The Universal One-Loop Effective Action
Drozd, Aleksandra; Quevillon, Jérémie; You, Tevong
2016-01-01
We present the universal one-loop effective action for all operators of dimension up to six obtained by integrating out massive, non-degenerate multiplets. Our general expression may be applied to loops of heavy fermions or bosons, and has been checked against partial results available in the literature. The broad applicability of this approach simplifies one-loop matching from an ultraviolet model to a lower-energy effective field theory (EFT), a procedure which is now reduced to the evaluation of a combination of matrices in our universal expression, without any loop integrals to evaluate. We illustrate the relationship of our results to the Standard Model (SM) EFT, using as an example the supersymmetric stop and sbottom squark Lagrangian and extracting from our universal expression the Wilson coefficients of dimension-six operators composed of SM fields.
The universal one-loop effective action
International Nuclear Information System (INIS)
Drozd, Aleksandra; Ellis, John; Quevillon, Jérémie; You, Tevong
2016-01-01
We present the universal one-loop effective action for all operators of dimension up to six obtained by integrating out massive, non-degenerate multiplets. Our general expression may be applied to loops of heavy fermions or bosons, and has been checked against partial results available in the literature. The broad applicability of this approach simplifies one-loop matching from an ultraviolet model to a lower-energy effective field theory (EFT), a procedure which is now reduced to the evaluation of a combination of matrices in our universal expression, without any loop integrals to evaluate. We illustrate the relationship of our results to the Standard Model (SM) EFT, using as an example the supersymmetric stop and sbottom squark Lagrangian and extracting from our universal expression the Wilson coefficients of dimension-six operators composed of SM fields.
One-Loop Effective Action in Orbifold Compactifications
Von Gersdorff, Gero
2008-01-01
We employ the covariant background formalism to derive generic expressions for the one-loop effective action in field theoretic orbifold compactifications. The contribution of each orbifold sector is given by the effective action of its fixed torus with a shifted mass matrix. We thus study in detail the computation of the heat kernel on tori. Our formalism manifestly separates UV sensitive (local) from UV-insensitive (nonlocal) renormalization. To exemplify our methods, we study the effective potential of 6d gauge theory as well as kinetic terms for gravitational moduli in 11d supergravity.
One-loop effective actions and higher spins. Part II
Bonora, L.; Cvitan, M.; Prester, P. Dominis; Giaccari, S.; Štemberga, T.
2018-01-01
In this paper we continue and improve the analysis of the effective actions obtained by integrating out a scalar and a fermion field coupled to external symmetric sources, started in the previous paper. The first subject we study is the geometrization of the results obtained there, that is we express them in terms of covariant Jacobi tensors. The second subject concerns the treatment of tadpoles and seagull terms in order to implement off-shell covariance in the initial model. The last and by far largest part of the paper is a repository of results concerning all two point correlators (including mixed ones) of symmetric currents of any spin up to 5 and in any dimensions between 3 and 6. In the massless case we also provide formulas for any spin in any dimension.
A gauge/gravity relation in the one-loop effective action
International Nuclear Information System (INIS)
Basar, Goekce; Dunne, Gerald V
2010-01-01
We identify an unusual new gauge/gravity relation: the one-loop effective action for a massive spinor in 2n-dimensional AdS space is expressed in terms of precisely the same function (a certain multiple gamma function) as the one-loop effective action for a massive charged scalar in 4n dimensions in a maximally symmetric background electromagnetic field (one for which the eigenvalues of F μν are maximally degenerate, corresponding in four dimensions to a self-dual field, equivalently to a field of definite helicity), subject to the identification F 2 ↔Λ, where Λ is the gravitational curvature. Since these effective actions generate the low energy limit of all one-loop multi-leg graviton or gauge amplitudes, this implies a nontrivial gauge/gravity relation at the non-perturbative level and at the amplitude level. (fast track communication)
Mixed heavy–light matching in the Universal One-Loop Effective Action
International Nuclear Information System (INIS)
Ellis, Sebastian A.R.; Quevillon, Jérémie; You, Tevong; Zhang, Zhengkang
2016-01-01
Recently, a general result for evaluating the path integral at one loop was obtained in the form of the Universal One-Loop Effective Action. It may be used to derive effective field theory operators of dimensions up to six, by evaluating the traces of matrices in this expression, with the mass dependence encapsulated in the universal coefficients. Here we show that it can account for loops of mixed heavy–light particles in the matching procedure. Our prescription for computing these mixed contributions to the Wilson coefficients is conceptually simple. Moreover it has the advantage of maintaining the universal structure of the effective action, which we illustrate using the example of integrating out a heavy electroweak triplet scalar coupling to a light Higgs doublet. Finally we also identify new structures that were previously neglected in the universal results.
Partially massless higher-spin theory II: one-loop effective actions
Energy Technology Data Exchange (ETDEWEB)
Brust, Christopher [Perimeter Institute for Theoretical Physics,31 Caroline St. N, Waterloo, Ontario, N2L 2Y5 (Canada); Hinterbichler, Kurt [CERCA, Department of Physics, Case Western Reserve University,10900 Euclid Ave, Cleveland, OH, 44106 (United States)
2017-01-30
We continue our study of a generalization of the D-dimensional linearized Vasiliev higher-spin equations to include a tower of partially massless (PM) fields. We compute one-loop effective actions by evaluating zeta functions for both the “minimal” and “non-minimal” parity-even versions of the theory. Specifically, we compute the log-divergent part of the effective action in odd-dimensional Euclidean AdS spaces for D=7 through 19 (dual to the a-type conformal anomaly of the dual boundary theory), and the finite part of the effective action in even-dimensional Euclidean AdS spaces for D=4 through 8 (dual to the free energy on a sphere of the dual boundary theory). We pay special attention to the case D=4, where module mixings occur in the dual field theory and subtlety arises in the one-loop computation. The results provide evidence that the theory is UV complete and one-loop exact, and we conjecture and provide evidence for a map between the inverse Newton’s constant of the partially massless higher-spin theory and the number of colors in the dual CFT.
Partially massless higher-spin theory II: one-loop effective actions
International Nuclear Information System (INIS)
Brust, Christopher; Hinterbichler, Kurt
2017-01-01
We continue our study of a generalization of the D-dimensional linearized Vasiliev higher-spin equations to include a tower of partially massless (PM) fields. We compute one-loop effective actions by evaluating zeta functions for both the “minimal” and “non-minimal” parity-even versions of the theory. Specifically, we compute the log-divergent part of the effective action in odd-dimensional Euclidean AdS spaces for D=7 through 19 (dual to the a-type conformal anomaly of the dual boundary theory), and the finite part of the effective action in even-dimensional Euclidean AdS spaces for D=4 through 8 (dual to the free energy on a sphere of the dual boundary theory). We pay special attention to the case D=4, where module mixings occur in the dual field theory and subtlety arises in the one-loop computation. The results provide evidence that the theory is UV complete and one-loop exact, and we conjecture and provide evidence for a map between the inverse Newton’s constant of the partially massless higher-spin theory and the number of colors in the dual CFT.
A covariant technique for the calculation of the one-loop effective action
International Nuclear Information System (INIS)
Avramidi, I.G.
1991-01-01
We develop a manifestly covariant technique for a heat kernel calculation in the presence of arbitrary background fields in a curved space. The four lowest-order coefficients of the Schwinger-De Witt asymptotic expansion are explicitly computed. We also calculate the heat kernel asymptotic expansion up to terms of third order in rapidly varying background fields (curvatures). This approximate series is summed and covariant nonlocal expressions for the heat kernel, ξ-function and one-loop effective action are obtained. Other related problems are discussed. (orig.)
One-loop light-cone QCD, effective action for reggeized gluons and QCD RFT calculus
Energy Technology Data Exchange (ETDEWEB)
Bondarenko, S.; Pozdnyakov, S.; Prygarin, A. [Ariel University, Physics Department, Ariel (Israel); Lipatov, L. [St. Petersburg State University, St. Petersburg (Russian Federation); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation)
2017-09-15
The effective action for reggeized gluons is based on the gluodynamic Yang-Mills Lagrangian with external current for longitudinal gluons added, see Lipatov (Nucl Phys B 452:369, 1995; Phys Rep 286:131, 1997; Subnucl Ser 49:131, 2013; Int J Mod Phys Conf Ser 39:1560082, 2015; Int J Mod Phys A 31(28/29):1645011, 2016; EPJ Web Conf 125:01010, 2016). On the base of classical solutions, obtained in Bondarenko et al. (Eur Phys J C 77(8):527, 2017), the one-loop corrections to this effective action in light-cone gauge are calculated. The RFT calculus for reggeized gluons similarly to the RFT introduced in Gribov (Sov Phys JETP 26:414, 1968) is proposed and discussed. The correctness of the results is verified by calculation of the propagators of A{sub +} and A{sub -} reggeized gluons fields and application of the obtained results is discussed as well. (orig.)
International Nuclear Information System (INIS)
Jalilian-Marian, Jamal; Jeon, Sangyong; Venugopalan, Raju; Wirstam, Jens
2000-01-01
The one loop effective action in quantum field theory can be expressed as a quantum mechanical path integral over world lines, with internal symmetries represented by Grassmanian variables. In this paper, we develop a real time, many body, world line formalism for the one loop effective action. In particular, we study hot QCD and obtain the classical transport equations which, as Litim and Manuel have shown, reduce in the appropriate limit to the non-Abelian Boltzmann-Langevin equation first obtained by Boedeker. In the Vlasov limit, the classical kinetic equations are those that correspond to the hard thermal loop effective action. We also discuss the imaginary time world line formalism for a hot φ 4 theory, and elucidate its relation to classical transport theory. (c) 2000 The American Physical Society
An addendum to the Heisenberg-Euler effective action beyond one loop
Energy Technology Data Exchange (ETDEWEB)
Gies, Holger; Karbstein, Felix [Helmholtz-Institut Jena,Fröbelstieg 3, 07743 Jena (Germany); Theoretisch-Physikalisches Institut, Abbe Center of Photonics,Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena (Germany)
2017-03-21
We study the effective interactions of external electromagnetic fields induced by fluctuations of virtual particles in the vacuum of quantum electrodynamics. Our main focus is on these interactions at two-loop order. We discuss in detail the emergence of the renowned Heisenberg-Euler effective action from the underlying microscopic theory of quantum electrodynamics, emphasizing its distinction from a standard one-particle irreducible effective action. In our explicit calculations we limit ourselves to constant and slowly varying external fields, allowing us to adopt a locally constant field approximation. One of our main findings is that at two-loop order there is a finite one-particle reducible contribution to the Heisenberg-Euler effective action in constant fields, which was previously assumed to vanish. In addition to their conceptual significance, our results are relevant for high-precision probes of quantum vacuum nonlinearity in strong electromagnetic fields.
International Nuclear Information System (INIS)
Okawa, Yuji
1999-01-01
The one-loop effective action for general trajectories of D-particles in Matrix theory is calculated in the expansion with respect to the number of derivatives up to six, which gives the equation of motion consistently. The result shows that the terms with six derivatives vanish for straight-line trajectories, however, they do not vanish in general. This provides a concrete example that non-renormalization of twelve-fermion terms does not necessarily imply that of six-derivative terms
High-temperature expansion of the one-loop effective action induced by scalar and Dirac particles
Energy Technology Data Exchange (ETDEWEB)
Kalinichenko, Igor; Kazinski, Peter [Tomsk State University, Physics Faculty, Tomsk (Russian Federation)
2017-12-15
The complete nonperturbative expressions for the high-temperature expansion of the one-loop effective action induced by the charged scalar and the charged Dirac particles both at zero and finite temperatures are derived with account of possible nontrivial boundary conditions. The background electromagnetic field is assumed to be stationary and such that the corresponding Klein-Gordon operator or the Dirac Hamiltonian is self-adjoint. The contributions of particles and antiparticles are obtained separately. The explicit expressions for the C-symmetric and the non-C-symmetric vacuum energies of the Dirac fermions are derived. The leading corrections to the high-temperature expansion due to the nontrivial boundary conditions are explicitly found. The corrections to the logarithmic divergence of the effective action that come from the boundary conditions are derived. The high-temperature expansion of the naive one-loop effective action induced by charged fermions turns out to be divergent in the limit of a zero fermion mass. (orig.)
One-loop effective action for non-local modified Gauss-Bonnet gravity in de Sitter space
Energy Technology Data Exchange (ETDEWEB)
Cognola, Guido; Zerbini, Sergio [Universita di Trento (Italy); Istituto Nazionale di Fisica Nucleare Gruppo Collegato di Trento, Dipartimento di Fisica, Trento (Italy); Elizalde, Emilio [Consejo Superior de Investigaciones Cientificas (ICE/CSIC) and Institut d' Estudis Espacials de Catalunya (IEEC), Facultat Ciencies, Bellaterra (Barcelona) (Spain); Nojiri, Shin' ichi [Nagoya University, Department of Physics, Nagoya (Japan); Odintsov, Sergei D. [Consejo Superior de Investigaciones Cientificas (ICE/CSIC) and Institut d' Estudis Espacials de Catalunya (IEEC), Facultat Ciencies, Bellaterra (Barcelona) (Spain); ICREA, Barcelona (Spain); TSPU, Center of Theor. Phys., Tomsk (Russian Federation)
2009-12-15
We discuss the classical and quantum properties of non-local modified Gauss-Bonnet gravity in de Sitter space, using its equivalent representation via string-inspired local scalar-Gauss-Bonnet gravity with a scalar potential. A classical, multiple de Sitter universe solution is found where one of the de Sitter phases corresponds to the primordial inflationary epoch, while the other de Sitter space solution - the one with the smallest Hubble rate - describes the late-time acceleration of our universe. A Chameleon scenario for the theory under investigation is developed, and it is successfully used to show that the theory complies with gravitational tests. An explicit expression for the one-loop effective action for this non-local modified Gauss-Bonnet gravity in the de Sitter space is obtained. It is argued that this effective action might be an important step towards the solution of the cosmological constant problem. (orig.)
One-loop effective potential on hyperbolic manifolds
International Nuclear Information System (INIS)
Cognola, G.; Kirsten, K.; Zerbini, S.
1993-01-01
The one-loop effective potential for a scalar field defined on an ultrastatic space-time whose spatial part is a compact hyperbolic manifold is studied using ζ-function regularization for the one-loop effective action. Other possible regularizations are discussed in detail. The renormalization group equations are derived, and their connection with the conformal anomaly is pointed out. The symmetry breaking and the topological mass generation are also discussed
One-loop effective lagrangians after matching
Energy Technology Data Exchange (ETDEWEB)
Aguila, F. del; Santiago, J. [Universidad de Granada, Departamento de Fisica Teorica y del Cosmos and CAFPE, Granada (Spain); Kunszt, Z. [ETH Zuerich, Institute for Theoretical Physics, Zuerich (Switzerland)
2016-05-15
We discuss the limitations of the covariant derivative expansion prescription advocated to compute the one-loop Standard Model (SM) effective lagrangian when the heavy fields couple linearly to the SM. In particular, one-loop contributions resulting from the exchange of both heavy and light fields must be explicitly taken into account through matching because the proposed functional approach alone does not account for them. We review a simple case with a heavy scalar singlet of charge -1 to illustrate the argument. As two other examples where this matching is needed and this functional method gives a vanishing result, up to renormalization of the heavy sector parameters, we re-evaluate the one-loop corrections to the T-parameter due to a heavy scalar triplet with vanishing hypercharge coupling to the Brout-Englert-Higgs boson and to a heavy vector-like quark singlet of charged 2/3 mixing with the top quark, respectively. In all cases we make use of a new code for matching fundamental and effective theories in models with arbitrary heavy field additions. (orig.)
Secular effects on inflation from one-loop quantum gravity
International Nuclear Information System (INIS)
Cabrer, J.A.; Espriu, D.
2008-01-01
In this Letter we revisit and extend a previous analysis where the possible relevance of quantum gravity effects in a cosmological setup was studied. The object of interest are non-local (logarithmic) terms generated in the effective action of gravity due to the exchange in loops of massless modes (such as photons or the gravitons themselves). We correct one mistake existing in the previous work and discuss the issue in a more general setting in different cosmological scenarios. We obtain the one-loop quantum-corrected evolution equations for the cosmological scale factor up to a given order in a derivative expansion in two particular cases: a matter dominated universe with vanishing cosmological constant, and in a de Sitter universe. We show that the quantum corrections, albeit tiny, may have a secular effect that eventually modifies the expansion rate. For a de Sitter universe they tend to slow down the rate of the expansion, while the effect may be the opposite in a matter dominated universe
Gravitational interaction to one loop in effective quantum gravity
International Nuclear Information System (INIS)
Akhundov, A.
1996-10-01
The authors carry out the first step of a program conceived, in order to build a realistic model, having the particle spectrum of the standard model and renormalized masses, interaction terms and coupling, etc. which include the class of quantum gravity corrections, obtained by handling gravity as an effective theory. This provides an adequate picture at low energies, i.e. much less than the scale of strong gravity (the Planck mass). Hence the results are valid, irrespectively of any proposal for the full quantum gravity as a fundamental theory. The authors consider only non-analytic contributions to the one-loop scattering matrix elements, which provide the dominant quantum effect at long distance. These contributions are finite and independent from the finite value of the renormalization counter terms of the effective Lagrangian. The authors calculate the interaction of two heavy scalar particles, i.e. close to rest, due to the effective quantum gravity to the one loop order and compare with similar results in the literature
Gravitational interaction to one loop in effective quantum gravity
Energy Technology Data Exchange (ETDEWEB)
Akhundov, A. [Universitaet-gesamthochschule Siegen (Germany)]|[Azerbaijan Academy of Sciences, Baku (Azerbaijan). Institute of Physics; Bellucci, S. [INFN, Laboratori Nazionali di Frascati, Rome (Italy); Shiekh, A. [International Centre for Theoretical Physics, Trieste (Italy)
1996-10-01
The authors carry out the first step of a program conceived, in order to build a realistic model, having the particle spectrum of the standard model and renormalized masses, interaction terms and coupling, etc. which include the class of quantum gravity corrections, obtained by handling gravity as an effective theory. This provides an adequate picture at low energies, i.e. much less than the scale of strong gravity (the Planck mass). Hence the results are valid, irrespectively of any proposal for the full quantum gravity as a fundamental theory. The authors consider only non-analytic contributions to the one-loop scattering matrix elements, which provide the dominant quantum effect at long distance. These contributions are finite and independent from the finite value of the renormalization counter terms of the effective Lagrangian. The authors calculate the interaction of two heavy scalar particles, i.e. close to rest, due to the effective quantum gravity to the one loop order and compare with similar results in the literature.
One-loop potential with scale invariance and effective operators
Ghilencea, D M
2016-01-01
We study quantum corrections to the scalar potential in classically scale invariant theories, using a manifestly scale invariant regularization. To this purpose, the subtraction scale $\\mu$ of the dimensional regularization is generated after spontaneous scale symmetry breaking, from a subtraction function of the fields, $\\mu(\\phi,\\sigma)$. This function is then uniquely determined from general principles showing that it depends on the dilaton only, with $\\mu(\\sigma)\\sim \\sigma$. The result is a scale invariant one-loop potential $U$ for a higgs field $\\phi$ and dilaton $\\sigma$ that contains an additional {\\it finite} quantum correction $\\Delta U(\\phi,\\sigma)$, beyond the Coleman Weinberg term. $\\Delta U$ contains new, non-polynomial effective operators like $\\phi^6/\\sigma^2$ whose quantum origin is explained. A flat direction is maintained at the quantum level, the model has vanishing vacuum energy and the one-loop correction to the mass of $\\phi$ remains small without tuning (of its self-coupling, etc) bey...
Beyond-one-loop quantum gravity action yielding both inflation and late-time acceleration
Directory of Open Access Journals (Sweden)
E. Elizalde
2017-08-01
Full Text Available A unified description of early-time inflation with the current cosmic acceleration is achieved by means of a new theory that uses a quadratic model of gravity, with the inclusion of an exponential F(R-gravity contribution for dark energy. High-curvature corrections of the theory come from higher-derivative quantum gravity and yield an effective action that goes beyond the one-loop approximation. It is shown that, in this theory, viable inflation emerges in a natural way, leading to a spectral index and tensor-to-scalar ratio that are in perfect agreement with the most reliable Planck results. At low energy, late-time accelerated expansion takes place. As exponential gravity, for dark energy, must be stabilized during the matter and radiation eras, we introduce a curing term in order to avoid nonphysical singularities in the effective equation of state parameter. The results of our analysis are confirmed by accurate numerical simulations, which show that our model does fit the most recent cosmological data for dark energy very precisely.
The one-loop effects in the electroweak Glashow-Weinberg-Salam theory
International Nuclear Information System (INIS)
Christova Christova, P.
1987-01-01
In the near future the experiment will reach a great precision and will be able to test the standard electroweak theory. It is important now to put in order calculations of radiative corrections in this theory and to make correct and exact present theoretical predictions for the measured quantities. The survey of some results of group working in the JINR, Dubna, may serve this aim. We discuss here on-mass-shell renormalization scheme in the unitary gauge; the one-loop amplitudes of both charge and neutral currents-induced fermion scatterings; the large constant effects; the dynamical behaviour of the one-loop neutral-current corrections; the calculation of the W-and Z-boson masses; the difference between the various Weinberg parameters sin 2 Θ W . 44 refs., 10 figs., 1 tab. (author)
Effects of one-loop corrections in the Weinberg-Salam theory
International Nuclear Information System (INIS)
Bardin, D.Y.; Fedorenko, O.M.; Christova, P.C.
1982-01-01
We have studied the one-loop effects in the Weinberg-Salam theory in the natural renormalization scheme which we have generalized to the case of an arbitrary unitary mixing of the fermion fields. We have discussed in detail the problems which are connected with carrying out the renormalization program in the Weinberg-Salam theory. We have calculated the masses of the W and Z bosons. We present a description of the finite renormalizations which relate to each other the three definitions of the Weinberg parameter sin 2 theta/sub W/
Effective field theory of integrating out sfermions in the MSSM: Complete one-loop analysis
Huo, Ran
2018-04-01
We apply the covariant derivative expansion of the Coleman-Weinberg potential to the sfermion sector in the minimal supersymmetric standard model, matching it to the relevant dimension-6 operators in the standard model effective field theory at one-loop level. Emphasis is paid to nondegenerate large soft supersymmetry breaking mass squares, and the most general analytical Wilson coefficients are obtained for all pure bosonic dimension-6 operators. In addition to the non-logarithmic contributions, they generally have another logarithmic contributions. Various numerical results are shown, in particular the constraints in the large Xt branch reproducing the 125 GeV Higgs mass can be pushed to high values to almost completely probe the low stop mass region at the future FCC-ee experiment, even given the Higgs mass calculation uncertainty.
Derivative expansion of one-loop effective energy of stiff membranes with tension
Borelli, M. E. S.; Kleinert, H.; Schakel, Adriaan M. J.
1999-03-01
With help of a derivative expansion, the one-loop corrections to the energy functional of a nearly flat, stiff membrane with tension due to thermal fluctuations are calculated in the Monge parametrization. Contrary to previous studies, an arbitrary tilt of the surface is allowed to exhibit the nontrivial relations between the different, highly nonlinear terms accompanying the ultraviolet divergences. These terms are shown to have precisely the same form as those in the original energy functional, as necessary for renormalizability. Also infrared divergences arise. These, however, are shown to cancel in a nontrivial way.
One-loop effects on MSSM parameter determination via chargino production at the LC
Energy Technology Data Exchange (ETDEWEB)
Bharucha, Aoife [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Kalinowski, Jan [Warsaw Univ. (Poland). Faculty of Physics; Moortgat-Pick, Gudrid [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Rolbiecki, Krzysztof [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); IFT-UAM/CSIC, Madrid (Spain). Inst. de Fisica Teorica; Weiglein, Georg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2012-11-15
At a future linear collider very precise measurements, typically with errors of <1%, are expected to be achievable. Such an accuracy gives sensitivity to the quantum corrections, which therefore must be incorporated in theoretical calculations in order to determine the underlying new physics parameters from prospective linear collider measurements. In the context of the chargino-neutralino sector of the minimal supersymmetric standard model, this involves fitting one-loop predictions to prospective measurements of the cross sections, forward-backward asymmetries and of the accessible chargino and neutralino masses. Taking recent results from LHC SUSY and Higgs searches into account we consider three benchmark scenarios, each with characteristic features. Our analysis shows how an accurate determination of the desired parameters is possible, providing in addition access to the stop masses and mixing angle.
One-loop effects on MSSM parameter determination via chargino production at the LC
International Nuclear Information System (INIS)
Bharucha, Aoife; Rolbiecki, Krzysztof
2012-11-01
At a future linear collider very precise measurements, typically with errors of <1%, are expected to be achievable. Such an accuracy gives sensitivity to the quantum corrections, which therefore must be incorporated in theoretical calculations in order to determine the underlying new physics parameters from prospective linear collider measurements. In the context of the chargino-neutralino sector of the minimal supersymmetric standard model, this involves fitting one-loop predictions to prospective measurements of the cross sections, forward-backward asymmetries and of the accessible chargino and neutralino masses. Taking recent results from LHC SUSY and Higgs searches into account we consider three benchmark scenarios, each with characteristic features. Our analysis shows how an accurate determination of the desired parameters is possible, providing in addition access to the stop masses and mixing angle.
Grzetic, Douglas J; Delaney, Kris T; Fredrickson, Glenn H
2018-05-28
We derive the effective Flory-Huggins parameter in polarizable polymeric systems, within a recently introduced polarizable field theory framework. The incorporation of bead polarizabilities in the model self-consistently embeds dielectric response, as well as van der Waals interactions. The latter generate a χ parameter (denoted χ̃) between any two species with polarizability contrast. Using one-loop perturbation theory, we compute corrections to the structure factor Sk and the dielectric function ϵ^(k) for a polarizable binary homopolymer blend in the one-phase region of the phase diagram. The electrostatic corrections to S(k) can be entirely accounted for by a renormalization of the excluded volume parameter B into three van der Waals-corrected parameters B AA , B AB , and B BB , which then determine χ̃. The one-loop theory not only enables the quantitative prediction of χ̃ but also provides useful insight into the dependence of χ̃ on the electrostatic environment (for example, its sensitivity to electrostatic screening). The unapproximated polarizable field theory is amenable to direct simulation via complex Langevin sampling, which we employ here to test the validity of the one-loop results. From simulations of S(k) and ϵ^(k) for a system of polarizable homopolymers, we find that the one-loop theory is best suited to high concentrations, where it performs very well. Finally, we measure χ̃N in simulations of a polarizable diblock copolymer melt and obtain excellent agreement with the one-loop theory. These constitute the first fully fluctuating simulations conducted within the polarizable field theory framework.
Study of open-charm 0{sup +} states in unitarized chiral effective theory with one-loop potentials
Energy Technology Data Exchange (ETDEWEB)
Du, Meng-Lin [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Bonn (Germany); Guo, Feng-Kun [Chinese Academy of Sciences, CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Beijing (China); University of Chinese Academy of Sciences, School of Physical Sciences, Beijing (China); Meissner, Ulf G. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Bonn (Germany); Forschungszentrum Juelich, Institute for Advanced Simulation, Institut fuer Kernphysik and Juelich Center for Hadron Physics (Germany); Yao, De-Liang [Forschungszentrum Juelich, Institute for Advanced Simulation, Institut fuer Kernphysik and Juelich Center for Hadron Physics (Germany); Instituto de Fisica Corpuscular (Centro mixto CSIC-UV), Institutos de Investigacion de Paterna, Valencia (Spain)
2017-11-15
Chiral potentials are derived for the interactions between Goldstone bosons and pseudo-scalar charmed mesons up to next-to-next-to-leading order in a covariant chiral effective field theory with explicit vector charmed-meson degrees of freedom. Using the extended-on-mass-shell scheme, we demonstrate that the ultraviolet divergences and the so-called power counting breaking terms can be properly absorbed by the low-energy constants of the chiral Lagrangians. We calculate the scattering lengths by unitarizing the one-loop potentials and fit them to the data extracted from lattice QCD. The obtained results are compared to the ones without an explicit contribution of vector charmed mesons given previously. It is found that the difference is negligible for S-wave scattering in the threshold region. This validates the use of D*-less one-loop potentials in the study of the pertinent scattering lengths. We search for dynamically generated open-charm states with J{sup P} = 0{sup +} as poles of the S-matrix on various Riemann sheets. The trajectories of those poles for varying pion masses are presented as well. (orig.)
One-loop effect of null-like cosmology's holographic dual super-Yang-Mills
International Nuclear Information System (INIS)
Lin, F.-L.; Tomino, Dan
2007-01-01
We calculate the 1-loop effect in super-Yang-Mills which preserves 1/4-supersymmetries and is holographically dual to the null-like cosmology with a big-bang singularity. Though the bosonic and fermionic spectra do not agree precisely, we do obtain vanishing 1-loop vacuum energy for generic warped plane-wave type backgrounds with a big-bang singularity. Moreover, we find that the cosmological 'constant' contributed either by bosons or fermions is time-dependent. The issues about the particle production of some background and about the UV structure are also commented. We argue that the effective higher derivative interactions are suppressed as long as the Fourier transform of the time-dependent coupling is UV-finite. Our result holds for scalar configurations that are BPS but with arbitrary time-dependence. This suggests the existence of non-renormalization theorem for such a new class of time-dependent theories. Altogether, it implies that such a super-Yang-Mills is scale-invariant, and that its dual bulk quantum gravity might behave regularly near the big bang
One-loop effects on top pair production in the littlest Higgs model with T-parity at the LHC
International Nuclear Information System (INIS)
Yang, Bingfang; Liu, Ning
2013-01-01
In this work, we systematically investigate the one-loop corrections to t anti t production in the littlest Higgs model with T-parity (LHT) at the LHC for √(s) = 8,14 TeV. We focus on the effects of LHT particles on t anti t cross section, polarization asymmetries, spin correlation and charge asymmetry at the LHC. We also study the top quark forward-backward asymmetry at Tevatron and its correlations with the LHC observables. We found that: (1) the contributions of the LHT particles to t anti t production can only reach about 1 % at the 14 TeV LHC. Meanwhile, the anomalous top quark forward-backward asymmetry at Tevatron is also hardly to be explained in the LHT model. (2) The parity violating asymmetries in t anti t production, such as left-right asymmetry vertical stroke A LR vertical stroke and the polarization vertical stroke P t vertical stroke can, respectively, reach 1.1 % and 0.5 %, which may have the potential to provide a signal of LHT at the LHC. (orig.)
One-loop matching and running with covariant derivative expansion
Henning, Brian; Lu, Xiaochuan; Murayama, Hitoshi
2018-01-01
We develop tools for performing effective field theory (EFT) calculations in a manifestly gauge-covariant fashion. We clarify how functional methods account for one-loop diagrams resulting from the exchange of both heavy and light fields, as some confusion has recently arisen in the literature. To efficiently evaluate functional traces containing these "mixed" one-loop terms, we develop a new covariant derivative expansion (CDE) technique that is capable of evaluating a much wider class of traces than previous methods. The technique is detailed in an appendix, so that it can be read independently from the rest of this work. We review the well-known matching procedure to one-loop order with functional methods. What we add to this story is showing how to isolate one-loop terms coming from diagrams involving only heavy propagators from diagrams with mixed heavy and light propagators. This is done using a non-local effective action, which physically connects to the notion of "integrating out" heavy fields. Lastly, we show how to use a CDE to do running analyses in EFTs, i.e. to obtain the anomalous dimension matrix. We demonstrate the methodologies by several explicit example calculations.
One-loop divergences in 6D, N=(1,0) SYM theory
Energy Technology Data Exchange (ETDEWEB)
Buchbinder, I.L. [Department of Theoretical Physics, Tomsk State Pedagogical University,634061, Tomsk (Russian Federation); National Research Tomsk State University,634050, Tomsk (Russian Federation); Ivanov, E.A. [Bogoliubov Laboratory of Theoretical Physics,JINR, 141980 Dubna, Moscow region (Russian Federation); Merzlikin, B.S. [Department of Theoretical Physics, Tomsk State Pedagogical University,634061, Tomsk (Russian Federation); Department of Higher Mathematics and Mathematical Physics,Tomsk Polytechnic University,634050, Tomsk (Russian Federation); Stepanyantz, K.V. [Department of Theoretical Physics, Moscow State University,119991, Moscow (Russian Federation)
2017-01-30
We consider, in the harmonic superspace approach, the six-dimensional N=(1,0) supersymmetric Yang-Mills gauge multiplet minimally coupled to a hypermultiplet in an arbitrary representation of the gauge group. Using the superfield proper-time and background-field techniques, we compute the divergent part of the one-loop effective action depending on both the gauge multiplet and the hypermultiplet. We demonstrate that in the particular case of N=(1,1) SYM theory, which corresponds to the hypermultiplet in the adjoint representation, all one-loop divergencies vanish, so that N=(1,1) SYM theory is one-loop finite off shell.
Covariant diagrams for one-loop matching
International Nuclear Information System (INIS)
Zhang, Zhengkang
2016-10-01
We present a diagrammatic formulation of recently-revived covariant functional approaches to one-loop matching from an ultraviolet (UV) theory to a low-energy effective field theory. Various terms following from a covariant derivative expansion (CDE) are represented by diagrams which, unlike conventional Feynman diagrams, involve gaugecovariant quantities and are thus dubbed ''covariant diagrams.'' The use of covariant diagrams helps organize and simplify one-loop matching calculations, which we illustrate with examples. Of particular interest is the derivation of UV model-independent universal results, which reduce matching calculations of specific UV models to applications of master formulas. We show how such derivation can be done in a more concise manner than the previous literature, and discuss how additional structures that are not directly captured by existing universal results, including mixed heavy-light loops, open covariant derivatives, and mixed statistics, can be easily accounted for.
Covariant diagrams for one-loop matching
Energy Technology Data Exchange (ETDEWEB)
Zhang, Zhengkang [Michigan Center for Theoretical Physics (MCTP), University of Michigan,450 Church Street, Ann Arbor, MI 48109 (United States); Deutsches Elektronen-Synchrotron (DESY),Notkestraße 85, 22607 Hamburg (Germany)
2017-05-30
We present a diagrammatic formulation of recently-revived covariant functional approaches to one-loop matching from an ultraviolet (UV) theory to a low-energy effective field theory. Various terms following from a covariant derivative expansion (CDE) are represented by diagrams which, unlike conventional Feynman diagrams, involve gauge-covariant quantities and are thus dubbed “covariant diagrams.” The use of covariant diagrams helps organize and simplify one-loop matching calculations, which we illustrate with examples. Of particular interest is the derivation of UV model-independent universal results, which reduce matching calculations of specific UV models to applications of master formulas. We show how such derivation can be done in a more concise manner than the previous literature, and discuss how additional structures that are not directly captured by existing universal results, including mixed heavy-light loops, open covariant derivatives, and mixed statistics, can be easily accounted for.
Covariant diagrams for one-loop matching
Energy Technology Data Exchange (ETDEWEB)
Zhang, Zhengkang [Michigan Univ., Ann Arbor, MI (United States). Michigan Center for Theoretical Physics; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2016-10-15
We present a diagrammatic formulation of recently-revived covariant functional approaches to one-loop matching from an ultraviolet (UV) theory to a low-energy effective field theory. Various terms following from a covariant derivative expansion (CDE) are represented by diagrams which, unlike conventional Feynman diagrams, involve gaugecovariant quantities and are thus dubbed ''covariant diagrams.'' The use of covariant diagrams helps organize and simplify one-loop matching calculations, which we illustrate with examples. Of particular interest is the derivation of UV model-independent universal results, which reduce matching calculations of specific UV models to applications of master formulas. We show how such derivation can be done in a more concise manner than the previous literature, and discuss how additional structures that are not directly captured by existing universal results, including mixed heavy-light loops, open covariant derivatives, and mixed statistics, can be easily accounted for.
Covariant diagrams for one-loop matching
International Nuclear Information System (INIS)
Zhang, Zhengkang
2017-01-01
We present a diagrammatic formulation of recently-revived covariant functional approaches to one-loop matching from an ultraviolet (UV) theory to a low-energy effective field theory. Various terms following from a covariant derivative expansion (CDE) are represented by diagrams which, unlike conventional Feynman diagrams, involve gauge-covariant quantities and are thus dubbed “covariant diagrams.” The use of covariant diagrams helps organize and simplify one-loop matching calculations, which we illustrate with examples. Of particular interest is the derivation of UV model-independent universal results, which reduce matching calculations of specific UV models to applications of master formulas. We show how such derivation can be done in a more concise manner than the previous literature, and discuss how additional structures that are not directly captured by existing universal results, including mixed heavy-light loops, open covariant derivatives, and mixed statistics, can be easily accounted for.
Gluon quasidistribution function at one loop
Energy Technology Data Exchange (ETDEWEB)
Wang, Wei; Zhao, Shuai [Shanghai Jiao Tong University, INPAC, Shanghai Key Laboratory for Particle Physics and Cosmology, School of Physics and Astronomy, Shanghai (China); Zhu, Ruilin [Shanghai Jiao Tong University, INPAC, Shanghai Key Laboratory for Particle Physics and Cosmology, School of Physics and Astronomy, Shanghai (China); Nanjing Normal University, Department of Physics and Institute of Theoretical Physics, Nanjing, Jiangsu (China)
2018-02-15
We study the unpolarized gluon quasidistribution function in the nucleon at one loop level in the large momentum effective theory. For the quark quasidistribution, power law ultraviolet divergences arise in the cut-off scheme and an important observation is that they all are subjected to Wilson lines. However for the gluon quasidistribution function, we first point out that the linear ultraviolet divergences also exist in the real diagram which is not connected to any Wilson line. We then study the one loop corrections to parton distribution functions in both cut-off scheme and dimensional regularization to deal with the ultraviolet divergences. In addition to the ordinary quark and gluon distributions, we also include the quark to gluon and gluon to quark splitting diagrams. The complete one-loop matching factors between the quasi and light cone parton distribution functions are presented in the cut-off scheme. We derive the P{sup z} evolution equation for quasi parton distribution functions, and find that the P{sup z} evolution kernels are identical to the DGLAP evolution kernels. (orig.)
One-loop partition functions of 3D gravity
International Nuclear Information System (INIS)
Giombi, Simone; Yin Xi; Maloney, Alexander
2008-01-01
We consider the one-loop partition function of free quantum field theory in locally Anti-de Sitter space-times. In three dimensions, the one loop determinants for scalar, gauge and graviton excitations are computed explicitly using heat kernel techniques. We obtain precisely the result anticipated by Brown and Henneaux: the partition function includes a sum over 'boundary excitations' of AdS 3 , which are the Virasoro descendants of empty Anti-de Sitter space. This result also allows us to compute the one-loop corrections to the Euclidean action of the BTZ black hole as well its higher genus generalizations.
Constructing QCD one-loop amplitudes
International Nuclear Information System (INIS)
Forde, D
2008-01-01
In the context of constructing one-loop amplitudes using a unitarity bootstrap approach we discuss a general systematic procedure for obtaining the coefficients of the scalar bubble and triangle integral functions of one-loop amplitudes. Coefficients are extracted after examining the behavior of the cut integrand as the unconstrained parameters of a specifically chosen parameterization of the cut loop momentum approach infinity. Measurements of new physics at the forthcoming experimental program at CERN's Large Hadron Collider (LHC) will require a precise understanding of processes at next-to-leading order (NLO). This places increased demands for the computation of new one-loop amplitudes. This in turn has spurred recent developments towards improved calculational techniques. Direct calculations using Feynman diagrams are in general inefficient. Developments of more efficient techniques have usually centered around unitarity techniques [1], where tree amplitudes are effectively 'glued' together to form loops. The most straightforward application of this method, in which the cut loop momentum is in D = 4, allows for the computation of 'cut-constructible' terms only, i.e. (poly)logarithmic containing terms and any related constants. QCD amplitudes contain, in addition to such terms, rational pieces which cannot be derived using such cuts. These 'missing' rational parts can be extracted using cut loop momenta in D = 4-2 (var e psilon). The greater difficulty of such calculations has restricted the application of this approach, although recent developments [3, 4] have provided new promise for this technique. Recently the application of on-shell recursion relations [5] to obtaining the 'missing' rational parts of one-loop processes [6] has provided an alternative very promising solution to this problem. In combination with unitarity methods an 'on-shell bootstrap' approach provides an efficient technique for computing complete one-loop QCD amplitudes [7]. Additionally
Zeta Functions, Renormalization Group Equations, and the Effective Action
International Nuclear Information System (INIS)
Hochberg, D.; Perez-Mercader, J.; Molina-Paris, C.; Visser, M.
1998-01-01
We demonstrate how to extract all the one-loop renormalization group equations for arbitrary quantum field theories from knowledge of an appropriate Seeley-DeWitt coefficient. By formally solving the renormalization group equations to one loop, we renormalization group improve the classical action and use this to derive the leading logarithms in the one-loop effective action for arbitrary quantum field theories. copyright 1998 The American Physical Society
Numerical approach to one-loop integrals
International Nuclear Information System (INIS)
Fujimoto, Junpei; Shimizu, Yoshimitsu; Kato, Kiyoshi; Oyanagi, Yoshio.
1992-01-01
Two numerical methods are proposed for the calculation of one-loop scalar integrals. In the first method, the singularity is cancelled by the symmetrization of the integrand and the integration is done by a Monte-Carlo method. In the second one, after the transform of the integrand into a standard form, the integral is reduced into a regular numerical integral. These methods provide us practical tools to evaluate one-loop Feynman diagrams with desired numerical accuracy. They are extended to the integral with numerator and the treatment of the one-loop virtual correction to the cross section is also presented. (author)
One-loop Pfaffians and large-field inflation in string theory
Energy Technology Data Exchange (ETDEWEB)
Ruehle, Fabian, E-mail: fabian.ruehle@physics.ox.ac.uk [Rudolf Peierls Centre for Theoretical Physics, Oxford University, 1 Keble Road, Oxford, OX1 3NP (United Kingdom); Wieck, Clemens, E-mail: clemens.wieck@uam.es [Departamento de Física Teórica and Instituto de Física Teórica UAM/CSIC, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid (Spain)
2017-06-10
We study the consistency of large-field inflation in low-energy effective field theories of string theory. In particular, we focus on the stability of Kähler moduli in the particularly interesting case where the non-perturbative superpotential of the Kähler sector explicitly depends on the inflaton field. This situation arises generically due to one-loop corrections to the instanton action. The field dependence of the modulus potential feeds back into the inflationary dynamics, potentially impairing slow roll. We distinguish between world-sheet instantons from Euclidean D-branes, which typically yield polynomial one-loop Pfaffians, and gaugino condensates, which can yield exponential or periodic corrections. In all scenarios successful slow-roll inflation imposes bounds on the magnitude of the one-loop correction, corresponding to constraints on possible compactifications. While we put a certain emphasis on Type IIB constructions with mobile D7-branes, our results seem to apply more generally.
One-loop calculations with massive particles
International Nuclear Information System (INIS)
Oldenborgh, G.J. van.
1990-01-01
In this thesis some techniques for performing one-loop calculations with massive particles are presented. Numerical techniques are presented necessary for evaluating one-loop integrals which occur in one-loop calculations of photon-photon scattering. The algorithms have been coded in FORTRAN (to evaluate the scalar integrals) and the algebraic language FORM (to reduce the tensor integrals to scalar integrals). Applications are made in the theory of the strong interaction, QCD, i.e. in handling one-loop integrals with massive particles, in order to regulate the infinities by mass parameters encountered in this theory. However this simplifies the computation considerably, the description of the proton structure functions have to be renormalized in order to obtain physical results. This renormalization is different from the published results for the gluon and thus has to be redone. The first physics results that have been obtained with these new methods are presented. These concern heavy quark production in semi-leptonic interactions, for instance neutrino charm production and top production at the electron-proton (ep) collider HERA and the proposed LEP/LHC combination. Total and differential cross-sections for one-loop corrections to top production at the HERA and proposed LEP/HLC ep colliders are given and structure functions for charmed quark production are compared with previously published results. (author). 58 refs.; 18 figs.; 5 tabs
Quenched Chiral Perturbation Theory to one loop
Colangelo, G.; Pallante, E.
The divergences of the generating functional of quenched Chiral Perturbation theory (qCHPT) to one loop are computed in closed form. We show how the quenched chiral logarithms can be reabsorbed in the renormalization of the B0 parameter of the leading order Lagrangian. Finally, we do the chiral
Local expressions for one-loop calculations
International Nuclear Information System (INIS)
Wasson, D.A.; Koonin, S.E.
1991-01-01
We develop local expressions for the contributions of the short-wavelength vacuum modes to the one-loop vacuum energy. These expressions significantly improve the convergence properties of various ''brute-force'' calculational methods. They also provide a continuous series of approximations that interpolate between the brute-force calculations and the derivative expansion
On the One Loop Corrections to Inflation II
DEFF Research Database (Denmark)
Sloth, Martin Snoager
2006-01-01
In this paper we extend our previous treatment of the one-loop corrections to inflation. Previously we calculated the one-loop corrections to the background and the two-point correlation function of inflaton fluctuations in a specific model of chaotic inflation. We showed that the loop correction...... model of chaotic inflation with a quadratic inflationary potential. We discuss the physical interpretation of the effect in terms of the tensor-to-scalar consistency relation. Finally, we discuss the relation to the work of Weinberg on quantum contributions to cosmological correlators....
Scalar one-loop integrals for QCD
International Nuclear Information System (INIS)
Ellis, R. Keith; Zanderighi, Giulia
2008-01-01
We construct a basis set of infra-red and/or collinearly divergent scalar one-loop integrals and give analytic formulas, for tadpole, bubble, triangle and box integrals, regulating the divergences (ultra-violet, infra-red or collinear) by regularization in D = 4-2ε dimensions. For scalar triangle integrals we give results for our basis set containing 6 divergent integrals. For scalar box integrals we give results for our basis set containing 16 divergent integrals. We provide analytic results for the 5 divergent box integrals in the basis set which are missing in the literature. Building on the work of van Oldenborgh, a general, publicly available code has been constructed, which calculates both finite and divergent one-loop integrals. The code returns the coefficients of 1/ε 2 ,1/ε 1 and 1/ε 0 as complex numbers for an arbitrary tadpole, bubble, triangle or box integral
Automated one-loop calculations with GOSAM
International Nuclear Information System (INIS)
Cullen, Gavin; Greiner, Nicolas; Heinrich, Gudrun; Reiter, Thomas; Luisoni, Gionata
2011-11-01
We present the program package GoSam which is designed for the automated calculation of one-loop amplitudes for multi-particle processes in renormalisable quantum field theories. The amplitudes, which are generated in terms of Feynman diagrams, can be reduced using either D-dimensional integrand-level decomposition or tensor reduction. GoSam can be used to calculate one-loop QCD and/or electroweak corrections to Standard Model processes and offers the flexibility to link model files for theories Beyond the Standard Model. A standard interface to programs calculating real radiation is also implemented. We demonstrate the flexibility of the program by presenting examples of processes with up to six external legs attached to the loop. (orig.)
