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Differential elliptic flow (v(2)) for phi mesons and (anti)deuterons (d)d is measured for Au+Au collisions at square root of sNN=200 GeV. The v(2) for phi mesons follows the trend of lighter pi+/- and K+/- mesons, suggesting that ordinary hadrons interacting with standard hadronic cross sections are not the primary driver for elliptic flow development. The v(2) values for (d)d suggest that elliptic flow is additive for composite particles. This further validation of the universal scaling of v(2) per constituent quark for baryons and mesons suggests that partonic collectivity dominates the transverse expansion dynamics.

163The standard model (SM) of particle physics is spectacularly successful, yet the measured value 164 of the muon anomalous magnetic moment (g − 2)µ deviates from SM calculations by 3.6σ. Several 165 theoretical models attribute this to the existence of a "dark photon," an additional U(1) gauge 166 boson, which is weakly coupled to ordinary photons. The PHENIX experiment at the Relativistic 167Heavy Ion Collider has searched for a dark photon, U , in π 0 , η → γe + e − decays and obtained 168upper limits of O(2 × 10 −6 ) on U -γ mixing at 90% CL for the mass range 30 < mU < 90 MeV/c 2 . 169Combined with other experimental limits, the remaining region in the U -γ mixing parameter space 170 that can explain the (g − 2)µ deviation from its SM value is nearly completely excluded at the 90% 184While a variety of mechanisms can be introduced to parameterize dark sector physics, a simple formulation pos- 185tulates a "dark photon" of mass m U which mixes with QED photons via a "kinetic coupling" term in the La-186 grangian [7, 8, 17, 18] 187where ε parametrizes the mixing strength. N 2γ is the invariant yield of 2γ decays of π 0 , η, α EM is the fine structure constant, and m e , m π 0 ,η are masses for From the peak height ratio,the dark photon mixing parameter can then be determined as:Note that in this approach the efficiencies for detection of e + e − pairs from Dalitz decays and from dark photons 209 cancel in the ratio R(m U ).The analysis presented here is based on a precise measurement of virtual photons from π 0 and η Dalitz decays [21] 211 across three PHENIX data sets at a collision energy of √ s N N = 200 GeV with an integrated luminosity of 4.8 pb correlations are evaluated using like-sign pairs. After scaling by the number of nucleon-nucleon collisions, the correlated 231 backgrounds in p+p and d+Au are very similar, indicating these background contributions are well understood. Pairs

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We report a measurement of e + e − pairs from semileptonic heavy-flavor decays in p+p collisions at √ s N N = 200 GeV. The e + e − pair yield from bb and cc is separated by exploiting a double differential fit done simultaneously in dielectron invariant mass and pT. We used three different event generators, pythia, mc@nlo, and powheg, to simulate the e + e − spectra from cc and bb production. The data can be well described by all three generators within the detector acceptance. However, when using the generators to extrapolate to 4π, significant differences are observed for the total cross section. These difference are less pronounced for bb than for cc. The same model dependence was observed in already published d+A data. The p+p data are also directly compared with d+A data in mass and pT , and within the statistical accuracy no nuclear modification is seen.