共查询到20条相似文献,搜索用时 15 毫秒
1.
The electric dipole moment function of the OH radical in the ground electronic state is constructed for internuclear distances R [0, ]. The electric dipole moment function is represented as a piecewise continuous function satisfying physically exact asymptotes and experimental values of the electric dipole moment and its derivatives for equilibrium positions of nuclei of the radical. The Padé form for the electric dipole moment function of the OH radical is also approximated. Electric dipole moment functions obtained are compared with the results of ab initio calculations. 相似文献
2.
P.H. Chankowski M. Krawczyk J. Żochowski 《The European Physical Journal C - Particles and Fields》1999,11(4):661-672
We present an up-to-date analysis of the constraints the precision data impose on the (CP-conserving) Two Higgs Doublet Model of type II with emphasis on the possible existence of very light neutral (pseudo)scalar
Higgs boson with mass below 20–30 GeV. We show that even in the presence of such light particles, the 2HDM(II) can describe
the electroweak data with the precision comparable to that given by the SM. Particularly interesting lower limits on the mass
of the lighter neutral CP-even scalar are obtained in the scenario with light CP-odd Higgs boson and large .
Received: 8 June 1999 / Published online: 14 October 1999 相似文献
3.
A. Akeroyd A. Arhrib E. Naimi 《The European Physical Journal C - Particles and Fields》2000,12(3):451-460
We compute the fermionic radiative contributions to the decay in the framework of models with two Higgs doublets (2HDM), for the case of an on-shell and off-shell W. We show that, in the majority of the cases, current measurements of the parameter suggest and such decays could invalidate current charged Higgs searches or aid detection in the region . We find that the radiative corrections may approach 50% for small values of .
Received: 22 April 1999 / Published online: 10 December 1999 相似文献
4.
J. Kuckei C. Dib A. Faessler T. Gutsche S. G. Kovalenko V. E. Lyubovitskij K. Pumsa-ard 《Physics of Atomic Nuclei》2007,70(2):349-357
We calculate the neutron electric dipole form factor induced by the CP-violating θ term of QCD within a perturbative chiral quark model which includes pion and kaon clouds. On this basis, we derive the neutron
electric dipole moment and the electron—neutron Schiff moment. From the existing experimental upper limits on the neutron
electric dipole moment, we extract constraints on the θ parameter and compare our results with other approaches.
The text was submitted by the authors in English. 相似文献
5.
I.D. Petrov V.L. Sukhorukov E. Leber H. Hotop 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,10(1):53-65
The effect of the polarization of the atomic core by the outer electron on near threshold photoionization of excited alkali
atoms Ak(np) (Ak = Na-Cs; n=3-6) is investigated. Partial and total cross-sections for photo-ionization of the np-electron were computed utilizing the configuration interaction technique with Pauli-Fock atomic orbitals (CIPF) and including
the long range core polarization potential (CP). To calculate the core polarization potential the variational principle is
applied. Comparison with previous theoretical results and with available experimental data is made for the total cross-section
, for the electron angular distribution parameter , for the ratio of the reduced electric dipole matrix elements and for the phase shift difference , associated with the d-wave and s-wave continua, respectively. In the comparison, new experimental results for , , and , measured for laser-excited, polarized 39K(4p
3/2) atoms, have been included.
Received 21 July 1999 and Received in final form 14 October 1999 相似文献
6.
W. Bernreuther L. Chen I. García M. Perelló R. Poeschl F. Richard E. Ros M. Vos 《The European Physical Journal C - Particles and Fields》2018,78(2):155
We study the potential of future lepton colliders to probe violation of the CP symmetry in the top quark sector. In certain extensions of the Standard Model, such as the two-Higgs-doublet model (2HDM), sizeable anomalous top quark dipole moments can arise, which may be revealed by a precise measurement of top quark pair production. We present results from detailed Monte Carlo studies for the ILC at \(500 \hbox { GeV}\) and CLIC at \(380 \hbox { GeV}\) and use parton-level simulations to explore the potential of high-energy operation. We find that precise measurements in \(e^+e^- \rightarrow t\bar{t}\) production with subsequent decay to lepton plus jets final states can provide sufficient sensitivity to detect Higgs-boson-induced CP violation in a viable two-Higgs-doublet model. The potential of a linear \(e^+e^-\) collider to detect CP-violating electric and weak dipole form factors of the top quark exceeds the prospects of the HL-LHC by over an order of magnitude. 相似文献
7.
Analytical expressions are obtained for the angular distributions and spin asymmetries of the processes of elastic electromagnetic
and electroweak scattering of high energy electrons on polarized/unpolarized proton target with account of C-, P- and T/CP-invariance violating anapole and electric dipole moments, as well as neutral weak electric, magnetic and axial form factors
of the proton. Behavior of the P- and T- odd spin asymmetries is studied in dependence of the electron’s energy and scattering angle and proton form factors parameters. 相似文献
8.
