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1.
D. Bardin 《The European Physical Journal C - Particles and Fields》2002,24(3):373-383
We study predictions for the reaction . The complete one-loop corrections are taken into account and higher order contributions, in particular those for the observed
real photons, are added whenever necessary. The event generator MC, a general-purpose Monte Carlo generator for the process based on the method of exclusive exponentiation, is used as the environment. We extend its applicability to the process ,, where the observation of at least a single is required. The exponentiation is implemented in much the same way as for the s-channel process alone. In particular, all photonic effects present in the case of W exchange, which cannot be included in the s-channel exponentiation scheme, are calculated to a finite order only. The real hard photon matrix element is calculated up
to . Leading logarithmic contributions of the two-loop corrections and one-loop photonic corrections accompanying real single-photon
emission are included. The electroweak corrections are calculated with the DIZET library of the ZFITTER package. Numerical
tests and predictions for typical observables are presented.
Received: 30 October 2001 / Revised version: 5 March 2002 / Published online: 22 May 2002 相似文献
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R. Barate et al. 《The European Physical Journal C - Particles and Fields》2001,19(2):213-227
4.
We consider the τ leptonic decay $\tau\rightarrow
l\bar{\nu}_{l}\nu_{\tau}$ in the framework of the littlest
Higgs (LH) model and calculate the corrections of new particles to
this decay. We find that the contributions of the charged scalars
can be safely ignored and the LH model is in perfect agreement
with the universality of the couplings of the SU gauge bosons
to the leptonic charged currents. The corrections of the LH model
to the τ leptonic decay $\tau\rightarrow
l\bar{\nu}_{l}\nu_{\tau}$ are not sensitive to the parameter
c, but depend strongly on the parameters f and x. The
precision measured data about the τ leptonic decay demand
that the parameter f approximately equal 3.5 TeV and x>0.1, while agree with the general expectation based on other
phenomenological
explorations. 相似文献
5.
New short baseline neutrino experiments open new possibilities of high precision study of different neutrino processes. We present here results of the calculation of the polarization of final nucleon in elastic NC $\nu _\mu (\bar \nu _\mu )$ -nucleon scattering. In a numerical analysis the sensitivity to the different choices of the axial and axial strange form factors is examined. Measurements of the polarization of the final proton in elastic e-p scattering drastically changed our knowledge about the electromagnetic form factors of the proton. From measurement of the nucleon polarization in the NC elastic scattering a new additional information about the axial G A (Q 2) and the strange axial G s A (Q 2) form factors of the nucleon could be inferred. 相似文献
6.
Massimo Lenti 《Hyperfine Interactions》2018,239(1):51
The NA62 experiment at CERN SPS was designed to measure the \(BR(K^{+}\rightarrow \pi ^{+}\nu \bar \nu )\) with a decay-in-flight technique. NA62 took data in 2016, 2017 and 2018. Statistics collected in 2016 allowed NA62 to reach the Standard Model sensitivity and to show the proof of principle of the experiment. The preliminary result from the 2016 data set is presented. 相似文献
7.
We consider the Schrödinger equation with a combination of Deng–Fan-type and harmonic terms. To solve the corresponding differential equation, we split the equation to two parts: the parent and the perturbation terms. We use the Nikiforov–Uvarov technique to solve the parent part. For the perturbation part, we apply the series expansion method. Next, using the calculated wave function, we investigate some bottom and charm mesons within the Isgur–Wise function formalism. We present especially semileptonic \({\bar{B} \rightarrow D\ell \bar{\nu}}\) and \({\bar{B}_{s} \rightarrow D_s \ell \bar{\nu }}\) decay widths, branching ratios and \({|V_{cb}|}\) (element of the CKM matrix). Masses of some pseudoscalar mesons are also indicated. Comparisons of our results with experimental values and other approaches are included. 相似文献
8.
E7 is a room temperature nematic liquid crystal that presents both a high temperature nematic-to-isotropic transition and a high positive dielectric anisotropy. The optical characteristics of this liquid crystal have been widely investigated in the visible region of the spectrum, while less experiments have been performed in the middle infrared spectral region, where, nevertheless, potential applications are important. We investigate the self-focusing of a middle infrared laser beam when it passes through a film of E7. We also take into account the heating of the liquid crystal film caused by the partial absorption of the laser light by means of a thermographic technique. A theoretical interpretation of the self-focusing phenomenon is given in terms of the reorientation of the molecules with respect to their unperturbed direction and an estimation of the average value of the elastic constants of the liquid crystal is given by fitting the experimental data with the theoretical model.Received: 16 April 2003PACS:
42.70.Df Liquid crystals - 42.65.-k Nonlinear optics - 42.55.Lt Gas lasers including excimer and metal-vapor lasers 相似文献
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K. Azizi R. Khosravi V. Bashiry 《The European Physical Journal C - Particles and Fields》2008,56(3):357-370
Taking into account the gluon correction contributions to the correlation function, the form factors relevant to the rare
decays are calculated in the framework of the three-point QCD sum rules, where X stands for axial vector particle, AV(D
s1), and vector particles, V(D
*,D
s
*). The total decay width as well as the branching ratio of these decays are evaluated using the q
2 dependent expressions of the form factors. A comparison of our results with the predictions of the relativistic constituent
quark model is presented. 相似文献
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Using the formulas for the distribution with non-zero lepton mass and experimentally determined form factors, we calculate the spectra and branching fractions for l = e, and . We obtain the results and . Since we used the experimentally measured form factors, these results are independent of theoretical models of the form factors. 相似文献
13.
