Neutrino forces in neutrino backgrounds

A bstract The Standard Model predicts a long-range force, proportional to $$ {G}_F^2/{r}^5 G F 2 / r 5 , between fermions due the exchange of pair neutrinos. This quantum force is feeble and has not been observed yet. In this paper, we compute in presence neutrino backgrounds, both for isotropic directional background We find that case can have 1 /r dependence it be significantly enhanced compared vacuum case. particular, effects caused by reactor, solar, supernova neutrinos enhance many orders magnitude. enhancement, however, occurs only direction parallel discuss experimental prospects detecting backgrounds effect close available sensitivity current fifth experiments. Yet, angular spread flux test masses reduce strength force. results are encouraging detailed study called check if probed.