Two Republican state senators are joining an already crowded field of potential candidates for governor.Senator David Hann (han) of Eden Prairie says he is exploring a run and filed paperwork with state regulators yesterday.And Senator Mike Jungbauer (jung'-bow-er) of East Bethel announced his candidacy today.Both are two-term state senators, and join a crowd of declared or potential GOP candidates.Several DFL'ers are also running or thinking about it.