共查询到20条相似文献,搜索用时 15 毫秒
1.
D. Bećirević Ph. Boucaud V. Giménez V. Lubicz M. Papinutto 《The European Physical Journal C - Particles and Fields》2004,37(3):315-321
We report our results for the bag parameter B
K
obtained from the quenched simulations on the lattice with Wilson fermions for three values of the lattice spacing. We implemented the method by which no subtraction of the mixing with other four-fermion
operators is needed. Our final result, in terms of the renormalization group invariant bag parameter, is
.Received: 9 July 2004, Revised: 27 July 2004, Published online: 21 September 2004 相似文献
2.
With the decay constants of D and D
s
mesons measured in experiment recently, we revisit the study of the bound states of quark and antiquark in B and D mesons in the relativistic potential model. The relativistic bound state wave equation is solved numerically. The masses,
decay constants and wave functions of B and D mesons are obtained. Both the masses and decay constants obtained here can be seen as consistent with the experimental data.
The wave functions can be used in the study of B and D meson decays. 相似文献
3.
J. P. Guedes S. Azevedo M. Machado 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,80(1):127-135
We have studied, through ab initio calculations, the stability of 60° and 120° boron nitride nanocones containing mono and
multiple boron, nitrogen, and
carbon vacancies. The stability of the vacancies as well as the structures reconstruction mechanism have been investigated.
Our results indicate that the
stability of the cones presenting such vacancies strongly depends on growth conditions. We have also found that multiple vacancies
display formation energies that
are comparable, and in some cases, even lower to the ones presented by monovacancies. Therefore, our results allow us to conclude
that the formation energy does not
depend on the vacancy size. Finally, for 120° cones, we can verify that the stability of the boron and nitrogen vacancies
depends on the position where the atom has
been removed. 相似文献
4.
The difference of vector and axial-vector charged current correlators is analyzed by means of QCD sum rules. The contribution of 10-dimensional 4-quark condensates is calculated and its value is estimated within the framework of the factorization hypothesis. It is compared to the result obtained from an operator fit of Borel sum rules in the complex q
2-plane, calculated from experimental data on hadronic
-decays. This fit gives accurate values of the light quark condensate and the quark-gluon mixed condensate. The size of the high-order operators and the convergence of the operator series are discussed.Received: 10 May 2004, Revised: 7 September 2004, Published online: 18 November 2004 相似文献
5.
Alakabha Datta David London Joaquim Matias Makiko Nagashima Alejandro Szynkman 《The European Physical Journal C - Particles and Fields》2009,60(2):279-284
Certain B
s
0→V
1
V
2 decays (V
i
is a vector meson) can be related by flavor SU(3) symmetry to corresponding B
d
0→V
3
V
4 decays. In this paper, we show that the final-state polarization can be predicted in the B
s
0 decay, assuming polarization measurements of the B
d
0 decay. This can be done within the scenario of penguin annihilation (PA), which has been suggested as an explanation of the
unexpectedly large transverse polarization in B→φ
K
*. PA is used to estimate the breaking of flavor SU(3) symmetry in pairs of decays. Two of these for which PA makes a reasonably
precise prediction of the size of SU(3) breaking are (B
s
0→φ
φ,B
d
0→φ
K
0*) and (
). The polarization measurement in the B
d
0 decay can be used to predict the transverse polarization in the B
s
0 decay and will allow for testing of PA as well as the other assumptions in the analysis. 相似文献
6.
The spatial string tension across a crossover from the low-temperature phase to the high-temperature phase is computed in
QCD with two flavors of nonperturbatively improved Wilson fermions at small lattice spacing a ∼ 0.12 fm. We find that in the low-temperature phase spatial string tension agrees well with zero-temperature string tension.
Furthermore, it does not show increasing for temperatures up to T = 1.36T
pc, the highest temperature considered. Our results agree with some theoretical predictions.
The text was submitted by the authors in English. 相似文献
7.
