We performed a spectroscopic search for binaries among hot Horizontal Branch stars in globular clusters .
We present final results for a sample of 51 stars in NGC 6752 , and preliminary results for the first 15 stars analyzed in M 80 .
The observed stars are distributed along all the HBs in the range 8000 \leq T _ { \mathrm { eff } } \leq 32000 K , and have been observed during four nights .
Radial velocity variations have been measured with the cross-correlation technique .
We carefully analyzed the statistical and systematic errors associated with the measurements in order to evaluate the statistical significance of the observed variations .
No close binary system has been detected , neither among cooler stars nor among the sample of hot EHB stars ( 18 stars with T _ { \mathrm { eff } } \geq 22000 K in NGC 6752 ) .
The data corrected for instrumental effects indicate that the radial velocity variations are always below the 3 \sigma level of \approx 15 km s ^ { -1 } .
These results are in sharp contrast with those found for field hot subdwarfs , and open new questions about the formation of EHB stars in globular clusters , and possibly of the field subdwarfs .