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August 1993 arXiv papers — page 6

Showing 501543 of 543 papers

  1. Edi Halyo

    We find that there are three axions in standard--like superstring models in the four dimensional free fermionic formulation. These axions are either harmful or very heavy. Therefore, they cannot solve the strong CP problem. We show that this is a general result in superstring models with chiral generations from the $Z_2$ twisted sectors which use a $Z_4$ twi

  2. S. L. Pepke, J. M. Carlson, B. E. Shaw

    We present results for long term and intermediate term prediction algorithms applied to a simple mechanical model of a fault. We use long term prediction methods based, for example, on the distribution of repeat times between large events to establish a benchmark for predictability in the model. In comparison, intermediate term prediction techniques, analogo

  3. Akira Ono, Hisashi Horiuchi, Toshiki Maruyama

    The collective flow of nucleons and that of fragments in the 12C + 12C reaction below 150 MeV/nucleon are calculated with the antisymmetrized version of molecular dynamics combined with the statistical decay calculation. Density dependent Gogny force is used as the effective interaction. The calculated balance energy is about 100 MeV/nucleon, which is close

  4. Robert Marnelius

    In a previous paper \cite{Simple} it was shown that the BRST charge $Q$ for any gauge model with a Lie algebra symmetry may be decomposed as $Q=\del+\del^†,\;\;\;\del^2=\del^{†2}=0,\;\;\;[\del, \del^†]_+=0$ provided dynamical Lagrange multipliers are used but without introducing other matter variables in $\del$ than the gauge generators in $Q$. In this paper

  5. C. Acerbi, A. Bassetto

    We generalize to composite operators concepts and techniques which have been successful in proving renormalization of the effective Action in light-cone gauge. Gauge invariant operators can be grouped into classes, closed under renormalization, which is matrix-wise. In spite of the presence of non-local counterterms, an ``effective" dimensional hierarchy

  6. Ernest Ma

    Contrary to common belief, the requirement that supersymmetry exists and that there are two Higgs doublets and no singlet at the electroweak energy scale does not necessarily result in the minimal supersymmetric standard model (MSSM). Two interesting alternatives are presented.

  7. I. P. Ivanenko, V. V. Kopenkin, A. K. Managadze, I. V. Rakobolskaya

    Alignment of main fluxes of energy in a target plane is found in families of cosmic ray particles detected in deep lead X-ray emulsion chambers. The fraction of aligned events becomes unexpectedly large for superfamilies with the total energy of gamma-quanta exceeding $10^3$ TeV. This can be considered as an evidence of existence of coplanar scattering of se

  8. K. S. Babu, S. M. Barr

    Spontaneous CP--violation in the minimal supersymmetric standard model with a gauge singlet and a cubic superpotential is examined. Although the tree--level Higgs potential conserves CP, it is shown that with the inclusion of the one--loop top--quark radiative effects, CP may be broken spontaneously. The CP--violating minimum requires two neutral $(h_1,h_2)$

  9. V. Barger, J. Ohnemus, R. J. N. Phillips

    Single-lepton plus jets signals from $t\bar t$ production at hadron colliders generally give more spherically symmetrical events than the principal backgrounds from $W$ production. We show that sphericity and aplanarity criteria, applied to lepton plus neutrino plus four jet final states at the Fermilab Tevatron $p\bar p$ collider, help to discriminate; they

  10. G. K. Leontaris

    Exact low energy expressions are derived for the top-squark and higgs masses, taking into account radiative contributions due to a heavy top quark. Their masses are expressed as analytic functions of $m_{1/2}$, $m_{3/2}$, $m_t$ and $sinβ$. Constraints from the radiative symmetry breaking mechanism are used then, to put lower bounds on the top-quark mass $m_t

  11. N. Tetradis, C. Wetterich

    We compute the critical behaviour of three-dimensional scalar theories using a new exact non-perturbative evolution equation. Our values for the critical exponents agree well with previous precision estimates.

  12. Howard Georgi, Samuel T. Osofsky

    We explain how nonperturbative effects can be systematically included when constructing an effective field theory. We concentrate in particular on the matching calculation, by which a low energy theory without a heavy particle degree of freedom is matched onto the full theory. The matching calculation requires some new formalism, because for a large class of

  13. A. Deandrea, N. Di Bartolomeo, R. Gatto, G. Nardulli

    We perform an analysis of two-body non leptonic decays of $B$ and $B_s$ mesons in the factorization approximation. We make use of the semileptonic decay amplitudes previously calculated on the basis of an effective lagrangian satisfying chiral and heavy quark symmetries and including spin 1 resonances. Exclusive semileptonic $D$-decay data are used as experi

  14. Howard E. Haber

    Ten reasons are given why supersymmetry is the leading candidate for physics beyond the Standard Model. Ultimately, the experimental discovery of supersymmetric particles at future colliders will determine whether supersymmetry is relevant for TeV scale physics. The grand hope of supersymmetry enthusiasts is to connect TeV scale supersymmetry with Planck sca

  15. Rajan Gupta

    I give a brief introduction to the scope of lattice QCD calculations in our effort to extract the fundamental parameters of the standard model. This goal is illustrated by two examples. First I discuss the extraction of CKM matrix elements from measurements of form factors for semi-leptonic decays of heavy-light pseudoscalar mesons such as $D \to Keν$. Secon

  16. Enzo Marinari, Giorgio Parisi

    We consider the dynamics of a simple one dimensional model and we discuss the phenomenon of aging (i.e., the strong dependence of the dynamical correlation functions over the waiting time). Our model is the so-called random random walk, the toy model of a directed polymer evolving in a random medium.

