Bulletin of the American Physical Society
2013 Annual Fall Meeting of the APS Ohio-Region Section
Volume 58, Number 9
Friday–Saturday, October 4–5, 2013; Cincinnati, Ohio
Session E3: Astrophysics, Gravitation, High Energy |
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Room: Braunstein Hall 309 |
Saturday, October 5, 2013 8:00AM - 8:12AM |
E3.00001: Gravitational Field Equations and Theory of Dark Matter and Dark Energy Tian Ma, Shouhong Wang The main objective of this talk is to derive new gravitational field equations and to establish a unified theory for dark energy and dark matter. The gravitational field equations with a scalar potential $\varphi$ function are the Euler-Lagrangian equations of the classical Einstein-Hilbert functional subject to energy-momentum conservation constraint. From quantum field theoretic point of view, the vector field $\Phi_\mu=D_\mu \varphi$, the gradient of the scalar function $\varphi$, is a spin-1 massless bosonic particle field. The field equations induce a natural duality between the graviton (spin-2 massless bosonic particle) and this spin-1 massless bosonic particle. Both particles can be considered as gravitational force carriers, and as they are massless, the induced forces are long-range forces. The (nonlinear) interaction between these bosonic particle fields leads to a unified theory for dark energy and dark matter. [Preview Abstract] |
Saturday, October 5, 2013 8:12AM - 8:24AM |
E3.00002: Lyman-$\alpha$ Forest Constraints on Decaying Dark Matter and Implications for Galactic Substructure Properties Mei-Yu Wang, Rupert Croft, Annika Peter, Andrew Zentner, Chris Purcell I present an analysis of high-resolution N-body simulations of decaying dark matter (DDM) cosmologies which focuses on the statistical properties of the transmitted Lyman-$\alpha$ (Ly$\alpha$) flux in the high-redshift intergalactic medium (IGM). In this type of model, a dark matter particle decays into a slightly less massive stable dark matter particle and a massless particle. The small mass splitting will provide a non-relativistic kick velocity $V_k$ to the daughter particle and result in free-streaming effect. I especially focus on late decay scenario with decay lifetime around the order of the age of the Universe. I present new limits on unstable dark matter models using current Ly$\alpha$ forest data sets combined with the WMAP7 data. I also use zoom-in numerical simulations to explore the ability of DDM models to solve the small scale problem in galactic halos. I have found that these particular DDM models may provide a solution to both the Galactic subhalo abundance and core/cusp problems, and also that they are consistent with current Ly$\alpha$ limits. [Preview Abstract] |
Saturday, October 5, 2013 8:24AM - 8:36AM |
E3.00003: Probing Growth of Cosmic Structure Using Galaxy Dynamics: A Converging Picture of Velocity Bias Hao-Yi Wu, Dragan Huteter, August Evrard The dynamics of galaxies observed by redshift surveys reflects the gravitation potential of collapsed structure in the Universe, thus providing a sensitive probe of growth of structure and dark energy. To interpret the survey results, numerical simulations are commonly employed; however, these simulations do not always provide realistic galaxy properties due to our limited understanding of baryon physics. In this talk, I will first discuss the impact of uncertainties in simulations on the cosmological results and show that the velocity bias -- the fact that galaxies could have different velocities from dark matter -- can be a dominating source of systematic error. I will then present a study of the velocity bias of cluster galaxies using both N-body and hydrodynamical simulations. I will demonstrate how different physical processes can result in different dynamic properties of galaxy tracers, and and how a consistent picture emerges using state-of-the-art methods for tracking galaxy dynamics. [Preview Abstract] |
Saturday, October 5, 2013 8:36AM - 8:48AM |
E3.00004: Excluding Dark Matter and Dark Energy Hypotheses Wayne Lundberg Dark Matter is a particulate hypothesis to explain gravitational anomalies. Such astrophysical anomalies include gravitational lenses at cluster and super-cluster scales, galactic evolution and dwarf satellite galaxy dispersion, non-Newtonian rotation curves and large-scale structure. There is no reason to expect that one hypothesis will explain all anomalous observations. Non-luminous standard molecular gas explains intergalactic medium and galactic evolution. Recent success of MOdified Newtonian Gravity also explains dwarf satellite galaxy dispersion. These results combine with particle physics experiments to severely constrain DM, particularly SUSY and WIMPs. Dark Energy is a popular hypothesis to explain acceleration of the expansion of the universe. DE competes with the cosmological constant and related models of large-scale structure formation. Recent studies of proton-electron mass ratio severely constrain DE hypotheses. Furthermore, DE requires reformulation of well-established physics to recreate mathematical consistency. The cosmological constant is included in formulations consistent with the no-boundary cosmological condition and its no-boundary wave function. The NBWF is mathematically consistent with a proposed causal reformulation of the standard particle model. Thus DM and DE are nearly excluded. A well-founded and self-consistent theory is presented to better explain all current observations. [Preview Abstract] |
Saturday, October 5, 2013 8:48AM - 9:00AM |
E3.00005: Higgs properties from Higgs to gamma gamma with converted photons Fady Bishara, Yuval Grossman, Roni Harnik, Dean Robinson, Jing Shu, Jure Zupan We show that the photon polarizations in the $h \rightarrow\gamma\gamma$ decay can be used to extract information about the CP properties of the Higgs interactions. The Higgs to photons coupling is one-loop suppressed in the Standard Model (SM) and is a good place to test for New Physics (NP) for two reasons: first, NP that modifies the couplings of the Higgs to vector bosons will have a larger effect on the $h \rightarrow\gamma\gamma$ than the $h\rightarrow Z Z$ coupling which is tree-level in the SM. Second, in the differential decay rate, CP violating observables are linearly proportional to interference terms that vanish in the total rate. In the $h \rightarrow\gamma\gamma$ process, both photons convert via a Bethe-Heitler process in 25\% of the events. For vector bosons in general, the decay plane is itself correlated with the boson polarization. We construct observables sensitive to the CP violating terms in the decay process and present differential distributions from simulated events. [Preview Abstract] |
Saturday, October 5, 2013 9:00AM - 9:12AM |
E3.00006: Tests of Lorentz and CPT symmetry using two-fermion atoms Arnaldo Vargas, V. Alan Kostelecky Lorentz and CPT symmetry are foundational properties of both Special and General Relativity and are key features of our best existing physical theories. Tiny deviations from exact symmetry offer potential signals from the expected unified theory combining quantum physics and gravity. In this talk, I will discuss the prospects for studying signals for Lorentz and CPT violation using spectroscopic experiments with two-fermion atoms. [Preview Abstract] |
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