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Topics in dual models and extended solutions. [Bethe-Salpeter equation]

Description: Two main topics are explored. The first deals with the infinities arising from the one loop planar string diagram of the standard dual model. It is shown that for the number of dimensions d = 25 or 26, these infinities lead to a renormalization of the slope of the Regge trajectories, in addition to a renormalization of the coupling constant. The second topic deals with the propagator for a confined particle (monopole) in a field theory. When summed to all orders, this propagator is altogether free of singularities in the finite momentum plane, and an attempt is made to illustrate this. One examines the Bethe-Salpeter equation and shows that ladder diagrams are not sufficient to obtain this result. However, in a nonrelativistic approximation confinement is obtained and all poles disappear.
Date: June 1, 1977
Creator: Roth, R. S.
Partner: UNT Libraries Government Documents Department

New particles and interactions

Description: The Working Group on New Particles and Interactions met as a whole at the beginning and at the end of the Workshop. However, much of what was accomplished was done in five subgroups. These were devoted to: (1) new quarks and leptons; (2) technicolor; (3) supersymmetry; (4) rare decays and CP; and (5) substructure of quarks and leptons. Other aspects of new particles, e.g., Higgs, W', Z', fell to the Electroweak Working Group to consider. The central question of this Workshop of comparing anti pp (with L = 10/sup 32//cm/sup 2/-sec) with pp (with L = 10/sup 33//cm/sup 2/-sec) colliders carried through to all these subgroups. In addition there were several other aspects of hadron colliders which were considered: what does an increase in ..sqrt..s gain in cross section and resultant sensitivity to new physics versus an increase in luminosity; will polarized beams or the use of asymmetries be essential in finding new interactions; where and at what level do rate limitations due to triggering or detection systems play a role; and how and where will the detection of particles with short, but detectable, lifetimes be important. 25 references.
Date: April 1, 1984
Creator: Gilman, F. J. & Grannis, P. D.
Partner: UNT Libraries Government Documents Department

Some global problems in gauge theories (Variations on a theme of Aharonov and Bohm)

Description: Several situations are discussed, in which the sort of global considerations made famous by Aharonov and Bohm in their discussion of the interaction of charged particles with magnetic flux tubes have important physical implications. It is argued that discrete gauge symmetries in the continuum make sense, and manifest themselves most clearly in Aharonov-Bohm type scattering of charged particles off string singularities. The existence of such discrete symmetries has important implications for the quantum mechanics of topologically non-trivial space-times in general and black holes in particular. It is argued that in the non-abelian case essentially new features arise, most notably that the symmetry group of the homogeneous ground state generally ceases to be globally defined in the presence of a string. When continuous rather than discrete symmetries are involved, a variety of fascinating and as yet poorly understood dynamical effects occur. Perhaps the most striking is a new form of string superconductivity, that exists for purely topological reasons, and is not well modeled by regarding the string as a superconducting wire. 8 refs., 2 figs.
Date: December 1, 1989
Creator: Wilczek, F.
Partner: UNT Libraries Government Documents Department

Has hadronic color been excited in neutrino experiments. [Cross sections]

Description: The effect of the massive ''color'' gluon excitation in charged current ..nu..N and anti..nu..N inclusive scattering is studied. The observed rise in sigma/sub c//sup anti..nu..//sigma/sub c//sup ..nu../ and (y)/sup anti..nu../ can be understood as a transient effect arising from the opening of hadronic ''color'' thresholds. This interpretation of the charged current neutrino phenomena does not call for the introduction of the right-handed current of the type (anti pn')/sub R/.
Date: June 1, 1976
Creator: Sidhu, D. P.; Mohapatra, R. N. & Pati, J. C.
Partner: UNT Libraries Government Documents Department

