Triangle Analysis Research Articles

Charmless two-body B-meson decays in QCD

The coming years will witness tremendous progress at the ''high energy frontier'' accomplished primarily at the LHC. Important advances are also expected at the ''high precision frontier'' through the improved B_s-physics experiments at the Tevatr on and in particular LHCb at CERN. After summarizing the status of various tensions in the present Unitarity Triangle (UT) analyses, we consider a number of Supersymmetric models showing their capability to solve these tensions. Moreover, we show how the characteristic patterns of correlations among flavour observables allow to distinguish between these different SUSY scenarios. We propose a ''DNA-Flavour Test'' of NP models, with the aim of showing a tool to distinguish between these NP scenarios, once a dditional data on flavour changing processes become available.

Unitarity Triangle Analysis: An Update

We present the update of the Unitarity Triangle analysis performed by the UTfit Collaboration within the Standard Model and beyond. Within the Standard Model, we find an overall consistency among the constraints, with some tension between the fit prediction and the experimental measurement of BR ( B → τ ν ) , sin 2 β and e K . Generalising the analysis beyond the Standard Model, we allow for New Physics effects in all Δ F = 2 processes simultanously. We obtain constraints on the parameters of the Cabibbo-Kobayashi-Maskawa matrix together with the New Physics ones. We find that a deviation from the Standard Model at the 3.1σ level in the B s - B ¯ s mixing phase is confirmed by the present update, which includes the new DO result on the dimuon charge asymmetry. However the new CDF measurement of ϕ s is not included yet as the experimental likelihood is not publicly available.

Lattice QCD inputs to the CKM unitarity triangle analysis

We perform a global fit to the CKM unitarity triangle using the latest experimental and theoretical constraints. Our emphasis is on the hadronic weak matrix elements that enter the analysis, which must be computed using lattice QCD or other nonperturbative methods. Realistic lattice QCD calculations which include the effects of the dynamical up, down, and strange quarks are now available for all of the standard inputs to the global fit. We therefore present lattice averages for all of the necessary hadronic weak matrix elements. We attempt to account for correlations between lattice QCD results in a reasonable but conservative manner: whenever there are reasons to believe that an error is correlated between two lattice calculations, we take the degree of correlation to be 100%. These averages are suitable for use as inputs both in the global CKM unitarity triangle fit and other phenomenological analyses. In order to illustrate the impact of the lattice averages, we make Standard Model predictions for the parameters BK, |Vcb|, and |Vub|/|Vcb|. We find a (2-3) sigma tension in the unitarity triangle, depending upon whether we use the inclusive or exclusive determination of |Vcb|. If we interpret the tension as a sign of new physics in either neutral kaon or B mixing, we find that the scenario with new physics in kaon-mixing is preferred by present data.

The Futures Studies Toolbox and iPod Touch: Digitally Enabled Futures Images for the Japanese University 2020 Project

With a volatile economy and perceived indeterminate futures, Japanese companies are being forced by circumstances to change the way they recruit university graduates. One particular recruitment strategy currently being promoted at companies is to ask applicants to present a future strategy for the company. Unfortunately, Japanese universities are not preparing students to carefully analyse and strategise perceptions of the future leaving students poorly equipped to conceptualise alternative future possibilities and dangers. Given this background, one Multimedia Communication course at a techno- logy university in Japan adopted a Futures Studies & Thinking approach. The aim was to provide Complex Systems students (n=79) with a theory driven Futures Toolbox to design and present digitally enabled futures images (DEFI) of their university. The 15-week, 45-hour core course was split into explicitly teaching a Futures Studies Toolbox which included the Futures Triangle Analysis (FTA), scenario building, SWOT analysis, backcasting and Lasswells’ Communication Formula, in conjunction with practical multimedia skills such as movie editing and enhanced Podcast development. The challenge was how to communicate new ideas, derived from strategically applying the Futures Toolbox, in a creative, innovative way. Student teams were provided with an iPod Touch. Two iPod Touch applications in particular were used to develop the presentations: Strip Designer and StoryKit. These linked to students’ previously created photos and Podcasts synchronized on each iPod Touch. The students added text and recorded voice-overs to support their futures images. The originality of this paper resides firstly in the synergies produced by combining Futures Studies as praxis with the creation of digitally enabled futures images (DEFI), and secondly in the critical and self-reflexive nature of the unit of analysis: the Future University itself, whose very name, and cultural contexts, have not been critically examined before by its students.

