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1.
At electron densities N
S>6×10−2 cm−22 a second series of oscillations, which are tentatively attributed to population of the second energy subband, is observed
in addition to the main series of Shubnikov-de Haas oscillations. A change in phase of the oscillations of the second series
is observed at some angle of inclination αe of the field. The measured value of αe is used to calculate the ratio of the cyclotron mass to the effective g factor. The maximum possible cyclotron mass is also determined as m
H< 0.32m
e. On this basis it is concluded that the second series of oscillations is due to electrons which have an in-plane effective
mass m*≈0.2m
e and which belong to the same valleys of the Fermi surface as in the case of the main oscillations.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 2, 136–140 (25 January 1998) 相似文献
2.
D. N. Voskresensky E. E. Kolomeitsev B. Kämpfer 《Journal of Experimental and Theoretical Physics》1998,87(2):211-217
We consider massive photon decay reactions via intermediate states of electron-electron-holes and proton-proton-holes into
neutrino-antineutrino pairs in the course of neutron star cooling. These reactions may become operative in hot neutron stars
in the region of proton pairing where the photon due to the Higgs-Meissner effect acquires an effective mass m
γ
that is small compared to the corresponding plasma frequency. The contribution of these reactions to neutrino emissivity
is calculated; it varies with the temperature and the photon mass as T
3/2
m
γ
7/2
exp(−m
γ
/T) for T<m
γ
. Estimates show that these processes appear as extra efficient cooling channels of neutron stars at temperatures T≅109–1010 K.
Zh. éksp. Teor. Fiz. 114, 385–397 (August 1998)
Published in English in the original Russian journal. Reproduced here with stylistic changes by the Translation Editor. 相似文献
3.
Mats Lindroos Bob McElrath Christopher Orme Thomas Schwetz 《The European Physical Journal C - Particles and Fields》2009,64(4):549-560
We propose a method to measure the neutrino mass kinematically using beams of ions which undergo beta decay. The idea is to
tune the ion beam momentum so that in most decays, the electron is forward moving with respect to the beam, and only in decays
near the endpoint is the electron moving backwards. Then, by counting the backward moving electrons one can observe the effect
of neutrino mass on the beta spectrum close to the endpoint. In order to reach sensitivities for m
ν
<0.2 eV, it is necessary to control the ion momentum with a precision better than δ
p/p<10−5, identify suitable nuclei with low Q-values (in the few to ten keV range), and one must be able to observe at least
O(1018)\mathcal{O}(10^{18})
decays. 相似文献
4.
K. Blaum G. Bollen F. Herfurth A. Kellerbauer H.-J. Kluge M. Kuckein E. Sauvan C. Scheidenberger L. Schweikhard 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):245-248
The cyclotron frequencies of singly charged carbon clusters Cn
+ (n ≥ 2) were measured with the Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN. The present limit of mass accuracy δm/m = 1.2 . 10-8 and the extent of the mass-dependent systematic shift (δm/m)sys = 1.7(0.6) . 10-10/u
. (m - m
ref) of the setup were investigated for the first time. In addition, absolute mass measurements by use of pure clusters of the
most abundant carbon isotope 12C are now possible at ISOLTRAP.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"Present address: CERN, CH-1211 Geneva 23, Switzerland; e-mail: klaus.blaum@cern.ch 相似文献
5.
I. V. Gaidaenko A. V. Novikov V. A. Novikov A. N. Rozanov M. I. Vysotsky 《JETP Letters》1998,67(10):761-765
The large top-quark mass is responsible for the enhancement of the oblique radiative corrections in SUSY models. We present
analytical formulas for these corrections to the W-boson mass m
W
and to the Z
l
+
l
−-coupling constants. A comparison with the result of the standard model fit is made.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 10, 723–726 (25 May 1998)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
6.
I. V. Sokolov 《Journal of Experimental and Theoretical Physics》2009,109(2):207-212
Dirac’s analysis of radiation reaction force in classical electrodynamics suggested that a 4-momentum not collinear with 4-velocity
could be introduced for a radiating electron. This would be equivalent to renormalization of the electron mass as an operator
relating these 4-vectors. Dirac also pointed to an arbitrary choice made in deriving the Lorentz-Abraham-Dirac (LAD) equation.