High energy hadron dynamics based on a Stochastic-field multi-eikonal theory

Description: Multi-eikonal theory, using a stoichastic-field representation for collective long range rapidity correlations, is developed and applied to the calculation of Regge pole parameters, high transverse momentum enhancements, and fluctuation patterns in rapidity densities. If a short-range-order model, such as the one-dimensional planar bootstrap, with only leading t-channel meson poles, is utilized as input to the multi-eikonal method, the pole spectrum is modified in three ways; promotion and renormalization of leading trajectories (suggesting an effective pomeron above unity at intermediate energies), and a proliferation of dynamical secondary trajectories, reminiscent of dual models. When transverse dimensions are included, the collective effects produce a growth with energy of large-P/sub tau/ inclusive cross-sections. Typical-event rapidity distributions, at energies of a few TeV, can be estimated by suitable approximations; the fluctuations give rise to ''domain'' patterns, which have the appearance of clusters separated by rapidity gaps. The relations between this approach to strong-interaction dynamics and a possible unification of weak, electromagnetic, and strong interactions are outlined.
Date: June 1, 1977
Creator: Arnold, R. C.
Partner: UNT Libraries Government Documents Department

Scalar quantum chromodynamics in two dimensions and parton model. [Scalar quarks, SU(N) groups]

Description: The SU(N) scalar quantum chromodynamics in two space-time dimensions in the large N limit are studied. This is the model of color gauge fields interacting with scalar quarks. It is found that the consensual properties of the four dimensional QCD, i.e., the infrared slavery, quark confinement, the charmonium picture etc. are all realized. Moreover, the current in this model mimics nicely the behaviors of current in the four dimensional QCD, in contrast to the original model of 't Hooft.
Date: May 1, 1977
Creator: Shei, S. S. & Tsao, H. S.
Partner: UNT Libraries Government Documents Department

Dynamical evolution of cosmic strings

Description: The author have studied by means of numerical simulations the dynamical evolution of a network of cosmic strings, both in the radiation and matter era. Our basic conclusion is that a scaling solution exists, i.e., the string energy density evolves as t/sup -2/. This means that the process by which long strings dump their energy into closed loops (which can gravitationally radiate away) is efficient enough to prevent the string domination over other forms of energy. This conclusion does not depend on the initial string energy density, nor on the various numerical parameters. On the other hand, the generated spectrum of loop sizes does depend on the value of our numerical lower cutoff (i.e., the minimum length of loop we allow to be chopped off the network). Furthermore, the network evolution is very different from what was assumed before), namely the creation of a few horizon sized loops per horizon volume and per hubble time, which subsequently fragment into about 10 smaller daughter loops. Rather, many tiny loops are directly cut from the network of infinite strings, and it appears that the only fundamental scale (the horizon) has been lost. This is probably because a fundamental ingredient had been overlooked, namely the kinks. These kinks are created in pairs at each intercommutation, and very rapidly, the long strings appear to be very kinky. Thus the number of long strings per horizon is still of the order of a few, but their total length is fairly large. Furthermore, a large number of kinks favors the formation of small loops, and their sizes might well be governed by the kink density along the long strings. Finally, we computed the two-point correlation function of the loops and found significant differences from the work of Turok.
Date: May 11, 1988
Creator: Bouchet, F. R.
Partner: UNT Libraries Government Documents Department

Five-quark model with flavour-changing neutral current and dimuon events

Description: The recent dimuon data seem to suggest either the necessity of flavor-changing hadronic neutral current or proliferation of quarks beyond charm or both. It is shown how a five-quark model based on simple gauge group SU(2) x U(1) x U(1)' can generate the flavor-changing, in particular the needed charm-changing, neutral current in a natural fashion. A substantial D/sup 0/--D/sup -0/ mixing can be obtained to account for the ''wrong-sign'' dimuons observed in ..nu../sub ..mu../-induced reactions. Because of the role of the extra neutral boson in this model, the flavor-changing neutral current is decoupled from leptonic sectors, thus suppressing the trimuon events as experiments indicate thus far.
Date: January 1, 1976
Creator: Kim, J. E. & Kang, K.
Partner: UNT Libraries Government Documents Department

(Research in elementary particles and interactions). [1992]

