Showing papers on "Elementary particle published in 1985"
TL;DR: It is suggested that the $\ensuremath{\rho}$ meson is a dynamical gauge boson of a hidden local symmetry in the non-linear chiral Lagrangian.
Abstract: We suggest that the $\ensuremath{\rho}$ meson is a dynamical gauge boson of a hidden local symmetry in the non-linear chiral Lagrangian. The origin of the $\ensuremath{\rho}$-meson mass is understood as the Higgs mechanism of the hidden local symmetry. The low-energy dynamics of $\ensuremath{\rho}$, $\ensuremath{\pi}$, and matter fields, including the Kawarabayashi-Suzuki-Riazuddin-Fayyazuddin relation and $\ensuremath{\rho}$-coupling universality, is consistently described in this new framework. The electromagnetic interaction can be introduced in a unique manner, which gives a successful explanation of $\ensuremath{\rho}$ dominance of the photon coupling.
632 citations
TL;DR: In this article, the chiral Schwinger model is shown to yield a consistent and unitary, although not gauge-invariant, theory, which is exactly solvable and contains a free massive vector boson plus harmonic excitations.
Abstract: We show that the chiral Schwinger model, which is anomalous, yields a consistent and unitary, although not gauge-invariant, theory. The model is exactly solvable and contains a free massive vector boson plus harmonic excitations.
396 citations
TL;DR: Elementary cross sections for the production of supersymmetric partners of the known constituents and gauge bosons in collisions of quarks and gluons are calculated in tree approximation using standard renormalization-group-improved parton-model methods.
Abstract: Elementary cross sections for the production of supersymmetric partners of the known constituents and gauge bosons in collisions of quarks and gluons are calculated in tree approximation. Standard renormalization-group-improved parton-model methods are then used to estimate differential and integrated production cross sections in proton-proton and proton-antiproton collisions. For completeness, some analogous results are presented for electron-positron collisions. Decay modes, experimental signatures, and bounds on masses of supersymmetric partners are surveyed, and prospects for future searches are discussed.
266 citations
TL;DR: In this paper, the parity nonconservation in the standard model of elementary particles and in nuclear physics is studied. Meson-nucleon couplings are discussed and A = 18 nuclei are considered in detail.
Abstract: Parity nonconservation is studied in the standard model of elementary particles and in nuclear physics. Meson--nucleon couplings are discussed and A = 18 nuclei are considered in detail. Analyzing power measurements are reviewed. (AIP)
185 citations
TL;DR: In this paper, a solar neutrino problem is considered and the present abundance of neutrinos is determined by balancing capture rates against annihilation rates in the Sun, based on a combination of particle physics and cosmological considerations.
Abstract: Certain currently proposed weakly interacting elementary particles can have a high probability of solar capture if they make up the Galactic halo. Their present abundance in the Sun is here determined by balancing capture rates against annihilation rates. Both particle physics and cosmological considerations impose constraints on scattering and annihilation cross sections. In general, for the candidate particles here discussed (massive neutrinos, supersymmetric scalar neutrinos, and photinos), the inferred solar abundances are too small by three to four orders of magnitude to solve the solar neutrino problem. Extreme fine tuning, marginally possible in the case of the photino, could increase solar abundances to a level where the neutrino signature would be affected. Otherwise, either a particle with a net cosmological asymmetry, or else a new mechanism for strengthening the existing Majorana suppression of s-wave annihilation at very low energies, would seem to be required.
142 citations
TL;DR: In this article, the solar evolutionary consequences of both imposed isothermal core models and models including energy transport by a specific class of weakly interacting particles were explored, and a relative mass fraction, 10/sup -8/, of 4GeV particles was shown to reduce predicted neutrino count rates by more than a factor of 3.
Abstract: If the Sun contained even a small mass fraction of weakly interacting massive particles, there could be significant effects on central solar structure. The long mean free paths associated with such particles make them very efficient energy conductors. Consequently, an essentially isothermal core can be produced, which removes the central temperature peak responsible for the bulk of the predicted solar neutrinos in Davis's /sup 37/Cl neutrino capture experiment. We explore the solar evolutionary consequences of both imposed isothermal core models and models including energy transport by a specific class of weakly interacting particles. In particular, a relative mass fraction, 10/sup -8/, of 4GeV particles reduces predicted neutrino count rates by more than a factor of 3.
