A study of B ± → J / ψ π ± and B ± → ψ ( 2 S ) π ± decays is performed with data corresponding to 0.37     fb − 1 of proton-proton collisions at √ s = 7     TeV . Their branching fractions are found to be B ( B ± → J / ψ π ± ) = ( 3.88 ± 0.11 ± 0.15 ) × 10 − 5 and B ( B ± → ψ ( 2 S ) π ± ) = ( 2.52 ± 0.26 ± 0.15 ) × 10 − 5 , where the first uncertainty is related to the statistical size of the sample and the second quantifies systematic effects. The measured C P asymmetries in these modes are A J / ψ π C P = 0.005 ± 0.027 ± 0.011 and A ψ ( 2 S ) π C P = 0.048 ± 0.090 ± 0.011 with no evidence of direct C P violation seen.