1,432 research outputs found

    Elliptic aspects of statistical mechanics on spheres

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    Our earlier results on the temperature inversion properties and the ellipticisation of the finite temperature internal energy on odd spheres are extended to orbifold factors of odd spheres and then to other thermodynamic quantities, in particular to the specific heat. The behaviour under modular transformations is facilitated by the introduction of a modular covariant derivative and it is shown that the specific heat on any odd sphere can be expressed in terms of just three functions. It is also shown that the free energy on the circle can be written elliptically.Comment: 22 pages. JyTe

    Sensitization of tumour cells to lysis by virus-specific CTL using antibody-targeted MHC class I/peptide complexes

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    A number of cell surface molecules with specificity to tumour cells have been identified and monoclonal antibodies (mAb) to some of these antigens have been used for targeting tumour cells in vivo. We have sought to link the powerful effector mechanisms of cytotoxic T-cells with the specificity of mAb, by targeting recombinant HLA class I molecules to tumour cells using an antibody delivery system. Soluble recombinant MHC class I/peptide complexes including HLA-A2.1 refolded around an immunodominant peptide from the HIV gag protein (HLA-A2/gag) were synthesized, and the stability of these complexes at 37°C was confirmed by enzyme-linked immunosorbent assay using a conformation-specific antibody. MHC class I-negative lymphoma cells (Daudi) were labelled with a biotinylated mAb specific for a cell surface protein (anti-CD20) then linked to soluble biotinylated HLA-A2/gag complexes using an avidin bridge. Flow cytometry revealed strong labelling of lymphoma cells with HLA-A2/gag complexes (80-fold increase in mean channel fluorescence). CTL specific for HLA-A2/gag efficiently lysed complex-targeted cells, while control CTL (specific for an HLA-A2.1-restricted epitope of melan-A) did not. Similarly, SK-mel-29 melanoma cells were also efficiently lysed by HLA-A2/gag-specific CTL when HLA-A2/gag complexes were linked to their surface via the HMW-MAA specific anti-melanoma antibody 225.28s. With further consideration to the in vivo stability of the MHC class I/peptide complexes, this system could prove a new strategy for the immunological therapy of cancer. © 2000 Cancer Research Campaig

    Metallic Xenon, Molecular Condensates, and Superconductivity

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    A possibility of explaining the light absorption observed to occur under pressure-induced xenon metallization as due to the transition to the superconducting state is analyzed. The mechanism of the van der Waals bonding is discussed.Comment: LaTeX 2.09 (RevTeX), 4 pages, 4 PostScript figures included in tex

    Theoretical Studies of Spectroscopy and Dynamics of Hydrated Electrons.

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    First Observation of Υ(1S)γππ\Upsilon(1S)\to \gamma\pi\pi

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    We report on a study of exclusive radiative decays of the Upsilon(1S) resonance collected with the CLEO-II detector operating at CESR. We present the first observation of the radiative decays Upsilon(1S)->gamma pi+pi- and Upsilon(1S)->gamma pi0pi0. For the dipion mass regime m(pipi)>1.0 GeV, we obtain Br(Upsilon(1S)->gamma pi+pi-=(6.3+/-1.2+/-1.3) x 10^(-5), and Br(Upsilon(1S)->gamma pi0pi0=(1.7+/-0.6+/-0.3) x 10^(-5). The observed gamma pipi events are consistent with the hypothesis Upsilon(1S)->gamma f2(1270).Comment: 9 pages, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Study of 3-prong Hadronic τ\tau Decays with Charged Kaons

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    Using a sample of 4.7/fb integrated luminosity accumulated with the CLEO-II detector at the Cornell Electron Storage Ring (CESR), we have measured the branching fractions of the tau lepton into Kh+πντK^- h^+ \pi^- \nu_\tau and KK+πντK^- K^+ \pi^- \nu_\tau relative to hh+hντ;Kh+ππ0ντh^- h^+ h^- \nu_\tau; K^- h^+ \pi^- \pi^0\nu_\tau and KK+ππ0ντK^- K^+ \pi^- \pi^0\nu_\tau relative to hh+hπ0ντh^- h^+ h^- \pi^0 \nu_\tau. The relative branching fractions are: (5.16+-0.20+-0.50)*10210^{-2}, (1.52+-0.14+-0.29)*10210^{-2}, (2.54+-0.44+-0.39)*10210^{-2} and <0.0154<0.0154 at 95% C.L., respectively. Coupled with additional experimental information, we use our results to extract information on the structure of three-prong tau decays to charged kaons.Comment: 16 pages postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Further Search for the Two-Photon Production of the Glueball Candidate fJ(2220)f_{J}(2220)

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    The CLEOII detector at the Cornell e+ e- storage ring CESR has been used to search for the two-photon production of the fJ(2220)f_J(2220) decaying into pi+ pi-. No evidence for a signal is found in data corresponding to an integrated luminosity of 4.77/fb and a 95% CL upper limit on ΓtwophotonBRpi+pi\Gamma_{two-photon} * BR{pi+ pi-} of 2.5 eV is set. If this result is combined with the BES Collaboration's measurement of fJ(2220)>pi+pif_J(2220) -> pi+ pi- in radiative J/ψJ/\psi decay, a 95% CL lower limit on the stickiness of the fJ(2220)f_J(2220) of 73 is obtained. If the recent CLEO result for \Gamma_{two-photon} * BR{\K_S K_S} is combined with the present result, the stickiness of the fJ(2220)f_J(2220) is found to be larger than 102 at the 95% CL. These results for the stickiness (the ratio of the probabilities for two-gluon coupling and two-photon coupling) provide further support for a substantial neutral parton content in the fJ(2220)f_J(2220).Comment: 8 pages, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Flavor-Specific Inclusive B Decays to Charm

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    We have measured the branching fractions for B -> D_bar X, B -> D X, and B -> D_bar X \ell^+ \nu, where ``B'' is an average over B^0 and B^+, ``D'' is a sum over D^0 and D^+, and``D_bar'' is a sum over D^0_bar and D^-. From these results and some previously measured branching fractions, we obtain Br(b -> c c_bar s) = (21.9 ±\pm 3.7)%, Br(b -> s g) K^- \pi^+) = (3.69 ±\pm 0.20)%. Implications for the ``B semileptonic decay problem'' (measured branching fraction being below theoretical expectations) are discussed. The increase in the value of Br(b -> c c_bar s) due to B>DXB -> D X eliminates 40% of the discrepancy.Comment: 12 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Radiative Decay Modes of the D0D^{0} Meson

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    Using data recorded by the CLEO-II detector at CESR we have searched for four radiative decay modes of the D0D^0 meson: D0ϕγD^0\to\phi\gamma, D0ωγD^0\to\omega\gamma, D0KˉγD^0\to\bar{K}^{*}\gamma, and D0ρ0γD^0\to\rho^0\gamma. We obtain 90% CL upper limits on the branching ratios of these modes of 1.9×1041.9\times 10^{-4}, 2.4×1042.4\times 10^{-4}, 7.6×1047.6\times 10^{-4} and 2.4×1042.4\times 10^{-4} respectively.Comment: 15 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN
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