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We report the beam energy ( √ sNN = 7.7 -200 GeV) and collision centrality dependence of the mean (M ), standard deviation (σ), skewness (S), and kurtosis (κ) of the net-proton multiplicity distributions in Au+Au collisions. The measurements are carried out by the STAR experiment at midrapidity (|y| < 0.5) and within the transverse momentum range 0.4 < pT < 0.8 GeV/c in the first phase of the Beam Energy Scan program at the Relativistic Heavy Ion Collider. These measurements are important for understanding the Quantum Chromodynamic (QCD) phase diagram.

The mass of the W boson, a mediator of the weak force between elementary particles, is tightly constrained by the symmetries of the standard model of particle physics. The Higgs boson was the last missing component of the model. After observation of the Higgs boson, a measurement of the W boson mass provides a stringent test of the model. We measure the W boson mass, M W , using data corresponding to 8.8 inverse femtobarns of integrated luminosity collected in proton-antiproton collisions at a 1.96 tera–electron volt center-of-mass energy with the CDF II detector at the Fermilab Tevatron collider. A sample of approximately 4 million W boson candidates is used to obtain M W = 80 , 433.5 ± 6.4 stat ± 6.9 syst = 80 , 433.5 ± 9.4  MeV / c 2 , the precision of which exceeds that of all previous measurements combined (stat, statistical uncertainty; syst, systematic uncertainty; MeV, mega–electron volts; c , speed of light in a vacuum). This measurement is in significant tension with the standard model expectation.

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We present a new measurement of the inclusive forward-backward tt production asymmetry and its rapidity and mass dependence. The measurements are performed with data corresponding to an integrated luminosity of 5.3 fb −1 of pp collisions at √ s = 1.96 TeV, recorded with the CDF II Detector at the Fermilab Tevatron. Significant inclusive asymmetries are observed in both the laboratory frame and the tt rest frame, and in both cases are found to be consistent with CP conservation under interchange of t andt. In the tt rest frame, the asymmetry is observed to increase with the tt rapidity difference, ∆y, and with the invariant mass M tt of the tt system. Fully corrected parton-level asymmetries are derived in two regions of each variable, and the asymmetry is found to be most significant at large ∆y and M tt . For M tt ≥ 450 GeV/c 2 , the parton-level asymmetry in the tt rest frame is A tt = 0.475 ± 0.114 compared to a next-to-leading order QCD prediction of 0.088 ± 0.013.