0000000001301035
AUTHOR
Xiaoping Wang
showing 17 related works from this author
Chiral Organometallic Triangles with Rh−Rh Bonds. 2. Compounds Prepared from Enantiopure cis-Rh2(C6H4PPh2)2(OAc)2(HOAc)2 and Their Catalytic Potentia…
2005
Enantiomers of the orthometalated dirhodium compound cis-Rh2(C6H4PPh2)2(OAc)2(HOAc)2 (R-1 and S-1) were prepared from carboxylate exchange reactions of the resolved diasteroisomers of cis-Rh2(C6H4PPh2)2(protos)2(H2O)2 (protos = N-4-methylphenylsulfonyl-l-proline anion) and acetic acid. These compounds react with excess Me3OBF4 in CH3CN, producing the enantiomers of [cis-Rh2(C6H4PPh2)2(CH3CN)6](BF4)2 (R-2 and S-2) which have six labile and replaceable CH3CN ligands in equatorial and axial positions. Reactions of R-2 and S-2 with tetraethylammonium salts of the linear dicarboxylic acids, terephthalic acid (HO2CC6H4CO2H), oxalic acid (HO2CCO2H), and 4,4'-diphenyl-dicarboxylic acid (HO2CC6H4C6H…
Impeded Dark Matter
2016
We consider dark matter models in which the mass splitting between the dark matter particles and their annihilation products is tiny. Compared to the previously proposed Forbidden Dark Matter scenario, the mass splittings we consider are much smaller, and are allowed to be either positive or negative. To emphasize this modification, we dub our scenario "Impeded Dark Matter". We demonstrate that Impeded Dark Matter can be easily realized without requiring tuning of model parameters. For negative mass splitting, we demonstrate that the annihilation cross-section for Impeded Dark Matter depends linearly on the dark matter velocity or may even be kinematically forbidden, making this scenario al…
Sterile neutrinos and flavor ratios in IceCube
2017
The flavor composition of astrophysical neutrinos observed in neutrino telescopes is a powerful discriminator between different astrophysical neutrino production mechanisms and can also teach us about the particle physics properties of neutrinos. In this paper, we investigate how the possible existence of light sterile neutrinos can affect these flavor ratios. We consider two scenarios: (i) neutrino production in conventional astrophysical sources, followed by partial oscillation into sterile states; (ii) neutrinos from dark matter decay with a primary flavor composition enhanced in tau neutrinos or sterile neutrinos. Throughout the paper, we constrain the sterile neutrino mixing parameters…
X-Ray Lines from Dark Matter Annihilation at the keV Scale.
2018
In 2014, several groups reported hints for a yet unidentified line in astrophysical x-ray signals from galaxies and galaxy clusters at an energy of 3.5 keV. While it is not unlikely that this line is simply a reflection of imperfectly modeled atomic transitions, it has renewed the community’s interest in models of keV-scale dark matter, whose decay would lead to such a line. The alternative possibility of dark matter annihilation into monochromatic photons is far less explored, a lapse that we strive to amend in this Letter. More precisely, we introduce a novel model of fermionic dark matter χ with O(keV) mass, annihilating to a scalar state ϕ which in turn decays to photons, for instance v…
The coannihilation codex
2015
We present a general classification of simplified models that lead to dark matter (DM) coannihilation processes of the form DM + X $\rightarrow$ SM$_1$ + SM$_2$, where X is a coannihilation partner for the DM particle and SM$_1$, SM$_2$ are Standard Model fields. Our classification also encompasses regular DM pair annihilation scenarios if DM and X are identical. Each coannhilation scenario motivates the introduction of a mediating particle M that can either belong to the Standard Model or be a new field, whereby the resulting interactions between the dark sector and the Standard Model are realized as tree-level and dimension-four couplings. We construct a basis of coannihilation models, cl…
