| Итог: | <p>We present the first results of the Fermilab National Accelerator Laboratory (FNAL) Muon <span tabindex="0">g−2</span> Experiment for the positive muon magnetic anomaly <span tabindex="0">aμ≡(gμ−2)/2</span>. The anomaly is determined from the precision measurements of two angular frequencies. Intensity variation of high-energy positrons from muon decays directly encodes the difference frequency <span tabindex="0">ωa</span> between the spin-precession and cyclotron frequencies for polarized muons in a magnetic storage ring. The storage ring magnetic field is measured using nuclear magnetic resonance probes calibrated in terms of the equivalent proton spin precession frequency <span tabindex="0">˜ω′p</span> in a spherical water sample at <span tabindex="0">34.7 °C</span>. The ratio <span tabindex="0">ωa/˜ω′p</span>, together with known fundamental constants, determines <span tabindex="0">aμ(FNAL)=116592040(54)×10−11</span> (0.46 ppm). The result is 3.3 standard deviations greater than the standard model prediction and is in excellent agreement with the previous Brookhaven National Laboratory (BNL) E821 measurement. After combination with previous measurements of both <span tabindex="0">μ+</span> and <span tabindex="0">μ−</span>, the new experimental average of <span tabindex="0">aμ(Exp)=116592061(41)×10−11</span> (0.35 ppm) increases the tension between experiment and theory to 4.2 standard deviations.</p>
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