Ethics and the Tax Profession: Restoring the Public Interest Focus

ABSTRACT: Tax practice is an integral component of the public accounting profession. Although accountancy as a profession embraces a strong public interest notion, there is an inevitable tension in tax practice between serving the client and maintaining the integrity of the tax system. Resolving this tension necessitates an ethics-infused judgment process. Ethical failures over the past decade have weakened the tax profession and called into question the extent to which practitioners in fact operate in a manner consistent with the public interest. In this paper, we explore the fundamental causes of the ethical problems that have plagued the tax profession and provide a roadmap for reform of the tax profession. Using Cressey’s (1953) fraud triangle as a framework, we first examine the normative ideal for the tax profession. We then examine the recent tax shelter abuses perpetrated by the major public accounting firms and find results consistent with our expectations under the fraud triangle analysis. In essence, ethical breakdowns resulted from the loss of a public interest emphasis, which in turn led to the explicit pursuit of commercial gain at the expense of the public interest. That the frauds were perpetrated within the context of a profession founded on a public interest notion is particularly concerning. In response to the problems observed, we identify key cultural reforms needed within the accounting academy, the accounting profession, and the tax system in order to restore trust and the public interest character of the tax profession to center stage and so guard against further adverse outcomes.

Probing Yukawa unification with K and B mixing

We consider corrections to the unification of down-quark and charged-lepton Yukawa couplings in supersymmetric GUTs, which links the large ντ−νμ mixing angle to b → s transitions. These corrections generically occur in simple grand-unified models with small Higgs representations and affect s → d and b → d transitions via the mixing of the corresponding right-handed superpartners. On the basis of a specific SUSY-SO(10) model, we analyze the constraints from K− and Bd−d mixing on the additional R−R rotation angle θ. We find that K already sets a stringent bound on θ, θmax ~ (1°), indicating a very specific flavor structure of the correction operators. The impact of the large neutrino mixings on the unitarity triangle analysis is also briefly discussed, as well as their ability to account for the sizeable CP-violating phase observed recently in Bs → J/ψ decays.

Update of the Unitarity Triangle Analysis

We present the update of the Unitarity Triangle (UT) analysis within the Standard Model (SM) and beyond. Within the SM, combining the direct measurements on sides and angles, the UT turns out to be overconstrained in a consistent way, showing that the CKM matrix is the dominant source of flavour mixing and CP-violation and that New Physics (NP) effects can appear at most as small corrections to the CKM picture. Generalizing the UT analysis to investigate NP effects, constraints on b → s transitions are also included and both CKM and NP parameters are fitted simultaneously. While no evidence of NP effects is found in K- K ¯ and B d - B ¯ d mixing, in the B s - B ¯ s mixing an hint of NP is found at the 2.9 σ level. The UT analysis beyond the SM also allows us to derive bounds on the coefficients of the most general Δ F = 2 effective Hamiltonian, that can be translated into bounds on the NP scale.

