Showing papers on "Meson published in 1982"
TL;DR: In this article, the existence of states made of four heavy quarks in the context of potential models already used in the study of heavy mesons and baryons was discussed, where the quarks have the same mass and interact through a two-body potential due to color-octet exchange.
Abstract: We discuss the existence of states made of four heavy quarks in the context of potential models already used in the study of heavy mesons and baryons. We first consider the situation where the quarks have the same mass and interact through a two-body potential due to color-octet exchange. In this case, we show that for any reasonable confining potential there is no state below the threshold corresponding to the spontaneous dissociation into two mesons. We investigate in detail different possibilities of modifying this negative result. This concerns the effect of hyperfine corrections, the case of orbitally excited states, the case of unequal quark masses, and the use of the static potential derived from the bag model treated in the adiabatic approximation.
271 citations
TL;DR: In this paper, a model wave function was proposed to describe the strong or weak decays of heavy particles into two π(K)-mesons, which is based on the QCD sum rules.
242 citations
TL;DR: In this paper, the sum rules of mesons and baryons containing one heavy quark are calculated using the QCD sum rule method developed by Shifman, Vainshtein and Zakharov.
228 citations
TL;DR: In this paper, a relativistic interacting field theory of nucleons, hyperons, and mesons is studied in the context of neutron stars, and a large component of strange baryons is found.
141 citations
TL;DR: In this paper, two-loop corrections to the propagators of gluonic currents were calculated for finding the connection between the characteristic scales of quark and gluon worlds in perturbative QCD and for an estimate of the mass of the first radial excitation of the η′ meson.
134 citations
TL;DR: The most precise current value of the hyperfine Zeeman transitions in the ground state of muonium is obtained from the value of $\frac{{m}_{\ensuremath{\mu}}}{{m}_e}}$ is obtained.
Abstract: New higher precision measurements of the hyperfine Zeeman transitions in the ground state of muonium have been performed with use of the high-stopping-density surface ${\ensuremath{\mu}}^{+}$ beam at the Clinton P. Anderson Meson Physics Facility. The results are $\ensuremath{\Delta}\ensuremath{
u}=4463\ensuremath{-}302.88(16)$ kHz (0.036 ppm) and $\frac{{\ensuremath{\mu}}_{\ensuremath{\mu}}}{{\ensuremath{\mu}}_{p}}=3.1833461(11)$ (0.36 ppm). The current theoretical value of $\ensuremath{\Delta}\ensuremath{
u}$ agrees well with experiment within the 0.77-ppm error of $\ensuremath{\Delta}{\ensuremath{
u}}_{\mathrm{theor}}$, which is due principally to inaccuracy in evaluation of the nonrecoil radiative correction term. The most precise current value of $\frac{{m}_{\ensuremath{\mu}}}{{m}_{e}}$ is obtained from our value of $\frac{{\ensuremath{\mu}}_{\ensuremath{\mu}}}{{\ensuremath{\mu}}_{p}}$.
119 citations
TL;DR: In this article, the authors investigated the influence of the analytical continuation effects on the value of QCD scale parameter Λ extracted from the data on charmonium and upsilon hadron decays.
94 citations
TL;DR: In this paper, a high-resolution magnetic spectrograph was used to look for a discrete muon peak associated with heavy-neutrino emission in K/sub mu2/ decay.
Abstract: The muon momentum spectrum in K/sub mu2/ decay has been measured by using a high-resolution magnetic spectrograph to look for a discrete muon peak associated with heavy-neutrino emission. The spectrum revealed no distinct peak, and the upper bound of the mixing ratio between the muon neutrino and a massive neutrino has been determined to be 10/sup -4/--10/sup -6/ in the mass range of 70--300 MeV/c/sup 2/.
94 citations
TL;DR: Using the Borel transformed QCD sum rule formalism, the masses of L = 1 light quark mesons with isospin I = 1 and I = 0 were calculated in this paper.
88 citations
TL;DR: In this article, the authors analyzed a correlation function of two currents with quark exotic quantum numbers JPC = 1−+, IG = 0+ and 1−, following the technique of the ITEP group, and concluded that a strong peak should manifest itself in the spectral density of this correlation function at E ≈ 1 GeV.
78 citations
TL;DR: In this paper, the low-lying pseudoscalar and vector mesons containing u, d, s and c quarks are studied by the method of the hopping parameter expansion combined with a Monte Carlo simulation at 1g2 = 0.
TL;DR: In this paper, the authors present evidence for the production of two J/ψ mesons in the same interaction (13 events seen, for an expected background of about 0.2 events).
TL;DR: In this paper, the authors suggest that qqg mesons mat as low as 1 GeV in mass and that the exotic J PC = 1 −+ multiplet will have distinctive decay modes and perhaps be relatively stable.
TL;DR: In this article, it was shown that the whole quarkonium spectrum can be reproduced by a single nonrelativistic q − q potential V q q = V (scalar) + V (vector).
CERN1
TL;DR: The Drell-Yan process is an electromagnetic effect in which a quark and antiquark from a pair of interacting hadrons annihilate to give a lepton pair as mentioned in this paper.