Description: Research of the Yale University groups in the areas of elementary particles and their interactions are outlined. Work on the following topics is reported: development of CDF trigger system; SSC detector development; study of heavy flavors at TPL; search for composite objects produced in relativistic heavy-ion collisions; high-energy polarized lepton-nucleon scattering; rare K{sup +} decays; unpolarized high-energy muon scattering; muon anomalous magnetic moment; theoretical high-energy physics including gauge theories, symmetry breaking, string theory, and gravitation theory; study of e{sup +}e{sup {minus}} interactions with the SLD detector at SLAC; and the production and decay of particles containing charm and beauty quarks.
Date: May 1, 1992
Creator: Adair, R.; Sandweiss, J. & Schmidt, M.
Partner: UNT Libraries Government Documents Department

Higher order effects of pseudoparticles in QCD

Description: Gauge invariant Green's functions of quark-antiquark bilinear densities in massless, two-color QCD are studied. Nonzero-energy fermion modes, pseudoparticle solutions with topological charge absolute value ..nu.. > 1, and n-point functions with n > 2. Some general properties of the O(Dirac constant) approximation are developed, enabling one to isolate and define the terms which contribute to a general n-point function. The higher effects it is found preserve the symmetry breakdown found earlier in the 2-point function (U(2) x U(2) ..-->.. SU(2) x SU(2) x U(1)). It is shown that a previous 2-point function analysis is exact to order Dirac constant.
Date: January 1, 1977
Creator: Hietarinta, J. & Palmer, W. F.
Partner: UNT Libraries Government Documents Department

Models of multiquark states

Description: The success of simple constituent quark models in single-hardon physics and their failure in multiquark physics is discussed, emphasizing the relation between meson and baryon spectra, hidden color and the color matrix, breakup decay modes, coupled channels, and hadron-hadron interactions via flipping and tunneling of flux tubes. Model-independent predictions for possible multiquark bound states are considered and the most promising candidates suggested. A quark approach to baryon-baryon interactions is discussed.
Date: January 1, 1986
Creator: Lipkin, H. J.
Partner: UNT Libraries Government Documents Department

N-loop string amplitude

Description: Work on the derivation of an explicit perturbation series for string and superstring amplitudes is reviewed. The light-cone approach is emphasized, but some work on the Polyakov approach is also mentioned, and the two methods are compared. The calculation of the measure factor is outlined in the interacting-string picture. (LEW)
Date: June 1, 1986
Creator: Mandelstam, S.
Partner: UNT Libraries Government Documents Department

Spectroscopy of the D-wave q[bar q] system; evidence for two J[sup P] = 2[sup [minus]] strange meson states decaying to K[sup [minus]][omega]

Description: Evidence is presented for two J[sup p] = 2[minus] strange mesons; one at [approx] 1.77 and the other at [approx] 1.82 GeV/c[sup 2]. These states have been observed in a partial wave analysis of the K[sup [minus]][omega] system in the reaction K[sup [minus]]p [yields] K[sup [minus]][pi]+[pi][sup [minus]][pi][sup 0]p where the strange mesons decay into K[sup [minus]][omega] and the [omega] then decays to [pi]+[pi][sup [minus]][pi][sup 0]. The data set contains [approx] 10[sup 5] K[sup [minus]][omega]p events at 11 GeV/c taken with the LASS spectrometer at SLAC.
Date: September 1, 1992
Creator: Ratcliff, B. N.; Aston, D.; Bienz, T.; Bird, F.; Dunwoodie, W.; Johnson, W. B. et al.
Partner: UNT Libraries Government Documents Department

Comment on Flavor-changing processes and CP violation in the S sub 3 times Z sub 3 model''

Description: Deshpande, Gupta and Pal neglected the presence of a complex phase in the mass matrix and in the Yukawa coupling matrices of the down-type quarks I argue that phase should not be neglected, because it can explain the observed CP violation. The mechanism of CP violation considered by those authors may certainly be present, but for simplicity one may want to eliminate it, by restricting the soft-breaking sector of the Higgs potential in such a way that complex Higgs bosons propagators do not occur.
Date: April 28, 1992
Creator: Lavoura, L.
Partner: UNT Libraries Government Documents Department

