Scalar dark matter search at the LHC through flavor-changing neutral current top decay.

We discuss an extended standard model electroweak sector which contains a stable scalar dark matter particle, the D boson. To search for the D boson at the LHC we exploit the flavor-changing neutral current top quark decay, t→cDD, mediated by the lightest standard model-like Higgs h0 in a two Higgs doublet model framework. The branching ratio for t→cDD in this case can be as high as 10-3, after taking into account constraints arising from the D boson relic abundance. With an integrated luminosity of 10(100) fb-1, the 14 TeV LHC can explore values of this branching ratio that are one (two) order of magnitude smaller in tt¯ production with tt¯ →cb¯ ℓ-(c¯bℓ+)+ET. For a D boson mass ≲60 GeV, mh0≲2MZ, 10 fb-1 luminosity and a branching ratio BR(t→cDD)~10-4, the estimated number of signal events at the 14 TeV LHC is of order 80. [ABSTRACT FROM AUTHOR]