  17. A. Parola, S. Sorella, Q. F. Zhong

    The ground state properties of the two dimensional spatially anisotropic Heisenberg model are investigated by use of field theory mappings, spin-wave expansion and Lanczos technique. Evidence for a disorder transition induced by anisotropy at about $J_y/J_x < 0.1$ is shown. We argue that the disordered phase is gapless and its long wavelength properties can

  18. D. D. Dixon

    Non-deterministic chaos is a form of low-dimensional dynamics which is characterized by the existence of a countable set of {\em sensitive decision points} (SDP&#39;s). Away from these points, the dynamics is well-behaved. Near these points, however, perturbations (e.g., thermal noise) may cause the outgoing trajectory to be chosen randomly. An example of a

  19. Alberto Albano, Alberto Collino

    We prove that the Griffiths group of 3-cycles homologous to zero modulo algebraic equivalence, on a generic hypersurfaces of dimension 7 and degree 3 is not finitely generated, even when tensored with Q. Using this and a result of Nori, we give examples of varieties for which some Griffiths group is not finitely generated (modulo torsion) but whose correspon

  20. Guangliang He, Rubin. H. Landau

    The cloudy quark bag model is applied to the coupled ($\Kbar N$, $Σπ$, $Λπ$) system for $S-D$ partial waves. Energy--dependent separable potentials are derived, as are new numerical algorithms for solving the coupled Lippmann-Schwinger equations. The parameters are fit to $K^-p$ scattering and reaction cross sections, branching ratios, and mass spectra from

  21. V. V. Dodonov, O. V. Man'ko, V. I. Man'ko

    For one-mode light described by the Wigner function of generic Gaussian form the photon distribution function is obtained explicitly and expressed in terms of Hermite polynomials of two variables.The mean values and dispersions of photon numbers are obtained for this generic %mixed state.Generating function for photon distribution is discussed.Known partial

  22. Per Berglund, Philip Candelas, Xenia de la Ossa, Anamaria Font

    The complete structure of the moduli space of \cys\ and the associated Landau-Ginzburg theories, and hence also of the corresponding low-energy effective theory that results from (2,2) superstring compactification, may be determined in terms of certain holomorphic functions called periods. These periods are shown to be readily calculable for a great many suc

  23. M. C. Land, N. Shnerb, L. P. Horwitz

    In 1948, Feynman showed Dyson how the Lorentz force and Maxwell equations could be derived from commutation relations coordinates and velocities. Several authors noted that the derived equations are not Lorentz covariant and so are not the standard Maxwell theory. In particular, Hojman and Shepley proved that the existence of commutation relations is a stron

  24. E. K. Heide, S. Rudaz, P. J. Ellis

    We study nuclear matter and finite nuclei with a chiral Lagrangian which generalizes the linear $σ$ model and also accounts for the QCD trace anomaly by means of terms which involve the $σ$ and $\vmgπ$ fields as well as the glueball field $ϕ$. The form of the scale invariant term leading to an omega meson mass, after symmetry breaking, could involve coupling

  25. S. Y. Tsay Tzeng, P. J. Ellis, T. T. S. Kuo, E. Osnes

    We have compared exact numerical results for the Lipkin model at finite temperature with Hartree-Fock theory and with the results of including in addition the ring diagrams. In the simplest version of the Lipkin model the Hartree-Fock approach shows a ``phase transition&#34; which is absent in the exact results. For more realistic cases, Hartree-Fock provide

  26. Sergey V. Shabanov

    The physical phase space of gauge field theories on a cylindrical spacetime with an arbitrary compact simple gauge group is shown to be the quotient $ {\bf R}^{2r}/W_A, $ $ r $ a rank of the gauge group, $ W_A $ the affine Weyl group. The PI formula resulting from Dirac&#39;s operator method contains a symmetrization with respect to $ W_A $ rather than the i

  27. H. Hata

    We propose a new formulation of gauge theories as a quantum theory which has the gauge theory action $S$ as its dynamical variable. This system is described by a simple actional $I(S)$ (that is, an action for the action $S$) whose equation of motion gives the Batalin-Vilkovisky (BV) master equation for $S$. Upon quantization we find that our new formulation

  28. A. Ali, G. F. Giudice, T. Mannel

    Motivated by the experimental accessibility of rare $B$ decays in the ongoing and planned experiments, we propose to undertake a model-independent analysis of the inclusive decay rates and distributions in the processes \bgamaxs~ and \Bsell ~($B=B^\pm$ or $B^0_d$). We show how measurements of the decay rates and distributions in these processes would allow u

  29. A. Lleida, C. Munoz

    The existence of non--universal soft masses is the most general situation in supersymmetric theories. We study the consecuences that this situation has for the low--energy sparticle spectrum. In particular, we analize in detail the contribution to the scalar mass renormalization group equations of the $U(1)_Y$ D--term. We obtain analytic expressions for the

  30. Vittorio Del Duca, Wai-Keung Tang

    The theory of the perturbative pomeron, due to Lipatov and collaborators, is used to compute the probability of observing parton-parton elastic scattering and rapidity gaps between jets in hadron collisions at Tevatron energies.

