Research archive

arXiv papers from June 1994

The most recent 100 records published that month. Open any paper for its original abstract, citation metadata, related research, and reading tools.

  1. Soo-Jong REY

    In this talk I report calculable nonperturbative QCD effects to the inclusive semileptonic and radiative B-meson decay rates. Small instantons contribute to the Wilson coefficient functions at scales below $m_b$. It is found that the instantons give rise to a potentially large correction to the decay rate near the boundaries of the phase space for the semile

  2. George Jikia, Avto Tkabladze

    We present production rates of the two- and three-jet final states for the processes of massive $c\bar c/b\bar b$ quark production in circularly polarized photon-photon collisions, including QCD radiative corrections. Lowest order cross section, one-loop virtual correction and gluon emission correction are shown to be of the same order of magnitude for $b\ba

  3. M. A. van Eijck, Denjoe O'Connor, C. R. Stephens

    Contribution to the proceedings of the NATO workshop on the Electroweak Phase Transition and the Early Universe, Sintra, March 1994. To be published by Plenum Press.

  4. Jens Erler

    LEP determines $\sin^2 \theta_{\rm eff}$, by combining the various asymmetry measurements to be $0.2321 \pm 0.0005$. On the other hand, the left-right asymmetry as measured at SLC corresponds to \seff = $0.2292 \pm 0.0010$. I will discuss the possibilities of this being i) a statistical fluctuation, ii) a hint for New Physics or iii) an experimental discrepa

  5. A. Djouadi

    I summarize the prospects for discovering Higgs bosons at future $pp$ and $\ee$ colliders both in the Standard Model and its Minimal Supersymmetric extension.

  6. A. Djouadi, P. Gambino

    At proton colliders, Higgs particles are dominantly produced in the gluon--gluon fusion mechanism. The Higgs--gluons coupling is mediated by heavy quark loops, and the process can serve to count the number of heavy strongly interacting particles whose masses are generated by the Higgs mechanism. We present the two--loop leading electroweak radiative correcti

  7. A. Djouadi, P. Gambino

    We present the QCD corrections to Higgs boson self-energies for arbitrary momentum transfer and for different internal quark masses, to treat the case of CP--even, CP--odd and charged Higgs bosons which appear in extensions of the Standard Model scalar sector. Using Ward Identities, we then relate these results obtained by directly evaluating the relevant tw

  8. A. Djouadi

    The prospects for discovering Higgs particles and studying their fundamental properties at future high-energy electron-positron and hadron colliders are reviewed. Both the Standard Model Higgs boson and the Higgs particles of its minimal supersymmetric extension are discussed. We update various results by taking into account the new value of the top quark ma

  9. Ka Lok Ng, Kin-Wang Ng

    We discuss the contribution of gravitational wave to the cosmic microwave background radiation (CMBR) anisotropy and polarization. It is found that the large-scale polarization of CMBR is less than 1\% for a standard recombination universe. The effect of matter reionization will enhance the CMBR polarization to a 10\% level. We have computed the CMBR polariz

  10. J. Bagger, A. Galperin

    We use nonlinear realizations to describe the spontaneous breaking of $N=2$ supersymmetry to $N=1$ in four dimensions. We identify the Goldstone multiplet with an $N=1$ chiral superfield, and show that chiral $N=1$ matter is consistent with the partially broken $N=2$ supersymmetry. We find that the chiral matter can be in any representation of the gauge grou

  11. Ladislav Hlavaty, Anjan Kundu

    A scheme suitable for describing quantum nonultralocal models including supersymmetric ones is proposed. Braided algebras are generalised to be used through Baxterisation for constructing braided quantum Yang--Baxter equations. Supersymmetric and some known nonultralocal models are derived in the framework of the present approach. As further applications of

  12. J. C. Brunelli, A. Das

    We construct the most general supersymmetric two boson system that is integrable. We obtain the Lax operator and the nonstandard Lax representation for this system. We show that, under appropriate redefinition of variables, this reduces to the supersymmetric nonlinear Schr\"odinger equation without any arbitrary parameter which is known to be integrable. We

  13. E. J. Copeland, Amitabha Lahiri, David Wands

    We give the general analytic solutions derived from the low energy string effective action for four dimensional Friedmann-Robertson-Walker models with dilaton and antisymmetric tensor field, considering both long and short wavelength modes of the $H$-field. The presence of a homogeneous $H$-field significantly modifies the evolution of the scale factor and d

