  Ramanujan provided several results involving the modified Bessel function
$K_z(x)$ in his Lost Notebook. One of them is the famous Ramanujan-Guinand
formula, equivalent to the functional equation of the non-holomorphic
Eiesenstien series on $SL_2(z)$. Recently, this formula was generalized by
Dixit, Kesarwani, and Moll. In this article, we first obtain a generalization
of a theorem of Watson and, as an application of it, give a new proof of the
result of Dixit, Kesarwani, and Moll. Watson's theorem is also generalized in a
different direction using ${}_\mu K_z(x,\lambda)$ which is itself a
generalization of $K_z(x)$. Analytic continuation of all these results are also
given.
