We have calculated some properties of the high-Tc superconductors by using the electron pairing induced by holes model proposed by us recently. The predicted dependence of Tc on the hole concentration δ agrees qualit...
We have calculated some properties of the high-Tc superconductors by using the electron pairing induced by holes model proposed by us recently. The predicted dependence of Tc on the hole concentration δ agrees qualitatively with the experimental data of Shafer et al. [Phys. Rev. B 36, 4047 (1987)]. The dependence of the normalized order parameter and the normalized gap energy on the reduced temperature are very close to the one given by the BCS theory of conventional superconductors. The ratio of the zero-temperature gap energy and Tc is near 1.6. The dependence of the density of states for quasiparticles on energy is found to be asymmetric. The carrier effective mass for 90-K superconductors is ∼4me.
Statistical equilibrium data from a time-ensemble data bank, generated for an anharmonic (15+2)-particle chain [Henry and Grindlay, Phys. Rev. A 38, 2594 (1988)], have been used to calculate coarse-grained distributio...
Statistical equilibrium data from a time-ensemble data bank, generated for an anharmonic (15+2)-particle chain [Henry and Grindlay, Phys. Rev. A 38, 2594 (1988)], have been used to calculate coarse-grained distributions for odd-mode velocities, particle velocities, and nearest-neighbor spring extensions. Each distribution proves to be Maxwellian in form. The mode-velocity temperatures agree with the mode-energy temperatures reported previously (Henry and Grindlay, ibid.). The time-ensemble data were also used to calculate averages and correlation functions for odd-mode energies, odd-mode velocities, particle velocities, spring energies, and their products. The dynamical response of the chain in the statistical equilibrium regime is found to be largely described by the behavior of modes 11, 13, and 15. These modes prove to be strongly correlated. The corresponding averages and correlation functions are calculated for a microcanonical ensemble of eight harmonic oscillators and compared with the time-ensemble results for the chain.
A scaling hypothesis is set up for the magnetization m(T,H;L), susceptibility χ(T,H;L), and correlation length ξ(T,H;L) of a finite-sized system, with O(n) symmetry (n≥2) and long-range interactions decaying as 1/...
A scaling hypothesis is set up for the magnetization m(T,H;L), susceptibility χ(T,H;L), and correlation length ξ(T,H;L) of a finite-sized system, with O(n) symmetry (n≥2) and long-range interactions decaying as 1/rd+σ (0<σ<2), confined to geometry Ld−d’×∞d’ (σ
We consider the process e±p→e±γX. In the first section, we look for radiative zeros and find that they are absent in e−p collisions but possibly observable in e+p collisions. In the second section we inves...
We consider the process e±p→e±γX. In the first section, we look for radiative zeros and find that they are absent in e−p collisions but possibly observable in e+p collisions. In the second section we investigate the effects of the exchange of an extra neutral gauge boson on the process at hand. We find that, given appropriate cuts and using expected luminosities at the DESY ep collider HERA, a 2-standard-deviation effect could arise from a light neutral gauge boson. Z’ masses up to ∼300 GeV/c2 could be probed at the 1-standard-deviation level.
The production of fourth-generation quarks at the Superconducting Super Collider is studied concentrating on event signatures resulting from the single-lepton and two-lepton decay modes. We find that events with multi...
The production of fourth-generation quarks at the Superconducting Super Collider is studied concentrating on event signatures resulting from the single-lepton and two-lepton decay modes. We find that events with multijets (njet≥3) and one or two high-pT leptons are good signals for heavy-quark production for quark masses up to 600 GeV. In addition, we also found that the total transverse energy of an event is useful for distinguishing between heavy-quark production and the top-quark background.
The decay of V50 has been studied with a low-background, three-crystal intrinsic Ge detector operating in a salt mine. The partial half-life for electron-capture decay to the first excited state of Ti50 has been estim...
The decay of V50 has been studied with a low-background, three-crystal intrinsic Ge detector operating in a salt mine. The partial half-life for electron-capture decay to the first excited state of Ti50 has been estimated to be (2.05±0.49)×1017 yr, and the partial half-life for β− decay to the first excited state of Cr50 has been estimated to be (8.2−3.1+13.1)×1017 yr.
A measurement of the β spectrum of tritium implanted into a hyperpure germanium detector is reported. A distortion is observed 17 keV below the end point which is in agreement with an earlier measurement involving a ...
A measurement of the β spectrum of tritium implanted into a hyperpure germanium detector is reported. A distortion is observed 17 keV below the end point which is in agreement with an earlier measurement involving a tritium-implanted Si(Li) detector. The excess of counts observed in the low-energy region of the tritium spectrum is best described by the emission of a 16.9±0.1 keV neutrino and a mixing probability between 0.6 and 1.6% when allowance is made for uncertainty in the effective screening potential appropriate for tritium bound within a crystal lattice.
Two measurements of the β spectrum of S35 have been made using a windowless Si(Li) detector. The data show a clear threshold anomaly at Q-17 keV which is consistent with the emission of a 16.9±0.4 keV neutrino w...
Two measurements of the β spectrum of S35 have been made using a windowless Si(Li) detector. The data show a clear threshold anomaly at Q-17 keV which is consistent with the emission of a 16.9±0.4 keV neutrino with a mixing probability of (0.73±0.09±0.06)%. All values of mixing probability <0.26% are rejected at the 99% confidence level.
A generalization of the McMillan-Kobayashi mean-field theory of smectic-A liquid crystals to explicitly include anisotropic hard-core interactions is described. Hard-core effects are incorporated using perturbation ar...
A generalization of the McMillan-Kobayashi mean-field theory of smectic-A liquid crystals to explicitly include anisotropic hard-core interactions is described. Hard-core effects are incorporated using perturbation arguments on a reference system of aligned parallel ellipsoids with effective shape parameters, which is treated by a nonlocal-density-functional approach. The results reveal the necessity of including both anisotropic repulsions and certain ‘‘symmetry-breaking’’ attractive interactions, usually omitted from McMillan-Kobayashi treatments, for obtaining stable smectic-A phases. The theory shows explicitly how the interlayer distance in a smectic phase results, variationally, from incompressibility of the hard cores. Phase diagrams that include nematic, smectic, as well as isotropic liquid and vapor phases are presented, using both temperature and density (or pressure) as independent variables.
Quark-pair transmutation via two gluons is the lowest-order, color-singlet process. In this paper the helicity amplitudes for this process are evaluated and a partial-wave analysis performed. The amplitudes for these ...
Quark-pair transmutation via two gluons is the lowest-order, color-singlet process. In this paper the helicity amplitudes for this process are evaluated and a partial-wave analysis performed. The amplitudes for these annihilations are infrared divergent and this divergence is removed by giving the gluons a confinement mass. The results are generally dependent on this mass. Many of the features are similar to those of quark-pair annihilation into two gluons. Somewhat surprisingly, there is a large proportion of a 1+ partial wave. Threshold effects are understood in terms of threshold effects in pair annihilation into two gluons. However, there is a ‘‘competition’’ effect that depends on the ratio of masses of the initial- and final-quark pairs. For similar masses, singlet production dominates as expected, but for very dissimilar masses, singlet annihilation of the heavier pair competes with triplet production of the lighter pair. Some comments about the possible applications and extensions of this work are made. Obvious applications are to the Okubo-Zweig-Iizuka-rule-suppressed decays of quarkonia. Other applications include development of a quark-pair-creation model that differs from the usual P03 and S13 models.
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