共查询到20条相似文献,搜索用时 31 毫秒
1.
N. Fabiano 《The European Physical Journal C - Particles and Fields》1998,2(2):345-350
The possibility of formation for a bound state of a quark and a lighter one is investigated using potential model predictions and heavy quark effective theory approach. Resulting
estimates for the 1S–2S splitting of the energy levels are compared to the total top decay width . As for the case of toponium, our conclusions show that the probability of formation for T–mesons is negligibly small due
to the high top mass value.
Received: 2 April 1997 相似文献
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A brief review of the experimental situation concerning the electrically charged charmoniumlike meson candidates, Z-, is presented. 相似文献
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Bortoletto D Goldberg M Horwitz N Jain V Mestayer MD Moneti GC Sharma V Shipsey IP Skwarnicki T Thulasidas M Csorna SE Letson T Alexander J Artuso M Bebek C Berkelman K Cassel DG Cheu E Coffman DM Crawford G DeWire JW Drell PS Ehrlich R Galik RS Gittelman B Gray SW Halling AM Hartill DL Heltsley BK Kandaswamy J Katayama N Kreinick DL Lewis JD Mistry NB Mueller J Namjoshi R Nandi S Nordberg E O'Grady C Peterson D Pisharody M Riley D Sapper M Silverman A Stone S Worden H Worris M Sadoff AJ 《Physical review letters》1990,64(18):2117-2120
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Alexander Milov 《The European Physical Journal C - Particles and Fields》2009,61(4):721-728
This article reviews the current status of experimental results obtained in the measurement of light vector mesons produced
in proton-proton and heavy ion collisions at different energies. The review is focused on two phenomena related to the light
vector mesons; the modification of the spectral shape in search of chiral symmetry restoration and suppression of the meson
production in heavy ion collisions. The experimental results show that the spectral shape of light vector mesons are modified
compared to the parameters measured in vacuum. The nature and the magnitude of the modification depends on the energy density
of the media in which they are produced. The suppression patterns of light vector mesons are different from the measurements
of other mesons and baryons. The mechanisms responsible for the suppression of the mesons are not yet understood. Systematic
comparison of existing experimental results points to the missing data which may help to resolve the problem. 相似文献
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Strange axial-vector mesons 总被引:1,自引:0,他引:1
Suzuki M 《Physical review D: Particles and fields》1993,47(3):1252-1255
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Fulton R Jensen T Johnson DR Kagan H Kass R Morrow F Whitmore J Wilson P Bortoletto D Chen W Dominick J McIlwain RL Miller DH Ng CR Schaffner SF Shibata EI Shipsey IP Yao W Battle M Sparks K Thorndike EH Wang C Alam MS Kim IJ Li WC Romero V Sun CR Wang P Zoeller MM Goldberg M Haupt T Horwitz N Jain V Mestayer MD Moneti GC Rozen Y Rubin P Sharma V Skwarnicki T Thulasidas M Zhu G Csorna SE Letson T Alexander J Artuso M Bebek C Berkelman K Browder T Cassel DG Cheu E Coffman DM Crawford G DeWire JW 《Physical review D: Particles and fields》1991,43(3):651-663
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Almost thirty years ago, Penny G. Estabrooks asked “Where and what are the scalar mesons?” (P. Estabrooks, Phys. Rev. D 19, 2678 (1979)). The first part of her question can now be confidently responded (E. van Beveren et al., Z. Phys. C 30, 615 (1986)). However, with respect to the “What” many puzzles remain unanswered. Scalar and axial-vector mesons form part
of a large family of mesons. Consequently, though it is useful to pay them some extra attention, there is no point in discussing
them as isolated phenomena. The particularity of structures in the scattering of --basically-- pions and kaons with zero angular
momentum is the absence of the centrifugal barrier, which allows us to “see” strong interactions at short distances. Experimentally
observed differences and similarities between scalar and axial-vector mesons on the one hand, and other mesons on the other
hand, are very instructive for further studies. Nowadays, there exists an abundance of theoretical approaches towards the
mesonic spectrum, ranging from confinement models of all kinds, i.e., glueballs, and quark-antiquark, multiquark and hybrid configurations, to models in which only mesonic degrees of freedom
are taken into account. Nature seems to come out somewhere in the middle, neither preferring pure bound states, nor effective