Automated one-loop calculations with GOSAM
Energy Technology Data Exchange (ETDEWEB)
Cullen, Gavin [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Deutsches Elektronen-Synchrotron, Zeuthen [DESY; Germany; Greiner, Nicolas [Illinois Univ., Urbana-Champaign, IL (United States). Dept. of Physics; Max-Planck-Institut fuer Physik, Muenchen (Germany); Heinrich, Gudrun; Reiter, Thomas [Max-Planck-Institut fuer Physik, Muenchen (Germany); Luisoni, Gionata [Durham Univ. (United Kingdom). Inst. for Particle Physics Phenomenology; Mastrolia, Pierpaolo [Max-Planck-Institut fuer Physik, Muenchen (Germany); Padua Univ. (Italy). Dipt. di Fisica; Ossola, Giovanni [New York City Univ., NY (United States). New York City College of Technology; New York City Univ., NY (United States). The Graduate School and University Center; Tramontano, Francesco [European Organization for Nuclear Research (CERN), Geneva (Switzerland)
2011-11-15
We present the program package GoSam which is designed for the automated calculation of one-loop amplitudes for multi-particle processes in renormalisable quantum field theories. The amplitudes, which are generated in terms of Feynman diagrams, can be reduced using either D-dimensional integrand-level decomposition or tensor reduction. GoSam can be used to calculate one-loop QCD and/or electroweak corrections to Standard Model processes and offers the flexibility to link model files for theories Beyond the Standard Model. A standard interface to programs calculating real radiation is also implemented. We demonstrate the flexibility of the program by presenting examples of processes with up to six external legs attached to the loop. (orig.)
Automation of one-loop QCD corrections
Hirschi, Valentin; Frixione, Stefano; Garzelli, Maria Vittoria; Maltoni, Fabio; Pittau, Roberto
2011-01-01
We present the complete automation of the computation of one-loop QCD corrections, including UV renormalization, to an arbitrary scattering process in the Standard Model. This is achieved by embedding the OPP integrand reduction technique, as implemented in CutTools, into the MadGraph framework. By interfacing the tool so constructed, which we dub MadLoop, with MadFKS, the fully automatic computation of any infrared-safe observable at the next-to-leading order in QCD is attained. We demonstrate the flexibility and the reach of our method by calculating the production rates for a variety of processes at the 7 TeV LHC.
Polynomial structures in one-loop amplitudes
International Nuclear Information System (INIS)
Britto, Ruth; Feng Bo; Yang Gang
2008-01-01
A general one-loop scattering amplitude may be expanded in terms of master integrals. The coefficients of the master integrals can be obtained from tree-level input in a two-step process. First, use known formulas to write the coefficients of (4-2ε)-dimensional master integrals; these formulas depend on an additional variable, u, which encodes the dimensional shift. Second, convert the u-dependent coefficients of (4-2ε)-dimensional master integrals to explicit coefficients of dimensionally shifted master integrals. This procedure requires the initial formulas for coefficients to have polynomial dependence on u. Here, we give a proof of this property in the case of massless propagators. The proof is constructive. Thus, as a byproduct, we produce different algebraic expressions for the scalar integral coefficients, in which the polynomial property is apparent. In these formulas, the box and pentagon contributions are separated explicitly.
One-loop Yukawa Couplings in Local Models
Conlon, Joseph P; Palti, Eran; 10.1007
2010-01-01
We calculate the one-loop Yukawa couplings and threshold corrections for supersymmetric local models of branes at singularities in type IIB string theory. We compute the corrections coming both from wavefunction and vertex renormalisation. The former comes in the IR from conventional field theory running and in the UV from threshold corrections that cause it to run from the winding scale associated to the full Calabi-Yau volume. The vertex correction is naively absent as it appears to correspond to superpotential renormalisation. However, we find that while the Wilsonian superpotential is not renormalised there is a physical vertex correction in the 1PI action associated to light particle loops.
One-loop Yukawa couplings in local models
Energy Technology Data Exchange (ETDEWEB)
Conlon, Joseph P. [Rudolf Peierls Center for Theoretical Physics, Oxford (United Kingdom); Balliol College, Oxford (United Kingdom); Goodsell, Mark [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Palti, Eran [Centre de Physique Theorique, Ecole Polytechnique, CNRS, Palaiseau (France)
2010-07-15
We calculate the one-loop Yukawa couplings and threshold corrections for supersymmetric local models of branes at singularities in type IIB string theory. We compute the corrections coming both from wavefunction and vertex renormalisation. The former comes in the IR from conventional field theory running and in the UV from threshold corrections that cause it to run from the winding scale associated to the full Calabi-Yau volume. The vertex correction is naively absent as it appears to correspond to superpotential renormalisation. However, we find that while the Wilsonian superpotential is not renormalised there is a physical vertex correction in the 1PI action associated to light particle loops. (orig.)
One-loop Yukawa couplings in local models
International Nuclear Information System (INIS)
Conlon, Joseph P.; Goodsell, Mark; Palti, Eran
2010-07-01
We calculate the one-loop Yukawa couplings and threshold corrections for supersymmetric local models of branes at singularities in type IIB string theory. We compute the corrections coming both from wavefunction and vertex renormalisation. The former comes in the IR from conventional field theory running and in the UV from threshold corrections that cause it to run from the winding scale associated to the full Calabi-Yau volume. The vertex correction is naively absent as it appears to correspond to superpotential renormalisation. However, we find that while the Wilsonian superpotential is not renormalised there is a physical vertex correction in the 1PI action associated to light particle loops. (orig.)
One-loop dimensional reduction of the linear σ model
International Nuclear Information System (INIS)
Malbouisson, A.P.C.; Silva-Neto, M.B.; Svaiter, N.F.
1997-05-01
We perform the dimensional reduction of the linear σ model at one-loop level. The effective of the reduced theory obtained from the integration over the nonzero Matsubara frequencies is exhibited. Thermal mass and coupling constant renormalization constants are given, as well as the thermal renormalization group which controls the dependence of the counterterms on the temperature. We also recover, for the reduced theory, the vacuum instability of the model for large N. (author)
Effective action for stochastic partial differential equations
International Nuclear Information System (INIS)
Hochberg, David; Molina-Paris, Carmen; Perez-Mercader, Juan; Visser, Matt
1999-01-01
Stochastic partial differential equations (SPDEs) are the basic tool for modeling systems where noise is important. SPDEs are used for models of turbulence, pattern formation, and the structural development of the universe itself. It is reasonably well known that certain SPDEs can be manipulated to be equivalent to (nonquantum) field theories that nevertheless exhibit deep and important relationships with quantum field theory. In this paper we systematically extend these ideas: We set up a functional integral formalism and demonstrate how to extract all the one-loop physics for an arbitrary SPDE subject to arbitrary Gaussian noise. It is extremely important to realize that Gaussian noise does not imply that the field variables undergo Gaussian fluctuations, and that these nonquantum field theories are fully interacting. The limitation to one loop is not as serious as might be supposed: Experience with quantum field theories (QFTs) has taught us that one-loop physics is often quite adequate to give a good description of the salient issues. The limitation to one loop does, however, offer marked technical advantages: Because at one loop almost any field theory can be rendered finite using zeta function technology, we can sidestep the complications inherent in the Martin-Siggia-Rose formalism (the SPDE analog of the Becchi-Rouet-Stora-Tyutin formalism used in QFT) and instead focus attention on a minimalist approach that uses only the physical fields (this ''direct approach'' is the SPDE analog of canonical quantization using physical fields). After setting up the general formalism for the characteristic functional (partition function), we show how to define the effective action to all loops, and then focus on the one-loop effective action and its specialization to constant fields: the effective potential. The physical interpretation of the effective action and effective potential for SPDEs is addressed and we show that key features carry over from QFT to the case of
Effective action for stochastic partial differential equations
Energy Technology Data Exchange (ETDEWEB)
Hochberg, David [Laboratorio de Astrofisica Espacial y Fisica Fundamental, Apartado 50727, 28080 Madrid, (Spain); Centro de Astrobiologia, INTA, Carratera Ajalvir, Km. 4, 28850 Torrejon, Madrid, (Spain); Molina-Paris, Carmen [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Perez-Mercader, Juan [Laboratorio de Astrofisica Espacial y Fisica Fundamental, Apartado 50727, 28080 Madrid, (Spain); Visser, Matt [Physics Department, Washington University, Saint Louis, Missouri 63130-4899 (United States)
1999-12-01
Stochastic partial differential equations (SPDEs) are the basic tool for modeling systems where noise is important. SPDEs are used for models of turbulence, pattern formation, and the structural development of the universe itself. It is reasonably well known that certain SPDEs can be manipulated to be equivalent to (nonquantum) field theories that nevertheless exhibit deep and important relationships with quantum field theory. In this paper we systematically extend these ideas: We set up a functional integral formalism and demonstrate how to extract all the one-loop physics for an arbitrary SPDE subject to arbitrary Gaussian noise. It is extremely important to realize that Gaussian noise does not imply that the field variables undergo Gaussian fluctuations, and that these nonquantum field theories are fully interacting. The limitation to one loop is not as serious as might be supposed: Experience with quantum field theories (QFTs) has taught us that one-loop physics is often quite adequate to give a good description of the salient issues. The limitation to one loop does, however, offer marked technical advantages: Because at one loop almost any field theory can be rendered finite using zeta function technology, we can sidestep the complications inherent in the Martin-Siggia-Rose formalism (the SPDE analog of the Becchi-Rouet-Stora-Tyutin formalism used in QFT) and instead focus attention on a minimalist approach that uses only the physical fields (this ''direct approach'' is the SPDE analog of canonical quantization using physical fields). After setting up the general formalism for the characteristic functional (partition function), we show how to define the effective action to all loops, and then focus on the one-loop effective action and its specialization to constant fields: the effective potential. The physical interpretation of the effective action and effective potential for SPDEs is addressed and we show that key features carry over from
Numerical evaluation of one-loop QCD amplitudes
DEFF Research Database (Denmark)
Badger, Simon David; Biedermann, Benedikt; Uwer, Peter
2012-01-01
We present the publicly available program NGluon allowing the numerical evaluation of primitive amplitudes at one-loop order in massless QCD. The program allows the computation of one-loop amplitudes for an arbitrary number of gluons. The focus of the present article is the extension to one-loop ...
One-loop lattice artifacts of a dynamical charm quark
Energy Technology Data Exchange (ETDEWEB)
Athenodorou, Andreas; Sommer, Rainer [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2011-10-15
For a few observables in O(a) improved lattice QCD, we compute discretization effects arising from the vacuum polarization of a heavy quark at one-loop order. In particular, the force between static quarks, the running coupling in the Schroedinger functional and a related quantity, anti {upsilon}, are considered. Results show that the cutoff effects of a dynamical charm quark are typically smaller than those present in the pure gauge theory. This perturbative result is a good indication that dynamical charm quarks are feasible already now. (orig.)
One-loop lattice artifacts of a dynamical charm quark
International Nuclear Information System (INIS)
Athenodorou, Andreas; Sommer, Rainer
2011-10-01
For a few observables in O(a) improved lattice QCD, we compute discretization effects arising from the vacuum polarization of a heavy quark at one-loop order. In particular, the force between static quarks, the running coupling in the Schroedinger functional and a related quantity, anti υ, are considered. Results show that the cutoff effects of a dynamical charm quark are typically smaller than those present in the pure gauge theory. This perturbative result is a good indication that dynamical charm quarks are feasible already now. (orig.)
Effective action for scalar fields and generalized zeta-function regularization
International Nuclear Information System (INIS)
Cognola, Guido; Zerbini, Sergio
2004-01-01
Motivated by the study of quantum fields in a Friedmann-Robertson-Walker space-time, the one-loop effective action for a scalar field defined in the ultrastatic manifold RxH 3 /Γ, H 3 /Γ being the finite volume, noncompact, hyperbolic spatial section, is investigated by a generalization of zeta-function regularization. It is shown that additional divergences may appear at the one-loop level. The one-loop renormalizability of the model is discussed and, making use of a generalization of zeta-function regularization, the one-loop renormalization group equations are derived
SUSY non-Abelian gauge models: exact beta function from one loop of perturbation theory
International Nuclear Information System (INIS)
Shifman, M.A.; Vajnshtejn, A.I.; Zakharov, V.I.
1985-01-01
The method for calculating the exact β function (to all orders in the coupling constant) proposed earlier in supersymmetric electrodynamics is extended. The starting point is the observation that the low-energy effective action is exhausted by one loop provided that the theory is regularized supersymmetrically both in the ultraviolet and infrared domains in four dimensions. The Pouli-Villars method of the ultraviolet regularization is used. Two methods for the infrared regularization are considered. The first one - quantization in a box with a finite volume L 3 - is universally applicable to anygauge theory. The second method is based on the effective Higgs mechanism for mass generation and requires the presence of certain matter superfields in the lagrangian. Within this method the necessary condition is the existence of flat directions, so called valeys, along which the vacuum energy vanishes. The theory is quantized near epsilon non-vanishing value of the scalar field from the bottom of the valley. After calculating the one-loop effective action one and the same exact expression is obtained for the β function within the both approaches, and it also coincides with our earlier result extracted from instanton calculus. A few remarks on the problem of anomalies in SUSY gauge theories are presented
One loop back reaction on power law inflation
International Nuclear Information System (INIS)
Abramo, L.R.; Woodard, R.P.
1999-01-01
We consider quantum-mechanical corrections to a homogeneous, isotropic, and spatially flat geometry whose scale factor expands classically as a general power of the comoving time. The effects of both gravitons and the scalar inflaton are computed at one loop using the manifestly causal formalism of Schwinger [J. Math. Phys. 2, 407 (1961); Particles, Sources and Fields (Addison, Wesley, Reading, MA, 1970)] with the Feynman rules recently developed by Iliopoulos et al. [Nucl. Phys. B 534, 419 (1998)]. We find no significant effect, in marked contrast to the result obtained by Mukhanov and co-workers [Phys. Rev. Lett. 78, 1624 (1998); Phys. Rev. D 56, 3248 (1997)] for chaotic inflation based on a quadratic potential. By applying the canonical technique of Mukhanov and co-workers to the exponential potentials of power law inflation, we show that the two methods produce the same results, within the approximations employed, for these backgrounds. We therefore conclude that the shape of the inflaton potential can have an enormous impact on the one loop back reaction. copyright 1999 The American Physical Society
Effective 1.0: An Analytic Effective Action Analysis Library
Hetherington, James P. J.; Stephens, Philip
2006-01-01
Effective is a C++ library which provides the user a toolbox to study the effective action of an arbitrary field theory. From the field content, gauge groups and representations an appropriate action is generated symbolically. The effective potential, mass spectrum, field couplings and vacuum expectation values are then obtained automatically; tree level results are obtained analytically while many tools, both numeric and analytic, provide a variety of approaches to deal with the one-loop cor...
The five-gluon amplitude and one-loop integrals
International Nuclear Information System (INIS)
Bern, Z.; Dixon, L.; Kosower, D.A.
1992-12-01
We review the conventional field theory description of the string motivated technique. This technique is applied to the one-loop five-gluon amplitude. To evaluate the amplitude a general method for computing dimensionally regulated one-loop integrals is outlined including results for one-loop integrals required for the pentagon diagram and beyond. Finally, two five-gluon helicity amplitudes are given
One-loop perturbative coupling of A and A? through the chiral overlap operator
Makino, Hiroki; Morikawa, Okuto; Suzuki, Hiroshi
2018-03-01
Recently, Grabowska and Kaplan constructed a four-dimensional lattice formulation of chiral gauge theories on the basis of the chiral overlap operator. At least in the tree-level approximation, the left-handed fermion is coupled only to the original gauge field A, while the right-handed one is coupled only to the gauge field A*, a deformation of A by the gradient flow with infinite flow time. In this paper, we study the fermion one-loop effective action in their formulation. We show that the continuum limit of this effective action contains local interaction terms between A and A*, even if the anomaly cancellation condition is met. These non-vanishing terms would lead an undesired perturbative spectrum in the formulation.
FF. A package to evaluate one-loop Feynman diagrams
International Nuclear Information System (INIS)
Oldenborgh, G.J. van
1990-09-01
A short description and a user's guide of the FF package are given. This package contains routines to evaluate numerically the scalar one-loop integrals occurring in the evaluation in one-loop Feynman diagrams. The algorithms chosen are numerically stable over most parameter space. (author). 5 refs.; 1 tab
Automated computation of one-loop integrals in massless theories
International Nuclear Information System (INIS)
Hameren, A. van; Vollinga, J.; Weinzierl, S.
2005-01-01
We consider one-loop tensor and scalar integrals, which occur in a massless quantum field theory, and we report on the implementation into a numerical program of an algorithm for the automated computation of these one-loop integrals. The number of external legs of the loop integrals is not restricted. All calculations are done within dimensional regularization. (orig.)
The running coupling from the QCD Schrödinger functional a one-loop analysis
Sint, S; Sint, Stefan; Sommer, Rainer
1996-01-01
Starting from the Schr\\"odinger functional, we give a non-perturbative definition of the running coupling constant in QCD. The spatial boundary conditions for the quark fields are chosen such that the massless Dirac operator in the classical background field has a large smallest eigenvalue. At one-loop order of perturbation theory, we determine the matching coefficient to the \\MSbar-scheme and discuss the quark mass effects in the \\beta-function. To this order, we also compute the Symanzik improvement coefficient necessary to remove the \\Oa lattice artefacts originating from the boundaries. For reasonable lattice resolutions and the standard Wilson action, lattice artefacts are found to be only weakly dependent on the lattice spacing a, while they vanish quickly with the improved action of Sheikholeslami and Wohlert.
Invariant measure of the one-loop quantum gravitational backreaction on inflation
Miao, S. P.; Tsamis, N. C.; Woodard, R. P.
2017-06-01
We use dimensional regularization in pure quantum gravity on a de Sitter background to evaluate the one-loop expectation value of an invariant operator which gives the local expansion rate. We show that the renormalization of this nonlocal composite operator can be accomplished using the counterterms of a simple local theory of gravity plus matter, at least at one-loop order. This renormalization completely absorbs the one-loop correction, which accords with the prediction that the lowest secular backreaction should be a two-loop effect.
Universality hypothesis breakdown at one-loop order
Carvalho, P. R. S.
2018-05-01
We probe the universality hypothesis by analytically computing the at least two-loop corrections to the critical exponents for q -deformed O (N ) self-interacting λ ϕ4 scalar field theories through six distinct and independent field-theoretic renormalization group methods and ɛ -expansion techniques. We show that the effect of q deformation on the one-loop corrections to the q -deformed critical exponents is null, so the universality hypothesis is broken down at this loop order. Such an effect emerges only at the two-loop and higher levels, and the validity of the universality hypothesis is restored. The q -deformed critical exponents obtained through the six methods are the same and, furthermore, reduce to their nondeformed values in the appropriated limit.
One-loop adjoint masses for non-supersymmetric intersecting branes
Energy Technology Data Exchange (ETDEWEB)
Anastasopoulos, P. [Technische Univ., Vienna (Austria). 1. Inst. fuer Theoretische Physik; Antoniadis, I. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Benakli, K. [CNRS, UPMC Univ. Paris (France). Lab. de Physique Theorique et Haute Energies; Goodsell, M.D. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Vichi, A. [Institute de Theorie des Phenomenes Physiques, EPFL, Lausanne (Switzerland)
2011-05-15
We consider breaking of supersymmetry in intersecting D-brane configurations by slight deviation of the angles from their supersymmetric values. We compute the masses generated by radiative corrections for the adjoint scalars on the brane world-volumes. In the open string channel, the string two-point function receives contributions only from the infrared and the ultraviolet limits. The latter is due to tree-level closed string uncanceled NS-NS tadpoles, which we explicitly reproduce from the effective Born-Infeld action. On the other hand, the infrared region reproduces the one-loop mediation of supersymmetry breaking in the effective gauge theory, via messengers and their Kaluza-Klein excitations. In the toroidal set-up considered here, it receives contributions only from N {approx} 4 and N {approx} 2 supersymmetric configurations, and thus always leads at leading order to a tachyonic direction, in agreement with effective field theory expectations. (orig.)
Supergraph analysis of the one-loop divergences in 6D, N=(1,0 and N=(1,1 gauge theories
Directory of Open Access Journals (Sweden)
I.L. Buchbinder
2017-08-01
Full Text Available We study the one-loop effective action for 6D, N=(1,0 supersymmetric Yang–Mills (SYM theory with hypermultiplets and 6D, N=(1,1 SYM theory as a subclass of the former, using the off-shell formulation of these theories in 6D, N=(1,0 harmonic superspace. We develop the corresponding supergraph technique and apply it to compute the one-loop divergences in the background field method ensuring the manifest gauge invariance. We calculate the two-point Green functions of the gauge superfield and the hypermultiplet, as well as the three-point gauge-hypermultipet Green function. Using these Green functions and exploiting gauge invariance of the theory, we find the full set of the off-shell one-loop divergent contributions, including the logarithmic and power ones. Our results precisely match with those obtained earlier in [1,2] within the proper time superfield method.
Results from GRACE/SUSY at one-loop
International Nuclear Information System (INIS)
Fujimoto, J.; Ishikawa, T.; Kurihara, Y.; Jimbo, M.; Yasui, Y.; Kaneko, T.; Kon, T.; Kuroda, M.; Shimizu, Y.
2007-01-01
We report the recent development on the SUSY calculations with the help of GRACE system. GRACE/SUSY/1LOOP is the computer code which can generate Feynman diagrams in the MSSM automatically and compute one-loop amplitudes in the numerical way. We present new results of various two-body widths and chargino pair production at ILC (international linear collider) at one-loop level. (author)
Physical interpretation of Schwinger's formula for effective actions
International Nuclear Information System (INIS)
Albuquerque, L.C. de; Farina, C.; Rabello, Silvio J.; Vaidya, Arvind N.
1994-01-01
We show explicitly that Schwinger's formula for one-loop effective actions corresponds to the summation of energies associated with the zero-point oscillations of the fields. We begin with a formal proof, and after that we confirm it using a regularization prescription. (author)
Effective action in multidimensional quantum gravity and spontaneous compactification
International Nuclear Information System (INIS)
Bagrov, V.G.; Bukhbinder, I.L.; Odintsov, S.D.
1987-01-01
One-loop effective action (the Casimir energy) is obtained for a special model of multidimensional quantum gravity and several variants of the d-dimensional quantum R 2 gravity in the space M 4 xT d-4 , where M 4 is the Minkowski space and T d-4 is the (d-4)-dimensional torus. It is shown that the effective action for the conformal gravity and the R 2 gravity without cosmological and Einstein's terms lead to an instability of the classical compactification. A numerical calculation reveals that the effective action for the five-dimensional R 2 gravity with the cosmological term is compatible with a self-consistent spontaneous compactification. The one-loop effective action is also obtained for the five dimensional Einstein gravity with the antisymmetrical torsion in the space M 4 xS 1 , where S 1 is the one-dimensional sphere
Effective action in multidimensional quantum gravity, and spontaneous compactification
International Nuclear Information System (INIS)
Bagrov, V.G.; Bukhbinder, I.L.; Odintsov, S.D.
1987-01-01
The one-loop effective action (Casimir energy) is obtained for a special form of model of multidimensional quantum gravity and for several variants of d-dimensional quantum R 2 -gravity on the space M 4 x T/sub d//sub -4/, where M 4 is Minkowski space and T/sub d//sub -4/ is the (d-4)-dimensional torus. It is shown that the effective action of the model of multidimensional quantum gravity and R 2 -gravity without the cosmological term and Einstein term leads to instability of the classical compactification. By a numerical calculation it is demonstrated that the effective action of five-dimensional R 2 -gravity with the cosmological term admits a self-consistent spontaneous compactification. The one-loop effective action is also found for five-dimensional Einstein gravity with antisymmetric torsion on the space M 4 x S 1 (S 1 is the one-dimensional sphere)
Algebraic evaluation of rational polynomials in one-loop amplitudes
International Nuclear Information System (INIS)
Binoth, Thomas; Guillet, Jean-Philippe; Heinrich, Gudrun
2007-01-01
One-loop amplitudes are to a large extent determined by their unitarity cuts in four dimensions. We show that the remaining rational terms can be obtained from the ultraviolet behaviour of the amplitude, and determine universal form factors for these rational parts by applying reduction techniques to the Feynman diagrammatic representation of the amplitude. The method is valid for massless and massive internal particles. We illustrate this method by evaluating the rational terms of the one-loop amplitudes for gg→H, γγ→γγ, gg→gg,γγ→ggg and γγ→γγγγ
Automated one-loop calculations with GoSam
International Nuclear Information System (INIS)
Cullen, G.; Greiner, N.; Heinrich, G.; Reiter, T.; Luisoni, G.; Mastrolia, P.; Padua Univ.; Ossola, G.; Tramontano, F.
2012-01-01
In this talk, the program package GOSAM is presented which can be used for the automated calculation of one-loop amplitudes for multi-particle processes. The integrands are generated in terms of Feynman diagrams and can be reduced by d-dimensional integrand-level decomposition, or tensor reduction, or a combination of both. Through various examples we show that GOSAM can produce one-loop amplitudes for both QCD and electroweak theory; model files for theories Beyond the Standard Model can be linked as well. (orig.)
One-loop infinities in dimensionally reduced supergravities
International Nuclear Information System (INIS)
Fradkin, E.S.; Tseytlin, A.A.
1983-11-01
It is proved explicitly in the paper that d=4 theory following via reduction from N=1, d=10 supergravities is not finite at one loop while the version of N=8 supergravity directly following from N=1, d=11 theory is one-loop finite. The method used is based on quantization of initial higher dimensional theory as a first step. The results also suggest possible existence of non-standard (higher N) d>4 supergravities which reduce to d=4 theories with finite N=8 supergravity sector. (author)
One-loop corrections to classical masses of kink families
International Nuclear Information System (INIS)
Alonso Izquierdo, A.; Garcia Fuertes, W.; Gonzalez Leon, M.A.; Mateos Guilarte, J.
2004-01-01
One-loop corrections to kink masses in a family of (1+1)-dimensional field theoretical models with two real scalar fields are computed. A generalized DHN formula applicable to potentials with and without reflection is obtained. It is shown how half-bound states arising in the spectrum of the second-order fluctuation operator for one-component topological kinks and the vacuum play a central role in the computation of the kink Casimir energy. The issue of whether or not the kink degeneracy exhibited by this family of models at the classical level survives one-loop quantum fluctuations is addressed
Automated one-loop calculations with GoSam
Energy Technology Data Exchange (ETDEWEB)
Cullen, G. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Greiner, N.; Heinrich, G.; Reiter, T. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Luisoni, G. [Durham Univ. (United Kingdom). Inst. for Particle Physics Phenomenology; Mastrolia, P. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Padua Univ. (Italy). Dipt. di Fisica; Ossola, G. [City Univ. of New York, NY (United States). New York City College of Technology; Tramontano, F. [CERN, Geneva (Switzerland). AS Div.
2012-01-15
In this talk, the program package GOSAM is presented which can be used for the automated calculation of one-loop amplitudes for multi-particle processes. The integrands are generated in terms of Feynman diagrams and can be reduced by d-dimensional integrand-level decomposition, or tensor reduction, or a combination of both. Through various examples we show that GOSAM can produce one-loop amplitudes for both QCD and electroweak theory; model files for theories Beyond the Standard Model can be linked as well. (orig.)
One-loop soft theorems via dual superconformal symmetry
Energy Technology Data Exchange (ETDEWEB)
Brandhuber, Andreas; Hughes, Edward; Spence, Bill; Travaglini, Gabriele [Centre for Research in String Theory, School of Physics and Astronomy,Queen Mary University of London,Mile End Road, London E1 4NS (United Kingdom)
2016-03-14
We study soft theorems at one loop in planar N = 4 super Yang-Mills theory through finite order in the infrared regulator and to subleading order in the soft parameter δ. In particular, we derive a universal constraint from dual superconformal symmetry, which we use to bootstrap subleading log δ behaviour. Moreover, we determine the complete infrared-finite subleading soft contribution of n-point MHV amplitudes using momentum twistors. Finally, we compute the subleading log δ behaviour of one-loop NMHV ratio functions at six and seven points, finding that universality holds within but not between helicity sectors.
Results from GRACE/SUSY at one-loop
Indian Academy of Sciences (India)
We report the recent development on the SUSY calculations with the help of GRACE system. GRACE/SUSY/1LOOP is the computer code which can generate Feynman diagrams in the MSSM automatically and compute one-loop amplitudes in the numerical way. We present new results of various two-body decay widths ...
A one-loop test of string duality
International Nuclear Information System (INIS)
Vafa, C.
1995-01-01
We test Type IIA-heterotic string duality in six dimensions by showing that the sigma model anomaly of the heterotic string is generated by a combination of a tree level and a string one-loop correction on the Type IIA side. (orig.)
One-loop contributions to neutral minima in the inert doublet model
Energy Technology Data Exchange (ETDEWEB)
Ferreira, P.M. [Instituto Superior de Engenharia de Lisboa - ISEL,1959-007 Lisboa (Portugal); Centro de Física Teórica e Computacional - FCUL,Universidade de Lisboa, R. Ernesto de Vasconcelos, 1749-016 Lisboa (Portugal); Świeżewska, Bogumiła [Faculty of Physics, University of Warsaw,Pasteura 5, 02-093 Warsaw (Poland)
2016-04-15
The vacuum structure of the inert doublet model is analysed at the one-loop level using the effective potential formalism, to verify the validity of tree-level predictions for the properties of the global minimum. An inert minimum (with massive fermions) and an inert-like minimum (with massless fermions) can coexist at tree level. But the one-loop analysis reveals that the allowed parameter space for the coexistence of more than one minimum is larger than the tree-level expected one. It is also shown that for some choices of parameters, the global minimum found at the one-loop level may be inert (or inert-like), contrary to what the tree-level analysis indicates.
Deformations, moduli stabilisation and gauge couplings at one-loop
Energy Technology Data Exchange (ETDEWEB)
Honecker, Gabriele; Koltermann, Isabel [PRISMA Cluster of Excellence, MITP & Institut für Physik (WA THEP),Johannes Gutenberg-Universität,Staudingerweg 9, 55128 Mainz (Germany); Staessens, Wieland [Instituto de Física Teórica UAM-CSIC, Universidad Autónoma de Madrid Cantoblanco,Calle de Nicolás Cabrera 13-15, 28049 Madrid (Spain); Departamento de Física Teórica, Universidad Autónoma de Madrid Cantoblanco,Calle de Nicolás Cabrera 13-15, 28049 Madrid (Spain)
2017-04-05
We investigate deformations of ℤ{sub 2} orbifold singularities on the toroidal orbifold T{sup 6}/(ℤ{sub 2}×ℤ{sub 6}) with discrete torsion in the framework of Type IIA orientifold model building with intersecting D6-branes wrapping special Lagrangian cycles. To this aim, we employ the hypersurface formalism developed previously for the orbifold T{sup 6}/(ℤ{sub 2}×ℤ{sub 2}) with discrete torsion and adapt it to the (ℤ{sub 2}×ℤ{sub 6}×ΩR) point group by modding out the remaining ℤ{sub 3} subsymmetry and the orientifold projection ΩR. We first study the local behaviour of the ℤ{sub 3}×ΩR invariant deformation orbits under non-zero deformation and then develop methods to assess the deformation effects on the fractional three-cycle volumes globally. We confirm that D6-branes supporting USp(2N) or SO(2N) gauge groups do not constrain any deformation, while deformation parameters associated to cycles wrapped by D6-branes with U(N) gauge groups are constrained by D-term supersymmetry breaking. These features are exposed in global prototype MSSM, Left-Right symmetric and Pati-Salam models first constructed in (DOI: 10.1016/j.nuclphysb.2015.10.009; 10.1002/prop.201400066), for which we here count the number of stabilised moduli and study flat directions changing the values of some gauge couplings. Finally, we confront the behaviour of tree-level gauge couplings under non-vanishing deformations along flat directions with the one-loop gauge threshold corrections at the orbifold point and discuss phenomenological implications, in particular on possible LARGE volume scenarios and the corresponding value of the string scale M{sub string}, for the same global D6-brane models.
Analytic results for the one loop NMHV H anti qqgg amplitude
Energy Technology Data Exchange (ETDEWEB)
Badger, Simon [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Campbell, John M. [Glasgow Univ. (United Kingdom). Dept. of Physics and Astronomy; Ellis, R. Keith [Fermilab, Batavia, IL (United States); Williams, Ciaran [Durham Univ. (United Kingdom). Dept. of Physics
2009-10-23
We compute the one-loop amplitude for a Higgs boson, a quark-antiquark pair and a pair of gluons of negative helicity, i.e. for the next-to-maximally helicity violating (NMHV) case, A(H, 1{sup -} {sub anti} {sub q}, 2{sup +}{sub q}, 3{sup -}{sub g}, 4{sup -}{sub g}). The calculation is performed using an effective Lagrangian which is valid in the limit of very large top quark mass. As a result of this paper all amplitudes for the transition of a Higgs boson into 4 partons are now known analytically at one-loop order. (orig.)
Analytic results for the one loop NMHV H anti qqgg amplitude
International Nuclear Information System (INIS)
Badger, Simon; Campbell, John M.; Williams, Ciaran
2009-01-01
We compute the one-loop amplitude for a Higgs boson, a quark-antiquark pair and a pair of gluons of negative helicity, i.e. for the next-to-maximally helicity violating (NMHV) case, A(H, 1 - anti q , 2 + q , 3 - g , 4 - g ). The calculation is performed using an effective Lagrangian which is valid in the limit of very large top quark mass. As a result of this paper all amplitudes for the transition of a Higgs boson into 4 partons are now known analytically at one-loop order. (orig.)
The soft-gluon current at one-loop order
Catani, S
2000-01-01
We study the soft limit of one-loop QCD amplitudes and we derive the process-independent factorization formula that controls the singular behaviour in this limit. This is obtained from the customary eikonal factorization formula valid at tree (classical) level by introducing a generalized soft-gluon current that embodies the quantum corrections. We compute the explicit expression of the soft-gluon current at one-loop order. It contains purely non-abelian correlations between the colour charges of each pair of hard-momentum partons in the matrix element. This leads to colour correlations between (two and) three hard partons in the matrix element squared. Exploiting colour conservation, we recover QED-like factorization for the square of the matrix elements with two and three hard partons.
One-loop calculations in QED in axial gauge
International Nuclear Information System (INIS)
Boos, E.E.; Kurannoy, S.S.
1983-01-01
The present paper pursued the aim to test at the simple example of the calculation of the anomalous magnetic moment in quantum electrodynamics the methods of calculating one-loop integrals in the axial gauge, using the dimensional regularization, and to investigate the independence of the results on the choice of the recipe of how to treat the poles in the denominators (k eta) -1 . It is shown that the techniques developed in another paper, as well as in the present paper, can be successfully applied in such calculations, in spite of the peculiarities of the axial gauge that have been discussed previously. The results of the two different ways of treating singularities (k eta) -1 (the principal value and 't Hooft's prescription) turn out to be equal. At the same time it was verified that the Green functions obtained by these calculations near the mass shell in the one-loop approximation satisfy the ward identity
One-Loop BPS amplitudes as BPS-state sums
Angelantonj, Carlo; Pioline, Boris
2012-01-01
Recently, we introduced a new procedure for computing a class of one-loop BPS-saturated amplitudes in String Theory, which expresses them as a sum of one-loop contributions of all perturbative BPS states in a manifestly T-duality invariant fashion. In this paper, we extend this procedure to all BPS-saturated amplitudes of the form \\int_F \\Gamma_{d+k,d} {\\Phi}, with {\\Phi} being a weak (almost) holomorphic modular form of weight -k/2. We use the fact that any such {\\Phi} can be expressed as a linear combination of certain absolutely convergent Poincar\\'e series, against which the fundamental domain F can be unfolded. The resulting BPS-state sum neatly exhibits the singularities of the amplitude at points of gauge symmetry enhancement, in a chamber-independent fashion. We illustrate our method with concrete examples of interest in heterotic string compactifications.
Automated one-loop calculations with GoSam
International Nuclear Information System (INIS)
Cullen, Gavin; Greiner, Nicolas; Heinrich, Gudrun; Reiter, Thomas; Luisoni, Gionata; Mastrolia, Pierpaolo; Ossola, Giovanni; Tramontano, Francesco
2012-01-01
We present the program package GoSam which is designed for the automated calculation of one-loop amplitudes for multi-particle processes in renormalisable quantum field theories. The amplitudes, which are generated in terms of Feynman diagrams, can be reduced using either D-dimensional integrand-level decomposition or tensor reduction. GoSam can be used to calculate one-loop QCD and/or electroweak corrections to Standard Model processes and offers the flexibility to link model files for theories Beyond the Standard Model. A standard interface to programs calculating real radiation is also implemented. We demonstrate the flexibility of the program by presenting examples of processes with up to six external legs attached to the loop. (orig.)
Automated One-Loop Calculations with GoSam
Cullen, Gavin; Heinrich, Gudrun; Luisoni, Gionata; Mastrolia, Pierpaolo; Ossola, Giovanni; Reiter, Thomas; Tramontano, Francesco
2012-01-01
We present the program package GoSam which is designed for the automated calculation of one-loop amplitudes for multi-particle processes in renormalisable quantum field theories. The amplitudes, which are generated in terms of Feynman diagrams, can be reduced using either D-dimensional integrand-level decomposition or tensor reduction. GoSam can be used to calculate one-loop QCD and/or electroweak corrections to Standard Model processes and offers the flexibility to link model files for theories Beyond the Standard Model. A standard interface to programs calculating real radiation is also implemented. We demonstrate the flexibility of the program by presenting examples of processes with up to six external legs attached to the loop.
One loop integration with hypergeometric series by using recursion relations
International Nuclear Information System (INIS)
Watanabe, Norihisa; Kaneko, Toshiaki
2014-01-01
General one-loop integrals with arbitrary mass and kinematical parameters in d-dimensional space-time are studied. By using Bernstein theorem, a recursion relation is obtained which connects (n + 1)-point to n-point functions. In solving this recursion relation, we have shown that one-loop integrals are expressed by a newly defined hypergeometric function, which is a special case of Aomoto-Gelfand hypergeometric functions. We have also obtained coefficients of power series expansion around 4-dimensional space-time for two-, three- and four-point functions. The numerical results are compared with ''LoopTools'' for the case of two- and three-point functions as examples
An ambiguity in one-loop quantum gravity
International Nuclear Information System (INIS)
Capper, D.M.; Kimber, D.P.
1980-01-01
It is argued that the application of the dimensional regularisation technique to one-loop quantum gravity calculations is ambiguous. However, for the calculation of on-mass-shell S-matrix elements, this ambiguity can be resolved by requiring consistency with results obtained from other regularisation schemes. Some discussion is also given of the implications of this work for recent attempts to use higher derivative Lagrangians to solve the renormalisability problem in quantum gravity. (author)
One-loop triple collinear splitting amplitudes in QCD
Energy Technology Data Exchange (ETDEWEB)
Badger, Simon; Buciuni, Francesco; Peraro, Tiziano [Higgs Centre for Theoretical Physics, School of Physics and Astronomy, University of Edinburgh,Edinburgh EH9 3JZ, Scotland (United Kingdom)
2015-09-28
We study the factorisation properties of one-loop scattering amplitudes in the triple collinear limit and extract the universal splitting amplitudes for processes initiated by a gluon. The splitting amplitudes are derived from the analytic Higgs plus four partons amplitudes. We present compact results for primitive helicity splitting amplitudes making use of super-symmetric decompositions. The universality of the collinear factorisation is checked numerically against the full colour six parton squared matrix elements.
Automated evaluation of one-loop scattering amplitudes
International Nuclear Information System (INIS)
Deurzen, Hans van
2015-01-01
In this dissertation the developments toward fully automated evaluation of one-loop scattering amplitudes will be presented, as implemented in the GoSam framework. The code Xsamurai, part of GoSam, is described, which implements the integrand reduction algorithm including an extension to higher-rank capability. GoSam was used to compute several Higgs boson production channels at NLO QCD. An interface between GoSam and a Monte Carlo program was constructed, which enables computing any process at NLO precision needed in the LHC era.
One-loop regularization of the Polyakov string functional
International Nuclear Information System (INIS)
Cohen, E.; Kluberg-Stern, H.; Peschanski, R.
1989-01-01
The divergences of the vacuum amplitude for the bosonic Polyakov string are studied at the one-loop level in a modular invariant regularization scheme, characterized by a dimensional cutoff analogous to proper time. As a result, the singular behaviour in the cutoff is not uniform in the range of the modulus variable and this yields a control on the singularities induced by the tachyon and the dilaton. The divergences are those of a sigma model, but the coefficients of the sigma-model counter-terms are different for the sphere and the flat torus. (orig.)
One-loop tensor Feynman integral reduction with signed minors
DEFF Research Database (Denmark)
Fleischer, Jochem; Riemann, Tord; Yundin, Valery
2012-01-01
of the formalism is the immediate evaluation of complete contractions of the tensor integrals with external momenta. This leads to the problem of evaluating sums over products of signed minors with scalar products of chords. Chords are differences of external momenta. These sums may be evaluated analytically......We present an algebraic approach to one-loop tensor integral reduction. The integrals are presented in terms of scalar one- to four-point functions. The reduction is worked out explicitly until five-point functions of rank five. The numerical C++ package PJFry evaluates tensor coefficients in terms...
Ambitwistor strings and the scattering equations at one loop
Energy Technology Data Exchange (ETDEWEB)
Adamo, Tim; Casali, Eduardo; Skinner, David [Department of Applied Mathematics & Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)
2014-04-15
Ambitwistor strings are chiral, infinite tension analogues of conventional string theory whose target space is the space of complex null geodesics and whose spectrum consists exclusively of massless states. At genus zero, these strings underpin the Cachazo-He-Yuan formulæ for tree level scattering of gravitons, gluons and scalars. In this paper we extend these formulæ in a number of directions. Firstly, we consider Ramond sector vertex operators and construct simple amplitudes involving space-time fermions. These agree with tree amplitudes in ten dimensional supergravity and super Yang-Mills. We then show that, after the usual GSO projections, the ambitwistor string partition function is modular invariant. We consider the scattering equations at genus one, and calculate one loop scattering amplitudes for NS-NS external states in the Type II ambitwistor string. We conjecture that these give new representations of (the integrand of) one loop supergravity amplitudes and we show that they have the expected behaviour under factorization of the worldsheet in both non-separating and separating degenerations.
One-loop renormalization of a gravity-scalar system
Energy Technology Data Exchange (ETDEWEB)
Park, I.Y. [Philander Smith College, Department of Applied Mathematics, Little Rock, AR (United States)
2017-05-15
Extending the renormalizability proposal of the physical sector of 4D Einstein gravity, we have recently proposed renormalizability of the 3D physical sector of gravity-matter systems. The main goal of the present work is to conduct systematic one-loop renormalization of a gravity-matter system by applying our foliation-based quantization scheme. In this work we explicitly carry out renormalization of a gravity-scalar system with a Higgs-type potential. With the fluctuation part of the scalar field gauged away, the system becomes renormalizable through a metric field redefinition. We use dimensional regularization throughout. One of the salient aspects of our analysis is how the graviton propagator acquires the ''mass'' term. One-loop calculations lead to renormalization of the cosmological and Newton constants. We discuss other implications of our results as well: time-varying vacuum energy density and masses of the elementary particles as well as the potential relevance of Neumann boundary condition for black hole information. (orig.)
Reduction schemes for one-loop tensor integrals
International Nuclear Information System (INIS)
Denner, A.; Dittmaier, S.
2006-01-01
We present new methods for the evaluation of one-loop tensor integrals which have been used in the calculation of the complete electroweak one-loop corrections to e + e - ->4 fermions. The described methods for 3-point and 4-point integrals are, in particular, applicable in the case where the conventional Passarino-Veltman reduction breaks down owing to the appearance of Gram determinants in the denominator. One method consists of different variants for expanding tensor coefficients about limits of vanishing Gram determinants or other kinematical determinants, thereby reducing all tensor coefficients to the usual scalar integrals. In a second method a specific tensor coefficient with a logarithmic integrand is evaluated numerically, and the remaining coefficients as well as the standard scalar integral are algebraically derived from this coefficient. For 5-point tensor integrals, we give explicit formulas that reduce the corresponding tensor coefficients to coefficients of 4-point integrals with tensor rank reduced by one. Similar formulas are provided for 6-point functions, and the generalization to functions with more internal propagators is straightforward. All the presented methods are also applicable if infrared (soft or collinear) divergences are treated in dimensional regularization or if mass parameters (for unstable particles) become complex
One-loop renormalization of a gravity-scalar system
International Nuclear Information System (INIS)
Park, I.Y.
2017-01-01
Extending the renormalizability proposal of the physical sector of 4D Einstein gravity, we have recently proposed renormalizability of the 3D physical sector of gravity-matter systems. The main goal of the present work is to conduct systematic one-loop renormalization of a gravity-matter system by applying our foliation-based quantization scheme. In this work we explicitly carry out renormalization of a gravity-scalar system with a Higgs-type potential. With the fluctuation part of the scalar field gauged away, the system becomes renormalizable through a metric field redefinition. We use dimensional regularization throughout. One of the salient aspects of our analysis is how the graviton propagator acquires the ''mass'' term. One-loop calculations lead to renormalization of the cosmological and Newton constants. We discuss other implications of our results as well: time-varying vacuum energy density and masses of the elementary particles as well as the potential relevance of Neumann boundary condition for black hole information. (orig.)
One-loop renormalization of a gravity-scalar system
Park, I. Y.
2017-05-01
Extending the renormalizability proposal of the physical sector of 4D Einstein gravity, we have recently proposed renormalizability of the 3D physical sector of gravity-matter systems. The main goal of the present work is to conduct systematic one-loop renormalization of a gravity-matter system by applying our foliation-based quantization scheme. In this work we explicitly carry out renormalization of a gravity-scalar system with a Higgs-type potential. With the fluctuation part of the scalar field gauged away, the system becomes renormalizable through a metric field redefinition. We use dimensional regularization throughout. One of the salient aspects of our analysis is how the graviton propagator acquires the "mass" term. One-loop calculations lead to renormalization of the cosmological and Newton constants. We discuss other implications of our results as well: time-varying vacuum energy density and masses of the elementary particles as well as the potential relevance of Neumann boundary condition for black hole information.
The effective action in Einstein-Maxwell theory
Bastianelli, Fiorenzo; Davila, Jose Manuel; Schubert, Christian
2008-01-01
Considerable work has been done on the one-loop effective action in combined electromagnetic and gravitational fields, particularly as a tool for determining the properties of light propagation in curved space. After a short review of previous work, I present some recent results obtained using the worldline formalism. In particular, I will discuss various ways of generalizing the QED Euler-Heisenberg Lagrangian to the Einstein-Maxwell case.
One-loop quantum gravity repulsion in the early Universe.
Broda, Bogusław
2011-03-11
Perturbative quantum gravity formalism is applied to compute the lowest order corrections to the classical spatially flat cosmological Friedmann-Lemaître-Robertson-Walker solution (for the radiation). The presented approach is analogous to the approach applied to compute quantum corrections to the Coulomb potential in electrodynamics, or rather to the approach applied to compute quantum corrections to the Schwarzschild solution in gravity. In the framework of the standard perturbative quantum gravity, it is shown that the corrections to the classical deceleration, coming from the one-loop graviton vacuum polarization (self-energy), have (UV cutoff free) opposite to the classical repulsive properties which are not negligible in the very early Universe. The repulsive "quantum forces" resemble those known from loop quantum cosmology.
One-loop tensor integrals in dimensional regularisation
International Nuclear Information System (INIS)
Campbell, J.M.; Glover, E.W.N.; Miller, D.J.
