896 research outputs found

    Predictions with Lattice QCD

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    In recent years, we used lattice QCD to calculate some quantities that were unknown or poorly known. They are the q2q^2 dependence of the form factor in semileptonic D→KlÎœD\to Kl\nu decay, the leptonic decay constants of the D+D^+ and DsD_s mesons, and the mass of the BcB_c meson. In this paper, we summarize these calculations, with emphasis on their (subsequent) confirmation by measurements in e+e−e^+e^-, Îłp\gamma p and pˉp\bar{p}p collisions.Comment: 5 pages; update of hep-lat/0509169, with experimental confirmation of form factors from Belle and fDs from BaBar; presented at SciDAC 2006 for the Fermilab Lattice, MILC, and HPQCD Collaboration

    Probing Yukawa Unification with K and B Mixing

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    We consider corrections to the unification of down-quark and charged-lepton Yukawa couplings in supersymmetric GUTs, which links the large nu_tau-nu_mu mixing angle to b -> s transitions. These corrections generically occur in simple grand-unified models with small Higgs representations and affect s -> d and b -> d transitions via the mixing of the corresponding right-handed superpartners. On the basis of a specific SUSY-SO(10) model, we analyze the constraints from K-Kbar and B-Bbar mixing on the additional \tilde{d}_R-\tilde{s}_R rotation angle theta. We find that epsilon_K already sets a stringent bound on theta, theta^{max}=O(1 degree), indicating a very specific flavor structure of the correction operators. The impact of the large neutrino mixings on the unitarity triangle analysis is also briefly discussed, as well as their ability to account for the sizeable CP-violating phase observed recently in B_s -> psi phi decays.Comment: 19 pages. Discussion in Sec. 5.2 slightly extended; minor numerical modifications in Secs. 5.1 to 5.4, conclusions unchanged. Version to appear in JHE

    Study of high temperature and high density plasmoids in axially symmetrical magnetic fields

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    Within the framework of an Institutional Partnership of the Alexander von Humboldt Foundation, the Budker Institute of Nuclear Physics Novisibirsk (BINP) and Forschungszentrum Dresden-Rossendorf worked together in a joint project devoted to the research at the coupled GDT-SHIP facility of the BINP with the focus on the study of plasma phenomena within the SHIP mirror section. The project began at July 1st, 2005 and ended on August 30th, 2008. It included work packages of significant theoretical, computational and analyzing investigations. The focus of this final report is on the presentation of results achieved whereas the work that was done is described briefly only. Chapter 2 illustrates the GDT-SHIP facility and describes shortly the planned topics of the SHIP plasma research. Chapter 3 explains the main extensions and modifications of the Integrated Transport Code System (ITCS) which were necessary for the calculations of the fast ion and neutral gas particle fields in SHIP, describes briefly the scheme of computations and presents significant results of pre-calculations from which conclusions were drawn regarding the experimental program of SHIP. In chapter 4, the theoretical and computational investigations of self-organizing processes in two-component plasmas of the GDT-SHIP device are explained and the results hitherto achieved are presented. In chapter 5, significant results of several experiments with moderate and with enhanced plasma parameters are presented and compared with computational results obtained with the ITCS. Preparing neutron measurements which are planned for neutron producing experiments with deuterium injection, Monte Carlo neutron transport calculations with the MCNP code were also carried out. The results are presented. Finally, from the results obtained within the joint research project important conclusions are drawn in chapter 6

    The CKM Matrix and The Unitarity Triangle: Another Look

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    The unitarity triangle can be determined by means of two measurements of its sides or angles. Assuming the same relative errors on the angles (α,ÎČ,Îł)(\alpha,\beta,\gamma) and the sides (Rb,Rt)(R_b,R_t), we find that the pairs (Îł,ÎČ)(\gamma,\beta) and (Îł,Rb)(\gamma,R_b) are most efficient in determining (ϱˉ,ηˉ)(\bar\varrho,\bar\eta) that describe the apex of the unitarity triangle. They are followed by (α,ÎČ)(\alpha,\beta), (α,Rb)(\alpha,R_b), (Rt,ÎČ)(R_t,\beta), (Rt,Rb)(R_t,R_b) and (Rb,ÎČ)(R_b,\beta). As the set \vus, \vcb, RtR_t and ÎČ\beta appears to be the best candidate for the fundamental set of flavour violating parameters in the coming years, we show various constraints on the CKM matrix in the (Rt,ÎČ)(R_t,\beta) plane. Using the best available input we determine the universal unitarity triangle for models with minimal flavour violation (MFV) and compare it with the one in the Standard Model. We present allowed ranges for sin⁥2ÎČ\sin 2\beta, sin⁥2α\sin 2\alpha, Îł\gamma, RbR_b, RtR_t and ΔMs\Delta M_s within the Standard Model and MFV models. We also update the allowed range for the function FttF_{tt} that parametrizes various MFV-models.Comment: "published version. few typos corrected, results unchanged

    B Physics at the Tevatron: Run II and Beyond

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    This report provides a comprehensive overview of the prospects for B physics at the Tevatron. The work was carried out during a series of workshops starting in September 1999. There were four working groups: 1) CP Violation, 2) Rare and Semileptonic Decays, 3) Mixing and Lifetimes, 4) Production, Fragmentation and Spectroscopy. The report also includes introductory chapters on theoretical and experimental tools emphasizing aspects of B physics specific to hadron colliders, as well as overviews of the CDF, D0, and BTeV detectors, and a Summary.Comment: 583 pages. Further information on the workshops, including transparencies, can be found at the workshop's homepage: http://www-theory.lbl.gov/Brun2/. The report is also available in 2-up http://www-theory.lbl.gov/Brun2/report/report2.ps.gz or chapter-by-chapter http://www-theory.lbl.gov/Brun2/report

    Experimental study of direct photon emission in K- --> pi- pi0 gamma decay using ISTRA+ detector

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    The branching ratio in the charged-pion kinetic energy region of 55 to 90 MeV for the direct photon emission in the K- --> pi- pi0 gamma decay has been measured using in-flight decays detected with the ISTRA+ setup operating in the 25 GeV/c negative secondary beam of the U-70 PS. The value Br(DE)=[0.37+-0.39(stat)+-0.10(syst)]*10^(-5) obtained from the analysis of 930 completely reconstructed events is consistent with the average value of two stopped-kaon experiments, but it differs by 2.5 standard deviations from the average value of three in-flight-kaon experiments. The result is also compared with recent theoretical predictions.Comment: 13 pages, 8 figure

    Measurement of the top quark mass with the Collider Detector at Fermilab

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