29,019 research outputs found

    On a q-analogue of the multiple gamma functions

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    A qq-analogue of the multiple gamma functions is introduced, and is shown to satisfy the generalized Bohr-Morellup theorem. Furthermore we give some expressions of these function.Comment: 8 pages, AMS-Late

    Implications of a DK Molecule at 2.32 GeV

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    We discuss the implications of a possible quasinuclear DK bound state at 2.32 GeV. Evidence for such a state was recently reported in D_s^+pi^o by the BaBar Collaboration. We first note that a conventional quark model c-sbar assignment is implausible, and then consider other options involving multiquark systems. An I=0 c sbar n nbar baryonium assignment is one possibility. We instead favor a DK meson molecule assignment, which can account for the mass and quantum numbers of this state. The higher-mass scalar c-sbar state expected at 2.48 GeV is predicted to have a very large DK coupling, which would encourage formation of an I=0 DK molecule. Isospin mixing is expected in hadron molecules, and a dominantly I=0 DK state with some I=1 admixture could explain both the narrow total width of the 2.32 GeV state as well as the observed decay to D_s^+ pi^o. Additional measurements that can be used to test this and related scenarios are discussed.Comment: 6 pages, 1 figur

    A Radio Perspective on the Wet Merger Remnant NGC 34

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    We present VLA observations of the neutral hydrogen and radio continuum of NGC 34 (= NGC 17 = Mrk 938). This object is an ideal candidate to study the fate of gas in mergers, since, as shown by an optical study done by Schweizer & Seitzer (2007), it is a gas-rich ("wet") merger remnant of two disk galaxies of unequal mass hosting a strong central starburst and a weak AGN. We detect HI emission from both tidal tails and from nearby galaxies, suggesting that NGC 34 is actually part of a gas-rich group and might have recently interacted with one of its companions. The kinematics of the gas suggests this remnant is forming an outer disk of neutral hydrogen from the gas of the northern tail. We also detect broad HI absorption (514 +/- 21 km/s wide) at both negative and positive velocities with respect to the systemic velocity. This absorption could be explained by the motions of the tidal tails or by the presence of a circumnuclear disk. In addition, we present radio-continuum images that show both nuclear (62.4 +/- 0.3 mJy) and extra-nuclear emission (26.5 +/- 3.0 mJy). The extra-nuclear component is very diffuse and in the shape of two radio lobes, spanning 390 kpc overall. This emission could be a signature of an AGN that has turned off, or it could originate from a starburst-driven superwind. We discuss the possible scenarios that explain our observations, and what they tell us about the location of the gas and the future evolution of NGC 34.Comment: 29 pages, 12 figures, 2 tables. Accepted for publication in the Astronomical Journal. Figs. 1, 2 & 6 degraded to reduce file size

    Bi-layer splitting in overdoped high TcT_{c} cuprates

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    Recent angle-resolved photoemission data for overdoped Bi2212 are explained. Of the peak-dip-hump structure, the peak corresponds the q⃗=0\vec q =0 component of a hole condensate which appears at TcT_c. The fluctuating part of this same condensate produces the hump. The bilayer splitting is large enough to produce a bonding hole and an electron antibonding quasiparticle Fermi surface. Smaller bilayer splittings observed in some experiments reflect the interaction of the peak structure with quasiparticle states near, but not at, the Fermi surface.Comment: 4 pages with 2 figures - published versio

    A bacteriological study of the college creamery milk supply, A case of putrid butter, Purification of milk by the centrifugal separator

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    For several years the Dairy Department has been making experiments in cream ripening and its relation to butter flavor. In the course of this work certain important facts have developed regarding the causes of variation in quality of butter from season to season. It is a fact understood by all buttermakers that under natural conditions, most of the difficulty experienced in securing the right butter flavor Occurs during the winter season. The annual loss to the dairies and creameries of the state due to this fact is undoubtedly very large

    Hyperspherical entanglement entropy

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    The coefficient of the log term in the entanglement entropy associated with hyperspherical surfaces in flat space-time is shown to equal the conformal anomaly by conformally transforming Euclideanised space--time to a sphere and using already existing formulae for the relevant heat--kernel coefficients after cyclic factoring. The analytical reason for the result is that the conformal anomaly on the lune has an extremum at the ordinary sphere limit. A proof is given. Agreement with a recent evaluation of the coefficient is found.Comment: 7 pages. Final revision. Historical comments amended. Minor remarks adde

    The susceptibility and excitation spectrum of (VO)2_2P2_2O7_7 in ladder and dimer chain models

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    We present numerical results for the magnetic susceptibility of a Heisenberg antiferromagnetic spin ladder, as a function of temperature and the spin-spin interaction strengths J⊥J_\perp and J∣∣J_{||}. These are contrasted with new bulk limit results for the dimer chain. A fit to the experimental susceptibility of the candidate spin-ladder compound vanadyl pyrophosphate, (VO)2_2P2_2O7_7, gives the parameters J⊥=7.82J_\perp = 7.82 meV and J∣∣=7.76J_{||} = 7.76 meV. With these values we predict a singlet-triplet energy gap of Egap=3.9E_{gap} = 3.9 meV, and give a numerical estimate of the ladder triplet dispersion relation ω(k)\omega(k). In contrast, a fit to the dimer chain model leads to J1=11.11J_1=11.11 meV and J2=8.02J_2=8.02 meV, which predicts a gap of Egap=4.9E_{gap} = 4.9 meV.Comment: 16 pages, 6 figures available upon request, RevTex 3.0, preprint ORNL-CCIP-94-04 / RAL-94-02
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