118 citations
TL;DR: In this paper, the authors examined the value of the Higgs mass in models with two Higgs doublets and spontaneous CP violation, and showed that in the presence of a softly broken permutation symmetry, the mass can be lower than one TeV without having to resort to unnatural fine-tuning of parameters.
114 citations
TL;DR: In this article, the authors investigated the hypothesis that at least one of the known neutrinos travels faster than light and the current experimental situation is examined within this purview within this conjecture.
111 citations
TL;DR: In this paper, the couplings in the standard model with one Higgs doublet and n generations were reduced to about 10-15% and the error was estimated to be about 10−15%.
98 citations
TL;DR: In this article, the maximum lifetimes of neutrinos with masses more than a few MeV were derived, ranging from a few thousand seconds upward, depending on the particle mass, and approximate expressions for other particles, with different masses and abundances, such as gravitinos.
Abstract: Particles with masses more than a few MeV, decaying into photons or electrons, can cause destruction by photofission of cosmologically produced light elements. A previous calculation of this effect is corrected and extended, and used to derive maximum lifetimes for massive neutrinos; these range from a few thousand seconds upward, depending on the particle mass. Some approximate expressions are given that enable lifetime limits to be obtained for other particles, with different masses and abundances, such as gravitinos. These limits are generally stronger than previously determined constraints, such as distortion of the microwave background by energetic photons.
96 citations
TL;DR: The meson spectrum in a model with a confining Lorentz-vector is studied and it is found that the pion satisfies the expected dispersion law for a Goldstone boson, f/sub piprime/ = 0 in the chiral limit, where ..pi..' is any radially excited pion.
Abstract: We study the meson spectrum in a model with a confining Lorentz-vector: and hence chiral-invariant: interaction between massless quark fields. As shown in a previous work, chiral invariance is spontaneously broken. In the case of the harmonic oscillator, as the Fourier transform of the potential is the Laplacian of a delta function, the Bethe-Salpeter (BS) equation: a system of linear integral equations in general: splits into a system of differential equations that we solve in the broken vacuum. Without appealing to any spin-spin interaction, we find, besides the massless pseudoscalar, a vector meson at the right scale and an excited pion and two vectors in the 1--2-GeV region. Moreover, we find a large L-S splitting with the expected ordering for a vector interaction. We study in detail the BS wave function for the pion in motion, necessary to compute axial-vector-current matrix elements, and recover well known relations of current algebra. We compute f/sub ..pi../ and find on general grounds that f/sub piprime/ = 0 in the chiral limit, where ..pi..' is any radially excited pion. The pion satisfies the expected dispersion law for a Goldstone boson, ..omega..(p)..-->..cp (p..-->..0). .AE
TL;DR: In this paper, a model for the fragmentation of heavy quarks is proposed, based on a scheme used previously to calculate hadron structure functions, which embodies the hardness expected from the decay kinematics, and is consistent with'reciprocity', which demands that the fragmentation function should be related to the hadronic structure function.
Abstract: A model for the fragmentation of heavy quarks is proposed, based on a scheme used previously to calculate hadron structure functions. It embodies the hardness expected from the decay kinematics, and is consistent with 'reciprocity', which demands that the fragmentation function should be related to the hadronic structure function. It agrees with the data on c and b quark fragmentation, but its predictions for t and other very heavy quarks are significantly different from the model of Peterson et al., (1983), for example.
TL;DR: In this article, the one-loop electroweak radiative corrections to the longitudinal polarization asymmetry and forward-backward asymmetry were calculated on and off Z 0 resonance in a renormalization scheme which uses τ e.m. (0), M Z, H H, M fermions and μ μ (the muon decay lifetime) as input data.
TL;DR: The possibility of the production of a new neutral elementary particle in heavy-ion collisions is discussed in this article, where the authors consider the possibility of creating a new particle in the presence of heavy ion collisions.
Abstract: The possibility of the production of a new neutral elementary particle in heavy-ion collisions is discussed.
TL;DR: In this paper, results are presented from a study of the hadronic final states in e/sup +/e/sup -/ annihilation at 29 GeV, obtained with the High Resolution Spectrometer at the SLAC PEP e/Sup -/ colliding-beam facility.