Twisted strings and orbifolds

Description: Orbifold compactifications provide a practical approach to string symmetry breaking. They have the potential to bridge the gap between string theory and the physics of the standard model. 7 refs., 5 figs.
Date: August 1, 1986
Creator: Bagger, J. A.
Partner: UNT Libraries Government Documents Department

A Cloudy Quark Bag Model of S, P, and D wave interactions for the coupled channel antikaon-nucleon system

Description: The Cloudy Quark Bag Model is extended from S-wave to P- and D-wave. The parameters of the model are determined by K{sup {minus}}p scattering cross section data, K{sup {minus}}p {yields}{Sigma}{pi}{pi}{pi} production data, K{sup {minus}}p threshold branching ratio data, and K{sup {minus}}p {yields}{Lambda}{pi}{pi}{pi} production data. The resonance structure of the {Lambda}(1405), {Sigma}(1385), and {Lambda}(1520) are studied in the model. The shift and width of kaonic hydrogen are calculated using the model.
Date: May 15, 1992
Creator: He, Guangliang.
Partner: UNT Libraries Government Documents Department

Properties of gluon jets

Description: The properties of gluon jets are reviewed from an experimental point of view. The measured characteristics are compared to theoretical expectations. Although neither data nor models for the gluon jets are in the mature stage, there are remarkable agreements and also intriguing disagreements between experiment and theory. Since much interesting data have begun to emerge from various experiments and the properties of gluon jets are deeply rooted in the basic structure of non-Abelian gauge theory, the study of gluon jets casts further light on our understanding of QCD. Finally, the future prospects are discussed.
Date: September 1, 1986
Creator: Sugano, K.
Partner: UNT Libraries Government Documents Department

Generalization of the quark rearrangement model. [Quark-parton model]

Description: An extension and generalization of the quark rearrangement model of baryon annihilation is described which can be applied to all annihilation reactions and which incorporates some of the features of the highly successful quark parton model. Some p anti-p interactions are discussed. (JFP)
Date: January 1, 1976
Creator: Fields, T. & Chen, C. K.
Partner: UNT Libraries Government Documents Department

X spectroscopy and newer particles. [Branching ratios, angular distributions]

Description: Two recent results from the SPEAR Magnetic detector are covered. A study of psi' ..-->.. ..gamma.. + X, ..gamma gamma..psi, ..gamma../sup +/ hadrons is presented; four intermediate states are seen, branching fractions and production angular distribution are given, which agree with the predictions of the charm quark model. Evidence is presented for 2 narrow new states (charges 0 and 1) decaying to a kaon and pions. Structures are seen in the recoil mass spectra. The production and decay characteristics support the assignment of those states as the low lying nonstrange charmed mesons.
Date: August 1, 1976
Creator: Pierre, F.
Partner: UNT Libraries Government Documents Department

Construction of four-dimensional open superstrings

Description: We present the first examples of space-time supersymmetric one-loop finite four-dimensional open superstrings. 21 refs., 1 fig.
Date: January 1, 1989
Creator: Bern, Z. (Los Alamos National Lab., NM (USA)) & Dunbar, D. C. (Liverpool Univ. (UK). Dept. of Applied Mathematics and Theoretical Physics)
Partner: UNT Libraries Government Documents Department

Intermediate scales of symmetry breaking in Calabi-Yau models

Description: We discuss the generation of large intermediate scales of symmetry breaking in grand unification models suggested by the heterotic string. We analyze on dimensional grounds a particular scenario where one flat direction in the effective potential defines two different scales of gauge-symmetry breaking at very high energies ({approx}0(10{sup 15}GeV)). This mechanism implies the presence of one light (0(1 TeV)) nonchiral neutrino. The size of the observable low-energy effects seems, however, quite model dependent.
Date: January 1, 1992
Creator: Masip, M.
Partner: UNT Libraries Government Documents Department