P. V. Zakharov M. D. Starostenkov S. V. Dmitriev 《Bulletin of the Russian Academy of Sciences: Physics》2017,81(11):1322-1326
The conditions for the existence of discrete breathers (DBs) in biatomic crystals of AB and A 3 B composition are established, and their properties are studied by means of molecular mechanics using the examples of CuAu and Pt3Al, respectively. The phonon spectra of the crystals are analyzed, and a gap in the phonon spectrum of CuAu is obtained via considerable homogeneous elastic strain. There is a gap in the phonon spectrum of the Pt3Al crystal at zero strain, due to the considerable difference between the atomic weights of its components. The frequencies at which discrete breathers can exist in the considered crystals are determined. The energy localized on different types of DBs is estimated. The propagation of a current pulse through Pt3Al resulting in the excitation of DBs with mild nonlinearity is simulated. 相似文献
8.
V. V. Pokropivny L. I. Ovsyannikova S. V. Kovrigin 《Physics of the Solid State》2007,49(12):2335-2341
A general approach is formulated to the design of crystal-forming fullerene-like clusters X n Y n from which zeolite-like covalent crystals based on IV-IV, III-V, and II-VI binary semiconductor compounds with diamond-like sp 3 bonds can be constructed and synthesized by means of copolymerization through faces. A number of the smallest sized crystal-forming boron nitride clusters are constructed, such as the B12N12, B16N16, B18N18, B24N24, B36N36, and B 60N60 fulborenes. The optimized configurations, electronic structures, charge transfers, band gaps, total energies, cohesive energies, and electron density maps of the clusters are calculated using the spin-restricted Hartree-Fock method in the 6–31G basis set. Comparative calculations of the B60N60 fulborene with the use of the density functional theory method have demonstrated that the spin-restricted Hartree-Fock method in the 6–31G basis set is optimum from the standpoint of the accuracy and efficiency. 相似文献
9.
D. Ebert R. N. Faustov V. O. Galkin 《The European Physical Journal C - Particles and Fields》2011,71(12):1825
The mass spectra of charmonia, bottomonia and B
c
mesons are calculated in the framework of the QCD-motivated relativistic quark model based on the quasipotential approach.
The dynamics of heavy quarks and antiquarks is treated fully relativistically without application of the nonrelativistic v
2/c
2 expansion. The known one-loop radiative corrections to the heavy quark potential are taken into account perturbatively. The
heavy quarkonium masses are calculated up to rather high orbital and radial excitations (L=5, n
r
=5). On this basis the Regge trajectories are constructed both in the total angular momentum J and radial quantum number n
r
. It is found that the daughter trajectories are almost linear and parallel, while parent trajectories exhibit some nonlinearity
in the low mass region. Such nonlinearity is most pronounced for bottomonia and is only marginal for charmonia. The obtained
results are compared with the available experimental data, and a possible interpretation of the new charmonium-like states
above open charm production threshold is discussed. 相似文献
10.
Representations of the sℓq(2) algebra are constructed in the space of polynomials of real (complex) variable for qN=1. The spin addition rule based on eigenvalues of Casimir operator is illustrated on few simplest cases and conjecture for general case is formulated. 相似文献
11.
S.?R.?Gevorkyan A.?N.?Sissakian A.?V.?Tarasov H.?T.?Torosyan O.?O.?Voskresenskaya 《Physics of Atomic Nuclei》2010,73(6):937-940
The final-state interaction of pions in K e4 decay allows to obtain the value of the isospin and angular-momentum-zero ππ scattering length a 0 0 .We take into account the electromagnetic interaction of pions and isospin-symmetry-breaking effects caused by different masses of neutral and charged pions and estimate the impact of these effects on the procedure of scattering-length extraction from K e4 decays. 相似文献
12.
Teng Wang Tianbo Liu Da-Xin Zhang Bo-Qiang Ma 《The European Physical Journal C - Particles and Fields》2011,71(9):1758
We investigate the rare decays \(B_{c} \rightarrow D_{s}(1968)\ell \overline{\ell}\) and \(B_{c}\rightarrow D_{s}^{*}(2317) \ell \overline{\ell}\) in the framework of the light-cone quark model (LCQM). The transition form factors are calculated in the space-like region and then analytically continued to the time-like region via exponential parametrization. The branching ratios and longitudinal lepton polarization asymmetries (LPAs) for the two decays are given and compared with each other. The results are helpful for investigating the structure of B c meson and for testing the unitarity of CKM quark mixing matrix. All these results can be tested in the future experiments at the LHC. 相似文献
13.
