Real Gauge Research Articles

Electroweak Sudakov logarithms and real gauge-boson radiation in the TeV region

Electroweak radiative corrections give rise to large negative, double-logarithmically enhanced corrections in the TeV region. These are partly compensated by real radiation and, moreover, affected by selecting isospin-noninvariant external states. We investigate the impact of real gauge boson radiation more quantitatively by considering different restricted final state configurations. We consider successively a massive abelian gauge theory, a spontaneously broken SU(2) theory and the electroweak Standard Model. We find that details of the choice of the phase space cuts, in particular whether a fraction of collinear and soft radiation is included, have a strong impact on the relative amount of real and virtual corrections.

TeV scale dark matter and electroweak radiative corrections

Recent anomalies in cosmic rays data, namely, from the PAMELA Collaboration, can be interpreted in terms of TeV scale decaying/annihilating dark matter. We analyze the impact of radiative corrections coming from the electroweak sector of the standard model on the spectrum of the final products at the interaction point. As an example, we consider virtual one loop corrections and real gauge bosons emission in the case of a very heavy vector boson annihilating into fermions. We find electroweak corrections that are relevant, but not as big as sometimes found in the literature; we relate this mismatch to the issue of gauge invariance. At scales much higher than the symmetry breaking scale, one loop electroweak effects are so big that eventually higher orders/resummations have to be considered: we advocate for the inclusion of these effects in parton shower Monte Carlo models aiming at the description of TeV scale physics.

CP violation in the general two-Higgs-doublet model: a geometric view

We discuss the CP properties of the potential in the general two-Higgs-doublet model (THDM). This is done in a concise way using real gauge invariant functions built from the scalar products of the doublet fields. The space of these invariant functions, parametrising the gauge orbits of the Higgs fields, is isomorphic to the forward light cone and its interior. CP transformations are shown to correspond to reflections in the space of the gauge invariant functions. We consider CP transformations where no mixing of the Higgs doublets is taken into account as well as the general case where the Higgs basis is not fixed. We present basis independent conditions for explicit CP violation which may be checked easily for any THDM potential. Conditions for spontaneous CP violation, that is CP violation through the vacuum expectation values of the Higgs fields, are also derived in a basis independent way.

Analytic solutions for marginal deformations in open superstring field theory

We construct analytic solutions for marginal deformations satisfying the reality condition in open superstring field theory formulated by Berkovits when operator products made of the marginal operator and the associated superconformal primary field are regular. Our strategy is based on the recent observation by Erler that the problem of finding solutions for marginal deformations in open superstring field theory can be reduced to a problem in the bosonic theory of finding a finite gauge parameter for a certain pure-gauge configuration labeled by the parameter of the marginal deformation. We find a gauge transformation generated by a real gauge parameter which infinitesimally changes the deformation parameter and construct a finite gauge parameter by its path-ordered exponential. The resulting solution satisfies the reality condition by construction.

Real analytic solutions for marginal deformations in open superstring field theory

We construct analytic solutions for marginal deformations satisfying the reality condition in open superstring field theory formulated by Berkovits when operator products made of the marginal operator and the associated superconformal primary field are regular. Our strategy is based on the recent observation by Erler that the problem of finding solutions for marginal deformations in open superstring field theory can be reduced to a problem in the bosonic theory of finding a finite gauge parameter for a certain pure-gauge configuration labeled by the parameter of the marginal deformation. We find a gauge transformation generated by a real gauge parameter which infinitesimally changes the deformation parameter and construct a finite gauge parameter by its path-ordered exponential. The resulting solution satisfies the reality condition by construction.

Simulation of Strain Gauge Thermal Effects During Residual Stress Hole Drilling Measurements

The hole drilling residual stress measuring method is based on drilling a small hole in a material sample and measuring the strain relieved in the hole vicinity by a special strain gauge rosette. The temperature and thermal strain induced by the drilling process can cause significant errors in the relieved strain measurement. The paper deals with computer simulation of the thermomechanical process in the sample during drilling. The first part is devoted to the evaluation of heat flux from the drilling tool to the drilled material using the sample surface temperature measured by thermography. The second part deals with determination of real strain and strain gauge thermal output (apparent strain) at the strain gauge location during and after drilling. The paper describes the computer modelling technique for solving an indirect thermal problem of drilling heat flux determination and a direct thermomechanical problem for a set of the process alternatives. Comparisons of simulated and experimentally determined temperatures and strains are presented.

