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1.
We analyse all the neutral-current phenomena following from the general class of gauge models based on the group SU(2)
L
⊗ SU(2)
R
⊗ U(1). It is found that the neutral-current couplings in these models bear a remarkable similarity to those in the standard
Weinberg-Salam gauge model. The parameter which plays the role of sin2ϑw is found to lie between 0 and 1/2. Comparison with experimental data shows that even a model with the ratio of the masses
of the twoZ bosons as small as 1.9 is not ruled out. 相似文献
2.
We present a detailed analysis of the nonperturbativeβ function along the Wilson axis for theSU(3) pure gauge theory using the Monte Carlo renormalization group method. The scaling behavior of the string tension, the
deconfinement transition temperature, and the O++ glueball mass obtained from published data is compared. The results show that there is no asymptotic scaling forK
F=(6/g
2)<6.1. We also estimate the renormalized action generated by the √3 block transformation for use in future calculations. 相似文献
3.
The anomalous magnetic moment of muon is calculated in anSU(3)×U(1) gauge model proposed by Gupta and Mani. We find the contribution due to the intermediate gauge bosons to be of the same
order of magnitude as in Weinberg. Salam model. The deep-inelastic structure functions are also analysed in the same model
and inequalities for the structure functions are obtained in the light-cone algebra approach. 相似文献
4.
R Ramachandran 《Pramana》1979,12(3):227-234
Treating the breaking of colour symmetry via the mixing between the colour gluons and weak bosons (a la Rajasekaran and Roy)
it is observed that the colour contribution to the effective weak vertex of a quark at zero momentum transfer is zero uptoO(α).
An erratum to this article is available at . 相似文献
5.
Painlevé test for integrability for the combined equations generated from Yang’s self-dual equations for SU (2) gauge fields and Charap’s equations for chiral invariant model of pion dynamics faces some peculiar situations that allow
none of the stages (leading order analysis, resonance calculation and checking of the existence of the requisite number of
arbitrary functions) to be conclusive. It is also revealed from a comparative study with the previous results that the existence
of abnormal behaviour at any of the stated stages may have a correlation with the existence of chaotic property or some other
properties that do not correspond to solitonic behaviour.
相似文献
6.
V. K. B. Kota 《Pramana》2003,60(1):59-74
It is shown that the proton-neutron interacting boson model (pnIBM) admits new symmetry limits withO(12) algebra which breakF spin but preserves theF
z quantum numberM
F. The generators ofO(12) are derived and the quantum numberU ofO(12) for a given boson numberN is determined by identifying the corresponding quasi-spin algebra. TheO(12) algebra generates two symmetry schemes and for both of them, complete classification of the basis states and typical
spectra are given. With theO(12) algebra identified, complete classification of pnIBM symmetry limits with goodM
F is established. 相似文献
7.
The recently discovered narrow peaks (theψ-particles) in e+e− system at 3.105 and 3.695 GeV are interpreted as hadrons in a broken SU4 symmetry scheme. A new additional additive quantum number, parachargeZ, is combined with the usual SU3 quantum numbers in the group SU4. Theψ (3.1) is assigned to a near ideally mixed15⊕1 multiplet of vector mesons (containing theρ) as theI=Y=0, charge conjugationC=−combination ofZ=±1.members. Theψ (3.7) is assigned correspondingly to another mixed15⊕1 multiplet containing theρ′ (1600). The hadronic electromagnetic interactions are modified by the addition of (non-minimal) anomalous pieces that can
changeZ. The decays of theψ-particles are discussed. New enlarged SU4 multiplets of other hadrons are proposed. Tests of our scheme are put forward. The most crucial test will be the observation
of two rather broad resonances in e+ e− collisions with masses around 4.2 GeV and 5.1 GeV. Another prediction is the presence of energetic photons in the decays
of theψ-particles. Important results concerning the recently observed phenomena in the process e+e−→hadrons follow in this scheme. 相似文献
8.
YbCu5−x
Al
x
provides the possibility to tune ground state properties by a change of the valence due to the Cu/Al substitution, by pressure
as well as by the application of a magnetic field. Near to the critical concentration x
cr≈1.5 non-Fermi-liquid properties (NFL) are obvious, obeying hyperscaling. If magnetic order sets in for x>1.5, the application of moderate magnetic fields quenches order and again NFL features become evident. Hyperscaling in this
case indicates strongly interacting spin fluctuations. 相似文献
9.
Homogeneous (LiCl)
x
(P2O5)1 − x
glasses were synthesised using a melt-quenching method for x = 0.1–0.6 in the interval of 0.05. The amorphous structure of the samples was evident by the X-ray diffraction spectrum.