  14. G. Amelino-Camelia, D. Bak

    We argue that the results obtained using the quantum mechanical method of self-adjoint extension of the Schr\"odinger Hamiltonian can also be derived using Feynman perturbation theory in the investigation of the corresponding non-relativistic field theories. We show that this is indeed what happens in the study of an anyon system, and, in doing so, we establ

  15. G. Amelino-Camelia

    In bosonic end perturbative calculations for quantum mechanical anyon systems a regularization and renormalization procedure, analogous to those used in field theory, is necessary. I examine the reliability and the physical interpretation of the most commonly used bosonic end regularization procedures. I then use the regularization procedure with the most tr

  16. Enrico Arbarello, Maurizio Cornalba

    Based on the combinatorial description of the moduli spaces of curves provided by Strebel differentials, Witten and Kontsevich have introduced combinatorial cohomology classes $W_{(m_0,m_1,m_2,\dots),n}$, and conjectured that these can be expressed in terms of Mumford-Morita-Miller classes. It is argued that this link should be provided by a theorem of Di Fr

  17. Gautam Bhattacharyya, Gustavo C. Branco, Debajyoti Choudhury

    We point out that $R \equiv Br(b\rightarrow d \gamma)/Br(b\rightarrow s \gamma)$ is a sensitive probe of possible violation of CKM unitarity. We compute $R$ in a minimal extension of the Standard Model containing an additional isosinglet charge ($-1/3$) quark, which leads to a deviation from CKM unitarity.

  18. J. O. White, R. Buhleier, S. D. Brorson, I. E. Trofimov

    The complex transmission of Y_{1-x}Pr_xBa_2Cu_3O_7 single crystal thin films has been measured in the range 0.2-1.0 THz using time domain spectroscopy. The complex conductivity is calculated without using a Kramers-Kronig analysis. All of the superconducting samples show a peak in $\sigma_1(T)$ below $T_c$. The underdoped samples show a deviation from $1/(\a

  19. Ashok Das, Marcelo Hott

    We show both in 1+1 and 3+1 dimensions that, contrary to the recent suggestions, the contribution of the fermion loop to the polarization tensor is manifestly transverse at finite temperature. Some subtleties associated with the Ward identities at finite temperature are also pointed out.

  20. J. L. F. Barbon

    We discuss the semiclassical approximation to the level density of (super) strings propagating in non-compact coset manifolds $G/H$. We show that the WKB ansatz agrees with heuristic red-shift arguments with respect to the ``exact" sigma model metric, up to some deviations from minimal coupling, parametrized by the dilaton. This approximation is used to stud

  21. Yang Xing

    The complex Monge-Amp\`ere operator $(dd^c)^n$ is an important tool in complex analysis. It would be interesting to find the right notion of convergence $u_j\to u$ such that $(dd^cu_j)^n\to (dd^cu)^n$ in the weak topology. In this paper, using the $C_{n-1}$-capacity, we give a sufficient condition of the weak convergence $(dd^cu_j)^n\to (dd^cu)^n$. We also s

  22. J. Lopez, D. Nanopoulos, X. Wang, A. Zichichi

    We perform a detailed study of the constraints from $b\to s\gamma$ on a large class of supergravity models, including generic four-parameter supergravity models, the minimal $SU(5)$ supergravity model, and $SU(5)\times U(1)$ supergravity. For each point in the parameter spaces of these models we obtain a range of $B(b\to s\gamma)$ values which should conserv

  23. Masatoshi Sato, Shigeaki Yahikozawa

    We present a ``topological'' formulation of arbitrarily shaped vortex strings in four dimensional field theory. By using a large Higgs mass expansion, we then evaluate the effective action of the closed Abrikosov-Nielsen-Olesen vortex string. It is shown that the effective action contains the Nambu-Goto term and an extrinsic curvature squared term with negat

  24. Johan Bijnens

    A short introduction to quark models with four fermion terms and their predictions for the parameters of low-energy effective Lagrangians is given. Special attention is paid to predictions that are as general as possible. Contribution to the Second DAPHNE Physics Handbook, eds. L. Maiani, G. Pancheri and N. Paver.

