I am trying to find a closed form expression of an integral containing a product of bessel functions. Sage returns my command instead of a solution. Any help is appreciated. My code is below. I am solving this on a free CoCalc server.
phi, l, R, r_bar= var('phi l R r_bar')
phi = bessel_J(0, l*R) - (bessel_J(0,l*r_bar)*bessel_Y(0,l*R))/(bessel_Y(0,l*r_bar))
f = R*phi*phi
integrate(f, R)