Abstract: In this paper, results are presented from a study of the hadronic final states in e/sup +/e/sup -/ annihilation at 29 GeV. The data were obtained with the High Resolution Spectrometer (HRS) at the SLAC PEP e/sup +/e/sup -/ colliding-beam facility. The results are based on 6342 selected events corresponding to an integrated luminosity of 19.6 pb/sup -1/. The distributions of the events in sphericity (S), thrust (T), and aplanarity (A) are given and compared to other e/sup +/e/sup -/ data in the same energy range. We measure = 0.130 +- 0.003 +- 0.010 and = 0.100 +- 0.002. The sphericity distribution is compared to sphericity measurements made for beam jets in hadronic collisions as well as jets studied in neutrino scattering. The data sample is further reduced to 4371 events with the two-jet selections, S< or =0.25 and A< or =0.1. The single-particle distributions in the longitudinal and transverse directions are given. For low values of the momentum fraction (z = 2p/W), the invariant distribution shows a maximum at zapprox.0.06, consistent with a QCD expectation. The data at high Feynman x (x/sub F/) show distribution consistent with being dominated by a (1-x/sub f/)/sup 2/ variation for themore » leading quark-meson transition. The rapidity distribution shows a shallow central minimum with a height (1/N/sub e//sub v/dN/sup h//dYVertical Bar= 0 = 2.3 +- 0.02 +- 0.07.« less Authors: Bender, D. ; Derrick, M. ; Fernandez, E. ; Fries, R. ; Gieraltowski, G. ; Hyman, L. ; Jaeger, K. ; Klem, R. ; Kooijman, P. ; Loos, J.S. ; LoPinto, F. ; Musgrave, B. ; Price, L.E. ; Schlereth, J. ; Schreiner, P. ; Singer, R. ; Sugano, K. ; Trinko, T. ; Valdata-Nappi, M. ; Ward, C. more »; Weiss, J.M. ; Ahlen, S. ; Baranko, G. ; Baringer, P. ; Blockus, D. ; Brabson, B. ; Daigo, M. ; Ems, S. ; Forden, G.E. ; Gray, S.W. ; Guillaud, J. ; Jung, C. ; Neal, H. ; Ogren, H. ; Rust, D. ; Smith, P. ; Akerlof, C. ; Chapman, J. ; Errede, D. ; Harnew, N. ; Kesten, P. ; Kooijman, S. ; Meyer, D.I. ; Nitz, D. ; Rubin, D. ; Seidl, A.A. ; Thun, R. ; Willutzky, M. ; Beltrami, I. ; DeBonte, R. ; Gan, K.K. ; Koltick, D. ; Loeffler, F. ; Mallik, U. ; McIlwain, R. ; Miller, D.H. ; Ng, C.R. ; Ong, P.P. ; Rangan, L.K. ; Shibata, E.I. ; Stevens, R. ; Wilson, R.J. ; Wood, D.E. ; Cork, B. ; Keller, L. ; Va'vra, J. « less Publication Date:1985-01-01 OSTI Identifier:6247594 Resource Type:Journal Article Resource Relation:Journal Name: Phys. Rev. D; (United States); Journal Volume: 31:1 Research Org:Argonne National Laboratory, Argonne, Illinois 60439 Country of Publication:United States Language:English Subject: 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; HADRONS; ISOSPIN; MASS; QUARKS; EIGENSTATES; FLAVOR MODEL; QUANTUM CHROMODYNAMICS; S WAVES; SPIN; SU-3 GROUPS; SYMMETRY BREAKING; ANGULAR MOMENTUM; COMPOSITE MODELS; ELEMENTARY PARTICLES; FIELD THEORIES; LIE GROUPS; MATHEMATICAL MODELS; PARTIAL WAVES; PARTICLE MODELS; PARTICLE PROPERTIES; POSTULATED PARTICLES; QUANTUM FIELD THEORY; QUARK MODEL; SU GROUPS; SYMMETRY GROUPS 645204* -- High Energy Physics-- Particle Interactions & Properties-Theoretical-- Strong Interactions & Properties
01 Jan 1985
TL;DR: Perturbative QCD predictions are given for the e e pair production of vector and pseudoscalar hadrons which are bound states of heavy quarks.
