The main goal of the future MPD experiment at NICA is to explore the QCD phase diagram in the region of highly compressed and hot baryonic matter in the energy range corresponding to the highest chemical potential. Properties of such dense matter can be studied using azimuthal anisotropy which is categorized by the Fourier coefficients of the azimuthal distribution decomposition. Performance of the detector response based on simulations with realistic reconstruction procedure is presented for centrality determination, reaction plane estimation, directed and elliptic flow coefficients.
The anisotropic collective flow is one of the key observables to study the properties of dense matter created in heavy-ion collisions. The performance of Multi-Purpose Detector (MPD) at NICA collider for directed and elliptic flow measurements is studied with Monte-Carlo simulations of heavy-ion collisions at energies $sqrt{s_{NN}}$ = 4 - 11 GeV.
The Fermi National Accelerator Laboratory has measured the anomalous precession frequency $a^{}_mu = (g^{}_mu-2)/2$ of the muon to a combined precision of 0.46 parts per million with data collected during its first physics run in 2018. This paper documents the measurement of the magnetic field in the muon storage ring. The magnetic field is monitored by nuclear magnetic resonance systems and calibrated in terms of the equivalent proton spin precession frequency in a spherical water sample at 34.7$^circ$C. The measured field is weighted by the muon distribution resulting in $tilde{omega}^{}_p$, the denominator in the ratio $omega^{}_a$/$tilde{omega}^{}_p$ that together with known fundamental constants yields $a^{}_mu$. The reported uncertainty on $tilde{omega}^{}_p$ for the Run-1 data set is 114 ppb consisting of uncertainty contributions from frequency extraction, calibration, mapping, tracking, and averaging of 56 ppb, and contributions from fast transient fields of 99 ppb.
The Muon g-2 Experiment at Fermi National Accelerator Laboratory (FNAL) has measured the muon anomalous precession frequency $omega_a$ to an uncertainty of 434 parts per billion (ppb), statistical, and 56 ppb, systematic, with data collected in four storage ring configurations during its first physics run in 2018. When combined with a precision measurement of the magnetic field of the experiments muon storage ring, the precession frequency measurement determines a muon magnetic anomaly of $a_{mu}({rm FNAL}) = 116,592,040(54) times 10^{-11}$ (0.46 ppm). This article describes the multiple techniques employed in the reconstruction, analysis and fitting of the data to measure the precession frequency. It also presents the averaging of the results from the eleven separate determinations of omega_a, and the systematic uncertainties on the result.
A precise measurement of the vector and axial-vector form factors difference $F_V-F_A$ in the $K^+rightarrow{mu^+}{ u_{mu}}{gamma}$ decay is presented. About 95K events of $K^+rightarrow{mu^+}{ u_{mu}}{gamma}$ are selected in the OKA experiment. The result is $F_V-F_A=0.134pm0.021(stat)pm0.027(syst)$. Both errors are smaller than in the previous $F_V-F_A$ measurements.
A measurement of electron antineutrino oscillation by the Daya Bay Reactor Neutrino Experiment is described in detail. Six 2.9-GW$_{rm th}$ nuclear power reactors of the Daya Bay and Ling Ao nuclear power facilities served as intense sources of $overline{ u}_{e}$s. Comparison of the $overline{ u}_{e}$ rate and energy spectrum measured by antineutrino detectors far from the nuclear reactors ($sim$1500-1950 m) relative to detectors near the reactors ($sim$350-600 m) allowed a precise measurement of $overline{ u}_{e}$ disappearance. More than 2.5 million $overline{ u}_{e}$ inverse beta decay interactions were observed, based on the combination of 217 days of operation of six antineutrino detectors (Dec. 2011--Jul. 2012) with a subsequent 1013 days using the complete configuration of eight detectors (Oct. 2012--Jul. 2015). The $overline{ u}_{e}$ rate observed at the far detectors relative to the near detectors showed a significant deficit, $R=0.949 pm 0.002(mathrm{stat.}) pm 0.002(mathrm{syst.})$. The energy dependence of $overline{ u}_{e}$ disappearance showed the distinct variation predicted by neutrino oscillation. Analysis using an approximation for the three-flavor oscillation probability yielded the flavor-mixing angle $sin^22theta_{13}=0.0841 pm 0.0027(mathrm{stat.}) pm 0.0019(mathrm{syst.})$ and the effective neutrino mass-squared difference of $left|{Delta}m^2_{mathrm{ee}}right|=(2.50 pm 0.06(mathrm{stat.}) pm 0.06(mathrm{syst.})) times 10^{-3} {rm eV}^2$. Analysis using the exact three-flavor probability found ${Delta}m^2_{32}=(2.45 pm 0.06(mathrm{stat.}) pm 0.06(mathrm{syst.})) times 10^{-3} {rm eV}^2$ assuming the normal neutrino mass hierarchy and ${Delta}m^2_{32}=(-2.56 pm 0.06(mathrm{stat.}) pm 0.06(mathrm{syst.})) times 10^{-3} {rm eV}^2$ for the inverted hierarchy.