  25. Paul Kirk, Eric Klassen

    We show how to compute the spectral flow of the odd signature operator $\pm *d_{a_t}-d_{a_t}*$ along an analytic path of flat connections $a_t$ on a bundle over a closed odd-dimensional manifold in terms of Massey products in the DGLA of bundle-valued differential forms. To obtain this information, we set up a sequence of cochain complexes $\{\calg^*_n,\delt

  26. V. G. J. Stoks, R. A. M. Klomp, C. P. F. Terheggen, J. J. de Swart

    We present an updated version (Nijm93) of the Nijmegen soft-core potential, which gives a much better description of the np data than the older version (Nijm78). The chi^2 per datum is 1.87. The configuration-space and momentum-space versions of this potential are exactly equivalent; a unique feature among meson-theoretical potentials. We also present three

  27. M. Ikehara, N. Ishibashi, H. kawai, T. Mogami

    We construct the string field Hamiltonian for $c=1-\frac{6}{m(m+1)}$ string theory in the temporal gauge. In order to do so, we first examine the Schwinger-Dyson equations of the matrix chain models and propose the continuum version of them. Results of boundary conformal field theory are useful in making a connection between the discrete and continuum pictur

  28. E. Alvarez, L. Alvarez-Gaume, Y. Lozano

    We show that Buscher's abelian duality transformation rules can be recovered in a very simple way by performing a canonical transformation first suggested by Giveon, Rabinovici and Veneziano. We explore the properties of this transformation, and also discuss some aspects of non-abelian duality.

  29. J. Koplik, S. Redner, E. J. Hinch

    The dynamics of passive Brownian tracer particles in steady two-dimensional potential flows between sources and sinks is investigated. The first-passage probability, $p(t)$, exhibits power-law decay with a velocity-dependent exponent in radial flow and an order-dependent exponent in multipolar flows. For the latter, there also occur diffusive ``echo'' should

  30. I. Ya. Aref'eva, G. E. Arutyunov, P. B. Medvedev

    The aim of this lecture is to give a pedagogical explanation of the notion of a Poisson Lie structure on the external algebra of a Poisson Lie group which was introduced in our previous papers. Using this notion as a guide we construct quantum external algebras on $SL_q(N)$ with proper (classical) dimension.

  31. A. Ghosh, P. Mitra

    The area formula for entropy is extended to the case of a dilatonic black hole. The entropy of a scalar field in the background of such a black hole is calculated semiclassically. The area and cutoff dependences are normal {\it except in the extremal case}, where the area is zero but the entropy nonzero.

  32. Sherman Frankel, William Frati, Niels R. Walet

    We make detailed comparisons between the measured $Q^2$ dependency of nuclear transparency in quasifree electron scattering and theoretical predictions based on Glauber theory. We also describe a theory-free method to extract $T$ from data.

  33. Anu Venugopalan

    The effect of decoherence is analysed for a free particle, interacting with an environment via a dissipative coupling. The interaction between the particle and the environment occurs by a coupling of the position operator of the particle with the environmental degrees of freedom. By examining the exact solution of the density matrix equation one finds that t

  34. A. Jadczyk

    The paper consists of two parts. In the first part Schroedinger's equation for a charged quantum particle in a Galilei-Newton curved space-time is derived in a fully geometrical way. Gravitational and electromagnetic fields are coded into space metric and space-time connection. The fundamental geometrical object is a quantum connection in a Hermitian line bu

  35. Peter W. Michor

    A section of a Riemannian $G$-manifold $M$ is a closed submanifold $\Sigma$ which meets each orbit orthogonally. It is shown that the algebra of $G$-invariant differential forms on $M$ which are horizontal in the sense that they kill every vector which is tangent to some orbit, is isomorphic to the algebra of those differential forms on $\Sigma$ which are in

  36. Peter W. Michor, Cornelia Vizman

    Some groups of real analytic diffeomorphism act n-transitively for each finite n.

  37. W. Melnitchouk, W. Weise

    We investigate deep inelastic lepton scattering from the nucleon within a constituent quark picture, in which the internal structure of constituent quarks is modeled by meson and diquark dressing. In a covariant framework this structure leads to a breakdown of the factorization necessary for a convolution formulation. We perform our analysis in time-ordered

  38. R. Blumenhagen, W. Eholzer, A. Honecker, K. Hornfeck

    We construct several quantum coset W-algebras, e.g. sl(2,R)/U(1) and sl(2,R)+sl(2,R) / sl(2,R), and argue that they are finitely nonfreely generated. Furthermore, we discuss in detail their role as unifying W-algebras of Casimir W-algebras. We show that it is possible to give coset realizations of various types of unifying W-algebras, e.g. the diagonal coset