The short range structures of the binary phosphate samples were examined by Fourier transform infrared spectroscopy, whilst
the density of the samples was measured as supportive data for the investigations. The results of refractive indices as measured
using an ellipsometer reveal the homogeneity of samples and was found to depend on the glass composition. The electrical properties
of the glasses were investigated by ac impedance spectroscopy from 10 mHz to 1 MHz for temperatures ranging from room temperature
to 573 K. An estimation of the bulk resistivity was obtained by taking the intercepts on the real axis at low frequencies
of the complex impedance plot. The dc conductivities derived from the reciprocal of resistivity values were found to obey
the Arrhenius relationship, and its activation energy shows a decreasing trend with the increase in LiCl content in the glass.
Lastly, an equivalent circuits consisting of real and complex capacitors is proposed to describe the dielectric response of
the glass. 相似文献
10.
Painlevé test (Jimboet al [1]) for integrability for the Yang’s self-dual equations forSU(2) gauge fields has been revisited. Jimboet al analysed the complex form of the equations with a rather restricted form of singularity manifold. They did not discuss exact
solutions in that context. Here the analysis has been done starting from the real form of the same equations and keeping the
singularity manifold completely general in nature. It has been found that the equations, in real form, pass the Painlevé test
for integrability. The truncation procedure of the same analysis leads to non-trivial exact solutions obtained previously
and auto-Backlund transformation between two pairs of those solutions 相似文献
11.
Variation-after-projection (VAP) calculations in conjunction with Hartree-Bogoliubov (HB) ansatz have been carried out for
A=100−108 molybdenum (Mo) isotopes. In this framework, the yrast spectra with J
max
π
≥10+, B(E2) transition probabilities, quadrupole (β2) and hexadecapole (β4) deformation parameters, moment of inertia (I) and square of cranking frequency (ω2) for even-even Mo isotopes have been obtained. The results of the calculation give an indication that it is important to
include the hexadecapole-hexadecapole component of the two-body interaction for obtaining various nuclear structure quantities
in these Mo isotopes. 相似文献
12.
C. Estournès C. D’Orléans J.-L. Rehspringer E. Manova B. Kunev D. Paneva I. Mitov L. Petrov M. Kurmoo 《Hyperfine Interactions》2005,165(1-4):61-67
Magnetic nanoparticles of cobalt ferrites Co
x
Fe3−x
O4 (x = 1 or 2) have been obtained either by mechanical milling or thermal treatment of pre-prepared layered double hydroxide carbonate
x-LDH–CO3. Mechanical milling of the 1-LDH–CO3 leads to the large-scale preparation of nearly spherical nanoparticles of CoFe2O4, the size of which (5 to 20 nm) is controlled by the treatment time. Core-shell structure with surface spin-canting has been
considered for the nanoparticles formed to explain the observed hysteresis loop shift (from ZFC–FC) in the magnetic properties.
Annealing treatment of the 2-LDH–CO3 below 673 K results in the formation of nearly spherical pure Co2FeO4 nanoparticles. At 673 K and above, the LDH decomposition leads to the formation of a mixture of both spinels phases Co2FeO4 and CoFe2O4, the amount of the latter increases with annealing temperature. Unusually high magnetic hardness characterized by a 22 kOe
coercive field at 1.8 K has been observed, which reflects the high intrinsic anisotropy for Co2FeO4. 相似文献
13.
Recep Eryi?it 《International Journal of Theoretical Physics》2009,48(3):885-893
We have analyzed the behavior of multipartite global entanglement and average bipartite concurrence for the sign of quantum
phase transitions in the frustrated J
1−J
2 model by using exact diagonalization technique for a chain of 12 qubits. It is found that although the magnitude of two classes
of the measures show opposite trends the absolute value of their derivatives show similar structure near critical points. 相似文献
14.
TheU
B(6)⊗U
F(20) Bose-Fermi dynamical symmetry of interacting boson-fermion model arises when the odd nucleon occupies single particle
orbits withj=1/2, 3/2, 5/2, and 7/2. The subgroup structures ofU
B(6)⊗U
F(20) related to theU
B(5) andO
B(6) limits of sdIBM (U
B(6)) are analysed. Broadly speaking,U
B(6)⊗U
F(20) admitsU
BF(5)⊗U
s
F
(4), SpinBF(5)⊗U
k
F
(5) andU
BF(5)⊗U
s
F
(2) limits withU
B(5) core and SpinBF(6),O
BF(5)⊗U
s
F
(4), SpinBF(6)⊗U
k
F
(5) andO
BF(6)⊗U
s
F
(2) limits withO
B(6) core respectively. For each of these seven symmetry limits, group chains, quantum numbers labelling the basis states,
generators and Casimir operators for the various subgroups and energy formulas are given. Recoupling coefficients (reduced
Wigner coefficients) for constructing wavefunctions of low-lying states are tabulated and these will allow (together with
sdIBMU
B(5) andO
B(6) limit results) one to calculateB(E2)’s,B(M1)’s, one and two nucleon transfer strengths etc. in the seven symmetry limits. Experimental examples for theU
B(6)⊗U
F(20) symmetry limits are briefly discussed. 相似文献
15.
