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We present the first results of the Fermilab Muon g-2 Experiment for the positive muon magnetic anomaly $a_mu equiv (g_mu-2)/2$. 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 $omega_a$ 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 ${tilde{omega}^{}_p}$ in a spherical water sample at 34.7$^{circ}$C. The ratio $omega_a / {tilde{omega}^{}_p}$, together with known fundamental constants, determines $a_mu({rm FNAL}) = 116,592,040(54)times 10^{-11}$ (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 $mu^+$ and $mu^-$, the new experimental average of $a_mu({rm Exp}) = 116,592,061(41)times 10^{-11}$ (0.35,ppm) increases the tension between experiment and theory to 4.2 standard deviations
The anomalous magnetic moment (g-2) of the muon was measured with a precision of 0.54 ppm in Experiment 821 at Brookhaven National Laboratory. A difference of 3.2 standard deviations between this experimental value and the prediction of the Standard
We report on a precision measurement of the cross section for the reaction $e^+e^-topi^+pi^-$ in the mass range $0.30<M_{pipi}<1.00$ GeV with the initial state radiation (ISR) method, using 817 pb$^{-1}$ of data at $e^+e^-$ center-of-mass energies ne
We present the final report from a series of precision measurements of the muon anomalous magnetic moment, a_mu = (g-2)/2. The details of the experimental method, apparatus, data taking, and analysis are summarized. Data obtained at Brookhaven Nation
We report a measurement of the positive muon lifetime to a precision of 1.0 parts per million (ppm); it is the most precise particle lifetime ever measured. The experiment used a time-structured, low-energy muon beam and a segmented plastic scintilla
The mean life of the positive muon has been measured to a precision of 11 ppm using a low-energy, pulsed muon beam stopped in a ferromagnetic target, which was surrounded by a scintillator detector array. The result, tau_mu = 2.197013(24) us, is in e