Search for macroscopic forces outside predictions from the Standard Model of cosmology have received particular attention by experimentalists in the last few decades. Understanding the fundamental forces of nature has always been an important part of physics. While the first such force studied was the gravitational force and our understanding of this interaction is extremely precise for relatively large separations among the interacting bodies, its validity at short distances has only recently been tested. Furthermore, the possibility of undetected light bosons, elementary particles governing the interaction between spin polarized bodies, is very poorly constrained. The groups plans to undertake an effort to gain a better understanding of these issues. By combining sample development and very precise measurements of the interactions between a source and a test mass, a much better knowledge of the interaction strength and mass of potential light bosons will be gained. The PI and co-PI will continue to attract undergraduate and high school students in physics and engineering to participate in the proposed work. Graduate students involved in the project will also have supervisory duties over undergraduate students, improving their leadership skills. Both PIs are minority members, and they will recruit students to participate in this research from underrepresented groups in physics. In particular the PI will use his position as co-advisor of the Society for the Advancement of Chicanos and Native Americans in Science (SACNAS)-IUPUI chapter to interest the Hispanic and Native American community in Science careers. Graduate students will be trained in two sub-disciplines in physics, precision measurements and magnetism. Demonstrations associated with the principles of forces, their actions at a distance and the decrease of their strength as the distance increases will be presented at community gathering events (School of Science Freshmen Picnic Day, Open Houses) and recruiting events and in the classroom environment.
Specifically, this proposal will: i) extend existing constraints for unpolarized masses at submicron range. This will be achieved mainly through a minor modification of the system previously used, ii) develop spin-polarized masses with no net magnetization. This development will be accomplished by the deposition of thin films in the required geometry, (iii) use the grown spin-polarized, zero magnetization films to constrain the existence of monopole-dipole interactions at short ranges, and (iv) study the systematic effect of the residual electrostatic forces present in the experiment. The ubiquitous problem encountered in the measurement of small forces at short separations arising from the effect of random electric potential on the surfaces of the test and source bodies will continue to be investigated.
