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1.
Gyan Mohan 《Pramana》1983,21(3):201-206
That the longlived componentL ofK
0 has bothcp=+1 andcp=−1 modes of decay is often cited as evidence of violation ofcp invariance. The careful ones find the compelling evidence to be the non-dilution of the regeneration interference pattern
when the incidentK
0 beam is mixed even substantially with
. However the two phenomena comprehensively imply thatL has acp=+1 componentL
+ and acp=−1 componentL
− and that the longlived component of bothK
0 and
are one and the sameL. This does not demand abandoningcp invariance. It does imply that
is not thecp conjugate ofK
0. 相似文献
2.
The electrical and photoelectrical properties of plasma polymerized acrylonitrile (PAN) are reported. The polymer films were studied in silver-PAN-silver systems. Electrical conductivity at room temperature was of the order of 10−11 ohm−1 cm−1. The space charge limited current (SCLC) studies at room temperature and thermally stimulated current studies (TSC) over a temperature range of 290–500°K led to a clear understanding of carrier concentration, carrier mobility, trapping
levels and activation energies. Photoelectric measurements were used to draw a band picture in plasma depositedPAN. 相似文献
3.
The pressure dependence of thelo-to phonons in InAs has been investigated by Raman scattering using the diamond anvil cell. Indium arsenide transforms, presumably
to the rock-salt structure at 70±1 kbar. The mode Grüneisen parameters for thelo-to phonons are γ
lo
=0.99±0.03, γ
to
=1.2±0.03 respectively. The effective charge,e*
T
, for InAs decreases slightly with pressure and this trend is in accordance with the behaviour of other III–V zinc blende
structured semiconductors: The structural phase transition is discussed in the light of theoretical calculations for phase
stability of III–V compounds, as well as recent high pressure x-ray diffraction studies. 相似文献
4.
The extended x-ray absorption fine structure (EXAFS) associated with the GeK x-ray absorption discontinuity in pure germanium and in the intermetallics RGe2 (R=La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er and Y) has been studied. The Ge-R distances in these compounds have been determined
by comparing the experimental phase shifts with the theoretical ones. The Ge-R distances in the compounds TbGe2, HoGe2 and ErGe2 are being reported for the first time in this work. 相似文献
5.
C. Thierfelder P. Schwerdtfeger F. P. Heßberger S. Hofmann 《The European Physical Journal A - Hadrons and Nuclei》2008,36(2):227-231
The K -shell and L -shell ionizations potentials for 268
109Mt were calculated at the Dirac-Hartree-Fock level taking into account quantum electrodynamic and finite nuclear-size effects.
The K
α1 transition energies for different ionization states are accurately predicted and compared with recent experiments in the
α -decay of 272
111Rg . 相似文献
6.
To explore the Coriolis attenuation problem we have carried out a schematici
13/2 rotor plus single quasi-particle band-mixing calculation. The results reveal that the calculations are largely insensitive
towards the location of the Fermi energy near the low-K single particle states only, and therefore are incapable of taking into account the transition from ‘full’ decoupling to
‘partial’ decoupling as the Fermi level is increased. We trace the possible reasons for this insensitivity and find that this
may be primarily due to thebcs approximation for calculating the quasiparticle energies. 相似文献
7.
P C Vaidya 《Pramana》1985,25(5):513-518
A metric containing a parameterb is presented. It represents two distinct families of space-times, the Taub-nut family and the deSitter family, according asb=1 andb=4 respectively.
The metric of the deSitter family of space-times contains a further parameterm. Whenm=0, the space-time is the usual homogeneous and isotropic deSitter space-time. But ifm≠0, the metric represents a space-time which is homogeneous but not isotropic satisfyingR
ik
=Λg
ik
. In this space-time, the 4-velocity of an observer at rest will have non-zero twist. The metric withb=4,m≠0 is interpreted as a metric representing a “rotating deSitter space-time”. 相似文献
8.
In an effort to resolve the existing discrepancy between experiment and theory, the cross-sections for the production ofL
l,L
α
,L
β
andL
γ
groups ofL-shell X-rays of Ho by photons of nine energies in the range 10–40 keV have been measured using an improved version of annular
source double reflection geometrical set-up. Contrary to the earlier findings of Garget al that the measured values of the cross-sections are consistently higher than those calculated theoretically, the present results
do not confirm this. The plausible deficiencies in the experiments of Garget al are pointed out and possible remedies to overcome them are suggested. It is concluded that the higher values obtained by
Garget al are probably due to systematic errors in their method of measurement. 相似文献
9.