The structures and hydrogen storage properties of sodium atoms decorated B6 clusters are investigated by the B3LYP method with a 6-311+G (d, p) basis set. For NamB6 (m = 1-3) clusters, Na atoms are always inclined to separate far enough from each other and not cluster together on a B6 cluster surface so that each Na atom has sufficient space to bind hydrogen molecules. The hydrogen storage gravimetric density of a two Na atoms decorated B6 cluster is 17.91 wt% with an adsorption energy per H2 molecule (AAE/H2) of 0.6851 kcal.mo1^-1. The appropriate AAE/H2 and preferable gravimetric density of the two Na atoms decorated B6 cluster complex indicate that it is feasible for hydrogen storage application in ambient conditions. 相似文献
16.
Cross-sections for production of evaporation residues from the compound nucleus96Ru* formed by fusion reactions28Si+68Zn,32S+64Ni,37Cl+59Co and45Sc+51V have been obtained from the yields of their characteristicγ-rays. The measurements span an excitation energy range of 55 MeV to 70 MeV of the compound nucleus. The evaporation residue
(ER) cross-sections have been analysed in terms of statistical model for the decay of the compound nucleus. A good agreement
is found between statistical model calculation and the experimental evaporation residue cross-sections in all the four cases.
It is shown that the average angular momentum
of the compound nucleus can be deduced from a comparison of the experimentally measured and the statistical model predictions
for the ER cross-sections. The validity of this method of deriving
has been discussed for the case of16O+154Sm system. 相似文献
17.
Sujoy Poddar 《Pramana》2007,69(5):839-842
In a R-parity violating (RPV) model of neutrino mass with three bilinear couplings μ
i
and three trilinear couplings λ′
i33, where i is the lepton index, we find six generic scenarios each with a distinctive pattern of the trilinear couplings consistent
with the neutrino oscillation data. These patterns may be reflected in direct RPV decays of the lighter top squark or in the
RPV decays of the lightest superparticle, assumed to be the lightest neutralino. Typical signal sizes at the Tevatron RUN
II and the LHC have been estimated and the results turn out to be encouraging.
相似文献
18.
Two kinds of general consequences of the ΔS=0 weak hadron neutral current independent of a gauge model are presented. Firstly are results which depend on the quark parton
model. These involve bounds among neutrino inclusive cross-section and a bound onQ(Z, N) in terms of these inclusive cross-sections. Secondly are results which are independent of the quark-parton model and depend
only on the SU(3) structure of the most general ΔS=0 neutral current. These tests of isopin and speciallyU-spin properties of the current are given forv+N→v+hadron+anything,v+N→v+baryon+meson ande
+
e
−→baryon+anti-baryon. In addition some conjectures are made with regard to the semi-inclusive neutrino-reactions using the
quark parton model. 相似文献
19.
Y. Funaki A. Tohsaki H. Horiuchi P. Schuck G. Röpke 《The European Physical Journal A - Hadrons and Nuclei》2006,28(3):259-263
In order to discuss the spatial extention of the 02
+-state of 12C (Hoyle state), we analyze the inelastic form factor of electron scattering to the Hoyle state, which our 3α-condensate wave
function reproduces very well like previous 3α RGM/GCM models. The analysis is made by varying the size of the Hoyle state
artificially. As a result, we find that only the maximum value of the form factor sensitively depends on its size, while the
positions of maximum and minimum are almost unchanged. This size dependence is found to come from a characteristic feature
of the transition density from the ground state to the Hoyle state. We further show the theoretical predictions of the inelastic
form factor to the 22
+-state of 12C, which was recently observed above the Hoyle state, and of the inelastic form factor to the calculated 03
+-state of 16O, which was conjectured to correspond to the 4α condensed state in previous theoretical work by the present authors. 相似文献
20.
V. V. Parkar V. Jha S. Santra B. J. Roy K. Ramachandran A. Shrivastava K. Mahata A. Chatterjee S. Kailas 《Pramana》2009,72(2):363-373
The elastic scattering and the 6He angular distributions were measured in 7Li + 7Li reaction at two energies, E
lab = 20 and 25 MeV. FRDWBA calculations have been performed to explain the measured 6He data. The calculations were very sensitive to the choice of the optical model potentials in entrance and exit channels.
The one-step proton transfer was found to be the dominant reaction mechanism in 6He production.
相似文献