共查询到20条相似文献,搜索用时 15 毫秒
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M. Grady 《Zeitschrift fur Physik C Particles and Fields》1988,39(1):125-136
High precision data from a variety of sources forSU(2) andSU(3) Wilson action lattice gauge theory are analyzed with respect to the hypothesis of the possible existence of a zero temperature deconfining phase transition, in analogy with theU(1) theory. The internal energy, specific heat, string tension, and Wilson line, fit well to correlation length scaling laws associated with a finite order transition occurring at the weak coupling end of the crossover region for both theories. TheSU(2) theory is consistent with a correlation length exponent ν=2/3 and critical pointβ c ≈2.47. ForSU(3) the data fit well to ν=1 andβ c ≈6.69. Additional indirect evidence for the existence of such phase transitions is discussed, as is the possible crucial role of light dynamical fermions in the confinement mechanism. 相似文献
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J.P. Ader 《Nuclear Physics B》1975,98(1):154-172
On the basis of the “b universality” hypothesis, Regge behaviour and SU(3) symmetry, we discuss processes of the type at backward angles when significant data are available. Related annihilation processes by line-reversal are also studied and duality constraints are taken into account. On the whole a satisfactory scheme seems to emerge. 相似文献
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《Nuclear Physics B》1988,298(4):653-672
For the six-gluon scattering process we give explicit and simple expressions for the amplitude and its square. To achieve this we use an analogy with string theories to identify a unique procedure for writing the multi-gluon scattering amplitudes in terms of a sum of gauge invariant dual sub-amplitudes multiplied by an appropriate color (Chan-Paton) factor. The sub-amplitudes defined in this way are invariant under cyclic permutations, satisfy powerful identities which relate different non-cyclic permutations and factorize in the soft gluon limit, the two-gluon collinear limit and on multi-gluon poles. Also, to leading order in the number of colors these sub-amplitudes sum incoherently in the square of the full matrix element. The results contained here are important for Monte Carlo studies of multi-processes at hadron colliders as well as for understanding the general structure of QCD. 相似文献
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《Nuclear Physics B》1996,463(1):99-157
I demonstrate that the leading logarithms for high-energy scattering can be obtained as a result of evolution of the non-local operators—straight-line ordered gauge factors—with respect to the slope of the straight line. 相似文献
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J. Bernabeu B. Desplanques J. Navarro S. Noguera 《Zeitschrift fur Physik C Particles and Fields》1990,46(2):323-328
The amplitude for ββ decay with 2ν emission is shown to be related to (p,n) and (n,p) reactions on the initial and final states, respectively. The suppression of both ββ and (n,p) reaction is connected, and its origin is discussed by referring to theSU(4) symmetry. From present data on the first ones, we estimate the forward (n, p) strength of relevance for the ββ problem. The interest of the experimental determination of this strength is emphasized. Assuming a perturbative breaking of theSU(4) symmetry, results are given for76Ge,82Se,128Te and130Te. 相似文献
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In the Interacting Boson-Fermion-Fermion Model (IBFFM) for odd-odd nuclei the yrast states are calculated for \(\tilde j_\pi = \tilde h_{1 1/2} ,\tilde j_v = \tilde i_{1 3/2} \) , proton-neutron configurations coupled to theO(6) andSU(3) boson core. The results are discussed in terms of the strongly coupled/ decoupled band type criterion and in comparison to the peaceful and conflicting case of asymmetric rotor model. 相似文献
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The magnetic dipole solutions of Sikivie and Weiss are considered with the addition of a magnetic source and the validity of the observation that for large source strengths the energy of such solutions is lower than the energy of corresponding Coulomb solutions is examined. It is found that the presence of electric and magnetic sources leads to dipole solutions and that the introduction of a magnetic source does not alter the relationship between their energy and the energy of corresponding Coulomb solutions. 相似文献
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M. H. Urin 《Physics of Atomic Nuclei》2010,73(8):1384-1389
A formulation of the particle-hole optical model is proposed for describing the contribution of the fragmentation effect to
