共查询到20条相似文献,搜索用时 15 毫秒
1.
Andrea Raspini 《International Journal of Theoretical Physics》1988,27(8):1007-1017
The wave functions of the 18 ground-state light baryons are calculated in the quark model. The space wave functions are obtained by means of a (confining) hyperspherical harmonic potential in a nonrelativistic Hamiltonian. The different flavors (up, down, strange) are treated as identical particles. 相似文献
2.
《Nuclear Physics A》1998,634(3):335-367
A family of simply solvable covariant quark models for the baryons is presented. With optimal parameter choices the models reproduce the empirical spectra of the baryons in all flavor sectors to an accuracy of a few percent. Complete spectra are obtained for all states of the strange, charm and beauty hyperons with L ⩽2. The magnetic moments and axial coupling constants of the ground state baryons correspond to those of conventional quark models. We construct current-density operators tjat are consistent with empirical nucleon form factors at low and medium momenta. 相似文献
3.
B.H Kellett 《Annals of Physics》1974,87(1):60-94
The Bethe-Salpeter equation for the relativistic three quark bound state is solved for an instantaneous interaction in the ladder approximation. The particular solution obtained is valid for simple potentials in both the weak and strong binding situations. The general method for calculating matrix elements for the interaction of the bound state with an external electromagnetic field is presented. Particular attention is paid to the emergence of the nonrelativistic quark model interaction as the lowest order approximation in a perturbative expansion in the inverse quark mass. Relativistic corrections to this approximation are investigated, and their importance is seen to depend on the quark mass. For light quarks these corrections can be large, and to reproduce the proton magnetic moment, for instance, a substantial anomalous moment is necessary. The model has several encouraging features. The form factors with a harmonic potential have an asymptotic k?2 behavior, and the relativistic corrections to the SU(6) results for the form factors are of the correct order of magnitude. 相似文献
4.
V. E. Lyubovitskij A. Faessler Th. Gutsche M. A. Ivanov J. G. Krner 《Progress in Particle and Nuclear Physics》2003,50(2):329-339
We present a summary of results for exclusive decays of single and double heavy-flavored baryons in the relativistic three-quark model. 相似文献
5.
S. Migura D. Merten B. Metsch H. -R. Petry 《The European Physical Journal A - Hadrons and Nuclei》2006,28(1):41-53
We calculate mass spectra of charmed baryons within a relativistically covariant quark model based on the Bethe-Salpeter equation
in instantaneous approximation. Interactions are given by a linearly rising three-body confinement potential and a flavor-dependent
two-body force derived from QCD instanton effects. This model has already been successfully applied to the calculation of
light flavor baryon spectra and is now extended to heavy baryons. Within the same framework we compare the results to those
obtained with the more conventional one-gluon exchange potential. 相似文献
6.
D. Ebert R. N. Faustov V. O. Galkin A. P. Martynenko V. A. Saleev 《Zeitschrift fur Physik C Particles and Fields》1997,76(1):111-115
In the framework of the relativistic quasipotential quark model the mass spectrum of baryons with two heavy quarks is calculated. The quasipotentials for interactions of two quarks and of a quark with a scalar and axial vector diquark are evaluated. The bound state masses of baryons with are computed. 相似文献
7.
Seiji Ono 《Nuclear Physics B》1976,107(3):522-534
We use the non-relativistic harmonic oscillator quark model to study electromagnetic properties of baryons. We show that the wave function radius can be determined very precisely (within 2 ~ 3% error) studying the electromagnetic mass difference. The obtained value (R2 = 2.75 GeV?2) is much smaller than that which is widely believed (6 GeV? ? R2 ? 16 GeV?2).We use this value to study photo- and electro-production processes. It is shown that if this small R2 is used and if the amplitude is calculated in the frame where the non-relativistic approximation is the best, the predicted results for these processes (including the helicity structures of D13 and F15) agree with the experimental data remarkably well. 相似文献
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9.
Atsushi Hosaka 《Nuclear Physics A》2001,680(1-4):167-170
10.
We analyse the properties of the ground state bayons in the non-relativistic quark model. The three-body problem is solved by means of the hyperspherical expansion. We consider various two-body potentials of power law type and also a three-body linear potential. In displaying the results, we insist on quantities like ratios of splittings which are scale independent and are functions only of the power of the potential and of the ratio of quark masses. 相似文献
11.
