709 research outputs found

    Faddeev calculation of a KppK^- p p quasi-bound state

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    We report on the first genuinely three-body KˉNNπΣN{\bar K}NN - \pi \Sigma N coupled-channel Faddeev calculation in search for quasi-bound states in the KppK^- p p system. The main absorptivity in the KpK^- p subsystem is accounted for by fitting to KpK^- p data near threshold. Our calculation yields one such quasi-bound state, with I=1/2I=1/2, Jπ=0J^{\pi}=0^-, bound in the range B5570B \sim 55-70 MeV, with a width of Γ95110\Gamma \sim 95-110 MeV. These results differ substantially from previous estimates, and are at odds with the KppΛpK^- p p \to \Lambda p signal observed by the FINUDA collaboration.Comment: Minor editorial revision; version accepted for publication in Phys. Rev. Let

    STABILITY OF DNA IN PURKINJE CELL NUCLEI OF THE MOUSE : An Autoradiographic Study

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    Neurons of the mouse were labeled with [3H]thymidine during their prenatal period of proliferation. The 3H activity of the Purkinje cell nuclei was then studied autoradiographically 8, 25, 55, and 90 days after birth. The measured grain number per nucleus decreased by about 14% between the 8th and 25th postnatal days and then remained constant up to 90 days. There was no significant decrease of the 3H activity of the Purkinje cell nuclei after correction of the measured grain number per nucleus for increasing nuclear volume of the growing Purkinje cells and for the influence of [3H]β self-absorption in the material of the sections. Injection of a high dose of [3H]thymidine into young adult mice did not result in 3H labeling of either Purkinje or other neurons in other brain regions. The results agree with the concept of metabolic stability of nuclear DNA. "Metabolic" DNA could not be observed in these experiments

    KK^- - nucleus relativistic mean field potentials consistent with kaonic atoms

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    KK^- atomic data are used to test several models of the KK^- nucleus interaction. The t(ρ\rho)ρ\rho optical potential, due to coupled channel models incorporating the Λ\Lambda(1405) dynamics, fails to reproduce these data. A standard relativistic mean field (RMF) potential, disregarding the Λ\Lambda(1405) dynamics at low densities, also fails. The only successful model is a hybrid of a theoretically motivated RMF approach in the nuclear interior and a completely phenomenological density dependent potential, which respects the low density theorem in the nuclear surface region. This best-fit KK^- optical potential is found to be strongly attractive, with a depth of 180 \pm 20 MeV at the nuclear interior, in agreement with previous phenomenological analyses.Comment: revised, Phys. Rev. C in pres

    KˉNN\bar{K}NN quasi-bound state and the KˉN\bar{K}N interaction: coupled-channel Faddeev calculations of the KˉNNπΣN\bar{K}NN - \pi \Sigma N system

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    Coupled-channel three-body calculations of an I=1/2I=1/2, Jπ=0J^{\pi}=0^- KˉNN\bar{K}NN quasi-bound state in the KˉNNπΣN\bar{K}NN - \pi \Sigma N system were performed and the dependence of the resulting three-body energy on the two-body KˉNπΣ\bar{K}N - \pi \Sigma interaction was investigated. Earlier results of binding energy BKpp5070B_{K^-pp} \sim 50 -70 MeV and width ΓKpp100\Gamma_{K^-pp} \sim 100 MeV are confirmed [N.V. Shevchenko {\it et al.}, Phys. Rev. Lett. {\bf 98}, 082301 (2007)]. It is shown that a suitably constructed energy-independent complex KˉN\bar{K}N potential gives a considerably shallower and narrower three-body quasi-bound state than the full coupled-channel calculation. Comparison with other calculations is made.Comment: 22 pages, 7 figures, 4 tables; minor corrections, accepted for publication in Phys. Rev.