Abstract: The Drell-Yan process is an electromagnetic effect in which a quark and antiquark from a pair of interacting hadrons annihilate to give a lepton pair. A brief description of hadron structure and the parton model is given to provide a necessary background. Then the general features of lepton pair production are described and the Drell-Yan formalism is set up. Experimental techniques are described next; these are rather simple since it is only necessary to detect the leptons emitted from hadron interactions. Predictions and tests of the basic model show that, in general, it works well. The anomalous features are the overall cross-section level (high by a factor of 2) and the unexpectedly large mean transverse momenta. Quantum chromodynamics (QCD) offers the explanation of these anomalies, and measurements of dilepton production provide important quantitative tests of QCD. Such measurements have also been used to determine nucleon structure functions and, for the first time, meson structure functions.
TL;DR: In this article, a relativistic quark-diquark model with a potential motivated by QCD was proposed, and the parameters of the model were determined by fitting vector-meson masses.
Abstract: Masses of ground-state spin-$\frac{3}{2}$ baryons are calculated in a relativistic quark-diquark model with a potential motivated by QCD. The parameters of the model are determined by fitting vector-meson masses, and so the calculation for baryons contains no free parameters. Results are in rather good agreement with experiment. Moreover, starting from dynamical quark masses close to the so-called current masses, effective quark masses are obtained in the right range to be identified with constituent masses.
CERN1
TL;DR: In this paper, a Monte Carlo computation of meson and hadron spectroscopy within lattice QCD is made, and the results are in agreement with the observed spectrum.
TL;DR: In this article, it was shown that the decay of heavy-flavoured mesons can be a source of neutral Higgs bosons, and it is shown that this decay can be used to detect the Higgs.
Abstract: It is shown that the decay of heavy-flavored mesons can be a source of neutral Higgs bosons.
TL;DR: In this article, a recent coincidence experiment d(e, e'p)n from Saclay is analyzed and the influences of final-state interactions, meson exchange currents and isobar configurations are studied.
TL;DR: In this article, the tensor mesons f, A2, A3 and A3 were analyzed within the frangework of QCD sum rules and the effects of gluon and quark condensates phenomenologically.
TL;DR: In this article, the mass spectrum and leptonic decay width of meson resonances in QCD were calculated on the basis of the use of finite-energy sum rules and the 1/N -expansion.
TL;DR: In this article, a natural explanation of the experimental D/sup +/ semileptonic branching ratio arises when mass and quantum-chromodynamic corrections are both taken into account.
Abstract: Mass effects in weak-decay rates of heavy particles are computed. A natural explanation of the experimental D/sup +/ semileptonic branching ratio arises when mass and quantum-chromodynamic corrections are both taken into account. The experimental results on semileptonic branching ratio of b-flavored B mesons allows the prediction of the lifetime ratio tau(B/sup -/)/tau(B-bar/sup 0/)< or =3.5 in a model-independent way.
TL;DR: In this article, a cross section for the production of mesons and particles in proton-proton interactions at the full phase space is presented, and a strong energy dependence of the production cross sections is observed.
Abstract: The inclusive cross section for the production ofK
0
mesons, Λ and
$$\bar \Lambda$$
particles in proton-proton interactions at
$$\sqrt s = 63$$
GeV is presented. The produced particles have been detected in the full phase space. Behaviour of the longitudinal and transversal depandences of the cross sections are discussed. The total production cross sections for
0
mesons and Λ particles was determined to
$$\sigma _{{\rm K}_S^0 } = (25.5 \pm 1.4)$$
mb andσ
Λ
=(7.8±1.2) mb respectively. A strong energy dependence of the production cross sections is observed.
TL;DR: In this paper, a relativistic mean field approach is used to determine and compare the single-particle Dirac potentials for nuclei and hypernuclei (Λ, Σ, Ξ).
TL;DR: The first measurements of the e+e− → KS0K±π∓ reaction in the 1.4-2.18 GeV energy range have been performed with the magnetic detector DM1 at the Orsay storage rings DCI as mentioned in this paper.
TL;DR: In this article, the structure observed in the reaction γγ → ϱ 0 ϱ ε 0 ϵ 0 is interpreted as due to 2 ++ (I = 0, 2) Q 2 Q 2Q 2 states with a background contribution from 0 ++ ( I = 0 and 2) q 2 Q 1 states.
TL;DR: In this paper, the decay patterns of q q g mesons were studied in the radiative decay of J/Ψ and it was shown that the 0++, 1++, 2++ states have typical hydronic decay widths and the decay modes are different from that of glueballs.
TL;DR: In this article, the model dependence of the spin parameters for low and medium energy antinucleon-nucleon (N-barN) scattering is discussed, and the sensitivity of these effects to changes in the real and imaginary parts of the N-BarN potential is explored.
Abstract: We discuss the model dependence of the spin parameters for low and medium energy antinucleon-nucleon (N-barN) scattering. An N-barN potential model is used, consisting of a t-channel meson exchange part, supplemented by a complex annihilation potential, adjusted to reproduce the observed energy dependence of total elastic, inelastic and charge exchange cross sections. A number of striking spin effects are predicted, particularly in the charge exchange channel. We explore the sensitivity of these effects to changes in the real and imaginary parts of the N-barN potential; in particular, we assess the possibility of extracting the strength of the coherent N-barN tensor potential due to ..pi.., rho, and ..omega.. exchange from future data. Some implications of our results for future experiments are mentioned.
TL;DR: In this article, the transverse mass spectra are well described by exp (−aμT), with a = −6.4±0.2 GeV−1.13 mb for φ.
TL;DR: In this article, the cross sections for π + and π − mesons were compared as a function of transverse momentum and it was shown that the inclusive cross section of mesons decreases faster than the π+ cross section.