A precise measurement of the anomalous g value, a+μ = (g − 2)/2, for the positive muon has been made at the Brookhaven Alternating Gradient Synchrotron. The result a+μ = 11 659 202(14)(6) × 10−10 (1.3 ppm) is in good agreement with previous measurements and has an error one third that of the combined previous data. The current theoretical value from the standard model is aμ(SM)= 11 659 159.6(6.7) × 10−10 (0.57 ppm) and aμ(exp)−aμ(SM) = 42(16) × 10−10 in which aμ(exp) is the world average experimental value.
