Relaxation and Localization in Interacting Quantum Maps

We quantise and study several versions of finite multibaker maps. Classically these are exactly solvable K-systems with known exponential decay to global equilibrium. This is an attempt to construct simple models of relaxation in quantum systems. The effect of symmetries and localization on quantum transport is discussed.Comment: 32 pages. LaTex file. 9 figures, not included. For figures send mail to first author at '[email protected]

Report of the QCD Tools Working Group

We report on the activities of the ``QCD Tools for heavy flavors and new physics searches'' working group of the Run II Workshop on QCD and Weak Bosons. The contributions cover the topics of improved parton showering and comparisons of Monte Carlo programs and resummation calculations, recent developments in Pythia, the methodology of measuring backgrounds to new physics searches, variable flavor number schemes for heavy quark electro-production, the underlying event in hard scattering processes, and the Monte Carlo MCFM for NLO processes.Comment: LaTeX, 47 pages, 41 figures, 10 tables, uses run2col.sty, to appear in the Proceedings of the Workshop on "QCD and Weak Boson Physics in Run II", Fermilab, March - November 199

Quantum Multibaker Maps: Extreme Quantum Regime

We introduce a family of models for quantum mechanical, one-dimensional random walks, called quantum multibaker maps (QMB). These are Weyl quantizations of the classical multibaker models previously considered by Gaspard, Tasaki and others. Depending on the properties of the phases parametrizing the quantization, we consider only two classes of the QMB maps: uniform and random. Uniform QMB maps are characterized by phases which are the same in every unit cell of the multibaker chain. Random QMB maps have phases that vary randomly from unit cell to unit cell. The eigenstates in the former case are extended while in the latter they are localized. In the uniform case and for large $\hbar$, analytic solutions can be obtained for the time dependent quantum states for periodic chains and for open chains with absorbing boundary conditions. Steady state solutions and the properties of the relaxation to a steady state for a uniform QMB chain in contact with ``particle'' reservoirs can also be described analytically. The analytical results are consistent with, and confirmed by, results obtained from numerical methods. We report here results for the deep quantum regime (large $\hbar$) of the uniform QMB, as well as some results for the random QMB. We leave the moderate and small $\hbar$ results as well as further consideration of the other versions of the QMB for further publications.Comment: 17 pages, referee's and editor's comments addresse

A Guide to Localized Frames and Applications to Galerkin-like Representations of Operators

This chapter offers a detailed survey on intrinsically localized frames and the corresponding matrix representation of operators. We re-investigate the properties of localized frames and the associated Banach spaces in full detail. We investigate the representation of operators using localized frames in a Galerkin-type scheme. We show how the boundedness and the invertibility of matrices and operators are linked and give some sufficient and necessary conditions for the boundedness of operators between the associated Banach spaces.Comment: 32 page

Bi-large Neutrino Mixing and Mass of the Lightest Neutrino from Third Generation Dominance in a Democratic Approach

We show that both small mixing in the quark sector and large mixing in the lepton sector can be obtained from a simple assumption of universality of Yukawa couplings and the right-handed neutrino Majorana mass matrix in leading order. We discuss conditions under which bi-large mixing in the lepton sector is achieved with a minimal amount of fine-tuning requirements for possible models. From knowledge of the solar and atmospheric mixing angles we determine the allowed values of sin \theta_{13}. If embedded into grand unified theories, the third generation Yukawa coupling unification is a generic feature while masses of the first two generations of charged fermions depend on small perturbations. In the neutrino sector, the heavier two neutrinos are model dependent, while the mass of the lightest neutrino in this approach does not depend on perturbations in the leading order. The right-handed neutrino mass scale can be identified with the GUT scale in which case the mass of the lightest neutrino is given as (m_{top}^2/M_{GUT}) sin^2 \theta_{23} sin^2 \theta_{12} in the limit sin \theta_{13} = 0. Discussing symmetries we make a connection with hierarchical models and show that the basis independent characteristic of this scenario is a strong dominance of the third generation right-handed neutrino, M_1, M_2 < 10^{-4} M_3, M_3 = M_{GUT}.Comment: typos correcte

