共查询到20条相似文献,搜索用时 265 毫秒
1.
Hee-Jung Lee Chang Ho Hyun Chang-Hwan Lee Hyun-Chul Kim 《The European Physical Journal C - Particles and Fields》2006,45(2):451-457
We investigate the ΔS = 0 effective chiral Lagrangian from the instanton vacuum. Based on the ΔS = 0 effective weak Hamiltonian from the operator product expansion and renormalization group equations, we derive the strangeness-conserving
effective weak chiral Lagrangian from the instanton vacuum to order
and the next-to-leading order in the 1/Nc expansion at the quark level. We find that the quark condensate and a dynamical term which arise from the QCD and electroweak
penguin operators appear in the next-to-leading order in the 1/Nc expansion for the ΔS = 0 effective weak chiral Lagrangian, while they are in the leading order terms in the ΔS = 1 case. Three different types of form factors are employed and we find that the dependence on the different choices of
the form factor is rather insensitive. The low-energy constants of the Gasser-Leutwyler type are determined and discussed
in the chiral limit.
Arrival of the final proofs: 2 December 2005
PACS:
12.40.-y, 14.20.Dh 相似文献
2.
Gerald Rosen 《Central European Journal of Physics》2011,9(1):45-48
Without Higgs field interaction, accurate pole mass values are obtained for the charged leptons and quarks from a Z3-symmetric linear superposition self-interference of the Dirac fields in the effective free-field Lagrangian. The charged
lepton and quark pole masses evidence the discrete Z3 symmetry, the theoretical-experimental deviations δm/m are $
\mathcal{O}
$
\mathcal{O}
(10−5) for all three charged leptons, and the quark pole masses are in very satisfactory overall agreement with the experimental
data. 相似文献
3.
Hanxin He 《Zeitschrift fur Physik C Particles and Fields》1995,69(1):287-295
We study the effective quark-gluon coupling at low-energy scale, which is defined as the amplitude of a quark emitting or
absorbing a gluon with some momentum at low-energy scale. This amplitude is determined from the fermionic three-point Green’s
functions of QCD including the leading order contributions of nonperturbative condensates through use of the operator-product
expansion. By this approach, we discuss the relationship between the constituent quark and the quark of QCD Lagrangian, and
estimate the scale of chiral symmetry breaking and the size of a constituent quark in participating the strong interaction
process, such as form factors and radii. 相似文献
4.
This paper is a sequel of a previous one (Scalar mesons in a chiral quark model with glueball, Eur. Phys. J. A 8, 567 (2000)) where an attempt to construct an effective U(3)×U(3)-symmetric meson Lagrangian with a scalar glueball was made. The glueball was introduced by using the dilaton model on
the base of scale invariance. The scale invariance breaking because of current quark masses and the scale anomaly of QCD,
reproduced by the dilaton potential, was taken into account. However, in the previous paper, the scale invariance breaking
because of the terms like h
φφ2 and h
σ
, where φ and are the pseudoscalar and scalar isosinglets, was not taken into account. These terms are produced by the part of the 't Hooft
interaction that is connected with gluon anomalies. Allowing for the scale invariance breaking by these terms has a decisive
effect on the quarkonium-glueball mixing and noticeably changes the widths of glueball strong decays. Taking account of this
additional source of the scale invariance breaking and its implications are the subject of the present work. It is also shown
that in the decay of a glueball into four pions, the channel with two ρ-resonances dominates.
Received: 11 January 2001 / Accepted: 25 January 2001 相似文献
5.
Buchalla G. Catà O. Rahn R. Schlaffer M. 《The European Physical Journal C - Particles and Fields》2013,73(10):1-17
The effective Lagrangian with scalar and vector resonances that might result from new strong physics beyond the SM is formulated and studied. In particular, the scalar resonance representing the recently discovered 125-GeV boson is complemented with the SU(2) L+R triplet of hypothetical vector resonances. Motivated by experimental and theoretical considerations, the vector resonance is allowed to couple directly to the third quark generation only. The coupling is chiral-dependent and the interaction of the right top quark can differ from that of the right bottom quark. To estimate the applicability range of the effective Lagrangian the unitarity of the gauge boson scattering amplitudes is analyzed. The experimental fits and limits on the free parameters of the vector resonance triplet are investigated. 相似文献
6.
Yu. A. Simonov 《Physics of Atomic Nuclei》2001,64(3):548-553
Starting from the QCD Lagrangian and separating background and valence degrees of freedom, one arrives at the effective Lagrangian for valence quarks and gluons. Each term in the Lagrangian contains a product of valence quark and gluon operators acting at the end of the fundamental or adjoint string, made of the background field. A simple procedure is described how to obtain from the Lagrangian self-coupled equations for quark and gluon Green's function. 相似文献
7.
Zhi-Gang Wang 《The European Physical Journal C - Particles and Fields》2007,52(3):553-560
In this article, we study the vertices DDV and D*DV with the light-cone QCD sum rules. The strong coupling constants gDDV and fD*DV play an important role in understanding the final-state re-scattering effects in the hadronic B decays. They are related
to the basic parameters β and λ respectively in the heavy quark effective Lagrangian; our numerical values are smaller than
the existing estimations.
PACS 12.38.Lg; 13.20.Fc 相似文献
8.
