For four decades, particle physicists trying to predict how mesons built around a single heavy bottom or charm quark actually decay have reached for a toolkit that Mark B. Wise helped build. Wise, the John A. McCone Professor of High Energy Physics at the California Institute of Technology, died July 10, 2026, at age 72, Caltech announced.

Born November 9, 1953, in Montreal, Quebec, Wise studied physics at the University of Toronto, where as an undergraduate he was mentored by the young theorist Nathan Isgur. He earned a bachelor's degree in 1976 and a master's the following year, then moved to Stanford University, completing a PhD in 1980 and working at the Stanford Linear Accelerator Center. From 1980 to 1983 he was a Junior Fellow at the Harvard Society of Fellows, and in 1982 he joined the Caltech faculty as an assistant professor. He was promoted to associate professor in 1984 and to full professor in 1985, and in 1992 was named the John A. McCone Professor of High Energy Physics, a chair he held for the remainder of his career.

At Caltech, working alongside colleagues including Joe Polchinski and David Politzer, Wise became a principal architect of heavy quark effective theory, a framework that let physicists make precise, quantitative predictions about the strong nuclear force acting on hadrons containing a single heavy quark. In 2001 the American Physical Society awarded Wise, Nathan Isgur, the same theorist who had once mentored him as an undergraduate, and Mikhail Voloshin the J.J. Sakurai Prize for Theoretical Particle Physics for the construction of the heavy quark mass expansion and the discovery of the heavy quark symmetry in quantum chromodynamics, which led to a quantitative theory of the decays of c and b flavored hadrons, according to the American Academy of Arts and Sciences, which elected Wise a fellow the following year. He was also elected to the National Academy of Sciences and, in 2021, received the Julius Wess Award from the Karlsruhe Institute of Technology.

Wise's gift for explaining difficult physics simply enough to be useful reached beyond the seminar room. In 2009 the National Academy of Sciences' Science and Entertainment Exchange asked him to help ground the science of Iron Man 2, and later that year he and Caltech graduate student Tim Dulaney spent two hours at Marvel Studios advising on how the film's hero might discover a new element. "We discussed using the buildings to represent electrons in an atom," Wise said of the resulting sequence, adding of the filmmakers' intentional vagueness, "Being vague is to their credit." After the film opened, he admitted he had enjoyed it: "I actually liked it a lot. But I'm a huge fan of these kinds of movies," he told Caltech.

Colleagues remembered a scientist as generous with students as he was rigorous with equations. "Mark was a distinguished scientist and a dedicated teacher and mentor, deeply committed to his students and postdoctoral scholars," said Hirosi Ooguri, Caltech's Fred Kavli Professor of Theoretical Physics and Mathematics. "He was also a kind and generous colleague whose counsel I always valued. I will miss him."

Wise spent forty-four years on the Caltech faculty, longer than most of the students he trained had been alive. The equations of heavy quark effective theory still do the work he built them to do, turning raw particle-collider data into quantitative answers about how the heaviest quarks decay, and the physicists he mentored carry that method of thinking into laboratories he never visited.