Project Grant 60NANB24D321

PURPOSE: THE PURPOSE OF THIS GRANT IS TO REALIZE ONE OF THE MOST STRINGENT TESTS OF QUANTUM ELECTRODYNAMICS, YIELDING INDEPENDENT DETERMINATIONS OF THE RYDBERG AND FINE STRUCTURE CONSTANTS, THAT ARE PIVOTAL IN THE CODATA LEAST-SQUARES ADJUSTMENTS UNDERTAKEN BY NIST UNDER THE AUSPICES OF THE INTERNATIONAL SCIENCE COUNCIL'S COMMITTEE ON DATA (CODATA). ADDITIONALLY, IT WILL PROVIDE AN IMPROVED AND RELIABLE MUON MASS FOR THE MUON G-2 THEORY THAT CAN BE CONFRONTED WITH NEW EXPERIMENTS UNDERWAY AT FERMILAB.ACTIVITIES TO BE PERFORMED: THE RESEARCHERS WILL MEASURE THE 1S-2S TRANSITION FREQUENCY OF MUONIUM TO A PRECISION OF 10 KHZ (OR 4 PARTS PER TRILLION), WHICH WOULD BE AN IMPROVEMENT OF A FACTOR OF 1000 COMPARED TO PRIOR MEASUREMENTS. THIS IS ENABLED BY THE HIGHER FLUX OF MUONS AVAILABLE AT THE PAUL SCHERRER INSTITUTE (PSI), AS WELL AS OTHER TECHNICAL MILESTONES, SUCH AS ATTAINING 25W OUTPUT FROM THE DEEP-UV LASER AT 244 NM FOR EXCITING THE 1S-2S TRANSITION.EXPECTED OUTCOMES: SUCCESS IS EXPECTED TO PROVIDE ALMOST TWO ORDERS OF MAGNITUDE IMPROVEMENT IN THE VALUE OF THE MUON MASS. IT WILL ALSO LEAD TO A VALUE FOR THE RYDBERG CONSTANT THAT IS INDEPENDENT OF THE NUCLEAR AND FINITE-SIZE EFFECTS AT A LEVEL OF 1 PART IN 1012.INTENDED BENEFICIARIES: INSTITUTIONS OF HIGHER LEARNING WILL BENEFIT FROM PRECISELY TESTING THE BASIC LAWS OF NATURE. THE CODATA LEAST-SQUARES ADJUSTMENT OF FUNDAMENTAL CONSTANTS WOULD BE STRENGTHENED, THUS BENEFITING NIST AND OTHER METROLOGICAL INSTITUTES CHARGED WITH IMPLEMENTING THE NEW SI SYSTEM OF UNITS BASED UPON FUNDAMENTAL CONSTANTS. INDIRECTLY, VARIOUS HIGH-TECH INDUSTRIES WILL ALSO BENEFIT FROM MORE ACCURATE CONSTANTS OF NATURE.SUBRECIPIENT ACTIVITIES: THERE ARE NO SUBAWARDS IN THIS PROJECT.