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Item RESONANCES IN SU(2) GAUGE THEORY(American Physical Society, 1977-06-15) Stern, A; Syracuse University; University of Alabama TuscaloosaShow more Classical periodic trajectories are shown to exist for a test particle moving in an external SU(2) gauge field. The field is assumed to be static and of the form proposed by Wu and Yang. The energy of the system is positive, so the orbits are expected to give rise to a spectrum of metastable states. A Bohr-Sommerfeld quantization scheme is proposed for finding the spectrum. The results are applied to the problem of a particle interacting with a Polyakov-'t Hooft monopole, via the explicit solution of Prasad and Sommerfield. © 1977 The American Physical Society.Show more Item ANALYTICITY OF CHARGE-MONOPOLE SCATTERING-AMPLITUDE(American Physical Society, 1978-02-15) Balachandran, AP; Borchardt, S; Chang, SS; Stern, A; Cahalan, R; Ramachandran, R; Rupertsberger, H; Indian Institute of Science (IISC) - Bangalore; Western Kentucky University; Indian Institute of Technology System (IIT System); Indian Institute of Technology (IIT) - Kanpur; University of Vienna; University of Alabama TuscaloosaShow more We study the analyticity in cost of the exact quantum-mechanical electric-charge-magnetic-monopole scattering amplitude by ascribing meaning to its formally divergent partial-wave expansion as the boundary value of an analytic function. This permits us to find an integral representation for the amplitude which displays its analytic structure. On the physical sheet we find only a branch-point singularity in the forward direction, while on each of the infinitely many unphysical sheets we find a logarithmic branch-point singularity in the backward direction as well as the same forward structure. © 1978 The American Physical Society.Show more Item ROTATIONALLY INVARIANT APPROXIMATION TO CHARGE-MONOPOLE SCATTERING(American Physical Society, 1978-02-15) Balachandran, AP; Borchardt, S; Chang, SS; Stern, A; Cahalan, R; Ramachandran, R; Rupertsberger, H; Western Kentucky University; Indian Institute of Technology System (IIT System); Indian Institute of Technology (IIT) - Kanpur; University of Vienna; University of Alabama TuscaloosaShow more A semiclassical approximation derived directly from the Feynman path integral is employed in the study of electric-charge-magnetic-monopole scattering. We show that this approximation, unlike perturbation theory, is consistent with rotational invariance. The semiclassical cross section is explicitly evaluated. It differs from the classical differential cross section for sufficiently large scattering angles due to the interference between the several classical trajectories contributing to the scattering at such angles. It is found that when the scattering angle is not too near the backward direction the semiclassical cross section approaches the classical limit rather slowly as the Dirac quantization number becomes large, or equally as 0 with the product of electric and magnetic charges held fixed. © 1978 The American Physical Society.Show more Item LAGRANGIAN AND HAMILTONIAN DESCRIPTIONS OF YANG-MILLS PARTICLES(American Physical Society, 1978-06-15) Balachandran, AP; Borchardt, S; Stern, A; Indian Institute of Science (IISC) - Bangalore; Western Kentucky University; Indian Institute of Technology System (IIT System); Indian Institute of Technology (IIT) - Kanpur; University of Vienna; University of Alabama TuscaloosaShow more A new Lagrangian L is proposed for the description of a particle with a non-Abelian charge in interaction with a Yang-Mills field. The canonical quantization of L is discussed. At the quantum level L leads to both irreducible and reducible multiplets of the particle depending upon which of the parameters in L are regarded as dynamical. The case which leads to the irreducible multiplet is the minimal non-Abelian generalization of the usual Lagrangian for a charged point particle in an electromagnetic field. Some of the Lagrangians proposed before for such systems are either special cases of ours or can be obtained from ours by simple modifications. Our formulation bears some resemblance to Dirac's theory of magnetic monopoles in the following respects: (1) Quantization is possible only if the values of certain parameters in L are restricted to a certain discrete set, this is analogous to the Dirac quantization condition; (2) in certain cases, L depends on external (nondynamical) directions in the internal-symmetry space. This is analogous