Rosemary Fowler
Rosemary Fowler is a British physicist who in 1948 as a 22-year-old doctoral researcher discovered the kaon. While studying photographic plates that had been left exposed to cosmic rays, she identified a new configuration of tracks within the photographic emulsion that she recognised as being the decay of an unknown charged particle. Her discovery contributed to the introduction into particle physics of the property of strangeness, and to physicists' understanding that parity is not conserved in weak interactions – features that now form an integral part of the Standard Model of particle physics.
Early life and education
Born in Suffolk in 1926, Brown grew up in Malta, Portsmouth and finally Bath, as her family moved to follow the postings of her father, a Royal Naval engineer. At school in wartime Bath, she excelled in maths and science, and was the only girl in her year to go to university. In 1947, she became one of the first women to gain first class honours in physics at the University of Bristol.Research
After graduating from Bristol, Brown became a doctoral researcher in the group of Cecil Powell, a British physicist and pioneer in the use of nuclear emulsion coated plates to investigate cosmic rays entering the Earth's atmosphere. Powell and his team had achieved success with these techniques, and had already discovered a theorised particle, the pi meson or pion.File:The "k track plate" showing three-pion decay mode of a kaon, 15 Jan 1949.png|thumb|The "k track" plate showing three-pion decay of a positively-charged kaon. The kaon enters at left and decays into a meson and two mesons. The meson then interacts with a nucleus in the emulsion at B.
Working alongside her fellow PhD student and future husband Peter Fowler, Brown studied the tracks left on stacks of photographic plates that were exposed to cosmic rays at the Sphinx Observatory, a high-altitude laboratory at Jungfraujoch, Switzerland. When Minnie van der Merwe, one of the team of "scanners", passed her a plate with an unusual configuration of tracks, Brown recognised it as a candidate for the decay of a new meson, called at that time the 'tau meson'. The group published their findings in a 1949 paper in Nature which included a photograph of what became known as the 'k track' plate.
Brown's 'tau meson' appeared similar to the 'theta meson' that had been discovered earlier by G.D. Rochester and C.C. Butler of the University of Manchester, except that it decayed into three pions rather than the two of the 'theta meson'. Since the two decay paths have different parities, the physics of the time suggested that in spite of their apparent similarity the particles could not be the same. The puzzle was later resolved by the introduction into the theory of a new strangeness quantum number, and by the 1957 experimental discovery that parity was not conserved by the weak interaction.
Powell was awarded the Nobel Prize for Physics in 1950 "for his development of the photographic method of studying nuclear processes and his discoveries regarding mesons made with this method."
Personal life and legacy
Rosemary Brown and Peter Fowler married in 1949. She never completed her doctorate, but continued to assist her husband while raising their three daughters – one of whom, the geophysicist Mary Fowler, became Master of Darwin College, Cambridge.In 2004, Rosemary Fowler supported the Royal Astronomical Society to establish the Fowler award for early achievement in astronomy, in memory of her husband Peter and her father-in-law Ralph H. Fowler.