Context : Although a variety of techniques have been employed for determining the Milky Way dark matter halo mass distribution , the range of allowed masses spans both light and heavy values .
Knowing the precise mass of our Galaxy is important for placing the Milky Way in a cosmological \Lambda CDM context .

Aims : We show that hypervelocity stars ( HVSs ) ejected from the center of the Milky Way galaxy can be used to constrain the mass of its dark matter halo .

Methods : We use the asymmetry in the radial velocity distribution of halo stars due to escaping HVSs , which depends on the halo potential ( escape speed ) as long as the round trip orbital time is shorter than the stellar lifetime , to discriminate between different models for the Milky Way gravitational potential .

Results : Adopting a characteristic HVS travel time of 330 Myr , which corresponds to the average mass of main sequence HVSs , we find that current data favors a mass for the Milky Way in the range ( 1.2 - 1.9 ) \times 10 ^ { 12 } \mathrm { M } _ { \odot } .

Conclusions :