The constituent quark model is used to compute the ground and excited state masses of QQQ baryons containing either c or b quarks.The quark model parameters previously used to describe the properties of charmonium and bottomonium states were used in this analysis.The non-relativistic three-body bound state problem is solved by means of the Gaussian expansion method which provides sufficient accuracy and simplifies the subsequent evaluation of the matrix elements.Several low-lying states with quantum numbers J^P=1/2^±,3/2^±,5/2^±and 7/2^+are reported.We compare the results with those obtained by the other theoretical formalisms.There is a general agreement for the mass of the ground state in each sector of triply heavy baryons.However,the situation is more puzzling for the excited states,and appropriate comments about the most relevant features of our comparison are given. 相似文献
12.
D. Merten U. Löring B. Metsch H. Petry 《The European Physical Journal A - Hadrons and Nuclei》2003,18(2-3):193-195
Results on electromagnetic form factors of the nucleon and photon transition form factors of non-strange baryon resonances calculated in a relativistically covariant quark model based on the Bethe-Salpeter equation are presented. The relevance of the instanton-induced quark interaction on these properties is discussed.Received: 30 September 2002, Published online: 22 October 2003PACS:
11.10.St Bound and unstable states; Bethe-Salpeter equations - 12.39.Ki Relativistic quark model - 12.40.Yx Hadron mass models and calculations - 13.40.Gp Electromagnetic form factors 相似文献
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14.
S. Migura D. Merten B. Metsch H. -R. Petry 《The European Physical Journal A - Hadrons and Nuclei》2006,28(1):55-62
We calculate semileptonic decays of light and heavy baryons in a relativistically covariant constituent quark model. The model
is based on the Bethe-Salpeter equation in instantaneous approximation. It generates satisfactory mass spectra for mesons
and baryons up to the highest observable energies. Without introducing additional free parameters we compute on this basis
helicity amplitudes of electronic and muonic semileptonic decays of baryons. We thus obtain form factor ratios and decay rates
in good agreement with experiment. 相似文献
15.
The recent observation at the Tevatron of (uub and ddb) baryons within 2 MeV of the predicted Σb-Λb splitting and of baryons at the Tevatron within a few mega electron volts (MeV) of predictions has provided strong confirmation for a theoretical approach based on modeling the color hyperfine interaction. The prediction of = 5790-5800 MeV is reviewed and similar methods used to predict the masses of the excited states and . The main source of uncertainty is the method used to estimate the mass difference mb-mc from known hadrons. We verify that corrections due to the details of the interquark potential and to Ξb- mixing are small. For S-wave qqb states we predict , and . For states with one unit of orbital angular momentum between the b quark and the two light quarks we predict , and . Results are compared with those of other recent approaches. 相似文献
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18.
T. Van Cauteren J. Ryckebusch B. Metsch H. -R. Petry 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):613-615
We present some of our results for the electromagnetic properties of excited Σ hyperons, computed within the framework of the Bonn constituent-quark model, which is based on the Bethe-Salpeter approach.
The seven parameters entering the model are fitted against the best-known baryon masses. Accordingly, the results for the
form factors and helicity amplitudes are genuine predictions. We compare with the scarce experimental data available and discuss
the processes in which Σ
*'s may play an important role. 相似文献
19.
Mass spectra and semileptonic decay rates of baryons consisting of two heavy (b or c) and one light quark are calculated in the framework of the relativistic quark model. The doubly heavy baryons are treated in the quark-diquark approximation. The ground and excited states of both the diquark and quark-diquark bound systems are considered. The quark-diquark potential is constructed. The light quark is treated completely relativistically, while the expansion in the inverse heavy-quark mass is used. The weak transition amplitudes of heavy diquarks bb and bc going, respectively, to bc and cc are explicitly expressed through the overlap integrals of the diquark wave functions in the whole accessible kinematic range. The relativistic baryon wave functions of the quark-diquark bound system are used for the calculation of the decay matrix elements, the Isgur-Wise function, and decay rates in the heavy-quark limit. 相似文献
20.
Using a geometric model to study the structure of hadrons, baryons having one, two and three heavy quarks have been studied
here. The study reveals diquark structure in baryons with one and two heavy quarks but not with three heavy identical quarks. 相似文献