    Bernoulli potential in type-I and weak type-II supercoductors: II. Surface dipole

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    The Budd-Vannimenus theorem is modified to apply to superconductors in the Meissner state. The obtained identity links the surface value of the electrostatic potential to the density of free energy at the surface which allows one to evaluate the electrostatic potential observed via the capacitive pickup without the explicit solution of the charge profile.Comment: 7 pages, 1 figur

    Correlated Λd\Lambda d pairs from the KstopAΛdAK^{-}_{stop} A \to \Lambda d A' reaction

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    Correlated Λd\Lambda d pairs emitted after the absorption of negative kaons at rest KstopAΛdAK^{-}_{stop}A\to \Lambda d A' in light nuclei 6Li^6Li and 12C^{12}C are studied. Λ\Lambda-hyperons and deuterons are found to be preferentially emitted in opposite directions. The Λd\Lambda d invariant mass spectrum of 6Li^6Li shows a bump whose mass is 3251±\pm6 MeV/c2^2. The bump mass (binding energy), width and yield are reported. The appearance of a bump is discussed in the realm of the [Kˉ3N\bar{K}3N] clustering process in nuclei. The experiment was performed with the FINUDA spectrometer at DAΦ\PhiNE (LNF).Comment: 13 pages, 5 figures, accepted for publication in Phys. Lett.

    Discontinuity of capacitance at the onset of surface superconductivity

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    The effect of the magnetic field on a capacitor with a superconducting electrode is studied within the Ginzburg-Landau approach. It is shown that the capacitance has a discontinuity at the onset of the surface superconductivity Bc3B_{\rm c3} which is expressed as a discontinuity in the penetration depth of the electric field into metals. Estimates show that this discontinuity is observable with recent bridges for both conventional and high-TcT_{\rm c} superconductors of the type-II

    Negative Kaons in Dense Baryonic Matter

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    Kaon polarization operator in dense baryonic matter of arbitrary isotopic composition is calculated including s- and p-wave kaon-baryon interactions. The regular part of the polarization operator is extracted from the realistic kaon-nucleon interaction based on the chiral and 1/N_c expansion. Contributions of the Lambda(1116), Sigma(1195), Sigma*(1385) resonances are taken explicitly into account in the pole and regular terms with inclusion of mean-field potentials. The baryon-baryon correlations are incorporated and fluctuation contributions are estimated. Results are applied for K- in neutron star matter. Within our model a second-order phase transition to the s-wave K- condensate state occurs at rho_c \gsim 4 \rho_0 once the baryon-baryon correlations are included. We show that the second-order phase transition to the p-wave KK^- condensate state may occur at densities ρc3÷5ρ0\rho_c \sim 3\div 5 \rho_0 in dependence on the parameter choice. We demonstrate that a first-order phase transition to a proton-enriched (approximately isospin-symmetric) nucleon matter with a p-wave K- condensate can occur at smaller densities, \rho\lsim 2 \rho_0. The transition is accompanied by the suppression of hyperon concentrations.Comment: 41 pages, 24 figures, revtex4 styl

    Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at sNN\sqrt{s_{NN}} = 5.02 TeV

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    Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7 <pT,assoc<pT,trig< < p_{\rm{T}, assoc} < p_{\rm{T}, trig} < 5.0 GeV/cc is examined, to include correlations induced by jets originating from low momen\-tum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range η<0.9|\eta|<0.9. The near-side long-range pseudorapidity correlations observed in high-multiplicity p-Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the non-jet-like components. The yields in the jet-like peaks are found to be invariant with event multiplicity with the exception of events with low multiplicity. This invariance is consistent with the particles being produced via the incoherent fragmentation of multiple parton--parton scatterings, while the yield related to the previously observed ridge structures is not jet-related. The number of uncorrelated sources of particle production is found to increase linearly with multiplicity, suggesting no saturation of the number of multi-parton interactions even in the highest multiplicity p-Pb collisions. Further, the number scales in the intermediate multiplicity region with the number of binary nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/161
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