Contrarotating Turbine Aerodesign for an Advanced Hypersonic Propulsion System

Contrarotating turbomachinery is part of a novel airbreathing system to power a vehicle from takeoff to hypersonic speeds. The turbine-based combined cycle precools the inlet air before compression, with the hydrogen fuel as the heat-rejection sink. To ensure a safe engine operation, a helium loop is introduced between the air and hydrogen cycles; the helium drives the turbines of the main turbocompressor. The high speed of sound and low compressibility of the helium results in subsonic blading with low divergence of the endwalls. This paper describes in detail the aerodesign procedure of contrarotating helium turbines, which allows a net reduction in turbine size while augmenting the turbine efficiency. The design methodology is reviewed starting from the preliminary velocity triangle analysis. Studies were conducted to determine the effect over efficiency, outlet swirl and periodicity of the blade height, degree of reaction, and work distribution. The three-dimensional optimizer demands efficient parameterization techniques to account for the lean/sweep/twist geometry. The present multidisciplinary design includes the calculation of the centrifugal stresses. Three different helium turbine architectures have been designed and optimized, with special care to ensure an adequate performance at offdesign operation, and particular attention was devoted to minimize the secondary flows.

Status of the unitarity triangle analysis in the standard model

We present the update of the Unitarity Triangle analysis in the Standard Model. Combining the direct measurements on sides and angles of the Unitarity Triangle, we determine the values of the CKM parameters ρ̄ and η̄. This set of information provides a very poweful test of the Standard Model in the fermion sector. Thanks to the fact that the fit is overconstraint, we can predict hadronic QCD parameters without relying on any theoretical calculation of hadronic elements.

Probing the TeV scale (and above) with flavor physics

Generalizing the unitarity triangle analysis to include new physics effects, we derive upper bounds on the coefficients of the most general δF = 2 effective Hamiltonian. These upper bounds can be translated into lower bounds on the scale of new physics that contributes to these low-energy effective interactions. We conclude that the scale of new physics in models that generate new δF = 2 operators, such as next-to-minimal flavor violation, has to be much higher than the scale of minimal flavor violation, and it most probably lies beyond the reach of direct searches at the LHC. Updated results are available on http://www.utfit.org.

Model-independent constraints on ΔF= 2 operators and the scale of new physics

We update the constraints on new-physics contributions to Delta F=2 processes from the generalized unitarity triangle analysis, including the most recent experimental developments. Based on these constraints, we derive upper bounds on the coefficients of the most general Delta F=2 effective Hamiltonian. These upper bounds can be translated into lower bounds on the scale of new physics that contributes to these low-energy effective interactions. We point out that, due to the enhancement in the renormalization group evolution and in the matrix elements, the coefficients of non-standard operators are much more constrained than the coefficient of the operator present in the Standard Model. Therefore, the scale of new physics in models that generate new Delta F=2 operators, such as next-to-minimal flavour violation, has to be much higher than the scale of minimal flavour violation, and it most probably lies beyond the reach of direct searches at the LHC.

Investigating the physics case of running a B-factory at theUpsilon(5S)resonance

We discuss the physics case of a high luminosity B-Factory running at the Y(5S) resonance. We show that the coherence of the B meson pairs is preserved at this resonance, and that Bs can be well distinguished from Bd and charged B mesons. These facts allow to cover the physics program of a traditional B-Factory and, at the same time, to perform complementary measurements which are not accessible at the Y(4S). In particular we show how, despite the experimental limitations in performing time-dependent measurements of Bs decays, the same experimental information can be extracted, in several cases, from the determination of time-integrated observables. In addition, a few examples of the potentiality in measuring rare Bs decays are given. Finally, we discuss how the study of Bs meson will improve the constraints on New Physics parameters in the Bs sector, in the context of the generalized Unitarity Triangle analysis.

