Article 8 of the Arizona State Constitution:
Text of Section 1:
Officers Subject to Recall; Petitioners
Every public officer in the state of Arizona, holding an elective office, either by election or appointment, is subject to recall from such office by the qualified electors of the electoral district from which candidates are elected to such office. Such electoral district may include the whole state. Such number of said electors as shall equal twentyfive per centum of the number of votes cast at the last preceding general election for all of the candidates for the office held by such officer, may by petition, which shall be known as a recall petition, demand his recall.
Article I, Section 5 of the U.S. Constitution:
"Each House may determine the rules of its proceedings, punish its members for disorderly behavior, and, with the concurrence of two thirds, expel a member."
And that is the only way a sitting Senator can be removed from office.
Officers Subject to Recall; Petitioners
Every public officer in the state of Arizona, holding an elective office, either by election or appointment, is subject to recall from such office by the qualified electors of the electoral district from which candidates are elected to such office.
Well and good. Except that, upon election, U.S. Senators and U.S. Congressmen are federal officers; they are not subject to state law.
They cannot be recalled. Period (which, in this case, is an accurate use of the exclusive term).