M. A. Braun 《The European Physical Journal C - Particles and Fields》2009,63(2):287-296
The lowest order pomeron loop is calculated for the leading conformal weight with full dependence of the triple-pomeron vertex
on intermediate conformal weights. The loop is found to be convergent. Its contribution to the pomeron Green function begins
to dominate already at rapidities 10–15. The pomeron pole renormalization is found to be quite small due to a rapid fall of
the triple-pomeron vertex with rising conformal weights. 相似文献
14.
Zhi-Gang Wang 《The European Physical Journal C - Particles and Fields》2009,63(1):115-122
In this article, we assume that there exists a scalar
Ds*[`(D)]s*D_{s}^{\ast}{\bar{D}}_{s}^{\ast}
molecular state in the J/ψ
φ invariant mass distribution, and we study its mass using the QCD sum rules. The predictions depend heavily on the two criteria
(pole dominance and convergence of the operator product expansion) of the QCD sum rules. The value of the mass is about
MDs*[`(D)]s*=(4.43±0.16)M_{D_{s}^{\ast}{\bar{D}}_{s}^{\ast}}=(4.43\pm0.16)
GeV, which is inconsistent with the experimental data. The
Ds*[`(D)]s*D_{s}^{\ast}{\bar{D}}_{s}^{\ast}
is probably a virtual state and is not related to the meson Y(4140). Another possibility, such as a hybrid charmonium, is not excluded. 相似文献
15.
The hierarchical structure of fermion masses of the Standard Model is explained in split fermion models by localizing the
fermions at different points in an extra dimension. We consider split fermion models with two bulk scalars compactified on an orbifold. In the static case we find analytical expression for the localizer. We also address the issue of stability of the localizer.
We also find exact solutions for the fermion zero modes. We explore the parameter space of the model. We find ample opportunity
for construction of phenomenologically viable theories exist. 相似文献
16.
17.
Qi Song Honggang Liu Yuefeng Zhao Yan Zeng Gangcheng Wang Kang Xue 《International Journal of Theoretical Physics》2016,55(3):1679-1685
We investigate quantum Fisher information (QFI) for s u(2) atomic coherent states and s u(1, 1) coherent states. In this work, we find that for s u(2) atomic coherent states, the QFI with respect to \(\vartheta ~(\mathcal {F}_{\vartheta })\) is independent of φ, the QFI with respect to \(\varphi (\mathcal {F}_{\varphi })\) is governed by ??. Analogously, for s u(1,1) coherent states, \(\mathcal {F}_{\tau }\) is independent of φ, and \(\mathcal {F}_{\varphi }\) is determined by τ. Particularly, our results show that \(\mathcal {F}_{\varphi }\) is symmetric with respect to ?? = π/2 for s u(2) atomic coherent states. And for s u(1,1) coherent states, \(\mathcal {F}_{\varphi }\) also possesses symmetry with respect to τ = 0. 相似文献
18.
The objective of this paper is to construct a multiple p-adic q-L-function of two variables which interpolates multiple generalized q-Bernoulli polynomials. By using this function, we solve a question of Kim and Cho. We also define a multiple partial q-zeta function which is related to the multiple q-L-function of two variables. Finally, we give a finite-sum representation of the multiple p-adic q-L-function of two variables and prove a multiple q-extension of the generalized formula of Diamond and Ferrero-Greenberg. 相似文献
19.
M. van Leeuwen 《The European Physical Journal C - Particles and Fields》2009,61(4):569-574
We present selected recent results of multi-hadron correlation measurements in azimuth and pseudorapidity at intermediate
and high p
T
in Au+Au collisions at
, from the STAR experiment at RHIC. At intermediate p
T
, measurements are presented that attempt to determine the origin of the associated near-side (small Δφ) yield at large pseudo-rapidity difference Δη that is found to be present in heavy ion collisions. In addition, results are reported on new multi-hadron correlation measures
at high-p
T
that use di-hadron triggers and multi-hadron cluster triggers with the goal to constrain the underlying jet kinematics better
than in the existing measurements of inclusive spectra and di-hadron correlations. 相似文献
20.
We find an integral transform realizing the connection between the s-parameterized quasidistributions of a quantum state and its corresponding tomogram, which looks like a Radon transform. We
show that the kernel of the new Radon transform is a Gaussian function with s-parameterized dispersion. It can be considered as a broadened delta-function appeared in the standard Radon transform. 相似文献