We first report an axion haloscope search with toroidal geometry. In this pioneering search, we exclude the axion-photon coupling gaγγ down to about 5×10−8 GeV−1 over the axion mass range from 24.7 ...to 29.1 μeV at a 95% confidence level. The prospects for axion dark matter searches with larger scale toroidal geometry are also considered.
We review the electro-magnetic energy at axion haloscopes and find that the electric and the corresponding magnetic energy stored in the cavity modes or, equivalently, the mode dependent electric and ...magnetic form factors are the same regardless of the position of the cavity inside the solenoid. Furthermore, we extend our argument to the cases satisfying ∇→×B→external=0, where B→external is a static magnetic field provided by a magnet at an axion haloscope. Two typical magnets, solenoidal and toroidal, satisfy ∇→×B→external=0; thus, the electric and the corresponding magnetic energy stored in the cavity modes are always the same in both cases. The energy, however, is independent of the position of the cavity in axion haloscopes with a solenoid, and depends on those with a toroidal magnet.
We report a new measurement of electron antineutrino disappearance using the fully constructed Daya Bay Reactor Neutrino Experiment. The final two of eight antineutrino detectors were installed in ...the summer of 2012. Including the 404 days of data collected from October 2012 to November 2013 resulted in a total exposure of 6.9×10^{5} GW_{th} ton days, a 3.6 times increase over our previous results. Improvements in energy calibration limited variations between detectors to 0.2%. Removal of six ^{241}Am-^{13}C radioactive calibration sources reduced the background by a factor of 2 for the detectors in the experimental hall furthest from the reactors. Direct prediction of the antineutrino signal in the far detectors based on the measurements in the near detectors explicitly minimized the dependence of the measurement on models of reactor antineutrino emission. The uncertainties in our estimates of sin^{2}2θ_{13} and |Δm_{ee}^{2}| were halved as a result of these improvements. An analysis of the relative antineutrino rates and energy spectra between detectors gave sin^{2}2θ_{13}=0.084±0.005 and |Δm_{ee}^{2}|=(2.42±0.11)×10^{-3} eV^{2} in the three-neutrino framework.
We present measurements of e+e- production at midrapidity in Au+Au collisions at sNN=200 GeV. The invariant yield is studied within the PHENIX detector acceptance over a wide range of mass (mee<5 ...GeV/c2) and pair transverse momentum (pT<5 GeV/c) for minimum bias and for five centrality classes. The e+e- yield is compared to the expectations from known sources. In the low-mass region (mee=0.30-0.76 GeV/c2) there is an enhancement that increases with centrality and is distributed over the entire pair pT range measured. It is significantly smaller than previously reported by the PHENIX experiment and amounts to 2.3±0.4(stat)±0.4(syst)±0.2(model) or to 1.7±0.3(stat)±0.3(syst)±0.2(model) for minimum bias collisions when the open heavy-flavor contribution is calculated with pythia or mc@nlo, respectively. The inclusive mass and pT distributions, as well as the centrality dependence, are well reproduced by model calculations where the enhancement mainly originates from the melting of the ρ meson resonance as the system approaches chiral symmetry restoration. In the intermediate-mass region (mee=1.2-2.8 GeV/c2), the data hint at a significant contribution in addition to the yield from the semileptonic decays of heavy-flavor mesons.
We present azimuthal angular correlations between charged hadrons and energy deposited in calorimeter towers in central d+Au and minimum bias p+p collisions at sqrts_{NN}=200 GeV. The charged hadron ...is measured at midrapidity |η|<0.35, and the energy is measured at large rapidity (-3.7<η<-3.1, Au-going direction). An enhanced near-side angular correlation across |Δη|>2.75 is observed in d+Au collisions. Using the event plane method applied to the Au-going energy distribution, we extract the anisotropy strength v_{2} for inclusive charged hadrons at midrapidity up to p_{T}=4.5 GeV/c. We also present the measurement of v_{2} for identified π^{±} and (anti)protons in central d+Au collisions, and observe a mass-ordering pattern similar to that seen in heavy-ion collisions. These results are compared with viscous hydrodynamic calculations and measurements from p+Pb at sqrts_{NN}=5.02 TeV. The magnitude of the mass ordering in d+Au is found to be smaller than that in p+Pb collisions, which may indicate smaller radial flow in lower energy d+Au collisions.
Charged-pion-interferometry measurements were made with respect to the second- and third-order event plane for Au+Au collisions at sqrts_{NN}=200 GeV. A strong azimuthal-angle dependence of the ...extracted Gaussian-source radii was observed with respect to both the second- and third-order event planes. The results for the second-order dependence indicate that the initial eccentricity is reduced during the medium evolution, which is consistent with previous results. In contrast, the results for the third-order dependence indicate that the initial triangular shape is significantly reduced and potentially reversed by the end of the medium evolution, and that the third-order oscillations are largely dominated by the dynamical effects from triangular flow.
The double differential multiplicities and rapidity distributions for Λ hyperon production in central Au + Au interactions at AGS in the range of rapidities from 1.7 to 3.2 GeV and the range of ...transverse kinetic energies from 0.0 to 0.7 GeV are parametrized in terms of the Blast Wave approximation. The longitudinal and transverse radial expansion parameters and the mean temperature of Λ hyperons after the freeze-out of the nuclear matter are presented. The predictions of the RQMD model with and without mean field potentials are compared to our data. Both variants of RQMD are parameterized in terms of the Blast Wave model and the results of such parameterizations are compared to the experimental ones. It is found that inclusion of the repulsive mean field potentials in RQMD is essential to account for the strong expansion observed in the data.
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