144 research outputs found

    Asymmetry Parameter of the K1(1270,1400)K_{1} (1270, 1400) by Analyzing the B→K1ννˉB\to K_{1}\nu \bar{\nu} Transition Form Factors within QCD

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    Separating the mixture of the K1(1270) K_{1}(1270) and K1(1400)K_{1}(1400) states, the B→K1(1270,1400)ννˉB\to K_{1}(1270, 1400)\nu\bar{\nu} transition form factors are calculated in the three-point QCD sum rules approach. The longitudinal, transverse and total decay widths as well as the asymmetry parameter, characterizing the polarization of the axial K1(1270,1400)K_{1}(1270, 1400) and the branching ratio for these decays are evaluated.Comment: 25 pages, 3 figures, 3 table

    Radiative and Semileptonic B Decays Involving Higher K-Resonances in the Final States

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    We study the radiative and semileptonic B decays involving a spin-JJ resonant KJ(∗)K_J^{(*)} with parity (−1)J(-1)^J for KJ∗K_J^* and (−1)J+1(-1)^{J+1} for KJK_J in the final state. Using the large energy effective theory (LEET) techniques, we formulate B→KJ(∗)B \to K_J^{(*)} transition form factors in the large recoil region in terms of two independent LEET functions ζ⊥KJ(∗)\zeta_\perp^{K_J^{(*)}} and ζ∥KJ(∗)\zeta_\parallel^{K_J^{(*)}}, the values of which at zero momentum transfer are estimated in the BSW model. According to the QCD counting rules, ζ⊥,∥KJ(∗)\zeta_{\perp,\parallel}^{K_J^{(*)}} exhibit a dipole dependence in q2q^2. We predict the decay rates for B→KJ(∗)γB \to K_J^{(*)} \gamma, B→KJ(∗)ℓ+ℓ−B \to K_J^{(*)} \ell^+ \ell^- and B→KJ(∗)ννˉB \to K_J^{(*)}\nu \bar{\nu}. The branching fractions for these decays with higher KK-resonances in the final state are suppressed due to the smaller phase spaces and the smaller values of ζ⊥,∥KJ(∗)\zeta^{K_J^{(*)}}_{\perp,\parallel}. Furthermore, if the spin of KJ(∗)K_J^{(*)} becomes larger, the branching fractions will be further suppressed due to the smaller Clebsch-Gordan coefficients defined by the polarization tensors of the KJ(∗)K_J^{(*)}. We also calculate the forward backward asymmetry of the B→KJ(∗)ℓ+ℓ−B \to K_J^{(*)} \ell^+ \ell^- decay, for which the zero is highly insensitive to the KK-resonances in the LEET parametrization.Comment: 27 pages, 4 figures, 7 tables;contents and figures corrected, title and references revise

    Forward-backward Asymmetry and Branching Ratio of B \rar K_1 \ell^+ \ell^- Transition in Supersymmetric Models

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    The mass eigen states K1(1270)K_1(1270) and K1(1400)K_1(1400) are mixture of the strange members of two axial-vector SU(3) octet, 3P1(K1A)^3P_1(K_1^A) and 1P1(K1B)^1P_1(K_1^B). Taking into account this mixture, the forward-backward asymmetry and branching ratio of B \rar K_1(1270,1400) \ell^+ \ell^- transitions are studied in the framework of different supersymmetric models. It is found that the results have considerable deviation from the standard model predictions. Any measurement of these physical observables and their comparison with the results obtained in this paper can give useful information about the nature of interactions beyond the standard model.Comment: 14 pages, 4 figure

