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991.
In composite models of quarks, leptons and weak bosons whereW-constituents are colored objects, color octet partners ofW ± andZ 0 are predicted. We study in detail the phenomenology of these particles. Independent of the specific model one expects a color octet isotriplet of vector bosons (W 8 ± ,Z 8 0 ) with mass in the range of 100–200 GeV, and a color octet isosinglet vector bosonV 8 0 with substantially larger mass, due to mixing with the gluon. Moreover, relatively light color octet excitations of the leptons appear, while the existence of “color exotic” partners of the quarks is model dependent. These particles decay mainly into a lepton (quark) and a gluon. We construct the couplings ofW 8 ± ,Z 8 0 andV 8 0 to ordinary and “color exotic” fermions. The signals of color octet weak bosons in low energy weak reactions are explored in detail. The production cross section ofW 8 ± (Z 8 0 ) in hadron-hadron collisions is calculated for \(0.54TeV \leqq \sqrt s \leqq 20TeV\) . Various decay modes of colored weak bosons are studied. The most prominent decay signatures ofW 8 ± andZ 8 0 are events of the type (l +-: charged lepton;j: hadronic jet; : missing transverse momentum). The present CERN \(p\bar p\) collider data on such events are discussed in the light ofW 8 ± andZ 8 0 decays. If colored weak bosons are not found with a mass less than ~250 GeV composite model building will be strongly restricted. 相似文献
992.
N. Freyer M. Kiskinova G. Pirug H. P. Bonzel 《Applied Physics A: Materials Science & Processing》1986,39(3):209-219
The adsorption of CO and NO on the (1×2) and (1×1) modifications of the Pt(110) surface was studied by x-ray photoemission spectroscopy, LEED and work-function change measurements. The O(1s) binding energy of adsorbed CO is site-specific and differentiates between on-top and bridge adsorbed species. CO adsorption on Pt(110)(1×2) at 120 K occurred sequentially into on-top and bridge sites yielding an orderedc(8×4) layer at the maximum coverage. At 300 K only on-top bonded CO was present after CO adsorption on the (1×2) surface. CO adsorption on the (1×1) surface at 120 K showed a transient bridge adsorbed CO and on-top CO at saturation, with an ordered (2×1)p1g1 LEED pattern. Heating the (2×1)p1g1 CO layer to 400 K also showed this transient bridge CO species. Work function changes generally correlated with the appearance of different CO species but were complex in detail. The findings for CO adsorption are consistent with the missing row model of the (1×2) surface.Parallel data for NO adsorption on (1×2) and (1×1) surfaces at 120 K were less informative than those for CO because O(1s) spectra showed single broad peaks. Peak contributions due to bridge and on-top bonded NO could be estimated. 相似文献
993.
Low temperature Mössbauer spectra and magnetic ordering of lithiated ferric molybdate: Li2Fe2(MoO4)3
Powder x-ray diffraction, variable temperature magnetic susceptibility, and zero field Mössbauer spectroscopy measurements were used to characterize the new phase Li2Fe2 (MoO4)3. This material is obtained topochemically simply by the mixing of solutions of lithium iodide in acetonitrile with solid Fe2(MoO4)3 at ambient temperature. Li2Fe2(MoO4)3 possesses the high temperature orthorhombic ferric molybdate $$\begin{gathered} Fe_2 (MoO_4 )_3 + 2LiI\xrightarrow{{CH_3 CN}}Li_2 Fe_2 (MoO_4 )_3 + I_2 \hfill \\ (solid)(solution)(solid)(solution) \hfill \\ \end{gathered}$$ structure. Guinier photographs were completely indexed in space group Pnca. Magnetic hyperfine splitting of the zero field Mössbauer spectrum below 12.5 K indicates a three-dimensional magnetically ordered state which susceptibility results show to be weakly ferromagnetic owing to probable canting of antiferromagnetically coupled sublattices. 相似文献
994.
