共查询到20条相似文献,搜索用时 31 毫秒
1.
The signs of the experimental values of the multipole-mixture parameters δ are compared with the signs of ℛ = Σa
i
μ
i
for (2+02−2+01) and (2+03−2+01) transitions and with the signs of = Σa
i
[(μ
i
+ μ
kν
) or (μ
kπ
− 1/2)] for (2+21−2+01) transitions in nonspherical even-even nuclei, where a
i
is the contribution of the ith pair of quasiparticles to the wave function for 2+02, 2+03, and 2+21 single-phonon states according to the quasiparticle-phonon model and μ is the magnetic moment for the corresponding Nilsson
state.
Original Russian Text ? A.M. Demidov, L.I. Govor, V.A. Kurkin, I.V. Mikhailov, 2009, published in Yadernaya Fizika, 2009,
Vol. 72, No. 2, pp. 228–235. 相似文献
2.
Zhi-Gang Luo Xiao-Lin Chen Xiang Liu Shi-Lin Zhu 《The European Physical Journal C - Particles and Fields》2009,60(3):403-411
Stimulated by recent observations of the excited bottom–strange mesons B
s1 and B
s2*, we calculate the semileptonic decays
, which is relevant for the exploration of the potential of searching these semileptonic decays in experiment. 相似文献
3.
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
4.
本文利用脉冲紫外激光(UV)选择激发氨分子到?1A″2电子激发态的两个最低振动能级ν′2=0和ν′2=1(ν2振动),然后检测新生态H原子的飞行谱(TOF),研究了氨分子的光碎片动力学。光谱证实了最近所测的离解能D00(H-NH2)=4.645eV;绝大多数生成的NH2(X2B1)基处于非振动激发,但是具有围绕a惯性轴的高度转动激发。通过NH3(?)的ν′2=1光离解产生的NH2(X)基具有较高的内部激发,并且显示了在N=Ka转动能级上的反转布居。
关键词: 相似文献
5.
Zhi-Gang Wang 《The European Physical Journal C - Particles and Fields》2008,58(2):245-250
We study the final-state rescattering effects in the decay B
0→η
c
K
*. The numerical results indicate that the corrections are comparable with the contribution from the naive factorizable amplitude,
and the total amplitudes can accommodate the experimental data. 相似文献
6.
Yu-Ming Wang M. Jamil Aslam Cai-Dian Lü 《The European Physical Journal C - Particles and Fields》2009,59(4):847-860
The exclusive weak decay of Λ
b
→Λ
γ and Λ
b
→Λ
l
+
l
− are investigated in the Appelquist–Cheng–Dobrescu model, which is an extension of the standard model in the presence of universal
extra dimensions. Employing the transition form factors obtained in the light-cone sum rules, we analyze how the invariant-mass
distribution, the forward–backward asymmetry and the polarization asymmetry of the Λ baryon of these decay modes can be used to constrain the only additional free parameter with respect to the standard model,
namely, the radius, R, of the extra dimension. Our results indicate that the Kaluza–Klein modes can lead to approximately 25% suppression of the
branching ratio of Λ
b
→Λ
γ; however, their contributions can bring about 10% enhancement to the decay rate of Λ
b
→Λ
l
+
l
−. It is shown that in the present scenario the zero position of the forward–backward asymmetry of Λ
b
→Λ
μ
+
μ
− is sensitive to the compactification parameter R, while the measurement of polarizations of Λ baryon in the Λ
b
decays are not a useful tool to provide any valuable information for the universal extra-dimension model. 相似文献
7.
R. Riahi Ph. Teulet Z. Ben Lakhdar A. Gleizes 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,56(1):61-66
The weighted total cross section (WTCS) theory has been applied to the
electron-H2 collision to obtain excitation, ionisation and dissociation
cross section and rate coefficients of the X 1Sg+^{1}\!\Sigma _{g}^{+}, c
3Pu^{3}\!\Pi _{u}, a 3Sg+^{3}\!\Sigma _{g}^{+}, e $^{3}\!\Sigma
_{u}^{+}$^{3}\!\Sigma
_{u}^{+} and B′
1Su+^{1}\!\Sigma _{u}^{+} states. Calculation has
been performed in the temperature range 1500 K–15000 K. Rate coefficients
are calculated from WTCS assuming Maxwellian energy distribution functions
for electrons and heavy particles. Thermal equilibrium results are presented
and fitting parameters (a, b and c) are given for each reaction rate
coefficient: k(θ) = a (θb)
exp(-c/θ). 相似文献
8.