    Nonleptonic charmless two-body B→ATB \to AT decays

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    In this work we have studied hadronic charmless two-body B decays involving p-wave mesons in final state. We have calculated branching ratios of B→ATB\to AT decays (where AA and TT denotes a 3P1^3P_1 axial-vector and a tensor meson, respectively), using B→TB \to T form factors obtained in the covariant light-front (CLF) approach, and the full effective Hamiltonian. We have obtained that B(B0→a1+a2−)=42.47×10−6\mathcal{B}(B^{0} \to a_{1}^{+}a_{2}^{-}) =42.47 \times10^{-6}, B(B+→a1+a20)=22.71×10−6\mathcal{B}(B^{+} \to a_{1}^{+}a_{2}^{0}) = 22.71 \times10^{-6}, B(B→f1K2∗)=(2.8−4)×10−6\mathcal{B}(B \to f_{1}K_{2}^{*}) = (2.8-4) \times 10^{-6} (with f1=,f1(1285),f1(1420)f_{1}=, f_{1}(1285),f_{1}(1420)) for θ3P1=53.2∘\theta_{^{3}P_{1}} = 53.2^{\circ}, B(B→f1(1420)K2∗)=(5.91−6.42)×10−6\mathcal{B}(B \to f_{1}(1420)K_{2}^{*}) = (5.91-6.42) \times 10^{-6} with θ3P1=27.9∘\theta_{^{3}P_{1}} = 27.9^{\circ}, B(B→K1a2)=(1.7−5.7)[1−9.3]×10−6\mathcal{B}(B \to K_{1}a_{2})= (1.7 - 5.7) [1-9.3] \times10^{-6} for θK1=−37∘[−58∘]\theta_{K_{1}} = -37^{\circ} [-58^{\circ}] where K1=K1(1270),K1(1400)K_1 = K_1(1270), K_1(1400). It seems that these decays can be measured in experiments at BB factories. Additionally, we have found that B(B→K1(1270)a2)/B(B→K1(1400)a2)\mathcal{B}(B \to K_{1}(1270)a_{2})/\mathcal{B}(B \to K_{1}(1400)a_{2}) and B(B→f1(1420)K2∗)/B(B→f1(1285)K2∗)\mathcal{B}(B \to f_1(1420)K_{2}^{*})/\mathcal{B}(B \to f_1(1285)K_{2}^{*}) ratios could be useful to determine numerical values of mixing angles θK1\theta_{K_{1}} and θ3P1\theta_{^{3}P_{1}}, respectively.Comment: 12 page

    Nonleptonic charmless two-body B decays involving tensor mesons in the covariant light-front approach

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    We reanalyzed nonleptonic charmless two-body B decays involving tensor mesons in final state motivated by the disagreement between current experimental information and theoretical predictions obtained in ISGW2 model for some B(B→P(V)T)\mathcal{B}(B \to P(V)T) (where PP, VV and TT denote a pseudoscalar, a vector and a tensor meson, respectively). We have calculated branching ratios of charmless B→PTB \to PT and B→VTB\to VT modes, using B→TB \to T form factors obtained in the covariant light-front (CLF) approach and the full effective Hamiltonian. We have considered the η−η′\eta-\eta^{\prime} two-mixing angle formalism for B→η(′)TB \to \eta^{(\prime)}T channels, which increases branching ratios for these processes. Our predictions obtained in the CLF approach are, in general, greater than those computed in the framework of the ISGW2 model and more favorable with the available experimental data. Specifically, our results for exclusive channels B→ηK2∗(1430)B \to \eta K_{2}^{*}(1430) and B→ϕK2∗(1430)B \to \phi K_{2}^{*}(1430) are in agreement with recent experimental information.Comment: 10 page

    Polarization transfer in the 16^{16}O(p,p′)(p,p') reaction at forward angles and structure of the spin-dipole resonances

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    Cross sections and polarization transfer observables in the 16^{16}O(p,p′)(p,p') reactions at 392 MeV were measured at several angles between θlab=\theta_{lab}= 0∘^\circ and 14∘^\circ. The non-spin-flip (ΔS=0{\Delta}S=0) and spin-flip (ΔS=1{\Delta}S=1) strengths in transitions to several discrete states and broad resonances in 16^{16}O were extracted using a model-independent method. The giant resonances in the energy region of Ex=19−E_x=19-27 MeV were found to be predominantly excited by ΔL=1{\Delta}L=1 transitions. The strength distribution of spin-dipole transitions with ΔS=1{\Delta}S=1 and ΔL=1{\Delta}L=1 were deduced. The obtained distribution was compared with a recent shell model calculation. Experimental results are reasonably explained by distorted-wave impulse approximation calculations with the shell model wave functions.Comment: 28 pages RevTex, including 9 figures, to be published in Phys. Rev. C.; a typo in Eq. (3b) was correcte