1997-01-01
We show how to evaluate tensor one-loop integrals in momentum space avoiding the usual plague of Gram determinants. We do this by constructing combinations of n- and (n-1)-point scalar integrals that are finite in the limit of vanishing Gram determinant. These non-trivial combinations of dilogarithms, logarithms and constants are systematically obtained by either differentiating with respect to the external parameters - essentially yielding scalar integrals with Feynman parameters in the numerator - or by developing the scalar integral in D=6-2ε or higher dimensions. An additional advantage is that other spurious kinematic singularities are also controlled. As an explicit example, we develop the tensor integrals and associated scalar integral combinations for processes where the internal particles are massless and where up to five (four massless and one massive) external particles are involved. For more general processes, we present the equations needed for deriving the relevant combinations of scalar integrals. (orig.)
One-loop renormalization of Lee-Wick gauge theory
International Nuclear Information System (INIS)
Grinstein, Benjamin; O'Connell, Donal
2008-01-01
We examine the renormalization of Lee-Wick gauge theory to one-loop order. We show that only knowledge of the wave function renormalization is necessary to determine the running couplings, anomalous dimensions, and vector boson masses. In particular, the logarithmic running of the Lee-Wick vector boson mass is exactly related to the running of the coupling. In the case of an asymptotically free theory, the vector boson mass runs to infinity in the ultraviolet. Thus, the UV fixed point of the pure gauge theory is an ordinary quantum field theory. We find that the coupling runs more quickly in Lee-Wick gauge theory than in ordinary gauge theory, so the Lee-Wick standard model does not naturally unify at any scale. Finally, we present results on the beta function of more general theories containing dimension six operators which differ from previous results in the literature.
A differential operator for integrating one-loop scattering equations
Energy Technology Data Exchange (ETDEWEB)
Wang, Tianheng [Department of Physics, Nanjing University,Nanjing, Jiangsu Province (China); Chen, Gang [Department of Physics, Zhejiang Normal University,Jinhua, Zhejiang Province (China); Department of Physics and Astronomy, Uppsala University,Uppsala (Sweden); Department of Physics, Nanjing University,Nanjing, Jiangsu Province (China); Cheung, Yeuk-Kwan E. [Department of Physics, Nanjing University,Nanjing, Jiangsu Province (China); Xu, Feng [Weavi Corporation Limited, Nanjing,Jiangsu Province (China)
2017-01-09
We propose a differential operator for computing the residues associated with a class of meromorphic n-forms that frequently appear in the Cachazo-He-Yuan form of the scattering amplitudes. This differential operator is conjectured to be uniquely determined by the local duality theorem and the intersection number of the divisors in the n-form. We use the operator to evaluate the one-loop integrand of Yang-Mills theory from their generalized CHY formulae. The method can reduce the complexity of the calculation. In addition, the expression for the 1-loop four-point Yang-Mills integrand obtained in our approach has a clear correspondence with the Q-cut results.
On the low-energy limit of one-loop photon-graviton amplitudes
International Nuclear Information System (INIS)
Bastianelli, F.; Corradini, O.; Dávila, J.M.; Schubert, C.
2012-01-01
We present first results of a systematic study of the structure of the low-energy limit of the one-loop photon-graviton amplitudes induced by massive scalars and spinors. Our main objective is the search of KLT-type relations where effectively two photons merge into a graviton. We find such a relation at the graviton-photon-photon level. We also derive the diffeomorphism Ward identity for the 1PI one-graviton-N-photon amplitudes.
One-loop correlation functions in the model of noncritical fermionic strings
International Nuclear Information System (INIS)
Belokurov, V.V.; Iofa, M.Z.
1996-01-01
In the model of noncritical fermionic strings, the David-Distler-Kawai ansatz is used to study one-loop n-point (n≤4) correlation functions for the vertex operators of massless bosonic states. The action functional of the model is the sum of super-Liouville action functional for the conformal mode and the action functional of d scalar supermultiplets. It is assumed that the total cosmological term is equal to zero. The amplitudes are calculated as the residues at the pole of the correlation function that corresponds to the conservation of Liouville momentum in the form Σβi=Q(1-h), where Q=√(9-d)/2 and h is the genus of the work sheet. In the one-loop approximation, the amplitudes can be obtained in the modular-invariant form, provided that the coefficients appearing in the sum over spin structures depend on moduli. In this case, the modular measure is defined up to a modular-invariant factor. This arbitrariness can be used to represent one-point correlation functions in the same functional form as for strings of critical dimension
The effective action in (2+1)-dimensional gravity and generalized BF topological field theory
Energy Technology Data Exchange (ETDEWEB)
Birmingham, D. (Theory Div., CERN, Geneva (Switzerland)); Gibbs, R.; Mokhtari, S. (Physics Dept., Louisiana Tech Univ., Ruston, LA (United States))
1991-07-11
The one-loop off-shell effective action is studied for the case of generalized BF theories in three dimensions, including, for example, (2 + 1)-dimensional gravity with a cosmological constant. The phase contribution to the effective action, originating from the {eta}-function of a particular first order operator, is calculated using a momentum space technique. It is found that the {eta}-function is proportional to the classical action. (orig.).
The effective action in (2+1)-dimensional gravity and generalized BF topological field theory
International Nuclear Information System (INIS)
Birmingham, D.; Gibbs, R.; Mokhtari, S.
1991-01-01
The one-loop off-shell effective action is studied for the case of generalized BF theories in three dimensions, including, for example, (2 + 1)-dimensional gravity with a cosmological constant. The phase contribution to the effective action, originating from the η-function of a particular first order operator, is calculated using a momentum space technique. It is found that the η-function is proportional to the classical action. (orig.)
International Nuclear Information System (INIS)
Goto, T.; Tsushima, H.; Sakurai, N.; Jo, T.
2006-01-01
MONJU is a prototype fast breeder reactor (FBR). Modification work commenced in March 2005. Since June 2004, MONJU has changed to one-loop operation of the primary heat transport system (PHTS) with all of the secondary heat transport systems (SHTS) drained of sodium. The purposes of this change are to shorten the modification period and to reduce the cost incurred for circuit trace heating electrical consumption. Before changing condition, the following issues were investigated to show that this mode of operation was possible. The heat loss from the reactor vessel and the single primary loop must exceed the decay heat by an acceptable margin but the capacity of pre-heaters to keep the sodium within the primary vessel at about 200 deg. C must be maintained. With regard to the heat loss and the decay heat, the estimated heat loss in the primary system was in the range of 90-170 kW in one-loop operation, and the calculated decay heat was 21.2 kW. Although the heat input of the primary pump was considered, it was clear that circuit heat loss greatly exceeded the decay heat. As for pre-heaters, effective capacity was less than the heat loss. Therefore, the temperature of the reactor vessel room was raised to reduce the heat loss. One-loop operation of the PHTS was able to be executed by means of these measures. The cost of electrical consumption in the power plant has been reduced by one-loop operation of the PHTS and the modification period was shortened. (authors)
One-loop masses of open-string scalar fields in string theory
International Nuclear Information System (INIS)
Kitazawa, Noriaki
2008-01-01
In phenomenological models with D-branes, there are in general open-string massless scalar fields, in addition to closed-string massless moduli fields corresponding to the compactification. It is interesting to focus on the fate of such scalar fields in models with broken supersymmetry, because no symmetry forbids their masses. The one-loop effect may give non-zero masses to them, and in some cases mass squared may become negative, which means the radiative gauge symmetry breaking. In this article we investigate and propose a simple method for calculating the one-loop corrections using the boundary state formalism. There are two categories of massless open-string scalar fields. One consists the gauge potential fields corresponding to compactified directions, which can be understood as scalar fields in uncompactified space-time (related with Wilson line degrees of freedom). The other consists 'gauge potential fields' corresponding to transverse directions of D-brane, which emerge as scalar fields in D-brane world-volume (related with brane moduli fields). The D-brane boundary states with constant backgrounds of these scalar fields are constructed, and one-loop scalar masses are calculated in the closed string picture. Explicit calculations are given in the following four concrete models: one D25-brane with a circle compactification in bosonic string theory, one D9-brane with a circle compactification in superstring theory, D3-branes at a supersymmetric C 3 /Z 3 orbifold singularity, and a model of brane supersymmetry breaking with D3-branes and anti-D7-branes at a supersymmetric C 3 /Z 3 orbifold singularity. We show that the sign of the mass squared has a strong correlation with the sign of the related open-string one-loop vacuum amplitude.
One-loop tensor Feynman integral reduction with signed minors
International Nuclear Information System (INIS)
Fleischer, J.; Yundin, V.
2011-12-01
We present an algebraic approach to one-loop tensor integral reduction. The integrals are presented in terms of scalar one- to four-point functions. The reduction is worked out explicitly until five-point functions of rank five. The numerical C++ package PJFry evaluates tensor coefficients in terms of a basis of scalar integrals, which is provided by an external library, e.g. QCDLoop. We shortly describe installation and use of PJFry. Examples for numerical results are shown, including a special treatment for small or vanishing inverse four-point Gram determinants. An extremely efficient application of the formalism is the immediate evaluation of complete contractions of the tensor integrals with external momenta. This leads to the problem of evaluating sums over products of signed minors with scalar products of chords. Chords are differences of external momenta. These sums may be evaluated analytically in a systematic way. The final expressions for the numerical evaluation are then compact combinations of the contributing basic scalar functions. (orig.)
One-loop tensor Feynman integral reduction with signed minors
Energy Technology Data Exchange (ETDEWEB)
Fleischer, J. [Bielefeld Univ. (Germany). Fakultaet fuer Physik; Riemann, T. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Yundin, V. [Copenhagen Univ. (Denmark). Niels Bohr International Academy and Discovery Center
2011-12-15
We present an algebraic approach to one-loop tensor integral reduction. The integrals are presented in terms of scalar one- to four-point functions. The reduction is worked out explicitly until five-point functions of rank five. The numerical C++ package PJFry evaluates tensor coefficients in terms of a basis of scalar integrals, which is provided by an external library, e.g. QCDLoop. We shortly describe installation and use of PJFry. Examples for numerical results are shown, including a special treatment for small or vanishing inverse four-point Gram determinants. An extremely efficient application of the formalism is the immediate evaluation of complete contractions of the tensor integrals with external momenta. This leads to the problem of evaluating sums over products of signed minors with scalar products of chords. Chords are differences of external momenta. These sums may be evaluated analytically in a systematic way. The final expressions for the numerical evaluation are then compact combinations of the contributing basic scalar functions. (orig.)
Gluons and gravitons at one loop from ambitwistor strings
Geyer, Yvonne; Monteiro, Ricardo
2018-03-01
We present new and explicit formulae for the one-loop integrands of scattering amplitudes in non-supersymmetric gauge theory and gravity, valid for any number of particles. The results exhibit the colour-kinematics duality in gauge theory and the double-copy relation to gravity, in a form that was recently observed in supersymmetric theories. The new formulae are expressed in a particular representation of the loop integrand, with only one quadratic propagator, which arises naturally from the framework of the loop-level scattering equations. The starting point in our work are the expressions based on the scattering equations that were recently derived from ambitwistor string theory. We turn these expressions into explicit formulae depending only on the loop momentum, the external momenta and the external polarisations. These formulae are valid in any number of spacetime dimensions for pure Yang-Mills theory (gluon) and its natural double copy, NS-NS gravity (graviton, dilaton, B-field), and we also present formulae in four spacetime dimensions for pure gravity (graviton). We perform several tests of our results, such as checking gauge invariance and directly matching our four-particle formulae to previously known expressions. While these tests would be elaborate in a Feynman-type representation of the loop integrand, they become straightforward in the representation we use.
Grzywacz, Piotr; Qin, Jian; Morse, David C
2007-12-01
Attempts to use coarse-grained molecular theories to calculate corrections to the random-phase approximation (RPA) for correlations in polymer mixtures have been plagued by an unwanted sensitivity to the value of an arbitrary cutoff length, i.e., by an ultraviolet (UV) divergence. We analyze the UV divergence of the inverse structure factor S(-1)(k) predicted by a "one-loop" approximation similar to that used in several previous studies. We consider both miscible homopolymer blends and disordered diblock copolymer melts. We show, in both cases, that all UV divergent contributions can be absorbed into a renormalization of the values of the phenomenological parameters of a generalized self-consistent field theory (SCFT). This observation allows the construction of an UV convergent theory of corrections to SCFT phenomenology. The UV-divergent one-loop contribution to S(-1)(k) is shown to be the sum of (i) a k -independent contribution that arises from a renormalization of the effective chi parameter, (ii) a k-dependent contribution that arises from a renormalization of monomer statistical segment lengths, (iii) a contribution proportional to k(2) that arises from a square-gradient contribution to the one-loop fluctuation free energy, and (iv) a k-dependent contribution that is inversely proportional to the degree of polymerization, which arises from local perturbations in fluid structure near chain ends and near junctions between blocks in block copolymers.
Comparing EFT and Exact One-Loop Analyses of Non-Degenerate Stops
Drozd, Aleksandra; Quevillon, Jeremie; You, Tevong
2015-01-01
We develop a universal approach to the one-loop effective field theory (EFT) using the Covariant Derivative Expansion (CDE) method. We generalise previous results to include broader classes of UV models, showing how expressions previously obtained assuming degenerate heavy-particle masses can be extended to non-degenerate cases. We apply our method to the general MSSM with non-degenerate stop squarks, illustrating our approach with calculations of the coefficients of dimension-6 operators contributing to the $hgg$ and $h\\gamma\\gamma$ couplings, and comparing with exact calculations of one-loop Feynman diagrams. We then use present and projected future sensitivities to these operator coefficients to obtain present and possible future indirect constraints on stop masses. The current sensitivity is already comparable to that of direct LHC searches, and future FCC-ee measurements could be sensitive to stop masses above a TeV. The universality of our one-loop EFT approach facilitates extending these constraints to...
Complete algebraic reduction of one-loop tensor Feynman integrals
International Nuclear Information System (INIS)
Fleischer, J.; Riemann, T.
2011-01-01
We set up a new, flexible approach for the tensor reduction of one-loop Feynman integrals. The 5-point tensor integrals up to rank R=5 are expressed by 4-point tensor integrals of rank R-1, such that the appearance of the inverse 5-point Gram determinant is avoided. The 4-point tensor coefficients are represented in terms of 4-point integrals, defined in d dimensions, 4-2ε≤d≤4-2ε+2(R-1), with higher powers of the propagators. They can be further reduced to expressions which stay free of the inverse 4-point Gram determinants but contain higher-dimensional 4-point integrals with only the first power of scalar propagators, plus 3-point tensor coefficients. A direct evaluation of the higher-dimensional 4-point functions would avoid the appearance of inverse powers of the Gram determinants completely. The simplest approach, however, is to apply here dimensional recurrence relations in order to reduce them to the familiar 2- to 4-point functions in generic dimension d=4-2ε, introducing thereby coefficients with inverse 4-point Gram determinants up to power R for tensors of rank R. For small or vanishing Gram determinants--where this reduction is not applicable--we use analytic expansions in positive powers of the Gram determinants. Improving the convergence of the expansions substantially with Pade approximants we close up to the evaluation of the 4-point tensor coefficients for larger Gram determinants. Finally, some relations are discussed which may be useful for analytic simplifications of Feynman diagrams.
The generalized Schwinger-DeWitt technique and the unique effective action in quantum gravity
International Nuclear Information System (INIS)
Barvinsky, A.O.; Vilkovisky, G.A.
1983-01-01
We consider the one-loop approximation to the recently proposed unique effective action in gauge theory. The Schwinger-DeWitt technique is generalized and applied to the computation of the unique gravitational counterterms. The issue of asymptotic freedom is reexamined. (orig.)
International Nuclear Information System (INIS)
DeWitt, B.
1987-01-01
The concept of the effective action in quantum field theory was introduced into physics by Julian Schwinger in 1954. The effective action summarizes, in a single functional, all the quantum properties of the fields under consideration. The functional derivative of the effective action yields the effective field equations, which replace the classical field equations as descriptors of the dynamical behavior of quantized fields. Solutions of these equations are 'in-out' matrix elements of the field operators and, when substituted back into the effective action itself, yield logarithms of the corresponding 'in-out' amplitudes. The classical field equations are gauge covariant, a fact that derives from the gauge invariance of the classical action. One has learned how to construct effective actions that are similarly gauge invariant (in each order of perturbation theory) and that yield effective field equations having the covariance properties of their classical analogs. Despite this advance, problems remain, stemming from the fact that there is not one but an infinite number of gauge invariant effective actions, one for every background-covariant choice of supplementary conditions and ghost fields. Vilkovisky (1984) has argued persuasively that by requiring additionally that the effective action be invariant under local invertible changes in the choice of basic field variables, one can construct a natural unique gauge invariant effective action. This lecture will examine Vilkovisky's ideas. 3 refs
Energy Technology Data Exchange (ETDEWEB)
Ahn, C.
1989-08-01
We study two aspects of one loop structures in quantum field theories which describe two different areas of particle physics: the one loop unitarity behavior of the Standard Model of electroweak interactions and modular invariance of string model theory. Loop expansion has its importance in that it contains quantum fluctuations due to all physical states in the theory. Therefore, by studying the various models to one loop, we can understand how the contents of the theory can contribute to physically measurable quantities and how the consistency at quantum level restricts the physical states of the theory, as well. In the first half of the thesis, we study one loop corrections to the process {ital e}{sup +}{ital e}{sup {minus}} {yields} {ital W}{sup +}{ital W}{sup {minus}}. In this process, there is a delicate unitarity-saving cancellation between s-channel and t-channel tree level Feynman diagrams. If the one loop contribution due to heavy particles corrects the channels asymmetrically, the cancellation, hence unitarity, will be delayed up to the mass scale of these heavy particles. We refer to this phenomena as the unitarity delay effect. Due to this effect, cross section below these mass scales can have significant radiative corrections which may provide an appropriate window through which we can see the high energy structure of the Standard Model from relatively low energy experiments. In the second half, we will show how quantum consistency can restrict the physical states in string theory. 53 refs., 13 figs.
Dark matter stability and one-loop neutrino mass generation based on Peccei-Quinn symmetry
Energy Technology Data Exchange (ETDEWEB)
Suematsu, Daijiro [Kanazawa University, Institute for Theoretical Physics, Kanazawa (Japan)
2018-01-15
We propose a model which is a simple extension of the KSVZ invisible axion model with an inert doublet scalar. Peccei-Quinn symmetry forbids tree-level neutrino mass generation and its remnant Z{sub 2} symmetry guarantees dark matter stability. The neutrino masses are generated by one-loop effects as a result of the breaking of Peccei-Quinn symmetry through a nonrenormalizable interaction. Although the low energy effective model coincides with an original scotogenic model which contains right-handed neutrinos with large masses, it is free from the strong CP problem. (orig.)
Dark matter stability and one-loop neutrino mass generation based on Peccei-Quinn symmetry
Suematsu, Daijiro
2018-01-01
We propose a model which is a simple extension of the KSVZ invisible axion model with an inert doublet scalar. Peccei-Quinn symmetry forbids tree-level neutrino mass generation and its remnant Z_2 symmetry guarantees dark matter stability. The neutrino masses are generated by one-loop effects as a result of the breaking of Peccei-Quinn symmetry through a nonrenormalizable interaction. Although the low energy effective model coincides with an original scotogenic model which contains right-handed neutrinos with large masses, it is free from the strong CP problem.
One-loop stabilization of the fuzzy four-sphere via softly broken SUSY
Energy Technology Data Exchange (ETDEWEB)
Steinacker, Harold C. [Faculty of Physics, University of Vienna,Boltzmanngasse 5, A-1090 Vienna (Austria)
2015-12-17
We describe a stabilization mechanism for fuzzy S{sub N}{sup 4} in the Euclidean IIB matrix model due to vacuum energy in the presence of a positive mass term. The one-loop effective potential for the radius contains an attractive contribution attributed to supergravity, while the mass term induces a repulsive contribution for small radius due to SUSY breaking. This leads to a stabilization of the radius. The mechanism should be pertinent to recent results on the genesis of 3+1-dimensional space-time in the Minkowskian IIB model.
Grimbach, A; Knechtli, F; Palombi, Filippo
2008-01-01
We calculate analytically the improvement coefficients of the static axial and vector currents in O(a) improved lattice QCD at one-loop order of perturbation theory. The static quark is described by the hypercubic action, previously introduced in the literature in order to improve the signal-to-noise ratio of static observables. Within a Schroedinger Functional setup, we derive the Feynman rules of the hypercubic link in time-momentum representation. The improvement coefficients are obtained from on-shell correlators of the static axial and vector currents. As a by-product, we localise the minimum of the static self-energy as a function of the smearing parameters of the action at one-loop order and show that the perturbative minimum is close to its non-perturbative counterpart.
One-loop divergences in the quantum theory of supergravity
International Nuclear Information System (INIS)
Nieuwenhuizen, P. van; Vermaseren, J.A.M.
1976-01-01
Supergravity does not lead to a finite quantum theory of gravitation when coupled to the spin 1, 1/2 matter multiplet. The S-matrix of photon-photon scattering diverges; its divergences are proportional to the square of the photon energy-momentum tensor, in agreement with electro-magnetic duality and chiral invariance. The graviton self-energy corrections are divergent in pure supergravity as well as in the coupled Maxwell-Einstein system and satisfy their Ward identity because the supersymmetry ghost field is commuting. The photon-graviton vertex corrections diverge, as expected from the non-invariance of the action under local scale transformations, and satisfy the equivalence principle at the quantum level. The photon self-energy is divergent. (Auth.)
Effective action, massive gravitons and the Cosmological Constant
Energy Technology Data Exchange (ETDEWEB)
Garattini, Remo [Universita degli Studi di Bergamo, Facolta di Ingegneria, Viale Marconi 5, 24044 Dalmine (Bergamo) (Italy); INFN - sezione di Milano, Via Celoria 16, Milan (Italy)
2006-03-01
The one loop effective action in a Schwarzschild background is here used to compute the cosmological constant in presence of massive gravitons. It is shown that the expression of the Zero Point Energy (ZPE) is equivalent to the one computed by means of a variational approach. To handle with ZPE divergences, we use the zeta function regularization. The regularization is closely related to the subtraction procedure appearing in the computation of Casimir energy in a curved background. A renormalization procedure is introduced to remove the infinities together with a renormalization group equation.
Effective action, massive gravitons and the Cosmological Constant
International Nuclear Information System (INIS)
Garattini, Remo
2006-01-01
The one loop effective action in a Schwarzschild background is here used to compute the cosmological constant in presence of massive gravitons. It is shown that the expression of the Zero Point Energy (ZPE) is equivalent to the one computed by means of a variational approach. To handle with ZPE divergences, we use the zeta function regularization. The regularization is closely related to the subtraction procedure appearing in the computation of Casimir energy in a curved background. A renormalization procedure is introduced to remove the infinities together with a renormalization group equation
Unimodular gravity and the lepton anomalous magnetic moment at one-loop
Energy Technology Data Exchange (ETDEWEB)
Martín, Carmelo P., E-mail: carmelop@fis.ucm.es [Departamento de Física Teórica I, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040 Madrid (Spain)
2017-07-01
We work out the one-loop contribution to the lepton anomalous magnetic moment coming from Unimodular Gravity. We use Dimensional Regularization and Dimensional Reduction to carry out the computations. In either case, we find that Unimodular Gravity gives rise to the same one-loop correction as that of General Relativity.
Complete one-loop renormalization of the Higgs-electroweak chiral Lagrangian
Buchalla, G.; Catà, O.; Celis, A.; Knecht, M.; Krause, C.
2018-03-01
Employing background-field method and super-heat-kernel expansion, we compute the complete one-loop renormalization of the electroweak chiral Lagrangian with a light Higgs boson. Earlier results from purely scalar fluctuations are confirmed as a special case. We also recover the one-loop renormalization of the conventional Standard Model in the appropriate limit.
One-loop renormalization of Resonance Chiral Theory: scalar and pseudoscalar resonances
International Nuclear Information System (INIS)
Rosell, Ignasi; Ruiz-FemenIa, Pedro; Portoles, Jorge
2005-01-01
We consider the Resonance Chiral Theory with one multiplet of scalar and pseudoscalar resonances, up to bilinear couplings in the resonance fields, and evaluate its β-function at one-loop with the use of the background field method. Thus we also provide the full set of operators that renormalize the theory at one loop and render it finite
Reducing full one-loop amplitudes to scalar integrals at the integrand level
International Nuclear Information System (INIS)
Ossola, Giovanni; Papadopoulos, Costas G.; Pittau, Roberto
2007-01-01
We show how to extract the coefficients of the 4-, 3-, 2- and 1-point one-loop scalar integrals from the full one-loop amplitude of arbitrary scattering processes. In a similar fashion, also the rational terms can be derived. Basically no information on the analytical structure of the amplitude is required, making our method appealing for an efficient numerical implementation
Reducing full one-loop amplitudes to scalar integrals at the integrand level
Ossola, Giovanni; Papadopoulos, Costas G.; Pittau, Roberto
2007-02-01
We show how to extract the coefficients of the 4-, 3-, 2- and 1-point one-loop scalar integrals from the full one-loop amplitude of arbitrary scattering processes. In a similar fashion, also the rational terms can be derived. Basically no information on the analytical structure of the amplitude is required, making our method appealing for an efficient numerical implementation.
A one-loop study of matching conditions for static-light flavor currents
Energy Technology Data Exchange (ETDEWEB)
Hesse, Dirk [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Parma Univ. (Italy); Sommer, Rainer [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Collaboration: ALPHA Collaboration
2012-11-15
Heavy Quark Effective Theory (HQET) computations of semi-leptonic decays, e.g. B{yields}{pi}l{nu}, require the knowledge of the parameters in the effective theory for all components of the heavy-light flavor currents. So far non-perturbative matching conditions have been employed only for the time component of the axial current. Here we perform a check of matching conditions for the time component of the vector current and the spatial component of the axial vector current up to one-loop order of perturbation theory and to lowest order of the 1/m-expansion. We find that the proposed observables have small higher order terms in the 1/m-series and are thus excellent candidates for a non-perturbative matching procedure.
One-loop divergences in chiral perturbation theory and right-invariant metrics on SU(3)
International Nuclear Information System (INIS)
Esposito-Farese, G.
1991-01-01
In the framework of chiral perturbation theory, we compute the one-loop divergences of the effective Lagrangian describing strong and non-leptonic weak interactions of pseudoscalar mesons. We use the background field method and the heat-kernel expansion, and underline the geometrical meaning of the different terms, showing how the right-invariance of the metrics on SU(3) allows to clarify and simplify the calculations. Our results are given in terms of a minimal set of independent counterterms, and shorten previous ones of the literature, in the particular case where the electromagnetic field is the only external source which is considered. We also show that a geometrical construction of the effective Lagrangian at order O(p 4 ) allows to derive some relations between the finite parts of the coupling constants. These relations do not depend on the scale μ used to renormalize. (orig.)
On Resumming Inflationary Perturbations beyond One-loop
DEFF Research Database (Denmark)
Riotto, Antonio; Sloth, Martin Snoager
2008-01-01
It is well known that the correlation functions of a scalar field in a quasi-de Sitter space exhibit at the loop level cumulative infra-red effects proportional to the total number of e-foldings of inflation. Using the in-in formalism, we explore the behavior of these infra-red effects in the large...... N limit of an O(N) invariant scalar field theory with quartic self-interactions. By resumming all higher-order loop diagrams non-perturbatively, we show that the connected four-point correlation function, which is a signal of non-Gaussianity, is non-perturbatively enhanced with respect to its tree-level...
Phenomenological aspects of heterotic orbifold models at one loop
International Nuclear Information System (INIS)
Birkedal-Hansen, A.; Binetruy, P.; Mambrini, Y.; Nelson, B.
2003-01-01
We provide a detailed study of the phenomenology of orbifold compactifications of the heterotic string within the context of supergravity effective theories. Our investigation focuses on those models where the soft Lagrangian is dominated by loop contributions to the various soft supersymmetry breaking parameters. Such models typically predict non-universal soft masses and are thus significantly different from minimal supergravity and other universal models. We consider the pattern of masses that are governed by these soft terms and investigate the implications of certain indirect constraints on supersymmetric models, such as flavor-changing neutral currents, the anomalous magnetic moment of the muon and the density of thermal relic neutralinos. These string-motivated models show novel behavior that interpolates between the phenomenology of unified supergravity models and models dominated by the superconformal anomaly
Low-mass Higgs decays to four leptons at one loop and beyond
Energy Technology Data Exchange (ETDEWEB)
Kniehl, Bernd A.; Veretin, Oleg L. [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik
2012-06-15
The ongoing searches for Higgs-boson signals in data taken at the CERN LHC and the Fermilab Tevatron crucially rely on the decay channels H{yields}Zll and H{yields}Wl{nu}{sub l}. We present a precision study of the partial widths of these decay channels including the full one-loop electroweak corrections and the dominant contributions at two and three loops, of O(G{sub F}{sup 2}m{sub t}{sup 4}), O(G{sub F}m{sub t}{sup 2}{alpha}{sub s}), and O(G{sub F}m{sub t}{sup 2}{alpha}{sub s}{sup 2}). Since the invariant mass of the off-shell intermediate boson is relatively low in the mass window 115 GeV< m{sub H}<129 GeV of current interest, lepton mass effects are relevant, especially for the {tau} lepton. (orig.)
Computing the effective action with the functional renormalization group
Energy Technology Data Exchange (ETDEWEB)
Codello, Alessandro [CP3-Origins and the Danish IAS University of Southern Denmark, Odense (Denmark); Percacci, Roberto [SISSA, Trieste (Italy); INFN, Sezione di Trieste, Trieste (Italy); Rachwal, Leslaw [Fudan University, Department of Physics, Center for Field Theory and Particle Physics, Shanghai (China); Tonero, Alberto [ICTP-SAIFR and IFT, Sao Paulo (Brazil)
2016-04-15
The ''exact'' or ''functional'' renormalization group equation describes the renormalization group flow of the effective average action Γ{sub k}. The ordinary effective action Γ{sub 0} can be obtained by integrating the flow equation from an ultraviolet scale k = Λ down to k = 0. We give several examples of such calculations at one-loop, both in renormalizable and in effective field theories. We reproduce the four-point scattering amplitude in the case of a real scalar field theory with quartic potential and in the case of the pion chiral Lagrangian. In the case of gauge theories, we reproduce the vacuum polarization of QED and of Yang-Mills theory. We also compute the two-point functions for scalars and gravitons in the effective field theory of scalar fields minimally coupled to gravity. (orig.)
Precise predictions of higgs boson decays including the full one-loop corrections in supersymmetry
International Nuclear Information System (INIS)
Frisch, W.
2011-01-01
The Standard Model of elementary particle physics is a highly successful theory, describing the electromagnetic, strong and weak interaction of matter particles up to energy scales to a few hundred giga electronvolt. Despite its great success in explaining experimental results correctly, there is hardly no doubt that the SM is an effective theory, which means that the theory loses its predictability at higher energies. Therefore, the Standard Model has to be extended in a proper way to describe physics at higher energies. A most promising concept for the extension of the SM is those of Supersymmetry, where for each particle of the SM one or more superpartner particles are introduced. The simplest and most attractive extension of the SM is called Minimal Supersymmetric Standard Model (MSSM). Minimal refers to the additional field content, which is kept as low as possible. In fact the MSSM consists of the fields of the SM and their corresponding supersymmetric partner fields, as well as one additional Higgs doublet. The presence of this additional Higgs doublet leads to the existence of five physical Higgs bosons in the MSSM. The search for supersymmetric particles and Higgs bosons is one of the primary goals of the Large Hadron Collider (LHC) at the CERN laboratory, producing collisions at sufficiently high energies to detect these particles. For the discovery of these new particles, precise pre- dictions of the corresponding decay widths and branching rations are utmost mandatory. To contribute with the precision of the LHC and the future ILC, Feynman amplitudes should be calculated at least to one-loop order. Since these calculations lead to so called UV- and IR- divergences, it is essential to perform a renormalization procedure, where the divergences are subtracted by a proper definition of counterterms. The goal of this work was to develop a program package, which calculates all MSSM two- body Higgs decay widths and corresponding branching ratios at full one-loop
arXiv Diagrammatic Hopf algebra of cut Feynman integrals: the one-loop case
Abreu, Samuel; Duhr, Claude; Gardi, Einan
2017-12-15
We construct a diagrammatic coaction acting on one-loop Feynman graphs and their cuts. The graphs are naturally identified with the corresponding (cut) Feynman integrals in dimensional regularization, whose coefficients of the Laurent expansion in the dimensional regulator are multiple polylogarithms (MPLs). Our main result is the conjecture that this diagrammatic coaction reproduces the combinatorics of the coaction on MPLs order by order in the Laurent expansion. We show that our conjecture holds in a broad range of nontrivial one-loop integrals. We then explore its consequences for the study of discontinuities of Feynman integrals, and the differential equations that they satisfy. In particular, using the diagrammatic coaction along with information from cuts, we explicitly derive differential equations for any one-loop Feynman integral. We also explain how to construct the symbol of any one-loop Feynman integral recursively. Finally, we show that our diagrammatic coaction follows, in the special case of o...
Analytic determination at one loop of the energy-momentum tensor for lattice QCD
International Nuclear Information System (INIS)
Caracciolo, S.; Menotti, P.; Pelissetto, A.
1991-01-01
We give a completely analytical determinaton of the corrections to the naive energy-momentum tensor for lattice QCD at one loop. This tenor is conserved and gives rise to the correct trace anomaly. (orig.)
Explicit evaluation of covariant one-loop four-point amplitude for open fermionic string
International Nuclear Information System (INIS)
Yamamoto, Hisashi; Nakazawa, Naohito.
1986-11-01
We carry out the explicit evaluation of the covariant one-loop amplitude with four massless external bosons for open fermionic string by the operator formalism. The resulting expression of the amplitude completely coincides with that of the light-cone new formalism for type-I superstring theory, providing the explicit demonstration for the one-loop equivalence of the old and new formalisms for the open superstring theory at the four-point interacting level. (author)
The one-loop Green's functions of dimensionally reduced gauge theories
International Nuclear Information System (INIS)
Ketov, S.V.; Prager, Y.S.
1988-01-01
The dimensional regularization technique as well as that by dimensional reduction is applied to the calculation of the regularized one-loop Green's functions in dsub(o)-dimensional Yang-Mills theory with real massless scalars and spinors in arbitrary (real) representations of a gauge group G. As a particular example, the super-symmetrically regularized one-loop Green's functions of the N=4 supersymmetric Yang-Mills model are derived. (author). 17 refs
The Z decay width in the SMEFT: y{sub t} and λ corrections at one loop
Energy Technology Data Exchange (ETDEWEB)
Hartmann, Christine [Niels Bohr International Academy, University of Copenhagen,Blegdamsvej 17, DK-2100 Copenhagen (Denmark); Shepherd, William [Niels Bohr International Academy, University of Copenhagen,Blegdamsvej 17, DK-2100 Copenhagen (Denmark); Institut für Physik, Johannes-Gutenberg-Universität Mainz,Staudingerweg 7, D-55128 Mainz (Germany); Trott, Michael [Niels Bohr International Academy, University of Copenhagen,Blegdamsvej 17, DK-2100 Copenhagen (Denmark)
2017-03-10
We calculate one loop y{sub t} and λ dependent corrections to Γ̄{sub Z},R̄{sub f}{sup 0} and the partial Z widths due to dimension six operators in the Standard Model Effective Field Theory (SMEFT), including finite terms. We assume CP symmetry and a U(3){sup 5} symmetry in the UV matching onto the dimension six operators, dominantly broken by the Standard Model Yukawa matrices. Corrections to these observables are predicted using the input parameters {α̂_e_w,M̂_Z,Ĝ_F,m̂_t,m̂_h} extracted with one loop corrections in the same limit. We show that at one loop the number of SMEFT parameters contributing to the precise LEPI pseudo-observables exceeds the number of measurements. As a result the SMEFT parameters contributing to LEP data are formally unbounded when the size of loop corrections are reached until other data is considered in a global analysis. The size of these loop effects is generically a correction of order ∼% to leading effects in the SMEFT, but we find multiple large numerical coefficients in our calculation at this order. We use a (MS)-bar scheme, modified for the SMEFT, for renormalization. Some subtleties involving novel evanescent scheme dependence present in this result are explained.
International Nuclear Information System (INIS)
Davies, Scott
2011-01-01
We combine the six-dimensional helicity formalism of Cheung and O'Connell with D-dimensional generalized unitarity to obtain a new formalism for computing one-loop amplitudes in dimensionally regularized QCD. With this procedure, we simultaneously obtain the pieces that are constructible from four-dimensional unitarity cuts and the rational pieces that are missed by them, while retaining a helicity formalism. We illustrate the procedure using four- and five-point one-loop amplitudes in QCD, including examples with external fermions. We also demonstrate the technique's effectiveness in next-to-leading order QCD corrections to Higgs processes by computing the next-to-leading order correction to the Higgs plus three positive-helicity gluons amplitude in the large top-quark mass limit.
One-loop analysis of the electroweak breaking in supersymmetric models and the fine-tuning problem
De Carlos, B
1993-01-01
We examine the electroweak breaking mechanism in the minimal supersymmetric standard model (MSSM) using the {\\em complete} one-loop effective potential $V_1$. First, we study what is the region of the whole MSSM parameter space (i.e. $M_{1/2},m_o,\\mu,...$) that leads to a succesful $SU(2)\\times U(1)$ breaking with an acceptable top quark mass. In doing this it is observed that all the one-loop corrections to $V_1$ (even the apparently small ones) must be taken into account in order to get reliable results. We find that the allowed region of parameters is considerably enhanced with respect to former "improved" tree level results. Next, we study the fine-tuning problem associated with the high sensitivity of $M_Z$ to $h_t$ (the top Yukawa coupling). Again, we find that this fine-tuning is appreciably smaller once the one-loop effects are considered than in previous tree level calculations. Finally, we explore the ambiguities and limitations of the ordinary criterion to estimate the degree of fine-tuning. As a r...
Effective action and brane running
International Nuclear Information System (INIS)
Brevik, Iver; Ghoroku, Kazuo; Yahiro, Masanobu
2004-01-01
We address the renormalized effective action for a Randall-Sundrum brane running in 5D bulk space. The running behavior of the brane action is obtained by shifting the brane position without changing the background and fluctuations. After an appropriate renormalization, we obtain an effective, low energy brane world action, in which the effective 4D Planck mass is independent of the running position. We address some implications for this effective action
Effective action and the quantum equation of motion
International Nuclear Information System (INIS)
Branchina, V.; Faivre, H.; Zappala, D.
2004-01-01
We carefully analyze the use of the effective action in dynamical problems, in particular the conditions under which the equation (δΓ)/(δφ) = 0 can be used as a quantum equation of motion and illustrate in detail the crucial relation between the asymptotic states involved in the definition of Γ and the initial state of the system. Also, by considering the quantum-mechanical example of a double-well potential, where we can get exact results for the time evolution of the system, we show that an approximation to the effective potential in the quantum equation of motion that correctly describes the dynamical evolution of the system is obtained with the help of the wilsonian RG equation (already at the lowest order of the derivative expansion), while the commonly used one-loop effective potential fails to reproduce the exact results. (orig.)
One-loop calculations in quantum field theory: From Feynman diagrams to unitarity cuts
International Nuclear Information System (INIS)
Ellis, R. Keith; Kunszt, Zoltan; Melnikov, Kirill; Zanderighi, Giulia
2012-01-01
The success of the experimental program at the Tevatron re-inforced the idea that precision physics at hadron colliders is desirable and, indeed, possible. The Tevatron data strongly suggests that one-loop computations in QCD describe hard scattering well. Extrapolating this observation to the LHC, we conclude that knowledge of many short-distance processes at next-to-leading order may be required to describe the physics of hard scattering. While the field of one-loop computations is quite mature, parton multiplicities in hard LHC events are so high that traditional computational techniques become inefficient. Recently, new approaches based on unitarity have been developed for calculating one-loop scattering amplitudes in quantum field theory. These methods are especially suitable for the description of multi-particle processes in QCD and are amenable to numerical implementations. We present a systematic pedagogical description of both conceptual and technical aspects of the new methods.
One-loop calculations in quantum field theory: from Feynman diagrams to unitarity cuts
Energy Technology Data Exchange (ETDEWEB)
Ellis, R. Keith [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Kunszt, Zoltan [Institute for Theoretical Physics (Switzerland); Melnikov, Kirill [Johns Hopkins Univ., Baltimore, MD (United States); Zanderighi, Giulia [Rudolf Peierls Centre for Theoretical Physics (United Kingdom)
2012-09-01
The success of the experimental program at the Tevatron re-inforced the idea that precision physics at hadron colliders is desirable and, indeed, possible. The Tevatron data strongly suggests that one-loop computations in QCD describe hard scattering well. Extrapolating this observation to the LHC, we conclude that knowledge of many short-distance processes at next-to-leading order may be required to describe the physics of hard scattering. While the field of one-loop computations is quite mature, parton multiplicities in hard LHC events are so high that traditional computational techniques become inefficient. Recently new approaches based on unitarity have been developed for calculating one-loop scattering amplitudes in quantum field theory. These methods are especially suitable for the description of multi-particle processes in QCD and are amenable to numerical implementations. We present a systematic pedagogical description of both conceptual and technical aspects of the new methods.
From high-scale leptogenesis to low-scale one-loop neutrino mass generation
Zhou, Hang; Gu, Pei-Hong
2018-02-01
We show that a high-scale leptogenesis can be consistent with a low-scale one-loop neutrino mass generation. Our models are based on the SU(3)c × SU(2)L × U(1)Y × U(1) B - L gauge groups. Except a complex singlet scalar for the U(1) B - L symmetry breaking, the other new scalars and fermions (one scalar doublet, two or more real scalar singlets/triplets and three right-handed neutrinos) are odd under an unbroken Z2 discrete symmetry. The real scalar decays can produce an asymmetry stored in the new scalar doublet which subsequently decays into the standard model lepton doublets and the right-handed neutrinos. The lepton asymmetry in the standard model leptons then can be partially converted to a baryon asymmetry by the sphaleron processes. By integrating out the heavy scalar singlets/triplets, we can realize an effective theory to radiatively generate the small neutrino masses at the TeV scale. Furthermore, the lightest right-handed neutrino can serve as a dark matter candidate.
Effective action of softly broken supersymmetric theories
International Nuclear Information System (INIS)
Groot Nibbelink, S.; Nyawelo, T.S
2006-12-01
We study the renormalization of (softly) broken supersymmetric theories at the one loop level in detail. We perform this analysis in a superspace approach in which the supersymmetry breaking interactions are parameterized using spurion insertions. We comment on the uniqueness of this parameterization. We compute the one loop renormalization of such theories by calculating superspace vacuum graphs with multiple spurion insertions. To preform this computation efficiently we develop algebraic properties of spurion operators, that naturally arise because the spurions are often surrounded by superspace projection operators. Our results are general apart from the restrictions that higher super covariant derivative terms and some finite effects due to non-commutativity of superfield dependent mass matrices are ignored. One of the soft potentials induces renormalization of the Kaehler potential. (author)
Scalar one-loop vertex integrals as meromorphic functions of space-time dimension d
International Nuclear Information System (INIS)
Bluemlein, Johannes; Phan, Khiem Hong; Vietnam National Univ., Ho Chi Minh City; Riemann, Tord; Silesia Univ., Chorzow
2017-11-01
Representations are derived for the basic scalar one-loop vertex Feynman integrals as meromorphic functions of the space-time dimension d in terms of (generalized) hypergeometric functions 2 F 1 and F 1 . Values at asymptotic or exceptional kinematic points as well as expansions around the singular points at d=4+2n, n non-negative integers, may be derived from the representations easily. The Feynman integrals studied here may be used as building blocks for the calculation of one-loop and higher-loop scalar and tensor amplitudes. From the recursion relation presented, higher n-point functions may be obtained in a straightforward manner.
The rational parts of one-loop QCD amplitudes I: The general formalism
International Nuclear Information System (INIS)
Xiao Zhiguang; Yang Gang; Zhu Chuanjie
2006-01-01
A general formalism for computing only the rational parts of one-loop QCD amplitudes is developed. Starting from the Feynman integral representation of the one-loop amplitude, we use tensor reduction and recursive relations to compute the rational parts directly. Explicit formulas for the rational parts are given for all bubble and triangle integrals. Formulas are also given for box integrals up to two-mass-hard boxes which are the needed ingredients to compute up to 6-gluon QCD amplitudes. We use this method to compute explicitly the rational parts of the 5- and 6-gluon QCD amplitudes in two accompanying papers
GoSam: A program for automated one-loop calculations
International Nuclear Information System (INIS)
Cullen, G; Greiner, N; Heinrich, G; Mastrolia, P; Reiter, T; Luisoni, G; Ossola, G; Tramontano, F
2012-01-01
The program package GoSam is presented which aims at the automated calculation of one-loop amplitudes for multi-particle processes. The amplitudes are generated in terms of Feynman diagrams and can be reduced using either D-dimensional integrand-level decomposition or tensor reduction, or a combination of both. GoSam can be used to calculate one-loop corrections to both QCD and electroweak theory, and model files for theories Beyond the Standard Model can be linked as well. A standard interface to programs calculating real radiation is also included. The flexibility of the program is demonstrated by various examples.
GoSam. A program for automated one-loop calculations
International Nuclear Information System (INIS)
Cullen, G.; Greiner, N.; Heinrich, G.; Reiter, T.; Luisoni, G.
2011-11-01
The program package GoSam is presented which aims at the automated calculation of one-loop amplitudes for multi-particle processes. The amplitudes are generated in terms of Feynman diagrams and can be reduced using either D-dimensional integrand-level decomposition or tensor reduction, or a combination of both. GoSam can be used to calculate one-loop corrections to both QCD and electroweak theory, and model files for theories Beyond the Standard Model can be linked as well. A standard interface to programs calculating real radiation is also included. The flexibility of the program is demonstrated by various examples. (orig.)
GoSam. A program for automated one-loop calculations
Energy Technology Data Exchange (ETDEWEB)
Cullen, G. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Greiner, N.; Heinrich, G.; Reiter, T. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Luisoni, G. [Durham Univ. (United Kingdom). Inst. for Particle Physics Phenomenology; Mastrolia, P. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Padua Univ. (Italy). Dipt. di Fisica; Ossola, G. [City Univ. of New York, NY (United States). New York City College of Technology; Tramontano, F. [European Organization for Nuclear Research (CERN), Geneva (Switzerland)
2011-11-15
The program package GoSam is presented which aims at the automated calculation of one-loop amplitudes for multi-particle processes. The amplitudes are generated in terms of Feynman diagrams and can be reduced using either D-dimensional integrand-level decomposition or tensor reduction, or a combination of both. GoSam can be used to calculate one-loop corrections to both QCD and electroweak theory, and model files for theories Beyond the Standard Model can be linked as well. A standard interface to programs calculating real radiation is also included. The flexibility of the program is demonstrated by various examples. (orig.)
One-loop calculation in time-dependent non-equilibrium thermo field dynamics
International Nuclear Information System (INIS)
Umezawa, H.; Yamanaka, Y.
