Transverse single-spin asymmetries provide valuable information about the spin structure of the nucleon. At RHIC energies, heavy-flavor production is dominated by gluon-gluon fusion, and the subsequent decay into high p T electrons or muons can be observed statistically in a collider detector like PHENIX. The transverse single-spin asymmetry in heavy-flavor production originates from the initial state correlation between the internal transverse momentum of the parton and the transverse spin of the nucleon (similar with the known Sivers effect). The measurement of transverse single-spin asymmetry of single muons from heavy flavor decay at RHIC serves as a clean probe and would provide important information on the gluon Sivers function. In 2012, the PHENIX experiment collected 9.2 p b ? 1 integrated luminosity in transversely polarized p + p collisions at s = 200 GeV with a polarization of 6 0 % . The signal-to-background ratio was improved by a factor of two compared to the previous RHIC 2006 and 2008 results in high transverse momentum region ( p T > 3 GeV). The recent PHENIX preliminary results of transverse single-spin asymmetries of single heavy flavor decay muon at forward-rapidity will be shown and the possible improvement on this measurement in 2015 with the help of the FVTX detector will be discussed.
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