A new test of the weak equivalence principle

One of the fundamental tenets of the General Theory of Relativity is the Equivalence Principle: all forms of matter have the same acceleration in a uniform gravitational field. This thesis describes a new test of the Weak Equivalence Principle (WEP) based on a comparison of the accelerations due to the gravity of the earth, of Beryllium and Aluminum, and Beryllium and Copper test bodies. The accelerations are also used to search for a conjectured new composition-dependent macroscopic interaction with a range larger than 1 meter that would arise from the exchange of undiscovered scalar or vector bosons with masses less than 0.2 {dollar}times{dollar} 10{dollar}sp{lcub}-6{rcub}{dollar} eV.; The basic experimental technique is to compare the horizontal accelerations of different test bodies by measuring the torque on a torsion balance, which rotates continuously relative to the gravitational field of the earth, and relative to a nearby hillside that could serve as the source for short range composition-dependent forces.; Our experimental results of the horizontal differential accelerations are (1-{dollar}sigma{dollar} error): {dollar}vec{lcub}a{rcub}sbsp{lcub}perp{rcub}{lcub}rm Be{rcub} - vec{lcub}a{rcub}sbsp{lcub}perp{rcub}{lcub}rm Al{rcub}{dollar} = (({dollar}-{dollar}0.6 {dollar}pm{dollar} 5.6)e + ({dollar}-{dollar}4.4 {dollar}pm{dollar} 5.6)n)) {dollar}times{dollar} 10{dollar}sp{lcub}-12{rcub}{dollar}cm/sec{dollar}sp2,{dollar} and {dollar}vec{lcub}a{rcub}sbsp{lcub}perp{rcub}{lcub}rm Be{rcub} - vec{lcub}a{rcub}sbsp{lcub}perp{rcub}{lcub}rm Cu{rcub}{dollar} = ((3.0 {dollar}pm{dollar} 6.8)e + ({dollar}-{dollar}2.6 {dollar}pm{dollar} 6.8)n)) {dollar}times{dollar} 10{dollar}sp{lcub}-12{rcub}{dollar}cm/sec{dollar}sp2,{dollar} where e and n represent the unit vectors pointing to East and North, respectively. From this, we concluded that the WEP holds to about 8 parts in 10{dollar}sp{lcub}12{rcub}{dollar} with 95% confidence level. No evidence for new interactions was found. Our results set a limit on the coupling strength of an interaction coupled to Baryon number with a range {dollar}lambda{dollar} = 100 m to be 3 {dollar}times{dollar} 10{dollar}sp{lcub}-6{rcub}{dollar} weaker than gravity (95% confidence).