| M.J. Drinkwater (2007) | |||||||||||||
Abstract | |||||||||||||
| . We have compared the frequency of high-redshift Hydrogen HI 21 cm absorption with that of associated molecular absorption in two quasars to place new (1 sigma) upper limits on any variation in y j gp ff 2 (where ff is the fine structure constant and gp is the proton g-factor) of \Deltay=y ! 5 \Theta 10 \Gamma6 at redshifts z = 0:25 and z = 0:68. 1 Introduction Recent measurements of molecular absorption in some radio sources corresponding to known HI 21cm absorption systems give us ideal laboratories in which we can search for any possible temporal and spatial variation in the fundamental constants of Nature (a summary is given in [6]). The rotational transition frequencies of diatomic molecules such as CO are proportional to ¯h=(Ma 2 ) where M is the reduced mass and a = ¯h 2 =(m e e 2 ) is the Bohr radius. The 21 cm hyperfine transition in hydrogen has a frequency ¸ ¯ p ¯B =(¯ha 3 ), where ¯ p = g p e¯h=(4m p c), g p is the proton g-factor and ¯B = e¯h=(2m e c). Cons... | |||||||||||||
Publication details | |||||||||||||
| |||||||||||||