Contributions of in‐plane fabric tensile properties in woven fabric bagging behaviour using a new developed test method

To investigate the relation of in‐plane fabric tensile properties with woven fabrics bagging behavior, a new test method was developed and a real time data acquisition and strain gauge technique were used. The bagging procedure was carried out while the woven fabric tensile deformations along warp and weft directions were measured. The fabric bagging behavior was characterized by bagging resistance, bagging fatigue, residual bagging height and residual bagging hysteresis. The experimental results show that the bagging load, work, hysteresis, residual hysteresis and fatigue are highly linearly correlated with corresponding parameters in warp and weft directions. An empirical relationship obtained between residual bagging height and bagging fatigue and resistance (R2=0.83) suggests that the proposed new test method is able to evaluate bagging behavior of fabrics.

Lepton mixing angle 13= 0 with a horizontal symmetryD4

We discuss a model for the lepton sector based on the seesaw mechanism and on a $D_4$ family symmetry. The model predicts the mixing angle $\theta_{13}$ to vanish. The solar mixing angle $\theta_{12}$ is free--it will in general be large if one does not invoke finetuning. The model has an enlarged scalar sector with three Higgs doublets, together with two real scalar gauge singlets $\chi_i$ ($ i = 1, 2$) which have vacuum expectation values < \chi_i >_0$ at the seesaw scale. The atmospheric mixing angle $\theta_{23}$ is given by $\tan \theta_{23} = <\chi_2>_0$ /<\chi_1>_0$, and it is maximal if the Lagrangian is $D_4$-invariant; but $D_4$ may be broken softly, by a term of dimension two in the scalar potential, and then < \chi_2_0$ becomes different from < \chi_1_0$. Thus, the strength of the soft $D_4$ breaking controls the deviation of $\theta_{23}$ from $\pi / 4$. The model predicts a normal neutrino mass spectrum ($m_3 > m_2 > m_1$) and allows successful leptogenesis if $m_1 \sim 4 \times 10^{-3} \mathrm{eV}$; these properties of the model are independent of the presence and strength of the soft $D_4$ breaking.

Tsunami waveform inversion by adjoint methods

An adjoint method for tsunami waveform inversion is proposed, as an alternative to the technique based on Green's functions of the linear long wave model. The method has the advantage of being able to use the nonlinear shallow water equations, or other appropriate equation sets, and to optimize an initial state given as a linear or nonlinear function of any set of free parameters. This last facility is used to perform explicit optimization of the focal fault parameters, characterizing the initial sea surface displacement of tsunamigenic earthquakes. The proposed methodology is validated with experiments using synthetic data, showing the possibility of recovering all relevant details of a tsunami source from tide gauge observations, providing that the adjoint method is constrained in an appropriate manner. It is found, as in other methods, that the inversion skill of tsunami sources increases with the azimuthal and temporal coverage of assimilated tide gauge stations; furthermore, it is shown that the eigenvalue analysis of the Hessian matrix of the cost function provides a consistent and useful methodology to choose the subset of independent parameters that can be inverted with a given dataset of observations and to evaluate the error of the inversion process. The method is also applied to real tide gauge series, from the tsunami of the February 28, 1969, Gorringe Bank earthquake, suggesting some reasonable changes to the assumed focal parameters of that event. It is suggested that the method proposed may be able to deal with transient tsunami sources such as those generated by submarine landslides.

Nonlinear self-duality in even dimensions

We show that the Born–Infeld theory with n complex abelian gauge fields written in an auxiliary field formulation has a U(n,n) duality group. We conjecture the form of the Lagrangian obtained by eliminating the auxiliary fields and then introduce a new reality structure leading to a Born–Infeld theory with n real gauge fields and an Sp(2n,R) duality symmetry. The real and complex constructions are extended to arbitrary even dimensions. The maximal noncompact duality group is U(n,n) for complex fields. For real fields the duality group is Sp(2n,R) if half of the dimension of space-time is even and O(n,n) if it is odd. We also discuss duality under the maximal compact subgroup, which is the self-duality group of the theory obtained by fixing the expectation value of a scalar field. Supersymmetric versions of self-dual theories in four dimensions are also discussed.