to the dependence of the magnetic-monopole Lagrangian on the direction of the Dirac string. © 1978 The American Physical Society.Show more Item CORRECTION(American Physical Society, 1978-06-15) Balachandran, AP; Indian Institute of Science (IISC) - Bangalore; Western Kentucky University; Indian Institute of Technology System (IIT System); Indian Institute of Technology (IIT) - Kanpur; University of Vienna; University of Alabama TuscaloosaShow more Item DISTRIBUTIONS OF GLOBULAR CLUSTERS IN GALAXY AND IN MESSIER-31(American Institute of Physics, 1978-11) Devaucouleurs, G; Buta, R; University of Texas System; University of Texas Austin; University of Alabama TuscaloosaShow more Item NON-LINEAR MODELS AS GAUGE-THEORIES(American Physical Society, 1979-04-15) Balachandran, AP; Stern, A; Trahern, G; European Organization for Nuclear Research (CERN); University of Texas System; University of Texas Austin; University of Alabama TuscaloosaShow more In the usual formulation of nonlinear models (such as chiral models), there is invariance under a nonlinear realization of a group GF which becomes linear when restricted to a subgroup HF. We formulate them so that they become gauge theories for a local group HC. It is the local version of a global group HC. When the gauge transformations are unrestricted at spatial infinity, only HC singlets are observable, and the usual formulation is recovered. When the gauge transformations are required to reduce to identity at spatial infinity, the usual formulation is no longer recovered. In particular, (1) nonsinglets under HC become observable, (2) the classical vacuum becomes degenerate under suitable conditions as in Yang-Mills theories, (3) the spontaneous symmetry breakdown of GF seems complete. (In the usual formulations, GF is broken down only to HF.) It is shown that the instanton and meron solutions of Yang-Mills theories are also solutions of certain nonlinear models. It is also shown that in a certain class of nonlinear models in (Euclidean) (3 + 1)-dimensional space-time, there are no instanton solutions for any choice of the groups. © 1979 The American Physical Society.Show more Item GAUGE-THEORY OF EXTENDED OBJECTS(American Physical Society, 1979-07-15) Balachandran, AP; Stern, A; Skagerstam, BS; European Organization for Nuclear Research (CERN); University of Texas System; University of Texas Austin; University of Alabama TuscaloosaShow more Equations of motion and the Lagrangian formalism for extended objects coupled to Abelian and non-Abelian gauge fields are developed. These equations are minimal generalizations of the corresponding equations for point particles. It is seen that the string superconducts when it couples to an Abelian gauge field. Further, in this case, (a) the total charge on it is quantized, and (b) the total magnetic flux through it is quantized and conserved if it is closed and no segment of it is electrically neutral. The Lagrangians which lead to the equations of motion are not unique. Here, for a suitable Lagrangian, property (a) emerges at the classical level, the total charge being a topological invariant which labels the elements of 1[U(1)]. Both of these properties partially generalize to other extended objects and non-Abelian gauge fields. It is pointed out that for some Lagrangians, extended objects may have topological invariants (the analogs of total charge) for any gauge group. Supersymmetric extensions of the interaction Lagrangians are also outlined. For a point particle, such an extension correctly describes a spin-half particle in an Abelian or a non-Abelian gauge field. © 1979 The American Physical Society.Show more Item LIGHT VARIATIONS OF NONRADIAL PULSATORS - THEORY AND APPLICATION TO THE LINE-PROFILE VARIABLE 53-PERSEI(University of Chicago Press, 1979-08) Buta, RJ; Smith, MA; University of Texas System; University of Texas Austin; University of Alabama TuscaloosaShow more Item NONRADIAL MODE-IDENTIFICATION OF 53 PERSEI DURING LATE 1977 AND 1978(University of Chicago Press, 1979-09) Smith, MA; Buta, RJ; University of Texas System; University of Texas Austin; University of Alabama TuscaloosaShow more Item DIAMETERS OF NUCLEI, LENSES, AND INNER AND OUTER RINGS IN 532 GALAXIES(IOP Publishing, 1980-06) Devaucouleurs, G; Buta, R; University of Texas System; University of Texas Austin; University of Alabama TuscaloosaShow more Item IDENTIFICATION OF A NEBULOUS BLUE OBJECT NEAR MAFFEI-1(Astronomical Society of the Pacific, 1980-10) Buta, RJ; Mccall, ML; Uomoto, AK; University of Texas System; University