Studies in Experimental Nuclear Physics at Indiana University

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The Indiana nuclear physics group plans to assume a leading role in theinvestigation of the following critical questions in nuclear physics.The spin of the proton is an essential property that determines thestructure of matter, yet we know that only a small part of the spincomes from the three quarks that form the proton. The STAR-SPIN groupwould definitively measure the contribution from the gluons, theshort-lived particles that hold the quarks together and which accountfor much of its mass to see if that is where the missing spinresides.The measurement of the gluon contribution to the proton spinwill be carried out by adding a special detector for high energy gammarays to the STAR detector located at the Relativistic Heavy IonCollider. The detector is now being built using separate NSFconstruction funds. The force between pairs of neutrons and protons cannot, by itself,account for the strength that binds the nucleus together. New,three-body forces are needed, but their form is almost unknown. Bymanipulating the neutron and proton spins when three of them cometogether, the PINTEX collaboration would produce a map to guide a theoryof such three-body force. . FY2002 will be the last year of data takingusing the intense beams and unique capabilities of the IndianaUniversity Cooler Facility to study these three-body forces. The weak force between nucleons, which can change the form of matter, is still poorly understood. By making a measurement accurate to one part in a billion on the formation of a deuteron from a neutron and a proton, the IU neutron group would measure the longest-range part of the weak force . The Indiana group would support studies of the weak force and other effects accessible using cold neutrons at NIST and LANSCE and byproviding crucial parts of the experimental apparatus. There is mounting evidence that neutrinos, one of the most ubiquitousparticles in the universe, may have mass, thus changing our most eleganttheories of matter and how it controls the expansion of the universe. The neutrino group would check a recent observation from LANL of a fewcases where neutrinos, because they have mass, spontaneously change fromone neutrino type into another by collecting a large enough data sampleto settle this issue. A key component of the Indiana program will be the training of studentsto become the next generation of researchers. This effort includes theinvolvement of post-doctoral associates in critical experimental roles,guiding the research of graduate students, involving undergraduatesthrough the NSF-funded REU summer program and part-time employment, andreaching out to make the community aware of our scientific mission.