1,687 research outputs found

    Radiative B decays to the axial KK mesons at next-to-leading order

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    We calculate the branching ratios of BK1γB\to K_1\gamma at next-to-leading order (NLO) of αs\alpha_s where K1K_1 is the orbitally excited axial vector meson. The NLO decay amplitude is divided into the vertex correction and the hard spectator interaction part. The one is proportional to the weak form factor of BK1B\to K_1 transition while the other is a convolution between light-cone distribution amplitudes and hard scattering kernel. Using the light-cone sum rule results for the form factor, we have \calB(B^0\to K_1^0(1270)\gamma)=(0.828\pm0.335)\times 10^{-5} and \calB(B^0\to K_1^0(1400)\gamma)=(0.393\pm0.151)\times 10^{-5}.Comment: 17pages, 4 figures. Minor changes, typos corrected. PRD accepted versio

    NEEMO 20: Science Training, Operations, and Tool Development

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    The 20th mission of the National Aeronautics and Space Administration (NASA) Extreme Environment Mission Operations (NEEMO) was a highly integrated evaluation of operational protocols and tools designed to enable future exploration beyond low-Earth orbit. NEEMO 20 was conducted from the Aquarius habitat off the coast of Key Largo, FL in July 2015. The habitat and its surroundings provide a convincing analog for space exploration. A crew of six (comprised of astronauts, engineers, and habitat technicians) lived and worked in and around the unique underwater laboratory over a mission duration of 14-days. Incorporated into NEEMO 20 was a diverse Science Team (ST) comprised of geoscientists from the Astromaterials Research and Exploration Science (ARES/XI) Division from the Johnson Space Center (JSC), as well as marine scientists from the Department of Biological Sciences at Florida International University (FIU). This team trained the crew on the science to be conducted, defined sampling techniques and operational procedures, and planned and coordinated the science focused Extra Vehicular Activities (EVAs). The primary science objectives of NEEMO 20 was to study planetary sampling techniques and tools in partial gravity environments under realistic mission communication time delays and operational pressures. To facilitate these objectives two types of science sites were employed 1) geoscience sites with available rocks and regolith for testing sampling procedures and tools and, 2) marine science sites dedicated to specific research focused on assessing the photosynthetic capability of corals and their genetic connectivity between deep and shallow reefs. These marine sites and associated research objectives included deployment of handheld instrumentation, context descriptions, imaging, and sampling; thus acted as a suitable proxy for planetary surface exploration activities. This abstract briefly summarizes the scientific training, scientific operations, and tool development conducted during NEEMO 20 with an emphasis on the primary lessons learned

    Newly observed two-body decays of B mesons in a hybrid perspective

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    In consistency with the b --> c type of (quasi) two body decays, recently observed two body decays of B mesons are studied in a hybrid perspective in which their amplitude is given by a sum of factorizable and non-factorizable ones, and a role of the latter in these decays are discussed.Comment: 7 page

    Photon polarization in radiative B decays

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    We study decay distributions in B -> K pi pi gamma, combining contributions from several overlapping resonances in a K pi pi mass range near 1400 MeV, (1^+) K_1(1400), (2^+) K^*_2(1430) and (1^-) K^*(1410). A method is proposed for using these distributions to determine a photon polarization parameter in the effective radiative weak Hamiltonian. This parameter is measured through an up-down asymmetry of the photon direction relative to the K pi pi decay plane. We calculate a dominant up-down asymmetry of 0.33 +- 0.05 from the K1(1400) resonance, which can be measured with about 10^8 B B-bar pairs, thus providing a new test for the Standard Model and a probe for some of its extensions.Comment: 22 pages, 3 figures, version to appear in Phys. Rev.

    Test of the Running of αs\alpha_s in τ\tau Decays

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    The τ\tau decay rate into hadrons of invariant mass smaller than s0ΛQCD\sqrt{s_0}\gg\Lambda_{\rm QCD} can be calculated in QCD assuming global quark--hadron duality. It is shown that this assumption holds for s0>0.7s_0>0.7~GeV2^2. From measurements of the hadronic mass distribution, the running coupling constant αs(s0)\alpha_s(s_0) is extracted in the range 0.7~GeV2<s0<mτ2^2<s_0<m_\tau^2. At s0=mτ2s_0=m_\tau^2, the result is αs(mτ2)=0.329±0.030\alpha_s(m_\tau^2)=0.329\pm 0.030. The running of αs\alpha_s is in good agreement with the QCD prediction.Comment: 9 pages, 3 figures appended; shortened version with new figures, to appear in Physical Review Letters (April 1996

    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

    Implications of Recent Bˉ0D()0X0\bar{B}^0\to D^{(*)0}X^0 Measurements

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    The recent measurements of the color-suppressed modes Bˉ0D()0π0\bar B^0\to D^{(*)0}\pi^0 imply non-vanishing relative final-state interaction (FSI) phases among various BˉDπ\bar B\to D\pi decay amplitudes. Depending on whether or not FSIs are implemented in the topological quark-diagram amplitudes, two solutions for the parameters a1a_1 and a2a_2 are extracted from data using various form-factor models. It is found that a2a_2 is not universal: a2(Dπ)=0.400.55|a_2(D\pi)|= 0.40-0.55 and a2(Dπ)=0.250.35|a_2(D^*\pi)|= 0.25-0.35 with a relative phase of order (5055)(50-55)^\circ between a1a_1 and a2a_2. If FSIs are not included in quark-diagram amplitudes from the outset, a2eff/a1effa_2^{eff}/a_1^{eff} and a2effa_2^{eff} will become smaller. The large value of a2(Dπ)|a_2(D\pi)| compared to a2eff(Dπ)|a_2^{eff}(D\pi)| or naive expectation implies the importance of long-distance FSI contributions to color-suppressed internal WW-emission via final-state rescatterings of the color-allowed tree amplitude.Comment: 17 pages. The Introduction is substantially revised and the order of the presentation in Sec. 2 is rearranged. To appear in Phys. Re

    1/m_Q Corrections to the Heavy-to-Light-Vector Transitions in the HQET

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    Within the HQET, the heavy to light vector meson transitions are systematically analyzed to the order of 1/m_Q. Besides the four universal functions at the leading order, there are twenty-two independent universal form factors at the order of 1/m_Q. Both the semileptonic decay B->\rho which is relevant to the |V_{ub}| extraction, and the penguin induced decay B -> K^* which is important to new physics discovering, depend on these form factors. Phenomenological implications are discussed.Comment: RevTeX, 9 pages, no figure

    P and CP violation in B physics

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    While the Kobayashi--Maskawa single phase origin of CP violation passed its first crucial precision test in BJ/ψKSB\to J/\psi K_S, the chirality of weak bb-quark couplings has not yet been carefully tested. We discuss recent proposals for studying the chiral and CP-violating structure of these couplings in radiative and in hadronic B decays.Comment: 15 pages, talk at PASCOS'03, Tata Inst., Mumbai, Jan. 200
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