meson-meson physics with only coupling constants and possibly form factors. As a matter of fact, apart from a few exceptions,
like pions and kaons, Nature does not allow us to study mesonic bound states of any kind, which is equivalent to saying that
such states do not really exist. Hence, instead of extrapolating from pions and kaons to the remainder of the meson family,
it is more democratic to consider pions and kaons mesonic resonances that happen to come out below the lowest threshold for
strong decay. Nevertheless, confinement is an important ingredient for understanding the many regularities observed in mesonic
spectra. Therefore, excluding quark degrees of freedom is also not the most obvious way of describing mesons in general, and
scalars and axial-vectors in particular. 相似文献
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J. M. Richard 《Physics letters. [Part B]》1981,100(6):515-518
We discuss the possibility of extrapolating the phenomenology of the meson spectrum in potential models to the rich domain of the baryons. As an illustration, we have computed the mass of the Ω− using a recent empirical quark-antiquark potential. 相似文献
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G. Y. Wolf 《Pramana》2006,66(4):781-790
One consequence of the chiral restoration is the mixing of parity partners. We look for a possible signature of the mixing
of vector and axial vector mesons in heavyion collisions. We suggest an experimental method for its observation. The dynamical
evolution of the heavy-ion collision is described by a transport equation of QMD-type evolving nucleons,N* and Δ resonances, Λ’s and gS baryons, and furthermore,π’s,η’sρ’sσ’sΩ’s and kaons with their isospin degrees of freedom. The input cross-sections and resonance parameters of the model are fitted
to the available nucleon-nucleon and pion-nucleon cross-sections 相似文献
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E. Kyriakopoulos 《International Journal of Theoretical Physics》1973,8(4):283-297
A model containing a nonet of scalar mesonsS, a nonet of pseudoscalar mesonsP, and a nonet of baryons is constructed where the mesons enter in the form of the matrixM=ei(S+iP), Several Lagrangians are introduced such that the mesons get their physical masses, and the decay widths of the scalar mesons are calculated. The model satisfies generalized PCAC. It is found that the coupling constants of the mesonsε(700) andε′(1060) to pions and nucleons satisfy the relations: $$\frac{{|G_{\varepsilon NN} |}}{{|G_{\varepsilon \pi \pi } |}} = 1 \cdot 4,\frac{{|G_{\varepsilon 'NN} |}}{{|G_{\varepsilon '\pi \pi } |}} = 0 \cdot 89,\frac{{|G_{\varepsilon \pi \pi } G_{\varepsilon NN} |}}{{4\pi }} = 4 \cdot 9,{\text{and}}\frac{{|G_{\varepsilon '\pi \pi } G_{\varepsilon 'NN} |}}{{4\pi }} = 0 \cdot 34.$$ 相似文献
19.
P. Burcev 《International Journal of Theoretical Physics》1988,27(6):673-675
An energy eigenstates equation for mesons is derived and the energy levels of strange mesons are calculated and compared with those observed. For equal quark masses (m
u
=m
d
) the mass formula reduces to the mass formula describing nonflavored mesons withI=1. 相似文献
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Adams GS Anderson M Cummings JP Danko I Hu D Moziak B Napolitano J He Q Insler J Muramatsu H Park CS Thorndike EH Yang F Artuso M Blusk S Khalil S Li J Menaa N Mountain R Nisar S Randrianarivony K Sia R Skwarnicki T Stone S Wang JC Bonvicini G Cinabro D Dubrovin M Lincoln A Asner DM Edwards KW Naik P Briere RA Ferguson T Tatishvili G Vogel H Watkins ME Rosner JL Adam NE Alexander JP Cassel DG Duboscq JE Ehrlich R Fields L Gibbons L Gray R Gray SW Hartill DL Heltsley BK Hertz D Jones CD 《Physical review letters》2007,99(19):191805
Using data collected near the D{s}{*+}D{s}{-} peak production energy E_{cm}=4170 MeV by the CLEO-c detector, we study the decays of D{s}{+} mesons to two pseudoscalar mesons. We report on searches for the singly Cabibbo-suppressed D{s}{+} decay modes K{+}eta, K{+}eta', pi{+}K{S}{0}, K{+}pi{0}, and the isospin-forbidden decay mode D{s}{+}-->pi{+}pi{0}. We normalize with respect to the Cabibbo-favored D{s}{+} modes pi{+}eta, pi{+}eta', and K{+}K{S}{0}, and obtain ratios of branching fractions: B(D{s}{+}-->K{+}eta)/B(D{s}{+}-->pi{+}eta)=(8.9+/-1.5+/-0.4)%, B(D{s}{+}-->K{+}eta')/B(D{s}{+}-->pi{+}eta')=(4.2+/-1.3+/-0.3)%, B(D{s}{+}-->pi{+}K{S}{0})/B(D{s}{+}-->K{+}K{S}{0})=(8.2+/-0.9+/-0.2)%, B(D{s}{+}-->K{+}pi{0})/B(D{s}{+}-->K{+}K{S}{0})=(5.5+/-1.3+/-0.7)%, and B(D{s}{+}-->pi{+}pi{0})/B(D{s}{+}-->K{+}K{S}{0})<4.1% at 90% C.L., where the uncertainties are statistical and systematic, respectively. 相似文献