We present a new measurement of the positive muon magnetic anomaly, a µ ≡ (gµ − 2)/2, from the Fermilab Muon g −2 Experiment based on data collected in 2019 and 2020. We have analyzed more than four times the number of positrons from muon decay than in our previous result from 2018 data. The systematic error is reduced by more than a factor of two due to better running conditions, a more stable beam, and improved knowledge of the magnetic field weighted by the muon distribution, ω′ p , and of the anomalous precession frequency corrected for beam dynamics effects, ωa. From the ratio ωa/ω ′ p , together with precisely determined external parameters, we determine a µ = 116 592 057(25) × 10 −11 (0.21 ppm). Combining this result with our previous result from the 2018 data, we obtain a µ (FNAL) = 116 592 055(24) × 10 −11 (0.20 ppm). The new experimental world average is aµ(Exp) = 116 592 059(22) × 10 −11 (0.19 ppm), which represents a factor of two improvement in precision.

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We report observation of the electroweak production of single top quarks in pp collisions at √ s = 1.96 TeV based on 2.3 fb −1 of data collected by the D0 detector at the Fermilab Tevatron Collider. Using events containing an isolated electron or muon and missing transverse energy, together with jets originating from the fragmentation of b quarks, we measure a cross section of σ(pp → tb + X, tqb + X) = 3.94 ± 0.88 pb. The probability to measure a cross section at this value or higher in the absence of signal is 2.5×10 −7 , corresponding to a 5.0 standard deviation significance for the observation.

We perform a combination of searches for standard model Higgs boson production in p p collisions recorded by the D0 detector at the Fermilab Tevatron Collider at a center of mass energy of ffiffi ffi s p ¼ 1:96 TeV. The different production and decay channels have been analyzed separately, with integrated luminosities of up to 9:7 fb À1 and for Higgs boson masses 90 M H 200 GeV. We combine these final states to achieve optimal sensitivity to the production of the Higgs boson. We also interpret the combination in terms of models with a fourth generation of fermions, and models with suppressed Higgs boson couplings to fermions. The result excludes a standard model Higgs boson at 95% C.L. in the ranges 90 < M H < 101 GeV and 157 < M H < 178 GeV, with an expected exclusion of 155 < M H < 175 GeV. In the range 120 < M H < 145 GeV, the data exhibit an excess over the expected background of up to 2 standard deviations, consistent with the presence of a standard model Higgs boson of mass 125 GeV.

We present the first measurement of the D* ϩ width using 9/fb of e ϩ e Ϫ data collected near the ⌼(4S) resonance by the CLEO II.V detector. Our method uses advanced tracking techniques and a reconstruction method that takes advantage of the small vertical size of the CESR beam spot to measure the energy release distribution from the D* ϩ →D 0 ϩ decay. We find ⌫(D* ϩ )ϭ96Ϯ4 (statistical)Ϯ22 (systematic) keV. We also measure the energy release in the decay and compute ⌬mϵm D* ϩϪ m D 0ϭ 145.412Ϯ0.002 (statistical) Ϯ0.012 (systematic) MeV/c 2 .