It was shown that renormalization substantially modifies the LAD equation under the additional requirement that the standard
relativistic relation ℰ2 = p
2
c
2 + m
2
c
4 holds for the renormalized energy and momentum. The renormalized LAD equation is more rigorous than the LAD equation, because
the drawbacks of the latter are eliminated, and is simpler than a well-known approximation of the LAD equation. The renormalized
LAD equation appears to be better suited for numerical simulations of processes in ultrahigh-intensity laser-pulse fields. 相似文献
7.
V. V. Skobelev 《Journal of Experimental and Theoretical Physics》1998,86(5):850-853
The dominant one-loop electron contribution to the mass operator of an axion in a crossed field in the asymptotic limits of
the parameters q
2/m
e
2
and
is calculated. The corresponding electromagnetic mass of the axion is compared with the quantum-chromodynamic mass due to
mixing with π. Expressions are derived for the probability of pair creation a→e
+
e
−, and the fundamental conclusion is reached that refractive effects are present in the propagation of an axion in an external
electromagnetic field.
Zh. éksp. Teor. Fiz. 113, 1558–1565 (May 1998) 相似文献
8.
M. W. Evans 《Foundations of Physics Letters》1995,8(1):83-92
The longitudinal vacuum fieldB
(3)
is an experimental observable which produces by magnetization a well-defined square-root beam power density dependence. Its longitudinal polarization implies that the helicities of the photon are +1, 0, and –1, and that the little group of the Poincaré group is the rotation group 0(3) of a massive boson. The mass of the photon (m) is therefore related directly toB
(3)
through the Proca equation, and it is concluded that experimental evidence forB
(3)
is also evidence for finitem. 相似文献
9.
The polarization operator of an axion in a degenerate gas of electrons occupying the ground-state Landau level in superstrong
magnetic fields H≫H
0=m
e
2
c
3/eℏ=4.41×1013 G is investigated in a model with a tree-level axion-electron coupling. It is shown that a dynamic axion mass, which can
fall within the allowed range of values 10−5 eV≲m
a≲102 eV, is generated under the conditions of strongly magnetized neutron stars. As a result, the dispersion relation for axions
is appreciably different from that in a vacuum.
Zh. éksp. Teor. Fiz. 115, 3–11 (January 1999) 相似文献
10.
The purpose of the present study was to provide a reliable value for the specific grain-boundary resistivity ρSGBR of Ni metal. New results are presented on the room-temperature electrical resistivity of nanocrystalline (nc) Ni metal samples produced by electrodeposition with various grain sizes. These resistivity data were compared with previous reports on nc-Ni and all results were analysed according to the procedure of Andrews [Phys. Lett. 19, 558 (1965)] who found that the resistivity increment due to grain boundaries is proportional to the grain-boundary surface area per unit volume which is, on the other hand, inversely proportional to the grain size. It is pointed out that the grain size directly accessible by transmission electron microscopy imaging is the relevant parameter for the evaluation of ρSGBR whereas the crystallite size deduced from X-ray diffraction line broadening leads to an underestimation of ρSGBR because coherency-breaking intragrain defects not contributing significantly to the resistivity also cause a line broadening. From the evaluation of the nc-Ni resistivity data at room temperature, we find that 4.45·10?16?Ω·m2?ρSGBR(Ni)?6.2·10?16?Ω·m2 and our upper bound agrees exactly with the most recent calculated value in the literature. 相似文献
11.
The dynamics of a point-like relativistic particle with respect of the proper time is formulated on the hyperboloid p
2
0–p
2=M
2
c
2. The Hamilton-Jacobi equations on the hyperboloid are derived for the particles with mass (M
2=m
2, m>0), for the particles with zero-mass (M=0, m>0), and for the neutrino. It is shown, in a certain factorization of the momentum, the model can be identified with Nambu's three-dimensional phase space formalism. A first quantized version of the model is formulated according to a canonical scheme of quantization (Schrödinger quantization scheme). 相似文献
12.
