Can up FCNC solve the Δ ACP puzzle?
Abstract
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 ΔACP is completely excluded by the D0-Dbar0 mixing. We conclude that the up FCNC type models cannot explain the ΔACP while to be consistent with the D0-Dbar0 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 ΔACP consistently.
- Publication:
-
Physics Letters B
- Pub Date:
- March 2012
- DOI:
- 10.1016/j.physletb.2012.02.021
- arXiv:
- arXiv:1111.5196
- Bibcode:
- 2012PhLB..709..362W
- Keywords:
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- High Energy Physics - Phenomenology
- E-Print:
- 10 pages, 2 figures