On the renormalization of quasi parton distribution

Recent developments showed that light-cone parton distributions can be studied by investigating the large momentum limit of the hadronic matrix elements of spacelike correlators, which are known as quasi parton distributions. Like a light-cone parton distribution, a quasi parton distribution also contains ultraviolet divergences and therefore needs renormalization. The renormalization of non-local operators in general is not well understood. However, in the case of quasi quark distribution, the bilinear quark operator with a straight-line gauge link appears to be multiplicatively renormalizable by the quark wave function renormalization in the axial gauge. We first show that the renormalization of the self energy correction to the quasi quark distribution is equivalent to that of the heavy-light quark vector current in heavy quark effective theory at one-loop order. Assuming this equivalence at two-loop order, we then show that the multiplicative renormalizability of the quasi quark distribution is true at two-loop order.Comment: 14 pages, 4 figure

Radiative Corrections to H0→WW/ZZH^0\to WW/ZZ in the MSSM

The electroweak $\mathcal O(\alpha)$ radiative corrections to the decay of the heavy CP-even MSSM Higgs boson to weak gauge bosons are presented. Due to the suppression of the tree-level $H^0WW/H^0ZZ$ coupling, the electroweak contributions to the partial decay width are significant. Although the effective Born decay width can be rather small for certain $M_{A^0}$ values (especially for large $\tan\beta$), the corrected partial widths at different values of $M_{A^0}$ are of comparable size.Comment: 13 pages, 7 figures, version to appear in PR

Vacuum Stability and Higgs Diphoton Decay Rate in the Zee-Babu Model

Although recent Higgs data from ATLAS and CMS are compatible with a Standard Model (SM) signal at $2\sigma$ level, both experiments see indications for an excess in the diphoton decay channel, which points to new physics beyond the SM. Given such a low Higgs mass $m_H \sim 125 {\rm GeV}$, another sign indicating the existence of new physics beyond the SM is the vacuum stability problem, i.e., the SM Higgs quartic coupling may run to negative values at a scale below the Planck scale. In this paper, we study the vacuum stability and enhanced Higgs diphoton decay rate in the Zee-Babu model, which was used to generate tiny Majorana neutrino masses at two-loop level. We find that it is rather difficult to find overlapping regions allowed by the vacuum stability and diphoton enhancement constraints. As a consequence, it is almost inevitable to introduce new ingredients into the model, in order to resolve these two issues simultaneously.Comment: 19 pages, 6 figure

Gravity/Fluid Correspondence and Its Application on Bulk Gravity with U(1)U(1) Gauge Field

As the long wavelength limit of the AdS/CFT correspondence, the gravity/fluid correspondence has been shown to be a useful tool for extracting properties of the fluid on the boundary dual to the gravity in the bulk. In this paper, after briefly reviewing the algorithm of gravity/fluid correspondence, we discuss the results of its application on bulk gravity with a $U(1)$ gauge field. In the presence of a $U(1)$ gauge field, the dual fluid possesses more interesting properties such as its charge current. Furthermore, an external field $A_\mu^{ext}$ could affect the charge current, and the $U(1)$ Chern-Simons term also reinduces extra structures to the dual current giving anomalous transport coefficients.Comment: 14 pages, no figure, version publishe