Wolfgang Altmannshofer, Reinard Primulando, Chiu-Tien Yu, Felix Yu
In view of the recent LHCb measurement of Delta A_CP, the difference between
the time-integrated CP asymmetries in D --> K+K- and D --> pi+pi- decays, we
perform a comparative study of the possible impact of New Physics degrees of
freedom on the direct CP asymmetries in singly Cabibbo suppressed D meson
decays. We systematically discuss scenarios with a minimal set of new degrees
of freedom that have renormalizable couplings to the SM particles and that are
heavy enough such that their effects on the D meson decays can be described by
local operators. We take into account both constraints from low energy flavor
observables, in particular D0-D0bar mixing, and from direct searches. While
models that explain the large measured value for Delta A_CP with chirally
enhanced chromomagnetic penguins are least constrained, we identify a few
viable models that contribute to the D meson decays at tree level or through
loop induced QCD penguins. We emphasize that such models motivate direct
searches at the LHC.
View original:
http://arxiv.org/abs/1202.2866
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