2,612 research outputs found

    Quantization of Black Holes

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    We show that black holes can be quantized in an intuitive and elegant way with results in agreement with conventional knowledge of black holes by using Bohr's idea of quantizing the motion of an electron inside the atom in quantum mechanics. We find that properties of black holes can be also derived from an Ansatz of quantized entropy \Delta S=4\pi k {\Delta R / \lambdabar}, which was suggested in a previous work to unify the black hole entropy formula and Verlinde's conjecture to explain gravity as an entropic force. Such an Ansatz also explains gravity as an entropic force from quantum effect. This suggests a way to unify gravity with quantum theory. Several interesting and surprising results of black holes are given from which we predict the existence of primordial black holes ranging from Planck scale both in size and energy to big ones in size but with low energy behaviors.Comment: Latex 7 pages, no figure

    Isospin violation in Ο•,J/ψ,Οˆβ€²β†’Ο‰Ο€0\phi, J/\psi, \psi^\prime \to \omega \pi^0 via hadronic loops

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    In this work, we study the isospin-violating decay of ϕ→ωπ0\phi\to \omega\pi^0 and quantify the electromagnetic (EM) transitions and intermediate meson exchanges as two major sources of the decay mechanisms. In the EM decays, the present datum status allows a good constraint on the EM decay form factor in the vector meson dominance (VMD) model, and it turns out that the EM transition can only account for about 1/4∼1/31/4\sim 1/3 of the branching ratio for ϕ→ωπ0\phi\to \omega\pi^0. The intermediate meson exchanges, KKΛ‰(Kβˆ—)K\bar{K}(K^*) (intermediate KKΛ‰K\bar{K} interaction via Kβˆ—K^* exchanges), KKβˆ—Λ‰(K)K\bar{K^*}(K) (intermediate KKβˆ—Λ‰K\bar{K^*} rescattering via kaon exchanges), and KKβˆ—Λ‰(Kβˆ—)K\bar{K^*}(K^*) (intermediate KKβˆ—Λ‰K\bar{K^*} rescattering via Kβˆ—K^* exchanges), which evade the naive Okubo-Zweig-Iizuka (OZI) rule, serve as another important contribution to the isospin violations. They are evaluated with effective Lagrangians where explicit constraints from experiment can be applied. Combining these three contributions, we obtain results in good agreement with the experimental data. This approach is also extended to J/ψ(Οˆβ€²)→ωπ0J/\psi(\psi^\prime)\to \omega\pi^0, where we find contributions from the KKΛ‰(Kβˆ—)K\bar{K}(K^*), KKβˆ—Λ‰(K)K\bar{K^*}(K) and KKβˆ—Λ‰(Kβˆ—)K\bar{K^*}(K^*) loops are negligibly small, and the isospin violation is likely to be dominated by the EM transition.Comment: Revised version resubmitted to PRD; Additional loop contributions included; Conclusion unchange

    Probing scalar meson structures in Ο‡c1\chi_{c1} decays into pseudoscalar and scalar

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    We evaluate the decay branching ratios of χc1→PS\chi_{c1}\to PS, in a quark model parametrization scheme, where PP and SS stand for pseudoscalar and scalar meson, respectively. An interesting feature of this decay process is that the ccˉc\bar{c} annihilate via the pQCD hair-pin diagram is supposed to be dominant. Hence, this decay process should be sensitive to the quark components of the final-state light mesons, and would provide a great opportunity for testing the mixing relations among the scalar mesons, i.e. f0(1370)f_0(1370), f0(1500)f_0(1500) and f0(1710)f_0(1710), by tagging the final state pseudoscalar mesons.Comment: 9 pages and 6 eps figures; Enhanced discussion on the dominance of hair-pin diagram is added. Revised version to appear in IJMP

    Holographic Schwinger effect with a moving D3-brane

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    We study the Schwinger effect with a moving D3-brane in a N\mathcal{N}=4 SYM plasma with the aid of AdS/CFT correspondence. We discuss the test particle pair moving transverse and parallel to the plasma wind respectively. It is found that for both cases the presence of velocity tends to increase the Schwinger effect. In addition, the velocity has a stronger influence on the Schwinger effect when the pair moves transverse to the plasma wind rather than parallel.Comment: 8 pages, 6 figure

