Showing papers on "Meson published in 1979"
TL;DR: In this article, the existing results concerning mesons and glue states in the large-N limit of QCD are reviewed, and it is shown how to fit baryons into this picture.
1,934 citations
TL;DR: In this article, the eigenvalues of the evolution equations appear as exponents in anomalous logarithm corrections to the nominal power law of form factors determined by dimensional counting.
892 citations
TL;DR: In this article, the authors apply the methodology of the operator product expansion to a number of processes involving the coupling of heavy quark-anti-quark mesons to light hadrons.
282 citations
TL;DR: In this article, the invariant cross-sections of hadrons at large transverse momentum were measured at a laboratory angle of 77 mrad, which corresponds to angles near 90\ifmmode^\circ\else\textdegree\fi{} in the c.m. system of the incident proton and a single nucleon at rest.
Abstract: Measurements of the invariant cross section $\frac{E{d}^{3}\ensuremath{\sigma}}{{d}^{3}p}$ are presented for the production of hadrons ($\ensuremath{\pi}$, $K$, $p$, and $\overline{p}$) at large transverse momentum (${p}_{\ensuremath{\perp}}$) by 200-, 300-, and 400-GeV protons incident on ${\mathrm{H}}_{2}$, ${\mathrm{D}}_{2}$, Be, Ti, and W targets. The measurements were made at a laboratory angle of 77 mrad, which corresponds to angles near 90\ifmmode^\circ\else\textdegree\fi{} in the c.m. system of the incident proton and a single nucleon at rest. The range in ${p}_{\ensuremath{\perp}}$ for the data is $0.77\ensuremath{\le}{p}_{\ensuremath{\perp}}\ensuremath{\le}6.91$ GeV/c, corresponding to values of the scaling variable ${x}_{\ensuremath{\perp}}=\frac{2{p}_{\ensuremath{\perp}}}{\sqrt{s}}$ from 0.06 to 0.64. For $p\ensuremath{-}p$ collisions, the pion cross sections can be represented in the region ${x}_{\ensuremath{\perp}}g35$ by the form $(\frac{1}{{{p}_{\ensuremath{\perp}}}^{n}}){(1\ensuremath{-}{x}_{\ensuremath{\perp}})}^{b}$, with $n=8$ and $b=9$. The ratio of ${\ensuremath{\pi}}^{+}$ to ${\ensuremath{\pi}}^{\ensuremath{-}}$ production grows as a function of ${x}_{\ensuremath{\perp}}$ to a value larger than 2 at ${x}_{\ensuremath{\perp}}\ensuremath{\gtrsim}0.5$. The ratios of the production of ${K}^{+}$ and protons to ${\ensuremath{\pi}}^{+}$ and of ${K}^{\ensuremath{-}}$ and antiprotons to ${\ensuremath{\pi}}^{\ensuremath{-}}$ also scale with ${x}_{\ensuremath{\perp}}$ for $p\ensuremath{-}p$ collisions. The ${K}^{\ifmmode\pm\else\textpm\fi{}}$, $p$, and $\overline{p}$ fitted values for $n$ and $b$ are given. Particle ratios are also presented for ${\mathrm{D}}_{2}$, Be, Ti, and W targets and the dependences on atomic weight ($A$) are discussed.
254 citations
TL;DR: In this paper, the authors studied the asymmetry in the decay of heavy charged mesons into a definite final state as compared with the charge-conjugated mode and found that measurable asymmetries may arise.
Abstract: Within the context of a six-quark model combined with quantum chromodynamics we study the asymmetry in the decay of heavy charged mesons into a definite final state as compared with the charge-conjugated mode. We find that, in decays of mesons involving the $b$ quark, measurable asymmetries may arise. This would present the first evidence for $\mathrm{CP}$ noninvariance in charged systems.
228 citations
TL;DR: In this article, the SU/sub c/(3) x SU(2) x U(1) model without generating anomalies is shown to have Cabibbo universality.
Abstract: The formula tan/sup 2/theta/sub C/ approx. = m/sub d//m/sub s/ is derived from a continuous symmetry. Cabibbo universality is guaranteed in a natural way. All weak mixing angles are determined in terms of quark masses. The b quark is predicted to decay mainly to the u quark, and the lifetime of the associated mesons is approx. 10/sup -10/ - 10/sup -11/ sec. We argue that this additional symmetry is (essentially) the only one which can be added to the standard SU/sub c/(3) x SU(2) x U(1) model without generating anomalies.
209 citations
TL;DR: In this paper, it was shown that the true Higgs mesons do not mediate flavor changing interactions and that the masses of the spinless mesons can be arbitrarily large without affecting the structure of the weak interactions.