Measuring the Impact of Sponsorship

Introduction Sponsors are increasingly concerned about what results they are getting for their sponsorship dollars. In the 1980s when sponsorship was the hot marketing tool, corporate involvement boomed. Properties came-a-callin' and companies were willing to answer that call. Accountability seemed less an issue than the chance for corporate chieftains to exercise their egos. The chance to sidle up to big name stars or to have one's company associated with a major cause or event, irrespective of the value of that alignment to the company, was often overpowering. As the 1990s draw to a close, the scenario has changed. Big money still chases sponsorships, but with a twist. The value of sponsorships is being called into question much more often than in the past. Every aspect of the marketing mix, from advertising to direct marketing to sales promotion to couponing is under intense scrutiny and sponsorship is no exception. In fact, sponsorships are under a particularly strong microscope. And no wonder. The cost of sponsorship can be staggering. Olympic sponsorship 20 years ago (prior to the Los Angeles games) could be had for $5 to 10 million. Today, rights fees fetch $40 million. World Cup sponsorship in 1996 was upwards of $35 million. Several years ago, Coca-Cola paid a whopping $250 million to be the official drink of the NFL. Obviously, many sponsorships are not played out on a nationwide or worldwide stage. Rights fees can be much more modest than the multi-million dollar asking prices described above. Nevertheless, marketing managers still have to justify their allocation of marketing dollars to sponsorship. The cry now heard in more and more corporations is: Just what are we getting out of these sponsorships, anyway? Marketing directors and even CEOs are being challenged to justify their forays into event marketing and to quantify the value of their sponsorships. So, how does one go about determining what a sponsorship is doing for a company? How does one determine whether or not a sponsorship is returning anything to the bottom line? It seems to us that one difficulty that event marketers have in trying to figure out just what their sponsorships are doing is that they are either unable or unwilling to find out the answer! In some instances, the feeling is that there is no real accurate gauge for determining success, especially if the sponsorship is pursued as a means of improving relationships or boosting employee morale. These seemingly soft criteria are considered by some in the field to be impossible to measure. Yet another reason for avoiding measures of effectiveness is fear! Some event marketers try to avoid solid measurement because they worry that the answer will not be to their liking (a phobia we in the advertising business also suffer from on occasion). They know in their guts that the sponsorship was beneficial, but avoid trying to quantify these feelings for fear of being proven wrong. Ironically, the slower we pursue measuring the value of sponsorship, the quicker we may hasten sponsorship's demise. If we do not provide fair and objective estimates of the effects of sponsorship, there may be less money available for sponsorship activities as marketing dollars are allocated elsewhere--perhaps to those areas of marketing that can demonstrate effectiveness. Evaluating a sponsorship is not usually straightforward. * There may be imperfect or even conflicting evidence as to what happened. * There may be a problem deciding what is the relationship between cause and effect. * Because other elements of the marketing mix may be active at the time of the sponsorship, isolating the effects of the sponsorship may be problematic. * Because one sponsorship may work differently from another there may be no all-purpose solution for measuring impact. Despite these problems, we should not give up. …

Manifestly gauge covariant treatment of lattice chiral fermions. II

We propose a formulation of chiral fermions on a lattice, on the basis of a lattice extension of the covariant regularization scheme in continuum field theory. The species doublers do not emerge. The real part of the effective action is just one-half of that of Dirac-Wilson fermion and is always gauge invariant even with a finite lattice spacing. The gauge invariance of the imaginary part, on the other hand, sets a severe constraint that is a lattice analog of the gauge anomaly-free condition. For real gauge representations, the imaginary part identically vanishes and the gauge invariance becomes exact.

Coherent State Transforms for Spaces of Connections

The Segal–Bargmann transform plays an important role in quantum theories of linear fields. Recently, Hall obtained a non-linear analog of this transform for quantum mechanics on Lie groups. Given a compact, connected Lie groupGwith its normalized Haar measureμH, the Hall transform is an isometric isomorphism fromL2(G, μH) toH(GC)∩L2(GC, ν), whereGCthe complexification ofG,H(GC) the space of holomorphic functions onGC, andνan appropriate heat-kernel measure onGC. We extend the Hall transform to the infinite dimensional context of non-Abelian gauge theories by replacing the Lie groupGby (a certain extension of ) the spaceA/Gof connections modulo gauge transformations. The resulting “coherent state transform” provides a holomorphic representation of the holonomyC* algebra of real gauge fields. This representation is expected to play a key role in a non-perturbative, canonical approach to quantum gravity in 4 dimensions.

Meissner effect in scalar QED with magnetic moment interactions.

We examine a model which describes the interactions of charged magnetic scalar particles with real gauge fields in 2+1 dimensions. At zero temperature and finite density, in the nonrelativistic mean field limit, the scalar fields have fractional statistics, and the theory contains the Meissner effect. In this limit, our model is effectively a reparametrization of the model that contains a Chern-Simons term for a statistical gauge field and couples the scalar field to the statistical gauge field and a real, dynamical gauge field. At high temperature, our model has a phase transition to the state where magnetic fields penetrate the system.