里德堡原子由于具有体积大、寿命长、易极化及在外电场中能级易于操控等特点, 已经成为了目前物理学领域研究的热点之一. 本文在磁光阱中实验测量了铯原子15P3/2和16P3/2态的Stark光谱,根据光谱给出了15P3/2和16P3/2|m|=1/2 Stark态在0-1400 V/cm场强范围适用的Stark 能量和偶极矩的经验性解析表达式; 用数值方法求解薛定谔方程获得了这些态的Stark能量、偶极矩和电子几率密度分布. 电子几率密度分布定性说明了计算的偶极矩矢量的方向是正确的. 计算的Stark能量、偶极矩与实验结果相一致. 相似文献
9.
We predict the charged lepton electric dipole moments in the split fermion scenario in the framework of the two Higgs doublet
model. We observe that the numerical value of the muon (tau) electric dipole moment is of the order of the magnitude of 10-22 e cm (10-20 e cm) and there is an enhancement in the case of two extra dimensions, especially for the tau lepton electric dipole moment.
Received: 15 July 2005, Published online: 6 October 2005 相似文献
10.
Analytic expressions of the dyadic Green's function of an arbitrary electric current source embedded in a general biisotropic sphere are presented at first, and the radiation characteristics of an electric dipole antenna placed on the surface of a biisotropic sphere lens are examined. The effects of the electric-and the magnetic-coefficients (
e
and
m
) of biisotropic medium on the radiation patterns of electric dipole antenna are investigated in detail. 相似文献
11.
M.P. Rekalo E. Tomasi-Gustafsson 《The European Physical Journal A - Hadrons and Nuclei》2003,16(4):563-567
We discuss the applicability of pQCD to the elastic scattering of electrons on protons and deuterons. We analyze the Q2-dependence of the reduced deuteron form factor, taking into account the recent data on the electric proton form factor and
we find that the value of the QCD-scale parameter Λ differs essentially from the value Λ = 0.1 GeV, previously found using
the dipole parametrization of the electromagnetic nucleon form factors GE and GM. Moreover, the predicted scaling behavior of the reduced deuteron form factor cannot be recovered in the Dirac and Pauli
representations for the nucleon electromagnetic form factors.
Received: 14 October 2002 / Accepted: 12 November 2002 / Published online: 11 March 2003
RID="a"
ID="a"Permanent address: National Science Center KFTI, 310108 Kharkov, Ukraine.
RID="b"
ID="b"e-mail: etomasi@cea.fr
Communicated by V.V. Anisovich 相似文献
12.
M. Sandoli A. Boiano L. Campajola A. De Rosa A. D'Onofrio G. Inglima M. La Commara A. Ordine D. Pierroutsakou V. Roca M. Romano M. Romoli M. Trotta F. Rizzo F. Amorini S. Tudisco 《The European Physical Journal A - Hadrons and Nuclei》1999,6(3):275-288
We report on the results obtained from the study of the 32S +74Ge deep inelastic reaction at incident energy E= 320 MeV. High-energy γ-rays were detected in an array of 6 seven-pack BaF2 clusters. Coincidence with complex fragments detected in 12 three-stage telescopes ensured the selection of peripheral reaction
events. In order to investigate the pre-equilibrium dipole strength excitation two independent analyses were performed. In
the first analysis the energy spectra of the γ-rays were evaluated in the statistical model framework while in the second
one the γ-ray fragment angular correlation with respect to the nuclear spin vector of the composite system was studied. Both
methods indicate the excitation of dipole strength in the highly deformed dinucleus and provide dipole resonance parameter
sets that are in good agreement with each other.
Received: 24 March 1999 / Revised version: 17 May 1999 相似文献
13.
Analytic expressions for cross sections and spin asymmetries characterizing processes of elastic weak, electromagnetic, and
electroweak scattering of a neutrino (antineutrino) having electromagnetic moments on a polarized or an unpolarized proton
target were obtained with allowance for the C-, P-, and T/CP-violating anapole and electric dipole moments and the neutral weak, electric, magnetic, and axial form factors of the proton,
and these expressions were analyzed. The behavior of spin asymmetries was studied versus the energy and form-factor parameters. 相似文献
14.
Using coupled cluster singles and doubles linear response theory and the d-aug-cc-pVTZ basis set extended with a 3s3p2d1f1g set of midbond functions, the interaction induced electric dipole polarisability surface of the CO–Ar van der Waals complex is computed. Combining this surface with accurate intermolecular potential energy and electric dipole surfaces, the pressure and dielectric second virial coefficients of the complex are calculated by a classical statistical approach. Excellent agreement with experimental results (to within the experimental error bars) is obtained for the pressure second virial coefficient over a range of temperatures. No previous experimental or theoretical investigations have been carried out for the dielectric second virial coefficient, B ε(T), which is estimated to be about 1.9 cm6 mol??1 at room temperature. This value results from a balance of terms due to the interaction induced electric dipole polarisability (predominant at high temperatures) and orientational electric dipole contributions. 相似文献
15.