Stefan E. Huber Daniel Süß Michael Probst Andreas Mauracher 《Molecular physics》2019,117(17):2233-2240
ABSTRACTWe report total electron-impact ionisation cross sections (EICSs) of cisplatin, its hydrolysis products and transplatin in the energy range from threshold to 10?keV using the binary-encounter-Bethe (BEB) and its relativistic variant (RBEB), and the Deutsch-Märk (DM) methods. We find reasonable agreement between all three methods, and we also note that the RBEB and the BEB methods yield very similar (almost identical) results in the considered energy range. For cisplatin, the resulting EICSs yield cross section maxima of 22.09?×?10?20?m2 at 55.4?eV for the DM method and 18.67?×?10?20?m2 at 79.2?eV for the (R)BEB method(s). The EICSs of monoaquated cisplatin yield maxima of 12.54?×?10?20?m2 at 82.8?eV for the DM method and of 9.74?×?10?20?m2 at 106?eV for the (R)BEB method(s), diaquated cisplatin yields maxima of 7.56?×?10?20?m2 at 118.5?eV for the DM method and of 5.77?×?10?20?m2 at 136?eV for the (R)BEB method(s). Molecular geometry does not affect the resulting EICS significantly, which is also reflected in very similar EICSs of the cis- and trans-isomer. Limitations of the work as well as desirable future directions in the research area are discussed. 相似文献
13.
T. Wujec A. Jazgara J. Halenka J. Musielok 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(3):405-408
Stark broadening measurements and calculations of the Paschen γ spectral line of hydrogen ( λ = 1.094[:
MU
:]
m) are reported. Investigations have been performed at plasma electron densities between 1.4×10
15
cm
-3
and 3.7×10
15
cm
-3
. As the light source a wall-stabilized arc operated in a helium-hydrogen gas mixture at atmospheric pressure has been applied.
The radiation of the plasma emitted from nearly homogeneous plasma layers in end-on direction, was measured with the use of
a grating spectrometer equipped with a charge coupled device (CCD) detector. The radiance calibration was carried out against
light outputs originating from a tungsten strip radiation standard. The measured FWHM are compared with results of our calculations based on computer simulation techniques (full computer simulation method --
FCSM). Our broadening data are also compared with results of other theoretical approaches (MM-method, quasi-static approximation)
and with experimental data obtained at electron densities about one order of magnitude larger than ours.
Received 21 January 2003 Published online 24 April 2003
RID="a"
ID="a"e-mail: wujec@uni.opole.pl 相似文献
14.
A. Pelc W. Sailer P. Scheier N.J. Mason T.D. Märk 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,20(3):441-444
Using a high resolution electron energy monochromator low energy electron attachment to formic acid is studied for the first
time by means of mass spectrometric detection of the product anions. The largest dissociative electron attachment (DA) cross-section
produces HCOO
-+H with weaker channels for OH- and O- becoming apparent at higher incident energies.
Received 23 January 2002 and Received in final form 9 February 2002 Published online 13 September 2002 相似文献
15.
16.
M. Ya. Amus’ya A. I. Mikhailov I. A. Mikhailov 《Journal of Experimental and Theoretical Physics》1998,86(2):299-304
Inelastic photon scattering by helium atoms and helium-like ions with simultaneous excitation of the two-electron transition
1s
2→2s
2 is examined in the nonrelativistic energy range I≪ω≪m (I is the ionization potential, ω is the photon energy, m is the electron mass, and ℏ=c=1). The electrons are assumed to be moving in the Coulomb field of the nucleus, and the electron-electron interaction is
taken into account in the lowest perturbation order. The differential and total cross sections of the process and the autoionization
width of the 2s
2 energy level are calculated. The numerical value of the autoionization width is found to agree with the results of the more
rigorous calculations of other researchers.
Zh. éksp. Teor. Fiz. 113, 539–549 (February 1998) 相似文献
17.
