No. Central banks cannot create a new currency.
Actual usage of Bitcoin / Bitcoin Cash / Bitcoin Gold can be assimilated, they're all tradable coins. In a functional way, these Bitcoin clones act like new notes printed by central banks, they create inflation.
Like I said, it's just a scenario, but I think it deserves some thoughts. We're less than 4 months into this new "cloning and printing" strategy and a lot can happen.