17,010 research outputs found

    The B -> pi pi, pi K Puzzles: Implications for Hadron Physics, New Physics and Rare Decays

    Full text link
    The B-meson system is an interesting probe for the exploration of strong interactions, the quark-flavour sector of the Standard Model, and the search for new physics. In this programme, non-leptonic B decays, which are particularly challenging from the point of view of QCD, play a key role. After discussing strategies to deal with the corresponding hadronic matrix elements of four-quark operators and popular avenues for new physics to manifest itself in B decays, we focus on puzzling patterns in the B-factory data for B -> pi pi, pi K decays; we explore their implications for hadron physics, new physics and rare K and B decays.Comment: 10 pages, 2 figures, plenary talk at the International Conference on QCD and Hadronic Physics, Peking University, Beijing, China, 16-20 June 2005, to appear in the Proceeding

    Microphysical, microchemical and adhesive properties of lunar material. 3: Gas interaction with lunar material

    Get PDF
    Knowledge of the reactivity of lunar material surfaces is important for understanding the effects of the lunar or space environment upon this material, particularly its nature, behavior and exposure history in comparison to terrestrial materials. Adsorptive properties are one of the important techniques for such studies. Gas adsorption measurements were made on an Apollo 12 ultrahigh vacuum-stored sample and Apollo 14 and 15 N2-stored samples. Surface area measurements were made on the latter two. Adsorbate gases used were N2, A, O2 and H2O. Krypton was used for the surface area determinations. Runs were made at room and liquid nitrogen temperature in volumetric and gravimetric systems. It was found that the adsorptive/desorptive behavior was in general significantly different from that of terrestrial materials of similar type and form. Specifically (1) the UHV-stored sample exhibited very high initial adsorption indicative of high surface reactivity, and (2) the N2-stored samples at room and liquid nitrogen temperatures showed that more gas was desorbed than introduced during adsorption, indicative of gas release from the samples. The high reactivity is a scribed cosmic ray track and solar wind damage

    The photon polarization in B -> X gamma in the standard model

    Full text link
    The standard model prediction for the BXs,dγB\to X_{s,d}\gamma decay amplitude with a right-handed photon is believed to be tiny, suppressed by ms,d/mbm_{s,d}/m_b, compared to the amplitude with a left-handed photon. We show that this suppression is fictitious: in inclusive decays, the ratio of these two amplitudes is only suppressed by gs/(4π)g_s/(4\pi), and in exclusive decays by ΛQCD/mb\Lambda_{QCD}/m_b. The suppression is not stronger in BXdγB\to X_d\gamma decays than it is in BXsγB\to X_s\gamma. We estimate that the time dependent CP asymmetries in BKγB\to K^*\gamma, ργ\rho\gamma, KSπ0γK_S\pi^0\gamma, and π+πγ\pi^+\pi^-\gamma are of order 0.1 and that they have significant uncertainties.Comment: Clarifications in the exclusive section, references adde

    Microchemical, microphysical and adhesive properties of Apollo 11 and 12 Final report, 1 Aug. 1969 - 15 Mar. 1971

    Get PDF
    Gas exposure experiments of lunar soil with microchemical, microphysical, and adhesion analysi

    Dynamics of Black Hole Pairs II: Spherical Orbits and the Homoclinic Limit of Zoom-Whirliness

    Full text link
    Spinning black hole pairs exhibit a range of complicated dynamical behaviors. An interest in eccentric and zoom-whirl orbits has ironically inspired the focus of this paper: the constant radius orbits. When black hole spins are misaligned, the constant radius orbits are not circles but rather lie on the surface of a sphere and have acquired the name "spherical orbits". The spherical orbits are significant as they energetically frame the distribution of all orbits. In addition, each unstable spherical orbit is asymptotically approached by an orbit that whirls an infinite number of times, known as a homoclinic orbit. A homoclinic trajectory is an infinite whirl limit of the zoom-whirl spectrum and has a further significance as the separatrix between inspiral and plunge for eccentric orbits. We work in the context of two spinning black holes of comparable mass as described in the 3PN Hamiltonian with spin-orbit coupling included. As such, the results could provide a testing ground of the accuracy of the PN expansion. Further, the spherical orbits could provide useful initial data for numerical relativity. Finally, we comment that the spinning black hole pairs should give way to chaos around the homoclinic orbit when spin-spin coupling is incorporated.Comment: 16 pages, several figure

    B -> pi pi, New Physics in B -> pi K and Implications for Rare K and B Decays

    Full text link
    The measured B -> pi pi, pi K branching ratios exhibit puzzling patterns. We point out that the B -> pi pi hierarchy can be nicely accommodated in the Standard Model (SM) through non-factorizable hadronic interference effects, whereas the B -> pi K system may indicate new physics (NP) in the electroweak (EW) penguin sector. Using the B -> pi pi data and the SU(3) flavour symmetry, we may fix the hadronic B -> pi K parameters, which allows us to show that any currently observed feature of the B -> pi K system can be easily explained through enhanced EW penguins with a large CP-violating NP phase. Restricting ourselves to a specific scenario, where NP enters only through Z^0 penguins, we derive links to rare K and B decays, where an enhancement of the K_L-> pi^0 nu nu_bar rate by one order of magnitude, with BR(K_L -> pi^0 nu nu_bar) > BR(K^+ -> pi^+ nu nu_bar), BR(K_L -> pi^0 e^+ e^-)=O(10^{-10}), (\sin2\beta)_{pi nu nu_bar} K* mu^+ mu^-, are the most spectacular effects. We address also other rare K and B decays, epsilon'/epsilon and B_d -> phi K_S.Comment: 6 pages, LaTeX, reference added and a few typos correced, to appear in Physical Review Letter

    N-body decomposition of bipartite networks

    Get PDF
    In this paper, we present a method to project co-authorship networks, that accounts in detail for the geometrical structure of scientists collaborations. By restricting the scope to 3-body interactions, we focus on the number of triangles in the system, and show the importance of multi-scientists (more than 2) collaborations in the social network. This motivates the introduction of generalized networks, where basic connections are not binary, but involve arbitrary number of components. We focus on the 3-body case, and study numerically the percolation transition.Comment: 5 pages, submitted to PR

    Constraining the CKM Parameters using CP Violation in semi-leptonic B Decays

    Get PDF
    We discuss the usefulness of the CP violating semi-leptonic asymmetry a_{SL} not only as a signal of new physics, but also as a tool in constraining the CKM parameters. We show that this technique could yield useful results in the first years of running at the B factories. We present the analysis graphically in terms of M_{12}, the dispersive part of the B-Bbar mixing amplitude. This is complementary to the usual unitarity triangle representation and often allows a cleaner interpretation of the data.Comment: 15 pages REVTEX, 7 figure

    CP Asymmetry in B_d --> phi K_S: Standard Model Pollution

    Full text link
    The difference in the time dependent CP asymmetries between the modes B>psiKSB --> psi K_S and B>phiKSB --> phi K_S is a clean signal for physics beyond the Standard Model. This interpretation could fail if there is a large enhancement of the matrix element of the b>uubarsb --> u ubar s operator between the BdB_d initial state and the phiKSphi K_S final state. We argue against this possibility and propose some experimental tests that could shed light on the situation.Comment: 9 pages, Revte
    corecore