the formation of strength functions for high-energy giant resonances. The model is based on the Bethe-Goldstone equation for
the energy-averaged particle-hole Green’s function. In this equation, the particle-hole interaction that is induced by a virtual
excitation of multiquasiparticle configurations and in which, upon averaging over energy, an imaginary part is contained is
taken into account. An analogy with the single-quasiparticle optical model is discussed. 相似文献
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The surface electronic structure of platinum is investigated by photoemission using extreme ultraviolet light. High-order harmonics of amplified femtosecond Ti:sapphire radiation in the range h=20 to 50eV are employed. In the normal emission spectra of Pt(111), three well-distinguished maxima at fixed kinetic energies of Ekin=10,12.5 and 19eV are observed. These structures, which are far above the Fermi energy, show a strong dependence upon adsorption of CO. This observation and layer-resolved photoemission calculations indicate the surface character of the involved unoccupied platinum states. These empty states are populated by the primary photo-excited electrons, which decay into the unoccupied states due to inelastic scattering. The pronounced emission of the electrons originates mainly from these surface resonances. PACS 79.60.-i; 42.65.Ky; 71.20.-b; 79.20.Hx; 79.60.Dp 相似文献
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Experimental data are presented for the scattering of cold electrons by CS2, for both integral and backward scattering, between a few meV and a few hundred meV impact energy. Giant resonances with cross sections in excess of 50 A(2) are observed below 100 meV, associated with the transient formation of CS(-)(2) at 15 meV and with the bend and symmetric stretch of CS(2) at thresholds of 49 and 82 meV, respectively. The resonance at 49 meV is 2 orders of magnitude greater in cross section than a dipole impulsive model predicts. These structures are superimposed on a sharp rise in the scattering cross section at low energy, which may be attributed to virtual state scattering. 相似文献
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Derro DJ Hudson EW Lang KM Pan SH Davis JC Markert JT de Lozanne AL 《Physical review letters》2002,88(9):097002
We present scanning tunneling spectroscopy measurements of the CuO chain plane in YBa(2)Cu(3)O(6+x), showing an approximately 25 meV gap in the local density of states (LDOS) filled by numerous intragap resonances: intense peaks in LDOS spectra associated with one-dimensional, Friedel-like oscillations. We discuss how these phenomena shed light on recent results from other probes, as well as their implications for phenomena in the superconducting CuO(2) plane. 相似文献
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Werner Nahm 《Communications in Mathematical Physics》1988,118(1):171-176
Due to the Cappelli-Itzykson-Zuber classification, the minimal conformally invariant quantum field theories withSU(2) currents are classified by the ADE Lie algebras. Here I give a conceptual proof of the empirically valid relation between their partition functions and the Lie algebra exponents. 相似文献
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Using fits to the available data on the pion and deuteron electromagnetic form factors and the Chou-Yang model, the computed
values of differential cross-sections for high-energy pion-deuteron elastic scattering agree reasonably well with the available
experimental data. Whereas only a shoulder is expected to appear up to energies of several hundreds of GeV, a dip and a secondary
maximum are predicted to be conspicuous only forP
lab≫400 GeV/C. The position of the dip starts at a much lower value, |t
d| ≅ 0.5–0.6 GeV2, as compared to the corresponding position in thepp scattering. The positions of the first dip are plotted against total cross-section which can be verified by future high-energy
experiments. Limitations of the model predictions for ultrahigh energies are pointed out. 相似文献
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K. Ishikawa A. Sato G. Schierholz M. Teper 《Zeitschrift fur Physik C Particles and Fields》1983,21(1):167-188
We calculate the glueball mass spectrum in theSU (3) lattice regularized gauge theory. We find fourlight glueballs: the 0++, 2++, 0?+ and, most interestingly from the experimental point of view, the oddball 1?+. We calculate the 0++ and 2++ masses over a range of β values and find thatboth states conform to continuum renormalization group behaviour to a very significant degree. The question of metastable states and temperature is addressed in detail. Finally we discuss and resolve contrary claims in the recent literature. 相似文献