  39. Arvind Borde

    This paper clarifies some aspects of Lorentzian topology change, and it extends to a wider class of spacetimes previous results of Geroch and Tipler that show that topology change is only to be had at a price. The scenarios studied here are ones in which an initial spacelike surface is joined by a connected ``interpolating spacetime'' to a final spacelike su

  40. Hitoshi Murayama, D. B. Kaplan

    The proton decay modes $p\to K^0 e^+$ and $p\to K^0 \mu^+$ may be visible in certain supersymmetric theories, and if seen would provide evidence for new flavor physics at extremely short distances. These decay modes can arise from the dimension five operator $(Q_1Q_1Q_2L_{1,2})$, where $Q_i$ and $L_i$ are ${i^{th}}$ generation quark and lepton superfields re

  41. Milan PALUS

    A method for testing nonlinearity in time series is described based on information-theoretic functionals -- redundancies, linear and nonlinear forms of which allow either qualitative, or, after incorporating the surrogate data technique, quantitative evaluation of dynamical properties of scrutinized data. An interplay of quantitative and qualitative testing

  42. A. M. Shirokov, Yu. F. Smirnov, S. A. Zaytsev

    We show that a quantum system with nonlocal interaction can have bound states of unusual type (isolated states (IS)). IS is a bound state that do not generate a $S$-matrix pole. IS can have positive as well as negative energy and can be treated as a generalization of bound states embedded in continuum on the case of discrete spectrum states. Formation of IS

  43. Rafe Mazzeo, Daniel Pollack, Karen Uhlenbeck

    Complete, conformally flat metrics of constant positive scalar curvature on the complement of $k$ points in the $n$-sphere, $k \ge 2$, $n \ge 3$, were constructed by R\. Schoen [S2]. We consider the problem of determining the moduli space of all such metrics. All such metrics are asymptotically periodic, and we develop the linear analysis necessary to unders

  44. Mourad E. H. Ismail, Mizan Rahman

    We find the raising and lowering operators for orthogonal polynomials on the unit circle introduced by Szeg\H{o} and for their four parameter generalization to ${}_4\phi_3$ biorthogonal rational functions on the unit circle.

  45. N. Asmar, B. Kelly, Stephen J. Montgomery-Smith

    We introduce the notion of an ACF space, that is, a space for which a generalized version of M. Riesz's theorem for conjugate functions with values in the Banach space is bounded. We use transference to prove that spaces for which the Hilbert transform is bounded, i\.e\. $X\in\text{HT}$, are ACF spaces. We then show that Bourgain's proof of $X\in\text{HT}\im

  46. A. A. Aligia, L. Arrachea

    We obtain the exact solution of a general Hubbard chain with kinetic energy $t$, bond-charge interaction $X$ and on-site interaction $U$ with the only restriction $t = X$. At zero temperature and half filling, the model exhibits a Mott transition at $U = 4t$. In the metallic phase and near half filling, superconducting states are part of the degenerate groun

  47. C. D. Batista, A. A. Aligia

    We evaluate numerically several superconducting correlation functions in a generalized $t-J$ model derived for hole-doped CuO$_2$ planes. The model includes a three-site term $t''$ similar to that obtained in the large $U$ limit of the Hubbard model but of opposite sign for realistic O-O hopping. For realistic parameters we obtain strong evidence of

  48. E. Abdalla, M. C. B. Abdalla

    We consider the quantum Hall effect in terms of an effective field theory formulation of the edge states, providing a natural common framework for the fractional and integral effects.

  49. Michael McGuigan

    An accelerating observer sees a thermal bath of radiation at the Hawking temperature which is proportional to the acceleration. Also, in string theory there is a Hagedorn temperature beyond which one cannot go without an infinite amount of energy. Several authors have shown that in the context of Hawking radiation a limiting temperature for string theory lea

  50. J. Richard Bond

    In inflation cosmologies, cosmic structure develops through the gravitational instability of the inevitable quantum noise in primordial scalar fields. I show how the acceleration of the universe defines the shape of the primordial spectrum of gravitational metric and scalar field fluctuations. I assess how we can determine the shape and overall amplitude ove

  51. Richard W. Haymaker, Vandana Singh, Yingcai Peng, Jacek Wosiek

    We report detailed calculations of the profiles of energy and action densities in the quark-antiquark string in SU(2) lattice gauge theory.