203 citations
TL;DR: In this article, the authors proposed a new method of analyzing low-energy hadron-hadron scattering designed to reveal internal quark-gluon eigenstates, which is a modification of the Wigner-Eisenbud formalism suited to the case of confining boundary conditions.
Abstract: We propose a new method of analyzing low-energy hadron-hadron scattering designed to reveal internal quark-gluon eigenstates. Our method is a modification of the Wigner-Eisenbud formalism suited to the case of confining boundary conditions. We have identified a matrix function of the energy (which we call $P$) whose poles and residues correspond to the masses and channel projections of quark-gluon eigenstates calculated with spherical bag boundary conditions. To illustrate the formalism we apply it to the low-energy $S$-wave scattering of pseudoscalar mesons. We find from the data clear evidence of internal states corresponding to quark-model predictions of ${Q}^{2}{\overline{Q}}^{2}$ states at 0.69 and 1.04 GeV in the $I=0$ channel, at 0.96 GeV in the $I=\frac{1}{2}$ channel, at 1.19 GeV in the $I=\frac{3}{2}$ channel, and at 1.04 GeV in the $I=2$ channel. We believe the $I=\frac{3}{2} \mathrm{and} 2$ internal states to be the low-energy exotics long predicted by quark models.
170 citations
Book•
01 Jun 1979
TL;DR: In this paper, Schur's Lemma and Orthogonality Relations are used for partial wave and fermion problems. But they do not specify the relationship between the two functions.
Abstract: 1 One-Particle Problems.- 2 Two-Particle Problems.- 3 Radiation and Quantum Electrodynamics.- 4 The Particle Zoo.- 5 Weak Interactions.- 6 Analyticity and Strong Interactions.- 7 Particular Hadronic Processes.- 8 Particular Electromagnetic Processes in Collisions with Atoms and Nuclei.- Appendices.- A Some Formulas for Partial Waves and Fermions.- A-1 Spherical Bessel, Neuman and Hankel Functions.- A-2 Coulomb Wave Functions.- A-3 Reduction of Dirac Matrices.- A-4 Fermion Spin Summation.- B-1 Unitary Matrices and Their Representations.- B-2 Schur's Lemma and Orthogonality Relations.- B-4 Calculation of the d-Functions.- C Units and Particle Tables.- C-1 Units and Fundamental Constants and Table of Leptons.- C-2 The Pseudoscalar Mesons.- C-3 The Vector Mesons.- C-4 The Baryon Octet.- C-5 The Baryon Decuplet.- C-6 The Tensor Mesons.- C-7 The New Bosons.- References.
152 citations
TL;DR: In this article, a quantitative understanding of mirror Gamow-Teller transition in the nuclei was provided, considering core polarization, meson exchange, and relativistic corrections.
Abstract: Consideration of core polarization, meson exchange, and relativistic corrections gives a satisfactory, quantitative understanding of mirror Gamow-Teller $\ensuremath{\beta}$-transitions in $A=3, 15, 17, 39, \mathrm{and} 41$ nuclei.
TL;DR: In this article, the relativistic quantum field theory of Walecka is extended to include the interactions of π and ρ mesons, and a non-abelian gauge theory is derived and applied to calculations of cold nuclear matter.
TL;DR: In this paper, a complete set of rotationally invariant observables (Hl) is presented to characterize the shape of the final states in e+e− annihilation processes.
TL;DR: In this paper, a consistent nonrelativistic treatment of deuteron electrodisintegration including effects from meson exchange currents and isobar configurations is presented and the T-matrix is calculated by a multipole expansion up to L = 6 for inclusion of the final state interaction.
TL;DR: In this paper, the strong interaction coupling constants of the S ∗ and δ mesons with the K K channel were determined to be of the order of [(m K 0 − m K + )/m K − 0 ] 1 2, and not of (mK0 − mK+)/mK 0, as would be expected from simple considerations.
TL;DR: In this paper, the sum rules induced by the current G μν a Ḡ μν A constructed from gluon field operators are derived and the difference between the η′ and typical quark states such as ϱ is noted.
TL;DR: In this article, the weak one-pion production mechanism is analyzed in terms of resonant and non-resonant contributions coming from the πN invariant-mass region extended from threshold to 1.6 GeV/ c 2.
TL;DR: In this article, a semiclassical model is presented for the way the energy of a fast quark is transformed into observable hadrons, which reproduces the features of 1+1 dimensional QED (the Schwinger model) concerning a flat rapidity distribution in the central region.