1989-01-01
This paper is a review on the structure of thermo field dynamics (TFD) in which the basic concepts such as the thermal doublets, the quasi-particles and the self-consistent renormalization are presented in detail. A strong emphasis is put on the computational scheme. A detailed structure of this scheme is illustrated by the one-loop calculation in a non-equilibrium time-dependent process. A detailed account of the one-loop calculation has never been reported anywhere. The role of the self-consistent renormalization is explained. The equilibrium TFD is obtained as the long-time limit of non-equilibrium TFD. (author)
One-particle reducible contribution to the one-loop spinor propagator in a constant field
Directory of Open Access Journals (Sweden)
N. Ahmadiniaz
2017-11-01
Full Text Available Extending work by Gies and Karbstein on the Euler–Heisenberg Lagrangian, it has recently been shown that the one-loop propagator of a charged scalar particle in a constant electromagnetic field has a one-particle reducible contribution in addition to the well-studied irreducible one. Here we further generalize this result to the spinor case, and find the same relation between the reducible term, the tree-level propagator and the one-loop Euler–Heisenberg Lagrangian as in the scalar case. Our demonstration uses a novel worldline path integral representation of the photon-dressed spinor propagator in a constant electromagnetic field background.
Exact effective actions for quarks in pure and self-dual mean fields
International Nuclear Information System (INIS)
Elizalde, E.; Soto, J.
1985-01-01
The QCD effective action for ordinary quarks in the presence of a constant self-dual, pure colormagnetic or pure color-electric background created by themselves is calculated at all loop orders. This is done in a very simple way, by using zeta-function regularization and the fact that the dependence of the effective action on the background can be factorized in these three cases, leaving a well-defined constant factor. The zero mode problem and the imaginary contributions are seen to be mere one-loop artifacts which automatically vanish when the exact calculation is carried out. (orig.)
Numerical evaluation of one-loop diagrams near exceptional momentum configurations
International Nuclear Information System (INIS)
Giele, Walter T.; Zanderighi, Giulia; Glover, E.W.N.
2004-01-01
One problem which plagues the numerical evaluation of one-loop Feynman diagrams using recursive integration by part relations is a numerical instability near exceptional momentum configurations. In this contribution we will discuss a generic solution to this problem. As an example we consider the case of forward light-by-light scattering
The one loop calculation of the strong coupling β function in the Toy Model
International Nuclear Information System (INIS)
Bai Zhiming; Jiang Yuanfang
1991-01-01
The background field quantization is used to calculate the one-loop β function in the Toy Model which has the strong coupling and the SU(3) symmetry. The function obtained is consistent with the Appalquist-Carrazone theorem in the low energy condition
A mapping between Feynman and string motivated one-loop rules in gauge theories
International Nuclear Information System (INIS)
Bern, Z.
1992-01-01
Recently, computationally efficient rules for one-loop gauge theory amplitudes have been derived from string theory. We demonstrate the relationship of the compact string organization of the amplitude to Feynman diagrams. In particular, we explicitly show how large cancellations inherent in conventional Feynman diagram computations are avoided by the string motivated rules. (orig.)
IR finite one-loop box scalar integral with massless internal lines
International Nuclear Information System (INIS)
Duplancic, G.; Nizic, B.
2002-01-01
The IR finite one-loop box scalar integral with massless internal lines has been recalculated. The result is very compact, simple and valid for arbitrary values of the relevant kinematic variables. It is given in terms of only two dilogarithms and a few logarithms, all of very simple arguments. (orig.)
Appell functions and the scalar one-loop three-point integrals in Feynman diagrams
Energy Technology Data Exchange (ETDEWEB)
Cabral-Rosetti, L G [Departamento de Posgrado, Centro Interdisciplinario de Investigacion y Docencia en Educacion Tecnica (CIIDET), Av. Universidad 282 Pte., Col. Centro, A. Postal 752, C.P. 76000, Santiago de Queretaro, Qro. (Mexico); Sanchis-Lozano, M A [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, 46100 Burjassot, Valencia (Spain)
2006-05-15
The scalar three-point function appearing in one-loop Feynman diagrams is compactly expressed in terms of a generalized hypergeometric function of two variables. Use is made of the connection between such Appell function and dilogarithms coming from a previous investigation. Special cases are obtained for particular values of internal masses and external momenta.
One-loop helicity amplitudes for t anti t production at hadron colliders
International Nuclear Information System (INIS)
Badger, Simon; Yundin, Valery
2011-01-01
We present compact analytic expressions for all one-loop helicity amplitudes contributing to t anti t production at hadron colliders. Using recently developed generalised unitarity methods and a traditional Feynman based approach we produce a fast and flexible implementation. (ORIG.)
One-loop helicity amplitudes for t anti t production at hadron colliders
Energy Technology Data Exchange (ETDEWEB)
Badger, Simon [The Niels Bohr International Academy and Discovery Center, Copenhagen (Denmark). Niels Bohr Inst.; Sattler, Ralf [Humboldt Univ. Berlin (Germany). Inst. fuer Physik; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Yundin, Valery [Silesia Univ., Katowice (Poland). Inst. of Physics; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2011-01-15
We present compact analytic expressions for all one-loop helicity amplitudes contributing to t anti t production at hadron colliders. Using recently developed generalised unitarity methods and a traditional Feynman based approach we produce a fast and flexible implementation. (ORIG.)
Bergman, Ramona; Andersson-Sköld, Yvonne; Nyberg, Lars; Johansson, Magnus
2010-05-01
In a project funded by the Swedish Civil Contingencies Agency, the effort and work to reduce different kinds of accidents are being evaluated. The project wants to illuminate the links between actions and outcome, so we can learn from today's performance and in the future select more effective measures and overall deal with accidents more efficiently. The project ESS covers the field of frequent accidents such as sliding accidents at home, in house fires and less common accidents such as chemical and land fill accidents up to even more rare accidents such as natural accidents and hazards. In the ESS project SGI (Swedish geotechnical institute) will evaluate the work and effort concerning various natural hazards limited to landslides, erosion and flooding. The aim is to investigate how municipalities handle, especially prevention, of such natural disasters today. The project includes several aspects such as: • which are the driving forces for risk analysis in a municipality • do one use risk mapping (and what type) in municipal risk analysis • which aspects are most important when selecting preventive measures • in which way do one learn from past accidents • and from previous accidents elsewhere, by for example use existing databases • etc There are many aspects that play a role in a well-functioning safety promotion work. The overall goal is to examine present work and activities, highlight what is well functioning and identify weak points. The aim is to find out where more resources are needed and give suggestions for a more efficient security work. This includes identification of the most efficient "tools" in use or needed. Such tools can be education, directives, funding, more easily available maps and information regarding previous accidents and preventive measures etc. The project will result in recommendations for more effective ways to deal with landslides, erosion and flooding. Since different kinds of problems can occur depending on level of
Third-Order Density Perturbation and One-Loop Power Spectrum in Dark-Energy-Dominated Universe
Takahashi, Ryuichi
2008-01-01
We investigate the third-order density perturbation and the one-loop correction to the linear power spectrum in the dark-energy cosmological model. Our main interest is to understand the dark-energy effect on baryon acoustic oscillations in a quasi-nonlinear regime ($k \\approx 0.1h$/Mpc). Analytical solutions and simple fitting formulae are presented for the dark-energy model with the general time-varying equation of state $w(a)$. It turns out that the power spectrum coincides with the approx...
One-loop QCD thermodynamics in a strong homogeneous and static magnetic field
Rath, Shubhalaxmi; Patra, Binoy Krishna
2017-12-01
We have studied how the equation of state of thermal QCD with two light flavors is modified in a strong magnetic field. We calculate the thermodynamic observables of hot QCD matter up to one-loop, where the magnetic field affects mainly the quark contribution and the gluon part is largely unaffected except for the softening of the screening mass. We have first calculated the pressure of a thermal QCD medium in a strong magnetic field, where the pressure at fixed temperature increases with the magnetic field faster than the increase with the temperature at constant magnetic field. This can be understood from the dominant scale of thermal medium in the strong magnetic field, being the magnetic field, in the same way that the temperature dominates in a thermal medium in the absence of magnetic field. Thus although the presence of a strong magnetic field makes the pressure of hot QCD medium larger, the dependence of pressure on the temperature becomes less steep. Consistent with the above observations, the entropy density is found to decrease with the temperature in the presence of a strong magnetic field which is again consistent with the fact that the strong magnetic field restricts the dynamics of quarks to two dimensions, hence the phase space becomes squeezed resulting in the reduction of number of microstates. Moreover the energy density is seen to decrease and the speed of sound of thermal QCD medium increases in the presence of a strong magnetic field. These findings could have phenomenological implications in heavy ion collisions because the expansion dynamics of the medium produced in non-central ultra-relativistic heavy ion collisions is effectively controlled by both the energy density and the speed of sound.
Complete one-loop electroweak corrections to ZZZ production at the ILC
International Nuclear Information System (INIS)
Su Jijuan; Ma Wengan; Zhang Renyou; Wang Shaoming; Guo Lei
2008-01-01
We study the complete O(α ew ) electroweak (EW) corrections to the production of three Z 0 bosons in the framework of the standard model (SM) at the ILC. The leading-order and the EW next-to-leading-order corrected cross sections are presented, and their dependence on the colliding energy √(s) and Higgs-boson mass m H is analyzed. We investigate also the LO and one-loop EW corrected distributions of the transverse momentum of the final Z 0 boson, and the invariant mass of the Z 0 Z 0 pair. Our numerical results show that the EW one-loop correction generally suppresses the tree-level cross section, and the relative correction with m H =120 GeV(150 GeV) varies between -15.8%(-13.9%) and -7.5%(-6.2%) when √(s) goes up from 350 GeV to 1 TeV.
New BCJ representations for one-loop amplitudes in gauge theories and gravity
He, Song; Schlotterer, Oliver; Zhang, Yong
2018-05-01
We explain a procedure to manifest the Bern-Carrasco-Johansson duality between color and kinematics in n-point one-loop amplitudes of a variety of supersymmetric gauge theories. Explicit amplitude representations are constructed through a systematic reorganization of the integrands in the Cachazo-He-Yuan formalism. Our construction holds for any nonzero number of supersymmetries and does not depend on the number of spacetime dimensions. The cancellations from supersymmetry multiplets in the loop as well as the resulting power counting of loop momenta is manifested along the lines of the corresponding superstring computations. The setup is used to derive the one-loop version of the Kawai-Lewellen-Tye formula for the loop integrands of gravitational amplitudes.
arXiv Cuts from residues: the one-loop case
Abreu, Samuel; Duhr, Claude; Gardi, Einan
2017-06-14
Using the multivariate residue calculus of Leray, we give a precise definition of the notion of a cut Feynman integral in dimensional regularization, as a residue evaluated on the variety where some of the propagators are put on shell. These are naturally associated to Landau singularities of the first type. Focusing on the one-loop case, we give an explicit parametrization to compute such cut integrals, with which we study some of their properties and list explicit results for maximal and next-to-maximal cuts. By analyzing homology groups, we show that cut integrals associated to Landau singularities of the second type are specific combinations of the usual cut integrals, and we obtain linear relations among different cuts of the same integral. We also show that all one-loop Feynman integrals and their cuts belong to the same class of functions, which can be written as parametric integrals.
Spoiling of radiation zeros at the one-loop level and infrared finiteness
International Nuclear Information System (INIS)
Laursen, M.L.; Samuel, M.A.; Sen, A.
1983-01-01
We consider the amplitude for the radiative decay W - →phi 1 phi 2 #betta# (scalar quarks) including one-loop gluon corrections. We study this process to see if the amplitude (radiation) zeros found in lowest order survive at the one-loop level. The subset of diagrams containing self-mass insertions preserves the zero. Seagull types are shown to have a violation which is similar to kappanot =1. Triangle and box diagrams spoil the zeros as they do in the case of a scalar W. However, the amplitude is completely free of any mass singularities in the classical null zone. We conjecture that this will remain true for spin-(1/2) quarks
Off-Shell Green Functions: One-Loop with Growing Legs
International Nuclear Information System (INIS)
Bashir, A.; Concha-Sanchez, Y.; Delbourgo, R.; Tejeda-Yeomans, M. E.
2008-01-01
One loop calculations in gauge theories in arbitrary gauge and dimensions become exceedingly hard with growing number of external off-shell legs. Let alone higher point functions, such a calculation for even the three point one-loop vertices for quantum electrodynamics (QED) and quantum chromodynamics (QCD) has been made available only recently. In this article, we discuss how Ward-Fradkin-Green-Takahashi identities (WFGTI) may provide a helpful tool in these computations. After providing a glimpse of our suggestion for the case of the 3-point vertex, we present our preliminary findings towards our similar efforts for the 4-point function. We restrict ourselves to the example of scalar quantum electrodynamics (SQED)
Non-Gaussianity at tree and one-loop levels from vector field perturbations
International Nuclear Information System (INIS)
Valenzuela-Toledo, Cesar A.; Rodriguez, Yeinzon; Lyth, David H.
2009-01-01
We study the spectrum P ζ and bispectrum B ζ of the primordial curvature perturbation ζ when the latter is generated by scalar and vector field perturbations. The tree-level and one-loop contributions from vector field perturbations are worked out considering the possibility that the one-loop contributions may be dominant over the tree-level terms [both (either) in P ζ and (or) in B ζ ] and vice versa. The level of non-Gaussianity in the bispectrum, f NL , is calculated and related to the level of statistical anisotropy in the power spectrum, g ζ . For very small amounts of statistical anisotropy in the power spectrum, the level of non-Gaussianity may be very high, in some cases exceeding the current observational limit.
On-shell recurrence relations for one-loop QCD amplitudes
International Nuclear Information System (INIS)
Bern, Zvi; Dixon, Lance J.; Kosower, David A.
2005-01-01
We present examples of on-shell recurrence relations for determining rational functions appearing in one-loop QCD amplitudes. In particular, we give relations for one-loop QCD amplitudes with all legs of positive helicity, or with one leg of negative helicity and the rest of positive helicity. Our recurrence relations are similar to the tree-level ones described by Britto, Cachazo, Feng, and Witten. A number of new features arise for loop amplitudes in nonsupersymmetric theories like QCD, including boundary terms and double poles. We show how to eliminate the boundary terms, which would interfere with obtaining useful relations. Using the relations we give compact explicit expressions for the n-gluon amplitudes with one negative-helicity gluon, up through n=7
Scalar one-loop vertex integrals as meromorphic functions of space-time dimension d
Energy Technology Data Exchange (ETDEWEB)
Bluemlein, Johannes [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Phan, Khiem Hong [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Vietnam National Univ., Ho Chi Minh City (Viet Nam). Univ. of Science; Riemann, Tord [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Silesia Univ., Chorzow (Poland). Inst. of Physics
2017-11-15
Representations are derived for the basic scalar one-loop vertex Feynman integrals as meromorphic functions of the space-time dimension d in terms of (generalized) hypergeometric functions {sub 2}F{sub 1} and F{sub 1}. Values at asymptotic or exceptional kinematic points as well as expansions around the singular points at d=4+2n, n non-negative integers, may be derived from the representations easily. The Feynman integrals studied here may be used as building blocks for the calculation of one-loop and higher-loop scalar and tensor amplitudes. From the recursion relation presented, higher n-point functions may be obtained in a straightforward manner.
String-inspired BCJ numerators for one-loop MHV amplitudes
International Nuclear Information System (INIS)
He, Song; Monteiro, Ricardo; Schlotterer, Oliver
2016-01-01
We find simple expressions for the kinematic numerators of one-loop MHV amplitudes in maximally supersymmetric Yang-Mills theory and supergravity, at any multiplicity. The gauge-theory numerators satisfy the Bern-Carrasco-Johansson (BCJ) duality between color and kinematics, so that the gravity numerators are simply the square of the gauge-theory ones. The duality holds because the numerators can be written in terms of structure constants of a kinematic algebra, which is familiar from the BCJ organization of self-dual gauge theory and gravity. The close connection that we find between one-loop amplitudes in the self-dual case and in the maximally supersymmetric case is reminiscent of the dimension-shifting formula. The starting point for arriving at our expressions is the dimensional reduction of ten-dimensional amplitudes obtained in the field-theory limit of open superstrings.
Checking the transverse Ward-Takahashi relation at one-loop order in four dimensions
International Nuclear Information System (INIS)
Pennington, M R; Williams, R
2006-01-01
Some time ago Takahashi derived the so-called transverse relations relating Green's functions of different orders to complement the well-known Ward-Green-Takahashi identities of gauge theories by considering wedge rather than inner products. These transverse relations have the potential to determine the full fermion-boson vertex in terms of the renormalization functions of the fermion propagator. He and Yu have given an indicative proof at one-loop level in four dimensions. However, their construct involves the fourth-rank Levi-Civita tensor defined only unambiguously in four dimensions exactly where the loop integrals diverge. Consequently, here we explicitly check the proposed transverse Ward-Takahashi relation holds at one-loop order in d-dimensions, with d = 4 + ε
One-loop Higgs plus four gluon amplitudes. Full analytic results
International Nuclear Information System (INIS)
Badger, Simon; Nigel Glover, E.W.; Williams, Ciaran; Mastrolia, Pierpaolo
2009-10-01
We consider one-loop amplitudes of a Higgs boson coupled to gluons in the limit of a large top quark mass. We treat the Higgs as the real part of a complex field φ that couples to the self-dual field strengths and compute the one-loop corrections to the φ-NMHV amplitude, which contains one gluon of positive helicity whilst the remaining three have negative helicity. We use four-dimensional unitarity to construct the cut-containing contributions and a hybrid of Feynman diagram and recursive based techniques to determine the rational piece. Knowledge of the φ-NMHV contribution completes the analytic calculation of the Higgs plus four gluon amplitude. For completeness we also include expressions for the remaining helicity configurations which have been calculated elsewhere. These amplitudes are relevant for Higgs plus jet production via gluon fusion in the limit where the top quark is large compared to all other scales in the problem. (orig.)
Transformation properties of the effective action for gauge theories
International Nuclear Information System (INIS)
Otten, C.M.E.
1978-01-01
The main purpose of this thesis is to investigate the gauge invariance properties of the effective action. In fact, the Slavnov-Taylor identities for the effective action are nothing but a compact formulation of the gauge symmetry properties of the theory. Chapter II of this thesis focuses on the derivation of the Slavnov-Taylor identities for a general gauge theory, especially the identities for proper vertices. An analysis of the group- and invariance structure of the effective action is given, using both diagrammatic and functional techniques. Moreover, the Slavnov-Taylor identities are written out explicitely up to the order g 4 , where g is the coupling constant of the theory. The general theory outlined in chapter II is applied to an SU(2) model containing vector bosons, scalar particles and leptons. Specifically, the interplay between finite one-loop effects and the invariance structure of the model is studied in a certain limit (the so-called large Higgs mass limit). It is shown that the results can be fully interpreted on the basis of the Slavnov-Taylor identities for proper vertices. This is done in chapter III. (Auth.)
One-loop corrections to the process e+e-→tt including hard bremsstrahlung
International Nuclear Information System (INIS)
Fleischer, J.; Riemann, T.; Werthenbach, A.; Leike, A.
2002-03-01
Radiative corrections to the process e + e - → t anti t are calculated in one-loop approximation of the Standard Model. There exist results from several groups. This talk provides further comparisons of the complete electroweak contributions, including hard bremsstrahlung. The excellent final agreement of the different groups allows to continue by working on a code for an event generator for TESLA and an extension to e + e - → 6 fermions. (orig.)
One-loop beta functions for the orientable non-commutative Gross Neveu model TH1"-->
Lakhoua, A.; Vignes-Tourneret, F.; Wallet, J.-C.
2007-11-01
We compute at the one-loop order the β-functions for a renormalisable non-commutative analog of the Gross Neveu model defined on the Moyal plane. The calculation is performed within the so called x-space formalism. We find that this non-commutative field theory exhibits asymptotic freedom for any number of colors. The β-function for the non-commutative counterpart of the Thirring model is found to be non vanishing.
One-loop renormalization and the properties of radiative corrections in the Fried-Yennie gauge
International Nuclear Information System (INIS)
Karshenbojm, S.G.; Shelyuto, V.A.; Ehjdes, M.I.
1988-01-01
One-loop radiative corrections in the Fried-Yennie gauge are investigated. It is shown that the usual on-mass-shell subtraction may be performed in this gauge without use of the infrared photon mass. The behaviour of the diagrams with corrections near the mass-shell is explored, this behaviour turns out to be in the Freid-Yennie gauge milder than in any other gauge and milder than the behaviour of the corresponding graphs without radiative corrections
One-loop fluctuation-dissipation formula for bubble-wall velocity
International Nuclear Information System (INIS)
Arnold, P.
1993-01-01
The limiting bubble wall velocity during a first-order electroweak phase transition is of interest in scenarios for electroweak baryogenesis. Khlebnikov has recently proposed an interesting method for computing this velocity based on the fluctuation-dissipation theorem. It is demonstrated that at one-loop order this method is identical to simple, earlier techniques for computing the wall velocity based on computing the friction from particles reflecting off or transmitting through the wall in the ideal gas limit
Reduction method for one-loop tensor 5- and 6-point integrals revisited
International Nuclear Information System (INIS)
Diakonidis, Theodoros
2009-01-01
A complete analytical reduction of general one-loop Feynman integrals with five legs for tensors up to rank R=3 and six legs for tensors up to rank 4 is reviewed. An elegant formalism with extensive use of signed minors was developed for the cancellation of leading inverse Gram determinants. The resulting compact formulae allow both for a study of analytical properties and for efficient numerical programming. Here some special numerical examples are presented. (orig.)
One-loop Renormalization of Resonance Chiral Theory with Scalar and Pseudoscalar Resonances
International Nuclear Information System (INIS)
Rosell, I.
2007-01-01
The divergent part of the generating functional of the Resonance Chiral Theory is evaluated up to one loop when one multiplet of scalar and pseudoscalar resonances are included and interaction terms which couple up to two resonances are considered. Hence we obtain the renormalization of the couplings of the initial Lagrangian and, moreover, the complete list of operators that make this theory finite, at this order
Reduction method for one-loop tensor 5- and 6-point integrals revisited
Energy Technology Data Exchange (ETDEWEB)
Diakonidis, Theodoros [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2009-01-15
A complete analytical reduction of general one-loop Feynman integrals with five legs for tensors up to rank R=3 and six legs for tensors up to rank 4 is reviewed. An elegant formalism with extensive use of signed minors was developed for the cancellation of leading inverse Gram determinants. The resulting compact formulae allow both for a study of analytical properties and for efficient numerical programming. Here some special numerical examples are presented. (orig.)
One-loop fluctuation-dissipation formula for bubble-wall velocity
International Nuclear Information System (INIS)
Arnold, P.
1993-01-01
The limiting bubble-wall velocity during a first-order electroweak phase transition is of interest in scenarios for electroweak baryogenesis. Khlebnikov has recently proposed an interesting method for computing this velocity based on the fluctuation-dissipation theorem. I demonstrate that at one-loop order this method is identical to simple, earlier techniques for computing the wall velocity based on computing the friction from particles reflecting off or transmitting through the wall in the ideal gas (''thin-wall'') limit
Unitarity cuts and Reduction to master integrals in d dimensions for one-loop amplitudes
Anastasiou, C; Feng, B; Kunszt, Z; Mastrolia, Pierpaolo; Anastasiou, Charalampos; Britto, Ruth; Feng, Bo; Kunszt, Zoltan; Mastrolia, Pierpaolo
2007-01-01
We present an alternative reduction to master integrals for one-loop amplitudes using a unitarity cut method in arbitrary dimensions. We carry out the reduction in two steps. The first step is a pure four-dimensional cut-integration of tree amplitudes with a mass parameter, and the second step is applying dimensional shift identities to master integrals. This reduction is performed at the integrand level, so that coefficients can be read out algebraically.
One-loop renormalisation for the second moment of GPDs with Wilson fermions
International Nuclear Information System (INIS)
Goeckeler, M.; Horsley, R.; Perlt, H.; Rakow, P.E.L.; Schaefer, A.; Schierholz, G.; Schiller, A.
2005-01-01
We calculate the non-forward quark matrix elements for operators with two covariant derivatives in one-loop lattice perturbation theory using Wilson fermions. These matrix elements are needed in the renormalisation of the second moment of generalised parton distributions measured in lattice QCD. For some commonly used representations of the hypercubic group we determine the sets of all mixing operators and find the matrices of mixing and renormalisation factors
On the tensor reduction of one-loop pentagons and hexagons
International Nuclear Information System (INIS)
Diakonidis, T.; Riemann, T.; Tausk, J.B.; Fleischer, J.; Bielefeld Univ.; Gluza, J.; Kajda, K.
2008-07-01
We perform analytical reductions of one-loop tensor integrals with 5 and 6 legs to scalar master integrals. They are based on the use of recurrence relations connecting integrals in different space-time dimensions. The reductions are expressed in a compact form in terms of signed minors, and have been implemented in a mathematica package called hexagon.m. We present several numerical examples. (orig.)
One-loop mass shifts in O(32) open superstring theory
International Nuclear Information System (INIS)
Yamamoto, Hisashi.
1987-08-01
One-loop amplitudes of O(N) open superstring with emission of massive bosons are studied. Divergences appearing at λ = 0 (λ: the over-all Teichmueller parameter) are shown to be canceled if N = 32 just as in the massless case. We explicitly evaluate the two-point on-shell amplitudes for all the levels of bosons lying on the leading (m 2 = 2 l, J = l + 1, m:mass J:spin l:level number of an excited state) and the next-to-leading (m 2 = 2 l, J = l) Regge trajectories and observe that they are nonvanishing even at N = 32. This implies that O(32) open super-string one-loop amplitudes with massive bosons generally suffer from external-line divergences. Further the obtained expressions of on-shell self energies (mass shifts δm 2 (l)) seem to have nontrivial dependences on l (being not proportional to l), although mass degeneracies remain. This strongly suggests that the Regge trajectories form a set of parallel polygonal lines at one-loop level so that the mass shifts cannot be absorbed by the shift of the slope parameter. The divergences would have to be cured by the vertex operator renormalizations at every excited level. (author)
Two-body decays of gluino at full one-loop level in the quark-flavour violating MSSM.
Eberl, Helmut; Ginina, Elena; Hidaka, Keisho
2017-01-01
We study the two-body decays of the gluino at full one-loop level in the Minimal Supersymmetric Standard Model with quark-flavour violation (QFV) in the squark sector. The renormalisation is done in the [Formula: see text] scheme. The gluon and photon radiations are included by adding the corresponding three-body decay widths. We discuss the dependence of the gluino decay widths on the QFV parameters. The main dependence stems from the [Formula: see text]-[Formula: see text] mixing in the decays to up-type squarks, and from the [Formula: see text]-[Formula: see text] mixing in the decays to down-type squarks due to the strong constraints from B-physics on the other quark-flavour-mixing parameters. The full one-loop corrections to the gluino decay widths are mostly negative and of the order of about -10%. The QFV part stays small in the total width but can vary up to -8% for the decay width into the lightest [Formula: see text] squark. For the corresponding branching ratio the effect is somehow washed out by at least a factor of two. The electroweak corrections can be as large as 35% of the SUSY QCD corrections.
2PI effective action for the SYK model and tensor field theories
Benedetti, Dario; Gurau, Razvan
2018-05-01
We discuss the two-particle irreducible (2PI) effective action for the SYK model and for tensor field theories. For the SYK model the 2PI effective action reproduces the bilocal reformulation of the model without using replicas. In general tensor field theories the 2PI formalism is the only way to obtain a bilocal reformulation of the theory, and as such is a precious instrument for the identification of soft modes and for possible holographic interpretations. We compute the 2PI action for several models, and push it up to fourth order in the 1 /N expansion for the model proposed by Witten in [1], uncovering a one-loop structure in terms of an auxiliary bilocal action.
Generic calculation of two-body partial decay widths at the full one-loop level
Goodsell, Mark D.; Liebler, Stefan; Staub, Florian
2017-11-01
We describe a fully generic implementation of two-body partial decay widths at the full one-loop level in the SARAH and SPheno framework compatible with most supported models. It incorporates fermionic decays to a fermion and a scalar or a gauge boson as well as scalar decays into two fermions, two gauge bosons, two scalars or a scalar and a gauge boson. We present the relevant generic expressions for virtual and real corrections. Whereas wave-function corrections are determined from on-shell conditions, the parameters of the underlying model are by default renormalised in a \\overline{ {DR}} (or \\overline{ {MS}}) scheme. However, the user can also define model-specific counter-terms. As an example we discuss the renormalisation of the electric charge in the Thomson limit for top-quark decays in the standard model. One-loop-induced decays are also supported. The framework additionally allows the addition of mass and mixing corrections induced at higher orders for the involved external states. We explain our procedure to cancel infrared divergences for such cases, which is achieved through an infrared counter-term taking into account corrected Goldstone boson vertices. We compare our results for sfermion, gluino and Higgs decays in the minimal supersymmetric standard model (MSSM) against the public codes SFOLD, FVSFOLD and HFOLD and explain observed differences. Radiatively induced gluino and neutralino decays are compared against the original implementation in SPheno in the MSSM. We exactly reproduce the results of the code CNNDecays for decays of neutralinos and charginos in R-parity violating models. The new version SARAH 4.11.0 by default includes the calculation of two-body decay widths at the full one-loop level. Current limitations for certain model classes are described.
Generic calculation of two-body partial decay widths at the full one-loop level
Energy Technology Data Exchange (ETDEWEB)
Goodsell, Mark D. [UPMC Univ. Paris 06 (France); Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France); Sorbonne Univ., Paris (France); Liebler, Stefan [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Staub, Florian [Karlsruhe Institute for Technology, Karlsruhe (Germany). Inst. for Theoretical Physics; Karlsruhe Institute for Technology, Eggenstein-Leopoldshafen (Germany). Inst. for Nuclear Physics
2017-04-15
We describe a fully generic implementation of two-body partial decay widths at the full one-loop level in the SARAH and SPheno framework compatible with most supported models. It incorporates fermionic decays to a fermion and a scalar or a gauge boson as well as scalar decays into two fermions, two gauge bosons, two scalars or a scalar and a gauge boson. We present the relevant generic expressions for virtual and real corrections. Whereas wavefunction corrections are determined from on-shell conditions, the parameters of the underlying model are by default renormalised in a DR (or MS) scheme. However, the user can also define model-specific counter-terms. As an example we discuss the renormalisation of the electric charge in the Thomson limit for top-quark decays in the standard model. One-loop induced decays are also supported. The framework additionally allows the addition of mass and mixing corrections induced at higher orders for the involved external states. We explain our procedure to cancel infra-red divergences for such cases, which is achieved through an infra-red counter-term taking into account corrected Goldstone boson vertices. We compare our results for sfermion, gluino and Higgs decays in the minimal supersymmetric standard model (MSSM) against the public codes SFOLD, FVSFOLD and HFOLD and explain observed differences. Radiative induced gluino and neutralino decays are compared against the original implementation in SPheno in the MSSM. We exactly reproduce the results of the code CNNDecays for decays of neutralinos and charginos in R-parity violating models. The new version SARAH 4.11.0 by default includes the calculation of two-body decay widths at the full one-loop level. Current limitations for certain model classes are described.
Generic calculation of two-body partial decay widths at the full one-loop level
Energy Technology Data Exchange (ETDEWEB)
Goodsell, Mark D. [Sorbonne Universites, UPMC Univ Paris 06, UMR 7589, LPTHE, Paris (France); CNRS, UMR 7589, LPTHE, Paris (France); Liebler, Stefan [DESY, Hamburg (Germany); Staub, Florian [Karlsruhe Institute of Technology, Institute for Theoretical Physics (ITP), Karlsruhe (Germany); Karlsruhe Institute of Technology, Institute for Nuclear Physics (IKP), Eggenstein-Leopoldshafen (Germany)
2017-11-15
We describe a fully generic implementation of two-body partial decay widths at the full one-loop level in the SARAH and SPheno framework compatible with most supported models. It incorporates fermionic decays to a fermion and a scalar or a gauge boson as well as scalar decays into two fermions, two gauge bosons, two scalars or a scalar and a gauge boson. We present the relevant generic expressions for virtual and real corrections. Whereas wave-function corrections are determined from on-shell conditions, the parameters of the underlying model are by default renormalised in a DR (or MS) scheme. However, the user can also define model-specific counter-terms. As an example we discuss the renormalisation of the electric charge in the Thomson limit for top-quark decays in the standard model. One-loop-induced decays are also supported. The framework additionally allows the addition of mass and mixing corrections induced at higher orders for the involved external states. We explain our procedure to cancel infrared divergences for such cases, which is achieved through an infrared counter-term taking into account corrected Goldstone boson vertices. We compare our results for sfermion, gluino and Higgs decays in the minimal supersymmetric standard model (MSSM) against the public codes SFOLD, FVSFOLD and HFOLD and explain observed differences. Radiatively induced gluino and neutralino decays are compared against the original implementation in SPheno in the MSSM. We exactly reproduce the results of the code CNNDecays for decays of neutralinos and charginos in R-parity violating models. The new version SARAH 4.11.0 by default includes the calculation of two-body decay widths at the full one-loop level. Current limitations for certain model classes are described. (orig.)
Generic calculation of two-body partial decay widths at the full one-loop level
International Nuclear Information System (INIS)
Goodsell, Mark D.; Liebler, Stefan; Staub, Florian; Karlsruhe Institute for Technology, Eggenstein-Leopoldshafen
2017-04-01
We describe a fully generic implementation of two-body partial decay widths at the full one-loop level in the SARAH and SPheno framework compatible with most supported models. It incorporates fermionic decays to a fermion and a scalar or a gauge boson as well as scalar decays into two fermions, two gauge bosons, two scalars or a scalar and a gauge boson. We present the relevant generic expressions for virtual and real corrections. Whereas wavefunction corrections are determined from on-shell conditions, the parameters of the underlying model are by default renormalised in a DR (or MS) scheme. However, the user can also define model-specific counter-terms. As an example we discuss the renormalisation of the electric charge in the Thomson limit for top-quark decays in the standard model. One-loop induced decays are also supported. The framework additionally allows the addition of mass and mixing corrections induced at higher orders for the involved external states. We explain our procedure to cancel infra-red divergences for such cases, which is achieved through an infra-red counter-term taking into account corrected Goldstone boson vertices. We compare our results for sfermion, gluino and Higgs decays in the minimal supersymmetric standard model (MSSM) against the public codes SFOLD, FVSFOLD and HFOLD and explain observed differences. Radiative induced gluino and neutralino decays are compared against the original implementation in SPheno in the MSSM. We exactly reproduce the results of the code CNNDecays for decays of neutralinos and charginos in R-parity violating models. The new version SARAH 4.11.0 by default includes the calculation of two-body decay widths at the full one-loop level. Current limitations for certain model classes are described.
One-loop corrections for e+e- annihilation into μ+μ- in the Weinberg model
Veltman, M.J.G.; Passarino, G.
1979-01-01
Analytical expressions for the cross section including all the one-loop radiative corrections in the context of the Weinberg model are presented. The systematic calculation of one-loop diagrams has been carried out using a recently proposed scheme. Numerical results are shown in a region from
Refined counting of necklaces in one-loop N=4 SYM
Suzuki, Ryo
2017-06-01
We compute the grand partition function of N=4 SYM at one-loop in the SU(2) sector with general chemical potentials, extending the results of Pólya's theorem. We make use of finite group theory, applicable to all orders of perturbative 1 /N c expansion. We show that only the planar terms contribute to the grand partition function, which is therefore equal to the grand partition function of an ensemble of {XXX}_{1/2} spin chains. We discuss how Hagedorn temperature changes on the complex plane of chemical potentials.
Colour decompositions of multi-quark one-loop QCD amplitudes
DEFF Research Database (Denmark)
Ita, Harald; Ozeren, Kemal
2012-01-01
We describe the decomposition of one-loop QCD amplitudes in terms of colour-ordered building blocks. We give new expressions for the coefficients of QCD colour structures in terms of ordered objects called primitive amplitudes, for processes with up to seven partons. These results are needed in c...... to the cross section for W+4-jet production at the Large Hadron Collider, and verify that it is very well approximated by keeping only the leading terms in an expansion around the formal limit of a large number of colours....
A general reduction method for one-loop N-point integrals
International Nuclear Information System (INIS)
Heinrich, G.; Binoth, T.
2000-01-01
In order to calculate cross sections with a large number of particles/jets in the final state at next-to-leading order, one has to reduce the occurring scalar and tensor one-loop integrals to a small set of known integrals. In massless theories, this reduction procedure is complicated by the presence of infrared divergences. Working in n = 4 - 2ε dimensions, it will be outlined how to achieve such a reduction for diagrams with an arbitrary number of external legs. As a result, any integral with more than four propagators and generic 4-dimensional external momenta can be reduced to box integrals
GoSam 2.0. Automated one loop calculations within and beyond the standard model
International Nuclear Information System (INIS)
Greiner, Nicolas; Deutsches Elektronen-Synchrotron
2014-10-01
We present GoSam 2.0, a fully automated framework for the generation and evaluation of one loop amplitudes in multi leg processes. The new version offers numerous improvements both on generational aspects as well as on the reduction side. This leads to a faster and more stable code for calculations within and beyond the Standard Model. Furthermore it contains the extended version of the standardized interface to Monte Carlo programs which allows for an easy combination with other existing tools. We briefly describe the conceptual innovations and present some phenomenological results.
One loop beta functions and fixed points in higher derivative sigma models
International Nuclear Information System (INIS)
Percacci, Roberto; Zanusso, Omar
2010-01-01
We calculate the one loop beta functions of nonlinear sigma models in four dimensions containing general two- and four-derivative terms. In the O(N) model there are four such terms and nontrivial fixed points exist for all N≥4. In the chiral SU(N) models there are in general six couplings, but only five for N=3 and four for N=2; we find fixed points only for N=2, 3. In the approximation considered, the four-derivative couplings are asymptotically free but the coupling in the two-derivative term has a nonzero limit. These results support the hypothesis that certain sigma models may be asymptotically safe.
A solution for tensor reduction of one-loop N-point functions with N{>=}6
Energy Technology Data Exchange (ETDEWEB)
Fleischer, J. [Bielefeld Univ. (Germany). Fakultaet fuer Physik; Riemann, T. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2011-11-15
Collisions at the LHC produce many-particle final states, and for precise predictions the one-loop N-point corrections are needed. We study here the tensor reduction for Feynman integrals with N{>=}6. A general, recursive solution by Binoth et al. expresses N-point Feynman integrals of rank R in terms of (N-1)-point Feynman integrals of rank (R-1) (for N{>=}6). We show that the coefficients can be obtained analytically from suitable representations of the metric tensor. Contractions of the tensor integrals with external momenta can be efficiently expressed as well. We consider our approach particularly well suited for automatization. (orig.)
The low energy expansion of the one-loop type II superstring amplitude
Green, Michael B.; Green, Michael B.; Vanhove, Pierre
2000-01-01
The one-loop four-graviton amplitude in either of the type II superstring theories is expanded in powers of the external momenta up to and including terms of order s^4 log s R^4, where R^4 denotes a specific contraction of four linearized Weyl tensors and s is a Mandelstam invariant. Terms in this series are obtained by integrating powers of the two-dimensional scalar field theory propagator over the toroidal world-sheet as well as the moduli of the torus. The values of these coefficients match expectations based on duality relations between string theory and eleven-dimensional supergravity.
Boundary string field theory and an open string one-loop
International Nuclear Information System (INIS)
Lee, Tae Jin; Viswanathan, K. S.; Yang, Yi
2003-01-01
We discuss the open string one-loop partition function in the tachyon condensation background of an unstable D-brane system. We evaluate the partition function by using the boundary-state formulation and find that it is in complete agreement with the result obtained in the boundary string field theory. This suggests that the open string higher loop diagrams may be produced consistently by using a closed string field theory, where the D-brane plays the role of a source for the closed string field
International Nuclear Information System (INIS)
De la Incera, V.; Ferrer, E.; Shalad, A.Y.
1987-01-01
A homogeneous and isotropic plasma made up of electrons and positrons is examined. The coefficients of the covariant expansion of the three-photon vertex are calculated in the one-loop approximation of the Green's function technique, together with the probability amplitudes of various processes involving three photons that produce information on the probability of the polarization states of the incoming and outgoing photons in the splitting process. The calculation results are used to verify the consequences of all exact symmetries which must be done for the vertex tensor. The case of a charge-symmetric plasma is considered together with the special case of photon collinearity
Lattice artifacts in the non-Abelian Debye screening mass in one-loop order
International Nuclear Information System (INIS)
Kaste, P.; Rothe, H.J.
1997-01-01
We compute the electric screening mass in lattice QCD with Wilson fermions at finite temperature and chemical potential to one-loop order, and show that lattice artifacts arising from a finite lattice spacing result in an enhancement of the screening mass as compared to the continuum. We discuss the magnitude of this enhancement as a function of the temperature and chemical potential for lattices with a different number of lattice sites in the temporal direction that can be implemented in lattice simulations. Most of the enhancement is found to be due to the fermion loop contribution. copyright 1997 The American Physical Society
On one-loop corrections to matching conditions of lattice HQET including 1/m{sub b} terms
Energy Technology Data Exchange (ETDEWEB)
Korcyl, Piotr [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2013-12-15
HQET is an effective theory for QCD with N{sub f} light quarks and a massive valence quark if the mass of the latter is much bigger than LQCD. As any effective theory, HQET is predictive only when a set of parameters has been determined through a process called matching. The non-perturbative matching procedure including 1/m{sub b} terms, developed by the ALPHA collaboration, consists of 19 carefully chosen observables which are precisely computable in lattice QCD as well as in lattice HQET. The matching conditions are then a set of 19 equations which relate the QCD and HQET values of these observables. We present a study of one-loop corrections to two generic matching observables involving correlation function with an insertion of the A{sub 0} operator. Our results enable us to quantify the quality of the relevant observables in view of the envisaged nonperturbative implementation of this matching procedure.
Scalar one-loop integrals using the negative-dimension approach
International Nuclear Information System (INIS)
Anastasiou, C.; Glover, E.W.N.; Oleari, C.
2000-01-01
We study massive one-loop integrals by analytically continuing the Feynman integral to negative dimensions as advocated by Halliday and Ricotta and developed by Suzuki and Schmidt. We consider n-point one-loop integrals with arbitrary powers of propagators in general dimension D. For integrals with m mass scales and q external momentum scales, we construct a template solution valid for all n which allows us to obtain a representation of the graph in terms of a finite sum of generalised hypergeometric functions with m+q-1 variables. All solutions for all possible kinematic regions are given simultaneously, allowing the investigation of different ranges of variation of mass and momentum scales. As a first step, we develop the general framework and apply it to massive bubble and vertex integrals. Of course many of these integrals are well known and we show that the known results are recovered. To give a concrete new result, we present expressions for the general vertex integral with one off-shell leg and two internal masses in terms of hypergeometric functions of two variables that converge in the appropriate kinematic regions. The kinematic singularity structure of this graph is sufficiently complex to give insight into how the negative-dimension method operates and gives some hope that more complicated graphs can also be evaluated
Massless spectra and gauge couplings at one-loop on non-factorisable toroidal orientifolds
Berasaluce-González, Mikel; Honecker, Gabriele; Seifert, Alexander
2018-01-01
So-called 'non-factorisable' toroidal orbifolds can be rewritten in a factorised form as a product of three two-tori by imposing an additional shift symmetry. This finding of Blaszczyk et al. [1] provides a new avenue to Conformal Field Theory methods, by which the vector-like massless matter spectrum - and thereby the type of gauge group enhancement on orientifold invariant fractional D6-branes - and the one-loop corrections to the gauge couplings in Type IIA orientifold theories can be computed in addition to the well-established chiral matter spectrum derived from topological intersection numbers among three-cycles. We demonstrate this framework for the Z4 × ΩR orientifolds on the A3 ×A1 ×B2-type torus. As observed before for factorisable backgrounds, also here the one-loop correction can drive the gauge groups to stronger coupling as demonstrated by means of a four-generation Pati-Salam example.
Reduction formalism for dimensionally regulated one-loop N-point integrals
International Nuclear Information System (INIS)
Binoth, T.; Guillet, J.Ph.; Heinrich, G.
2000-01-01
We consider one-loop scalar and tensor integrals with an arbitrary number of external legs relevant for multi-parton processes in massless theories. We present a procedure to reduce N-point scalar functions with generic 4-dimensional external momenta to box integrals in (4-2ε) dimensions. We derive a formula valid for arbitrary N and give an explicit expression for N=6. Further a tensor reduction method for N-point tensor integrals is presented. We prove that generically higher dimensional integrals contribute only to order ε for N≥5. The tensor reduction can be solved iteratively such that any tensor integral is expressible in terms of scalar integrals. Explicit formulas are given up to N=6
NGluon. A package to calculate one-loop multi-gluon amplitudes
International Nuclear Information System (INIS)
Badger, S.; Niels Bohr Institute, Copenhagen; Biedermann, B.; Uwer, P.
2010-11-01
We present a computer library for the numerical evaluation of colour-ordered n-gluon amplitudes at one-loop order in pure Yang-Mills theory. The library uses the recently developed technique of generalised unitarity. Running in double precision the library yields reliable results for up to 14 gluons with only a small fraction of events requiring a re-evaluation using extended floating point arithmetic. We believe that the library presented here provides an important contribution to future LHC phenomenology. The program may also prove useful in cross checking results obtained by other methods. In addition, the code provides a sample implementation which may serve as a starting point for further developments. (orig.)
Discussion on some one-loop induced flavour-changing decays
International Nuclear Information System (INIS)
Wang Jianxiong; Chang Chaohsi
1990-08-01
We calculate the one-loop flavour-changing processes Z 0 → bs-bar, B s(d) → X + γγ, B s → γγ and B s → gg in the Standard Model, provided t quark mass is very heavy, and obtain Br(B s (d) → X + γγ) ∼ 10 -5 , Br(B s → γγ) ∼ 10 -6 and Br(B s → gg) ∼ 10 -5 . The branching ratios increase 2-4 times as m t from 80 to 240 GeV. The results show that the contribution from t quark-loop is dominant. (author). 4 refs
One-loop fermion contribution in an asymmetric lattice regularization of SU(N) gauge theories
International Nuclear Information System (INIS)
Trinchero, R.C.
1983-01-01
Using the background field method we calculate the one-loop fermion corrections in an asymmetric lattice version of SU(N) gauge theories with massless fermions. The introduction of different lattice spacings for spatial (a) and temporal (a 4 ) links requires the introduction of two different bare coupling constants, gsub(sigma) and gsub(tau). Our calculation provides the value of the derivatives of the couplings with respect to xi=a/a 4 at xi=1; these derivatives are of particular relevance for finite-temperature lattice calculations. With xi->infinite, the lattice hamiltonian version is obtained, and the ratio of scale parameters Λsub(H)/Λsub(E) is calculated. (orig.)
NGluon. A package to calculate one-loop multi-gluon amplitudes
Energy Technology Data Exchange (ETDEWEB)
Badger, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Niels Bohr Institute, Copenhagen (Denmark). Niels Bohr International Academy and Discovery Center; Biedermann, B.; Uwer, P. [Humboldt Univ., Berlin (Germany). Inst. fuer Physik
2010-11-15
We present a computer library for the numerical evaluation of colour-ordered n-gluon amplitudes at one-loop order in pure Yang-Mills theory. The library uses the recently developed technique of generalised unitarity. Running in double precision the library yields reliable results for up to 14 gluons with only a small fraction of events requiring a re-evaluation using extended floating point arithmetic. We believe that the library presented here provides an important contribution to future LHC phenomenology. The program may also prove useful in cross checking results obtained by other methods. In addition, the code provides a sample implementation which may serve as a starting point for further developments. (orig.)
One-loop potential in the new string model with negative stiffness
International Nuclear Information System (INIS)
Kleinert, H.; Chervyakov, A.M.; Nesterenko, V.V.