Diagonalization of multicomponent wave equations with a Born-Oppenheimer example

A general method to decouple multicomponent linear wave equations is presented. First, the Weyl calculus is used to transform operator relations into relations between c-number valued matrices. Then it is shown that the symbol representing the wave operator can be diagonalized systematically up to arbitrary order in an appropriate expansion parameter. After transforming the symbols back to operators, the original problem is reduced to solving a set of linear uncoupled scalar wave equations. The procedure is exemplified for a particle with a Born-Oppenheimer-type Hamiltonian valid through second order in h. The resulting effective scalar Hamiltonians are seen to contain an additional velocity-dependent potential. This contribution has not been reported in recent studies investigating the adiabatic motion of a neutral particle moving in an inhomogeneous magnetic field. Finally, the relation of the general method to standard quantum-mechanical perturbation theory is discussed

h→μτh\to \mu\tau at Hadron Colliders

We study the observability for a lepton flavor-changing decay of a Higgs boson $h\to \mu\tau$ at hadron colliders. Flavor-changing couplings of a Higgs boson exist at tree level in models with multiple Higgs doublets. The $h\mu\tau$ coupling is particularly motivated by the favorable intepretation of $\nu_\mu-\nu_\tau$ oscillation. We find that at the Tevatron Run II the unique $\mu\tau$ signature could serve as the Higgs discovery channel, surpassing expectations for Higgs boson searches in the SM and in a large parameter region of the MSSM. The sensitivity will be greatly improved at the LHC, beyond the coverage at a muon collider Higgs factory.Comment: Version to appear in PR

Lentiviral Vector Delivery of Human Interleukin-7 (hIL-7) to Human Immune System (HIS) Mice Expands T Lymphocyte Populations

Genetically modified mice carrying engrafted human tissues provide useful models to study human cell biology in physiologically relevant contexts. However, there remain several obstacles limiting the compatibility of human cells within their mouse hosts. Among these is inadequate cross-reactvitiy between certain mouse cytokines and human cellular receptors, depriving the graft of important survival and growth signals. To circumvent this problem, we utilized a lentivirus-based delivery system to express physiologically relevant levels of human interleukin-7 (hIL-7) in Rag2-/-γc-/- mice following a single intravenous injection. hIL-7 promoted homeostatic proliferation of both adoptively transferred and endogenously generated T-cells in Rag2-/-γc-/- Human Immune System (HIS) mice. Interestingly, we found that hIL-7 increased T lymphocyte numbers in the spleens of HIV infected HIS mice without affecting viral load. Taken together, our study unveils a versatile approach to deliver human cytokines to HIS mice, to both improve engraftment and determine the impact of cytokines on human diseases

Enhancement of the Higgs pair production at LHC; the MSSM and extra dimension effects

The neutral Higgs pair production at the LHC is studied in the MSSM, the large extra dimensional (ADD) model and the Randall-Sundrum (RS) model, where the total cross section can be significantly enhanced compared to that in the SM. The $p_{_T}$, invariant mass and rapidity distributions of each model have been shown to be distinctive: The ADD model raises the $p_T$ and invariant mass distributions at high scales of $p_T$ and invariant mass; in the RS model resonant peaks appear after the SM contribution dies away; the SM and the MSSM distributions drop rapidly at those high scales; in the ADD and the RS models the rapidity distributions congregate more around the center. It is concluded that various distributions of the Higgs pair production at the LHC with restrictive kinematic cuts would provide one of the most robust signals for the extra dimensional effects.Comment: Revised version, 26 pages including 11 figures, ReVTe

Tevatron-for-LHC Report: Preparations for Discoveries

This is the "TeV4LHC" report of the "Physics Landscapes" Working Group, focused on facilitating the start-up of physics explorations at the LHC by using the experience gained at the Tevatron. We present experimental and theoretical results that can be employed to probe various scenarios for physics beyond the Standard Model.Comment: 222 pp., additional contribution added, typos/layout correcte