1,079 research outputs found

    Form Factors for Exclusive Semileptonic BB--Decays

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    We developed the new parton model approach for exclusive semileptonic decays of BB-meson to D, DD,~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 q2q^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 BργB \to \rho \gamma decay

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    We explore the exclusive B0ρ0γ B^0 \to \rho^0 \gamma decay to obtain the time-dependent CP asymmetry in bdγb \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

    Time dependent CP asymmetry in B0ρ0γB^0 \to \rho^0 \gamma decay to probe the origin of CP violation

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    Since the CP violation in the BB system has been investigated up to now only through processes related to the BB--Bˉ\bar{B} mixing, urgently required is new way of study for the CP violation and establishing its origin in the BB system independent of the mixing process. In this work, we explore the exclusive B0ρ0γ B^0 \to \rho^0 \gamma decay to obtain the time-dependent CP asymmetry in bdb \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 bdγb \to d \gamma decay through the gluino-squark diagrams, which is not predicted in the Standard Model induced by the BB--Bˉ\bar{B} mixing.Comment: 10 pages, 4 eps figure

    Soft Wilson lines in soft-collinear effective theory

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    The effects of the soft gluon emission in hard scattering processes at the phase boundary are resummed in the soft-collinear effective theory (SCET). In SCET, the soft gluon emission is decoupled from the energetic collinear part, and is obtained by the vacuum expectation value of the soft Wilson-line operator. The form of the soft Wilson lines is universal in deep inelastic scattering, in the Drell-Yan process, in the jet production from e+e- collisions, and in the gamma* gamma* -> pi0 process, but its analytic structure is slightly different in each process. The anomalous dimensions of the soft Wilson-line operators for these processes are computed along the light-like path at leading order in SCET and to first order in alpha_s, and the renormalization group behavior of the soft Wilson lines is discussed.Comment: 36 pages, 10 figures, 3 table

    New Physics Effects in BK()ννB \to K^(*) \nu \nu Decays

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    We present a model-independent analysis of rare B decays, BK()ννB \to K^{(*)} \nu \nu. The effect of possible new physics is written in terms of dimension-6 four-fermi interactions. The lepton number violating scalar- and tensor-type interactions are included, and they induce BK()νν(νˉνˉ)B \to K^{(*)} \nu \nu ({\bar \nu} {\bar \nu}) decays. We show systematically how the branching ratios and missing mass-squared spectrum depend on the coefficients of the four-fermi interactions.Comment: 20 pages with 7 figure

    bsγb \to s \gamma decays in the Left-Right Symmetric Model

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    We consider bsγb \to s \gamma decays in the Left-Right Symmetric Model. Values of observables sensitive to chiral structure such as the Λ\Lambda polarization in the ΛbΛγ\Lambda_b \to \Lambda \gamma decays and the mixing-induced CP asymmetries in the Bd,sM0γB_{d,s} \to M^0 \gamma decays can deviate in the LRSM significantly from the SM values. The combined analysis of PΛP_\Lambda and ACPA_{CP} as well as BR(bsγ){\cal BR}(b \to s \gamma) can be used to determine the model parameters.Comment: 16 pages with 7 figures, Version to be published in PR

    Singlet Fermionic Dark Matter explains DAMA signal

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    It has been suggested that, considering channeling effect, the order of a few GeV dark matters which are elastically scattered from detector nuclei might be plausible candidates reconciling the DAMA annual modulation signal with the results of other null experiments. We show that Singlet Fermionic Dark Matter can be such a dark matter candidate, simultaneously providing the correct thermal relic density which is consistent with the WMAP data.Comment: 9 pages, 3 figure

    Exome-based Variant Detection in Core Promoters.

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    Core promoter controls the initiation of transcription. Core promoter sequence change can disrupt transcriptional regulation, lead to impairment of gene expression and ultimately diseases. Therefore, comprehensive characterization of core promoters is essential to understand normal and abnormal gene expression in biomedical studies. Here we report the development of EVDC (Exome-based Variant Detection in Core promoters) method for genome-scale analysis of core-promoter sequence variation. This method is based on the fact that exome sequences contain the sequences not only from coding exons but also from non-coding region including core promoters generated by random fragmentation in exome sequencing process. Using exome data from three cell types of CD4+ T cells, CD19+ B cells and neutrophils of a single individual, we characterized the features of core promoter-mapped exome sequences, and analysed core-promoter variation in this individual genome. We also compared the core promoters between YRI (Yoruba in Ibadan, Nigeria) and the CEU (Utah residents of European decedent) populations using the exome data generated by the 1000 Genome project, and observed much higher variation in YRI population than in CEU population. Our study demonstrates that the EVDC method provides a simple but powerful means for genome-wile de novo characterization of core promoter sequence variation
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