1996-01-01
The color-electric flux tube between quarks has a finite thickness therefore also a finite curvature stiffness. Contrary to earlier rigid-string proposal by Polyakov and Kleinert and motivated by the properties of a magnetic flux tube in a type-II superconductor, we put forward the hypothesis that the stiffness is negative. We set up and study the properties of an idealized string model with such negative stiffness. In contrast to the rigid string, the propagator in the new model has no unphysical pole. One-loop calculations show that the model generates an interquark potential which does not contain the square root singularity even for moderate values of a negative stiffness. At large distances, the potential has usual linearly rising term with the universal Luescher correction
One-loop contributions to neutral Higgs decay h→μτ
International Nuclear Information System (INIS)
Phan, K. H.; Hung, H.T.; Hue, L.T.
2016-01-01
In calculating one-loop contributions to amplitudes of the lepton-flavor violating decays of the neutral Higgses (LFVHD) to different flavor charged leptons, the analytic expressions can be written in term of Passarino–Veltman functions. Then, they can be computed numerically by LoopTools [1]. Another approach is using suitable analytic expressions established for just this particular case. We compare numerical results obtained from LoopTools and those computed by different expressions that have been applied recently. Then we derive the preferable ones that are applicable for large ranges of free parameters introduced in extensions of the standard model. For illustration, the LFVHD in a simple model, which has been discussed recently, will be investigated more precisely.
A simple method for one-loop renormalization in curved space-time
Energy Technology Data Exchange (ETDEWEB)
Markkanen, Tommi [Helsinki Institute of Physics and Department of Physics, P.O. Box 64, FI-00014, University of Helsinki (Finland); Tranberg, Anders, E-mail: tommi.markkanen@helsinki.fi, E-mail: anders.tranberg@uis.no [Niels Bohr International Academy and Discovery Center, Niels Bohr Institute, Blegdamsvej 17, 2100 Copenhagen (Denmark)
2013-08-01
We present a simple method for deriving the renormalization counterterms from the components of the energy-momentum tensor in curved space-time. This method allows control over the finite parts of the counterterms and provides explicit expressions for each term separately. As an example, the method is used for the self-interacting scalar field in a Friedmann-Robertson-Walker metric in the adiabatic approximation, where we calculate the renormalized equation of motion for the field and the renormalized components of the energy-momentum tensor to fourth adiabatic order while including interactions to one-loop order. Within this formalism the trace anomaly, including contributions from interactions, is shown to have a simple derivation. We compare our results to those obtained by two standard methods, finding agreement with the Schwinger-DeWitt expansion but disagreement with adiabatic subtractions for interacting theories.
Low-energy effective action in two-dimensional SQED: a two-loop analysis
Samsonov, I. B.
2017-07-01
We study two-loop quantum corrections to the low-energy effective actions in N=(2,2) and N=(4,4) SQED on the Coulomb branch. In the latter model, the low-energy effective action is described by a generalized Kähler potential which depends on both chiral and twisted chiral superfields. We demonstrate that this generalized Kähler potential is one-loop exact and corresponds to the N=(4,4) sigma-model with torsion presented by Roček, Schoutens and Sevrin [1]. In the N=(2,2) SQED, the effective Kähler potential is not protected against higher-loop quantum corrections. The two-loop quantum corrections to this potential and the corresponding sigma-model metric are explicitly found.
{Delta}r in the Two-Higgs-Doublet Model at full one loop level - and beyond
Energy Technology Data Exchange (ETDEWEB)
Lopez-Val, David [Universitaet Heidelberg, Institut fuer Theoretische Physik, Heidelberg (Germany); Sola, Joan [Universitat de Barcelona, Dept. Estructura i Constituents de la Materia, Barcelona, Catalonia (Spain); Institut de Ciencies del Cosmos, Barcelona, Catalonia (Spain)
2013-04-15
After the recent discovery of a Higgs-like boson particle at the CERN LHC-collider, it becomes more necessary than ever to prepare ourselves for identifying its standard or non-standard nature. The fundamental parameter {Delta}r, relating the values of the electroweak gauge boson masses and the Fermi constant, is the traditional observable encoding high precision information of the quantum effects. In this work we present a complete quantitative study of {Delta}r in the framework of the general Two-Higgs-Doublet Model (2HDM). While the one-loop analysis of {Delta}r in this model was carried out long ago, in the first part of our work we consistently incorporate the higher order effects that have been computed since then for the SM part of {Delta}r. Within the on-shell scheme, we find typical corrections leading to shifts of {proportional_to}20-40 MeV on the W mass, resulting in a better agreement with its experimentally measured value and in a degree no less significant than in the MSSM case. In the second part of our study we devise a set of effective couplings that capture the dominant higher order genuine 2HDM quantum effects on the {delta}{rho} part of {Delta}r in the limit of large Higgs boson self-interactions. This limit constitutes a telltale property of the general 2HDM which is unmatched by e.g. the MSSM. (orig.)
Δr in the Two-Higgs-Doublet Model at full one loop level - and beyond
International Nuclear Information System (INIS)
Lopez-Val, David; Sola, Joan
2013-01-01
After the recent discovery of a Higgs-like boson particle at the CERN LHC-collider, it becomes more necessary than ever to prepare ourselves for identifying its standard or non-standard nature. The fundamental parameter Δr, relating the values of the electroweak gauge boson masses and the Fermi constant, is the traditional observable encoding high precision information of the quantum effects. In this work we present a complete quantitative study of Δr in the framework of the general Two-Higgs-Doublet Model (2HDM). While the one-loop analysis of Δr in this model was carried out long ago, in the first part of our work we consistently incorporate the higher order effects that have been computed since then for the SM part of Δr. Within the on-shell scheme, we find typical corrections leading to shifts of ∝20-40 MeV on the W mass, resulting in a better agreement with its experimentally measured value and in a degree no less significant than in the MSSM case. In the second part of our study we devise a set of effective couplings that capture the dominant higher order genuine 2HDM quantum effects on the δρ part of Δr in the limit of large Higgs boson self-interactions. This limit constitutes a telltale property of the general 2HDM which is unmatched by e.g. the MSSM. (orig.)
Multi-leg one-loop gravity amplitudes from gauge theory
International Nuclear Information System (INIS)
Bern, Z.; Dixon, L.; Perelstein, M.; Rozowsky, J.S.
1999-01-01
By exploiting relations between gravity and gauge theories, we present two infinite sequences of one-loop n-graviton scattering amplitudes: the 'maximally helicity-violating' amplitudes in N = 8 supergravity, and the 'all-plus' helicity amplitudes in gravity with any minimally coupled massless matter content. The all-plus amplitudes correspond to self-dual field configurations and vanish in supersymmetric theories. We make use of the tree-level Kawai-Lewellen-Tye (KLT) relations between open and closed string theory amplitudes, which in the low-energy limit imply relations between gravity and gauge theory tree amplitudes. For n ≤ 6, we determine the all-plus amplitudes explicitly from their unitarity cuts. The KLT relations, applied to the cuts, allow us to extend to gravity a previously found 'dimension-shifting' relation between (the cuts of) the all-plus amplitudes in gauge theory and the maximally helicity-violating amplitudes in N = 4 super-Yang-Mills theory. The gravitational version of the relation lets us determine the n ≤ 6N = 8 supergravity amplitudes from the all-plus gravity amplitudes. We infer the two series of amplitudes for all n from their soft and collinear properties, which can also be derived from gauge theory using the KLT relations
A complete algebraic reduction of one-loop tensor Feynman integrals
Energy Technology Data Exchange (ETDEWEB)
Fleischer, J. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Bielefeld Univ. (Germany). Fakultaet fuer Physik; Riemann, T. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2010-09-15
Guided by the need to eliminate inverse Gram determinants (){sub 5} from tensorial 5-point functions and sub-Gram determinants (){sub 4} from tensorial 4-point functions, we set up a new and very efficient approach for the tensor reduction of Feynman integrals. We eliminate all Gram determinants for one-loop 5-point integrals up to tensors of rank R=5 by reducing their tensor coefficients to higherdimensional 4-point tensor coefficients. These in turn are reduced to expressions which are free of inverse powers of (){sub 4}, but depend on higher-dimensional integrals I{sub 4}{sup (d)} with d{<=}2R. Their expression in terms of scalar integrals defined in the generic dimension, I{sub 4}; I{sub 3}; I{sub 2}; I{sub 1}, however, introduces coefficients [1=(){sub 4}]{sup R} for tensors of rank R. For small or vanishing (){sub 4}, an efficient expansion is found so that a stable numerical evaluation of massive and massless Feynman integrals at arbitrary values of the Gram determinants is made possible. Finally, some relations are mentioned which may be useful for analytic simplifications of the original Feynman diagrams. (orig.)
One-loop topological expansion for spin glasses in the large connectivity limit
Chiara Angelini, Maria; Parisi, Giorgio; Ricci-Tersenghi, Federico
2018-01-01
We apply for the first time a new one-loop topological expansion around the Bethe solution to the spin-glass model with a field in the high connectivity limit, following the methodological scheme proposed in a recent work. The results are completely equivalent to the well-known ones, found by standard field-theoretical expansion around the fully connected model (Bray and Roberts 1980, and following works). However this method has the advantage that the starting point is the original Hamiltonian of the model, with no need to define an associated field theory, nor to know the initial values of the couplings, and the computations have a clear and simple physical meaning. Moreover this new method can also be applied in the case of zero temperature, when the Bethe model has a transition in field, contrary to the fully connected model that is always in the spin-glass phase. Sharing with finite-dimensional model the finite connectivity properties, the Bethe lattice is clearly a better starting point for an expansion with respect to the fully connected model. The present work is a first step towards the generalization of this new expansion to more difficult and interesting cases as the zero-temperature limit, where the expansion could lead to different results with respect to the standard one.
Quantum effective action in spacetimes with branes and boundaries
International Nuclear Information System (INIS)
Barvinsky, A.O.; Nesterov, D.V.
2006-01-01
We construct quantum effective action in spacetime with branes/boundaries. This construction is based on the reduction of the underlying Neumann type boundary value problem for the propagator of the theory to that of the much more manageable Dirichlet problem. In its turn, this reduction follows from the recently suggested Neumann-Dirichlet duality which we extend beyond the tree-level approximation. In the one-loop approximation this duality suggests that the functional determinant of the differential operator subject to Neumann boundary conditions factorizes into the product of its Dirichlet counterpart and the functional determinant of a special operator on the brane--the inverse of the brane-to-brane propagator. As a byproduct of this relation we suggest a new method for surface terms of the heat kernel expansion. This method allows one to circumvent well-known difficulties in the heat kernel theory on manifolds with boundaries for a wide class of generalized Neumann boundary conditions. In particular, we easily recover several lowest-order surface terms in the case of Robin and oblique boundary onditions. We briefly discuss multiloop applications of the suggested Dirichlet reduction and the prospects of constructing the universal background-field method for systems with branes/boundaries, analogous to the Schwinger-DeWitt technique
International Nuclear Information System (INIS)
Hart, A.; Horgan, R.R.
2008-12-01
We perform a perturbative calculation of the influence of dynamical HISQ fermions on the perturbative improvement of the gluonic action in the same way as we have previously done for asqtad fermions. We nd the fermionic contributions to the radiative corrections in the Luescher-Weisz gauge action to be somewhat larger for HISQ fermions than for asqtad. Using one-loop perturbation theory as a test, we estimate that omission of the fermion-induced radiative corrections in dynamical asqtad simulations will give a measurable effect. The one-loop result gives a systematic shift of about -0:6% in r 1 on the coarsest asqtad improved staggered ensembles. This is the correct sign and magnitude to explain the scaling violations seen in Φ B on dynamical lattice ensembles. (orig.)
The one-loop partition function of N=4 super-Yang-Mills theory on RxS3
International Nuclear Information System (INIS)
Spradlin, Marcus; Volovich, Anastasia
2005-01-01
We study weakly coupled SU(N)N=4 super-Yang-Mills theory on RxS 3 at infinite N, which has interesting thermodynamics, including a Hagedorn transition, even at zero Yang-Mills coupling. We calculate the exact one-loop partition function below the Hagedorn temperature. Our calculation employs the representation of the one-loop dilatation operator as a spin chain Hamiltonian acting on neighboring sites and a generalization of Polya's counting of necklaces (gauge-invariant operators) to include necklaces with a 'pendant' (an operator which acts on neighboring beads). We find that the one-loop correction to the Hagedorn temperature is δlnT H =+λ/8π 2
Three- and two-point one-loop integrals in heavy particle effective theories
International Nuclear Information System (INIS)
Bouzas, A.O.
2000-01-01
We give a complete analytical computation of three- and two-point loop integrals occurring in heavy particle theories, involving a velocity change, for arbitrary real values of the external masses and residual momenta. (orig.)
Ryuichi, TAKAHASHI; Department of Physics and Astrophysics, Nagoya University
2008-01-01
We investigate the third-order density perturbation and the one-loop correction to the linear power spectrum in the dark-energy cosmological model. Our main interest is to understand the dark-energy effect on baryon acoustic oscillations in a quasi-nonlinear regime (k≈0.1h/Mpc). Analytical solutions and simple fitting formulae are presented for the dark-energy model with the general time-varying equation of state w(a). It turns out that the power spectrum coincides with the approximate res...
Moduli effective action in warped brane-world compactifications
International Nuclear Information System (INIS)
Garriga, Jaume; Pujolas, Oriol; Tanaka, Takahiro
2003-01-01
We consider a class of 5D brane-world solutions with a power-law warp factor a(y)∝y q , and bulk dilaton with profile phi∝lny, where y is the proper distance in the extra dimension. This class includes the heterotic M-theory brane-world of [Phys. Rev. D 59 (1999) 086001, and] and the Randall-Sundrum (RS) model as a limiting case. In general, there are two moduli fields y ± , corresponding to the 'positions' of two branes (which live at the fixed points of an orbifold compactification). Classically, the moduli are massless, due to a scaling symmetry of the action. However, in the absence of supersymmetry, they develop an effective potential at one loop. Local terms proportional to K ± 4 , where K ± =q/y ± is the local curvature scale at the location of the corresponding brane, are needed in order to remove the divergences in the effective potential. Such terms break the scaling symmetry and hence they may act as stabilizers for the moduli. When the branes are very close to each other, the effective potential induced by massless bulk fields behaves like V∼d -4 , where d is the separation between branes. When the branes are widely separated, the potentials for each one of the moduli generically develop a 'Coleman-Weinberg'-type behaviour of the form a 4 (y ± )K ± 4 ln(K ± /μ ± ), where μ ± are renormalization scales. In the RS case, the bulk geometry is AdS and K ± are equal to a constant, independent of the position of the branes, so these terms do not contribute to the mass of the moduli. However, for generic warp factor, they provide a simple stabilization mechanism. For q > or approx. 10, the observed hierarchy can be naturally generated by this potential, giving the lightest modulus a mass of order m - < or approx. TeV
String states, loops and effective actions in noncommutative field theory and matrix models
Directory of Open Access Journals (Sweden)
Harold C. Steinacker
2016-09-01
Full Text Available Refining previous work by Iso, Kawai and Kitazawa, we discuss bi-local string states as a tool for loop computations in noncommutative field theory and matrix models. Defined in terms of coherent states, they exhibit the stringy features of noncommutative field theory. This leads to a closed form for the 1-loop effective action in position space, capturing the long-range non-local UV/IR mixing for scalar fields. The formalism applies to generic fuzzy spaces. The non-locality is tamed in the maximally supersymmetric IKKT or IIB model, where it gives rise to supergravity. The linearized supergravity interactions are obtained directly in position space at one loop using string states on generic noncommutative branes.
String states, loops and effective actions in noncommutative field theory and matrix models
Energy Technology Data Exchange (ETDEWEB)
Steinacker, Harold C., E-mail: harold.steinacker@univie.ac.at
2016-09-15
Refining previous work by Iso, Kawai and Kitazawa, we discuss bi-local string states as a tool for loop computations in noncommutative field theory and matrix models. Defined in terms of coherent states, they exhibit the stringy features of noncommutative field theory. This leads to a closed form for the 1-loop effective action in position space, capturing the long-range non-local UV/IR mixing for scalar fields. The formalism applies to generic fuzzy spaces. The non-locality is tamed in the maximally supersymmetric IKKT or IIB model, where it gives rise to supergravity. The linearized supergravity interactions are obtained directly in position space at one loop using string states on generic noncommutative branes.
GoSam-2.0. A tool for automated one-loop calculations within the Standard Model and beyond
International Nuclear Information System (INIS)
Cullen, Gavin; Deurzen, Hans van; Greiner, Nicolas
2014-05-01
We present the version 2.0 of the program package GoSam for the automated calculation of one-loop amplitudes. GoSam is devised to compute one-loop QCD and/or electroweak corrections to multi-particle processes within and beyond the Standard Model. The new code contains improvements in the generation and in the reduction of the amplitudes, performs better in computing time and numerical accuracy, and has an extended range of applicability. The extended version of the ''Binoth-Les-Houches-Accord'' interface to Monte Carlo programs is also implemented. We give a detailed description of installation and usage of the code, and illustrate the new features in dedicated examples.
Fröb, Markus B.
2018-02-01
We study a proposal for gauge-invariant correlation functions in perturbative quantum gravity, which are obtained by fixing the geodesic distance between points in the fluctuating geometry. These correlation functions are non-local and strongly divergent, and we show how to renormalise them by performing a ‘wave function renormalisation’ of the geodesic embedding coordinates. The result is finite and gauge-independent, but displays unusual features such as double logarithms at one-loop order.
Hikage, Chiaki; Koyama, Kazuya; Heavens, Alan
2017-08-01
We compute the power spectrum at one-loop order in standard perturbation theory for the matter density field to which a standard Lagrangian baryonic acoustic oscillation (BAO) reconstruction technique is applied. The BAO reconstruction method corrects the bulk motion associated with the gravitational evolution using the inverse Zel'dovich approximation (ZA) for the smoothed density field. We find that the overall amplitude of one-loop contributions in the matter power spectrum substantially decreases after reconstruction. The reconstructed power spectrum thereby approaches the initial linear spectrum when the smoothed density field is close enough to linear, i.e., the smoothing scale Rs≳10 h-1 Mpc . On smaller Rs, however, the deviation from the linear spectrum becomes significant on large scales (k ≲Rs-1 ) due to the nonlinearity in the smoothed density field, and the reconstruction is inaccurate. Compared with N-body simulations, we show that the reconstructed power spectrum at one-loop order agrees with simulations better than the unreconstructed power spectrum. We also calculate the tree-level bispectrum in standard perturbation theory to investigate non-Gaussianity in the reconstructed matter density field. We show that the amplitude of the bispectrum significantly decreases for small k after reconstruction and that the tree-level bispectrum agrees well with N-body results in the weakly nonlinear regime.
International Nuclear Information System (INIS)
Ibarra, Alejandro; Wild, Sebastian
2015-01-01
We analyze the direct detection signals of a toy model consisting of a Dirac dark matter particle which couples to one Standard Model fermion via a scalar mediator. For all scenarios, the dark matter particle scatters off nucleons via one loop-induced electromagnetic and electroweak moments, as well as via the one-loop exchange of a Higgs boson. Besides, and depending on the details of the model, the scattering can also be mediated at tree level via the exchange of the scalar mediator or at one loop via gluon-gluon interactions. We show that, for thermally produced dark matter particles, the current limits from the LUX experiment on these scenarios are remarkably strong, even for dark matter coupling only to leptons. We also discuss future prospects for XENON1T and DARWIN and we argue that multi-ton xenon detectors will be able to probe practically the whole parameter space of the model consistent with thermal production and perturbativity. We also discuss briefly the implications of our results for the dark matter interpretation of the Galactic GeV excess
Wilsonian effective action of superstring theory
Energy Technology Data Exchange (ETDEWEB)
Sen, Ashoke [Harish-Chandra Research Institute,Chhatnag Road, Jhusi, Allahabad 211019 (India); Homi Bhabha National Institute,Training School Complex, Anushakti Nagar, Mumbai 400085 (India)
2017-01-25
By integrating out the heavy fields in type II or heterotic string field theory one can construct the effective action for the light fields. This effective theory inherits all the algebraic structures of the parent theory and the effective action automatically satisfies the Batalin-Vilkovisky quantum master equation. This theory is manifestly ultraviolet finite, has only light fields as its explicit degrees of freedom, and the Feynman diagrams of this theory reproduce the exact scattering amplitudes of light states in string theory to any arbitrary order in perturbation theory. Furthermore in this theory the degrees of freedom of light fields above certain energy scale are also implicitly integrated out. This energy scale is determined by a particular parameter labelling a family of equivalent actions, and can be made arbitrarily low, leading to the interpretation of the effective action as the Wilsonian effective action.
One-loop pure-gravity contributions to a black-hole geometry with quantum fluctuations
International Nuclear Information System (INIS)
Peterkin, R.E.
1985-01-01
A black-hole is unstable to zero-means quantum fluctuations of its metric. These quantum fluctuations break the degeneracy of the locations of the event-horizon and the apparent-horizon for a Schwarzschild black-hole. The path-integral in spacetime with Euclidean signature is calculated from the ADM action to second order in the variations. It is found that the second-order term of this perturbation expansion gives the same contribution to the path-integral as the zeroth-order term for these particular fluctuations. A surface near the black-hole event-horizon is correctly treated as a boundary, and this surface makes a substantial contribution to the path-integral. One may treat this path-integral as a partition function and calculate thermodynamic quantities. The entropy of this black-hole, for example, is found to be close to the accepted value of A/4h, where A is the black-hole surface area. The meaning of these particular fluctuations and the importance of the boundary near the event-horizon is discussed
Nambu sigma model and effective membrane actions
Energy Technology Data Exchange (ETDEWEB)
Jurco, Branislav, E-mail: jurco@karlin.mff.cuni.cz [Mathematical Institute, Charles University, Prague 186 75 (Czech Republic); Schupp, Peter, E-mail: p.schupp@jacobs-university.de [Jacobs University Bremen, 28759 Bremen (Germany); Maxwell Institute for Mathematical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, Scotland (United Kingdom)
2012-07-09
We propose an effective action for a p{sup Prime }-brane with open p-branes ending on it. The action has dual descriptions similar to the commutative and non-commutative ones of the DBI action for D-branes and open strings. The Poisson structure governing the non-commutativity of the D-brane is replaced by a Nambu structure and the open-closed string relations are generalized to the case of p-branes utilizing a novel Nambu sigma model description of p-branes. In the case of an M5-brane our action interpolates between M5-actions already proposed in the literature and matrix-model like actions involving Nambu structures.
Nambu sigma model and effective membrane actions
International Nuclear Information System (INIS)
Jurčo, Branislav; Schupp, Peter
2012-01-01
We propose an effective action for a p ′ -brane with open p-branes ending on it. The action has dual descriptions similar to the commutative and non-commutative ones of the DBI action for D-branes and open strings. The Poisson structure governing the non-commutativity of the D-brane is replaced by a Nambu structure and the open-closed string relations are generalized to the case of p-branes utilizing a novel Nambu sigma model description of p-branes. In the case of an M5-brane our action interpolates between M5-actions already proposed in the literature and matrix-model like actions involving Nambu structures.
Full One-loop Electro-Weak Corrections to Three-jet Observables at the Z pole and Beyond
Calame, C M Carloni; Piccinini, F; Ross, D A
2009-01-01
We describe the impact of the full one-loop EW terms of O(alpha_s alpha_EM^3) entering the electron-positron into three-jet cross-section from \\sqrt{s}=M_Z to TeV scale energies. We include both factorisable and non-factorisable virtual corrections, photon bremsstrahlung but not the real emission of W and Z bosons. Their importance for the measurement of alpha_S from jet rates and shape variables is explained qualitatively and illustrated quantitatively.
A RETRAN-02 model of the Sizewell B PCSR design - the Winfrith one-loop model, version 3.0
International Nuclear Information System (INIS)
Kinnersly, S.R.
1983-11-01
A one-loop RETRAN-02 model of the Sizewell B Pre Construction Safety Report (PCSR) design, set up at Winfrith, is described and documented. The model is suitable for symmetrical pressurised transients. Comparison with data from the Sizewell B PCSR shows that the model is a good representation of that design. Known errors, limitations and deficiencies are described. The mode of storage and maintenance at Winfrith using PROMUS (Program Maintenance and Update System) is noted. It is recommended that users modify the standard data by adding replacement cards to the end so as to aid in identification, use and maintenance of local versions. (author)
Package-X 2.0: A Mathematica package for the analytic calculation of one-loop integrals
Patel, Hiren H.
2017-09-01
This article summarizes new features and enhancements of the first major update of Package-X. Package-X 2.0 can now generate analytic expressions for arbitrarily high rank dimensionally regulated tensor integrals with up to four distinct propagators, each with arbitrary integer weight, near an arbitrary even number of spacetime dimensions, giving UV divergent, IR divergent, and finite parts at (almost) any real-valued kinematic point. Additionally, it can generate multivariable Taylor series expansions of these integrals around any non-singular kinematic point to arbitrary order. All special functions and abbreviations output by Package-X 2.0 support Mathematica's arbitrary precision evaluation capabilities to deal with issues of numerical stability. Finally, tensor algebraic routines of Package-X have been polished and extended to support open fermion chains both on and off shell. The documentation (equivalent to over 100 printed pages) is accessed through Mathematica's Wolfram Documentation Center and contains information on all Package-X symbols, with over 300 basic usage examples, 3 project-scale tutorials, and instructions on linking to FEYNCALC and LOOPTOOLS. Program files doi:http://dx.doi.org/10.17632/yfkwrd4d5t.1 Licensing provisions: CC by 4.0 Programming language: Mathematica (Wolfram Language) Journal reference of previous version: H. H. Patel, Comput. Phys. Commun 197, 276 (2015) Does the new version supersede the previous version?: Yes Summary of revisions: Extension to four point one-loop integrals with higher powers of denominator factors, separate extraction of UV and IR divergent parts, testing for power IR divergences, construction of Taylor series expansions of one-loop integrals, numerical evaluation with arbitrary precision arithmetic, manipulation of fermion chains, improved tensor algebraic routines, and much expanded documentation. Nature of problem: Analytic calculation of one-loop integrals in relativistic quantum field theory. Solution
Electroweak one-loop corrections for e+e- annihilation into t anti t including hard bremsstrahlung
International Nuclear Information System (INIS)
Fleischer, J.; Leike, A.; Riemann, T.; Werthenbach, A.
2003-01-01
We present the complete electroweak one-loop corrections to top-pair production at a linear e + e - collider in the continuum region. Besides weak and photonic virtual corrections, real hard bremsstrahlung with simple realistic kinematical cuts is included. For the bremsstrahlung we advocate a semi-analytical approach with a high numerical accuracy. The virtual corrections are parameterized through six independent form factors, suitable for Monte Carlo implementation. Alternatively, our numerical package Topfit, a stand-alone code, can be utilized for the calculation of both differential and integrated cross sections as well as forward-backward asymmetries. (orig.)
The one-loop contributions to c(t) electric dipole moment in the CP-violating BLMSSM
Energy Technology Data Exchange (ETDEWEB)
Zhao, Shu-Min; Feng, Tai-Fu; Yang, Zhong-Jun; Zhang, Hai-Bin; Dong, Xing-Xing [Hebei University, Department of Physics, Baoding (China); Guo, Tao [Hebei University of Geosciences, School of Mathematics and Science, Shijiazhuang (China)
2017-02-15
In the CP-violating supersymmetric extension of the standard model with local gauged baryon and lepton symmetries (BLMSSM), there are new CP-violating sources which can give new contributions to the quark electric dipole moment (EDM). Considering the CP-violating phases, we analyze the EDMs of the quarks c and t. We take into account the contributions from the one-loop diagrams. The numerical results are analyzed with some assumptions on the relevant parameter space. The numerical results for the c and t EDMs can reach large values. (orig.)
One loop corrections to the lightest Higgs mass in the minimal η model with a heavy Z'
International Nuclear Information System (INIS)
Comelli, D.
1992-06-01
We have evaluated the one loop correction to the bound on the lightest Higgs mass valid in the minimal, E 6 based, supersymmetric η model in the presence of a 'heavy' Z', M z' ≥1 TeV. The dominant contribution from the fermion sfermion sector increases the 108 GeV tree level value by an amount that depends on the top mass in a way that is largely reminescent of minimal SUSY models. For M t ≤150 GeV, Msub(t tilde)=1 TeV, the 'light' Higgs mass is always ≤130 GeV. (orig.)
International Nuclear Information System (INIS)
De Lya Insera, V.; Ferrer, Eh.; Shabad, A.E.
1986-01-01
Homogeneous and isotopic plasma of electrons and positrons is considered. Coefficients of covariant expansion of three-photon vertex in one-loop approximation of a technique of the Green temperature functions have been calculated and as a result amplitudes of different processes probability with the participation of three photons giving the data on the polarization state probability of incoming and outgoing photons in the splitting process. Sequences of all exact symmetries, which must be accomplished for vertex tensor, have been checked from calculational results. A case of charge-symmetrical plasma and a special case of photon collinearity have been considered
One-loop corrections to e+e− → e+e− in the weinberg model
Consoli, M.
1979-01-01
Radiative corrections to Bhabha scattering are calculated in the simplest example of non-Abelian gauge theories. A detailed analysis of the higher-order effects is presented and the total differential cross section including weak corrections is evaluated at different angles in an energy range up to
One-loop transition amplitudes in the D1D5 CFT
Energy Technology Data Exchange (ETDEWEB)
Carson, Zaq; Hampton, Shaun; Mathur, Samir D. [Department of Physics, The Ohio State University,191 West Woodruff Ave, Columbus, OH 43210 (United States)
2017-01-02
We consider the issue of thermalization in the D1D5 CFT. Thermalization is expected to correspond to the formation of a black hole in the dual gravity theory. We start from the orbifold point, where the theory is essentially free, and does not thermalize. In earlier work it was noted that there was no clear thermalization effect when the theory was deformed off the orbifold point to first order in the relevant twist perturbation. In this paper we consider the deformation to second order in the twist, where we do find effects that can cause thermalization of an initial perturbation. We consider a 1-loop process where two untwisted copies of the CFT are twisted to one copy and then again untwisted to two copies. We start with a single oscillator excitation on the initial CFT, and compute the effect of the two twists on this state. We find simple approximate expressions for the Bogoliubov coefficients and the behavior of the single oscillator excitation in the continuum limit, where the mode numbers involved are taken to be much larger than unity. We also prove a number of useful relationships valid for processes with an arbitrary number of twist insertions.
One-loop transition amplitudes in the D1D5 CFT
Carson, Zaq; Hampton, Shaun; Mathur, Samir D.
2017-01-01
We consider the issue of thermalization in the D1D5 CFT. Thermalization is expected to correspond to the formation of a black hole in the dual gravity theory. We start from the orbifold point, where the theory is essentially free, and does not thermalize. In earlier work it was noted that there was no clear thermalization effect when the theory was deformed off the orbifold point to first order in the relevant twist perturbation. In this paper we consider the deformation to second order in the twist, where we do find effects that can cause thermalization of an initial perturbation. We consider a 1-loop process where two untwisted copies of the CFT are twisted to one copy and then again untwisted to two copies. We start with a single oscillator excitation on the initial CFT, and compute the effect of the two twists on this state. We find simple approximate expressions for the Bogoliubov coefficients and the behavior of the single oscillator excitation in the continuum limit, where the mode numbers involved are taken to be much larger than unity. We also prove a number of useful relationships valid for processes with an arbitrary number of twist insertions.
International Nuclear Information System (INIS)
Somogyi, Gabor; Smith, Robert E.
2010-01-01
We generalize the renormalized perturbation theory (RPT) formalism of Crocce and Scoccimarro [M. Crocce and R. Scoccimarro, Phys. Rev. D 73, 063519 (2006)] to deal with multiple fluids in the Universe and here we present the complete calculations up to the one-loop level in the RPT. We apply this approach to the problem of following the nonlinear evolution of baryon and cold dark matter (CDM) perturbations, evolving from the distinct sets of initial conditions, from the high redshift post-recombination Universe right through to the present day. In current theoretical and numerical models of structure formation, it is standard practice to treat baryons and CDM as an effective single matter fluid--the so-called dark matter only modeling. In this approximation, one uses a weighed sum of late-time baryon and CDM transfer functions to set initial mass fluctuations. In this paper we explore whether this approach can be employed for high precision modeling of structure formation. We show that, even if we only follow the linear evolution, there is a large-scale scale-dependent bias between baryons and CDM for the currently favored WMAP5 ΛCDM model. This time evolving bias is significant (>1%) until the present day, when it is driven towards unity through gravitational relaxation processes. Using the RPT formalism we test this approximation in the nonlinear regime. We show that the nonlinear CDM power spectrum in the two-component fluid differs from that obtained from an effective mean-mass one-component fluid by ∼3% on scales of order k∼0.05h Mpc -1 at z=10, and by ∼0.5% at z=0. However, for the case of the nonlinear evolution of the baryons the situation is worse and we find that the power spectrum is suppressed, relative to the total matter, by ∼15% on scales k∼0.05h Mpc -1 at z=10, and by ∼3%-5% at z=0. Importantly, besides the suppression of the spectrum, the baryonic acoustic oscillation (BAO) features are amplified for baryon and slightly damped for CDM
Somogyi, Gábor; Smith, Robert E.
2010-01-01
We generalize the renormalized perturbation theory (RPT) formalism of Crocce and Scoccimarro [M. Crocce and R. Scoccimarro, Phys. Rev. DPRVDAQ1550-7998 73, 063519 (2006)10.1103/PhysRevD.73.063519] to deal with multiple fluids in the Universe and here we present the complete calculations up to the one-loop level in the RPT. We apply this approach to the problem of following the nonlinear evolution of baryon and cold dark matter (CDM) perturbations, evolving from the distinct sets of initial conditions, from the high redshift post-recombination Universe right through to the present day. In current theoretical and numerical models of structure formation, it is standard practice to treat baryons and CDM as an effective single matter fluid—the so-called dark matter only modeling. In this approximation, one uses a weighed sum of late-time baryon and CDM transfer functions to set initial mass fluctuations. In this paper we explore whether this approach can be employed for high precision modeling of structure formation. We show that, even if we only follow the linear evolution, there is a large-scale scale-dependent bias between baryons and CDM for the currently favored WMAP5 ΛCDM model. This time evolving bias is significant (>1%) until the present day, when it is driven towards unity through gravitational relaxation processes. Using the RPT formalism we test this approximation in the nonlinear regime. We show that the nonlinear CDM power spectrum in the two-component fluid differs from that obtained from an effective mean-mass one-component fluid by ˜3% on scales of order k˜0.05hMpc-1 at z=10, and by ˜0.5% at z=0. However, for the case of the nonlinear evolution of the baryons the situation is worse and we find that the power spectrum is suppressed, relative to the total matter, by ˜15% on scales k˜0.05hMpc-1 at z=10, and by ˜3%-5% at z=0. Importantly, besides the suppression of the spectrum, the baryonic acoustic oscillation (BAO) features are amplified for
Energy Technology Data Exchange (ETDEWEB)
Somogyi, Gabor [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Zurich Univ. (Switzerland). Inst. for Theoretical Physics; Smith, Robert E. [Zurich Univ. (Switzerland). Inst. for Theoretical Physics
2009-10-15
We generalize the ''renormalized'' perturbation theory (RPT) formalism of M. Crocce and R. Scoccimarro (2006) to deal with multiple fluids in the Universe and here we present the complete calculations up to the one-loop level in the RPT. We apply this approach to the problem of following the nonlinear evolution of baryon and cold dark matter (CDM) perturbations, evolving from the distinct sets of initial conditions, from the high redshift post-recombination Universe right through to the present day. In current theoretical and numerical models of structure formation, it is standard practice to treat baryons and CDM as an effective single matter fluid - the so called dark matter only modeling. In this approximation, one uses a weighed sum of late time baryon and CDM transfer functions to set initial mass fluctuations. In this paper we explore whether this approach can be employed for high precision modeling of structure formation. We show that, even if we only follow the linear evolution, there is a large-scale scale-dependent bias between baryons and CDM for the currently favored WMAP5 {lambda}CDM model. This time evolving bias is significant (> 1%) until the present day, when it is driven towards unity through gravitational relaxation processes. Using the RPT formalism we test this approximation in the non-linear regime. We show that the non-linear CDM power spectrum in the 2-component fluid differs from that obtained from an effective mean-mass 1-component fluid by {proportional_to} 3% on scales of order k {proportional_to} 0.05 h Mpc{sup -1} at z = 10, and by {proportional_to} 0.5% at z = 0. However, for the case of the non-linear evolution of the baryons the situation is worse and we find that the power spectrum is suppressed, relative to the total matter, by {proportional_to} 15% on scales k {proportional_to} 0.05 hMpc{sup -1} at z = 10, and by {proportional_to} 3 - 5% at z = 0. Importantly, besides the suppression of the spectrum, the
πK scattering in chiral perturbation theory to one loop
International Nuclear Information System (INIS)
Bernard, V.; Kaiser, N.; Strasbourg-1 Univ., 67; Meissner, U.G.
1991-01-01
We evaluate the πK scattering amplitude at next-to-leading order in the framework of chiral perturbation theory. All low-energy constants appearing in the effective lagrangian of the pseudoscalars have previously been determined. We calculate the scattering lengths of the S- and P-waves as well as the expansion parameters around the point ν triple bond (s-u)/4M K = t = 0 in the unphysical region. Furthermore, phase-shifts of the low partial ways are presented and compared to the data. In most cases, the chiral predictions are comparable to the trends set by the empirical information. For a precise comparison, however, more accurate experimental determinations of the πK scattering process at low and moderate energies would be necessary. We urge the experimenters to perform these. (orig.)
Ding, Mingnan; Lu, Bing-Sui; Xing, Xiangjun
2016-10-01
Self-consistent field theory (SCFT) is used to study the mean potential near a charged plate inside a m:-n electrolyte. A perturbation series is developed in terms of g=4πκb, where band1/κ are Bjerrum length and bare Debye length, respectively. To the zeroth order, we obtain the nonlinear Poisson-Boltzmann theory. For asymmetric electrolytes (m≠n), the first order (one-loop) correction to mean potential contains a secular term, which indicates the breakdown of the regular perturbation method. Using a renormalizaton group transformation, we remove the secular term and obtain a globally well-behaved one-loop approximation with a renormalized Debye length and a renormalized surface charge density. Furthermore, we find that if the counterions are multivalent, the surface charge density is renormalized substantially downwards and may undergo a change of sign, if the bare surface charge density is sufficiently large. Our results agrees with large MC simulation even when the density of electrolytes is relatively high.
On a family of (1+1)-dimensional scalar field theory models: Kinks, stability, one-loop mass shifts
Energy Technology Data Exchange (ETDEWEB)
Alonso-Izquierdo, A., E-mail: alonsoiz@usal.es [Departamento de Matematica Aplicada and IUFFyM, Universidad de Salamanca (Spain); Mateos Guilarte, J. [Departamento de Fisica Fundamental and IUFFyM, Universidad de Salamanca (Spain)
2012-09-15
In this paper we construct a one-parametric family of (1+1)-dimensional one-component scalar field theory models supporting kinks. Inspired by the sine-Gordon and {phi}{sup 4} models, we look at all possible extensions such that the kink second-order fluctuation operators are Schroedinger differential operators with Poeschl-Teller potential wells. In this situation, the associated spectral problem is solvable and therefore we shall succeed in analyzing the kink stability completely and in computing the one-loop quantum correction to the kink mass exactly. When the parameter is a natural number, the family becomes the hierarchy for which the potential wells are reflectionless, the two first levels of the hierarchy being the sine-Gordon and {phi}{sup 4} models. - Highlights: Black-Right-Pointing-Pointer We construct a family of scalar field theory models supporting kinks. Black-Right-Pointing-Pointer The second-order kink fluctuation operators involve Poeschl-Teller potential wells. Black-Right-Pointing-Pointer We compute the one-loop quantum correction to the kink mass with different methods.
One loop electro-weak radiative corrections in the standard model
International Nuclear Information System (INIS)
Kalyniak, P.; Sundaresan, M.K.
1987-01-01
This paper reports on the effect of radiative corrections in the standard model. A sensitive test of the three gauge boson vertices is expected to come from the work in LEPII in which the reaction e + e - → W + W - can occur. Two calculations of radiative corrections to the reaction e + e - → W + W - exist at present. The results of the calculations although very similar disagree with one another as to the actual magnitude of the correction. Some of the reasons for the disagreement are understood. However, due to the reasons mentioned below, another look must be taken at these lengthy calculations to resolve the differences between the two previous calculations. This is what is being done in the present work. There are a number of reasons why we must take another look at the calculation of the radiative corrections. The previous calculations were carried out before the UA1, UA2 data on W and Z bosons were obtained. Experimental groups require a computer program which can readily calculate the radiative corrections ab initio for various experimental conditions. The normalization of sin 2 θ w in the previous calculations was done in a way which is not convenient for use in the experimental work. It would be desirable to have the analytical expressions for the corrections available so that the renormalization scheme dependence of the corrections could be studied
One-loop radiative correction to the triple Higgs coupling in the Higgs singlet model
Directory of Open Access Journals (Sweden)
Shi-Ping He
2017-01-01
Full Text Available Though the 125 GeV Higgs boson is consistent with the standard model (SM prediction until now, the triple Higgs coupling can deviate from the SM value in the physics beyond the SM (BSM. In this paper, the radiative correction to the triple Higgs coupling is calculated in the minimal extension of the SM by adding a real gauge singlet scalar. In this model there are two scalars h and H and both of them are mixing states of the doublet and singlet. Provided that the mixing angle is set to be zero, namely the SM limit, h is the pure left-over of the doublet and its behavior is the same as that of the SM at the tree level. However the loop corrections can alter h-related couplings. In this SM limit case, the effect of the singlet H may show up in the h-related couplings, especially the triple h coupling. Our numerical results show that the deviation is sizable. For λΦS=1 (see text for the parameter definition, the deviation δhhh(1 can be 40%. For λΦS=1.5, the δhhh(1 can reach 140%. The sizable radiative correction is mainly caused by three reasons: the magnitude of the coupling λΦS, light mass of the additional scalar and the threshold enhancement. The radiative corrections for the hVV, hff couplings are from the counter-terms, which are the universal correction in this model and always at O(1%. The hZZ coupling, which can be precisely measured, may be a complementarity to the triple h coupling to search for the BSM. In the optimal case, the triple h coupling is very sensitive to the BSM physics, and this model can be tested at future high luminosity hadron colliders and electron–positron colliders.
Moduli effective action in warped brane-world compactifications
Energy Technology Data Exchange (ETDEWEB)
Garriga, Jaume E-mail: garriga@ifae.es; Pujolas, Oriol; Tanaka, Takahiro
2003-04-07
We consider a class of 5D brane-world solutions with a power-law warp factor a(y){proportional_to}y{sup q}, and bulk dilaton with profile phi{proportional_to}lny, where y is the proper distance in the extra dimension. This class includes the heterotic M-theory brane-world of [Phys. Rev. D 59 (1999) 086001, and] and the Randall-Sundrum (RS) model as a limiting case. In general, there are two moduli fields y{sub {+-}}, corresponding to the 'positions' of two branes (which live at the fixed points of an orbifold compactification). Classically, the moduli are massless, due to a scaling symmetry of the action. However, in the absence of supersymmetry, they develop an effective potential at one loop. Local terms proportional to K{sub {+-}}{sup 4}, where K{sub {+-}}=q/y{sub {+-}} is the local curvature scale at the location of the corresponding brane, are needed in order to remove the divergences in the effective potential. Such terms break the scaling symmetry and hence they may act as stabilizers for the moduli. When the branes are very close to each other, the effective potential induced by massless bulk fields behaves like V{approx}d{sup -4}, where d is the separation between branes. When the branes are widely separated, the potentials for each one of the moduli generically develop a 'Coleman-Weinberg'-type behaviour of the form a{sup 4}(y{sub {+-}})K{sub {+-}}{sup 4}ln(K{sub {+-}}/{mu}{sub {+-}}), where {mu}{sub {+-}} are renormalization scales. In the RS case, the bulk geometry is AdS and K{sub {+-}} are equal to a constant, independent of the position of the branes, so these terms do not contribute to the mass of the moduli. However, for generic warp factor, they provide a simple stabilization mechanism. For q > or approx. 10, the observed hierarchy can be naturally generated by this potential, giving the lightest modulus a mass of order m{sub -} < or approx. TeV.
Effective actions for F-theory compactifications and tensor theories
International Nuclear Information System (INIS)
Bonetti, Federico
2014-01-01
In this thesis we study the low-energy effective dynamics emerging from a class of F-theory compactifications in four and six dimensions. We also investigate six-dimensional supersymmetric quantum field theories with self-dual tensors, motivated by the problem of describing the long-wavelength regime of a stack of M5-branes in M-theory. These setups share interesting common features. They both constitute examples of intrinsically non-perturbative physics. On the one hand, in the context of F-theory the non-perturbative character is encoded in the geometric formulation of this class of string vacua, which allows the complexified string coupling to vary in space. On the other hand, the dynamics of a stack of multiple M5-branes flows in the infrared to a novel kind of superconformal field theories in six dimensions - commonly referred to as (2,0) theories - that are expected to possess no perturbative weakly coupled regime and have resisted a complete understanding so far. In particular, no Lagrangian description is known for these models. The strategy we employ to address these two problems is also analogous. A recurring Leitmotif of our work is a transdimensional treatment of the system under examination: in order to extract information about dynamics in d dimensions we consider a (d-1)-dimensional setup. As far as F-theory compactifications are concerned, this is a consequence of the duality between M-theory and F-theory, which constitutes our main tool in the derivation of the effective action of F-theory compactifications. We apply it to six-dimensional F-theory vacua, obtained by taking the internal space to be an elliptically fibered Calabi-Yau threefold, but we also employ it to explore a novel kind of F-theory constructions in four dimensions based on manifolds with Spin(7) holonomy. With reference to six-dimensional (2,0) theories, the transdimensional character of our approach relies in the idea of studying these theories in five dimensions. Indeed, we
International Nuclear Information System (INIS)
Sun Yi; Chang Haoran
2012-01-01
By further examining the symmetry of external momenta and masses in Feynman integrals, we fulfilled the method proposed by Battistel and Dallabona, and showed that recursion relations in this method can be applied to simplify Feynman integrals directly. (authors)
Action-based effects on music perception.
Maes, Pieter-Jan; Leman, Marc; Palmer, Caroline; Wanderley, Marcelo M
2014-01-03
The classical, disembodied approach to music cognition conceptualizes action and perception as separate, peripheral processes. In contrast, embodied accounts of music cognition emphasize the central role of the close coupling of action and perception. It is a commonly established fact that perception spurs action tendencies. We present a theoretical framework that captures the ways in which the human motor system and its actions can reciprocally influence the perception of music. The cornerstone of this framework is the common coding theory, postulating a representational overlap in the brain between the planning, the execution, and the perception of movement. The integration of action and perception in so-called internal models is explained as a result of associative learning processes. Characteristic of internal models is that they allow intended or perceived sensory states to be transferred into corresponding motor commands (inverse modeling), and vice versa, to predict the sensory outcomes of planned actions (forward modeling). Embodied accounts typically refer to inverse modeling to explain action effects on music perception (Leman, 2007). We extend this account by pinpointing forward modeling as an alternative mechanism by which action can modulate perception. We provide an extensive overview of recent empirical evidence in support of this idea. Additionally, we demonstrate that motor dysfunctions can cause perceptual disabilities, supporting the main idea of the paper that the human motor system plays a functional role in auditory perception. The finding that music perception is shaped by the human motor system and its actions suggests that the musical mind is highly embodied. However, we advocate for a more radical approach to embodied (music) cognition in the sense that it needs to be considered as a dynamical process, in which aspects of action, perception, introspection, and social interaction are of crucial importance.