The e
+
e
− → π
+
π
−
π
+
π
− cross section is calculated for energies of 0.65 ≤ √s ≤ 1 GeV in the framework of the generalized hidden local symmetry model. The calculations are compared with the data of CMD-2
and BaBaR. It is shown that the inclusion of heavy isovector resonances ρ(1450) and ρ(1700) is necessary for reconciling calculations
with the data. It is found that, at √s ≈ 1 GeV, the contributions of the above resonances are much larger, by a factor of 30, than the ρ(770) one, and amount to
a considerable fraction ∼0.3–0.6 of the latter at √s ∼ m
ρ.
The text was submitted by the authors in English. 相似文献
9.
A. V. Pashchenko A. A. Shemyakov V. P. Pashchenko V. A. Turchenko V. K. Prokopenko Yu. F. Revenko Yu. V. Medvedev B. M. éfros G. G. Levchenko 《Physics of the Solid State》2009,51(6):1193-1203
Magnetoresistive ceramic samples La0.7Ca0.3 − x
Sr
x
MnO3 ± δ sintered at temperatures of 1150 and 1350°C are investigated using X-ray diffraction, microscopic, resistance, and magnetic
(χ, 55Mn NMR) measurements. The specific features of the influence of the composition on the type and parameters of the perovskite
structure, its imperfection, the porous crystallite structure, the metal-semiconductor and ferromagnetic-paramagnetic phase
transitions, the 55Mn NMR spectra, and the magnetoresistance effect are established. The magnetic phase diagram is constructed. The conclusions
are drawn regarding the nonuniformity of the distribution of ions and vacancies around manganese involved in the high-frequency
electron-hole exchange (Mn3+ ai Mn4+) and the nanostructured separation of the perovskite structure containing anion and cation vacancies, with the concentrations
and magnetoresistance effect decreasing and the lattice parameters and phase transition temperatures increasing as calcium
is replaced by strontium.
Original Russian Text ? A.V. Pashchenko, A.A. Shemyakov, V.P. Pashchenko, V.A. Turchenko, V.K. Prokopenko, Yu.F. Revenko,
Yu.V. Medvedev, B.M. éfros, G.G. Levchenko, 2009, published in Fizika Tverdogo Tela, 2009, Vol. 51, No. 6, pp. 1127–1136. 相似文献
10.
E. P. Shabalin 《Physics of Atomic Nuclei》2010,73(11):1908-1915
The unitarization of the amplitude for the decay process K
10 → π+π− and allowance for the rescattering of final-state pions in the decay process K
+ → π+π+π− make it possible to evaluate, by using the parameters extracted from data on K → 2π decays, the K
+ → π+π+π− decay width. The result agrees with the experimental width value at a level of a few percent. Allowance for corrections for
higher order terms of the momentum expansion of the amplitude for the decay process K
+ → π+π+π− leads to the slope-parameter value of g
++−th = 0.2182, which agrees with its experimental counterpart, g
++−exp = 0.2154 ± 0.0035. 相似文献
11.
S. N. Morozov U. Kh. Rasulev 《Bulletin of the Russian Academy of Sciences: Physics》2008,72(7):902-905
The mass spectra of secondary cluster ions Bi
n
+ (n = 1–9) from bismuth sputtered by (6–21) keV Au
m
− (m = 1–9) and Bi
m
− (m = 1–5) cluster ions have been investigated. New features of manifestation of dense nonlinear cascades and thermal spikes
have been revealed. It is concluded that the thermal spike regime makes a significant contribution to the mechanism of formation
of small cluster ions, containing up to seven atoms for a bismuth target. 相似文献
12.
用脉冲直流放电产生Xe原子亚稳态5p56s[3/2]2和5p56s′[1/2]0.在单光子28000-42000cm-1能量范围内,结合飞行时间质谱技术获得Xe原子共振增强激发光谱.光谱分析表明,所有谱线来源于Xe原子5p56s[3/2]2和5p56s′[1/2]0两个亚稳态吸收单个光子向偶宇称np′、nf′自电离Rydberg态序列的跃迁.实验观测到许多新的自电离能级,并获得更精确和系统的能级位置和量子亏损值数据. 相似文献
13.
