Direct CP violation of B→lν in unparticle physics

We have investigated the effects of unparticles in decays B→lν. It is found that the direct CP violation in the decays, which is zero in the standard model, can show up due to the CP conserving phase intrinsic in unparticle physics. For l=τ, the direct CP asymmetry can reach 30% for the scalar unparticle contribution, and 100% for the longitudinal vector unparticle contribution under the constraints of Br(B→τν) and νe elastic scattering. If both unparticle-lepton coupling universality and unparticle-quark coupling universality are assumed the constraint from Br(π→μν) leads that the direct CP violation in B→lν can only reach at most 8% and 1% for scalar and vector unparticle contributions, respectively, if dU<2. If the direct CP violation is observed in the future it would give strong evidence for the existence of unparticle stuff.