Action-based effects on music perception
Maes, Pieter-Jan; Leman, Marc; Palmer, Caroline; Wanderley, Marcelo M.
2013-01-01
The classical, disembodied approach to music cognition conceptualizes action and perception as separate, peripheral processes. In contrast, embodied accounts of music cognition emphasize the central role of the close coupling of action and perception. It is a commonly established fact that perception spurs action tendencies. We present a theoretical framework that captures the ways in which the human motor system and its actions can reciprocally influence the perception of music. The cornerstone of this framework is the common coding theory, postulating a representational overlap in the brain between the planning, the execution, and the perception of movement. The integration of action and perception in so-called internal models is explained as a result of associative learning processes. Characteristic of internal models is that they allow intended or perceived sensory states to be transferred into corresponding motor commands (inverse modeling), and vice versa, to predict the sensory outcomes of planned actions (forward modeling). Embodied accounts typically refer to inverse modeling to explain action effects on music perception (Leman, 2007). We extend this account by pinpointing forward modeling as an alternative mechanism by which action can modulate perception. We provide an extensive overview of recent empirical evidence in support of this idea. Additionally, we demonstrate that motor dysfunctions can cause perceptual disabilities, supporting the main idea of the paper that the human motor system plays a functional role in auditory perception. The finding that music perception is shaped by the human motor system and its actions suggests that the musical mind is highly embodied. However, we advocate for a more radical approach to embodied (music) cognition in the sense that it needs to be considered as a dynamical process, in which aspects of action, perception, introspection, and social interaction are of crucial importance. PMID:24454299
Action-based effects on music perception
Directory of Open Access Journals (Sweden)
Pieter-Jan eMaes
2014-01-01
Full Text Available The classical, disembodied approach to music cognition conceptualizes action and perception as separate, peripheral phenomena. In contrast, embodied accounts to music cognition emphasize the central role of the close coupling of action and perception. It is a commonly established fact that perception spurs action tendencies. We present a theoretical framework capturing the ways that the human motor system, and the actions it produces, can reciprocally influence the perception of music. The cornerstone of this framework is the common coding theory postulating a representational overlap in the brain between the planning, the execution, and the perception of movement. The integration of action and perception in so-called internal models is explained as a result of associative learning processes. Characteristic of internal models is that they allow intended or perceived sensory states to be transferred into corresponding motor commands (inverse modelling, and vice versa, to predict the sensory outcomes of planned actions (forward modelling. Embodied accounts typically adhere to inverse modelling to explain action effects on music perception (Leman, 2007. We extent this account by pinpointing forward modelling as an alternative mechanism by which action can modulate perception. We provide an extensive overview of recent empirical evidence in support of this idea. Additionally, we demonstrate that motor dysfunctions can cause perceptual disabilities, supporting the main idea of the paper that the human motor system plays a functional role in auditory perception. The finding that music perception is shaped by the human motor system, and the action it produces, suggests that the musical mind is highly embodied. However, we advocate for a more radical approach to embodied (music cognition in the sense that it needs to be considered as a dynamic process, in which aspects of action, perception, introspection, and social interaction are of crucial
One-loop Wilson loops and the particle-interface potential in AdS/dCFT
Directory of Open Access Journals (Sweden)
Marius de Leeuw
2017-05-01
Full Text Available We initiate the calculation of quantum corrections to Wilson loops in a class of four-dimensional defect conformal field theories with vacuum expectation values based on N=4 super Yang–Mills theory. Concretely, we consider an infinite straight Wilson line, obtaining explicit results for the one-loop correction to its expectation value in the large-N limit. This allows us to extract the particle-interface potential of the theory. In a further double-scaling limit, we compare our results to those of a previous calculation in the dual string-theory set-up consisting of a D5-D3 probe-brane system with flux, and we find perfect agreement.
Energy Technology Data Exchange (ETDEWEB)
Liu, Zhen, E-mail: liu-zhen@sjtu.edu.cn; Gu, Pei-Hong, E-mail: peihong.gu@sjtu.edu.cn
2017-02-15
We extend some two Higgs doublet models, where the Yukawa couplings for the charged fermion mass generation only involve one Higgs doublet, by two singlet scalars respectively carrying a singly electric charge and a doubly electric charge. The doublet and singlet scalars together can mediate a two-loop diagram to generate a tiny Majorana mass matrix of the standard model neutrinos. Remarkably, the structure of the neutrino mass matrix is fully determined by the symmetric Yukawa couplings of the doubly charged scalar to the right-handed leptons. Meanwhile, a one-loop induced neutrinoless double beta decay can arrive at a testable level even if the electron neutrino has an extremely small Majorana mass. We also study other experimental constraints and implications including some rare processes and Higgs phenomenology.
Directory of Open Access Journals (Sweden)
Zhen Liu
2017-02-01
Full Text Available We extend some two Higgs doublet models, where the Yukawa couplings for the charged fermion mass generation only involve one Higgs doublet, by two singlet scalars respectively carrying a singly electric charge and a doubly electric charge. The doublet and singlet scalars together can mediate a two-loop diagram to generate a tiny Majorana mass matrix of the standard model neutrinos. Remarkably, the structure of the neutrino mass matrix is fully determined by the symmetric Yukawa couplings of the doubly charged scalar to the right-handed leptons. Meanwhile, a one-loop induced neutrinoless double beta decay can arrive at a testable level even if the electron neutrino has an extremely small Majorana mass. We also study other experimental constraints and implications including some rare processes and Higgs phenomenology.
Directory of Open Access Journals (Sweden)
Shinya Kanemura
2015-07-01
Full Text Available We calculate radiative corrections to a full set of coupling constants for the 125 GeV Higgs boson at the one-loop level in two Higgs doublet models with four types of Yukawa interaction under the softly-broken discrete Z2 symmetry. The renormalization calculations are performed in the on-shell scheme, in which the gauge dependence in the mixing parameter which appears in the previous calculation is consistently avoided. We first show the details of our renormalization scheme, and present the complete set of the analytic formulae of the renormalized couplings. We then numerically demonstrate how the inner parameters of the model can be extracted by the future precision measurements of these couplings at the high luminosity LHC and the International Linear Collider.
The one-loop six-dimensional hexagon integral and its relation to MHV amplitudes in N=4 SYM
Dixon, Lance J.; Henn, Johannes M.
2011-01-01
We provide an analytic formula for the (rescaled) one-loop scalar hexagon integral $\\tilde\\Phi_6$ with all external legs massless, in terms of classical polylogarithms. We show that this integral is closely connected to two integrals appearing in one- and two-loop amplitudes in planar $\\\\mathcal{N}=4$ super-Yang-Mills theory, $\\Omega^{(1)}$ and $\\Omega^{(2)}$. The derivative of $\\Omega^{(2)}$ with respect to one of the conformal invariants yields $\\tilde\\Phi_6$, while another first-order differential operator applied to $\\tilde\\Phi_6$ yields $\\Omega^{(1)}$. We also introduce some kinematic variables that rationalize the arguments of the polylogarithms, making it easy to verify the latter differential equation. We also give a further example of a six-dimensional integral relevant for amplitudes in $\\\\mathcal{N}=4$ super-Yang-Mills.
Ventura, Marcelo; Endriss, Daniela
2010-01-01
To evaluate the postoperative results of congenital lens subluxation corrected by a new technique. Retrospective chart review of 21 eyes of 13 patients with no traumatic lens subluxation who underwent surgery in Altino Ventura Foundation from April, 1999 to April, 2004. The mean age was 8.7 +/- 5.4 years old, and the mean follow-up period was 21.5 +/- 19.3 months. Patients underwent phacoaspiration, endocapsular ring and intraocular lens (IOL) implantation. The implanted IOL had one loop haptic excised and was supported above the ring, inside the capsular bag promoting intraocular lens centralization. Visual acuity improvement was observed in all cases. There was a significant reduction of the spherical equivalent and spherical component comparing the pre and postoperative refraction (psubluxation surgical treatment, promoting lens centralization and postoperative visual acuity improvement.
The average action for scalar fields near phase transitions
International Nuclear Information System (INIS)
Wetterich, C.
1991-08-01
We compute the average action for fields in two, three and four dimensions, including the effects of wave function renormalization. A study of the one loop evolution equations for the scale dependence of the average action gives a unified picture of the qualitatively different behaviour in various dimensions for discrete as well as abelian and nonabelian continuous symmetry. The different phases and the phase transitions can be infered from the evolution equation. (orig.)
Full one-loop QCD and electroweak corrections to sfermion pair production in γγ collisions
International Nuclear Information System (INIS)
Xing Lirong; Zhang Renyou; Jiang Yi; Han Liang; Li Gang; Ma Wengan
2005-01-01
We have calculated the full one-loop electroweak (EW) and QCD corrections to the third generation scalar-fermion pair production processes e + e - →γγ→f i -tildef i -tilde(f=t,b,τ) at an electron-positron linear collider(LC) in the minimal supersymmetric standard model (MSSM). We analyze the dependence of the radiative corrections on the parameters such as the colliding energy √(s-circumflex) and the SUSY fundamental parameters A f , tanβ, μ, M SUSY and so forth. The numerical results show that the EW corrections to the squark-, stau-pair production processes and QCD corrections to the squark-pair production processes give substantial contributions in some parameter space. The EW relative corrections to squark-pair production processes can be comparable with QCD corrections at high energies. Therefore, these EW and QCD corrections cannot be neglected in precise measurement of sfermion pair productions via γγ collision at future linear colliders
Kazantsev, A. E.; Skoptsov, M. B.; Stepanyantz, K. V.
2017-11-01
We consider the general 𝒩 = 1 supersymmetric gauge theory with matter, regularized by higher covariant derivatives without breaking the BRST invariance, in the massless limit. In the ξ-gauge we obtain the (unrenormalized) expression for the two-point Green function of the quantum gauge superfield in the one-loop approximation as a sum of integrals over the loop momentum. The result is presented as a sum of three parts: the first one corresponds to the pure supersymmetric Yang-Mills theory in the Feynman gauge, the second one contains all gauge-dependent terms, and the third one is the contribution of diagrams with a matter loop. For the Feynman gauge and a special choice of the higher derivative regulator in the gauge fixing term, we analytically calculate these integrals in the limit k → 0. In particular, in addition to the leading logarithmically divergent terms, which are determined by integrals of double total derivatives, we also find the finite constants.
Associated production of a quarkonium and a Z boson at one loop in a quark-hadron-duality approach
Lansberg, Jean-Philippe
2016-01-01
In view of the large discrepancy about the associated production of a prompt $J/\\psi$ and a $Z$ boson between the ATLAS data at $\\sqrt{s}=8$ TeV and theoretical predictions for Single Parton Scattering (SPS) contributions, we perform an evaluation of the corresponding cross section at one loop accuracy (Next-to-Leading Order, NLO) in a quark-hadron-duality approach, also known as the Colour-Evaporation Model (CEM). This work is motivated by (i) the extremely disparate predictions based on the existing NRQCD fits conjugated with the absence of a full NLO NRQCD computation and (ii) the fact that we believe that such an evaluation provides a likely upper limit of the SPS cross section. In addition to these theory improvements, we argue that the ATLAS estimation of the Double Parton Scattering (DPS) yield may be underestimated by a factor as large as 3 which then reduces the size of the SPS yield extracted from the ATLAS data. Our NLO SPS evaluation also allows us to set an upper limit on $\\sigma_{\\rm eff}$ drivi...
Courant algebroid connections and string effective actions
Jurčo, B.
2017-01-01
Courant algebroids are a natural generalization of quadratic Lie algebras, appearing in various contexts in mathematical physics. A connection on a Courant algebroid gives an analogue of a covariant derivative compatible with a given fiber-wise metric. Imposing further conditions resembling standard Levi-Civita connections, one obtains a class of connections whose curvature tensor in certain cases gives a new geometrical description of equations of motion of low energy effective action of str...
The effective action for chiral fermions
International Nuclear Information System (INIS)
Alvarez-Gaume, L.
1985-01-01
This paper reports on recent work which given an exact characterization of the imaginary part of the effective action for chiral fermions in 2n dimensions in terms of the spectral asymmetry of a suitable (2n+1)-dimensional operator. In order to keep the discussion as simple as possible, the author concentrates on four dimensional fermions with arbitrary external gauge fields. This approach can be extended without difficulty to higher dimensions and also to include external gravitational fields
Exploring soft constraints on effective actions
Energy Technology Data Exchange (ETDEWEB)
Bianchi, Massimo; Guerrieri, Andrea L. [Dipartimento di Fisica, Università di Roma “Tor Vergata”,I.N.F.N. Sezione di Roma “Tor Vergata”,Via della Ricerca Scientifica, Roma, 00133 (Italy); Huang, Yu-tin; Lee, Chao-Jung [Department of Physics and Astronomy, National Taiwan University,No. 1 Roosevelt Road Sec. 4, Taipei, Taiwan (China); Wen, Congkao [Dipartimento di Fisica, Università di Roma “Tor Vergata”,I.N.F.N. Sezione di Roma “Tor Vergata”,Via della Ricerca Scientifica, Roma, 00133 (Italy)
2016-10-10
We study effective actions for simultaneous breaking of space-time and internal symmetries. Novel features arise due to the mixing of Goldstone modes under the broken symmetries which, in contrast to the usual Adler’s zero, leads to non-vanishing soft limits. Such scenarios are common for spontaneously broken SCFT’s. We explicitly test these soft theorems for N=4 sYM in the Coulomb branch both perturbatively and non-perturbatively. We explore the soft constraints systematically utilizing recursion relations. In the pure dilaton sector of a general CFT, we show that all amplitudes up to order s{sup n}∼∂{sup 2n} are completely determined in terms of the k-point amplitudes at order s{sup k} with k≤n. Terms with at most one derivative acting on each dilaton insertion are completely fixed and coincide with those appearing in the conformal DBI, i.e. DBI in AdS. With maximal supersymmetry, the effective actions are further constrained, leading to new non-renormalization theorems. In particular, the effective action is fixed up to eight derivatives in terms of just one unknown four-point coefficient and one more coefficient for ten-derivative terms. Finally, we also study the interplay between scale and conformal invariance in this context.
Influence of verbal instructions on effect-based action control.
Eder, Andreas B; Dignath, David
2017-03-01
According to ideomotor theory, people use bidirectional associations between movements and their effects for action selection and initiation. Our experiments examined how verbal instructions of action effects influence response selection without prior experience of action effects in a separate acquisition phase. Instructions for different groups of participants specified whether they should ignore, attend, learn, or intentionally produce acoustic effects produced by button presses. Results showed that explicit instructions of action-effect relations trigger effect-congruent action tendencies in the first trials following the instruction; in contrast, no evidence for effect-based action control was observed in these trials when instructions were to ignore or to attend to the action effects. These findings show that action-effect knowledge acquired through verbal instruction and direct experience is similarly effective for effect-based action control as long as the relation between the movement and the effect is clearly spelled out in the instruction.
International Nuclear Information System (INIS)
Philippov, Yu. P.
2009-01-01
Within the minimal supersymmetric standard model, the amplitudes and total cross sections for the processes e + e - → hh, e + e - → hH, e + e - → HH, and e + e - → AA are calculated in the first order of perturbation theory with allowance for a complete set of one-loop diagrams in the m e → 0 approximation. Analytic expressions are obtained for the quantities under consideration; numerical results are presented in a graphical form. It is shown that the cross section for the process e + e - → hh is larger than those for the other processes (and is on the same order of magnitude as the cross section for the corresponding processes in the Standard Model). In the case of the collision energy equal to √s = 500 GeV, an integrated luminosity in the region ∫ L ≥ 500 fb -1 , and a longitudinal polarization of the e + e- beams used, 520, 320, and 300 production events are possible in the processes e + e - → hh (at M h = 115 GeV), e + e - → HH, and e + e - → AA (at M H,A = 120 GeV), respectively. Even at M H,A ∼ 500 GeV and √s = 1.5 TeV, not less than 200 events for each of the processes can be accumulated. The cross section for the process e + e - → hH is small (about 10 -2 fb), which complicates the detection of the sought signal significantly.
A non-perturbative study of 4d U(1) non-commutative gauge theory - the fate of one-loop instability
International Nuclear Information System (INIS)
Bietenholz, Wolfgang; Nishimura, Jun; Susaki, Yoshiaki; Volkholz, Jan
2006-01-01
Recent perturbative studies show that in 4d non-commutative spaces, the trivial (classically stable) vacuum of gauge theories becomes unstable at the quantum level, unless one introduces sufficiently many fermionic degrees of freedom. This is due to a negative IR-singular term in the one-loop effective potential, which appears as a result of the UV/IR mixing. We study such a system non-perturbatively in the case of pure U(1) gauge theory in four dimensions, where two directions are non-commutative. Monte Carlo simulations are performed after mapping the regularized theory onto a U(N) lattice gauge theory in d = 2. At intermediate coupling strength, we find a phase in which open Wilson lines acquire non-zero vacuum expectation values, which implies the spontaneous breakdown of translational invariance. In this phase, various physical quantities obey clear scaling behaviors in the continuum limit with a fixed non-commutativity parameter θ, which provides evidence for a possible continuum theory. The extent of the dynamically generated space in the non-commutative directions becomes finite in the above limit, and its dependence on θ is evaluated explicitly. We also study the dispersion relation. In the weak coupling symmetric phase, it involves a negative IR-singular term, which is responsible for the observed phase transition. In the broken phase, it reveals the existence of the Nambu-Goldstone mode associated with the spontaneous symmetry breaking
A non-perturbative study of 4d U(1) non-commutative gauge theory — the fate of one-loop instability
Bietenholz, Wolfgang; Nishimura, Jun; Susaki, Yoshiaki; Volkholz, Jan
2006-10-01
Recent perturbative studies show that in 4d non-commutative spaces, the trivial (classically stable) vacuum of gauge theories becomes unstable at the quantum level, unless one introduces sufficiently many fermionic degrees of freedom. This is due to a negative IR-singular term in the one-loop effective potential, which appears as a result of the UV/IR mixing. We study such a system non-perturbatively in the case of pure U(1) gauge theory in four dimensions, where two directions are non-commutative. Monte Carlo simulations are performed after mapping the regularized theory onto a U(N) lattice gauge theory in d = 2. At intermediate coupling strength, we find a phase in which open Wilson lines acquire non-zero vacuum expectation values, which implies the spontaneous breakdown of translational invariance. In this phase, various physical quantities obey clear scaling behaviors in the continuum limit with a fixed non-commutativity parameter θ, which provides evidence for a possible continuum theory. The extent of the dynamically generated space in the non-commutative directions becomes finite in the above limit, and its dependence on θ is evaluated explicitly. We also study the dispersion relation. In the weak coupling symmetric phase, it involves a negative IR-singular term, which is responsible for the observed phase transition. In the broken phase, it reveals the existence of the Nambu-Goldstone mode associated with the spontaneous symmetry breaking.
QCD bosonization and the meson effective action
International Nuclear Information System (INIS)
Praschifka, J.; Roberts, C.D.; Cahill, R.T.
1987-01-01
A bosonization of quantum chromodynamics (QCD) is employed to derive a meson effective action, thus providing a direct link between QCD and meson phenomenology. As an example of this approach expressions are obtained for the meson parameters associated with the analysis of ω→3π decay. The bosonization also directly motivates a divergence-free, global color-symmetry model for mesons, which is seen to be a generalization of various phenomenological models. Good estimates are obtained for the values of several of the meson parameters
Effective action calculation in lattice QCD
International Nuclear Information System (INIS)
Hoek, J.
1983-01-01
A method (called the effective action method) devised to make analytic calculations in Quantum Chromodynamics in the region of strong coupling is presented. First, the author deals with developing the calculation of a strong coupling expansion of the generating functional for gauge systems on a lattice with arbitrary sources. An accompanying manual describes the implementation of this calculation on a computer. The next step consists of substituting the expressions for the one-link free energies for a specific gauge group in the result of the previous calculation. This process of substitution, together with the replacement of the sources by a bilinear combination of fermion fields, is described for the group SU(3). More details on the implementation of the substitution scheme on a computer can be found in the accompanying manual. From the effective action thus obtained in terms of meson fields and baryon fields the Green functions of the theory can be derived. As an illustrative application the effective potential determining the vacuum expectation value of the meson field is calculated. (Auth.)
Indirect effects in dual radiation action
International Nuclear Information System (INIS)
Zaider, M.; Rossi, H.H.
1988-01-01
The basic aim in this paper is to establish the link between indirect effects of radiation action and the spatial distribution of radicals at the time of energy deposition as well as throughout subsequent diffusion and interaction. The fact that radicals diffuse for a finite distance before damaging a biomolecule has dramatic effects on their subsequent probability to result in lesions. Thus at very low DMSO concentrations, where p = 0.5, one expects - all other things being equal - some 75% of the lesions to result from indirect or semidirect lesions. The number calculated here is lower (15%), a direct result of the fact that such lesions involve proximity functions modulated by diffusion. At higher DMSO concentrations this percentage becomes progressively smaller, as expected. It appears thus that for low-LET radiation, the relative amount of indirect damage in single tracks (also termed intratrack or single events) action is very small. By contrast, intertrack (or two-event) contributions will have the ratio between direct and (indirect + semidirect) contributions given by p 2 /(1-p 2 ). The reason for this is that sublesions from different tracks are uniformly distributed throughout the cell nucleus; their probability of interaction should not depend on any previous diffusional processes. For the example given above (p = 0.5) they do expect 65% of intertrack (two-hit) lesions to have resulted from indirect or semidirect mechanisms. This contrast between the almost exclusively direct character of intratrack lesions and the dominant role of indirect action in intertrack lesions produced by low-LET radiation is an important conclusion of this study
Inflationary magnetogenesis and non-local actions: the conformal anomaly
Energy Technology Data Exchange (ETDEWEB)
El-Menoufi, Basem Kamal, E-mail: bmahmoud@physics.umass.edu [Department of Physics, University of Massachusetts Amherst, MA 01003 (United States)
2016-02-01
We discuss the possibility of successful magnetogenesis during inflation by employing the one-loop effective action of massless QED. The action is strictly non-local and results from the long distance fluctuations of massless charged particles present at the inflationary scale. Most importantly, it encodes the conformal anomaly of QED which is crucial to avoid the vacuum preservation in classical electromagnetism. In particular, we find a blue spectrum for the magnetic field with spectral index n{sub B} ≅ 2 − α{sub e} where α{sub e} depends on both the number of e-folds during inflation as well as the coefficient of the one-loop beta function. In particular, the sign of the beta function has important bearing on the final result. A low reheating temperature is required for the present day magnetic field to be consistent with the lower bound inferred on the field in the intergalactic medium.
Effects of BDNF polymorphisms on antidepressant action.
Tsai, Shih-Jen; Hong, Chen-Jee; Liou, Ying-Jay
2010-12-01
Evidence suggests that the down-regulation of the signaling pathway involving brain-derived neurotrophic factor (BDNF), a molecular element known to regulate neuronal plasticity and survival, plays an important role in the pathogenesis of major depression. The restoration of BDNF activity induced by antidepressant treatment has been implicated in the antidepressant therapeutic mechanism. Because there is variability among patients with major depressive disorder in terms of response to antidepressant treatment and since genetic factors may contribute to this inter-individual variability in antidepressant response, pharmacogenetic studies have tested the associations between genetic polymorphisms in candidate genes related to antidepressant therapeutic action. In human BDNF gene, there is a common functional polymorphism (Val66Met) in the pro-region of BDNF, which affects the intracellular trafficking of proBDNF. Because of the potentially important role of BDNF in the antidepressant mechanism, many pharmacogenetic studies have tested the association between this polymorphism and the antidepressant therapeutic response, but they have produced inconsistent results. A recent meta-analysis of eight studies, which included data from 1,115 subjects, suggested that the Val/Met carriers have increased antidepressant response in comparison to Val/Val homozygotes, particularly in the Asian population. The positive molecular heterosis effect (subjects heterozygous for a specific genetic polymorphism show a significantly greater effect) is compatible with animal studies showing that, although BDNF exerts an antidepressant effect, too much BDNF may have a detrimental effect on mood. Several recommendations are proposed for future antidepressant pharmacogenetic studies of BDNF, including the consideration of multiple polymorphisms and a haplotype approach, gene-gene interaction, a single antidepressant regimen, controlling for age and gender interactions, and pharmacogenetic
Wong's equations and the small x effective action in QCD
International Nuclear Information System (INIS)
Jalilian-Marian, Jamal; Jeon, Sangyong; Venugopalan, Raju
2001-01-01
We propose a new form for the small x effective action in QCD. This form of the effective action is motivated by Wong's equations for classical, colored particles in non-Abelian background fields. We show that the BFKL equation, which sums leading logarithms in x, is efficiently reproduced with this form of the action. We argue that this form of the action may be particularly useful in computing next-to-leading-order results in QCD at small x
Wong's equations and the small x effective action in QCD
International Nuclear Information System (INIS)
Jalilian-Marian, Jamal; Jeon, Sangyong; Venugopalan, Raju
2000-01-01
We propose a new form for the small x effective action in QCD. This form of the effective action is motivated by Wong's equations for classical, colored particles in non-Abelian background fields. We show that the BFKL equation, which sums leading logarithms in x, is efficiently reproduced with this form of the action. We argue that this form of the action may be particularly useful in computing next-to-leading-order results in QCD at small x
Energy Technology Data Exchange (ETDEWEB)
Boussarie, R. [Laboratoire de Physique Théorique, UMR 8627, CNRS, University Paris-Sud, CNRS,Université Paris-Saclay,91405, Orsay (France); Grabovsky, A.V. [Budker Institute of Nuclear Physics,11, Lavrenteva avenue, 630090, Novosibirsk (Russian Federation); Novosibirsk State University,630090, 2, Pirogova street, Novosibirsk (Russian Federation); Department of Physics, University of Minnesota,Duluth, Minnesota, 55812 (United States); Szymanowski, L. [National Centre for Nuclear Research (NCBJ),Warsaw (Poland); Wallon, S. [Laboratoire de Physique Théorique, UMR 8627, CNRS, University Paris-Sud, CNRS,Université Paris-Saclay,91405, Orsay (France); UPMC University Paris 06, faculté de physique,4 place Jussieu, 75252 Paris Cedex 05 (France)
2016-11-24
We present the calculation of the impact factor for the γ{sup (∗)}→qq̄ transition with one loop accuracy in arbitrary kinematics. The calculation was done within Balitsky’s high energy operator expansion. Together with our previous result for the γ{sup (∗)}→qq̄g Born impact factor it allows one to derive cross sections for 2- (one loop) and 3-jet (Born) difractive electroproduction. We write such cross sections for the 2 and 3 jet exclusive diffractive electroproduction off a proton in terms of hadronic matrix elements of Wilson lines. For the 2-jet cross section we demonstrate the cancellation of infrared, collinear and rapidity singularities. Our result can be directly exploited to describe the recently analyzed data on exclusive dijet production at HERA and used for the study of jet photoproduction in ultraperipheral proton or nuclear scattering.
International Nuclear Information System (INIS)
Boussarie, R.; Grabovsky, A.V.; Szymanowski, L.; Wallon, S.
2016-01-01
We present the calculation of the impact factor for the γ (∗) →qq̄ transition with one loop accuracy in arbitrary kinematics. The calculation was done within Balitsky’s high energy operator expansion. Together with our previous result for the γ (∗) →qq̄g Born impact factor it allows one to derive cross sections for 2- (one loop) and 3-jet (Born) difractive electroproduction. We write such cross sections for the 2 and 3 jet exclusive diffractive electroproduction off a proton in terms of hadronic matrix elements of Wilson lines. For the 2-jet cross section we demonstrate the cancellation of infrared, collinear and rapidity singularities. Our result can be directly exploited to describe the recently analyzed data on exclusive dijet production at HERA and used for the study of jet photoproduction in ultraperipheral proton or nuclear scattering.
Dark matter, muon g -2 , electric dipole moments, and Z →ℓi+ℓj- in a one-loop induced neutrino model
Chiang, Cheng-Wei; Okada, Hiroshi; Senaha, Eibun
2017-07-01
We study a simple one-loop induced neutrino mass model that contains both bosonic and fermionic dark matter candidates and has the capacity to explain the muon anomalous magnetic moment anomaly. We perform a comprehensive analysis by taking into account the relevant constraints of charged lepton flavor violation, electric dipole moments, and neutrino oscillation data. We examine the constraints from lepton flavor-changing Z boson decays at the one-loop level, particularly when the involved couplings contribute to the muon g -2 . It is found that BR (Z →μ τ )≃(10-7- 10-6) while BR (τ →μ γ )≲10-11 in the fermionic dark matter scenario. The former can be probed by the precision measurement of the Z boson at future lepton colliders.
One-loop corrections of orders (Zα)6m1/m2 and (Zα)7 to the fine structure of muonium
International Nuclear Information System (INIS)
Martynenko, A.P.; Faustov, R.N.
2003-01-01
Corrections of orders (Zα) 6 m 1 /m 2 and (Zα) 7 from one-loop two-photon amplitudes to the energy spectra of hydrogen-like atoms are calculated by expanding the relevant integrand in a Taylor series. A method for averaging the resulting quasipotential in the d-dimensional coordinate representation is formulated. Numerical values are obtained for the corresponding contributions to the fine structure of the muonium, hydrogen, and positronium atoms
Energy Technology Data Exchange (ETDEWEB)
Koerner, J.G. [Mainz Univ. (Germany). Inst. fuer Physik; Merebashvili, Z. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Rogal, M. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2008-02-15
We calculate the NNLO O({alpha}{sup 4}{sub s}) one-loop squared corrections to the production of heavy quark pairs in quark-antiquark annihilations. These are part of the NNLO O({alpha}{sup 4}{sub s}) radiative QCD corrections to this process. Our results, with the full mass dependence retained, are presented in a closed and very compact form, in the dimensional regularization scheme. We find very intriguing factorization properties for the finite part of the amplitudes. (orig.)
International Nuclear Information System (INIS)
Koerner, J.G.
2008-02-01
We calculate the NNLO O(α 4 s ) one-loop squared corrections to the production of heavy quark pairs in quark-antiquark annihilations. These are part of the NNLO O(α 4 s ) radiative QCD corrections to this process. Our results, with the full mass dependence retained, are presented in a closed and very compact form, in the dimensional regularization scheme. We find very intriguing factorization properties for the finite part of the amplitudes. (orig.)
Effects of social intention on movement kinematics in cooperative actions
Directory of Open Access Journals (Sweden)
Francois eQuesque
2013-10-01
Full Text Available Optimal control models of biological movements are used to account for those internal variables that constrain voluntary goal-directed actions. They however do not take into account external environmental constraints as those associated to social intention. We investigated here the effects of the social context on kinematic characteristics of sequential actions consisting in placing an object on an initial pad (preparatory action before reaching and grasping as fast as possible the object to move it to another location (main action. Reach-to-grasp actions were performed either in an isolated condition or in the presence of a partner (audience effect, located in the near or far space (effect of shared reachable space, and who could intervene on the object in a systematic fashion (effect of social intention effect or not (effect of social uncertainty. Results showed an absence of audience effect but nevertheless an influence of the social context both on the main and the preparatory actions. In particular, a localized effect of shared reachable space was observed on the main action, which was smoother when performed within the reachable space of the partner. Furthermore, a global effect of social uncertainty was observed on both actions with faster and jerkier movements. Finally, social intention affected the preparatory action with higher wrist displacements and slower movements when the object was placed for the partner rather than placed for self-use. Overall, these results demonstrate specific effects of action space, social uncertainty and social intention on the planning of reach-to-grasp actions, in particular on the preparatory action, which was performed with no specific execution constraint. These findings underline the importance of considering the social context in optimal models of action control for human-robot interactions, in particular when focusing on the implementation of motor parameters required to afford intuitive
String loop effect on the BRST charge
International Nuclear Information System (INIS)
Das, A.; Nishino, H.
1987-07-01
An effective BRST charge Q BRST which incorporates the string one-loop corrections is presented for the closed bosonic string in an arbitrary background. The effective σ-model action which leads to such a Q BRST is obtained and some consequences are discussed. (author). 14 refs, 1 fig
Effective climate action: why biodiversity matters | IDRC ...
International Development Research Centre (IDRC) Digital Library (Canada)
2018-05-22
May 22, 2018 ... Home · Resources · Perspectives ... This resource-dependency describes the relationship between ... involves holistic and integrated resource management strategies that ... This has been recognized in the Strategic Plan for Biodiversity ... as setting the global framework for priority actions on biodiversity.
Variational methods and effective actions in string models
International Nuclear Information System (INIS)
Dereli, T.; Tucker, R.W.
1987-01-01
Effective actions motivated by zero-order and first-order actions are examined. Particular attention is devoted to a variational procedure that is consistent with the structure equations involving the Lorentz connection. Attention is drawn to subtleties that can arise in varying higher-order actions and an efficient procedure developed to handle these cases using the calculus of forms. The effect of constrained variations on the field equations is discussed. (author)
Supergravity one-loop corrections on AdS7 and AdS3, higher spins and AdS/CFT
Directory of Open Access Journals (Sweden)
Matteo Beccaria
2015-03-01
Full Text Available As was shown earlier, the one-loop correction in 10d supergravity on AdS5×S5 corresponds to the contributions to the vacuum energy and 4d boundary conformal anomaly which are minus the values for one N=4 Maxwell supermultiplet, thus reproducing the subleading term in the N2−1 coefficient in the dual SU(N SYM theory. We perform similar one-loop computations in 11d supergravity on AdS7×S4 and 10d supergravity on AdS3×S3×T4. In the AdS7 case we find that the corrections to the 6d conformal anomaly a-coefficient and the vacuum energy are again minus the ones for one (2,0 tensor multiplet, suggesting that the total a-anomaly coefficient for the dual (2,0 theory is 4N3−9/4N−7/4 and thus vanishes for N=1. In the AdS3 case the one-loop correction to the vacuum energy or 2d central charge turns out to be equal to that of one free (4,4 scalar multiplet, i.e. is c=+6. This reproduces the subleading term in the central charge c=6(Q1Q5+1 of the dual 2d CFT describing decoupling limit of D5–D1 system. We also present the expressions for the 6d a-anomaly coefficient and vacuum energy contributions of general-symmetry higher spin field in AdS7 and consider their application to tests of vectorial AdS/CFT with the boundary conformal 6d theory represented by free scalars, spinors or rank-2 antisymmetric tensors.
Energy Technology Data Exchange (ETDEWEB)
Heinemeyer, S. [Campus of International Excellence UAM+CSIC, Madrid (Spain); Universidad Autonoma de Madrid, Cantoblanco, Instituto de Fisica Teorica (UAM/CSIC), Madrid (Spain); Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Schappacher, C.
2017-09-15
For the search for charginos and neutralinos in the Minimal Supersymmetric Standard Model (MSSM) as well as for future precision analyses of these particles an accurate knowledge of their production and decay properties is mandatory. We evaluate the cross sections for the chargino and neutralino production at e{sup +}e{sup -} colliders in the MSSM with complex parameters (cMSSM). The evaluation is based on a full one-loop calculation of the production mechanisms e{sup +}e{sup -} → χ{sub c}{sup ±}χ{sub c}{sup {sub '}-+} and e{sup +}e{sup -} → χ{sub n}{sup 0}χ{sub n}{sup {sub '}0} including soft and hard photon radiation. We mostly restricted ourselves to a version of our renormalization scheme which is valid for vertical stroke M{sub 1} vertical stroke < vertical stroke M{sub 2} vertical stroke, vertical stroke μ vertical stroke and M{sub 2} ≠ μ to simplify the analysis, even though we are able to switch to other parameter regions and correspondingly different renormalization schemes. The dependence of the chargino/neutralino cross sections on the relevant cMSSM parameters is analyzed numerically. We find sizable contributions to many production cross sections. They amount to roughly ±15% of the tree-level results but can go up to ±40% or higher in extreme cases. Also the complex phase dependence of the one-loop corrections was found non-negligible. The full one-loop contributions are thus crucial for physics analyses at a future linear e{sup +}e{sup -} collider such as the ILC or CLIC. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Kniehl, B.A.; Merebashvili, Z. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Koerner, J.G. [Mainz Univ. (Germany). Inst. fuer Physik; Rogal, M. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2008-09-15
We calculate the next-to-next-to-leading order O({alpha}{sup 4}{sub s}) one-loop squared corrections to the production of heavy quark pairs in the gluon-gluon fusion process. Together with the previously derived results on the q anti q production channel the results of this paper complete the calculation of the oneloop squared contributions of the next-to-next-to-leading order O({alpha}{sup 4}{sub s}) radiative QCD corrections to the hadroproduction of heavy flavours. Our results, with the full mass dependence retained, are presented in a closed and very compact form, in dimensional regularization. (orig.)
International Nuclear Information System (INIS)
Kniehl, B.A.; Merebashvili, Z.
2008-09-01
We calculate the next-to-next-to-leading order O(α 4 s ) one-loop squared corrections to the production of heavy quark pairs in the gluon-gluon fusion process. Together with the previously derived results on the q anti q production channel the results of this paper complete the calculation of the oneloop squared contributions of the next-to-next-to-leading order O(α 4 s ) radiative QCD corrections to the hadroproduction of heavy flavours. Our results, with the full mass dependence retained, are presented in a closed and very compact form, in dimensional regularization. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Grinstein, Benjamín [Department of Physics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093 (United States); Murphy, Christopher W. [Scuola Normale Superiore, Piazza dei Cavalieri 7, Pisa 56126 (Italy); Uttayarat, Patipan [Department of Physics, Srinakharinwirot University, Wattana, Bangkok 10110 (Thailand)
2016-06-13
We compute all of the one-loop corrections that are enhanced, O(λ{sub i}λ{sub j}/16π{sup 2}), in the limit s≫|λ{sub i}|v{sup 2}≫M{sub W}{sup 2}, s≫m{sub 12}{sup 2} to all the 2→2 longitudinal vector boson and Higgs boson scattering amplitudes in the CP-conserving two-Higgs doublet model with a softly broken ℤ{sub 2} symmetry. In the two simplified scenarios we study, the typical bound we find is |λ{sub i}(s)|⪅4.
Covariant effective action for loop quantum cosmology from order reduction
International Nuclear Information System (INIS)
Sotiriou, Thomas P.
2009-01-01
Loop quantum cosmology (LQC) seems to be predicting modified effective Friedmann equations without extra degrees of freedom. A puzzle arises if one decides to seek for a covariant effective action which would lead to the given Friedmann equation: The Einstein-Hilbert action is the only action that leads to second order field equations and, hence, there exists no covariant action which, under metric variation, leads to a modified Friedmann equation without extra degrees of freedom. It is shown that, at least for isotropic models in LQC, this issue is naturally resolved and a covariant effective action can be found if one considers higher order theories of gravity but faithfully follows effective field theory techniques. However, our analysis also raises doubts on whether a covariant description without background structures can be found for anisotropic models.
Energy Technology Data Exchange (ETDEWEB)
Heinemeyer, S. [Campus of International Excellence UAM+CSIC, Madrid (Spain); Universidad Autonoma de Madrid, Instituto de Fisica Teorica (UAM/CSIC), Madrid (Spain); Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Schappacher, C. [Karlsruhe Institute of Technology, Institut fuer Theoretische Physik, Karlsruhe (Germany)
2016-10-15
For the search for additional Higgs bosons in the Minimal Supersymmetric Standard Model (MSSM) as well as for future precision analyses in the Higgs sector precise knowledge of their production properties is mandatory. We evaluate the cross sections for the charged Higgs boson production at e{sup +}e{sup -} colliders in the MSSM with complex parameters (cMSSM). The evaluation is based on a full one-loop calculation of the production mechanism e{sup +}e{sup -} → H{sup +}H{sup -} and e{sup +}e{sup -} → H{sup ±}W{sup -+}, including soft and hard QED radiation. The dependence of the Higgs boson production cross sections on the relevant cMSSM parameters is analyzed numerically. We find sizable contributions to many cross sections. They are, depending on the production channel, roughly of 5-10 % of the tree-level results, but can go up to 20 % or higher. The full one-loop contributions are important for a future linear e{sup +}e{sup -} collider such as the ILC or CLIC. (orig.)
Effective actions for gauge theories with Chern-Simons terms - I
International Nuclear Information System (INIS)
Bambah, B.A.; Mukku, C.
1989-01-01
The effective Lagrangian for a three-dimensional gauge theory with a Chern-Simons term is evaluated upto one-loop effects. It is shown to be completely finite. It also does not exhibit any imaginary part. The calculation is carried out in a background field analogue of the Feynman gauge and gauge invariance is maintained throughout the calculation. In an appendix an argument is presented as to why this Feynman gauge may be a 'good' gauge for our results to be applied to high temperature QCD and in particular to the quark-gluon plasma. (author). 12 refs
International Nuclear Information System (INIS)
Phillips, S.
1985-01-01
An alternative formulation of path-integral quantization for gauge theories is proposed in which the gauge-fixing condition, normally imposed on just the gauge field itself, is imposed on the gauge-transformed gauge field, a continuous sum now being included over all configurations of the transformation field, Λ(x) that satisfy the gauge condition. It is shown, by explicit calculation, that when bilinear counterterms in the Lagrangian field density are included so as to render the two-point gauge- and fermion-field Green's functions finite, the fermion-fermion-gauge-field Green's function is divergence free. Unlike the more conventional approaches, there is no divergent vertex counterterm needed. Furthermore, the form of the fermion counterterm is a simple mass insertion only. There is no need for a divergent fermion wave-function renormalization. The cancellation of the divergences that are normally present is accomplished by the effect of, heretofor uncommon in perturbative quantum-field theory, infrared-divergent integrals. It is argued heuristically how these may be regulated by the same parameter, Λ, that is used for ultraviolet-divergent integrals, where now the cutoff is towards the lower limit of integration
Techniques for calculations with nPI effective actions
Directory of Open Access Journals (Sweden)
Carrington M.E.
2015-01-01
Full Text Available We consider a symmetric scalar theory with quartic coupling in 2- and 3- dimensions and compare the self-consistent 4-point vertex obtained from the 4PI effective action with the Bethe-Salpeter 4-vertex from 2PI effective action. We show that when the coupling is large the contributions from the higher order effective action are large. We also show that one can solve the 2PI equations of motion in 4-dimensions, without introducing counter-terms, using a renormalization group method. This method provides a promising starting point to study the renormalization of higher order nPI theories.
On the influence of reward on action-effect binding
Directory of Open Access Journals (Sweden)
Paul Simon Muhle-Karbe
2012-11-01
Full Text Available Ideomotor theory states that the formation of anticipatory representations about the perceptual consequences of an action (i.e. action-effect (A-E binding provides the functional basis of voluntary action control. A host of studies has demonstrated that A-E binding occurs fast and effortlessly, yet only little is known about cognitive and affective factors that influence this learning process. In the present study, we sought to test whether the motivational value of an action modulates the acquisition of A-E associations. To this end, we associated specific actions with monetary incentives during the acquisition of novel A-E mappings. In a subsequent test phase, the degree of binding was assessed by presenting the former effect stimuli as task-irrelevant response primes in a forced-choice response task in the absence of any reward. Binding, as indexed by response priming through the former action effects, was only found for reward-related A-E mappings. Moreover, the degree to which reward associations modulated the binding strength was predicted by individuals’ trait sensitivity to reward. These observations indicate that the association of actions and their immediate outcomes depends on the motivational value of the action during learning, as well as on the motivational disposition of the individual. On a larger scale, these findings also highlight the link between ideomotor theories and reinforcement-learning theories, providing an interesting perspective for future research on anticipatory regulation of behavior.
The internal anticipation of sensory action effects: when action induces FFA and PPA activity
Directory of Open Access Journals (Sweden)
Simone Kühn
2010-06-01
Full Text Available Voluntary action – in particular the ability to produce desired effects in the environment – is fundamental to human existence. According to ideomotor theory we can achieve goals in the environment by means of anticipating their outcomes. We aimed at providing neurophysiological evidence for the assumption that performing actions calls for the activation of brain areas associated with the sensory effects usually evoked by the actions. We conducted an fMRI study in which right and left button presses lead to the presentation of face and house pictures. We compared a baseline phase with the same phase after participants experienced the association between button presses and pictures. We found an increase in the parahippocampal place area (PPA for the response that has been associated with house pictures and fusiform face area (FFA for the response that has been coupled with face pictures. This observation constitutes support for ideomotor theory.
17 CFR 9.12 - Effective date of disciplinary or access denial action.
2010-04-01
... ACTIONS Notice and Effective Date of Disciplinary Action or Access Denial Action § 9.12 Effective date of disciplinary or access denial action. (a) Effective date. Any disciplinary or access denial action taken by an... cause a disciplinary action to become effective prior to that time if: (1) As authorized by § 8.25 of...
Effective average action for gauge theories and exact evolution equations
International Nuclear Information System (INIS)
Reuter, M.; Wetterich, C.
1993-11-01
We propose a new nonperturbative evolution equation for Yang-Mills theories. It describes the scale dependence of an effective action. The running of the nonabelian gauge coupling in arbitrary dimension is computed. (orig.)
Low-energy effective action for the superstring
International Nuclear Information System (INIS)
Burgess, C.P.; Font, A.; Quevedo, F.
1986-01-01
We construct the low-energy D=4, N=1 supergravity that arises in superstring theories for an arbitrary number of generations. The coupling of all massless modes that carry low-energy gauge quantum numbers are calculated by truncating the heavy Kaluza-Klein modes of the ten-dimensional effective field theory. The resulting action is compared to the most general effective action compatible with the symmetries of the underlying ten-dimensional field (and string) theories. This comparison indicates which features of the truncation correctly approximate the exact low-energy action. (orig.)
Mechhoud, Sarra; Laleg-Kirati, Taous-Meriem
2017-01-01
In this paper, the adaptive bilinear control of a first-order 1-D hyperbolic partial differential equation (PDE) with an unknown time-varying source term is investigated where only boundary measurements are available. By means of boundary injection, the bilinear adaptive law is developed in the Lyapunov approach. It consists of a state observer and an input adaptation law combined with a bilinear control method derived using an energy-like principle. Both global asymptotic practical convergence of the tracking error and input-to-state stability of the system are guaranteed. A potential application of this control strategy is the one-loop solar collector parabolic trough where the solar irradiance is the unknown input (source term) and the flow rate is the control variable. The objective is to drive the boundary temperature at the outlet to track a desired profile. Simulation results are provided to illustrate the performance of the proposed method.
International Nuclear Information System (INIS)
Liu Jing; Ma Wengan; Zhang Renyu; Guo Lei; Jiang Yi; Han Liang
2007-01-01
We study the complete one-loop electroweak (EW) corrections to the processes of single charged Higgs boson production associated with a neutral Higgs boson (h 0 ,H 0 ,A 0 ) and a gauge boson W ± in the framework of the minimal supersymmetric standard model (MSSM). Numerical results at the SPS1a ' benchmark point as proposed in the SPA project, are presented for demonstration. We find that for the process e + e - →h 0 H ± W ± the EW relative correction can be either positive or negative and in the range of -15%∼20% in our chosen parameter space. While for the processes e + e - →H 0 (A 0 )H ± W ± the corrections generally reduce the Born cross sections and the EW relative corrections are typically of order -10%∼-20%
Mechhoud, Sarra
2017-12-14
In this paper, the adaptive bilinear control of a first-order 1-D hyperbolic partial differential equation (PDE) with an unknown time-varying source term is investigated where only boundary measurements are available. By means of boundary injection, the bilinear adaptive law is developed in the Lyapunov approach. It consists of a state observer and an input adaptation law combined with a bilinear control method derived using an energy-like principle. Both global asymptotic practical convergence of the tracking error and input-to-state stability of the system are guaranteed. A potential application of this control strategy is the one-loop solar collector parabolic trough where the solar irradiance is the unknown input (source term) and the flow rate is the control variable. The objective is to drive the boundary temperature at the outlet to track a desired profile. Simulation results are provided to illustrate the performance of the proposed method.