J. Kramář 《Czechoslovak Journal of Physics》1965,15(3):190-200
This article deals with the calculation of the influence of the magnetic field upon the electric current of a thermionic converter presupposing the approach to conditions in a low-pressure cesium converter. The distribution of the starting velocities of the emitted electrons is considered firstly as independent of the angle from the perpendicular to the emitter plane, and secondly according to the cosine law.The magnetic field effect from the converter current is calculated and compared with the calculations in the papers by Schock [1] and Block [2]; the effect of the external magnetic field is verified by measurements on a solar thermionic converter prototype.Symbols
F=I/I
0
factor of current reduction from magnetic field effect
-
¯F
value of factorF (when the magnetic field is not constant)
-
I [A/m2]
density of collector current (real current influenced by magnetic field)
-
I
0 [A/m2]
theoretical density of collector current (in ideal case equals electron emission current)
-
T
e
[°K]
electron gas temperature; assumed equal to emitter temperatureT
E
[°K]
-
B[Wb/m2]
magnetic induction (field)
-
D[m]
distance from emitter to collector
-
R[m]
radius of electrodes, emitter and collector
-
r[m]
variable radius in the limits 0 toR
-
V [m/s]
random velocity of electron
-
v
xz
[m/s]
component of the vectorV inx-z plane
-
v
m
=2kT
E
/m
most probable velocity in the velocity distribution according to Maxwell and Boltzmann
-
w-v
xz
/v
m
relatively expressed electron velocityv
xz
-
the angle of any vectorV
-
[m]
radius of circular electron path
-
n [m–3]
number (density) of electrons with certain value of random velocity
-
n
0 [m–3]
total electron number (density)
-
n
1 [m–3]
number of electrons returned to emitter by means of magnetic field
-
N
0 [m–2s–1]
total flow of thermionic electrons emitted from a unit surface
-
N
1 [m–2s–1]
partial flow of electrons returned to emitter
-
P=N
1/N0
relatively expressed flow of electrons returned to emitter (whenB = const.)
-
¯P
mean value ofP (whenB const.)
-
F
cos,
,P
cos,
values asF,¯F,P,¯P in case of velocity distribution according to cosine law
-
m=9·107×10–31 [gk]
electron mass
-
e=1·60×10–19 [C]
electron charge
-
k×1·38×10–23 [J/grad]
Boltzmann's constant
-
0
1·257×10–6 [H/Vs] permeability of vacuum 相似文献
18.
G. Fabritius G. Flik J. Golczewski D. Herlach G. Jünemann M. Krenke K. Maier A. P. Pathak H. Rempp A. Seeger W. Sigle E. Widmann D. W. Cooke 《Hyperfine Interactions》1986,31(1-4):229-234
By means of π+/μ+ channelling, positive pions (π+) implanted intoTa, Mo, andW are investigated up to high temperatures. A striking observation is that the channelling effect disappears in a rather narrow
temperature interval centred at 0.26 (Ta) to 0.51 (W) of the melting temperature. From studies of π+ trapping by oxygen atoms inTa estimates for the low-temperature π+ diffusivity inTa [D
π(23K)=1.4·10−10±0.3 m2s−1,D
π(47K)=5.7·10−10±0.3 m2s−1] as well as for the binding enthalpy of π+ to 0 atoms (H
B=7·10−2 eV) have been obtained. The diffusion data are in reasonable agreement with the theory of phonon-assisted tunnelling. 相似文献
19.
A. Kellerbauer G. Bollen J. Dilling S. Henry F. Herfurth H.-J. Kluge E. Lamour D. Lunney R.B. Moore C. Scheidenberger S. Schwarz G. Sikler J. Szerypo 《Hyperfine Interactions》2001,132(1-4):507-511
With the Penning trap mass spectrometer ISOLTRAP, close to 200 nuclides have already been investigated and their masses determined
with a typical relative precision of δm/m=10−7. Recently, ISOLTRAP's beam preparation system was replaced by an RFQ ion beam cooler and buncher. The principle and the characteristics
of this new beam preparation system will be presented. It is planned to use ions of various carbon clusters C+
n
(n>1) as reference ions for mass measurements. Apart from negligible molecular binding energies, these clusters have masses
that are exact multiples of the unified atomic mass unit. This will allow ISOLTRAP to carry out absolute mass measurements
as well as to investigate possible mass-dependent systematic errors. The results of tests of the production, transport, and
trapping of such carbon clusters will be presented.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
Results are presented from the first stage of studies on the passage of an electron beam with energy 100–500 eV in a magnetic
field of 300–700 Oe through the curvilinear solenoid of the KRéL unit, the latter being a prototype of the closing segment
of the Drakon stellarator system, in the plasma-beam discharge regime. The ion density at the end of the curvilinear part
of the chamber, n
i
≈8×108–1010 cm−3, the electron temperature T
e
≈4–15 eV, and the positions at which the beam hits the target for different distances from it to the electron source are determined
experimentally. The motion of the electron beam is computationally modeled with allowance for the space charge created by
the beam and the secondary plasma. From a comparison of the experimentally measured trajectories and trajectories calculated
for different values of the space charge, we have obtained an estimate for the unneutralized ion density of the order of 5×107 cm−3.
Zh. Tekh. Fiz. 69, 22–26 (February 1999) 相似文献