    Model Independent Analysis of the Forward-Backward Asymmetry for the B→K1μ+μ−B\to K_{1}\mu^{+}\mu^{-} Decay

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    The sensitivity of the zero position of the forward backward asymmetry AFB\mathcal{A}_{FB} for the exclusive B→K1(1270)μ+μ−B\rightarrow K_{1}(1270)\mu^{+}\mu^{-} decay is examined by using most general non-standard 4-fermion interactions. Our analysis shows that the zero position of the forward backward asymmetry is very sensitive to the sign and size of the Wilson coefficients corresponding to the new vector type interactions, which are the counter partners of the usual Standard Model operators but have opposite chirality. In addition to these, the other significant effect comes from the interference of Scalar-Pseudoscalar and Tensor type operators. These results will not only enhance our theoretical understanding about the axial vector mesons but will also serve as a good tool to look for physics beyond the SM.Comment: 14 pages, 8 figures, Published version that appears in EPJ

    A New Measurement of the Intruder Configuration in 12Be

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    A new 11^{11}Be(d,pd,p)12^{12}Be transfer reaction experiment was carried out in inverse kinematics at 26.9AA MeV, with special efforts devoted to the determination of the deuteron target thickness and of the required optical potentials from the present elastic scattering data. In addition, a direct measurement of the cross sections for the 02+_2^+ state was realized by applying an isomer-tagging technique. The s-wave spectroscopic factors of 0.20(0.04) and 0.41(0.11) were extracted for the 01+_1^+ and 02+_2^+ states, respectively, in 12^{12}Be. Using the ratio of these spectroscopic factors, together with the previously reported results for the p-wave components, the single-particle component intensities in the bound 0+^+ states of 12^{12}Be were deduced, allowing a direct comparison with the theoretical predictions. It is evidenced that the ground-state configuration of 12^{12}Be is dominated by the d-wave intruder, exhibiting a dramatic evolution of the intruding mechanism from 11^{11}Be to 12^{12}Be, with a persistence of the N=8N = 8 magic number broken

    The Acute Phase Protein Serum Amyloid A Induces Lipolysis and Inflammation in Human Adipocytes through Distinct Pathways

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    Background: The acute phase response (APR) is characterized by alterations in lipid and glucose metabolism leading to an increased delivery of energy substrates. In adipocytes, there is a coordinated decrease in Free Fatty acids (FFAs) and glucose storage, in addition to an increase in FFAs mobilization. Serum Amyloid A (SAA) is an acute phase protein mainly associated with High Density Lipoproteins (HDL). We hypothesized that enrichment of HDL with SAA, during the APR, could be implicated in the metabolic changes occurring in adipocytes. Methodology/Principal Findings: In vitro differentiated human adipocytes (hMADS) were treated with SAA enriched HDL or recombinant SAA and the metabolic phenotype of the cells analyzed. In hMADS, SAA induces an increased lipolysis through an ERK dependent pathway. At the molecular level, SAA represses PPARc2, C/EBPa and SREBP-1c gene expression, three transcription factors involved in adipocyte differentiation or lipid synthesis. In addition, the activation of the NF-kB pathway by SAA leads to the induction of pro-inflammatory cytokines and chemokines, as in the case of immune cells. These latter findings were replicated in freshly isolated mature human adipocytes. Conclusions/Significance: Besides its well-characterized role in cholesterol metabolism, SAA has direct metabolic effects on human adipocytes. These metabolic changes could be at least partly responsible for alterations of adipocyte metabolism observed during the APR as well as during pathophysiological conditions such as obesity and conditions leading to insuli
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