S. Fajfer S. Prelovšek P. Singer 《The European Physical Journal C - Particles and Fields》1999,6(3):471-476
Using the factorization scheme for the nonleptonic D → > VV
0 weak amplitudes, we classify all diagrams which arise in D → Vγ decays and calculate them with the help of the hybrid model which combines the heavy quark effective theory and the chiral
Lagrangian approach. Thus we determine the long distance contribution to the amplitudes of Cabibbo allowed and Cabibbo suppressed
D → Vγ decays. The calculation of the expected range of the branching ratios of nine different D → Vγ channels is compared with results of other approaches. The present work establishes an increase of the parity violating contribution
in these decays in comparison with previous analyses. 相似文献
9.
We construct an effective Lagrangian for the hadronic decays of a heavy excited s-wave-spin-one quarkonium Ψ′ into a lower s-wave-spin-one state Ψ. We show that reasonable fits to the measured invariant mass spectra in the charmonium and bottomonium systems can be obtained within this framework. The mass dependence of the various terms in the Lagrangian is discussed on the basis of a quark model. 相似文献
10.
11.
Within the theory of SU(2) and SU(3) Yang-Mills gauge fields, the effective Lagrangian is derived with allowance for the modification in the gluon and quark spectra that arises in a constant magnetic field with constant potentials. 相似文献
12.
The possibility that pairs of quarks will form diquark clusters in the regime above deconfinement transition for hadron matter
at finite density is revisited. Here we present the results on the diquark-diquark (dq-dq) interaction in the framework of
constituent quark model taking account of spin, isospin and color degrees of freedom in the spirit of generalized Pauli principle.
By constructing the appropriate spin and color states of the dq-dq clusters we compute the expectation values of the interaction
Hamiltonian involving pairwise quark—quark interaction. We find that the effective interaction between two diquark clusters
is quite sensitive to different configurations characterized by color and spin states, obtained after the coupling of two
diquark states. The value of the coupling parameter for a particular color—spin state, i.e., -3, 1 is compared to the one
obtained earlier by Donoghue and Sateesh,Phys. Rev.
D38, 360 (1988) based on the effective Φ4-theory. This new value of λ derived for different color-spin dq-dq states, may lead to several important implications in
the studies of diquark star and diquark gas. 相似文献
13.
B. G. Zakharov 《JETP Letters》1997,65(8):615-620
The induced gluon radiation of a high-energy quark in a finite-size QCD medium is studied. For a sufficiently energetic quark
produced inside a medium we find the radiative energy loss ΔE
q∝L
2, where L is the distance traveled by quark in the medium. It has a weak dependence on the initial quark energy E
q. The L
2 dependence turns to L
1 as the quark energy decreases. Numerical calculations are performed for a cold nuclear matter and a hot quark-gluon plasma.
For a quark incident on a nucleus we predict ΔE
q
≈0.1E
q
(L/10fm)
β
, with β close to unity.
Pis’ma Zh. éksp. Teor. Fiz. 65, No. 8, 585–589 (25 April 1997)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
14.
Yu. A. Simonov 《Few-Body Systems》1998,25(1-3):45-54
An effective quark Lagrangian is derived from the action of quantum chromodynamics by means of averaging over vacuum gluonic
fields. In the limit of large and by keeping, for simplicity, the lowest-order gluonic correlator one obtains nonlinear equations for the quark propagator,
exhibiting scalar confinement. The connection to the quark zero mode density is discussed.
Received July 7, 1997; revised December 1, 1997; accepted for publication February 17, 1998 相似文献
15.
The effective chiral Lagrangian is derived from QCD in the framework of the field correlator method. It contains the effects of both confinement and chiral symmetry breaking due to a special structure of the resulting quark mass operator. It is shown that this Lagrangian describes light pseudoscalar mesons, and Gell-Mann-Oakes-Renner relations for pions, eta and K mesons are reproduced. The spectrum of radial excitations of pions and K mesons is found and compared to experimentally known masses. 相似文献
16.
TheJ/ψπ → -DD*,-DD,-D*D* and -DD* cross-sections as a function of √s are evaluated in a QCD sum rule calculation. We study the Borel
sum rule for the four point function involving pseudoscalar and vector meson currents, up to dimension four in the operator
product expansion. We find that our results are close to those obtained with quark exchange models. We also find that the
quark condensate gives the main nonperturbative contribution to the cross-section. 相似文献
17.
18.
Wang Qing 《中国物理C(英文版)》1999,23(2):155-164
From view point of modem field theory, all theories for realistic interaction are effective, which come from some more elementary theory. One main feature of effective theory is that it include infinite number of interaction terms. Effective theory is different with standard renormalizable field theory. Here, we focus on a class of special effective theory-effective chiral Lagrangian in strong interaction, discuss its features and present status of its development. We don't involve heavy quark effechvefield theory and N'RQCD and the combinahon of these theories and effective chiral Lagrangian. 相似文献
19.
The studies of superconductivity, dual superconductivity and color superconductivity have been undertaken through the breaking
of supersymmetric gauge theories which automatically incorporate the condensation of monopoles and dyons leading to confining
and superconducting phases. Constructing the total effective Lagrangian of N=2 SU(2) gauge theory with N
f
=2 quark multiplets and quark chemical potential at classical and quantum levels, it has been demonstrated that baryon number
symmetry is spontaneously broken as a consequence of the SU(2) strong gauge dynamics and the color superconductivity dynamically takes space at the non-SUSY vacuum. 相似文献
20.
We derive a strong coupling effective Lagrangian describing Wilson lines coupled to quark bilinears. Wilson line and dynamical quark mass are studied in mean field approximation. A second-order finite-temperature chiral phase transition is found at zero chemical potential μ. For μ≠0 this transition becomes a first-order one. 相似文献