1. Can the CNB be detected by a torsion balance? B. Heckel, Univ. of Washington

2. feet pendulum magnetic shielding thermal shield compensation masses HH coils prehanger fiber vacuum can autocollimator turntable (  ) ()()

4. 4 Can the CNB be detected by a torsion balance? Hagmann, astro-ph/9902102 Ringwald, arXiv:0901.1529 Stodolsky, MPI-PAE/PTh 1/90 Braginsky, Klapdov, et al,

5. Relic Neutrinos T  = 1.95 K = 56 / cm 3 N  =  n = 300 /cm 3 p = 5 x 10 -4 eV ; at least 2 species non-relativistic; assume all non-relativistic Gravitational clustering provides a density enhancement of 1.5-20; assume 10 Isotropically distributed in galaxy; Earth’s motion has v/c = 10 -3 Flux = 300 x 10 x 10 -3 c = 10 11 /cm 2 -s

6. Smaller by (v/c) 2 for Majorana neutrinos ?

7. is possible, but still too large by 10 12 If all of the neutrons in 30g target scattered neutrinos coherently,  a would be 10 -19 cm/s 2 30 g 3 cm 30 g If all of the neutrinos incident on the 30g target scattered coherently,  a would be 10 -16 cm/s 2

8. Conclusions The coherent scattering of relic neutrinos leads to a large enhancement of the scattering cross section. Current torsion balance test masses scatter roughly 1 relic neutrino per second. But the momentum transfer is too small to be observable. I wouldn’t fund this experiment.