  52. H. Monien, T. M. Rice

    There is strong experimental evidence for substantial antiferromagnetic coupling between the CuO$_2$ planes of the bilayers in YBCO compounds. The acoustic mode of the spin excitation spectrum has been measured but the optic mode has not been observed. Theoretical estimates suggest values for the antiferromagnetic interplane coupling as large as 10 meV. It h

  53. Yong-Zhong Qian, George M. Fuller

    The revised version of the widely circulated preprint ``Neutrino Flavor Evolution Near A Supernova's Core'' by J. Pantaleone (astro-ph 9405008 on the Bulletin Board, Indiana University preprint IUHET-276) is wrong. It contains two errors which lead to incorrect conclusions regarding neutrino flavor transformation in the supernova environment. In this short n

  54. D. Boyanovsky, David E. Brahm, R. Holman, Da-Shin Lee

    We address the problem of how to incorporate quantum effects into the calculation of finite-temperature decay rates for a metastable state of a quantum field theory. To do this, we consider the Gross-Neveu model with an explicit chiral symmetry breaking term, which allows for a metastable state. This theory can be shown to have a "critical bubble" which is a

  55. Yong-Zhong Qian, George M. Fuller

    We examine matter-enhanced neutrino flavor transformation ($\nu_{\tau(\mu)}\rightleftharpoons\nu_e$) in the region above the neutrino sphere in Type II supernovae. Our treatment explicitly includes contributions to the neutrino-propagation Hamiltonian from neutrino-neutrino forward scattering. A proper inclusion of these contributions shows that they have a

  56. F. M"uller-Hoissen

    The central structure in various versions of noncommutative geometry is a differential calculus on an associative algebra. This is an analogue of the calculus of differential forms on a manifold. In this short review we collect examples of differential calculi on commutative algebras (which can be regarded as algebras of functions on some topological space).

  57. Kenneth Halpern, Kerson Huang

    We search for alternatives to the trivial $\phi^4$ field theory by including arbitrary powers of the self-coupling. Such theories are renormalizable when the natural cutoff dependencies of the coupling constants are taken into account. We find a continuum of fixed points, which includes the well-known Gaussian fixed point. The fixed point density has a maxim

  58. M. J. Duff, R. Minasian

    After simultaneous compactification of spacetime and worldvolume on $K3$, the $D=10$ heterotic fivebrane with gauge group $SO(32)$ behaves like a $D=6$ heterotic string with gauge group $SO(28) \times SU(2)$, but with Kac--Moody levels different from those of the fundamental string. Thus the string/fivebrane duality conjecture in $D=10$ gets replaced by a st

  59. A. O. Bazarko

    We present the first next-to-leading-order QCD analysis of neutrino charm production, using a sample of 6090 $\nu_\mu$- and $\bar\nu_\mu$-induced opposite-sign dimuon events observed in the CCFR detector at the Fermilab Tevatron. We find that the nucleon strange quark content is suppressed with respect to the non-strange sea quarks by a factor $\kappa = 0.47

  60. Michael Wolf

    We give a new proof of the existence (\cite{HM}, \cite{Ren}) of a Jenkins-Strebel differential $\Phi$ on a Riemann surface $\SR$ with prescribed heights of cylinders by considering the harmonic map from $\SR$ to the leaf space of the vertical foliation of $\Phi$, thought of as a Riemannian graph. The novelty of the argument is that it is essentially Riemanni

  61. A. Yu. Alekseev, L. D. Faddeev

    It is known that the involution corresponding to the compact form is incompatible with comultiplication for quantum groups at $|q|=1$. In this paper we consider the quantum algebra of functions on the deformed space $T^{*}G_{q}$ which includes both the quantum group and the quantum universal enveloping algebra as subalgebras. For this extended object we cons

  62. C. R. Muenz, J. Resag, B. C. Metsch, H. R. Petry

    We present a covariant scheme to calculate mesonic transitions in the framework of the Salpeter equation for $q\bar{q}$-states. The full Bethe Salpeter amplitudes are reconstructed from equal time amplitudes which were obtained in a previous paper\cite{Mue} by solving the Salpeter equation for a confining plus an instanton induced interaction. This method is

  63. C. Greub, H. Simma, D. Wyler

    We calculate CP-violating rate asymmetries in the rare radiative decays $B^\pm\rightarrow K^{\ast\pm} \gamma$ and $B^\pm\rightarrow \rho^\pm \gamma$. They arise because of the interference between leading-order penguin amplitudes and one-gluon corrections with absorptive phases, and provide unambiguous evidence for direct CP violation. Complementing earlier

  64. L. S. Levitov, A. V. Shytov, A. Yu. Yakovets

    Breaking of an atomic chain under stress is a collective many-particle tunneling phenomenon. We study classical dynamics in imaginary time by using conformal mapping technique, and derive an analytic formula for the probability of breaking. The result covers a broad temperature interval and interpolates between two regimes: tunneling and thermal activation.