H. Mahdjour C. Pappa R. Wendler K. Baberschke 《Zeitschrift für Physik B Condensed Matter》1986,63(3):351-364
The ESR of the spin glassAgMn (2.7 and 9.6 at %) has been investigated below and aboveT
g(0.1T
g<T<5T
g) at various microwave frequencies. The analysis yields:1) No explicit frequency dependence but strong magnetic field effects, inherent with ESR-experiments.2) Part of the excess line width is identified as critical spin fluctuations, following a power law. However, because of the presence of the applied field, the reduced temperaturet is not a good scaling variable. We choose the non-linear susceptibility X
s
divided byH
2, which scales as the order parameter susceptibility. The experiment yieldsW
ex(X
s
/H
2)
p
,p=0.42. From this we deduce z3. 相似文献
995.
G. R. Sudhakaran R. L. Bhattacharjee J. C. Sarker L. H. Johnston 《International Journal of Infrared and Millimeter Waves》1986,7(12):1903-1911
A submillimeter laser Stark spectrum has been observed for fully deuterated Methyl Chloride (CD3Cl) with the 337 m line of the HCN laser up to Stark fields of about 54000 V/cm. The spectra were taken for both Parallel and Perpendicular Polarizations and the multiplet transitions were identified as JK=42K41K in the ground vibrational state. Three families with K=12, 13 and 14 have been identified and their zero field frequencies have been given with improved accuracy over those calculated from available molecular constants. 相似文献
996.
G. Lhersonneau D. Weiler P. Kohl H. Ohm K. Sistemich R. A. Meyer 《Zeitschrift für Physik A Hadrons and Nuclei》1986,323(1):59-67
An isomeric state at 3,523 keV excitation energy in97Y with a half-life of 144(10) ms has been discovered with the fission-product separator JOSEF. This isomer is depopulated through aγ transition of 162 keV. AnE3 multipolarity for this transition is consistent with the measured conversion coefficients ofα K =0.98(20) andα T =1.00(19). Subsequent electromagnetic transitions populate several new97Y levels which have high spins. For the isomer the three-quasiparticle configuration [πg 9/2?ν(h 11/2,g 7/2)]27/2? is proposed. TheE3 transition with a strength about 2 single-particle units is supposed to be of the typeh 11 2/+1 →d 5 2/?1 . These findings provide evidence for the rapid shape transition atA?100 since they indicate shell-model character of 39 97 Y58 even at high excitation energies while the immediate neighbour 39 98 Y59 contains a rotational band based on a level at 495 keV. 相似文献
997.
H. -O. Carmesin D. W. Heermann K. Binder 《Zeitschrift für Physik B Condensed Matter》1986,65(1):89-102
Instead of the standard assumption in the theory of phase separation where an instantaneous quench from an initial equilibrium state to the final state in the two-phase region is assumed, we consider the more realistic situation that the change of the external control parameter (e.g. temperature) can only be performed with finite rates. During the initial stages of spinodal decomposition the system then has some memory of the states intermediate between the initial and the final one. This influence of the finite quench rate in continuous quenching procedures is studied within the linearized theory of spinodal decomposition, with the Langer-Baron-Miller decoupling, and with Monte Carlo simulations. Both the case of thermally activated mobilities (applicable to solid metallic alloys) and the case of nearly temperature-independent mobilities (applicable to fluid polymer mixtures) are treated, and possible experimental applications are discussed. We find drastic deviations from the standard instantaneous quench situations in all cases of experimental interest. 相似文献
998.
The detailed temperature variation of the Mössbauer spectral intensity in Sn(CH3)4 displays a pronounced drop of the Debye temperature from
D
96K below the transition temperature (T
t
43K) to
D
76K above it. The transition atT
t
is discussed in terms of recent INS and NMR results where increased motion of inequivalent CH3 groups has been observed around the temperatureT
t
.Supported by the U.S.-Israel Binational Science Foundation 相似文献
999.
1000.
Dr. H. Demel Dipl.-Ing H. J. Grießer Prof. Dr. K. Hummel 《Colloid and polymer science》1977,255(11):1131-1132
Ohne ZusammenfassungMit 1 Abbildung und 1 Tabelle 相似文献