Phenomenological study of the process e+e---> micro+ micro- nu l nu -barl at high energy e+e- colliders and measurement of the ZWW and gamma WW couplings.

We perform a detailed study of the process $e^+e^-\to \mu^+\mu^-\nu_l\bar\nu_l$ including all contributions. The contributions other than from real gauge boson production leads to a rich phenomenology. We explore the use of the process as a means of precision measurement of the $ZWW$ and $\gamma WW$ vertices. We concentrate on LEP II energies, $\sqrt{s}=200$ GeV, and energies appropriate to the proposed Next Linear Collider (NLC) high energy $e^+e^-$ collider with center of mass energies $\sqrt{s}=500$ and 1~TeV. At 200 GeV, the process offers, at best, a consistency check of other processes being considered at LEP200. At 500~GeV, the parameters $\kappa_\gamma$, $\lambda_\gamma$, $\kappa_Z$, and $\lambda_Z$ can be measured to about $\pm 0.1$ or better at 95\% C.L. while at 1 TeV, they can be measured to about $\pm 0.01$. At the high luminosities anticipated at high energy linear colliders precision measurements are likely to be limited by systematic rather than statistical errors.

Topological gauge field mass generation by toroidal spacetime

The author considers an Abelian gauge field theory on Euclidean partially compactified spacetime TN*Rn for arbitrary N and n. The one-loop effective potential generated by quantum fluctuations of a massive scalar field, minimally coupled to a constant background Abelian gauge potential is calculated for arbitrary compactification lengths L1,. . .,LN of the multi-dimensional torus. In particular the topologically generated mass of the gauge field is obtained and its complicated dependence on the parameters involved (compactification lengths, mass M of the scalar field) is given explicitly. It is found that the topologically generated mass is positive for arbitrary N and n and that it does not depend on a renormalization parameter. For n>2 the limit M to 0 is smooth, but for n=0,1,2 zero modes play a crucial role and the generation of real or imaginary gauge field masses is possible.

METRIC FROM NONMETRIC ACTION OF GRAVITY

The action of general relativity proposed by Capovilla, Jacobson and Dell is written in terms of SO(3) gauge fields and gives Ashtekar's constraints for Einstein gravity. However, it does not depend on the spacetime metric nor its signature explicitly. We discuss how the spacetime metric is introduced from algebraic relations of the constraints and the form of the Hamiltonian by focusing our attention on the signature factor. The system describes both Euclidean and Lorentzian metrics depending on reality assignments of the gauge connections. That is, Euclidean metrics arise from the real gauge fields. On the other hand, self-duality of the gauge fields, which is well known in the Ashtekar formalism, is derived in this theory from the consistency condition of the Lorentzian metric. We also show that the metric so determined is equivalent to that given by Urbantke, which is usually accepted as a definition of the metric for this system.

Complex static solutions and wave solutions to (2+1)-dimensional topologically massive gauge theories

Complex static solutions with zero action and zero energy-momentum tensor are constructed for the (2+1)-dimensional topologically massive SU(2) gauge theory by generalizing the vortex-like solutions. These solutions can be treated as real gauge potentials for the noncompact gauge group SL(2, C ). Wave solutions are also exhibited.

All-Order No-Renormalization of the Mass and Interaction Lagrangians for Anti-de Sitter Supersymmetry

We consider the interacting model of chiral and real gauge superfields in Anti-de Sitter space. The superconformal invariance of the massless model allows us to implement an expansion in the curvature effects in terms of the interaction vertices of the quantum model. In a previous application of the superfield formalism, the renormalization of the linear superfield term in the superpotential was derived. In the present work, it is argued that simple power counting arguments suffice to prove the no-renormalization of the mass and chiral self-interaction actions to all orders in perturbation theory.

Very high strain sensitivity in thick-film resistors: real and false super gauge factors

An investigation has been carried out on the correlations between composition/morphology of RuO 2-based thick-film resistors and their strain sensitivity. Very high gauge factors ( GFs), as well as satisfactory performance in terms of TCR (temperature coefficient of resistance), excess noise and reliability, are obtained with an appropriate choice of glassy matrix, RuO 2 grain size and concentrations. Resistive systems modified with metal and metal oxide additions are also analysed. In some cases notable changes of electrical properties are observed, related to defective structures. Methods for a simple and accurate diagnosis of reliable or fictitious performance of thick-film strain gauges are identified.