Abstract: Perturbative QCD predictions are given for the e e pair production of vector and pseudoscalar hadrons which are bound states of heavy quarks. A striking result is the prediction of an exact zero above threshold for the production of helicity-zero hadron pairs.
TL;DR: Measurements of single-particles inclusive spectra and two-particle correlations in decays of the UPSILON(1S) resonance and in nonresonant annihilations of electrons and positrons at center-of-mass energy 10.49 GeV suggest baryon and antibaryon are more likely to be correlated at long range in upsilon decay than in continuum events.
Abstract: We report measurements of single-particle inclusive spectra and two-particle correlations in decays of the UPSILON(1S) resonance and in nonresonant annihilations of electrons and positrons at center-of-mass energy 10.49 GeV, just below BB-bar threshold. These data were obtained using the CLEO detector at the Cornell Electron Storage Ring (CESR) and provide information on the production of ..pi.., K, rho, K(, phi, p, ..lambda.., and ..xi.. in quark and gluon jets. The average multiplicity of hadrons per event for upsilon decays (compared with continuum annihilations) is 11.4 (10.5) pions, 2.4 (2.2) kaons, 0.6 (0.5) rho/sup 0/, 1.2 (0.8) K(, 0.6 (0.4) protons and antiprotons, 0.15 (0.08) phi, 0.19 (0.07) ..lambda.. and Lambda-bar, and 0.016 (0.005) ..xi../sup -/ and Xi-bar /sup +/. We have also seen evidence for eta and f/sup 0/ production. The most significant differences between upsilon and continuum final states are (1) the inclusive energy spectra fall off more rapidly with increasing particle energy in upsilon decays, (2) the production of heavier particles, especially baryons, is not as strongly suppressed in upsilon decays, and (3) baryon and antibaryon are more likely to be correlated at long range in upsilon decay than in continuum events.
01 Jan 1985
TL;DR: The SU(3) c × SU(2) L × U(1)Y model has been shown to accurately describe the interactions of quarks and leptons at energies below, say, 103 GeV as discussed by the authors.
Abstract: In the past five years or so progress in both elementary particle physics and in cosmology has become increasingly dependent upon the interplay between the two disciplines. On the particle physics side, the SU(3) c × SU(2) L × U(1)Y model seems to very accurately describe the interactions of quarks and leptons at energies below, say, 103 GeV. At the very least, the so-called standard model is a satisfactory, effective low energy theory. The frontiers of particle physics now involve energies of much greater than 103 GeV—energies which are not now available in terrestrial accelerators, nor are ever likely to be available in terrestrial accelerators. For this reason particle physicists have turned both to the early Universe with its essentially unlimited energy budget (up to 1019 GeV) and high particle fluxes (up to 10107cm-2s-1), and to various unique, contemporary astrophysical environments (centers of main sequence stars where temperatures reach 108 K, neutron stars where densities reach 1014 – 1015gcm-3, our galaxy whose magnetic field can impart 1011 GeV to a Dirac magnetic charge, etc.) as non-traditional laboratories for studying physics at very high energies and very short distances.
TL;DR: The constants of motion responsible for the spectrum degeneracy of a nonrelativistic spin-(1/2) particle in the field of a dyon are exhibited and two vector operators are conserved: One generalizes the Runge-Lenz vector while the other has no counterpart for spinless systems.
Abstract: The constants of motion responsible for the spectrum degeneracy of a nonrelativistic spin-\textonehalf{} particle in the field of a dyon are exhibited. In addition to angular momentum, two vector operators are conserved: One generalizes the Runge-Lenz vector while the other has no counterpart for spinless systems. At fixed energy, they satisfy closed commutation relations. An invariance superalgebra including these conserved quantities is discovered when the system is enlarged by the adjunction of a second spin-\textonehalf{} particle.
TL;DR: The neutron EDM in the Weinberg CP-violation model is shown to be dominated by the neutral Higgs boson interaction and to exceed the present experimental limitations by 2-3 orders of magnitude as mentioned in this paper.
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01 Jan 1985
TL;DR: In this paper, the static properties of baryons as chiral solitons, the fermion number of the vacuum, coherent state description of non-opological soliton and momentum projection, and a spinor soliton bag are discussed.
