2,234 research outputs found

    The structure of f(R)f(R)-brane model

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    Recently, a family of interesting analytical brane solutions were found in f(R)f(R) gravity with f(R)=R+αR2f(R)=R+\alpha R^2 in Ref. [Phys. Lett. B 729, 127 (2014)]. In these solutions, inner brane structure can be turned on by tuning the value of the parameter α\alpha. In this paper, we investigate how the parameter α\alpha affects the localization and the quasilocalization of the tensorial gravitons around these solutions. It is found that, in a range of α\alpha, despite the brane has an inner structure, there is no graviton resonance. However, in some other regions of the parameter space, although the brane has no internal structure, the effective potential for the graviton KK modes has a singular structure, and there exists a series of graviton resonant modes. The contribution of the massive graviton KK modes to the Newton's law of gravity is discussed shortly.Comment: v2: 10 pages, 8 figures, to be published in EPJ

    New generalizations of Browder's variational inequalities and the Ky Fan minimax inequality

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    AbstractIn the present paper, some new generalized versions of Browder's theorems for variational inequalities and the Ky Fan minimax inequality are obtained

    Search for C=+C=+ charmonium and XYZ states in e+e−→γ+He^+e^-\to \gamma+ H at BESIII

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    Within the framework of nonrelativistic quantum chromodynamics, we study the production of C=+C=+ charmonium states HH in e+e−→γ + He^+e^-\to \gamma~+~H at BESIII with H=ηc(nS)H=\eta_c(nS) (n=1, 2, 3, and 4), χcJ(nP)\chi_{cJ}(nP) (n=1, 2, and 3), and 1D2(nD)^1D_2(nD) (n=1 and 2). The radiative and relativistic corrections are calculated to next-to-leading order for SS and PP wave states. We then argue that the search for C=+C=+ XYZXYZ states such as X(3872)X(3872), X(3940)X(3940), X(4160)X(4160), and X(4350)X(4350) in e+e−→γ + He^+e^-\to \gamma~+~H at BESIII may help clarify the nature of these states. BESIII can search XYZXYZ states through two body process e+e−→γHe^+e^-\to \gamma H, where HH decay to J/ψπ+π−J/\psi \pi^+\pi^-, J/ψϕJ/\psi \phi, or DDˉD \bar D. This result may be useful in identifying the nature of C=+C=+ XYZXYZ states. For completeness, the production of C=+C=+ charmonium in e+e−→γ+ He^+e^-\to \gamma +~H at B factories is also discussed.Comment: Comments and suggestions are welcome. References are update

    Revealing A Head-on Major Merger in the Nearby NGC 6338 Group with Chandra and VLA observations

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    By analyzing the Chandra archival data of the nearby NGC 6338 galaxy group, we identify two X-ray bright clumps (N-clump and S-clump) within the central 100 kpc, and detect an arc-like X-ray brightness discontinuity at the south boundary of the N-clump, which is defined as a cold front with a gas flow Mach number of M<0.8. Furthermore, at the north-east boundary of the S-clump (dominated by galaxy NGC 6338) another X-ray edge is detected that corresponds to a weaker cold front. Therefore, the two clumps are approaching each other approximately from opposite directions, and the group is undergoing a head-on collision that is in a stage of pre-core passage. This merger scenario is also supported by the study of the line-of-sight velocity distribution of the group member galaxies. The merger mass ratio is about 1:1.8 as estimated from the central gas temperature of the two clumps, which suggests the merger is most likely to be a major merger. We also analyze the VLA 1.4 and 4.9 GHz radio data, but we do not detect any extended radio emission that is associated with the merger.Comment: Accepted by Ap
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