182 research outputs found

    Radiative transition of negative to positive parity nucleon

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    We investigate the N∗(1535)→NγN^{\ast}(1535)\rightarrow N\gamma transition in the framework of light cone QCD sum rules. In particular, using the most general form of the interpolating current for the nucleon as well as the distribution amplitudes of the photon, we calculate two transition form factors responsible for this channel and use them to evaluate the decay width and branching ratio of the transition under consideration. The result obtained for the branching fraction is in a good consistency with the experimental data.Comment: A typo has been correcte

    Investigation of the semileptonic transition of the BB into the orbitally excited charmed tensor meson

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    The transition form factors of the semileptonic B→D2∗(2460)ℓνˉ    (ℓ=τ,μ,e)B \rightarrow D_2^*(2460)\ell\bar{\nu}\,\,\,\,(\ell=\tau,\mu,e) decay channel are calculated within the framework of the three-point QCD sum rules. The fit functions of the form factors are then used to estimate the total decay width and branching ratio of this transition. The order of branching ratio shows that this channel can be detected at LHCb.Comment: 15 Pages, 4 Figures and 5 Table

    Anomalous magnetic moment of the muon in the two Higgs doublet model

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    We calculate the new physics effects on the anomalous magnetic moment of the muon in the framework of the two Higgs doublet model. We predict an upper bound for the lepton flavor violating coupling, which is responsible for the point like interaction between muon and tau, by using the uncertainty in the experimental result of the muon anomalous magnetic moment. We show that the upper bound predicted is more stringent compared to the one which is obtained by using the experimental result of the muon electric dipole momentComment: 8 Pages, 5 Figure

    The strong ΛbNB\Lambda_bNB and ΛcND\Lambda_cND vertices

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    We investigate the strong vertices among Λb\Lambda_b, nucleon and BB meson as well as Λc\Lambda_c, nucleon and DD meson in QCD. In particular, we calculate the strong coupling constants gΛbNBg_{\Lambda_bNB} and gΛcNDg_{\Lambda_cND} for different Dirac structures entered the calculations. In the case of ΛcND\Lambda_cND vertex, the result is compared with the only existing prediction obtained at Q2=0Q^2=0.Comment: 12 Pages, 3 Figures and 4 Table

    Scalar and vector self-energies of heavy baryons in nuclear medium

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    The in-medium sum rules are employed to calculate the shifts in the mass and residue as well as the scalar and vector self-energies of the heavy ΛQ,ΣQ\Lambda_Q, \Sigma_Q and ΞQ\Xi_Q baryons, with Q being bb or cc quark. The maximum shift in mass due to nuclear matter belongs to the Σc\Sigma_c baryon and it is found to be ΔmΣc=−936 MeV\Delta m_{\Sigma_{c}}=-936 ~ MeV. In the case of residue, it is obtained that the residue of Σb\Sigma_b baryon is maximally affected by the nuclear medium with the shift ΔλΣb=−0.014 GeV3\Delta \lambda_{\Sigma_b} = -0.014 ~ GeV^3 . The scalar and vector self-energies are found to be ΣΛbS=653 MeV\Sigma^{S}_{\Lambda_b} = 653 ~ MeV, ΣΣbS=−614 MeV\Sigma^{S}_{\Sigma_b} = -614 ~ MeV , ΣΞbS=−17 MeV\Sigma^{S}_{\Xi_b} = -17 ~ MeV , ΣΛcS=272 MeV\Sigma^{S}_{\Lambda_c} = 272 ~ MeV , ΣΣcS=−936 MeV\Sigma^{S}_{\Sigma_c} = -936 ~ MeV , ΣΞcS=−5 MeV\Sigma^{S}_{\Xi_c} = -5 ~ MeV and ΣΛbν=436±148 MeV\Sigma^{\nu}_{\Lambda_b} = 436 \pm 148 ~ MeV , ΣΣbν=382±129 MeV\Sigma^{\nu}_{\Sigma_b} = 382 \pm 129 ~MeV , ΣΞbν=15±5 MeV\Sigma^{\nu}_{\Xi_b} =15 \pm 5 ~ MeV, ΣΛcν=151±45 MeV\Sigma^{\nu}_{\Lambda_c} = 151 \pm 45 ~ MeV , ΣΣcν=486±144 MeV\Sigma^{\nu}_{\Sigma_c} = 486 \pm 144 ~ MeV and ΣΞcν=1.391±0.529 MeV\Sigma^{\nu}_{\Xi_c} = 1.391 \pm 0.529 ~ MeV .Comment: 13 Pages, 11 Figures and 5 Table

    On the strong coupling N(∗)N(∗)πN^{(*)}N^{(*)}\pi

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    We study the strong vertices N∗NπN^*N\pi, N∗N∗πN^*N^*\pi and NNπNN\pi in QCD, where N∗N^* denotes the negative parity N(1535)N (1535) state. We use the most general form of the interpolating currents to calculate the corresponding strong coupling constants. It is obtained that the coupling associated to N∗NπN^*N\pi vertex is strongly suppressed compared to those related to two other vertices. The strong coupling corresponding to N∗N∗πN^*N^*\pi is obtained to be roughly half of that of NNπNN\pi vertex. We compare the obtained results on N∗NπN^*N\pi and NNπNN\pi vertices with the existing predictions of other theoretical studies as well as those extracted from the experimental data.Comment: 15 Pages, 4 Figures and 3 Table

    Strong couplings of negative and positive parity nucleons to the heavy baryons and mesons

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    The strong coupling form factors related to the strong vertices of the positive and negative parity nucleons with the heavy Λb[c][Σb[c]]\Lambda_{b[c]}[\Sigma_{b[c]}] baryons and heavy B∗[D∗]B^*[D^*] vector mesons are calculated using a three-point correlation function. Using the values of the form factors at Q2=−mmeson2Q^2=-m^2_{meson} we compute the strong coupling constants among the participating particles.Comment: 12 Pages and 7 Table
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