“Vybuchovy trojuhelnik”: A software tool for evaluation of explosibility of coal mine atmosphere

Rescue operations during mine fires or methane explosions are highly dangerous for rescue workers. The knowledge of the composition of the coal mine atmosphere and the calculations of its explosibility may help to increase the safety of the rescuers. In the Czech Republic, a system called “Mine Gas Laboratory” (DPL) has been used for these purposes. The DPL allows measurement of the composition of the mine atmosphere and transmits the data necessary for evaluation to the surface. Up to now the explosibility evaluation of the coal mine atmosphere has depended either on the rescuers’ experience or on software code calculation. The code called “Vybuchovy trojuhelnik” (explosion triangle) is a graphical computing system intended for fast assessment of explosibility of fuel–air mixture. This article introduces the code and describes two simple methods of explosibility evaluation. The first method is “explosion triangle analysis”—a graphical method based on empirical graphs transformed into equations. The second method uses thermodynamic calculation based on chemical balance dynamics and Gibbs and Helmholtz energy. According to the requirements of the Czech Bureau of Mining (CBU) and Central Mine Rescue Service (HBZS), the code solves the problems of explosion triangle for both standard and non-standard coal mine atmosphere compositions. Unfortunately, the atmosphere composition must be introduced manually due to the unknown format of the data transmitted from the old DPL model. On 1 September 2005, a project started to develop a new system for on-line monitoring and atmosphere explosibility evaluation. The system should be able to measure CO 2, O 2, CH 4, H 2 and CO concentrations as well as the wind speed, temperature and humidity. The “Vybuchovy trojuhelnik” code will be used as a basis for explosibility evaluation, and an on-line connection with the new model of DPL will be established.

Shaft Power Matching and Performance Prediction for Contra-Rotating Axial Flow Fans

The purpose of shaft power matching of contra-rotating axial flow fans (CRAFF) is to ensure the best utilization of the motors at their rated power while not to overload them at the operation.Usually it requires a lot of time and effort due to lack of theoretical guidance and, thus, becomes a major problem for the application of CRAFF. Through analyzing velocity triangle, the authors have found a nondimensional parameter k, defined as the tangential ratio of two relative outflow angles for two impellers, to be critical for successful shaft power matching and aerodynamic design. The authors then performed a numerical simulation of the flow field for a design of CRAFF, of which the performance prediction was validated very well by test data. Based on the analysis of the flow filed data, the result obtained from the velocity triangle analysis is further improved and some values for k and deviation angle δ are recommended. In order to determine the approximate optimum of blade pitch angles of two impellers, a guideline for shaft power matching is then presented. Finally, a comparison of the blade pitch angles obtained from the guideline with that obtained from the optimum using numerical simulation are carried out for six designs of CRAFF. The errors are only within 2 degrees.

Lattice QCD confronts the Unitarity Triangle Fit

Before the starting of the B factories, the Unitarity Triangle (UT) analysis relied on the results of lattice QCD simulations to relate the experimental determinations of semileptonic B decays, K 0 − K ¯ 0 and B d , s 0 − B ¯ d , s 0 mixing to the CKM parameters. In the last years, much more information has been obtained from the direct determination of the UT angles from non-leptonic B decays. In this talk, we compare the results of the “classical” UT analysis (UTlattice) with the analysis based on the angles determinations (UTangles). We show that the recent measurement of Δ m s , combined with Δ m d and e K , allows from this comparison a quite accurate extraction of the values of the lattice parameters, B ˆ K , f B s B ˆ B s 1 / 2 , ξ and f B . These values, obtained “experimentally” by assuming the validity of the Standard Model, can be compared with the theoretical predictions from lattice QCD. We also discuss the different determinations of V u b and show that current data do not favor the value measured in inclusive decays. Finally, we present updated predictions for the leptonic branching fraction B R ( B → τ ν τ ) , and compare them with the recent experimental determination. We take the opportunity of this write up to update the results of ref. [M. Bona et al. [UTfit Collaboration], arXiv:hep-ph/0606167 ] with the most recent results presented at the ICHEP'06 conference.

B-meson mixing and lifetimes

$B_d$ and $B_s$ meson systems play a fundamental role to test and improve our understanding of Standard Model flavor dynamics. The mixing parameters $\Delta m_{d,s}$ represent important constraints in the unitarity triangle analysis. Their theoretical estimates require non-perturbative calculations of B-meson decay constants and B-parameters; accurate results, recently obtained from the lattice, are reviewed. Other phenomenologically interesting quantities are the beauty hadron lifetime ratios and, the width differences and CP-violation parameters in $B_d$ and $B_s$ systems. We discuss their theoretical predictions which, in the last four years, have been improved thanks to accurate lattice calculations and next-to-leading order perturbative computations.