Abstract: A semiclassical model is presented for the way the energy of a fast quark is transformed into observable hadrons. It reproduces the features of 1+1 dimensional QED (the Schwinger model) concerning a flat rapidity distribution in the central region. It also reproduces results from phenomenological considerations, which, based upon scaling, predict that meson formation in the fragmentation region can be described by an iterative scheme, implying a set of coupled integral equations. In particular the model predicts that the probability to find a meson containing the leading quark is independent of the Feynman scaling variablez. The iterative structure corresponds to a Brownian motion with relevance both to the confinement problems and to the distribution of mass in the quark jet.
TL;DR: In this article, the γ-spectra induced by stopped K− mesons in 6Li and 7Li targets in coincidence with the accompanying charged pions and π0 mesons was identified as a γ transition in Λ4H, whereas the π-line at (1.15 ± 0.04)_MeV observed with π 0 mesons is ascribed to a −δ-transition in γ4He.
TL;DR: In this paper, a generalized Cabibbo fit and constraints on the predicted values of the K/sub L/-K/sub S/ mass difference and CP-nonconservation parameter epsilon were used to determine optimal bounds on the quark mixing angles in the Weinberg-Salam model.
Abstract: Using existing data we determine optimal bounds on the quark mixing angles in the standard six-quark Kobayashi-Maskawa version of the Weinberg-Salam model. The analysis is based on a recent generalized Cabibbo fit and constraints on the predicted values of the K/sub L/-K/sub S/ mass difference and CP-nonconservation parameter epsilon. We give resulting bounds on branching ratios and lifetimes of c-, b-, and t-flavored hadrons.
TL;DR: In this paper, the dependence of the Pomeron term on the momentum transfer is taken from a modified version of the relation between matter distribution and charge distribution, and a simple nontrivial form is used for the hadronic-matter current in the proton.
Abstract: We improve significantly the impact picture that was used several years ago to predict the increase of total and integrated differential cross sections at high energies. The major improvements consist of the following: (1) The dependence of the Pomeron term on the momentum transfer is taken from a modified version of the relation between matter distribution and charge distribution, (2) Regge backgrounds are properly taken into account, and (3) a simple nontrivial form is used for the hadronic-matter current in the proton. For proton-proton elastic scattering, the phenomenological differential cross section is in good agreement with the experimental data in the laboratory momentum range of 14 to 2000 GeV/c, and is predicted for ISABELLE energy. Because of the third improvement, predictions are obtained for both polarization and $R$ parameters for proton-proton elastic scattering.
TL;DR: In this article, the Kobayashi-Maskawa weak current model was used to investigate the properties of weak hadronic decays of the bottom mesons of the predicted bottom meson.
Abstract: Based on the Kobayashi-Maskawa weak current model we investigate the properties of weak hadronic decays of the anticipated bottom mesons. Our main results concern twobody and quasitwobody decays of bottom mesons into pseudoscalar and vector mesons.
TL;DR: In this paper, the authors examined the magnitude of the cosmological baryon asymmetry arising in several of the standard models of CP violation, including the Kobayashi-Maskawa model.
Abstract: We have examined the magnitude of the cosmological baryon asymmetry arising in several of the standard models of CP violation. Agreement with the experimental baryon to photon number ratio n/sub B//n/sub ..gamma../ approx. = 10/sup -8/ is obtained in models where superheavy Higgs mesons decay with complex amplitude into other Higgs mesons. By contrast, in the Kobayashi-Maskawa model n/sub B//n/sub ..gamma../ approx. = O (10/sup -20/).
TL;DR: In this paper, it was shown that an increase of the density of cold matter leads to the condensation of W mesons, and that the densities of all types of right and left leptons (baryons) in superdense matter become equal to each other.
TL;DR: In this article, the authors compare and contrast several theoretical approaches which could account for a new class of narrow mesons recently observed in the mass region 1.5 − 3 GeV/c2, particularly those clustered near the antinucleon-nucleon (N N ) threshold.
TL;DR: In this article, the momentum distribution of valence quarks in the pion has been determined based on data on muon-pair production by pions and the shape of a nucleon structure function has been obtained.
Abstract: Data on muon-pair production by pions are used to determine the momentum distribution for valence quarks in the pion. The shape of a nucleon structure function is also obtained and is compared with a calculation based on existing data.
TL;DR: In this article, evidence for the forward production of D + mesons has been found in pp collisions at a c.m. energy of 52.5 GeV and a signal of 92 ± 18 events above background has been observed in the decay channel.
TL;DR: In this paper, the authors discuss corrections from unitarity and analyticity to the meson masses and mixing angles corresponding to the lowest q q states of the quark model.