PROVO, Utah — Mormon church-owned Brigham Young University ended a six-decade ban Thursday on the sale of caffeinated soft drinks on campus, surprising students by posting a picture of a can of Coca-Cola on Twitter and just two words: “It’s happening.” The move sparked social media celebrations from current and former students, with many recalling how they had hauled their own 2-liter bottles of caffeinated sodas in their backpacks to keep awake for long study sessions. The university never banned having caffeinated drinks on campus, but held firm to the ban on sales even when The Church of Jesus Christ of Latter-Day Saints in 2012 clarified that church health practices do not prevent members from drinking caffeinated soft drinks. The ban has been in place since the mid-1950s.