The Raman spectra of the single crystal of K2Zn(SO4)2·6H2O belonging toC
2h
5
space group in the 40–1200 cm−1 region in different scattering geometries and their spectra ofthe microcrystalline salt in the 1500-50 cm−1 region have been reported. The dynamics of the crystal has been described in terms of 186 phonon modes under the unit cell
approximation. The weak bands in the region 400–900 cm−1 have been assigned to the libratory modes of H2O molecules in contradiction to the assignments reported by Ananthanarayanan. The ambiguities existing in the literature about
the assignments ofν
2
c
andν
5
c
modes of [Zn(H2O)6]2+ have also been removed. The translatory and libratory modes of different units of the crystal have been identified and assignments
are made using farir and Raman data on various isomorphous tutton salts.
It has been inferred that both SO
4
2−
tetrahedron and [Zn(H2O)6]2+ octahedron undergo linear as well as angular distortions from their free state symmetries in the crystal. 相似文献
10.
The yield and energy distribution of long-range alpha-particles (lra) emitted from neutron-induced fission of235U have been measured at neutron energies; thermal, 125±12, 155±11, 185±10, 210±9, 240±9, 365±50 and 480±45 keV. The long-range
alpha-particles were detected in cellulose nitrate track detector foils. Results showed an increase of about 50% in the yield
at neutron energies in the region 150 keV≤E
n≤220 keV as compared to that of thermal neutrons. A calculation has been carried out to extract thelra to binary fission ratio forp-wave neutron induced fission. 相似文献
11.
We give here a review of the recent developments of grand unified theories based onN=1 supergravity. We start with a brief introduction of supersymmetry and supergravity multiplets, and then discuss the construction
of an invariant Lagrangian. The phenomena of gravity-induced weak symmetry breaking via the super Higgs effect at the tree
level, corresponding to the conventional SU(5) gauge group, are then considered. We then extend this idea to the larger group
SO(10), showing two possible breaking chains given as (i) SO(10)×susy→SU(2)
L
×U(1)
R
×U(1)
B-L
×SU(3)
C
(≡ G2113)×susy→U(1)em×SU(3)
C
(G
LE
) predicting a secondZ-boson having mass lower than 1 TeV, and (ii) SO(10)×susy→SU(2)
L
×SU(2)
R
×SU(4)→(≡G224)×susy→ SU(2)
L
×U(1)
Y
×SU(3)
C
(≡ G213)×susy→U(1)em×SU(3)
C
. We also consider the radiative breaking of weak symmetry via renormalisation group effects, which predicts the top quark
mass. Some experimental signatures of the supersymmetric particles are investigated and possible future outlook is discussed.
Invited talk presented at the International Symposium on Theoretical Physics, Bangalore, November 1984. 相似文献
12.
We investigate the asymmetries arising due to electromagnetic interactions in largeP
T pion inclusive processes. The hardqcd processes that contribute to such asymmetries areq+g→q+γ,q+q→g+γ etc. which are suspected to be substantial, as indicated by theqcd predictions for a significant and increasingγ/π
o ratio at largeP
T. We calculate the expected isospin related asymmetries and propose tests that might detect them. Our estimates indicate that
the effects are much smaller than may be naively expected. We also observe a remarkable scaling of asymmetries in the variableP
T/(s)1/2. 相似文献
13.
S. Rai Choudhury A. S. Cornell Naveen Gaur 《The European Physical Journal C - Particles and Fields》2008,58(2):251-259
Flavor changing neutral current (FCNC) decays of the B-meson are a very useful tool for studying possible physics scenarios beyond the standard model (SM), where of the many FCNC
modes radiative, purely leptonic and semi-leptonic decays of the B-meson are relatively clean tests. Within this context, the BELLE collaboration has measured the process B→K
*
γ and also searched for the B→K
1(1270)γ process. Theoretical analyses of these processes are yielding similar values of the relevant form factors. In this work we
have used this upper bound in studying the angular correlations for the related semi-leptonic decay mode B
−→K
1−(1270)(→ρ
0
K
−)ℓ
+
ℓ
−, where we have used the form factors that have already been estimated for the B→K
1(1270)γ mode. Note that the additional form factors that are required were calculated using large energy effective theory (LEET). 相似文献
14.