Type I supergravity effective action from pure spinor formalism
International Nuclear Information System (INIS)
Alencar, Geova
2009-01-01
Using the pure spinor formalism, we compute the tree-level correlation functions for three strings, one closed and two open, in N = 1 D = 10 superspace. Expanding the superfields in components, the respective terms of the effective action for the type I supergravity are obtained. All terms found agree with the effective action known in the literature. This result gives one more consistency test for the pure spinor formalism.
Urban Heat Island Effect Actions - Neighborhood Data
Louisville Metro Government — The urban heat island effect — defined as the difference in temperature between the core of Louisville and its suburbs — contributes to heat-related illnesses and...
Radiosensitizers action on Iodine 131 therapeutical effect
International Nuclear Information System (INIS)
Agote, Marcos; Kreimann, Erica L.; Bocanera, Laura V.; Dagrosa, Maria A.; Juvenal, Guillermo J.; Pisarev, Mario A.
1999-01-01
Present studies were aimed to research the possible application of a radiosensitizer, nicotinamide, to increase the therapeutical effect of radioiodine. There were used goitrous and normal rats with growing dose of Iodine 131, with and without simultaneous treatment with nicotinamide. The obtained results show that the nicotinamide treatment importantly increases the thyroid radio destructive effect induced by radioiodine. Under these experimental conditions, nicotinamide induces to a significant increase of thyroid vascularisation, without changes in the proteins ADP-ribosylation activity. These results show, for the first time, the radiosensitizer effect of nicotinamide in front of Iodine 131 and give the possibility of using it in the treatment of hyperthyroid or thyroid difference cancer patients. (author)
Open rigid string with the Gauss-Bonnet term in action
International Nuclear Information System (INIS)
Nesterenko, V.V.; Pirozhenko, I.G.
1998-01-01
The effect of the Gaussian curvature in the rigid string action on the interquark potential is investigated. The linearized equations of motion and boundary conditions, following from the modified string action, are obtained. The equation, defining the eigenfrequency spectrum of the string oscillations is derived. On this basis the interquark potential generated by the string is calculated in one-loop approximation. A substantial influence of the topological term in the string action on the interquark potential at the distances of hadronic size order or less is revealed
Effect of mutagen combined action on Chlamydomonas reinhardtii cells. II
International Nuclear Information System (INIS)
Podstavkova, S.; Vlcek, D.; Dubovsky, J.
1978-01-01
The effect of UV radiation and UV radiation combined with alkylnitrosourea derivatives (N-methyl-N-nitrosourea and N-ethyl-N-nitrosourea) was observed on survival of cells of the algae Chlamydomonas reinhardtii. In particular, single parts were evaluated of the overall lethal effect - dying of cells before division and dying of cells after division. It was found that the combined action of low doses of UV radiation and alkylnitrosoureas result in a pronounced protective effect which manifests itself by a higher frequency of surviving cells than was that effected by the action of alkylnitrosoureas alone. As a result of combined action with higher doses of UV radiation this effect is lost, and the resultant values will come close to the theoretically anticipated values. This gradual transition from a protective to an additive effect mainly manifests itself by changes in the proportion of cells dying before division. (author)
Renormalization and effective actions for general relativity
International Nuclear Information System (INIS)
Neugebohrn, F.
2007-05-01
Quantum gravity is analyzed from the viewpoint of the renormalization group. The analysis is based on methods introduced by J. Polchinski concerning the perturbative renormalization with flow equations. In the first part of this work, the program of renormalization with flow equations is reviewed and then extended to effective field theories that have a finite UV cutoff. This is done for a scalar field theory by imposing additional renormalization conditions for some of the nonrenormalizable couplings. It turns out that one so obtains a statement on the predictivity of the effective theory at scales far below the UV cutoff. In particular, nonrenormalizable theories can be treated without problems in the proposed framework. In the second part, the standard covariant BRS quantization program for Euclidean Einstein gravity is applied. A momentum cutoff regularization is imposed and the resulting violation of the Slavnov-Taylor identities is discussed. Deriving Polchinski's renormalization group equation for Euclidean quantum gravity, the predictivity of effective quantum gravity at scales far below the Planck scale is investigated with flow equations. A fine-tuning procedure for restoring the violated Slavnov-Taylor identities is proposed and it is argued that in the effective quantum gravity context, the restoration will only be accomplished with finite accuracy. Finally, the no-cutoff limit of Euclidean quantum gravity is analyzed from the viewpoint of the Polchinski method. It is speculated whether a limit with nonvanishing gravitational constant might exist where the latter would ultimatively be determined by the cosmological constant and the masses of the elementary particles. (orig.)
Renormalization and effective actions for general relativity
Energy Technology Data Exchange (ETDEWEB)
Neugebohrn, F.
2007-05-15
Quantum gravity is analyzed from the viewpoint of the renormalization group. The analysis is based on methods introduced by J. Polchinski concerning the perturbative renormalization with flow equations. In the first part of this work, the program of renormalization with flow equations is reviewed and then extended to effective field theories that have a finite UV cutoff. This is done for a scalar field theory by imposing additional renormalization conditions for some of the nonrenormalizable couplings. It turns out that one so obtains a statement on the predictivity of the effective theory at scales far below the UV cutoff. In particular, nonrenormalizable theories can be treated without problems in the proposed framework. In the second part, the standard covariant BRS quantization program for Euclidean Einstein gravity is applied. A momentum cutoff regularization is imposed and the resulting violation of the Slavnov-Taylor identities is discussed. Deriving Polchinski's renormalization group equation for Euclidean quantum gravity, the predictivity of effective quantum gravity at scales far below the Planck scale is investigated with flow equations. A fine-tuning procedure for restoring the violated Slavnov-Taylor identities is proposed and it is argued that in the effective quantum gravity context, the restoration will only be accomplished with finite accuracy. Finally, the no-cutoff limit of Euclidean quantum gravity is analyzed from the viewpoint of the Polchinski method. It is speculated whether a limit with nonvanishing gravitational constant might exist where the latter would ultimatively be determined by the cosmological constant and the masses of the elementary particles. (orig.)
Duality symmetries and the Type II string effective action
International Nuclear Information System (INIS)
Bergshoeff, E.
1996-01-01
We discuss the duality symmetries of Type II string effective actions in nine, ten and eleven dimensions. As a by-product we give a covariant action underlying the ten-dimensional Type IIB supergravity theory. We apply duality symmetries to construct dyonic Type II string solutions in six dimensions and their reformulation as solutions of the ten-dimensional Type IIB theory in ten dimensions. (orig.)
Perception, action, and Roelofs effect: a mere illusion of dissociation.
Directory of Open Access Journals (Sweden)
Paul Dassonville
2004-11-01
Full Text Available A prominent and influential hypothesis of vision suggests the existence of two separate visual systems within the brain, one creating our perception of the world and another guiding our actions within it. The induced Roelofs effect has been described as providing strong evidence for this perception/action dissociation: When a small visual target is surrounded by a large frame positioned so that the frame's center is offset from the observer's midline, the perceived location of the target is shifted in the direction opposite the frame's offset. In spite of this perceptual mislocalization, however, the observer can accurately guide movements to the target location. Thus, perception is prone to the illusion while actions seem immune. Here we demonstrate that the Roelofs illusion is caused by a frame-induced transient distortion of the observer's apparent midline. We further demonstrate that actions guided to targets within this same distorted egocentric reference frame are fully expected to be accurate, since the errors of target localization will exactly cancel the errors of motor guidance. These findings provide a mechanistic explanation for the various perceptual and motor effects of the induced Roelofs illusion without requiring the existence of separate neural systems for perception and action. Given this, the behavioral dissociation that accompanies the Roelofs effect cannot be considered evidence of a dissociation of perception and action. This indicates a general need to re-evaluate the broad class of evidence purported to support this hypothesized dissociation.
Early markers of ongoing action-effect learning
Directory of Open Access Journals (Sweden)
Hannes eRuge
2012-11-01
Full Text Available Acquiring knowledge about the relationship between stimulus conditions, one’s own actions, and the resulting consequences or effects, is one prerequisite for intentional action. Previous studies have shown that such contextualized associations between actions and their effects (S-R-E associations can be picked up very quickly. The present study examined how such weakly practiced associations might affect overt behavior during the process of initial learning and during subsequent retrieval, and how these two measures are inter-related. We examined incidental (S-R-E learning in the context of trial-and-error S-R learning and in the context of instruction-based S-R learning. Furthermore, as a control condition, common outcome (CO learning blocks were included in which all responses produced one common sound effect, hence precluding differential (S-R-E learning. Post-learning retrieval of R-E associations was tested by re-using previously produced sound effects as novel imperative stimuli combined with actions that were either compatible or incompatible with the previously encountered R-E mapping. The central result was that the size of the compatibility effect could be predicted by the size of relative response slowing during ongoing learning in the preceding acquisition phase, both in trial-and-error learning and in instruction-based learning. Importantly, this correlation was absent for the common outcome control condition, precluding accounts based on unspecific factors. Instead, the results suggest that differential outcomes are ‘actively’ integrated into action planning and that this takes additional planning time. We speculate that this might be especially true for weakly practiced (S-R-E associations before an initial goal-directed action mode transitions into a more stimulus-based action mode.
Selective effects of an octopus toxin on action potentials
Dulhunty, Angela; Gage, Peter W.
1971-01-01
1. A lethal, water soluble toxin (Maculotoxin, MTX) with a molecular weight less than 540, can be extracted from the salivary glands of an octopus (Hapalochlaena maculosa). 2. MTX blocks action potentials in sartorius muscle fibres of toads without affecting the membrane potential. Delayed rectification is not inhibited by the toxin. 3. At low concentrations (10-6-10-5 g/ml.) MTX blocks action potentials only after a certain number have been elicited. The number of action potentials, which can be defined accurately, depends on the concentration of MTX and the concentration of sodium ions in the extracellular solution. 4. The toxin has no post-synaptic effect at the neuromuscular junction and it is concluded that it blocks neuromuscular transmission by inhibiting action potentials in motor nerve terminals. PMID:4330930
The Effect of Sympathetic Antagonists on the Antidepressant Action ...
African Journals Online (AJOL)
Alprazolam is an anti-anxiety drug shown to be effective in the treatment of depression. In this study, the effect of sympathetic receptor antagonists on alprazolam–induced antidepressant action was studied using a mouse model of forced swimming behavioral despair. The interaction of three sympathetic receptor ...
Power effects on cognitive control: Turning conflict into action.
Schmid, Petra C; Kleiman, Tali; Amodio, David M
2015-06-01
Power is known to promote effective goal pursuit, especially when it requires one to overcome distractions or bias. We proposed that this effect involves the ability to engage and implement cognitive control. In Study 1, we demonstrated that power enhances behavioral performance on a response conflict task and that it does so by enhancing controlled processing rather than by reducing automatic processing. In Study 2, we used an event-related potential index of anterior cingulate activity to test whether power effects on control were due to enhanced conflict sensitivity or action implementation. Power did not significantly affect neural sensitivity to conflict; rather, high power was associated with a stronger link between conflict processing and intended action, relative to low power. These findings suggest a new perspective on how social factors can affect controlled processing and offer new evidence regarding the transition between conflict detection and the implementation of action control. (c) 2015 APA, all rights reserved).
Developing Effective Corrective Action Plan in Krsko NPP
International Nuclear Information System (INIS)
Bach, Bruno; Cizmek, Rudi; Bozin, Bojan
2014-01-01
Experience shows that many events could have been prevented if lessons had been learned from previous incidents. Event reporting thus has become an increasingly important aspect of the operation and regulation of all safety-related and public health industries. Different industries such as aeronautics, chemicals, transport and of course nuclear depend on Operating Experience (OE) feedback programs to provide lessons learned about safety. The information available under an OE programme for these organizations comprises internal event reports and analysis and external operating experience including reports on low level events and near misses and other relevant operating performance information. The worldwide OE programme (such as WANO OE) in nuclear power plants provides opportunity to learn from events at other plants. In particular, it alerts plants to mistakes or events that have occurred at other nuclear power plants and enables them to take corrective actions to prevent similar occurrences at their own plant. The intent of the effective and efficient OE program is therefore to improve personnel/plant safety, reliability and commercial performance of the operating nuclear power plants. Such a programme ensures that operating experience is analysed, events important to safety are reviewed in depth, lessons learned are disseminated to the staff and to the relevant national and international organizations and corrective actions are effectively implemented. Learning and applying the lessons from operating experience is an integral part of station safety culture and is encouraged by managers throughout the top plant administrative programs and procedures. Krsko NPP is developed its own OE program by using the most relevant INPO/WANO/IAEA guidelines as well as its own knowledge, skills an operating practice. The OE is a part of the Corrective Action Program (CAP), which is among top management programs. The purpose of this article is to present a part of the Krško NPP
Localization of effective actions in open superstring field theory
Maccaferri, Carlo; Merlano, Alberto
2018-03-01
We consider the construction of the algebraic part of D-branes tree-level effective action from Berkovits open superstring field theory. Applying this construction to the quartic potential of massless fields carrying a specific worldsheet charge, we show that the full contribution to the potential localizes at the boundary of moduli space, reducing to elementary two-point functions. As examples of this general mechanism, we show how the Yang-Mills quartic potential and the instanton effective action of a Dp/D( p - 4) system are reproduced.
Exceptional F(4) higher-spin theory in AdS{sub 6} at one-loop and other tests of duality
Energy Technology Data Exchange (ETDEWEB)
Günaydin, Murat [Institute for Gravitation and the Cosmos Physics Department, Pennsylvania State University, University Park, PA 16802 (United States); Skvortsov, Evgeny [Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians University Munich, Theresienstr. 37, D-80333 Munich (Germany); Lebedev Institute of Physics, Leninsky ave. 53, 119991 Moscow (Russian Federation); Tran, Tung [Department of Physics, Brown University, Providence, Rhode Island 02912 (United States)
2016-11-28
We study the higher-spin gauge theory in six-dimensional anti-de Sitter space AdS{sub 6} that is based on the exceptional Lie superalgebra F(4). The relevant higher-spin algebra was constructed in http://arxiv.org/abs/1409.2185. We determine the spectrum of the theory and show that it contains the physical fields of the Romans F(4) gauged supergravity. The full spectrum consists of an infinite tower of unitary supermultiplets of F(4) which extend the Romans multiplet to higher spins plus a single short supermultiplet. Motivated by applications to this novel supersymmetric higher-spin theory as well as to other theories, we extend the known one-loop tests of AdS/CFT duality in various directions. The spectral zeta-function is derived for the most general case of fermionic and mixed-symmetry fields, which allows one to test the Type-A and B theories and supersymmetric extensions thereof in any dimension. We also study higher-spin doubletons and partially-massless fields. While most of the tests are successfully passed, the Type-B theory in all even dimensional anti-de Sitter spacetimes presents an interesting puzzle: the free energy as computed from the bulk is not equal to that of the free fermion on the CFT side, though there is some systematics to the discrepancy.
The Born-Infeld action from conformal invariance of the open superstring
International Nuclear Information System (INIS)
Bergshoeff, E.; Sezgin, E.; Pope, C.N.; Townsend, P.K.
1987-01-01
We show that the one-loop approximation to sigma-model perturbation theory for the open superstring leads to the low energy effective action of Born-Infeld for the gauge field coupled to the ends of the string. Thus the bosonic part of the low-energy open superstring effective action is just that of the open bosonic string. We also show that these results are exact to all-loop orders of sigma-model perturbation theory. (author). 12 refs, 5 figs
Nonlocal quantum effective actions in Weyl-Flat spacetimes
Bautista, Teresa; Benevides, André; Dabholkar, Atish
2018-06-01
Virtual massless particles in quantum loops lead to nonlocal effects which can have interesting consequences, for example, for primordial magnetogenesis in cosmology or for computing finite N corrections in holography. We describe how the quantum effective actions summarizing these effects can be computed efficiently for Weyl-flat metrics by integrating the Weyl anomaly or, equivalently, the local renormalization group equation. This method relies only on the local Schwinger-DeWitt expansion of the heat kernel and allows for a re-summation of the anomalous leading large logarithms of the scale factor, log a( x), in situations where the Weyl factor changes by several e-foldings. As an illustration, we obtain the quantum effective action for the Yang-Mills field coupled to massless matter, and the self-interacting massless scalar field. Our action reduces to the nonlocal action obtained using the Barvinsky-Vilkovisky covariant perturbation theory in the regime R 2 ≪ ∇2 R for a typical curvature scale R, but has a greater range of validity effectively re-summing the covariant perturbation theory to all orders in curvatures. In particular, it is applicable also in the opposite regime R 2 ≫ ∇2 R, which is often of interest in cosmology.
The background effective average action approach to quantum gravity
DEFF Research Database (Denmark)
D’Odorico, G.; Codello, A.; Pagani, C.
2016-01-01
of an UV attractive non-Gaussian fixed-point, which we find characterized by real critical exponents. Our closure method is general and can be applied systematically to more general truncations of the gravitational effective average action. © Springer International Publishing Switzerland 2016....
BEPS Action 2: Neutralizing the Effects on Hybrid Mismatch Arrangements
de Boer, R.; Marres, O.
2015-01-01
Curbing tax arbitrage is one of the main priorities of the Organization for Economic Cooperation and Development (OECD) (endorsed by the G20 and the G8) ever since the public debate on base erosion fully erupted. Neutralizing the effect of hybrid mismatch arrangements has become Action No. 2 of the
Action Research: Effective Marketing Strategies for a Blended University Program
Cook, Ruth Gannon; Ley, Kathryn
2008-01-01
This action research study investigated a marketing plan based on collaboration among a program faculty team and other organizational units for a graduate professional program. From its inception through the second year of operation, program enrollment increased due to the marketing plan based on an effective approach grounded in simple marketing…
Effective action and β-functions for the heterotic string
International Nuclear Information System (INIS)
Foakes, A.P.; Mohammedi, N.; Ross, D.A.
1988-01-01
The results of the calculation of the metric β-function for the heterotic string sigma model up to three loops are presented and it is shown that although this β-function is non vanishing it is compatible with an O((α') 2 ) effective action in which there are no terms cubic in the Riemann tensor or gauge field strength. (orig.)
Action video game training reduces the Simon Effect.
Hutchinson, Claire V; Barrett, Doug J K; Nitka, Aleksander; Raynes, Kerry
2016-04-01
A number of studies have shown that training on action video games improves various aspects of visual cognition including selective attention and inhibitory control. Here, we demonstrate that action video game play can also reduce the Simon Effect, and, hence, may have the potential to improve response selection during the planning and execution of goal-directed action. Non-game-players were randomly assigned to one of four groups; two trained on a first-person-shooter game (Call of Duty) on either Microsoft Xbox or Nintendo DS, one trained on a visual training game for Nintendo DS, and a control group who received no training. Response times were used to contrast performance before and after training on a behavioral assay designed to manipulate stimulus-response compatibility (the Simon Task). The results revealed significantly faster response times and a reduced cost of stimulus-response incompatibility in the groups trained on the first-person-shooter game. No benefit of training was observed in the control group or the group trained on the visual training game. These findings are consistent with previous evidence that action game play elicits plastic changes in the neural circuits that serve attentional control, and suggest training may facilitate goal-directed action by improving players' ability to resolve conflict during response selection and execution.
Adiabatic effective action for vortices in neutral and charged superfluids
International Nuclear Information System (INIS)
Hatsuda, M.; Sato, M.; Yahikozawa, S.; Hatsuda, T.
1996-01-01
Adiabatic effective action for vortices in neutral and charged superfluids at zero temperature are calculated using the topological Landau-Ginzburg theory recently proposed by Hatsuda, Yahikozawa, Ao and Thouless, and vortex dynamics are examined. The Berry phase term arising in the effective action naturally yields the Magnus force in both neutral and charged superfluids. It is shown that in neutral superfluid there is only one degree of freedom, namely the center of vorticities, and the vortex energy is proportional to the sum of all vorticities so that it is finite only for the vanishing total vorticity of the system. On the other hand the effective mass and the vortex energy for a vortex in charged superfluids are defined individually as expected. The effects of the vortex core on these quantities are also estimated. The possible depinning scenario which is governed by the Magnus force and the inertial mass is also discussed
Effect of mutagen combined action on Chlamydomonas Reinhardtii cells. I
International Nuclear Information System (INIS)
Vlcek, D.; Podstavkova, S.; Dubovsky, J.
1978-01-01
The effect was investigated of single and combined actions of alkylnitrosourea derivatives (N-methyl-N-nitrosourea and N-ethyl-N-nitrosourea) and UV-radiation on the survival of cells of Chlamydomonas reinhardtii algae in dependence on the sequence of application of mutagens and on the given conditions of cultivation following mutagen activity. In particular, the single phases were investigated of the total lethal effect, i.e., the death of cells before division and their death after division. The most pronounced changes in dependence on the sequence of application of mutagens and on the given conditions of cultivation were noted in cell death before division. In dependence on the sequence of application of mutagens, the effect of the combined action on the survival of cells changed from an additive (alkylnitrosourea + UV-radiation) to a protective effect (UV-radiation + alkylnitrosourea). (author)
Perturbative determination of c{sub SW} with Symanzik improved gauge action and stout smearing
Energy Technology Data Exchange (ETDEWEB)
Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics; Perlt, H.; Schiller, A. [Leipzig Univ. (Germany). Inst. fuer Theoretische Physik; Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Dept., Dept. of Mathematical Sciences; Schierholz, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2007-10-15
We determine the improvement factor c{sub SW} in one-loop lattice perturbation theory for the plaquette and Symanzik improved gauge actions. The fermionic action is O(a) clover improved with one-time stout smearing. c{sub SW} is derived from the one-loop correction to the quark-quark-gluon vertex in the off-shell regime. We give a first numerical value for the one-loop contribution to the non gauge-invariant improvement coefficient c{sub NGI} for the quark field using the plaquette action. A discussion of mean field improvement is included. (orig.)
Effect of exercise on insulin action in human skeletal muscle
DEFF Research Database (Denmark)
Richter, Erik; Mikines, K J; Galbo, Henrik
1989-01-01
The effect of 1 h of dynamic one-legged exercise on insulin action in human muscle was studied in 6 healthy young men. Four hours after one-legged knee extensions, a three-step sequential euglycemic hyperinsulinemic clamp combined with arterial and bilateral femoral vein catheterization...... was performed. Increased insulin action on glucose uptake was found in the exercised compared with the rested thigh at mean plasma insulin concentrations of 23, 40, and 410 microU/ml. Furthermore, prior contractions directed glucose uptake toward glycogen synthesis and increased insulin effects on thigh O2...... consumption and at some insulin concentrations on potassium exchange. In contrast, no change in insulin effects on limb exchange of free fatty acids, glycerol, alanine or tyrosine were found after exercise. Glycogen concentration in rested vastus lateralis muscle did not increase measurably during the clamp...
Disarming the gunslinger effect: Reaction beats intention for cooperative actions.
Weller, Lisa; Kunde, Wilfried; Pfister, Roland
2018-04-01
According to the famous physicist Niels Bohr, gunfights at high noon in Western movies not only captivate the cinema audience but also provide an accurate illustration of a psychophysical law. He suggested that willed actions come with slower movement execution than reactions, and therefore that a film's hero is able to get the upper hand even though the villain normally draws first. A corresponding "gunslinger effect" has been substantiated by empirical studies. Because these studies used a markedly competitive setting, however, it is currently unclear whether the gunslinger effect indeed reflects structural differences between willed actions and reactive movements, or whether it is a by-product of the competitive setting. To obtain bullet-proof evidence for a true reactive advantage, we investigated willed and reactive movements during a cooperative interaction of two participants. A pronounced reactive advantage emerged, indicating that two independent systems indeed control willed and reactive movements.
Hard thermal loops, static response, and the composite effective action
International Nuclear Information System (INIS)
Jackiw, R.; Liu, Q.; Lucchesi, C.
1994-01-01
First, we investigate the static non-Abelian Kubo equation. We prove that it does not possess finite energy solutions; thereby we establish that gauge theories do not support hard thermal solitons. This general result is verified by a numerical solution of the equations. A similar argument shows that ''static'' instantons are absent. In addition, we note that the static equations reproduce the expected screening of the non-Abelian electric field by a gauge-invariant Debye mass m=gT √(N+N F /2)/3 . Second, we derive the non-Abelian Kubo equation from the composite effective action. This is achieved by showing that the requirement of stationarity of the composite effective action is equivalent, within a kinematical approximation scheme, to the condition of gauge invariance for the generating functional of hard thermal loops
Using the Psychology of Language to Effectively Communicate Actionable Science
Hall, J. M.
2014-12-01
The words used to articulate science can have as significant a psychological impact on public perception as the data itself. It is therefore essential to utilize language that not only accurately relates the scientific information, but also effectively conveys a message that is congruent with the presenter's motivation for expressing the data. This is especially relevant for environmental subjects that are surrounded by emotionally charged, political discourses. For example are terms like catastrophe and disaster; while these words may accurately illustrate impartial scientific data, they will likely trigger psychological responses in audiences such as fear or denial that have a detrimental impact on the human decision making process. I propose a set of 5 key principles to assist in communicating data to the general public that both support the transfer of ideas and the presenter's intended psychological impact. 1) Articulate the underlying intentions that motivate the communication of data in a transparent manner 2) Use language congruent with the presenter's stated intentions 3) Maintain a neutral, non-judgmental attitude towards the complex human psychological and emotional dynamics present in a target audience 4) Demonstrate acceptance and compassion when analyzing past and present human actions that adversely affect the environment 5) Develop a perspective of non-attachment when proposing future actions and/or consequences of current human behaviors. The application of these 5 principles provides a framework to move from our current understanding of problems and solutions to effective physical action that allows us to gracefully adapt with our ever changing planet.
Toward effective ecological risk-management of refinery corrective action
International Nuclear Information System (INIS)
Metzger, B.H.; Rury, P.M.; Turton, D.; Archibald, B.; Clark, J.; Cura, J.
1995-01-01
Cleanup of complex industrial sites, such as refineries, requires risk-based decision tools to ensure that environmentally protective remediation is consistent with current and future land use. However, conventional ecological risk assessment approaches are not well suited for complex industrial sites. Site risk assessments focus on hypothetical chemical risk assuming diverse and undisturbed ecosystems, rather than industrial and disturbed area conditions. In addition, they offer little guidance as to how to make timely and effective risk management decisions. An innovative methodology is proposed to assist industry and regulatory risk managers with rapid EcoRisk reconnaissance and cost-effective remedial decision-making at complex industrial sites. Phase 1 comprises a three-step risk screening of areas of ecological concern at the site, which integrates habitat quality characteristics and potential chemical hazards. It yields an ordering of areas as follows: areas of no significant risk; areas of potentially significant risk; and areas of likely significant risk. A decision rule is then applied to determine appropriate risk management action, including: no action; additional study; and remedial or management action. In Phase 2, additional study is conducted for areas that exhibit potentially significant risk so as to facilitate risk management. This methodology is currently being applied at the 1,300 acre, former Exxon Bayway Refinery in New Jersey
International Nuclear Information System (INIS)
Manente, Francine Alessandra; Mello, Lucas Rosolen de Almeida; Vellosa, Jose Carlos Rebuglio; Khalil, Omar Arafat Kdudsi; Carvalho, Claudio Teodoro de; Bannach, Gilbert
2011-01-01
Free radicals are highly reactive species generated in living organisms for the purpose of protection. However, in some circumstances, they are responsible for the occurrence or aggravation of tissue damage. Many anti-inflammatory drugs have a direct effect on free radicals and not radical reactive species, which contributes to its actions against inflammation. Ketoprofen is a nonsteroidal anti-inflammatory agent that generates free radicals by photo irradiation and has an important hemolytic effect with that. The complexation of metals to different drugs has been used as a strategy to improve the pharmacological action of different molecules and reduce their side effects. This paper presents the results of ketoprofen and their metallic complexes action on erythrocytes and free radicals. It was observed that the cerium enhances the scavenger properties of ketoprofen on free radicals, while copper enhances its action over non-radical oxidants. Copper also reduced the hemolytic effect presented by ketoprofen meanwhile its cerium derivative maintained it. (author)
Directory of Open Access Journals (Sweden)
Takahiro eKawabe
2013-09-01
Full Text Available Humans can acquire the statistical features of the external world and employ them to control behaviors. Some external events occur in harmony with an agent’s action, and thus humans should also be able to acquire the statistical features between an action and its external outcome. We report that the acquired action-outcome statistical features alter the visual appearance of the action outcome. Pressing either of two assigned keys triggered visual motion whose direction was statistically biased either upward or downward, and observers judged the stimulus motion direction. Points of subjective equality (PSE for judging motion direction were shifted repulsively from the mean of the distribution associated with each key. Our Bayesian model accounted for the PSE shifts, indicating the optimal acquisition of the action-effect statistical relation. The PSE shifts were moderately attenuated when the action-outcome contingency was reduced. The Bayesian model again accounted for the attenuated PSE shifts. On the other hand, when the action-outcome contiguity was greatly reduced, the PSE shifts were greatly attenuated, and however, the Bayesian model could not accounted for the shifts. The results indicate that visual appearance can be modified by prediction based on the optimal acquisition of action-effect causal relation.
Gas action effect of free piston Stirling engine
International Nuclear Information System (INIS)
Mou, Jian; Li, Wei; Li, Jinze; Hong, Guotong
2016-01-01
Highlights: • The gas action effect is analyzed by the method of rotation vector decomposition. • Gas force can be decomposed into motivation force and spring or inertia force. • The optimal phase angles of displacements to pressure wave have been found. - Abstract: Gas action effect of free piston Stirling engine (FPSE) is very important to solve the key problem of start-up and find the way to increase its efficiency. The gas force is a key force to free FPSE. In this paper, the gas action effect has been analyzed by the method of rotation vector decomposition. It is found that the gas forces of piston and displacer can be decomposed into two forces, one component acts as motivation force resisting the damping force to output power, the other acts as spring force or inertia force according to the phase angle of pressure wave to displacements of the displacer and piston. Only when the motivation components of both piston and displacer resist their damping forces, will the FPSE be start-up and work stably. And only when the spring force is approximately equal to inertia force of piston, will the piston need the smallest gas spring force and nearly all the gas force be put for the alternator, meanwhile the engine outputs the maximum work. In the perfect condition, the optimal phase angle of the reciprocating movements of the displacer and piston ahead of the pressure wave are 180° and 90° respectively. The analyses above are verified by a series of experiments on a FPSE designed by our laboratory.
Hawking radiation, effective actions and covariant boundary conditions
International Nuclear Information System (INIS)
Banerjee, Rabin; Kulkarni, Shailesh
2008-01-01
From an appropriate expression for the effective action, the Hawking radiation from charged black holes is derived, using only covariant boundary conditions at the event horizon. The connection of our approach with the Unruh vacuum and the recent analysis [S.P. Robinson, F. Wilczek, Phys. Rev. Lett. 95 (2005) 011303, (gr-qc/0502074); S. Iso, H. Umetsu, F. Wilczek, Phys. Rev. Lett. 96 (2006) 151302, (hep-th/0602146); R. Banerjee, S. Kulkarni, (arXiv: 0707.2449 [hep-th])] of Hawking radiation using anomalies is established
The N=1 effective action of F-theory compactifications
International Nuclear Information System (INIS)
Grimm, Thomas W.
2011-01-01
The four-dimensional N=1 effective action of F-theory compactified on a Calabi-Yau fourfold is studied by lifting a three-dimensional M-theory compactification. The lift is performed by using T-duality realized via a Legendre transform on the level of the effective action, and the application of vector-scalar duality in three dimensions. The leading order Kaehler potential and gauge-kinetic coupling functions are determined. In these compactifications two sources of gauge theories are present. Space-time filling non-Abelian seven-branes arise at the singularities of the elliptic fibration of the fourfold. Their couplings are included by resolving the singular fourfold. Generically a U(1) r gauge theory arises from the R-R bulk sector if the base of the elliptically fibered Calabi-Yau fourfold supports 2r harmonic three-forms. The gauge coupling functions depend holomorphically on the complex structure moduli of the fourfold, comprising closed and open string degrees of freedom. The four-dimensional electro-magnetic duality is studied in the three-dimensional effective theory obtained after M-theory compactification. A discussion of matter couplings transforming in the adjoint of the seven-brane gauge group is included.
Study of quality effects on radiobiological actions, 1
International Nuclear Information System (INIS)
Iwanami, Shigeru; Nakazawa, Keiji; Matsubayashi, Takashi; Hashimoto, Shozo.
1979-01-01
In order to interpret the quality effects of high LET radiation on the radiobiological actions, the target theory formulated by Oda on basis of the microdose concept introduced by Rossi has been developed to express intertrack effect (cumulative effect) and intratrack effect (non-cumulative effect) separately. Analysis for the dose-survival relation by this theory have been discussed with comparison of those of Rossi or Bender. If the target for the intertrack effect was the same one for the intratrack effect, it was found in this theory that the contribution of the intertrack effect for the cell lethality was larger than that of the intratrack effect in the case of high LET radiation as well as in that of low LET ones. The survival rates of Escherichia coli B/r and B sub(s-1) irradiated with heavy ions such as He, C, N and O at 4 MeV/a.m.u. and neutrons at 1, 2 and 5 MeV were calculated with this theory. The results were in reasonable agreement with experimental ones. (author)
[Hormonal (levonorgestrel) emergency contraception--effectiveness and mechanism of action].
Medard, Lech M; Ostrowska, Lucyna
2010-07-01
Periodic abstinence and coitus interruptus are the most popular methods of contraception in Poland. Recent studies have provided us with evidence that the so-called "menstrual calendar" may be much less effective than it was believed. In these circumstances, promotion and use of safe and truly effective contraceptives is very important for Polish women. Emergency contraception (EC) is a method which could be used even in cases when other contraception methods have failed. Mechanism of action of levonorgestrel used for EC and possible disturbances in the process of implantation of the blastocyst in the endometrium, remain the source of heated discussion among medical professionals. The latest publications provide us with evidence that the use of levonorgestrel in EC neither alters endometrial receptivity nor impedes implantation. Hormonal EC effectiveness is another hot topic of gynecological endocrinology and statistics. There is, however, no better, safer, and more ethically accepted method of preventing unwanted pregnancy for patients in need of postcoital contraception.
Effective action for the Regge processes in gravity
Energy Technology Data Exchange (ETDEWEB)
Lipatov, L.N. [Petersburg Nuclear Physics Institute, Gatchina, St. Petersburg (Russian Federation); Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik
2011-05-15
It is shown, that the effective action for the reggeized graviton interactions can be formulated in terms of the reggeon fields A{sup ++} and A{sup --} and the metric tensor g{sub {mu}}{sub {nu}} in such a way, that it is local in the rapidity space and has the property of general covariance. The corresponding effective currents j{sup -} and j{sup +} satisfy the Hamilton-Jacobi equation for a massless particle moving in the gravitational field. These currents are calculated explicitly for the shock wave-like fields and a variation principle for them is formulated. As an application, we reproduce the effective lagrangian for the multi-regge processes in gravity together with the graviton Regge trajectory in the leading logarithmic approximation with taking into account supersymmetric contributions. (orig.)
Immunoregulatory action of melatonin. The mechanism of action and the effect on inflammatory cells
Directory of Open Access Journals (Sweden)
Sylwia Mańka
2016-10-01
Full Text Available Literature data indicate a significant immunoregulatory role of melatonin. Melatonin exerts an effect directly affecting leucocytes bearing specific melatonin receptors or indirectly by means of melatonin regulating other hormones, opioids or cytokines. Despite numerous experiments, the influence of the hormone on the immune system is still controversial. Melatonin affects the immune response acting as both an activator and an inhibitor of the inflammatory process. The hormone acts as an “immunological buffer” activating impaired immunity in immunosuppression, chronic stress or old age as well as suppressing overreaction of the immune system. Melatonin mediates between neurohormonal and immune systems by means of the immune-pineal axis acting as a negative feedback mechanism. The axis connects development of the immune reaction with pineal activity and melatonin secretion induced by inflammatory mediators. The seasonal and circadian fluctuation of the melatonin level and the fluctuation related changes of the immune parameters can be responsible for some autoimmune and infectious diseases. In spite of that, there is a growing number of papers suggesting considerable therapeutic potential of melatonin in inflammatory disease treatment. This paper presents well-systematized information on the mechanism of melatonin action and its influence on cells involved in the inflammatory process – neutrophils and monocytes.
Zhao, Ke; Chen, Yu-Hsin; Yan, Wen-Jing; Fu, Xiaolan
2013-01-01
Binding effect refers to the perceptual attraction between an action and an outcome leading to a subjective compression of time. Most studies investigating binding effects exclusively employ the "pressing" action without exploring other types of actions. The present study addresses this issue by introducing another action, releasing action or the voluntary lifting of the finger/wrist, to investigate the differences between voluntary pressing and releasing actions. Results reveal that releasing actions led to robust yet short-lived temporal binding effects, whereas pressing condition had steady temporal binding effects up to super-seconds. The two actions also differ in sensitivity to changes in temporal contiguity and contingency, which could be attributed to the difference in awareness of action. Extending upon current models of "willed action," our results provide insights from a temporal point of view and support the concept of a dual system consisting of predictive motor control and top-down mechanisms.
Effective corrective actions to enhance operational safety of nuclear installations
International Nuclear Information System (INIS)
2005-07-01
The safe operation of nuclear power plants around the world and the prevention of incidents in these installations remain key concerns for the nuclear community. In this connection the feedback of operating experience plays a major role: every nuclear plant operator needs to have a system in place to identify and feed back the lessons learned from operating experience and to implement effective corrective actions to prevent safety events from reoccurring. An effective operating experience programme also includes a proactive approach that is aimed at preventing the first-time occurrence of safety events. In April 2003, the IAEA issued the PROSPER guidelines for nuclear installations to strengthen and enhance their own operating experience process and for self-assessment on the effectiveness of the feedback process. Subsequently, in the course of the Operational Safety Review Teams missions conducted by the IAEA that focused on the operational safety practices of nuclear power plants, the IAEA enhanced the review of the operating experience in nuclear power plants by implementing a new module that is derived from these guidelines. In order to highlight the effective implementation of the operating experience programme and to provide practical assistance in this area, the IAEA organized workshops and conferences to discuss recent trends in operating experience. The IAEA also performed assistance and review missions at plants and corporate organizations. The IAEA is further developing advice and assistance on operating experience feedback programmes and is reporting on good practices. The present publication is the outcome of two years of coordinated effort involving the participation of experts of nuclear organizations in several Member States. It provides information and good practices for successfully establishing an effective corrective actions programme. This publication forms part of a series that develops the principles set forth in these guidelines
Dignath, David; Janczyk, Markus
2017-09-01
According to the ideomotor principle, behavior is controlled via a retrieval of the sensory consequences that will follow from the respective movement ("action-effects"). These consequences include not only what will happen, but also when something will happen. In fact, recollecting the temporal duration between response and effect takes time and prolongs the initiation of the response. We investigated the associative structure of action-effect learning with delayed effects and asked whether participants acquire integrated action-time-effect episodes that comprise a compound of all three elements or whether they acquire separate traces that connect actions to the time until an effect occurs and actions to the effects that follow them. In three experiments, results showed that participants retrieve temporal intervals that follow from their actions even when the identity of the effect could not be learned. Furthermore, retrieval of temporal intervals in isolation was not inferior to retrieval of temporal intervals that were consistently followed by predictable action-effects. More specifically, when tested under extinction, retrieval of action-time and action-identity associations seems to compete against each other, similar to overshadowing effects reported for stimulus-response conditioning. Together, these results suggest that people anticipate when the consequences of their action will occur, independently from what the consequences will be.
Clemastine as Antimicrobial Agent: Effectiveness and Mechanism of Action
Directory of Open Access Journals (Sweden)
S.Fazli Bazaz
1991-07-01
Full Text Available In this investigation, the antimicrobial activity of Clemastine was studied.The Minimum Inhibitory Concentrations (MICs of this drug against some bacteria were determined using tube dilution method.To find out the bactericidal activity of Clemastine, the number of living bacteria in the presence of drug was counted by a culture method (pour plate method. Thereafter, the preservative effectiveness of Clemastine was studied in detail using standard method (USP 1985.The results show a good antibacterial but not antifungal activity."nIn considering the mechanism of action of Clemastine, it can be seen that the drug has some effect on cell membrane permeability and causes leakage of intracellular material including the K+ .Comparing the bactericidal results with the leakage of K+, shows that the leakage may be due to the bactericidal activity of the drug.
Brane classical and quantum cosmology from an effective action
International Nuclear Information System (INIS)
Seahra, Sanjeev S.; Sepangi, H.R.; Ponce de Leon, J.
2003-01-01
Motivated by the Randall-Sundrum braneworld scenario, we discuss the classical and quantum dynamics of a (d+1)-dimensional boundary wall between a pair of (d+2)-dimensional topological Schwarzschild-AdS black holes. We assume there are quite general--but not completely arbitrary--matter fields living on the boundary 'brane universe', and that its geometry is that of a Friedmann-Lemaitre-Robertson-Walker (FLRW) model. The effective action governing the model in the minisuperspace approximation is derived. We find that the presence of black hole horizons in the bulk gives rise to a complex action for certain classically allowed brane configurations, but that the imaginary contribution plays no role in the equations of motion. Classical and instanton brane trajectories are examined in general and for special cases, and we find a subset of configuration space that is not allowed at the classical or semiclassical level; this subset corresponds to spacelike branes carrying tachyonic matter. The Hamiltonization and Dirac quantization of the model is then performed for the general case; the latter involves the manipulation of the Hamiltonian constraint before it is transformed into an operator that annihilates physical state vectors. The ensuing covariant Wheeler-DeWitt equation is examined at the semiclassical level, and we consider the possible localization of the brane universe's wave function away from the cosmological singularity. This is easier to achieve for branes with low density and/or spherical spatial sections
Brane classical and quantum cosmology from an effective action
Seahra, Sanjeev S.; Sepangi, H. R.; Ponce de Leon, J.
2003-09-01
Motivated by the Randall-Sundrum braneworld scenario, we discuss the classical and quantum dynamics of a (d+1)-dimensional boundary wall between a pair of (d+2)-dimensional topological Schwarzschild-AdS black holes. We assume there are quite general—but not completely arbitrary—matter fields living on the boundary “brane universe,” and that its geometry is that of a Friedmann-Lemaître-Robertson-Walker (FLRW) model. The effective action governing the model in the minisuperspace approximation is derived. We find that the presence of black hole horizons in the bulk gives rise to a complex action for certain classically allowed brane configurations, but that the imaginary contribution plays no role in the equations of motion. Classical and instanton brane trajectories are examined in general and for special cases, and we find a subset of configuration space that is not allowed at the classical or semiclassical level; this subset corresponds to spacelike branes carrying tachyonic matter. The Hamiltonization and Dirac quantization of the model is then performed for the general case; the latter involves the manipulation of the Hamiltonian constraint before it is transformed into an operator that annihilates physical state vectors. The ensuing covariant Wheeler-DeWitt equation is examined at the semiclassical level, and we consider the possible localization of the brane universe’s wave function away from the cosmological singularity. This is easier to achieve for branes with low density and/or spherical spatial sections.
The effective action approach applied to nuclear matter (1)
International Nuclear Information System (INIS)
Tran Huu Phat; Nguyen Tuan Anh.
1996-11-01
Within the framework of the Walecka model (QHD-I) the application of the Cornwall-Jackiw-Tomboulis (CJT) effective action to nuclear matter is presented. The main feature is the treating of the meson condensates for the system of finite nuclear density. The system of couple Schwinger-Dyson (SD) equations is derived. It is shown that SD equations for sigma-omega mixings are absent in this formalism. Instead, the energy density of the nuclear ground state does explicitly contain the contributions from the ring diagrams, amongst others. In the bare-vertex approximation, the expression for energy density is written down for numerical computation in the next paper. (author). 14 refs, 3 figs
Zamolodchikov's c-theorem and string effective actions
International Nuclear Information System (INIS)
Mavromatos, N.E.; Miramontes, J.L.
1988-01-01
Zamolodchikov's c-theorem for 2D renormalisable field theories is presented in a way which allows for a straightforward application to the case of bosonic σ-models. As a consistency check in the latter case, the Curci-Paffuti relation is rederived. It is also shown that the 'metric' in coupling constant space in this case is a c-number function of the backgrounds. Attempts to derive off-shell functional relations between the Weyl anomaly coefficients and field variations of string effective actions, compatible with the c-theorem, are discussed by emphasising the necessity of performing explicit perturbative calculations in order to arrive at definite conclusions. Comments concerning the extension of the c-theorem to the case of supersymmetric and heterotic σ-models are also made. (orig.)
The effective action of a BPS Alice string
Energy Technology Data Exchange (ETDEWEB)
Chatterjee, Chandrasekhar; Nitta, Muneto [Keio University, Department of Physics, and Research and Education Center for Natural Sciences, Yokohama, Kanagawa (Japan)
2017-11-15
Recently a BPS Alice string has been found in a U(1) x SO(3) gauge theory coupled with three charged complex scalar fields in the triplet representation (in JHEP 1709:046 arXiv:1703.08971 [hep-th], 2017). It is a half BPS state preserving a half of the supercharges when embedded into a supersymmetric gauge theory. In this paper, we study zero modes of a BPS Alice string. After presenting U(1) and translational zero modes, we construct the effective action of these modes. In contrast to a previous analysis of the conventional Alice string for which only large distance behaviors are known, we can exactly perform a calculation in the full space thanks to the BPS properties. (orig.)
On non-BPS effective actions of string theory
Hatefi, Ehsan
2018-05-01
We discuss some physical prospective of the non-BPS effective actions of type IIA and IIB superstring theories. By dealing with all complete three and four point functions, including a closed Ramond-Ramond string (in terms of both its field strength and its potential), gauge (scalar) fields as well as a real tachyon and under symmetry structures, we find various restricted world volume and bulk Bianchi identities. The complete forms of the non-BPS scattering amplitudes including their Chan-Paton factors are elaborated. All the singularity structures of the non-BPS amplitudes, their all order α ' higher-derivative corrections, their contact terms and various modified Bianchi identities are derived. Finally, we show that scattering amplitudes computed in different super-ghost pictures are compatible when suitable Bianchi identities are imposed on the Ramond-Ramond fields. Moreover, we argue that the higher-derivative expansion in powers of the momenta of the tachyon is universal.
Geometric low-energy effective action in a doubled spacetime
Ma, Chen-Te; Pezzella, Franco
2018-05-01
The ten-dimensional supergravity theory is a geometric low-energy effective theory and the equations of motion for its fields can be obtained from string theory by computing β functions. With d compact dimensions, an O (d , d ; Z) geometric structure can be added to it giving the supergravity theory with T-duality manifest. In this paper, this is constructed through the use of a suitable star product whose role is the one to implement the weak constraint on the fields and the gauge parameters in order to have a closed gauge symmetry algebra. The consistency of the action here proposed is based on the orthogonality of the momenta associated with fields in their triple star products in the cubic terms defined for d ≥ 1. This orthogonality holds also for an arbitrary number of star products of fields for d = 1. Finally, we extend our analysis to the double sigma model, non-commutative geometry and open string theory.
