7,313 research outputs found

    Pathological phenomena in Denjoy-Carleman classes

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    Let CM\mathcal C^M denote a Denjoy-Carleman class of C∞\mathcal C^\infty functions (for a given logarithmically-convex sequence M=(Mn)M = (M_n)). We construct: (1) a function in CM((−1,1))\mathcal C^M((-1,1)) which is nowhere in any smaller class; (2) a function on R\mathbb R which is formally CM\mathcal C^M at every point, but not in CM(R)\mathcal C^M(\mathbb R); (3) (under the assumption of quasianalyticity) a smooth function on Rp\mathbb R^p (p≄2p \geq 2) which is CM\mathcal C^M on every CM\mathcal C^M curve, but not in CM(Rp)\mathcal C^M(\mathbb R^p).Comment: 21 page

    Nano-scale oxygen octahedral tilting in 0.90(Bi1/2Na1/2)TiO3-0.05(Bi1/2K1/2)TiO3-0.05BaTiO3 lead-free perovskite piezoelectric ceramics

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    The oxygen octahedral tilted domains in 0.90(Bi1/2Na1/2)TiO3-0.5(Bi1/2K1/2)TiO3-0.5BaTiO3 lead-free perovskite piezoelectric ceramic have been studied by transmission electron microscopy (TEM). Selected-area electron diffraction patterns shows the 1/2ooo and 1/2ooe reflections, indicating the presence of antiphase (a-a-a-) and in-phase (aoaoc+) octahedral tilting, respectively. The morphology and distributions of these tilted domains are shown in the centered dark-field images. Further, the Bragg-filtered high-resolution TEM image reveals that the size of the in-phase tilted domains varies from 1 to 8 nm across. The ceramic contains the mixture of non-tilted and variants of the antiphase and in-phase tilted domains.Comment: 12 pages, 3 figure

    A_{LT} in the polarized Drell-Yan process at RHIC and HERA energies

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    We present a leading order (LO) estimate for the longitidinal-transverse spin asymmetry (A_{LT}) in the nucleon-nucleon polarized Drell-Yan process at RHIC and HERA-N⃗\vec{N} energies in comparison with A_{LL} and A_{TT}. A_{LT} receives contribution from g_1, the transversity ditribution h_1, and the twist-3 distributions g_T and h_L. For the twist-3 contribution we use the bag model prediction evolved to a high energy scale by the large-N_c evolution equation. We found that A_{LT} (normalized by the asymmetry in the parton level) is much smaller than the corresponding A_{TT}. Twist-3 contribution given by the bag model also turned out to be negligible.Comment: 12 pages in Latex. 5 figures included as eps files using epsbox.sty. Minor corrections for typos and notations incorporate

    A Thin HI Circumnuclear Disk in NGC4261

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    We report on high sensitivity, spectral line VLBI observations of the HI absorption feature in the radio galaxy NGC4261. Although absorption is only detectable on the most sensitive baseline, it can be unambiguously associated with the counterjet and is interpreted to originate in a thin atomic circumnuclear disk. This structure is probably a continuation of the dusty accretion disk inferred from HST imaging, which could be feeding the massive black hole. HI column densities in front of the counterjet of the order of 10^{21}(T_sp/100 K) cm^{-2} are derived, consistent with X-ray data and VLBI scale free-free absorption. The data presented here are the result of the first scientific project processed on the new EVN MkIV data processor.Comment: 4 pages, 3 postscript figures, Astronomy and Astrophysics Letters, in pres

    Chiral-Odd Contribution to Single-Transverse Spin Asymmetry in Hadronic Pion Production

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    A formula for the single transverse spin asymmetry in the large-pTp_T pion production in the nucleon-nucleon collision is derived. We focuss on the chiral-odd contribution where the transversity distribution and the chiral-odd spin-independent twist-3 distribution contributes. This contribution is expected to give rise to a large effect at xF→−1x_F\to -1.Comment: Latex file 10 pages + 2 figures attached as PS and EPS files. A minor correction is include

    Charmed Strange Pentaquarks in the Large NcN_c Limit

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    The properties of pentaquarks containing a heavy anti-quark and strange quarks are studied in the bound state picture. In the flavor SU(3) limit, there are many pentaquark states with the same binding energy. When the SU(3) symmetry breaking effects are included, however, three states become particularly stable due to a ``Gell-Mann--Okubo mechanism''. They are the Qˉsuud\bar Qsuud and Qˉsudd\bar Qsudd states discussed by Lipkin, and a a previously unstudied Qˉssud\bar Qssud state. These states will have JP=12+J^P={1\over2}^+ and their masses are estimated. These states, if exist, may be seen in experiments in the near future.Comment: 12 pages in REVTeX, no figure

    Target mass corrections to matrix elements in nucleon spin structure functions

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    Target mass corrections to the twist-4 terms f~2p,n,d\tilde f_2^{p,n,d} as well as to the leading-twist a~2\tilde a_2 are discussed.Comment: 7 pages and 2 figure

    The nonperturbative origin of delta-function singularity in the chirally-odd twist-3 distribution function e(x)

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    We analytically prove that the existence of the delta-function singularity in the chirally-odd twist-3 distribution e(x)e(x) of the nucleon is inseparably connected with the nonvanishing quark condensate as a signal of the spontaneous chiral symmetry breaking of the QCD vacuum. This singularity in e(x)e(x), which would be observed as a sizable violation of the 1st moment sum rule, is then interpreted as giving a very rare case that the nontrivial vacuum structure of QCD manifests in an observable of a localized QCD excitation, i.e. the nucleon.Comment: 9 pages, 1 eps-figur
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