Exposing the dark sector with future Z factories
2017
We investigate the prospects of searching dark sector models via exotic Z-boson decay at future e⁺e⁻ colliders with Giga Z and Tera Z options. Four general categories of dark sector models, Higgs portal dark matter, vector-portal dark matter, inelastic dark matter, and axionlike particles, are considered. Focusing on channels motivated by the dark sector models, we carry out a model-independent study of the sensitivities of Z factories in probing exotic decays. The limits on branching ratios of the exotic Z decay are typically O(10⁻⁶–10⁻[superscript 8.5]) for the Giga Z and O(10⁻[superscript 7.5]–10⁻¹¹) for the Tera Z, and they are compared with the projection for the high luminosity LHC. W…
A tale of two portals: testing light, hidden new physics at future e + e − colliders
2017
We investigate the prospects for producing new, light, hidden states at a future $e^+ e^-$ collider in a Higgsed dark $U(1)_D$ model, which we call the Double Dark Portal model. The simultaneous presence of both vector and scalar portal couplings immediately modifies the Standard Model Higgsstrahlung channel, $e^+ e^- \to Zh$, at leading order in each coupling. In addition, each portal leads to complementary signals which can be probed at direct and indirect detection dark matter experiments. After accounting for current constraints from LEP and LHC, we demonstrate that a future $e^+ e^-$ Higgs factory will have unique and leading sensitivity to the two portal couplings by studying a host o…
CCDC 291814: Experimental Crystal Structure Determination
2006
Related Article: F.A.Cotton, C.A.Murillo, S.-E.Stiriba, Xiaoping Wang, Rongmin Yu|2005|Inorg.Chem.|44|8223|doi:10.1021/ic051282c
CCDC 291816: Experimental Crystal Structure Determination
2006
Related Article: F.A.Cotton, C.A.Murillo, S.-E.Stiriba, Xiaoping Wang, Rongmin Yu|2005|Inorg.Chem.|44|8223|doi:10.1021/ic051282c
CCDC 291817: Experimental Crystal Structure Determination
2006
Related Article: F.A.Cotton, C.A.Murillo, S.-E.Stiriba, Xiaoping Wang, Rongmin Yu|2005|Inorg.Chem.|44|8223|doi:10.1021/ic051282c
CCDC 291810: Experimental Crystal Structure Determination
2006
Related Article: F.A.Cotton, C.A.Murillo, S.-E.Stiriba, Xiaoping Wang, Rongmin Yu|2005|Inorg.Chem.|44|8223|doi:10.1021/ic051282c
CCDC 291813: Experimental Crystal Structure Determination
2006
Related Article: F.A.Cotton, C.A.Murillo, S.-E.Stiriba, Xiaoping Wang, Rongmin Yu|2005|Inorg.Chem.|44|8223|doi:10.1021/ic051282c
CCDC 291818: Experimental Crystal Structure Determination
2006
Related Article: F.A.Cotton, C.A.Murillo, S.-E.Stiriba, Xiaoping Wang, Rongmin Yu|2005|Inorg.Chem.|44|8223|doi:10.1021/ic051282c
CCDC 291809: Experimental Crystal Structure Determination
2006
Related Article: F.A.Cotton, C.A.Murillo, S.-E.Stiriba, Xiaoping Wang, Rongmin Yu|2005|Inorg.Chem.|44|8223|doi:10.1021/ic051282c
CCDC 291811: Experimental Crystal Structure Determination
2006
Related Article: F.A.Cotton, C.A.Murillo, S.-E.Stiriba, Xiaoping Wang, Rongmin Yu|2005|Inorg.Chem.|44|8223|doi:10.1021/ic051282c
CCDC 291812: Experimental Crystal Structure Determination
2006
Related Article: F.A.Cotton, C.A.Murillo, S.-E.Stiriba, Xiaoping Wang, Rongmin Yu|2005|Inorg.Chem.|44|8223|doi:10.1021/ic051282c
CCDC 291815: Experimental Crystal Structure Determination
2006
Related Article: F.A.Cotton, C.A.Murillo, S.-E.Stiriba, Xiaoping Wang, Rongmin Yu|2005|Inorg.Chem.|44|8223|doi:10.1021/ic051282c