of Texas Austin; University of Alabama TuscaloosaShow more Item Physics(1980-10-01) Sandy, John H.Show more Item INNER RING STRUCTURES IN GALAXIES AS DISTANCE INDICATORS .1. DIMENSIONLESS SYSTEMATICS OF INNER RINGS(University of Chicago Press, 1980-12) Devaucouleurs, G; Buta, R; University of Texas System; University of Texas Austin; University of Alabama TuscaloosaShow more Item INTEGRATED MAGNITUDES AND MEAN COLORS OF THE DDO DWARF GALAXIES IN THE UBV SYSTEM .1. OBSERVATIONS AND CATALOG(American Institute of Physics, 1981-10) Devaucouleurs, G; Devaucouleurs, A; Buta, R; University of Texas System; University of Texas Austin; University of Alabama TuscaloosaShow more Item INTERPRETATION OF THE MAXIMUM LIGHT SPECTRUM OF A TYPE-I SUPER-NOVA(University of Chicago Press, 1982-01) Branch, D; Buta, R; Falk, SW; Mccall, ML; Sutherland, PG; Uomoto, A; Wheeler, JC; Wills, BJ; University of Texas System; University of Texas Austin; University of Alabama TuscaloosaShow more Item INNER RING STRUCTURES IN GALAXIES AS DISTANCE INDICATORS .2. CALIBRATION OF INNER RING DIAMETERS AS QUATERNARY INDICATORS(University of Chicago Press, 1982-02) Buta, R; Devaucouleurs, G; University of Texas System; University of Texas Austin; University of Alabama TuscaloosaShow more Item SUPERCONDUCTING EXTENDED OBJECTS AND APPLICATIONS TO THE PHASE-STRUCTURE OF QUANTUM CHROMODYNAMICS(American Physical Society, 1982-03-15) Skagerstam, BS; Stern, A; European Organization for Nuclear Research (CERN); University of Texas System; University of Texas Austin; University of Alabama TuscaloosaShow more In a previous work the dynamics of relativistic extended objects (i.e., strings, shells, etc.) coupled to Abelian or non-Abelian gauge fields was developed. The extended objects possessed an electriclike current which was defined in the associated Lie algebra of the gauge group under consideration. In the present paper, the interaction between the extended objects and gauge fields is slightly modified so that the objects behave like superconductors. By this we mean (a) the electrical conductivity is infinite and (b) for objects other than strings, a magnetic shielding or Meissner effect (with zero penetration depth) is present. Both (a) and (b) are features which occur in the classical description of the system. We also develop the dynamics for a system which is dual to the one described above. That is, instead of possessing an electric current, the objects here carry a magnetic current (Abelian or non-Abelian). Furthermore, the magnetic conductivity is infinite, and for objects other than strings an electric shielding or "dual" Meissner effect is present. The systems developed here contain Dirac's extended electron model and the MIT bag model as special cases. The former coincides with the description of an electrically charged shell. In the latter, we verify that the dynamics of a cavity within a (magnetic) superconducting vacuum is identical to that of a glueball in the MIT bag. This agrees with the view that the true quantum-chromodynamic (QCD) vacuum may be in a magnetic superconducting phase, and that the "dual" Meissner effect may be relevant for the confinement question. We also examine the possibility of the QCD vacuum being in an electric (or conventional) superconducting phase and a mixed superconducting phase, and comment on the confinement question for these two cases. © 1982 The American Physical Society.Show more Item NONLOCAL CONSERVATION-LAWS FOR STRINGS(American Physical Society, 1982-09-15) Balachandran, AP; Stern, A; University of Texas System; University of Texas Austin; University of Alabama TuscaloosaShow more A finite number of nonlocal conservation laws are found in the Nambu-Goto string model. An infinite number of conserved currents may be obtained by embedding the string in more than 3 + 1 space-time dimensions. These currents resemble the nonlocal currents found in two-dimensional chiral models. © 1982 The American Physical Society.Show more Item STRUCTURE OF PROTON DECAY IN SO(N) FAMILY UNIFICATION(American Physical Society, 1982-10-15) Nandi, S; Stern, A; Sudarshan, ECG; University of Texas System; University of Texas Austin; University of Alabama TuscaloosaShow more We show that for all SO(n), n>10, family unification schemes there exist no gauge currents relevant for baryon decay other than those already appearing in the SO(10) model. The effect of Yukawa interactions for baryon-number- violating processes in SO(n) models is also investigated. © 1982 The American Physical Society.Show more