Abstract: This book presents paper on solitons in nuclear and elementary particle physics. Topics covered include: static properties of baryons as chiral solitons; centrifugal effects in skyrmions; fermion number of the vacuum; coherent state description of nontopological solitons and momentum projection; and a spinor soliton bag.
TL;DR: In a class of extended Higgs structures containing a light or massless pseudoscalar, it is quite likely the normal Wienberg-Salam Higgs particle decays preferentially into spin-zero bosons if its mass is below the t t threshold as discussed by the authors.
TL;DR: In this article, the pomeron interacts with a single valence quark and apparently back-scatters it, leading to a longitudinal event structure, and the subsequent hadronization leads to the Pomeron-proton scattering.
TL;DR: The Green's-function Monte Carlo method is used to calculate the ground-state wave function of the muonic-molecular ion, and the probability that the muon will remain bound to the escaping alpha particle after fusion occurs is found to be about 25% smaller than previous estimates.
Abstract: The Green's-function Monte Carlo method is used to calculate the ground-state wave function of the muonic-molecular ion composed of a negative muon bound to a deuteron and a triton. Using the sudden approximation, the probability that the muon will remain bound to the escaping alpha particle after fusion occurs is found to be 0.90%, about 25% smaller than previous estimates based on the Born-Oppenheimer approximation. The numerical method for determining the wave function is discussed in detail.
TL;DR: The model is so structured as to reproduce the results of recently developed relativistic models of nuclear structure in which the degrees of freedom are nucleons and mesons, and the central result is the prediction that nucleons will be bigger in the nucleus than in free space.
Abstract: We propose a model of nuclear structure in which the degrees of freedom are quarks and mesonic fields. The quarks are organized into nucleons which interact via the exchange of mesons (\ensuremath{\sigma},\ensuremath{\pi},\ensuremath{\rho},\ensuremath{\omega}). The model is so structured as to reproduce the results of recently developed relativistic models of nuclear structure in which the degrees of freedom are nucleons and mesons. The model used to describe nucleon structure is taken from a previous work in which a fully covariant (soliton) model of the nucleon was developed. The model also allows one to consider the dynamics of solitons in the presence of the fields generated by other solitons. This feature enables us to investigate the modification of nucleon properties when the nucleon is inside a nucleus. Our central result is the prediction that nucleons will be bigger in the nucleus than in free space. Evidence for this modification of nucleon properties is discussed. We consider deep inelastic electron scattering from nuclei: We discuss the European-Muon-Collaboration effect and some recent (e,e') experiments and relate the experimental results to our prediction of modified nucleon radii and form factors.
TL;DR: In this article, the Higgs mass and the ϒ decay branching ratio were calculated and a light supersymmetric Higgs may be lurking just beyond the sensitivity of present experiments on ϒ radiative decays.
TL;DR: In this paper, it was shown that at a high energy hadron collider, the subprocess gluon + gluons → quark + antiquark + lepton + antilepton is a severe background to the detection of a Higgs boson in the generally favored two W decay channel (when one W decays hadronically, the other leptonically) for Higgs masses up to and exceeding 1 TeV
TL;DR: A calculation is outlined and results presented for the electric form factor, measured at two values of the momentum, of the pseudo-Goldstone meson within the staggered formulation of lattice fermions.
Abstract: A calculation is outlined and results presented for the electric form factor, measured at two values of the momentum, of the pseudo-Goldstone meson within the staggered formulation of lattice fermions.
TL;DR: B bounds on charged-Higgs-boson masses and couplings in models with two Higgs doublets are obtained by considering their effect on neutral-B-meson mixing, comparable to those obtained with additional assumptions from the neutral-K system.
Abstract: We obtain bounds on charged-Higgs-boson masses and couplings in models with two Higgs doublets by considering their effect on neutral-B-meson mixing. Even with the present fairly loose experimental constraints, the bounds are comparable to those obtained with additional assumptions from the neutral-K system. Neutral-Higgs-boson effects on the spectrum and wave functions of t t-bar bound states are examined in the same model. In the future they could lead to restrictions on, or discovery of, the corresponding neutral Higgs bosons if they have relatively low masses and enhanced couplings.