  65. R. Alkofer, H. Reinhardt, J. Schlienz, H. Weigel

    The role of chiral transformations in effective theories modeling Quantum Chromo Dynamics is reviewed. In the context of the Nambu--Jona--Lasinio model the hidden gauge and massive Yang--Mills approaches to vector mesons are demonstrated to be linked by a special chiral transformation which removes the chiral field from the scalar--pseudoscalar sector. The c

  66. A. Babichenko

    Perturbations of $WD_n$ and $W_3$ conformal theories which generalize the $(1,2)$ perturbations of conformal minimal models are shown to be integrable by counting argument. $A_{2n-1,q}^{(2)}$ and $D_{4,q}^ {(3)}$ symmetries of corresponding S-matrices are conjectured and proved by explicit construction of conserved nonlocal charges in the $WD_3$ case with th

  67. Kazunori Itakura, Koichi Ohta

    We reexamine a unitary-transformation method of extracting a physical Hamiltonian from a gauge field theory after quantizing all degrees of freedom including redundant variables. We show that this {\it quantum Hamiltonian reduction} method suffers from crucial modifications arising from regularization of composite operators. We assess the effects of regulari

  68. V. A. Bednyakov, W. de Boer, S. G. Kovalenko

    The top quark mass values from the CDF Collaboration and the precision electroweak data at LEP combined with the bottom mass value allow to establish bounds on the parameter tan beta in the minimal supersymmetric standard model (MSSM) independent of the soft supersymmetry breaking parameters. We find: 0.96 < tan beta < 52.2 at the 95 % C.L., which is mostly

  69. Daniel Rohrlich, Yakir Aharonov, Sandu Popescu, Lev Vaidman

    An analysis of errors in measurement yields new insight into classically forbidden quantum processes. In addition to "physical" values, a realistic measurement can yield "unphysical" values; we show that in {\it sequences} of measurements, the "unphysical" values can form a consistent pattern. An experiment to isolate a particle in a classically forbidden re

  70. S. Iso, S. J. Rey

    \noindent Using hydrodynamic collective field theory approach we show that one-particle density matrix of the $\nu=1/m$ fractional quantum Hall edge state interpolates between chiral Luttinger liquid behavior $\langle \psi^{\dagger}(r) \psi(0) \rangle \sim r^{-m} $ and Calogero-Sutherland model behavior $\langle \psi^{\dagger}(r) \psi(0) \rangle \sim r^{-(m+

  71. E. Elizalde, S. D. Odintsov

    A new theory for the conformal factor in R$^2$-gravity is developed. The infrared phase of this theory, which follows from the one-loop renormalization group equations for the whole quantum R$^2$-gravity theory is described. The one-loop effective potential for the conformal factor is found explicitly and a mechanism for inducing Einstein gravity at the mini

  72. Gerard Clement

    We discuss the reduction of gravitating Chern-Simons electrodynamics with two commuting Killing vectors to a dynamical problem with four degrees of freedom, and present regular particle-like solutions.

  73. Denis Juriev

    Stochastic properties of the long time behavior of a continuously observed (and interactively controlled) quantum--field top are investigated mathematically. Applications to interactively controlled stochastic computerographical dynamic systems are discussed.

  74. G. Rietveld, S. J. Collocot, D. van der Marel

    Using X-ray photoelectron spectroscopy, a systematic study is performed of the doping dependence of the chemical potential $\mu$ in two systems of (Bi,Pb)$_2$Sr$_2$Ca$_2$Cu$_3$O$_{10+\delta}$. The doping is varied by changing the O content of the sample. The measured shifts of the chemical potential are compared with present models for the doping behaviour o

  75. S. P. Brumby, G. C. Joshi

    The complex unit appearing in the equations of quantum mechanics is generalised to a quaternionic structure on spacetime, leading to the consideration of complex quantum mechanical particles whose dynamical behaviour is governed by inhomogeneous Dirac and Schr\"{o}dinger equations. Mixing of hyper-complex components of wavefunctions occurs through their inte

