A dispute regarding the status of the territories was settled by an Arbitrator appointed by the Council of the League of Nations. It was decided that Palestine and Transjordan were newly created states according to the terms of the applicable post-war treaties.
State of Palestine - Wikipedia, the free encyclopedia
And as even most grade-schoolers know the soon-to-be Israelis - operating under the auspices of UN 181 - declared their independence, named their new state Israel and gained both UN membership and international recognition. The region's Arabs took a somewhat different route:
"On the eve of final British withdrawal, the Jewish Agency for Israel
declared the establishment of the State of Israel according to the proposed UN plan. The Arab Higher Committee didn't declare a state of its own and instead, together with Transjordan, Egypt, and the other members of the Arab League of the time, started the 1948 ArabIsraeli War"
State of Palestine - Wikipedia, the free encyclopedia