154 research outputs found

    Stomach One-Point Cancer: One Case Report and Literature Review

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    Gastric cancer is one of the most common cancers and one of themost frequent causes of cancer deaths worldwide. Early detection andaccurate preoperative staging of gastric cancer is essential for planning optimal therapy such as endoscopic mucosal resection or gastric resection and offers the best prognosis. With advanced technology in diagnostic instruments and the mass screening, early gastric cancer has been detected easier. One-point cancer of gastric is a special type of early gastric cancer[1]. Diagnosis of one-point cancer of gastric is important for both the immediate treatment and the prognosis. There is still no consensus on the operation extent and postoperative treatment for patients with one-point cancer of gastric. Learned from previous reports[2-5], we know that existed in the superfi cial layer of the gastric mucosa and the superfi cial ulcer is one of the important characteristics of one point cancer of gastric. Herein, we report a case of one point cancer of gastric with the appearance of a deep infi ltrating ulcer. To the best of our knowledge, no such type of one point cancer of gastric has been reported

    Phenomenological Analysis of B->PP Decays with QCD Factorization

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    In this paper, we study nonleptonic charmless B decays to two light pseudoscalar mesons within the frame of QCD factorization, including the contributions from the chirally enhanced power corrections and weak annihilation. Predictions for the CP-averaged branching ratios and CP-violating asymmetries are given. Within the reasonable range of the parameters, we find that our predictions for the branching ratios of B -> PP are consistent with the present experimental data. But because of the logarithmic divergences at the endpoints in the hard spectator scatterings and weak annihilation, there are still large uncertainties in these predictions.Comment: 34 pages, 5 figures. to appear in PR

    Charmless BsPP,PV,VVB_s\to PP, PV, VV Decays Based on the six-quark Effective Hamiltonian with Strong Phase Effects II

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    We provide a systematic study of charmless BsPP,PV,VVB_s \to PP, PV, VV decays (PP and VV denote pseudoscalar and vector mesons, respectively) based on an approximate six-quark operator effective Hamiltonian from QCD. The calculation of the relevant hard-scattering kernels is carried out, the resulting transition form factors are consistent with the results of QCD sum rule calculations. By taking into account important classes of power corrections involving "chirally-enhanced" terms and the vertex corrections as well as weak annihilation contributions with non-trivial strong phase, we present predictions for the branching ratios and CP asymmetries of BsB_s decays into PP, PV and VV final states, and also for the corresponding polarization observables in VV final states. It is found that the weak annihilation contributions with non-trivial strong phase have remarkable effects on the observables in the color-suppressed and penguin-dominated decay modes. In addition, we discuss the SU(3) flavor symmetry and show that the symmetry relations are generally respected

    Determination of the η\eta and η\eta' Mixing Angle from the Pseudoscalar Transition Form Factors

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    The possible range of ηη\eta-\eta' mixing angle is determined from the transition form factors Fηγ(Q2)F_{\eta \gamma}(Q^2) and Fηγ(Q2)F_{\eta' \gamma}(Q^2) with the help of the present experimental data. For such purpose, the quark-flavor mixing scheme is adopted and the pseudoscalar transition form factors are calculated under the light-cone pQCD framework, where the transverse momentum corrections and the contributions beyond the leading Fock state have been carefully taken into consideration. We construct a phenomenological expression to estimate the contributions to the form factors beyond the leading Fock state based on their asymptotic behavior at Q20Q^2\to 0 and Q2Q^2\to\infty. By taking the quark-flavor mixing scheme, our results lead to ϕ=38.0±1.0±2.0\phi= 38.0^{\circ}\pm 1.0^{\circ}\pm 2.0^{\circ}, where the first error coming from experimental uncertainty and the second error coming from the uncertainties of the wavefunction parameters. The possible intrinsic charm component in η\eta and η\eta' is discussed and our present analysis also disfavors a large portion of intrinsic charm component in η\eta and η\eta', e.g. fηc50MeV|f^c_{\eta'}|\le 50 {\rm MeV}.Comment: 18 Pages, 3 figures. Several references added. To be published in EPJ

    Lepton flavor violation decays τμP1P2\tau^-\to \mu^- P_1 P_2 in the topcolor-assisted technicolor model and the littlest Higgs model with TT parity

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    The new particles predicted by the topcolor-assisted technicolor (TC2TC2) model and the littlest Higgs model with T-parity (called LHTLHT model) can induce the lepton flavor violation (LFVLFV) couplings at tree level or one loop level, which might generate large contributions to some LFVLFV processes. Taking into account the constraints of the experimental data on the relevant free parameters, we calculate the branching ratios of the LFVLFV decay processes τμP1P2\tau^-\to\mu^- P_1 P_2 with P1P2P_1 P_2 = π+π\pi^+\pi^-, K+KK^+K^- and K0K0ˉK^0\bar{K^0} in the context of these two kinds of new physics models. We find that the TC2TC2 model and the LHTLHT model can indeed produce significant contributions to some of these LFVLFV decay processes.Comment: 24 pages, 7 figure

    Nonfactorizable contributions in B decays to charmonium: the case of BKhcB^- \to K^- h_c

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    Nonleptonic BB to charmonium decays generally show deviations from the factorization predictions. For example, the mode BKχc0B^- \to K^- \chi_{c0} has been experimentally observed with sizeable branching fraction while its factorized amplitude vanishes. We investigate the role of rescattering effects mediated by intermediate charmed meson production in this class of decay modes, and consider BKhcB^- \to K^- h_c with hch_c the JPC=1+J^{PC}=1^{+-} cˉc\bar c c meson. Using an effective lagrangian describing interactions of pairs of heavy-light QqˉQ{\bar q} mesons with a quarkonium state, we relate this mode to the analogous mode with χc0\chi_{c0} in the final state. We find B(BKhc){\cal B}(B^- \to K^- h_c) large enough to be measured at the BB factories, so that this decay mode could be used to study the poorly known hch_c.Comment: RevTex, 16 pages, 2 eps figure

    Strong Phases and Factorization for Color Suppressed Decays

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    We prove a factorization theorem in QCD for the color suppressed decays B0-> D0 M0 and B0-> D*0 M0 where M is a light meson. Both the color-suppressed and W-exchange/annihilation amplitudes contribute at lowest order in LambdaQCD/Q where Q={mb, mc, Epi}, so no power suppression of annihilation contributions is found. A new mechanism is given for generating non-perturbative strong phases in the factorization framework. Model independent predictions that follow from our results include the equality of the B0 -> D0 M0 and B0 -> D*0 M0 rates, and equality of non-perturbative strong phases between isospin amplitudes, delta(DM) = delta(D*M). Relations between amplitudes and phases for M=pi,rho are also derived. These results do not follow from large Nc factorization with heavy quark symmetry.Comment: 38 pages, 6 figs, typos correcte

    An investigation into a suitable scintillator for localising neutron capture within a detector

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    Using Monte-Carlo modelling, an investigation into a suitable loaded scintillator for localising neutron capture in a novel neutron survey meter has been undertaken. A comparison of estimated neutron capture location in a scintillator with Geant4 and MCNP simulations was undertaken and a good general agreement between the two models was observed. The interactions of γ emissions from neutron capture in the scintillator are investigated. The results show that the γ emission from neutron capture will not aid neutron capture localisation and will only inhibit it. It is observed that the lithium-loaded scintillator has the lowest neutron capture efficiency when compared with boron and gadolinium scintillators. However, it is the most promising of the detectors investigated in this research for use in a novel neutron survey meter design
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