3,094 research outputs found

    Topological Electropoles in 4+1 Dimensional EYMCS Theory

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    A class of explicit exact solutions of Einstein Yang Mills Chern Simons (EYMCS) theory corresponding to topological solitons carrying non-Abelian topological electric charge is obtained. This verifies a conjecture made in Ref.[1,2] regarding the stabilization of the corresponding charged configurations in the theory without gravity .Comment: 11 pages ,Plain TeX,IOPB/BBSR/94-11. Minor typos in eqns(4),(7), (13a),(13b),(21) correcte

    Topological Soliton Multiplets in 4+1 Dimensional YMCS Theory

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    We generalize our results1{}^1 on charged topological solitons (CTS) in 4+14+1 dimensional SU(3)SU(3) Yang-Mills-Chern-Simons (YMCS) theory to SU(N)SU(N). The SU(N)SU(N) multiplet structure of two classes of solitons associated with the maximal embeddings SU(2)×U(1)N2SU(N)SU(2)\times U(1)^{N-2}\subset SU(N) and SO(3)×U(1)N3SU(N)SO(3)\times U(1)^{N-3}\subset SU(N) and the vital role of the SU(N)SU(N) multiplet of topological currents is clarified. In the case of the first embedding one obtains a NC2^{N}C_{2}-plet of CTS. In the second, for N=3N = 3, one obtains neutral solitons which, though (classically) spinless, have magnetic moments. For N4N \geq 4, after modding out the above mentioned non-particulate feature, one obtains NC3^{N}C_{3} plets of CTS.Comment: (minor semantic changes), 21

    Proton decay matrix elements with domain-wall fermions

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    Hadronic matrix elements of operators relevant to nucleon decay in grand unified theories are calculated numerically using lattice QCD. In this context, the domain-wall fermion formulation, combined with non-perturbative renormalization, is used for the first time. These techniques bring reduction of a large fraction of the systematic error from the finite lattice spacing. Our main effort is devoted to a calculation performed in the quenched approximation, where the direct calculation of the nucleon to pseudoscalar matrix elements, as well as the indirect estimate of them from the nucleon to vacuum matrix elements, are performed. First results, using two flavors of dynamical domain-wall quarks for the nucleon to vacuum matrix elements are also presented to address the systematic error of quenching, which appears to be small compared to the other errors. Our results suggest that the representative value for the low energy constants from the nucleon to vacuum matrix elements are given as |alpha| simeq |beta| simeq 0.01 GeV^3. For a more reliable estimate of the physical low energy matrix elements, it is better to use the relevant form factors calculated in the direct method. The direct method tends to give smaller value of the form factors, compared to the indirect one, thus enhancing the proton life-time; indeed for the pi^0 final state the difference between the two methods is quite appreciable.Comment: 56 pages, 17 figures, a comment and two references added in the introduction, typo corrected in Eq.1

    A new window on Strange Quark Matter as the ground state of strongly interacting matter

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    If strange quark matter is the true ground state of matter, it must have lower energy than nuclear matter. Simultaneously, two-flavour quark matter must have higher energy than nuclear matter, for otherwise the latter would convert to the former. We show, using an effective chiral lagrangian, that the existence of a new lower energy ground state for two-flavour quark matter, the pion condensate, shrinks the window for strange quark matter to be the ground state of matter and sets new limits on the current strange quark mass

    A Study of Morris-Thorne Wormhole in Einstein-Cartan Theory

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    This paper focuses on the Einstein-Cartan theory, an extension of general relativity that incorporates a torsion tensor into spacetime. The differential form technique is employed to analyze the Einstein-Cartan theory, which replaces tensors with tetrads. A tetrad formalism, specifically the Newmann-Penrose-Jogia-Griffiths formalism, is used to study the field equations. The energy-momentum tensor is also determined, considering a Weyssenhoff fluid with anisotropic matter. The spin density is derived in terms of the red-shift function. We also examine the energy conditions at the throat of a Morris-Thorne wormhole. The results shed light on the properties of wormholes in the context of the Einstein-Cartan theory, including the energy conditions at the throat.Comment: 20 pages, 3 figures, 1 table. Preparing for submission to the International Journal of Geometric Methods in Modern Physic

