Signals of Leptophilic Dark Matter at the ILC

Adopting a model independent approach, we constrain the various effective interactions of leptophilic DM particle with the visible world from the WMAP and Planck data. The thermally averaged indirect DM annihilation cross-section and the DM-electron direct-detection cross-section for such a DM candidate are observed to be consistent with the respective experimental data. We study the production of cosmologically allowed leptophilic DM in association with $Z\, (Z\to f\bar f)$, $f\equiv q,\,e^-,\, \mu^-$ at the ILC. We perform the $\chi^2$ analysis and compute the 99\% C.L. acceptance contours in the $m_\chi$ and $\Lambda$ plane from the two dimensional differential distributions of various kinematic observables obtained after employing parton showering and hadronization to the simulated data. We observe that the dominant hadronic channel provides the best kinematic reach of 2.62 TeV ($m_\chi$ = 25 GeV), which further improves to 3.13 TeV for polarized beams at $\sqrt{s} = 1$ TeV and an integrated luminosity of 1 ab$^{-1}$.