66 research outputs found

    Asymmetry Parameter of the K1(1270,1400)K_{1} (1270, 1400) by Analyzing the BK1ννˉB\to K_{1}\nu \bar{\nu} Transition Form Factors within QCD

    Full text link
    Separating the mixture of the K1(1270) K_{1}(1270) and K1(1400)K_{1}(1400) states, the BK1(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

    BK1(1270)(ρK)+B \to K_1(1270) (\to \rho K) \ell^+ \ell^- in LEET

    Full text link
    Flavour Changing Neutral Current decays of the BB-meson are a very useful tool for studying possible physics scenarios beyond the Standard Model (SM), where of the many FCNC modes radiative, purely leptonic and semi-leptonic decays of the BB-meson are relatively clean tests. Within this context the BELLE collaboration has searched for the BK1(1270)γB \to K_1(1270) \gamma process and provided an upper bound on this decay. In this work we have used this upper bound in studying the angular coorelations for the related semi-leptonic decay mode BK1(1270)(ρK)+B \to K_1(1270) (\to \rho K) \ell^+ \ell^-, where we have used the form factors that have already been estimated for the BK1(1270)γB \to K_1(1270) \gamma mode. Note that the additional form factors that are required were calculated using the Large Energy Effective Theory (LEET).Comment: 13 pages, 4 figure

    Annihilation Contributions in B -> K_1 gamma decay in next-to-leading order in LEET and CP-asymmetry

    Full text link
    The effect of weak annihilation and u-quark penguin contribution on the branching ratio B -> K_1 gamma at next-to-leading order of alpha_s are calculated using LEET approach. It is shown that the value of LEET form factor remains the same in the range of unitarity triangle phase alpha favored by the Standard Model. CP-asymmetry for above mentioned decay has been calculated and its suppression due to the hard spectator correction has also been incorporated. In addition, the sensitivity of the CP-asymmetry on the underlying parameters has been discussed.Comment: 12 pages, 10 figure

    Model Independent Analysis of the Forward-Backward Asymmetry for the BK1μ+μB\to K_{1}\mu^{+}\mu^{-} Decay

    Full text link
    The sensitivity of the zero position of the forward backward asymmetry AFB\mathcal{A}_{FB} for the exclusive BK1(1270)μ+μB\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

    Rare Decays of \Lambda_b->\Lambda + \gamma and \Lambda_b ->\Lambda + l^{+} l^{-} in the Light-cone Sum Rules

    Full text link
    Within the Standard Model, we investigate the weak decays of ΛbΛ+γ\Lambda_b \to \Lambda + \gamma and ΛbΛ+l+l\Lambda_b \to \Lambda + l^{+} l^{-} with the light-cone sum rules approach. The higher twist distribution amplitudes of Λ\Lambda baryon to the leading conformal spin are included in the sum rules for transition form factors. Our results indicate that the higher twist distribution amplitudes almost have no influences on the transition form factors retaining the heavy quark spin symmetry, while such corrections can result in significant impacts on the form factors breaking the heavy quark spin symmetry. Two phenomenological models (COZ and FZOZ) for the wave function of Λ\Lambda baryon are also employed in the sum rules for a comparison, which can give rise to the form factors approximately 5 times larger than that in terms of conformal expansion. Utilizing the form factors calculated in LCSR, we then perform a careful study on the decay rate, polarization asymmetry and forward-backward asymmetry, with respect to the decays of ΛbΛγ\Lambda_b \to \Lambda \gamma, Λl+l\Lambda l^{+}l^{-}.Comment: 38 pages, 15 figures, some typos are corrected and more references are adde

    Form factors and branching ratio for the B -> l nu gamma decay

    Full text link
    Form factors parameterizing radiative leptonic decays of heavy mesons (B+γl+νl)% (B^{+}\to \gamma l^{+}\nu_{l}) for photon energy are computed in the language of dispersion relation. The contributing states to the absorptive part in the dispersion relation are the multiparticle continum, estimated by quark triangle graph and resonances with quantum numbers 11^{-} and 1+1^{+} which includes BB^{*} and BAB_{A}^{*} and thier radial excitations, which model the higher state contributions. Constraints provided by the asymptotic behavior of the structure dependent amplitude, Ward Identities and gauge invariance are used to provide useful information for parameters needed. The couplings gBBγg_{BB^{*}\gamma} and % f_{BB_{A}^{*}\gamma} are predicted if we restrict to first radial excitation; otherwise using these as an input the radiative decay coupling constants for radial excitations are predicted. The value of the branching ratio for the process B+γμ+νμB^{+}\to \gamma \mu ^{+}\nu_{\mu} is found to be in the range 0.5×1060.5\times 10^{-6}. A detailed comparison is given with other approaches.Comment: 22 pages+two ps figures; Paper has been throughly revised and Sudakov resummation has been discussed; published versio

    Considerations for the Use of Phage Therapy in Clinical Practice

    Get PDF
    Increasing antimicrobial resistance and medical device-related infections have led to a renewed interest in phage therapy as an alternative or adjunct to conventional antimicrobials. Expanded access and compassionate use cases have risen exponentially but have varied widely in approach, methodology, and clinical situations in which phage therapy might be considered. Large gaps in knowledge contribute to heterogeneity in approach and lack of consensus in many important clinical areas. The Antibacterial Resistance Leadership Group (ARLG) has convened a panel of experts in phage therapy, clinical microbiology, infectious diseases, and pharmacology, who worked with regulatory experts and a funding agency to identify questions based on a clinical framework and divided them into three themes: potential clinical situations in which phage therapy might be considered, laboratory testing, and pharmacokinetic considerations. Suggestions are provided as answers to a series of questions intended to inform clinicians considering experimental phage therapy for patients in their clinical practices

    Scientific rationale for Uranus and Neptune <i>in situ</i> explorations

    Get PDF
    The ice giants Uranus and Neptune are the least understood class of planets in our solar system but the most frequently observed type of exoplanets. Presumed to have a small rocky core, a deep interior comprising ∼70% heavy elements surrounded by a more dilute outer envelope of H2 and He, Uranus and Neptune are fundamentally different from the better-explored gas giants Jupiter and Saturn. Because of the lack of dedicated exploration missions, our knowledge of the composition and atmospheric processes of these distant worlds is primarily derived from remote sensing from Earth-based observatories and space telescopes. As a result, Uranus's and Neptune's physical and atmospheric properties remain poorly constrained and their roles in the evolution of the Solar System not well understood. Exploration of an ice giant system is therefore a high-priority science objective as these systems (including the magnetosphere, satellites, rings, atmosphere, and interior) challenge our understanding of planetary formation and evolution. Here we describe the main scientific goals to be addressed by a future in situ exploration of an ice giant. An atmospheric entry probe targeting the 10-bar level, about 5 scale heights beneath the tropopause, would yield insight into two broad themes: i) the formation history of the ice giants and, in a broader extent, that of the Solar System, and ii) the processes at play in planetary atmospheres. The probe would descend under parachute to measure composition, structure, and dynamics, with data returned to Earth using a Carrier Relay Spacecraft as a relay station. In addition, possible mission concepts and partnerships are presented, and a strawman ice-giant probe payload is described. An ice-giant atmospheric probe could represent a significant ESA contribution to a future NASA ice-giant flagship mission

    High Resolution Sharp Computational Methods for Elliptic and Parabolic Problems in Complex Geometries

    Full text link
    corecore