Form Factors for Exclusive Semileptonic BB--Decays

We developed the new parton model approach for exclusive semileptonic decays of $B$-meson to $D,~D^*$ by extending the inclusive parton model, and by combining with the results of the HQET, motivated by Drell-Yan process. Without the nearest pole dominance ans\"atze, we {\bf derived} the dependences of hadronic form factors on $q^2$. We also calculated numerically the slope of the Isgur-Wise function, which is consistent with the experimental results.Comment: 20 pages, RevTex, 2 ps figure files(uuencoded in seperate file

Implication of the weak phase β\beta measured in B→ργB \to \rho \gamma decay

We explore the exclusive $B^0 \to \rho^0 \gamma$ decay to obtain the time-dependent CP asymmetry in $b \to d \gamma$ decay process. We find that the complex RL and RR mass insertion to the squark sector in the MSSM can lead to a large deviation of CP asymmetry from that predicted in the Standard Model.Comment: 4 pages, talk given at the 32nd International Conference on High Energy Physics (ICHEP'04), Beijing, China, 16-22 Aug. 200

Singlet Fermionic Dark Matter with Dark ZZ

We present a fermionic dark matter model mediated by the hidden gauge boson. We assume the QED-like hidden sector which consists of a Dirac fermion and U(1)$_X$ gauge symmetry, and introduce an additional scalar electroweak doublet field with the U(1)$_X$ charge as a mediator. The hidden U(1)$_X$ symmetry is spontaneously broken by the electroweak symmetry breaking and there exists a massive extra neutral gauge boson in this model which is the mediator between the hidden and visible sectors. Due to the U(1)$_X$ charge, the additional scalar doublet does not couple to the Standard Model fermions, which leads to the Higgs sector of type I two Higgs doublet model. The new gauge boson couples to the Standard Model fermions with couplings proportional to those of the ordinary $Z$ boson but very suppressed, thus we call it the dark $Z$ boson. We study the phenomenology of the dark $Z$ boson and the Higgs sector, and show the hidden fermion can be the dark matter candidate.Comment: 10 pages, 3 figure

Atypical vitelliform macular dystrophy misdiagnosed as chronic central serous chorioretinopathy: case reports

BACKGROUND: To report two cases of atypical vitelliform macular dystrophy misdiagnosed as chronic central serous chorioretinopathy. CASE PRESENTATION: Two patients with incidentally discovered abnormalities of the retina without specific symptoms were referred to our hospital for consultation. Bilateral macula atrophic lesions were observed and optical coherence tomography revealed serous retinal detachment in the macula. Fluorescein angiography showed multiple leakages around the central hypofluorescent area and indocyanine green angiography showed partially dilated choroidal vessels. Fundus autofluorescence (FAF) showed a decreasing pattern of autofluorescence in the subretinal fluid area, and increasing autofluorescence at the border of the serous retinal detachment. Both patients were diagnosed with chronic central serous chorioretinopathy. Photodynamic therapy and intravitreal bevacizumab injection were administered for engorged choroidal vessels during follow-up, but neither patient showed improvement in symptoms or ophthalmologic findings. Based on re-evaluation by fundus photography, optical coherence tomography, fluorescein angiography, and comparison of the results of FAF with the first visit, vitelliform macular dystrophy was suspected and a definite diagnosis was made by electrooculography and genetic testing. CONCLUSION: In patients with continuous serous retinal detachment without response to photodynamic therapy or intravitreal bevacizumab injection, careful fundus exam and FAF can be used to diagnose atypical vitelliform macular dystrophy

Time dependent CP asymmetry in B0→ρ0γB^0 \to \rho^0 \gamma decay to probe the origin of CP violation

Since the CP violation in the $B$ system has been investigated up to now only through processes related to the $B$--$\bar{B}$ mixing, urgently required is new way of study for the CP violation and establishing its origin in the $B$ system independent of the mixing process. In this work, we explore the exclusive $B^0 \to \rho^0 \gamma$ decay to obtain the time-dependent CP asymmetry in $b \to d$ decay process in the standard model and the supersymmetric model. We find that the complex RL and RR mass insertion to the squark sector in the MSSM can lead to a large CP asymmetry in $b \to d \gamma$ decay through the gluino-squark diagrams, which is not predicted in the Standard Model induced by the $B$--$\bar{B}$ mixing.Comment: 10 pages, 4 eps figure