Developing a Methodology for Aligning Supply Chains from a Relationships Perspective

The research presented in this paper has focussed on exploring buyer—supplier relationships from a human perspective. The research has been successful in exploring issues affecting buyer—supplier relationships. A methodology for aligning supply chains by taking into account human issues has been proposed. The methodology consists of a relationship framework that is used for studying buyer—supplier relationships on a macro-level based on the levels of satisfaction that the entities have with each other. Since high levels of dissatisfaction lead to various change—inducing transactions or game-like behaviour between the entities, the framework identifies the status of the relationship, and can be used to gauge what is going to happen to it, once the transaction is over. The concepts of transactional analysis and the tools associated with it, namely drama triangle analysis and structural modelling, are useful in studying the dynamics of the transactions from the human perspective and also from a psychological perspective.

Architecture with GIDEON, a program for design in structural DNA nanotechnology

We present geometry based design strategies for DNA nanostructures. The strategies have been implemented with GIDEON—a graphical integrated development environment for oligonucleotides. GIDEON has a highly flexible graphical user interface that facilitates the development of simple yet precise models, and the evaluation of strains therein. Models are built on a simple model of undistorted B-DNA double-helical domains. Simple point and click manipulations of the model allow the minimization of strain in the phosphate-backbone linkages between these domains and the identification of any steric clashes that might occur as a result. Detailed analysis of 3D triangles yields clear predictions of the strains associated with triangles of different sizes. We have carried out experiments that confirm that 3D triangles form well only when their geometrical strain is less than 4% deviation from the estimated relaxed structure. Thus geometry-based techniques alone, without detailed energetic considerations, can be used to explain certain general trends in DNA structure formation. We have used GIDEON to build detailed models of double crossover and triple crossover molecules, evaluating the non-planarity associated with base tilt and junction misalignments. Computer modeling using a graphical user interface overcomes the limited precision of physical models for larger systems, and the limited interaction rate associated with earlier, command-line driven software.

The UTfit collaboration report on the status of the unitarity triangle beyond the Standard Model I. Model-independent analysis and minimal flavour violation

Starting from a (new physics independent) tree level determination of and , we perform the Unitarity Triangle analysis in general extensions of the Standard Model with arbitrary new physics contributions to loop-mediated processes. Using a simple parameterization, we determine the allowed ranges of non-standard contributions to |ΔF| = 2 processes. Remarkably, the recent measurements from B factories allow us to determine with good precision the shape of the Unitarity Triangle even in the presence of new physics, and to derive stringent constraints on non-standard contributions to |ΔF| = 2 processes. Since the present experimental constraints favour models with Minimal Flavour Violation, we present the determination of the Universal Unitarity Triangle that can be defined in this class of extensions of the Standard Model. Finally, we perform a combined fit of the Unitarity Triangle and of new physics contributions in Minimal Flavour Violation, reaching a sensitivity to a new physics scale of about 5 TeV. We also extrapolate all these analyses into a ``year 2010'' scenario for experimental and theoretical inputs in the flavour sector. All the results presented in this paper are also available at the URL http://www.utfit.org, where they are continuously updated.

One-loop matching ofΔS=2four-quark operators with improved staggered fermions

We compute O({alpha}{sub s}) lattice-to-continuum perturbative matching coefficients for the {delta}S=2 flavor changing four-quark operators for the Asqtad improved staggered action. In conjunction with lattice simulations with three flavors of light, dynamical quarks, our results yield an unquenched determination of B{sub K}, the parameter that determines the amount of indirect CP violation in the neutral kaon system. Its value is an important input for the unitarity triangle analysis of weak decays.