8,135 research outputs found

    Nonleptonic charmless two-body BATB \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 BATB\to AT decays (where AA and TT denotes a 3P1^3P_1 axial-vector and a tensor meson, respectively), using BTB \to T form factors obtained in the covariant light-front (CLF) approach, and the full effective Hamiltonian. We have obtained that B(B0a1+a2)=42.47×106\mathcal{B}(B^{0} \to a_{1}^{+}a_{2}^{-}) =42.47 \times10^{-6}, B(B+a1+a20)=22.71×106\mathcal{B}(B^{+} \to a_{1}^{+}a_{2}^{0}) = 22.71 \times10^{-6}, B(Bf1K2)=(2.84)×106\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(Bf1(1420)K2)=(5.916.42)×106\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(BK1a2)=(1.75.7)[19.3]×106\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(BK1(1270)a2)/B(BK1(1400)a2)\mathcal{B}(B \to K_{1}(1270)a_{2})/\mathcal{B}(B \to K_{1}(1400)a_{2}) and B(Bf1(1420)K2)/B(Bf1(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

    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 KJK_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 BKJ()B \to K_J^{(*)} transition form factors in the large recoil region in terms of two independent LEET functions ζKJ()\zeta_\perp^{K_J^{(*)}} and ζKJ()\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 BKJ()γB \to K_J^{(*)} \gamma, BKJ()+B \to K_J^{(*)} \ell^+ \ell^- and BKJ()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 BKJ()+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

    Direct CP Violation, Branching Ratios and Form Factors BπB \to \pi, BKB \to K in BB Decays

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    The BπB \to \pi and BKB \to K transitions involved in hadronic B decays are investigated in a phenomenological way through the framework of QCD factorization. By comparing our results with experimental branching ratios from the BELLE, BABAR and CLEO Collaborations for all the B decays including either a pion or a kaon, we propose boundaries for the transition form factors BπB \to \pi and BKB \to K depending on the CKM matrix element parameters ρ\rho and η\eta. From this analysis, the form factors required to reproduce the experimental data for branching ratios are FBπ=0.31±0.12F^{B \to \pi}= 0.31 \pm 0.12 and FBK=0.37±0.13F^{B \to K}= 0.37\pm 0.13. We calculate the direct CP violating asymmetry parameter, aCPa_{CP}, for Bπ+ππB \to \pi^{+} \pi^{-} \pi and Bπ+πKB \to \pi^{+} \pi^{-} K decays, in the case where ρω\rho-\omega mixing effects are taken into account. Based on these results, we find that the direct CP asymmetry for Bπ+ππB^{-} \to \pi^{+} \pi^{-} \pi^{-}, Bˉ0π+ππ0\bar{B}^{0} \to \pi^{+} \pi^{-} \pi^{0}, Bπ+πKB^{-} \to \pi^{+} \pi^{-} K^{-}, and Bˉ0π+πKˉ0\bar{B}^{0} \to \pi^{+} \pi^{-} \bar{K}^{0}, reaches its maximum when the invariant mass π+π\pi^{+} \pi^{-} is in the vicinity of the ω\omega meson mass. The inclusion of ρω\rho-\omega mixing provides an opportunity to erase, without ambiguity, the phase uncertainty mod(π)(\pi) in the determination of the CKM angles α\alpha in case of bub\to u and γ\gamma in case of bsb \to s.Comment: 74 pages, 15 figures, 8 tables. A few misprints corrected, two references adde

    SU(3) Predictions of BPPB\to PP Decays in the Standard Model

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    With SU(3) symmetry one only needs 13 hadronic parameters to describe BPPB\to PP decays in the Standard Model. When annihilation contributions are neglected, only 7 hadronic parameters are needed. These parameters can be determined from existing experimental data and some unmeasured branching ratios and CP asymmetries of the type BPPB\to PP can be predicted. In this talk we present SU(3) predictions of branching ratios and CP asymmetries for BPPB\to PP decays in the Standard Model.Comment: 4 pages, no figure. Talk present at the 5th International Conference on Hyperons, Charm and Beauty Hadrons, Vancouver, June 200

