We investigate the attempt using flavor violation gauge interaction in the up sector to explain the LHCb recently observed large δACP(ACP(D0→K+K-)-ACP(D0→π+π-)). We study an Abelian model that only right-handed up quarks is charged under it and the 1-3 coupling is maximized. The simultaneous 1-3 2-3 mixing is realized by a quark mixing of 1-2 generation. Given the easy identification of top quark, the model can be directly tested by δF=1 and δF=2 processes at the hadron colliders as associated top production gc→tZ'or same-sign top scattering uu→tt. The direct search bounds are still consistent with the assumption that ut and ct couplings are equal but the same-sign top scattering bound is expected to be reached very soon. However, since there is no CKM-like suppression, the corresponding parameter space for generating δACPis completely excluded by the D0-D-0 mixing. We conclude that the up FCNC type models cannot explain the δACPwhile to be consistent with the D0-D-0 mixing constraint at the same time. On the other hand, a model as SM with fourth family extension has better chance to explain the large δACPconsistently. © 2012 Elsevier B.V.
Wang, K., & Zhu, G. (2012). Can up FCNC solve the δACPpuzzle? Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 709(4–5), 362–365. https://doi.org/10.1016/j.physletb.2012.02.021