The rest frame subjet algorithm is introduced to define the subjets for the SISCone jet. Using it, an IR and collinear safe jet shape observable N-subjettiness, $tau_N^{j}$, is defined to discriminate the fat jet from a highly boosted color singlet p
article decaying to N partons and the QCD jet. Using rest frame subjets and $tau_2^{j}$ on dijets from highly boosted $it H / W / Z$ bosons through $pp to it H W$, $it H Z$, we found that statistical significance of the signal is about $2 sigma$ at the LHC with $mathcal{L} sim 30 mathrm{fb^{-1}}$ at $14 tev$.