DELPHI Collaboration W. Adam T. Adye E. Agasi I. Ajinenko R. Aleksan G. D. Alekseev P. P. Allport S. Almehed S. J. Alvsvaag et al. 《Zeitschrift fur Physik C Particles and Fields》1995,69(1):561-573
An analysis is presented of inclusiveπ
0 production inZ
0 decays measured with the DELPHI detector. At low energies,π
0 decays are reconstructed by using pairs of converted photons and combinations of converted photons and photons reconstructed
in the barrel electromagnetic calorimeter (HPC). At high energies (up to
) the excellent granularity of the HPC is exploited to search for two-photon substructures in single showers. The inclusive
differential cross section is measured as a function of energy forqq andbb events. The number ofπ
0’s per hadronicZ
0 event isN(π
0)/Z
had
0
=9.2±0.2(stat)±1.0(syst) and forbb events the number ofπ
0’s is N(π
0)/bb=10.1±0.4(stat)±1.1(syst). The ratio of the number ofπ
0’s inbb events to hadronicZ
0 events is less affected by the systematic errors and is found to be 1.09±0.05±0.01. The measuredπ
0 cross sections are compared with the predictions of different parton shower models. For hadronic events, the peak position
in theξ
p=ln(1/xp) distribution isξ*
p
=3.90
−0.14
+0.24
. The average number ofπ
0’s from the decay of primary B hadrons is found to be N(B→π
0
X)/B hadron=2.78±0.15(stat)±0.60(syst). 相似文献
14.
We calculate the branching ratios of pure annihilation type decays B 0 →Ds- (K2*)+ and Bs → a2 using the perturbative QCD approach based on k T factorization. The branching ratios are predicted to be (60.6 +17.3+4.3+3.2 16.5 10.4 2.1 )× 10-6 for B0 →Ds- (K2*)+ , (1.1 +0.4+0.1+0.1-0.4-0.2-0.1 )×10-6 for Bs → 0a20 and (2.3 +0.8+0.2+0.1-0.8-0.4-0.1 )×10-6 for Bs→D-a2+ . They are large enough to be measured in the ongoing experiment. Due to the shortage of contributions from penguin operators, there are no direct CP asymmetries for these decays in the Standard Model. We also derive simple relations among these decay channels to reduce theoretical uncertainties for the experiments, to test the accuracy of theory, and to search for a signal of new physics. 相似文献
15.
基于北京谱仪收集的4.03GeV质心系能量下e+e-对撞数据,分析τ±τ±→e±+π±+nπ0+ν's(n=0,1,2)事例,给出分支比值Br(τ±→π±ντ)=(11.64±0.49+0.76-0.73%,Br(τ±→π±π0ντ)=(24.00±1.34+1.36-1.30%,Br(τ±→π±2π0ντ)=(9.39±1.68+1.69-1.66%. 相似文献
16.
利用脉冲激光溅射-超声分子束载带方法制备气相硼羰基络合物正离子. 采用红外光解离光谱研究了B(CO)3+、B(CO)4+ 和B2(CO)4+的振动光谱. 研究结果表明B(CO)3+具有非常强的B-CO键,无法直接获得其红外光解离光谱. 对B(CO)4+的光解离光谱研究表明该离子是一个B(CO)3+和CO之间弱相互作用络合物. 其中B(CO)3+核具有平面D3h对称性结构,中心硼具有稳定的8电子组态. B2(CO)4+具有平面的D2h对称性结构,其中的B-B键包含一个σ键和半个π键. 自然轨道能量分解分析(EDA-NOCV)表明在B(CO)3+和B2(CO)4+中的B-CO成键作用中OC→B(σ)要比B→CO(π)反馈作用强. 相似文献
17.
18.
19.
20.
P.F. Bernath R.W. Field B. Pinchemel Y. Lefebvre J. Schamps 《Journal of Molecular Spectroscopy》1981,88(1):175-193
Laser excitation spectra have been recorded for Ca79Br and Ca81Br in the spectral region 600–630 nm. The use of a 1-m monochromator as a narrow band pass filter (1–2 cm?1) has allowed rotational analysis of the 0-0, 1-1, and 2-2 bands of the B2Σ+ - X2Σ+ transition and the 0-0 and 1-1 bands of the A2Π - X2Σ+ transition. A few additional lines of the 0-1, 1-2, 1-0, and 2-1 bands of the B-X system were used to obtain band origins for vibrational analysis. The main constants for Ca79Br are (in cm?1):
0 | 15 958.41 (10) | 16 383.137 (6) | |
285.732 (9) | 288.56 (20) | 285.747 (9) | |
0.840 (4) | — | 0.954 (4) | |
0.094466141 (30) | 0.0957343 (20) | 0.0965151 (20) | |
0.000403551 (40) | 0.0004327 (20) | 0.0004483 (15) | |
(spin-rot.) | 0.00301484 (50) | — | 0.068767 (79) |
— | ?0.066834 (64) | — | |
— | 59.175 (1) | — |