  31. Vittorio Del Duca

    The theory of the perturbative pomeron, due to Lipatov and collaborators, is used to compute the probability of observing parton-parton elastic scattering and rapidity gaps between jets in hadron collisions at SSC and LHC energies.

  32. Christopher D. Carone, Howard Georgi

    We consider a minimal technicolor model in which the ordinary and technicolor sectors are coupled by a {\it massless} scalar doublet. When technicolor interactions become strong, the resulting technicolor condensate not only breaks the electroweak symmetry, but also causes the scalar to develop a vacuum expectation value. With the appropriate choice of the s

  33. Hai-Yang Cheng

    It is stressed that a measurement of the electric dipole amplitude for direct photon emission in $\kpm$ decays through its interference with inner bremsstrahlung is important for differentiating among various models. Effects of amplitude CP violation in the radiative decays of the charged kaon are analyzed in the Standard Model in conjunction with the large

  34. V. A. Novikov, L. B. Okun, M. I. Vysotsky

    The Born approximation, based on $\barα\equivα(m_Z)$ instead of $α$, reproduces all electroweak precision measurements within their $(1σ)$ accuracy. The low upper limits for the genuinely electroweak corrections constitute one of the major achievements of LEP. The astonishing smallness of these corrections results from the cancellation of a large positive co

  35. Probir Roy

    PREAMBLE, BRIEF HISTORY AND PRELIMINARIES, QUICK REVIEW OF BASIC NEUTRINO PROPERTIES, CHARGED CURRENT NEUTRINO PROCESSES, NEUTRAL CURRENT NEUTRINO PROCESSES, VERY HEAVY NEUTRINOS, CONCLUDING SUMMARY

  36. Carsten Grosse-Knetter

    The equivalence of correct Hamiltonian and naive Lagrangian (Faddeev--Popov) path integral quantization (Matthews&#39;s theorem) is proven for gauge theories with arbitrary effective interaction terms. Effective gauge-boson self-interactions and effective interactions with scalar and fermion fields are considered. This result becomes extended to effective ga

  37. C. S. Kim, Jungil Lee, H. S. Song

    We investigate the sensitivity of total cross sections of $e+p \rightarrow W,Z$ to CP-conserving non-standard $WWγ$ couplings. We include all the important production mechanisms and study the dependence of the total $W$ cross sections on the anomalous $WWγ$ couplings, $κ$ and $λ$. We argue that the ratio of $W$ and $Z$ production cross sections is particular

  38. C. Gong

    We develop a method for calculating the Lyapunov characteristic exponents of lattice gauge theories. The complete Lyapunov spectrum of SU(2) gauge theory is obtained and Kolmogorov-Sinai entropy is calculated. Rapid convergence with lattice size is found.

  39. Sandro Sorella

    The two dimensional Hubbard model with a single spin-up electron interacting with a finite density of spin-down electrons is studied using the quantum Monte Carlotechnique, a new conjugate gradient method for the evaluation of the Edwards wavefunction ansatz, and the standard second order perturbation theory. We performed simulations up to 242 sites at $U/t=

  40. Y. Koyama

    In this paper we give an explicit formula for level 1 vertex operators related to $U_q(\widehat{sl}(n))$ as operators on the Fock spaces. We derive also their commutation relations. As an applications we culculate the one point functions of the one-dimensional spin chain associated with the vector representation of $U_q(\widehat{sl}(n))$, thereby extending t

  41. M. P. Wellman

    Market price systems constitute a well-understood class of mechanisms that under certain conditions provide effective decentralization of decision making with minimal communication overhead. In a market-oriented programming approach to distributed problem solving, we derive the activities and resource allocations for a set of computational agents by computin

  42. M. L. Ginsberg

    Because of their occasional need to return to shallow points in a search tree, existing backtracking methods can sometimes erase meaningful progress toward solving a search problem. In this paper, we present a method by which backtrack points can be moved deeper in the search space, thereby avoiding this difficulty. The technique developed is a variant of de

  43. A. A. Ovchinnikov

    We obtain the variational upper bound for the ground- state energy of two-dimensional antiferromagnetic Heisenberg model on a square lattice at arbitrary value of the anisotropy parameter using the two-dimensional generalization of Jordan-Wigner transformation. Our result can be considered as an upper bound for the perturbation theory series about the Ising