Gravitational redshift in Einstein-Kalb-Ramond spacetime and Randall-Sundrum scenario

It is shown that the gravitational red-shift, as. predicted by-Einstein's theory is modified in the presence of a second-rank antisymmetric tensor (Kalb-Ramond) field in a string-inspired background spacetime. In the presence of extra dimensions. the Randall-Sundrum brave world scenario is found to play a crucial role ill suppressing this additional shift. The bound on the value of the warp factor is 'determined front the redshift data and is found to be in excellent agreement with that determined from the requirements of the standard model.