Xian-Qiao Yu 《The European Physical Journal C - Particles and Fields》2009,64(4):529-532
We study the nucleon electromagnetic form factors in a quark–gluon core model framework, which can be viewed as an extension
of the Isgur–Karl model of baryons. Using this picture we derive nucleon electromagnetic dipole form factors at low Q
2 and the deviation from the dipole form at high Q
2, that are consistent with the existing experimental data. 相似文献
16.
Utilizing the methods of chiral effective field theory we present an analysis of the electromagnetic NΔ-transition current in the framework of the non-relativistic “small scale expansion” (SSE) to leading-one-loop order. We
discuss the momentum dependence of the magnetic dipole, electric quadrupole and Coulomb quadrupole transition form factors
up to a momentum transfer of Q2 < 0.3GeV^2. Particular emphasis is put on the identification of the role of chiral dynamics in this transition. Our analysis
indicates that there is indeed non-trivial momentum dependence in the two quadrupole form factors at small Q2 < 0.15GeV^2 arising from long-distance pion physics, leading, for example, to negative radii in the (real part of the) quadrupole
transition form factors. We compare our results with the EMR(Q2) and CMR(Q2) multipole ratios from pion-electroproduction experiments and find a remarkable agreement up to four-momentum transfer of
Q2 ≈ 0.3GeV^2. Finally, we discuss the chiral extrapolation of the three transition form factors at Q2 = 0, identifying rapid changes in the (real part of the) quark mass dependence of the quadrupole transition moments for pion
masses below 200MeV, which arise again from long-distance pion dynamics. Our findings indicate that dipole extrapolation methods
currently used in lattice QCD analyses of baryon form factors are not applicable for the chiral extrapolation of NΔ quadrupole transition form factors. 相似文献
17.
2- and 3-photon electric dipole transitions for the harmonic oscillator are shown to have zero intensity. This is extended to the general cases of Δv?=?n and Δv?=?n???2 for n-photon transitions. Although not proved in general, it seems likely that all multiphoton transition moments vanish. This suggests that electric dipole multiphoton transition intensity is due to anharmonicity. 相似文献
18.
D. Azinović S. Milosević G. Pichler M.C. van Hemert R. Düren 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,6(3):333-341
We investigated the photochemical formation of lithium-rare-gas excimers in the 3 state through the reaction of Li2(2(C)) and the ground-state rare-gas atom. Lithium-rare-gas vapor mixture was prepared in the heat-pipe oven. We populated the
2(C)state of the Li2 molecule using the XeCl excimer laser wavelength at 308 nm or the PTP dye laser wavelength at about 335 nm. The 3-1 transitions were observed with peaks at 414, 420 and 435 nm for LiAr, LiKr and LiXe, respectively. We estimated thermally
averaged rate constants for these photochemical reactions, which are cm3s-1 for LiAr, cm
3
s-1 for LiKr and cm3s-1 for LiXe. Ab initio potential-energy curves and transition dipole moments for LiKr were calculated applying the SCF MRDCI method. Available data
for the LiAr and LiKr excimers are presented, including potential-energy curves, electronic transition dipole moments, and
spectroscopic constants. Possible photochemical formation of these molecules in the excited states is discussed. We performed
the quantum-mechanical spectral simulations of the LiAr and LiKr 3-1 transitions, using ab initio potential-energy curves.
Received: 2 October 1998 / Received in final form: 25 January 1999 相似文献
19.
We test the possible dipole anisotropy of the Finslerian cosmological model and the other three dipole-modulated cosmological models, i.e. the dipole-modulated ΛCDM, wCDM and Chevallier–Polarski–Linder (CPL) models, by using the recently released Pantheon sample of SNe Ia. The Markov chain Monte Carlo (MCMC) method is used to explore the whole parameter space. We find that the dipole anisotropy is very weak in all cosmological models used. Although the dipole amplitudes of four cosmological models are consistent with zero within the \begin{document}$1\sigma$\end{document} ![]()
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uncertainty, the dipole directions are close to the axial direction of the plane of the SDSS subsample in Pantheon. This may imply that the weak dipole anisotropy in the Pantheon sample originates from the inhomogeneous distribution of the SDSS subsample. A more homogeneous distribution of SNe Ia is necessary to constrain the cosmic anisotropy. 相似文献
20.
Dae Sung Hwang Bum-Hoon Lee 《The European Physical Journal C - Particles and Fields》1999,6(4):663-670
We calculate the form factors and of and V, , and of transition matrix elements by using the factorization formalism of perturbative QCD in the region . In the limit of , , and , the results show that and are of monopole type, V, and of dipole type, and of a combination of monopole and dipole types with dipole type dominating.
Received: 20 April 1998 / Published online: 5 October 1998 相似文献