    Life table analysis of Diaphorina citri (Hemiptera: Psyllidae) infesting sweet orange (Citrus sinensis) in São Paulo

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    An ecological life table for eggs and nymphs of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) was constructed with data obtained from orange orchards (Citrus sinensis Osbeck) in 2 regions of the State of São Paulo, over 4 generations in the period from XI-2006 to V-2007, comprising spring, summer, and fall seasons. Young growing shoots with D. citri eggs present were identifed, and live individuals were counted until adult emergence. No predatory arthropods were observed in association with D. citri eggs and nymphs during the study. The mean parasitism of fourth- and ffth-instar nymphs by Tamarixia radiata Waterston (Hymenoptera: Eulophidae) was 2.3%. The durations of the egg–adult period were similar among the 4 generations, ranging from 18.0 to 24.7 d (at mean temperatures ranging from 21.6 to 26.0 °C) and followed the temperature requirement models obtained in the laboratory for D. citri. However, survival from the egg to the adult stage for the same period varied considerably from 1.7 to 21.4%; the highest mortalities were observed in the egg and small nymphal (frst- to thirdinstar) stages, which were considered to be key phases for population growth of the pest.Uma tabela de vida ecológica foi construída para ovos e ninfas de Diaphorina citri Kuwayama (Hemiptera: Psyllidae) com dados obtidos em pomares de laranja (Citrus sinensis Osbeck) em 2 regiões do estado de São Paulo, com 4 gerações, no período de novembro de 2006 a maio de 2007, compreendendo as estações de primavera, verão e outono. Ramos jovens em crescimento com a presença de ovos de D. citri foram identificados e os indivíduos vivos foram contados até a emergência dos adultos. Nenhum predador foi observado associado a ovos e ninfas de D. citri durante o estudo. A taxa média de parasitismo de ninfas de quarto e quinto ínstares por Tamarixia radiata Waterson (Hymenoptera: Eulophidae) foi de 2.3%. A duração do período de ovo a adulto foi semelhante entre as quatro gerações, variando de 18.0 a 24.7 dias (com temperaturas médias de 21.6 a 26.0 °C) e seguiram os modelos de exigencias térmicas obtidas em laboratório para D. citri. Todavia, a sobrevivencia de ovo até o estágio adulto variou consideravelmente para o mesmo período, de 1.7 a 21.4%, sendo que as maiores mortalidades foram observadas nos estágios de ovos e ninfas pequenas (de primeiro a terceiro ínstares), as quais foram consideradas fases chaves para o crescimento populacional desta praga.info:eu-repo/semantics/publishedVersio

    Using untagged B^0 -> D K_S to determine gamma

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    It is shown that the weak phase gamma=arg(-V_{ud}V^*_{ub}V_{cb}V_{cd}^*) can be determined using only untagged decays B/Bbar--> D K_S. In order to reduce the uncertainty in gamma, we suggest combining information from B^{+-}--> DK^{+-} and from untagged B^0 decays, where the D meson is observed in common decay modes. Theoretical assumptions, which may further reduce the statistical error, are also discussed.Comment: 18 pages, same as published versio

    Inelastic J/ΨJ/\Psi Photoproduction off Nuclei: Gluon Enhancement or Double Color Exchange?

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    The nuclear enhancement observed in inelastic photoproduction of J/ΨJ/\Psi should not be interpreted as evidence for an increased gluon density in nuclei. The nuclear suppression of the production rate due to initial and final state interactions is calculated and a novel two-step color exchange process is proposed, which is able to explain the data.Comment: Latex file, 23 pages including 5 Postscript figure

    Dark Matter in SuperGUT Unification Models

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    After a brief update on the prospects for dark matter in the constrained version of the MSSM (CMSSM) and its differences with models based on minimal supergravity (mSUGRA), I will consider the effects of unifying the supersymmetry-breaking parameters at a scale above M_{GUT}. One of the consequences of superGUT unification, is the ability to take vanishing scalar masses at the unification scale with a neutralino LSP dark matter candidate. This allows one to resurrect no-scale supergravity as a viable phenomenological model.Comment: 12 pages, 16 figures, To be published in the Proceedings of the 6th DSU Conference, Leon, Mexico, ed. D. Delepin
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