A. Piotrowska E. Papis E. Kamińska K. Gołaszewska T. Pustelny E. Maciak Z. Opilski 《The European physical journal. Special topics》2008,154(1):149-152
Layered structure for the detection and measuring of
gaseous ammonia have been presented. The presented sensor structures hale
Bern developed on the base of thin ZnO and Au/Cr layers deposited on a glass
substrate. The technological as well as optical properties of the elaborated
sensing structures have been discussed. 相似文献
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J. Rymarczyk D. Machura J. Ilczuk 《The European physical journal. Special topics》2008,154(1):191-194
Bismuth ferrite, one of a few multiferroics, has attracted
much attention for many decades since 1960. BiFeO3 (BFO) belongs to
perovskite class of complex oxides. BFO is one of only a few materials in
which (anti)ferromagnetism and ferroelectricity coexis in room temperature. Authors prepared BiFeO3 ceramics by solid state reaction method. The
synthesized powders were characterized by X-ray diffraction method.
Thermogravimetric and differential thermal analysis were investigated. The
microstructure of the BFO ceramics was investigated by means of scanning
transmission electron microscopy, and the ferroelectric characteristic of
BFO ceramics was demonstrated. BFO is very interesting ceramic material for
potential applications in the memory devices, sensors, satellite
communications, optical filters and smart devices. 相似文献
16.
Double clad aluminosilicate optical fibre doped with
neodymium ions was obtained. Aluminosilicate glasses with low silica (25 mol%)
content possess very good optical, thermal and mechanical properties. Simultaneously they are characterized by high solubility
of rare
earth elements. A set of physical measurements including: DTA, DSC, DL
analysis, absorption spectroscopy and thermo-physical properties (thermal
stability parameters, refractive index, thermal expansion coefficient,
microhardness, density and molar volume) were determined. Double-crucible
drawing technique was applied to obtain neodymium doped double clad optical
fibre with
. Luminescence spectra of aluminosilicate glass and fibre
doped with Nd3 + ions are presented. 相似文献
17.
《Physics of Atomic Nuclei》2005,68(4):549-553
On the 70th Anniversary of Yurii Antonovich Simonov
70th birthday of Yuri $\overset{\lower0.5em\hbox{$\overset{\lower0.5em\hbox{ Antonovich Simonov 相似文献18.
19.
We study the spectrum of the minimal supersymmetric extension of the Carroll–Field–Jackiw model for Electrodynamics with a topological Chern–Simons-like Lorentz-symmetry violating term. We identify a number of independent background fermion condensates, work out the gaugino dispersion relation and propose a photonic effective action to consider aspects of confinement induced by the SUSY background fermion condensates, which also appear to signal Lorentz-symmetry violation in the photino sector of the action. Our calculations of the static potential are carried out within the framework of the gauge-invariant but path-dependent variables formalism which are alternative to the Wilson loop approach. Our results show that the interaction energy contains a linear term leading to the confinement of static probe charges. 相似文献
20.
Z. Was 《The European Physical Journal C - Particles and Fields》2005,44(4):489-503
One of the necessary steps in constructing a high-precision option of KKMC, a Monte Carlo program for the high-precision simulation
of fermion pair production at LEP and Linear Collider energies, was to make a careful study of the appropriate matrix elements
calculated from QED and the complete standard model. In particular, the installation of the double bremsstrahlung matrix element
for the process
into the scheme of coherent exclusive exponentiation (CEEX) was necessary. In the CEEX scheme one has to define an extrapolation
and/or reduction procedure to enable the use of the matrix elements for kinematical configurations with a large number of
outgoing particles. The process under study is particularly interesting because of the gauge cancellation of contributions
for photon emission from incoming fermion lines and t-channel W. The QED U(1) gauge properties require terms of the triple and quartic gauge couplings to be taken into consideration as
well. A natural separation of the complete amplitude into gauge invariant parts was found and is among the main results of
the paper. Each part has a well defined physical interpretation, which after partial integration over phase space provides
infrared singular, leading-log, next-to-leading-log, and other terms. Contributions related to the triple and quartic gauge
coupling of W (extracted with the help of an expansion around the contact W-interaction) have been ordered as well. The separation can be of broader interest; it originates from the rigorous calculation
of matrix elements; it visualizes, in the language of spin amplitudes, the properties of factorization necessary for the common
multi-process picture. For example, the multiple photon algorithm of PHOTOS, based on the parton shower-like approach, profits
from similar considerations. These somewhat speculative aspects of the calculation will be mentioned in the paper as well.
Received: 24 April 2005, Revised: 22 July 2005, Published online: 11 October 2005
Supported in part by the EU grant MTKD-CT-2004-510126, in patnership with the CERN Physics department, and Polish State Committee
for Scientific Research (KBN) grant 2 P03B 091 27 for years 2004-2006. 相似文献