It has recently been shown that any physical quantity ℛ, in perturbation theory, can be obtained as a function of only the
renormalization scheme (rs) invariants,ρ
0,ρ
1,ρ
2, … Physical predictions, to any given order, are renormalization scheme independent in this approach. Quantum chromodynamics
(qcd) predictions to second order, within thisrs-invariant perturbation theory, are given here for several processes. These lead to some novel relations between experimentally
measurable quantities, which do not involve the unknownqcd scale parameter Λ. They can therefore be directly confronted with experiments and this has been done wherever possible. It
is suggested that these relations can be used to probe the neglected higher order corrections. 相似文献
15.
A study of theEXAFS associated with theK x-ray absorption discontinuity of germanium in pure germanium and in the rare-earth germanides RGe2 (where R=La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er and Y) has been carried out. The Ge-Ge distances have been obtained in these
compounds. Considering the phase to the RGe2 system, the bond lengths in these compounds have been determined. The values obtained by us for the RGe2 compounds (R=La, Ce, Pr, Nd, Sm, Gd, Dy and Y) agree with those obtained earlier by crystallographic methods. The bond lengths
for the compounds TbGe2, HoGe2 and ErGe2 are also being reported. 相似文献
16.
C P D Dwivedi 《Pramana》1984,23(4):529-539
The geometry, bond order, binding energy, ionisation potential, dipole moment and net charges have been calculated for cis-N2O2, trans-N2O2, N2O4, BF3, CH3, NH3, BH3 and B2H6 systems using semiempirical molecular orbital methodsindo and the results compared with available experimental,ab initio andmindo/3 data. 相似文献
17.
Summary Capacitance-voltage measurements have been carried out onp-type ɛ-GaSe single crystal ∥c in the temperature range 300 to 360 K, with applied voltages of -1, 0 and +1 V. TheC-V measurements in this temperature range have shown a shift in capacitanceC and conductanceG to the higher values with an increase in temperature. The depletion layer widthW, the Debye length LD and the doping densityN
α
have been worked out and plots ofN
α
vs. W have shown a decrease inW with an increase in temperature. The plots of LD
vs. N
α
vary as 1/Nα1/2, which gives NαLD ⋍ 3.3 × 1011 charges/m2 for doping density of 1016m−3. The values ofG at different temperatures have been used to obtain the activation energies, which are found to be ΔE ⋍ 0.11 eV for -1 and
+1 V applied voltages, and ΔE ⋍ 0.06 eV for zero volt.
The authors of this paper have agreed to not receive the proofs for correction. 相似文献
18.
For the potentialV(x)=V
0 tan2
x, the corrections to the lowest orderjwkb (Bohr-Sommerfeld) energy quantization rule are non-zero. These higher order corrections are explicitly computed using the
formalism of Dunham. The resultingjwkb series for the energy eigenvalues is summable, and yields the exact bound state spectrum. 相似文献
19.
1H spin-lattice relaxation rate (T
1
−1
) has been measured using inversion recovery technique in polycrystalline (NH4)2SbF5 system in the temperature range 140–400 K. From the plot of log (M
0−M) againstτ, we have estimated two differentT
1 corresponding to two inequivalent ammonium ions in the unit cell. Temperature-dependence ofT
1 in each case exhibits features of double minima indicating the influence of different correlation times corresponding to
different types of motion. Activation energies at different temperature regions have been estimated. Some features of dynamics
of motion of the different groups of ions across the phase transitions have been discussed. 相似文献
20.
Y K Agarwal C V K Baba D Bhattacharya S K Bhattacherjee R K Bhowmik V M Datar H C Jain A Roy 《Pramana》1987,29(6):559-575
In-beam nuclear spectroscopic studies of182Re, following the reaction181Ta(α, 3n)182Re have been made using gamma-ray and internal conversion electron techniques.K-conversion coefficients for several transitions have been measured and the multi-polarities of the various transitions assigned.
In particular, the spin and parity of the four-quasi-particle isomeric level at 2256 keV were determined to be 16−. Theg-factor of this level has been measured to beg = 0·32 ± 0·05. On the basis of theg-factor and the decay pattern of this level, a configuration {v9/2+ [624↑]v7/2− [514↓]v7/2− [503↑]π9/2− [514↑]}
k
x = 16− has been assigned to this level. The nature of the retardation of the gamma transitions deexciting this level is discussed.
It is argued that the measured retardation factors can be explained if the nucleus has a triaxial shape. 相似文献