共查询到20条相似文献,搜索用时 15 毫秒
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Results obtained by studying the properties of the leading-twist wave functions for the S- and P-wave states of charmonia are presented. Wave-function models that can be used to calculate various processes involving the
production of these mesons were constructed on the basis of these investigations. Calculations for some exclusive processes
of charmonium production were performed within the models in question. 相似文献
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Masses of low-lying hybrid states in the spectrum of charmonium are calculated in the framework of the Vacuum Correlators
Method. Predictions are compared with the lattice simulations as well as with the recent experimental data.
The text was submitted by the authors in English. 相似文献
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Benedikt Humpert 《Physics letters. [Part B]》1977,68(1):66-70
Photoproduction of ortho and para charm-anticharm bound states is considered in the framework of the Cheng-Wu picture. Non-Abelian gauge gluons mediate the interaction between the c-pair and the nucleon. The angular distributions of ψc and ηc are determined. The influence of multigluon exchanges and quark mass variation is studied. 相似文献
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M.Nielsen 《中国物理C(英文版)》2010,34(9)
In the last years many states in the charmonium mass region were discovery by BABAR, Belle and CDF collaborations. I discuss some of these discoveries, and how the QCD Sum Rule approach can be used to understand the structure of these states. 相似文献
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M. Nielsen 《中国物理 C》2010,34(9):1157-1162
In the last years many states in the charmonium mass region were discovery by BABAR,Belle and CDF collaborations.I discuss some of these discoveries,and how the QCD Sum Rule approach can be used to understand the structure of these states. 相似文献
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Within the NRQCD factorization approach the production of heavy quarkonia can be calculated in perturbative QCD in terms
of a few production-process-independent NRQCD matrix elements. We test the universality of these long-distance matrix elements
by comparing their values as determined from charmonium production at , ep, and colliders, and in , , and B decays.
Received: 27 April 1998 / Published online: 22 March 1999 相似文献
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We take the recently found charmonium state at 2.976 GeV to be the η c and show that it can be included in a charmonium model with relativistic corrections which reproduces the s-wave spectrum, the leptonic widths Γ(V→e + e?) and the p-wave splittings. The upsilon spectrum is discussed as are the effects of radial and pseudoscalar mixing. 相似文献
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In this work a formula for charmonium suppression obtained by Matsui in 1989 is analytically generalized for the case of complex $c\bar c$ potential described by a 3-dimensional and isotropic time-dependent harmonic oscillator (THO). It is suggested that under certain scheme the formula can be applied to describe J/?? suppression in heavy-ion collisions at CERN-SPS, RHIC, and LHC with the advantage of analytical tractability. 相似文献
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The dimensiond=4 gluon condensateφ 1 is determined from an analysis of charmonium, taking model dependent estimates ofd=6.8 condensates into account. ForS-waves, there is a compatibility region, where both these and model dependent higher state corrections to ground state dominance are small, enablingφ 1 to be determined from a fit to the data. ForP-waves the estimated higher dimension contributions are large in the region of ground state dominance, and noφ 1 determination is possible. Theφ 1 value obtained from the fit to theS-wave ratios is 3 5 times bigger than that obtained by RRY using the plateau method. The methods are compared for the vector current. We show that the higher state correction used by RRY does not fit the data; and that the plateau method is much more sensitive to thed=6.8 condensates than the ratio used here. When reasonable estimates of both these and the higher state corrections are taken into account, there is compatibility between the two methods. 相似文献
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The mass spectra of charmonium are investigated using a Coulomb plus linear(Cornell)potential.Gaussian wave functions in position space as well as in momentum space are employed to calculate the expectation values of potential and kinetic energy respectively.Various experimental states(X(4660)(5~3S_1),X(3872)(2~3P_1),X(3900)(2~1P_1),X(3915)(2~3P_0)and X(4274)(3~3P_1)etc.)are assigned as charmonium states.We also study the Regge trajectories,pseudoscalar and vector decay constants,electric and magnetic dipole transition rates,and annihilation decay widths for charmonium states. 相似文献
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We discuss the shape of threshold signals in production cross sections of the reaction e<'+>e<,-> → D<'*>D<'*>, at the opening of the D<,s><'*>D<,s><'*> and Λ<,c><'+>Λ<,c><'-> channels. Furthermore, evidence for the ψ(3D), ψ(5S), ψ(4D), ψ(6S), ψ(5D), ψ(7S), ψ(6D), and ψ(8S) new charmonium vector resonances is presented, on the basis of data recently published by the BABAR Collaboration. Central masses and resonance widths are estimated. Confirmation of these resonances would be a huge step in lifting the precision level of hadron spectroscopy towards that of atomic spectroscopy, with far-reaching consequences for theory. 相似文献
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We discuss the shape of threshold signals in production cross sections of the reaction e+e-→ D*D*, at the opening of the Ds*Ds* and Λc+Λc- channels. Furthermore, evidence for the ψ(3D), ψ(5S), ψ(4D), ψ(6S), ψ(5D), ψ(7S), ψ(6D), and ψ(8S) new charmonium vector resonances is presented, on the basis of data recently published by the BABAR Collaboration. Central masses and resonance widths are estimated. Confirmation of these resonances would be a huge step in lifting the precision level of hadron spectroscopy towards that of atomic spectroscopy, with far-reaching consequences for theory. 相似文献
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We suggest the variation of charmonium production rate with Feynman x(F) in heavy ion collisions as a novel and sensitive probe for the properties of the created matter. Final state interactions with the comoving matter create a minimum at x(F) = 0, which is especially deep and narrow if a quark-gluon plasma is formed. While a strong effect is predicted at SPS, at the RHIC energy it overlaps with the expected peak formed by shadowing effects and needs comparison with pA data. We predict a steep dependence on centrality and suggest that this new probe is complementary to the dependence on transverse energy, and is more sensitive to a scenario of final state interactions. 相似文献
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J. Weiss 《Czechoslovak Journal of Physics》1995,45(9):689-698
It is shown that the relativistic linear potentials, introduced by the author within the particle à la Wheeler-Feynman direct-interaction (AAD) theory, applied to the semiclassically quantized charmonium, yield energy spectrum comparable to that of some known models. Using the expansion of the relativistic linear AAD potentials in powers ofc
–1, the charmonium spectrum, given as a rule by Bohr-Sommerfeld quantization of circular orbits, is extended up to the second order of relativistic corrections. 相似文献