    2-[4-(DimethylΒ­amino)phenΒ­yl]imidazo[4,5-f][1,10]phenanthroline sesquihydrate

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    There are two formula units in the asymmetric unit of the title compound, C21H17N5Β·1.5H2O. The imidazo[4,5-f][1,10]phenΒ­anΒ­throline unit is almost coplanar with the benzene ring, the dihedral angles between them being 8.91β€…(5) and 4.93β€…(6)Β° in the two molΒ­ecules. The crystal structure is stabilized by a series of hydrogen bonds between the water molΒ­ecules and the N atoms of the imidazophenanthroline groups

    Probing the nature of Y(4260)Y(4260) and Zc(3900)Z_c(3900) in the isospin violating process Y(4260)β†’J/ΟˆΞ·Ο€0Y(4260) \to J/\psi \eta \pi^0

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    The isospin violation process Y(4260)β†’J/ΟˆΞ·Ο€0Y(4260) \to J/\psi \eta \pi^{0} is studied assuming that Y(4260)Y(4260) is a D1DΛ‰+c.c.D_{1} \bar{D}+c.c. hadronic molecule. In association with the production of the Zc(3900)Z_c(3900), which is treated as a DDΛ‰βˆ—+c.c.D \bar{D}^{*}+c.c. hadronic molecule, this process can help us distinguish their molecular natures from other scenarios, since the incomplete cancellation between the charged and neutral--meson loops, which are prominent in the molecular picture only, produces a peak in the e+eβˆ’β†’Y(4260)β†’J/ΟˆΞ·Ο€0e^+e^-\to Y(4260)\to J/\psi\eta\pi^0 cross section at the D1DΛ‰+c.c.D_{1} \bar{D}+c.c. threshold and a very prominent peak in the J/ψηJ/\psi \eta invariant mass spectrum in between the DDΛ‰βˆ—+c.c.D \bar{D}^{*}+c.c. thresholds; the latter being much narrower than the corresponding one in the isospin conserving channel, i.e. J/ΟˆΟ€+Ο€βˆ’J/\psi \pi^+ \pi^{-}. The partial width of Y(4260)β†’J/ΟˆΞ·Ο€0Y(4260)\to J/\psi\eta\pi^0 is about 4Γ—10βˆ’44 \times 10^{-4} of that of Y(4260)β†’J/ΟˆΟ€+Ο€βˆ’Y(4260)\to J/\psi\pi^+\pi^-. The cross section of e+eβˆ’β†’Y(4260)β†’J/ΟˆΞ·Ο€0e^+e^-\to Y(4260)\to J/\psi\eta\pi^0 at the D1DΛ‰+c.c.D_{1} \bar{D}+c.c. threshold is about 0.05Β pb0.05 \ \mathrm{pb} which is much larger than that produced by the nearby resonances. These features are the direct consequences of the assumed nature of these two states which might be accessible at the high-statistics experiments such as BESIII and LHCb.Comment: 11 pages, 4 figure

    Further understanding of the non-DDΛ‰D\bar D decays of ψ(3770)\psi(3770)

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    We provide details of the study of ψ(3770)\psi(3770) non-DDΛ‰D\bar D decays into VPVP, where VV and PP denote light vector meson and pseudoscalar meson, respectively. We find that the electromagnetic (EM) interaction plays little role in these processes, while the strong interaction dominates. The strong interaction can be separated into two parts, i.e. the short-distance part probing the wave function at origin and the long-distance part reflecting the soft gluon exchanged dynamics. The long-distance part is thus described by the intermediate charmed meson loops. We show that the transition of ψ(3770)β†’VP\psi(3770)\to VP can be related to ψ(3686)β†’VP\psi(3686)\to VP such that the parameters in our model can be constrained by comparing the different parts in ψ(3770)β†’VP\psi(3770)\to VP to those in ψ(3686)β†’VP\psi(3686)\to VP. Our quantitative results confirm the findings of [Zhang {\it et al.}, Phys. Rev. Lett. 102, 172001 (2009)] that the OZI-rule-evading long-distance strong interaction via the IML plays an important role in ψ(3770)\psi(3770) decays, and could be a key towards a full understanding of the mysterious ψ(3770)\psi(3770) non-DDΛ‰D\bar{D} decay mechanism.Comment: 11 pages, 4 figures, version to appear in Phys. Rev.
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