Yes, looks like a cut. Do you have a photo of the inside of the tire at the cut?
I rarely see any reports of tires exploding. And those few are often a long, ragged split near the tire bead, with casing threads hanging loose.
That 27x1.9 is about 48 mm wide. Panaracer says max 50 psi.
Try 30 psi! It's way more comfortable and just as fast. (You might want to lower the pressure in stages over a couple of rides. Just to adapt to the new road feel. A jump from rock hard to flexing over rough surfaces might feel a bit weird at first.)