  76. Oscar F. Hernandez, David London

    We present the current wisdom regarding the measurement of the CP-violating phases of the CKM unitarity triangle in $B$-meson decays. After an introduction to the SM picture of CP violation, we review direct and indirect CP violation, the role of penguins and isospin analysis, and $B\to DK$ decays. We also discuss recent work on how to use SU(3) flavor symme

  77. J. Hisano, T. Moroi, K. Tobe, T. Yanagida

    We construct a missing-partner model for supersymmetric SU(5) GUT assuming the Peccei-Quinn symmetry, in which the SU(5) gauge coupling constant remains in the perturbative regime below the gravitational scale $\sim2.4\times 10^{18}\GEV$. The Peccei-Quinn symmetry suppresses the dangerous dimension-five operators for the nucleon decay much below the limit fr

  78. Yi-Zhi Huang

    We describe a natural structure of an abelian intertwining algebra (in the sense of Dong and Lepowsky) on the direct sum of the untwisted vertex operator algebra constructed {}from the Leech lattice and its (unique) irreducible twisted module. When restricting ourselves to the moonshine module, we obtain a new and conceptual proof that the moonshine module h

  79. Thomas Appelquist, Guo-Hong Wu

    We estimate the CP-violating $WW\gamma$ and $WWZ$ anomalous form factors, arising from CP-violating interactions in extended technicolor theories, and discuss their future experimental detectability. The electric dipole moment of the $W$ boson is found to be as large as ${\cal O}(10^{-21}) \; \mbox{$e$ cm}$. We connect the CP-odd $WW\gamma$ and $WWZ$ couplin

  80. Sergei Khoroshkin, Valeriy N. Tolstoy

    Studying the algebraic structure of the double ${\cal D}Y(g)$ of the yangian $Y(g)$ we present the triangular decomposition of ${\cal D}Y(g)$ and a factorization for the canonical pairing of the yangian with its dual inside ${\cal D}Y(g)$. As a consequence we obtain an explicit formula for the universal R-matrix $R$ of ${\cal D}Y(g)$ and demonstrate how it w

  81. Y-h. Taguchi, Hideki Takayasu

    Distribution functions of relative velocities among particles in a vibrated bed of powder are studied both numerically and theoretically. In the solid phase where granular particles remain near their local stable states, the probability distribution is Gaussian. On the other hand, in the fluidized phase, where the particles can exchange their positions, the

  82. Anne de Médicis, Dennis W. Stanton

    The linearization coefficients for a set of orthogonal polynomials are given explicitly as a weighted sum of combinatorial objects. Positivity theorems of Askey and Szwarc are corollaries of these expansions.

  83. Laura M. Chihara, Dennis W. Stanton

    {Let ${\Cal X}$ be a self-dual P-polynomial association scheme. Then there are at most 12 diagonal matrices $T$ such that $(PT)^3=I$. Moreover, all of the solutions for the classical infinite families of such schemes (including the Hamming scheme) are classified.

  84. C. C. A. Günther, P. A. Rikvold, M. A. Novotny

    Applying a numerical transfer-matrix formalism, we obtain complex-valued constrained free energies for the two-dimensional square-lattice nearest-neighbor Ising ferromagnet below its critical temperature and in an external magnetic field. In particular, we study the imaginary part of the constrained free-energy branch that corresponds to the metastable phase

  85. Manuel Drees

    I discuss the minijet contribution to total photoproduction and photon--photon cross sections. While minijets with $p_T$ around 2 GeV have recently been observed directly in \gamgam\ experiments, the total \gamp\ cross section measured at HERA is in excellent agreement with predictions based on purely soft physics. Due to the large number of free parameters,

  86. J. Zanelli

    It is pointed out that the action recently proposed by Ba\~nados et al. for gravitation in odd dimensions higher (and lower) than four, provides a natural quantization for the gravitational constant. These theories possess no dimensionful parameters and hence they may be power counting renormalizable.

