Since they intend to create a Palestinian state, Jordan’s border would likely remain the same. Otherwise, yes, Jordan.
Of course, the Jordanian government does not want the territory back because they do not want any more “Palestinians” inside their borders. They remember that a Palestinian assassinated the King of Jordan in 1951.
On 20 July 1951, while visiting Al-Aqsa Mosque in Jerusalem, King Abdullah was shot dead by a Palestinian, described as a “former terrorist.” He was shot while attending Friday prayers at the Al-Aqsa Mosque in the company of his grandson, Prince Hussein. The Palestinian gunman was of a faction that later became the PLO and now the Palestinian Authority. He fired three fatal bullets into the King’s head and chest. Abdullah’s grandson, Prince Hussein, was at his side and was hit too. Once Hussein became king, the assassination of Abdullah was said to have influenced Hussein not to enter peace talks with Israel in the aftermath of the 1967 Six-Day War in order to avoid a similar fate.
Every time I hear about the holiness of the Al-Aqsa mosque, I remember this event.