    Anomalous Thermoelectric power of over-doped Bi2Sr2CaCu2O8 superconductor

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    Temperature dependence of thermoelectric power S(T) of three differently processed Bi2Sr2CaCu2O8 (Bi2212) samples, viz. as-processed melt quenched (Bi2212-MQ), 6000C N2-annealed (Bi2212-N2) and 6000C O2-annealed (Bi2212-O2) is reported here. All the samples possess single-phase character and their superconducting transition temperatures (TcR=0) are 85 K, 90 K and 72 K respectively for Bi2212-MQ, Bi2212-N2 and Bi2212-O2. While Bi2212-MQ and Bi2212-N2 samples are in near optimum doping regime, Bi2212-O2 is an over-doped sample. TcS=0 values obtained through S(T) data are also in line with those deduced from the temperature dependence of resistance and DC magnetization. Interestingly, S(T) behaviour of the optimally-doped Bi2212-MQ and Bi2212-N2 samples is seen to be positive in whole temperature range, it is found negative for the over-doped Bi2212-O2 sample above TcS=0. These results have been seen in the light of the recent band structure calculations and the ensuing split Fermi surface as determined by angle-resolved photoelectron spectroscopy (ARPES).Comment: 11 Pages Text + Figs: comments welcome ([email protected]

    Proton lifetime bounds from chirally symmetric lattice QCD

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    We present results for the matrix elements relevant for proton decay in Grand Unified Theories (GUTs). The calculation is performed at a fixed lattice spacing a^{-1}=1.73(3) GeV using 2+1 flavors of domain wall fermions on lattices of size 16^3\times32 and 24^3\times64 with a fifth dimension of length 16. We use the indirect method which relies on an effective field theory description of proton decay, where we need to estimate the low energy constants, \alpha = -0.0112(25) GeV^3 and \beta = 0.0120(26) GeV^3. We relate these low energy constants to the proton decay matrix elements using leading order chiral perturbation theory. These can then be combined with experimental bounds on the proton lifetime to bound parameters of individual GUTs.Comment: 17 pages, 9 Figure

    Correlation Functions of Hadron Currents in the QCD Vacuum Calculated in Lattice QCD

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    Point-to-point vacuum correlation functions for spatially separated hadron currents are calculated in quenched lattice QCD on a 163×2416^3\times 24 lattice with 6/g2=5.76/g^2=5.7. The lattice data are analyzed in terms of dispersion relations, which enable us to extract physical information from small distances where asymptotic freedom is apparent to large distances where the hadronic resonances dominate. In the pseudoscalar, vector, and axial vector channels where experimental data or phenomenological information are available, semi-quantitative agreement is obtained. In the nucleon and delta channels, where no experimental data exist, our lattice data complement experiments. Comparison with approximations based on sum rules and interacting instantons are made, and technical details of the lattice calculation are described.Comment: 31 pages in REVTeX (with 10 figures to be added using figures command), MIT CTP #214

    Lattice Calculation of Point-to-Point Hadron Current Correlation

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    Point-to-point correlation functions of hadron currents in the QCD vacuum are calculated on a lattice and analyzed using dispersion relations, providing physical information down to small spatial separations. Qualitative agreement with phenomenological results is obtained in channels for which experimental data are available, and these correlation functions are shown to be useful in exploring approximations based on sum rules and interacting instantons.Comment: 11 page

    Does J/ψπ+πJ/\psi \rightarrow \pi^{+} \pi^{-} fix the Electromagnetic Form Factor Fπ(t)F_{\pi}(t) at t=MJ/ψ2t=M_{J/\psi}^2?

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    We show that the J/ψπ+πJ/\psi \rightarrow \pi^{+} \pi^{-} decay is a reliable source of information for the electromagnetic form factor of the pion at t=MJ/ψ2=9.6GeV2t=M_{J/\psi}^2=9.6 {\rm GeV}^2 by using general arguments to estimate, or rather, put upper bounds on, the background processes that could spoil this extraction. We briefly comment on the significance of the resulting Fπ(MJ/ψ2)F_{\pi}(M_{J/\psi}^2).Comment: 10 pages revtex manuscript, one figure--not included, U. of MD PP #94-00
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