  87. Brian W. Bush, J. Rayford Nix

    We discuss the production of particles in relativistic heavy-ion collisions through the mechanism of massive bremsstrahlung, in which massive mesons are emitted during rapid nucleon acceleration. This mechanism is described within the framework of classical hadrodynamics for extended nucleons, corresponding to nucleons of finite size interacting with massive

  88. Lay Nam Chang, Chopin Soo

    In this paper, we examine the coupling of matter fields to gravity within the framework of the Standard Model of particle physics. The coupling is described in terms of Weyl fermions of a definite chirality, and employs only (anti)self-dual or left-handed spin connection fields. It is known from the work of Ashtekar and others that such fields can furnish a

  89. Brian W. Bush, J. Rayford Nix

    We discuss a new approach to ultrarelativistic heavy-ion collisions based on classical hadrodynamics for extended nucleons, corresponding to nucleons of finite size interacting with massive meson fields. This new theory provides a natural covariant microscopic approach that includes automatically spacetime nonlocality and retardation, nonequilibrium phenomen

  90. D. Caenepeel, M. Leblanc

    We present the effective potential for nonrelativistic matter coupled to non-Abelian Chern-Simons gauge fields. We perform the calculation using a functional method in constant background fields to satisfy Gauss's law and to simplify the computation. Both the quantum gauge and matter fields are integrated over. The gauge fixing is achieved with an $R_\xi$-ga

  91. J. A. de Azcárraga, F. Rodenas

    We wish to report here on a recent approach to the non-commutative calculus on $q$-Minkowski space which is based on the reflection equations with no spectral parameter. These are considered as the expression of the invariance (under the coaction of the $q$-Lorentz group) of the commutation properties which define the different $q$-Minkowski algebras. This a

  92. M. S. Berger, M. S. Chanowitz

    We investigate the possibility of observing strong interactions of longitudinally polarized weak vector bosons in the process $\gamma \gamma \to ZZ$ at a photon linear collider. We make use of polarization of the photon beams and cuts on the decay products of the $Z$ bosons to enhance the signal relative to the background of transversely polarized $ZZ$ pairs

  93. G. Juettner, M. Karowski

    The $sl_q(2)$-quantum group invariant spin 1/2 XXZ-Heisenberg model with open boundary conditions is investigated by means of the Bethe ansatz. As is well known, quantum groups for $q$ equal to a root of unity possess a finite number of ``good'' representations with non-zero q-dimension and ``bad'' ones with vanishing q-dimension. Correspondingly, the state

  94. Hai-sheng Li

    We give an analogue for vertex operator algebras and superalgebras of the notion of endomorphism ring of a vector space by means of a notion of ``local system of vertex operators'' for a (super) vector space. We first prove that any local system of vertex operators on a (super) vector space $M$ has a natural vertex (super)algebra structure with $M$ as a modu

  95. Subhendra Mohanty

    We consider the low energy effective chiral theory of QCD mesons and the electroweak Goldstone bosons. In this effective theory the pion sector contributes to the gauge boson masses and the Yukawa couplings of the fermions. Consequently the Yukawa sector of quarks and leptons can have a $SU(2)_L\times U(1)_Y\times U(1)_A$ global symmetry even with nonvanishi

  96. Saul Youssef

    Bayesian complex probability theory is shown to be consistent with Bell's theorem and with other recent limitations on local realistic theories which agree with the predictions of quantum mechanics.

  97. M. Jeżabek

    Top quark studies at future $e^+e^-$ colliders are considered. Two issues are discussed: {a --}Some results are presented on the decays of top quarks. Energy distributions of charged leptons and neutrinos in $t\to bW\to be^+\nu$ and jets in $t\to bW\to b\bar du$ decays are sensitive to the structure of $tbW$ vertex. Distributions of charged leptons from top

  98. J. S. F. Chan, K. C. K. Chan, R. B. Mann

    The phenomenon of mass inflation is shown to occur for a rotating black hole. We demonstrate this feature in $(2+1)$ dimensions by extending the charged spinning BTZ black hole to Vaidya form. We find that the mass function diverges in a manner quantitatively similar to its static counterparts in $(3+1)$, $(2+1)$ and $(1+1)$ dimensions.

  99. Ana Lopez, Eduardo Fradkin

    We generalize the fermion Chern-Simons theory for the Fractional Hall Effect (FQHE) which we developed before, to the case of bilayer systems. We study the complete dynamic response of these systems and predict the experimentally accessible optical properties. In general, for the so called $(m, m, n)$ states, we find that the spectrum of collective excitatio

  100. Miles Osborne, Derek Bridge

    This paper describes a grammar learning system that combines model-based and data-driven learning within a single framework. Our results from learning grammars using the Spoken English Corpus (SEC) suggest that combined model-based and data-driven learning can produce a more plausible grammar than is the case when using either learning style isolation.