁻⁶}.} \\ {array} $ The measurements of $ B( {B_s^0→ {K⁺}{K⁻}} ) $ , $ B( {B_s^0→ {π⁺}{K⁻}} ) $ and $ B( {B^0 → {K⁺}{K⁻}} ) $ are the most precise to date. The decay mode $ B_s^0→ {π⁺}{π⁻} $ is observed for the first time with a significance of more than 5σ.