After following integral, I got a MeijerG result,
Integrate[(1/(2 r (1 + r^2))*Sin[r])^2*r, {r, 0, \[Infinity]}]
Out=1/16 Sqrt[\[Pi]] MeijerG[{{1, 1}, {}}, {{1, 2}, {0, 1/2}}, 1]
I don't know what is MeijerG[{{1, 1}, {}}, {{1, 2}, {0, 1/2}}, z],
I tried Activate command, it gives same result.
So I checked online and found MeijerG function in Mathematica should be:
MeijerG[{{a1,...,an},{an+1,...,ap}},{{b1,...,bm},{bm+1,...,bq}},z,]
So I believe bm+1 should be greater than bm and so does bq is greater than bm too.
However, the MeijerG function I got is MeijerG[{{1, 1}, {}}, {{1, 2}, {0, 1/2}}, 1],
bm=2 and bm+1=0 and bq=1/2, which means both bm+1 and bq is less than bm.
I am confused. Anyone can help me? I don't think this is a mistake of Mathematica.