9,206 research outputs found

    Implications for new physics from Bˉ0π0π0{\bar B}^0\to \pi^0\pi^0 and Bˉ0Kˉ0K0{\bar B}^0\to {\bar K}^0K^0

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    We have analyzed the Bˉ0π0π0{\bar B}^0\to \pi^0\pi^0 puzzle in three kinds of models beyond the standard model (SM). It is shown that the minimal flavor violation (MFV) models, the minimal supersymmetric standard model (MSSM), and the two Higgs doublet models (2HDM) I and II can not give an explanation of the Bˉ0π0π0{\bar B}^0\to \pi^0\pi^0 puzzle within 1σ1 \sigma experimental bounds and the model III 2HDM can explain the puzzle without a conflict with other experimental measurements. If the constraint on C8gC_{8g} from bsgb\to s g is not imposed, for all kinds of insertions considered there are regions of parameter space, where the scalar quark mass is larger (much larger) than the gluino mass in the case of LR or RL (LL or RR), in which the puzzle can be resolved within 1σ1 \sigma experimental bounds.Comment: 7 pages, 3 eps files. Add some more explicit analysis version appeared in PL

    Dietary Blueberry and Bifidobacteria Attenuate Nonalcoholic Fatty Liver Disease in Rats by Affecting SIRT1-Mediated Signaling Pathway

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    NAFLD model rats were established and divided into NAFLD model (MG group), SIRT1 RNAi (SI group), blueberry juice (BJ group), blueberry juice + bifidobacteria (BJB group), blueberry juice + SIRT1 RNAi (BJSI group), and blueberry juice + bifidobacteria + SIRT1 RNAi groups (BJBSI group). A group with normal rats was a control group (CG). BJB group ameliorated NAFLD, which was better than BJ group (P<0.05). The lipid accumulation was lower in CG, BJ, and BJB groups than that in MG, SI, BJSI, and BJBSI groups (P<0.05). The levels of SIRT1 and PPAR-α were higher in CG, BJ, and BJB groups than those in MG, SI, BJSI, and BJBSI groups (P<0.05). The levels of SREBP-1c were lower in CG, BJ, and BJB groups than those in MG, SI, BJSI, and BJBSI groups (P<0.05). The biochemical indexes SOD, GSH, and HDL-c were improved from CG to BJB group (P<0.05). Inversely, the levels of AST and ALT, TG, TC, LDL-c, and MDA were decreased from CG to BJB group (P<0.05). These changes enhance antioxidative capability and biochemical index of rats. Blueberry juice and bifidobacteria improve NAFLD by activating SIRTI-mediating signaling pathway

    Clinical and radiological presentations of pelvic parachordoma

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    Parachordoma is an extremely rare entity and there are only about 50 to 60 cases reported, in which there is only one definite pelvic parachordoma. We present a huge well-defined presacral tumor in a 48-year-old woman who has the symptoms of lower abdominal pain and difficulty in defecating. Radiological findings of the tumor on computed tomography and magnetic resonance imaging are described in detail. The reasons why we report the case are because the patient has rare clinical symptoms and because this is the second pelvic parachordoma. Then, we summarize the radiological features of parachordoma based on our study and the review of literature

    Transmission resonance in a composite plasmonic structure

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    The design, fabrication, and optical properties of a composite plasmonic structure, a two-dimentional array of split-ring resonators inserted into periodic square holes of a metal film, have been reported. A new type of transmission resonance, which makes a significant difference from the conventional peaks, has been suggested both theoretically and experimentally. To understand this effect, a mechanism of ring- resonance induced dipole emission is proposed.Comment: 14 pages, 4 figure

    Singlet-triplet transitions in highly correlated nanowire quantum dots

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    We consider a quantum dot embedded in a three-dimensional nanowire with tunable aspect ratio a. A configuration interaction theory is developed to calculate the energy spectra of the finite 1D quantum dot systems charged with two electrons in the presence of magnetic fields B along the wire axis. Fruitful singlet-triplet transition behaviors are revealed and explained in terms of the competing exchange interaction, correlation interaction, and spin Zeeman energy. In the high aspect ratio regime, the singlet-triplet transitions are shown designable by tuning the parameters a and B. The transitions also manifest the highly correlated nature of long nanowire quantum dots.Comment: 4 pages, 4 figure

    Neutral Higgs boson contributions to CP asymmetry of BΦKSB \to \Phi K_S in MSSM

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    We have studied the neutral Higgs boson (NHB) contributions to the pure penguin process BϕKSB\to \phi K_S in MSSM with middle and large tanβ\tan\beta (say, >> 8). We show that the αs\alpha_s order hadronic matrix elements of NHB induced operators can make sizable effects on both the branch ratio and time dependent CP asymmetry SϕKS_{\phi K}. Under the all relevant experimental constraints, the Higgs mediated contributions to SϕKS_{\phi K} alone can provide a significant deviation from SM and, in particular, lead to a negative SϕKS_{\phi K} which is reported by BaBar and Belle.Comment: 7 pages and 6 figure

    CP asymmetries in BϕKSB\to \phi K_S and BηKSB\to \eta' K_S in MSSM

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    We study the BϕKSB\to \phi K_S and B\to \ep K_S decays in MSSM by calculating hadronic matrix elements of operators with QCD factorization approach and including neutral Higgs boson (NHB) contributions. We calculate the Wilson coefficients of operators including the new operators which are induced by NHB penguins at LO using the MIA with double insertions. We calculate the αs\alpha_s order hadronic matrix elements of the new operators for BϕKsB\to \phi K_s and BηKsB\to \eta^\prime K_s. It is shown that the recent experimental results on the time-dependent CP asymmetries in BϕKSB\to \phi K_S and B\to \ep K_S, SϕKS_{\phi K} is negative and SηKS_{\eta^{\prime} K} is positive, which can not be explained in SM, can be explained in MSSM if there are flavor non-diagonal squark mass matrix elements of 2nd and 3rd generations whose size satisfies all relevant constraints from known experiments (BXSγ,Bsμ+μ,BXsμ+μ,BXsg,ΔMsB\to X_S\gamma, B_s\to \mu^+\mu^-, B\to X_s \mu^+\mu^-, B\to X_s g, \Delta M_s, etc.). In particular, we find that one can explain the experimental results with a flavor non-diagonal mass insertion of any chirality when αs\alpha_s corrections of hadronic matrix elements of operators are included, in contrast with the claim in the literature. At the same time, the branching ratios for the two decays can also be in agreement with experimental measurements.Comment: 21 pages, 23 figures. Some changes have been made, which include comments on contributions to BϕKSB\to \phi K_S and BηKSB\to \eta' K_S from RR and RL insertion and some typing error
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