actually, Jews also disseminated in Arabia and into Persia, and Mohammed forcibly converted many, so there could be many of Jewish heritage among Arab Moslems
There were a lot of Jews in Yathrib (Medina) at the time of the Hegira in 622—but it’s possible that some of the Arabian Jews of that period were descendants from converts rather than from the original Israelites. There were Jews in a town or oasis in NW Arabia who made a treaty with Muhammad and were allowed to stay there, and I once saw something from the late 19th or early 20th century which implied that they were still there, but I don’t know if that information was correct then (let alone now).