Ward Identities for the 2PI effective action in QED
International Nuclear Information System (INIS)
Reinosa, Urko; Serreau, Julien
2007-01-01
We study the issue of symmetries and associated Ward-like identities in the context of two-particle-irreducible (2PI) functional techniques for abelian gauge theories. In the 2PI framework, the n-point proper vertices of the theory can be obtained in various different ways which, although equivalent in the exact theory, differ in general at finite approximation order. We derive generalized (2PI) Ward identities for these various n-point functions and show that such identities are exactly satisfied at any approximation order in 2PI QED. In particular, we show that 2PI-resummed vertex functions, i.e. field-derivatives of the so-called 2PI-resummed effective action, exactly satisfy standard Ward identities. We identify another set of n-point functions in the 2PI framework which exactly satisfy the standard Ward identities at any approximation order. These are obtained as field-derivatives of the two-point function φ, which defines the extremum of the 2PI effective action. We point out that the latter is not constrained by the underlying symmetry. As a consequence, the well-known fact that the corresponding gauge-field polarization tensor is not transverse in momentum space for generic approximations does not constitute a violation of (2PI) Ward identities. More generally, our analysis demonstrates that approximation schemes based on 2PI functional techniques respect all the Ward identities associated with the underlying abelian gauge symmetry. Our results apply to arbitrary linearly realized global symmetries as well
Influence of Action-Effect Associations Acquired by Ideomotor Learning on Imitation
Bunlon, Frédérique; Marshall, Peter J.; Quandt, Lorna C.; Bouquet, Cedric A.
2015-01-01
According to the ideomotor theory, actions are represented in terms of their perceptual effects, offering a solution for the correspondence problem of imitation (how to translate the observed action into a corresponding motor output). This effect-based coding of action is assumed to be acquired through action-effect learning. Accordingly, performing an action leads to the integration of the perceptual codes of the action effects with the motor commands that brought them about. While ideomotor theory is invoked to account for imitation, the influence of action-effect learning on imitative behavior remains unexplored. In two experiments, imitative performance was measured in a reaction time task following a phase of action-effect acquisition. During action-effect acquisition, participants freely executed a finger movement (index or little finger lifting), and then observed a similar (compatible learning) or a different (incompatible learning) movement. In Experiment 1, finger movements of left and right hands were presented as action-effects during acquisition. In Experiment 2, only right-hand finger movements were presented during action-effect acquisition and in the imitation task the observed hands were oriented orthogonally to participants’ hands in order to avoid spatial congruency effects. Experiments 1 and 2 showed that imitative performance was improved after compatible learning, compared to incompatible learning. In Experiment 2, although action-effect learning involved perception of finger movements of right hand only, imitative capabilities of right- and left-hand finger movements were equally affected. These results indicate that an observed movement stimulus processed as the effect of an action can later prime execution of that action, confirming the ideomotor approach to imitation. We further discuss these findings in relation to previous studies of action-effect learning and in the framework of current ideomotor approaches to imitation. PMID:25793755
Effects of aging on action-intentional programming.
Shoraka, Ali R; Otzel, Dana M; M Zilli, Eduardo; Finney, Glen R; Doty, Leilani; Falchook, Adam D; Heilman, Kenneth M
2018-03-01
Action-intentional programs control "when" we initiate, inhibit, continue, and stop motor actions. The purpose of this study was to learn if there are changes in the action-intentional system with healthy aging, and if these changes are asymmetrical (right versus left upper limb) or related to impaired interhemispheric communication. We administered tests of action-intention to 41 middle-aged and older adults (61.9 ± 12.3 years). Regression analyses revealed that older age predicted a decrement in performance for tests of crossed motor response inhibition as well as slower motor initiation with the left hand. Changes in action-intention with aging appear to be related to alterations of interhemispheric communication and/or age-related right hemisphere dysfunction; however, further research is needed to identify the mechanisms for age-related changes in the brain networks that mediate action-intention.
Ecological effects of contaminants and remedial actions in Bear Creek
Energy Technology Data Exchange (ETDEWEB)
Southworth, G.R.; Loar, J.M.; Ryon, M.G.; Smith, J.G.; Stewart, A.J. (Oak Ridge National Lab., TN (United States)); Burris, J.A. (C. E. Environmental, Inc., Tallahassee, FL (United States))
1992-01-01
Ecological studies of the Bear Creek watershed, which drains the area surrounding several Oak Ridge Y-12 Plant waste disposal facilities, were initiated in May 1984 and are continuing at present. These studies consisted of an initial, detailed characterization of the benthic invertebrate and fish communities in Bear Creek, and they were followed by a presently ongoing monitoring phase that involves reduced sampling intensities. The characterization phase utilized two approaches: (1) instream sampling of benthic invertebrate and fish communities in Bear Creek to identify spatial and temporal patterns in distribution and abundance and (2) laboratory bioassays on water samples from Bear Creek and selected tributaries to identify potential sources of toxicity to biota. The monitoring phase of the ecological program relates to the long-term goals of identifying and prioritizing contaminant sources and assessing the effectiveness of remedial actions. It continues activities of the characterization phase at less frequent intervals. The Bear Greek Valley is a watershed that drains the area surrounding several closed Oak Ridge Y-12 Plant waste disposal facilities. Past waste disposal practices in Bear Creek Valley resulted in contamination of Bear Creek and consequent ecological damage. Extensive remedial actions have been proposed at waste sites, and some of the have been implemented or are now underway. The proposed study plan consists of an initial, detailed characterization of the benthic invertebrate and fish communities in Bear Creek in the first year followed by a reduction in sampling intensity during the monitoring phase of the plan. The results of sampling conducted from May 1984 through early 1989 are presented in this report.
Scales, strategies and actions for effective energy planning: A review
International Nuclear Information System (INIS)
Pasimeni, Maria Rita; Petrosillo, Irene; Aretano, Roberta; Semeraro, Teodoro; De Marco, Antonella; Zaccarelli, Nicola; Zurlini, Giovanni
2014-01-01
This paper is a review of the most recent literature on the interaction between climate change, land-use and energy, based on the analysis of papers collected through the most relevant scientific literature databases. A total of 114 papers published between 2000 and 2011 were reviewed. The aims of this review are: in general (1) to identify the different research topics that have been developed related to the interaction between climate change, land-use and energy; more specifically, (2) to analyze what are the most suitable spatial and temporal scales of investigation to focus on for actions and strategies to reduce critical issues in the field of energy and environment; (3) to identify which actions and strategies are deemed as the most appropriate to mitigate critical issues in energy and environment; and given the research gaps found in the review, (4) to propose research recommendations in the context of effective climate-energy planning. We argue that there are certain gaps and needs for a “nested” environmental governance. It is necessary to understand how different environmental policies overlap and how they can be integrated in order to verify whether there are conflicting targets that may negate each other in the long term. - Highlights: • Energy production and consumption can directly or indirectly affect climate change. • Energy sector is influenced directly and indirectly by changes in climate conditions. • Energy sector and climate change affect and limit alternative uses of land, causing land-use changes. • The most suitable spatial scale for energy planning is the municipal level requiring short-term perspectives. • Several research recommendations to deal with the complexity of energy-land-use-climate change issue are proposed
Ecological effects of contaminants and remedial actions in Bear Creek
International Nuclear Information System (INIS)
Southworth, G.R.; Loar, J.M.; Ryon, M.G.; Smith, J.G.; Stewart, A.J.; Burris, J.A.
1992-01-01
Ecological studies of the Bear Creek watershed, which drains the area surrounding several Oak Ridge Y-12 Plant waste disposal facilities, were initiated in May 1984 and are continuing at present. These studies consisted of an initial, detailed characterization of the benthic invertebrate and fish communities in Bear Creek, and they were followed by a presently ongoing monitoring phase that involves reduced sampling intensities. The characterization phase utilized two approaches: (1) instream sampling of benthic invertebrate and fish communities in Bear Creek to identify spatial and temporal patterns in distribution and abundance and (2) laboratory bioassays on water samples from Bear Creek and selected tributaries to identify potential sources of toxicity to biota. The monitoring phase of the ecological program relates to the long-term goals of identifying and prioritizing contaminant sources and assessing the effectiveness of remedial actions. It continues activities of the characterization phase at less frequent intervals. The Bear Greek Valley is a watershed that drains the area surrounding several closed Oak Ridge Y-12 Plant waste disposal facilities. Past waste disposal practices in Bear Creek Valley resulted in contamination of Bear Creek and consequent ecological damage. Extensive remedial actions have been proposed at waste sites, and some of the have been implemented or are now underway. The proposed study plan consists of an initial, detailed characterization of the benthic invertebrate and fish communities in Bear Creek in the first year followed by a reduction in sampling intensity during the monitoring phase of the plan. The results of sampling conducted from May 1984 through early 1989 are presented in this report
Wong's equations and the small x effective action in QCD
Energy Technology Data Exchange (ETDEWEB)
Jalilian-Marian, Jamal; Jeon, Sangyong; Venugopalan, Raju
2000-07-13
We propose a new form for the small x effective action in QCD. This form of the effective action is motivated by Wong's equations for classical, colored particles in non-Abelian background fields. We show that the BFKL equation, which sums leading logarithms in x, is efficiently reproduced with this form of the action. We argue that this form of the action may be particularly useful in computing next-to-leading-order results in QCD at small x.
The relationship between action-effect monitoring and attention capture.
Kumar, Neeraj; Manjaly, Jaison A; Sunny, Meera Mary
2015-02-01
Many recent findings suggest that stimuli that are perceived to be the consequence of one's own actions are processed with priority. According to the preactivation account of intentional binding, predicted consequences are preactivated and hence receive a temporal advantage in processing. The implications of the preactivation account are important for theories of attention capture, as temporal advantage often translates to attention capture. Hence, action might modulate attention capture by feature singletons. Experiment 1 showed that a motion onset and color change captured attention only when it was preceded by an action. Experiment 2 showed that the capture occurs only with predictable, but not with unpredictable, consequences of action. Experiment 3 showed that even when half the display changed color at display transition, they were all prioritized. The results suggest that action modulates attentional control.
Non-abelian action of D0-branes from Matrix theory in the longitudinal 5-brane background
International Nuclear Information System (INIS)
Asano, Masako; Sekino, Yasuhiro
2002-01-01
We study one-loop effective action of Berkooz-Douglas Matrix theory and obtain non-abelian action of D0-branes in the background field produced by longitudinal 5-branes. Since these 5-branes do not have D0-brane charge and are not present in BFSS Matrix theory, our analysis provides an independent test for the coupling of D-branes to general weak backgrounds proposed by Taylor and Van Raamsdonk from the analysis of the BFSS model. The proposed couplings appear in the Berkooz-Douglas effective action precisely as expected, which suggests the consistency of the two matrix models. We also point out the existence of the terms which are not given by the symmetrized trace prescription in the Matrix theory effective action
Effects of action video game training on visual working memory.
Blacker, Kara J; Curby, Kim M; Klobusicky, Elizabeth; Chein, Jason M
2014-10-01
The ability to hold visual information in mind over a brief delay is critical for acquiring information and navigating a complex visual world. Despite the ubiquitous nature of visual working memory (VWM) in our everyday lives, this system is fundamentally limited in capacity. Therefore, the potential to improve VWM through training is a growing area of research. An emerging body of literature suggests that extensive experience playing action video games yields a myriad of perceptual and attentional benefits. Several lines of converging work suggest that action video game play may influence VWM as well. The current study utilized a training paradigm to examine whether action video games cause improvements to the quantity and/or the quality of information stored in VWM. The results suggest that VWM capacity, as measured by a change detection task, is increased after action video game training, as compared with training on a control game, and that some improvement to VWM precision occurs with action game training as well. However, these findings do not appear to extend to a complex span measure of VWM, which is often thought to tap into higher-order executive skills. The VWM improvements seen in individuals trained on an action video game cannot be accounted for by differences in motivation or engagement, differential expectations, or baseline differences in demographics as compared with the control group used. In sum, action video game training represents a potentially unique and engaging platform by which this severely capacity-limited VWM system might be enhanced.
Regulation of international energy markets: Economic effects of political actions
Shcherbakova, Anastasia V.
Recent increases in volatility of energy prices have led many governments to reevaluate their regard of national energy reserves and reconsider future exploration, production, and consumption patterns. The flurry of activity that has been generated by such price volatility has included large-scale nationalizations of energy sectors, unilateral renegotiations of foreign energy development contracts, and expropriations of resources from foreign energy firms on one hand, and on the other hand more rapid energy sector liberalization, intensified search for and development of renewable fuels and technologies, and development of incentives for increased energy efficiency and conservation. The aim of this dissertation is to examine and quantify the extent of positive and negative effects that have resulted from some of these activities. The first chapter focuses on quantifying the effect that nationalistic sentiment has had on economic attractiveness of energy sectors during the decade prior to the recent global economic crisis, as measured by foreign direct investment (FDI) inflows. Empirical results demonstrate that both political and economic conditions play an important role in investors' decisions. A combination of investment friendliness, corruption levels, and democracy all help to explain the trends in energy-sector investment levels over time in my sample countries, although differences in the types of corruption existing in these nations do not. Investment levels, in turn, appear to influence future levels of oil production, underscoring the significance of good investment policies for future success of energy sectors. Chapter two considers the response of energy stock prices to severe regulatory actions. It employs an event study framework to examine causal effects of critical informational announcements (i.e. events of expropriation and nationalization) on daily returns and cumulative losses in firm value of energy corporations. Results show that a firm
Dissociating action-effect activation and effect-based response selection.
Schwarz, Katharina A; Pfister, Roland; Wirth, Robert; Kunde, Wilfried
2018-05-25
Anticipated action effects have been shown to govern action selection and initiation, as described in ideomotor theory, and they have also been demonstrated to determine crosstalk between different tasks in multitasking studies. Such effect-based crosstalk was observed not only in a forward manner (with a first task influencing performance in a following second task) but also in a backward manner (the second task influencing the preceding first task), suggesting that action effect codes can become activated prior to a capacity-limited processing stage often denoted as response selection. The process of effect-based response production, by contrast, has been proposed to be capacity-limited. These observations jointly suggest that effect code activation can occur independently of effect-based response production, though this theoretical implication has not been tested directly at present. We tested this hypothesis by employing a dual-task set-up in which we manipulated the ease of effect-based response production (via response-effect compatibility) in an experimental design that allows for observing forward and backward crosstalk. We observed robust crosstalk effects and response-effect compatibility effects alike, but no interaction between both effects. These results indicate that effect activation can occur in parallel for several tasks, independently of effect-based response production, which is confined to one task at a time. Copyright © 2018 Elsevier B.V. All rights reserved.
Polyphenols: Extraction Methods, Antioxidative Action, Bioavailability and Anticarcinogenic Effects
Directory of Open Access Journals (Sweden)
Eva Brglez Mojzer
2016-07-01
Full Text Available Being secondary plant metabolites, polyphenols represent a large and diverse group of substances abundantly present in a majority of fruits, herbs and vegetables. The current contribution is focused on their bioavailability, antioxidative and anticarcinogenic properties. An overview of extraction methods is also given, with supercritical fluid extraction highlighted as a promising eco-friendly alternative providing exceptional separation and protection from degradation of unstable polyphenols. The protective role of polyphenols against reactive oxygen and nitrogen species, UV light, plant pathogens, parasites and predators results in several beneficial biological activities giving rise to prophylaxis or possibly even to a cure for several prevailing human diseases, especially various cancer types. Omnipresence, specificity of the response and the absence of or low toxicity are crucial advantages of polyphenols as anticancer agents. The main problem represents their low bioavailability and rapid metabolism. One of the promising solutions lies in nanoformulation of polyphenols that prevents their degradation and thus enables significantly higher concentrations to reach the target cells. Another, more practiced, solution is the use of mixtures of various polyphenols that bring synergistic effects, resulting in lowering of the required therapeutic dose and in multitargeted action. The combination of polyphenols with existing drugs and therapies also shows promising results and significantly reduces their toxicity.
Nonlocal effective actions in semiclassical gravity: Thermal effects in stationary geometries
Elías, M.; Mazzitelli, F. D.; Trombetta, L. G.
2017-11-01
We compute the gravitational effective action by integrating out quantum matter fields in a weak gravitational field, using the Schwinger-Keldysh (in-in) formalism. We pay particular attention to the role of the initial quantum state in the structure of the nonlocal terms in the effective action, with an eye to nonlinear completions of the theory that may be relevant in astrophysics and cosmology. In this first paper we consider a quantum scalar field in thermal equilibrium, in a stationary gravitational field. We obtain a covariant expression for the nonlocal effective action, which can be expressed in terms of the curvature tensor, the four-velocity of the thermal bath, and the local Tolman temperature. We discuss the connection between the results for ultrastatic and static metrics through conformal transformations, and the main features of the thermal corrections to the semiclassical Einstein equations.
Action Control: Independent Effects of Memory and Monocular Viewing on Reaching Accuracy
Westwood, D.A.; Robertson, C.; Heath, M.
2005-01-01
Evidence suggests that perceptual networks in the ventral visual pathway are necessary for action control when targets are viewed with only one eye, or when the target must be stored in memory. We tested whether memory-linked (i.e., open-loop versus memory-guided actions) and monocular-linked effects (i.e., binocular versus monocular actions) on…
International Nuclear Information System (INIS)
Koerner, J.G.
2006-11-01
We calculate the so-called loop-by-loop contributions to the next-to-next-to-leading order O(α 2 α 2 s ) radiative QCD corrections for the production of heavy quark pairs in the collisions of unpolarized on-shell photons. In particular, we present analytical results for the squared matrix elements that correspond to the product of the one-loop amplitudes. All results of the perturbative calculation are given in the dimensional regularization scheme. These results represent the Abelian part of the corresponding gluon-induced next-to-next-to-leading order cross section for heavy quark pair hadroproduction. (orig.)
Action-Effect Associations in Voluntary and Cued Task-Switching
Sommer, Angelika; Lukas, Sarah
2018-01-01
The literature of action control claims that humans control their actions in two ways. In the stimulus-based approach, actions are triggered by external stimuli. In the ideomotor approach, actions are elicited endogenously and controlled by the intended goal. In the current study, our purpose was to investigate whether these two action control modes affect task-switching differently. We combined a classical task-switching paradigm with action-effect learning. Both experiments consisted of two experimental phases: an acquisition phase, in which associations between task, response and subsequent action effects were learned and a test phase, in which the effects of these associations were tested on task performance by presenting the former action effects as preceding effects, prior to the task (called practiced effects). Subjects either chose freely between tasks (ideomotor action control mode) or they were cued as to which task to perform (sensorimotor action control mode). We aimed to replicate the consistency effect (i.e., task is chosen according to the practiced task-effect association) and non-reversal advantage (i.e., better task performance when the practiced effect matches the previously learned task-effect association). Our results suggest that participants acquired stable action-effect associations independently of the learning mode. The consistency effect (Experiment 1) could be shown, independent of the learning mode, but only on the response-level. The non-reversal advantage (Experiment 2) was only evident in the error rates and only for participants who had practiced in the ideomotor action control mode. PMID:29387027
Effects of navigated TMS on object and action naming
Directory of Open Access Journals (Sweden)
Julio Cesar Hernandez-Pavon
2014-09-01
Full Text Available Transcranial magnetic stimulation (TMS has been used to induce speech disturbances and to affect speech performance during different naming tasks. Lately, repetitive navigated TMS (nTMS has been used for non-invasive mapping of cortical speech-related areas. Different naming tasks may give different information that can be useful for presurgical evaluation. We studied the sensitivity of object and action naming tasks to nTMS and compared the distributions of cortical sites where nTMS produced naming errors. Eight healthy subjects named pictures of objects and actions during repetitive nTMS delivered to semi-random left-hemispheric sites. Subject-validated image stacks were obtained in the baseline naming of all pictures before nTMS. Thereafter, nTMS pulse trains were delivered while the subjects were naming the images of objects or actions. The sessions were video-recorded for offline analysis. Naming during nTMS was compared with the baseline performance. The nTMS-induced naming errors were categorized by error type and location. nTMS produced no-response errors, phonological paraphasias, and semantic paraphasias. In seven out of eight subjects, nTMS produced more errors during object than action naming. Both intrasubject and intersubject analysis showed that object naming was significantly more sensitive to nTMS. When the number of errors was compared according to a given area, nTMS to postcentral gyrus induced more errors during object than action naming. Object naming is apparently more easily disrupted by TMS than action naming. Different stimulus types can be useful for locating different aspects of speech functions. This provides new possibilities in both basic and clinical research of cortical speech representations.
22 CFR 161.12 - Environmental effects abroad of major departmental actions.
2010-04-01
... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Environmental effects abroad of major... Requirements of NEPA § 161.12 Environmental effects abroad of major departmental actions. Departmental officials shall analyze actions under their cognizance with due regard for the environmental effects in the...
Effectiveness of interim remedial actions at a radioactive waste facility
International Nuclear Information System (INIS)
Devgun, J.S.; Beskid, N.J.; Peterson, J.M.; Seay, W.M.; McNamee, E.
1989-01-01
Over the past eight years, several interim remedial actions have been taken at the Niagara Falls Storage Site (NFSS), primarily to reduce radon and gamma radiation exposures and to consolidate radioactive waste into a waste containment facility. Interim remedial actions have included capping of vents, sealing of pipes, relocation of the perimeter fence (to limit radon risk), transfer and consolidation of waste, upgrading of storage buildings, construction of a clay cutoff wall (to limit the potential groundwater transport of contaminants), treatment and release of contaminated water, interim use of a synthetic liner, and emplacement of an interim clay cap. An interim waste containment facility was completed in 1986. 6 refs., 3 figs
Vitamin D - new action mechanisms and effects | Haag | South ...
African Journals Online (AJOL)
The classic arena of vitamin D (cholecalciferol) action is the maintenance of calcium homeostasis. Intestinal ... Recently many other tissues have also joined the classic target organs of calcitriol, for example the pancreas, the immune system, the skin and the parathyroid gland, as well as an array of tumour"tissues. In these ...
Li, S N; Zhang, K Y
1992-11-01
Effects of dauricine (Dau) on the action potentials (AP), the slow action potentials (SAP), and the slow inward currents (Isi) of guinea pig ventricular papillary muscles were observed by means of intracellular microelectrode and single sucrose gap voltage clamp technique. In the early stage, Dau shortened action potential duration 100 (APD100) and effective refractory period (ERP) (ERP/APD ERP, and APD20, significantly decreased action potential amplitude (APA), maximum velocity (Vmax), and overshot (OS) (ERP/APD > 1; P SAP induced by isoprenaline (P < 0.01), and remarkably inhibited Isi (P < 0.01). The results suggested that Dau exerted an inhibitory effect on Na+, Ca2+, and K+ channels.
Energy Technology Data Exchange (ETDEWEB)
Podstavkova, S; Vlcek, D; Dubovsky, J [Komenskeho Univ., Bratislava (Czechoslovakia). Prirodovedecka Fakulta
1978-01-01
The effect of UV radiation and UV radiation combined with alkylnitrosourea derivatives (N-methyl-N-nitrosourea and N-ethyl-N-nitrosourea) was observed on survival of cells of the algae Chlamydomonas reinhardtii. In particular, single parts were evaluated of the overall lethal effect - dying of cells before division and dying of cells after division. It was found that the combined action of low doses of UV radiation and alkylnitrosoureas result in a pronounced protective effect which manifests itself by a higher frequency of surviving cells than was that effected by the action of alkylnitrosoureas alone. As a result of combined action with higher doses of UV radiation this effect is lost, and the resultant values will come close to the theoretically anticipated values. This gradual transition from a protective to an additive effect mainly manifests itself by changes in the proportion of cells dying before division.
Response selection difficulty modulates the behavioral impact of rapidly learnt action effects.
Directory of Open Access Journals (Sweden)
Uta eWolfensteller
2014-12-01
Full Text Available It is well established that we can pick up action effect associations when acting in a free-choice intentional mode. However, it is less clear whether and when action effect associations are learnt and actually affect behavior if we are acting in a forced-choice mode, applying a specific stimulus-response (S-R rule. In the present study, we investigated whether response selection difficulty imposed by S-R rules influences the initial rapid learning and the behavioral expression of previously learnt but weakly practiced action effect associations when those are re-activated by effect exposure. Experiment 1 showed that the rapid acquisition of action effect associations is not directly influenced by response selection difficulty. By contrast, the behavioral expression of re-activated action effect associations is prevented when actions are directly activated by highly over-learnt response cues and thus response selection difficulty is low. However, all three experiments showed that if response selection difficulty is sufficiently high during re-activation, the same action effect associations do influence behavior. Experiment 2 and 3 revealed that the effect of response selection difficulty cannot be fully reduced to giving action effects more time to prime an action, but seems to reflect competition during response selection. Finally, the present data suggest that when multiple novel rules are rapidly learnt in succession, which requires a lot of flexibility, action effect associations continue to influence behavior only if response selection difficulty is sufficiently high. Thus, response selection difficulty might modulate the impact of experiencing multiple learning episodes on action effect expression and learning, possibly via inducing different strategies.
Long-term and short-term action-effect links and their impact on effect monitoring.
Wirth, Robert; Steinhauser, Robert; Janczyk, Markus; Steinhauser, Marco; Kunde, Wilfried
2018-04-23
People aim to produce effects in the environment, and according to ideomotor theory, actions are selected and executed via anticipations of their effects. Further, to ensure that an action has been successful and an effect has been realized, we must be able to monitor the consequences of our actions. However, action-effect links might vary between situations, some might apply for a majority of situations, while others might only apply to special occasions. With a combination of behavioral and electrophysiological markers, we show that monitoring of self-produced action effects interferes with other tasks, and that the length of effect monitoring is determined by both, long-term action-effect links that hold for most situations, and short-term action-effect links that emerge from a current setting. Effect monitoring is fast and frugal when these action-effect links allow for valid anticipation of action effects, but otherwise effect monitoring takes longer and delays a subsequent task. Specific influences of long-term and short-term links on the P1/N1 and P3a further allow to dissect the temporal dynamics of when these links interact for the purpose of effect monitoring. (PsycINFO Database Record (c) 2018 APA, all rights reserved).
Effects of context on visuomotor interference depends on the perspective of observed actions.
Directory of Open Access Journals (Sweden)
Marta Bortoletto
Full Text Available Visuomotor interference occurs when the execution of an action is facilitated by the concurrent observation of the same action and hindered by the concurrent observation of a different action. There is evidence that visuomotor interference can be modulated top-down by higher cognitive functions, depending on whether own performed actions or observed actions are selectively attended. Here, we studied whether these effects of cognitive context on visuomotor interference are also dependent on the point-of-view of the observed action. We employed a delayed go/no-go task known to induce visuomotor interference. Static images of hand gestures in either egocentric or allocentric perspective were presented as "go" stimuli after participants were pre-cued to prepare either a matching (congruent or non-matching (incongruent action. Participants performed this task in two different cognitive contexts: In one, they focused on the visual image of the hand gesture shown as the go stimulus (image context, whereas in the other they focused on the hand gesture they performed (action context. We analyzed reaction times to initiate the prepared action upon presentation of the gesture image and found evidence of visuomotor interference in both contexts and for both perspectives. Strikingly, results show that the effect of cognitive context on visuomotor interference also depends on the perspective of observed actions. When focusing on own-actions, visuomotor interference was significantly less for gesture images in allocentric perspective than in egocentric perspective; when focusing on observed actions, visuomotor interference was present regardless of the perspective of the gesture image. Overall these data suggest that visuomotor interference may be modulated by higher cognitive processes, so that when we are specifically attending to our own actions, images depicting others' actions (allocentric perspective have much less interference on our own actions.
Spatio-temporal dynamics of action-effect associations in oculomotor control.
Riechelmann, Eva; Pieczykolan, Aleksandra; Horstmann, Gernot; Herwig, Arvid; Huestegge, Lynn
2017-10-01
While there is ample evidence that actions are guided by anticipating their effects (ideomotor control) in the manual domain, much less is known about the underlying characteristics and dynamics of effect-based oculomotor control. Here, we address three open issues. 1) Is action-effect anticipation in oculomotor control reflected in corresponding spatial saccade characteristics in inanimate environments? 2) Does the previously reported dependency of action latency on the temporal effect delay (action-effect interval) also occur in the oculomotor domain? 3) Which temporal effect delay is optimally suited to develop strong action-effect associations over time in the oculomotor domain? Participants executed left or right free-choice saccades to peripheral traffic lights, causing an (immediate or delayed) action-contingent light switch in the upper vs. lower part of the traffic light. Results indicated that saccades were spatially shifted toward the location of the upcoming change, indicating anticipation of the effect (location). Saccade latency was affected by effect delay, suggesting that corresponding time information is integrated into event representations. Finally, delayed (vs. immediate) effects were more effective in strengthening action-effect associations over the course of the experiment, likely due to greater saliency of perceptual changes occurring during target fixation as opposed to changes during saccades (saccadic suppression). Overall, basic principles underlying ideomotor control appear to generalize to the oculomotor domain. Copyright © 2017 Elsevier B.V. All rights reserved.
The Process’s Effectiveness in Popular Actions
Alencar, Rafael Vieira de; Albuquerque, Felipe Braga
2016-01-01
The aim of this work the study of the limits and possibilities of the known " general power of realization of judicial protection ". Concomitantly were delineated the structural goals of executory judge's powers, notably with the aim of establishing a study related to the procedure of displaying documents in popular action, the application of a daily fine for noncompliance and the presumption of veracity of the facts narrated in the popular original. As regards the methodology, it has been ca...
Kim, Ziyon; Óturai, Gabriella; Király, Ildikó; Knopf, Monika
2015-11-01
This study aimed to systematically investigate 18-month-old infants' imitation of object-related actions compared to motorically similar gestures. An additional goal of the study was to examine the role of action effects on infants' imitation of target actions. One group of infants (n=17) observed object-related actions and gestures leading to salient effects (sounds or visual resp. social effects), and the other group (n=16) watched the same actions without effects. Furthermore, this study examined whether infants show a consistent imitation ability for object-related actions and gestures. First, the present study showed that 18-month-old infants imitated object-related actions more frequently than gestures. Second, the presence of an effect significantly increased the imitation rate of object-related actions; however, this difference was not found for gestures. Third, indications for a general imitation ability were found as results on an individual level showed that object-related action imitation significantly correlated with gesture imitation. Implications of the results for theory and future studies are discussed with a focus on the role of objects and effects in 18-month-old infants' action imitation. Copyright © 2015 Elsevier Inc. All rights reserved.
The spillover effects of affirmative action on competitiveness and unethical behavior
DEFF Research Database (Denmark)
Gupta, Nabanita Datta; Banerjee, Ritwik; Villeval, Marie Claire
2018-01-01
We conduct an artefactual field experiment to examine various spillover effects of Affirmative Action policies in the context of castes in India. We test a) if individuals who enter tournaments in the presence of an Affirmative Action policy remain competitive after the policy has been removed...... find no spillover effect on confidence and competitiveness once Affirmative Action is withdrawn. Furthermore, the discrimination by the dominant category against the backward category is not significantly aggravated by Affirmative Action, except when individuals learn that they have lost the previous...
The Spillover Effects of Affirmative Action on Competitiveness and Unethical Behavior
DEFF Research Database (Denmark)
Banerjee, Ritwik; Gupta, Nabanita Datta; Villeval, Marie Claire
We conduct an artefactual field experiment to examine various spillover effects of Affirmative Action policies in the context of castes in India. We test a) if individuals who compete in the presence of Affirmative Action policies remain competitive in the same proportion after the policy has been...... frequently a tournament payment scheme. However, we find no spillover effect on confidence and competitiveness once Affirmative Action is withdrawn: any lower caste’s gain in competitiveness due to the policy is then entirely wiped out. Furthermore, the strong existing bias of the dominant caste against...... the lower caste is not significantly aggravated by Affirmative Action....
Making connections to translate climate research into effective action
Evans, K. J.; Niepold, F., III; Pierce, L.
2016-12-01
Climate change is strongly apparent at many scales and facets of the Earth system including glacier retreat, increased ocean acidity, altered meteorological patterns, and changing ecosystems. There is general recognition that a more strategic and coordinated response is needed to ameliorate these impacts on communities and to limit the global temperature increase to 1.5°C imposed by the 2015 Paris agreement. However, concrete plans to achieve these goals require actionable and specific guidance from the scientific community that is targeted for specific stakeholder groups within government agencies, industry, and individuals, while also supporting decision-makers plans and policies. This guidance depends on scientific advances that establish quantified predictions and minimize the levels of uncertainty. Although, these advances are ongoing; the decision maker, civil society organizations, and business and investor communities are not waiting for perfection. The urgency of taking action now has brought new approaches to the fore that try to bring the best available science into the business and decision making process. Combining a breadth of expertise, we highlight the specific transmission pathways of information needed for stakeholders, and it spans initial data collection and climate model construction, experimentation, analysis, synthesis of results, education, to government, communities, and business planning to reduce impacts and minimize additional human-caused contributions. We propose a multi-pathway relay along these paths. In one direction we encourage scientists to provide accessible and useable summary results with uncertainties to educators and stakeholders, who in turn need to collate results in a manner that enables interested parties to identify their specific mitigation action. In the other direction, stakeholders and shareholders are already requesting more comprehensive verification, validation, and active linkages to the way in which
Biological actions and effects of low-frequency fields
International Nuclear Information System (INIS)
Brix, J.
1993-01-01
Cell culture studies have shown that low-frequency electromagnetic fields may affect cell behaviour. The fact that the corresponding field strengths are too weak to affect membrane potential, suggests that these fields trigger enzymatic reactions at the outer face of the membrane, i.e. cell-intrinsic reaction cascades and a biological modification of the affected biological system take place. These are working models and hypotheses which need to substantiated by further studies in this field. Epidemiological studies suggest that electromagnetic fields influence cancer development in man. However there is no action model indicating exposure to fields to be a genotoxic agent possible triggering a direct genetic modification which precludesr any initialization. (orig.) [de
System markets: Indirect network effects in action, or inaction?
J.L.G. Binken (Jeroen)
2010-01-01
textabstractIn this dissertation, I empirically examine system markets up close. More specifically I examine indirect network effects, both demand-side and supply-side indirect network effects. Indirect network effects are the source of positive feedback in system markets, or so network effect
Effects of Affordance Perception on the Initiation and Actualization of Action
Smith, Joanne; Pepping, Gert-Jan
2010-01-01
Studies have shown information specifying some affordances may be faster or easier to perceive than others. This article investigates the effect of affordance perception on the time taken to initiate and perform an action. In particular it focuses on how action timing varies as a function of a
The Effect of Rapacuronium or Succinylcholine on the Duration of Action of Rocuronium
2001-10-01
THESIS APPROVAL FORM THE EFFECT OF RAPACURONIUM OR SUCCINYLCHOLINE ON THE DURATION OF ACTION OF ROCURONIUM Rachael Fontanilla, Capt...on the Duration of Action of Rocuronium ” beyond brief excerpts is with the permission of the copyright owner, and will save and hold harmless...side effects. Non-depolarizing neuromuscular blocking agents achieve the same efficacy as succinylcholine without the adverse effects. Rocuronium , an
High-energy effective action from scattering of QCD shock waves
Energy Technology Data Exchange (ETDEWEB)
Ian Balitsky
2005-07-01
At high energies, the relevant degrees of freedom are Wilson lines - infinite gauge links ordered along straight lines collinear to the velocities of colliding particles. The effective action for these Wilson lines is determined by the scattering of QCD shock waves. I develop the symmetric expansion of the effective action in powers of strength of one of the shock waves and calculate the leading term of the series. The corresponding first-order effective action, symmetric with respect to projectile and target, includes both up and down fan diagrams and pomeron loops.
The effects of an action video game on visual and affective information processing.
Bailey, Kira; West, Robert
2013-04-04
Playing action video games can have beneficial effects on visuospatial cognition and negative effects on social information processing. However, these two effects have not been demonstrated in the same individuals in a single study. The current study used event-related brain potentials (ERPs) to examine the effects of playing an action or non-action video game on the processing of emotion in facial expression. The data revealed that 10h of playing an action or non-action video game had differential effects on the ERPs relative to a no-contact control group. Playing an action game resulted in two effects: one that reflected an increase in the amplitude of the ERPs following training over the right frontal and posterior regions that was similar for angry, happy, and neutral faces; and one that reflected a reduction in the allocation of attention to happy faces. In contrast, playing a non-action game resulted in changes in slow wave activity over the central-parietal and frontal regions that were greater for targets (i.e., angry and happy faces) than for non-targets (i.e., neutral faces). These data demonstrate that the contrasting effects of action video games on visuospatial and emotion processing occur in the same individuals following the same level of gaming experience. This observation leads to the suggestion that caution should be exercised when using action video games to modify visual processing, as this experience could also have unintended effects on emotion processing. Published by Elsevier B.V.
System markets: Indirect network effects in action, or inaction?
Binken, Jeroen
2010-01-01
textabstractIn this dissertation, I empirically examine system markets up close. More specifically I examine indirect network effects, both demand-side and supply-side indirect network effects. Indirect network effects are the source of positive feedback in system markets, or so network effect theory tells us. Systems are composed of complementary and interdependent products, such as hardware and software. For instance, a video game system is composed of the video game console, on the one han...
Directory of Open Access Journals (Sweden)
Daniel L Eaves
Full Text Available We demonstrate that observation of everyday rhythmical actions biases subsequent motor execution of the same and of different actions, using a paradigm where the observed actions were irrelevant for action execution. The cycle time of the distractor actions was subtly manipulated across trials, and the cycle time of motor responses served as the main dependent measure. Although distractor frequencies reliably biased response cycle times, this imitation bias was only a small fraction of the modulations in distractor speed, as well as of the modulations produced when participants intentionally imitated the observed rhythms. Importantly, this bias was not only present for compatible actions, but was also found, though numerically reduced, when distractor and executed actions were different (e.g., tooth brushing vs. window wiping, or when the dominant plane of movement was different (horizontal vs. vertical. In addition, these effects were equally pronounced for execution at 0, 4, and 8 s after action observation, a finding that contrasts with the more short-lived effects reported in earlier studies. The imitation bias was also unaffected when vision of the hand was occluded during execution, indicating that this effect most likely resulted from visuomotor interactions during distractor observation, rather than from visual monitoring and guidance during execution. Finally, when the distractor was incompatible in both dimensions (action type and plane the imitation bias was not reduced further, in an additive way, relative to the single-incompatible conditions. This points to a mechanism whereby the observed action's impact on motor processing is generally reduced whenever this is not useful for motor planning. We interpret these findings in the framework of biased competition, where intended and distractor actions can be represented as competing and quasi-encapsulated sensorimotor streams.
Action potential influences spatial perception: Evidence for genuine top-down effects on perception.
Witt, Jessica K
2017-08-01
The action-specific account of spatial perception asserts that a perceiver's ability to perform an action, such as hitting a softball or walking up a hill, impacts the visual perception of the target object. Although much evidence is consistent with this claim, the evidence has been challenged as to whether perception is truly impacted, as opposed to the responses themselves. These challenges have recently been organized as six pitfalls that provide a framework with which to evaluate the empirical evidence. Four case studies of action-specific effects are offered as evidence that meets the framework's high bar, and thus that demonstrates genuine perceptual effects. That action influences spatial perception is evidence that perceptual and action-related processes are intricately and bidirectionally linked.
The effects of familiarity on thought--action fusion.
Berman, Noah C; Wheaton, Michael G; Fabricant, Laura E; Jacobson, Spenser R; Abramowitz, Jonathan S
2011-10-01
The present study examined whether beliefs about the importance of thoughts (i.e., thought--action fusion; TAF) are related to the target subject of the negative thought. One hundred and seven undergraduate students were randomly assigned to imagine either a beloved relative or a stranger being diagnosed with cancer and provided in vivo ratings of anxiety, likelihood, moral wrongness, urge to neutralize, and how upsetting the event would be if it occurred. Results indicated that thinking of a relative being diagnosed with cancer provoked more distress, urges to neutralize, and higher estimates of likelihood, as well greater use of mental neutralizing behaviors, compared to thinking of a stranger. Contrary to our prediction, the groups did not differ in their ratings of the moral wrongness. These findings broadly support the assertion that the more personally significant a negative intrusive thought, the more it will provoke distress and urges to neutralize. Results are discussed in terms of the cognitive model of obsessions and clinical implications are addressed. Copyright © 2011 Elsevier Ltd. All rights reserved.
Chiral effective potential in N = {1/2} non-commutative Wess-Zumino model
International Nuclear Information System (INIS)
Banin, A.T.; Buchbinder, I.L.; Pletnev, N.G.
2004-01-01
We study a structure of holomorphic quantum contributions to the effective action for N = {1/2} noncommutative Wess-Zumino model. Using the symbol operator techniques we present the one-loop chiral effective potential in a form of integral over proper time of the appropriate heat kernel. We prove that this kernel can be exactly found. As a result we obtain the exact integral representation of the one-loop effective potential. Also we study the expansion of the effective potential in a series in powers of the chiral superfield φ and derivative D 2 φ and construct a procedure for systematic calculation of the coefficients in the series. We show that all terms in the series without derivatives can be summed up in an explicit form. (author)
Action time effect of lime on its depressive ability for pyrite
Institute of Scientific and Technical Information of China (English)
Tichang Sun
2004-01-01
Two sample groups of bulk concentrates consisting mainly of pyrite and chalcopyrite from Daye and Chenghchao Mines in Hubei Province of China were used to investigate the effect of the action time of lime on its depressive ability for pyrite. The experimental results conducted with different samples and collectors showed that the action time between lime and pyrite markedly influences the depressive ability of lime. The depressive ability of lime increased with the action time increasing. It was also proved that the depressive results obtained at a large lime dosage after a shorter action time are similar to those obtained at a small lime dosage after a longer action time. The increase of depressive ability of lime after a longer action time is because that there are different mechanisms in different action time. The composition on the surface of pyrite acted for different time with lime was studied by using ESCA (Electron Spectroscopic Chemical Analysis). The results showed that iron hydroxide and calcium sulphate formed on the pyrite surface at the presence of lime in the pulp but the amounts of iron hydroxide and calcium sulphate were different at different action time. At the beginning action time the compound formed on the pyrite surface was mainly calcium sulphate and almost no iron hydroxide formed; but with the action time increasing, iron hydroxide formed. The longer the action time, the more iron hydroxide and the less calcium sulphate formed. It was considered that the stronger depressive ability of lime after a longer action time is because more iron hydroxide forms on the pyrite surface.
Automatic imitation effects are influenced by experience of synchronous action in children.
O'Sullivan, Eoin P; Bijvoet-van den Berg, Simone; Caldwell, Christine A
2018-07-01
By their fourth year of life, children are expert imitators, but it is unclear how this ability develops. One approach suggests that certain types of experience might forge associations between the sensory and motor representations of an action that may facilitate imitation at a later time. Sensorimotor experience of this sort may occur when an infant's action is imitated by a caregiver or when socially synchronous action occurs. This learning approach, therefore, predicts that the strength of sensory-motor associations should depend on the frequency and quality of previous experience. Here, we tested this prediction by examining automatic imitation, that is, the tendency of an action stimulus to facilitate the performance of that action and interfere with the performance of an incompatible action. We required children (aged between 3 years 8 months and 7 years 11 months) to respond to actions performed by an experimenter (e.g., two hands clapping) with both compatible actions (i.e., two hands clapping) and incompatible actions (i.e., two hands waving) at different stages in the experimental procedure. As predicted by a learning account, actions thought to be performed in synchrony (i.e., clapping/waving) produced stronger automatic imitation effects when compared with actions where previous sensorimotor experience is likely to be more limited (e.g., pointing/hand closing). Furthermore, these automatic imitation effects were not found to vary with age, with both compatible and incompatible responses quickening with age. These findings suggest a role for sensorimotor experience in the development of imitative ability. Copyright © 2018 Elsevier Inc. All rights reserved.
2013-03-05
In 2007, the Federal Railroad Administration (FRA) launched : C3RS, the Confidential Close Call Reporting System, as a : demonstration project to learn how to facilitate the effective : reporting and implementation of corrective actions, and assess t...
Fight against the greenhouse effect. From the local to the international action
International Nuclear Information System (INIS)
Mousel, M.
2002-01-01
In the fight against the greenhouse gases emissions, the local government are directly concerned. This sheet aims to explain the greenhouse effect, the kyoto protocol, the french national policy and to orientate the local actions. (A.L.B.)
The Effects of Motoric Action and Organization on Children's Memory.
Heindel, Patricia; Kose, Gary
1990-01-01
Two experiments examined preschool, first, and third grade students for the effects of motoric activities on memory performance. Findings for the first experiment revealed that, although organizational differences affected memory performance, the drawing of configurations enhanced the effect of unitary organization. In the second experiment,…
Biological effects under combined action of radiation and chemical factors
International Nuclear Information System (INIS)
Malenchenko, A.F.
1990-01-01
The paper considers the manifoild factors of environmental pollution effect upon living organisms and their possible response manifested in additivity, synergism and anthogonism. Consideration is also given to the possible practical measures for improving ecological situation and decreasing the risk of anthropogenesis negative after-effects
Exact CTP renormalization group equation for the coarse-grained effective action
International Nuclear Information System (INIS)
Dalvit, D.A.; Mazzitelli, F.D.
1996-01-01
We consider a scalar field theory in Minkowski spacetime and define a coarse-grained closed time path (CTP) effective action by integrating quantum fluctuations of wavelengths shorter than a critical value. We derive an exact CTP renormalization group equation for the dependence of the effective action on the coarse-graining scale. We solve this equation using a derivative expansion approach. Explicit calculation is performed for the λφ 4 theory. We discuss the relevance of the CTP average action in the study of nonequilibrium aspects of phase transitions in quantum field theory. copyright 1996 The American Physical Society
Effect of action verbs on the performance of a complex movement.
Directory of Open Access Journals (Sweden)
Tahar Rabahi
Full Text Available The interaction between language and motor action has been approached by studying the effect of action verbs, kinaesthetic imagery and mental subtraction upon the performance of a complex movement, the squat vertical jump (SVJ. The time of flight gave the value of the height of the SVJ and was measured with an Optojump® and a Myotest® apparatuses. The results obtained by the effects of the cognitive stimuli showed a statistically significant improvement of the SVJ performance after either loudly or silently pronouncing, hearing or reading the verb saute (jump in French language. Action verbs specific for other motor actions (pince = pinch, lèche = lick or non-specific (bouge = move showed no or little effect. A meaningless verb for the French subjects (tiáo = jump in Chinese showed no effect as did rêve (dream, tombe (fall and stop. The verb gagne (win improved significantly the SVJ height, as did its antonym perds (lose suggesting a possible influence of affects in the subjects' performance. The effect of the specific action verb jump upon the heights of SVJ was similar to that obtained after kinaesthetic imagery and after mental subtraction of two digits numbers from three digits ones; possibly, in the latter, because of the intervention of language in calculus. It appears that the effects of the specific action verb jump did seem effective but not totally exclusive for the enhancement of the SVJ performance. The results imply an interaction among language and motor brain areas in the performance of a complex movement resulting in a clear specificity of the corresponding action verb. The effect upon performance may probably be influenced by the subjects' intention, increased attention and emotion produced by cognitive stimuli among which action verbs.
Eaves, Daniel L.; Turgeon, Martine; Vogt, Stefan
2012-01-01
We demonstrate that observation of everyday rhythmical actions biases subsequent motor execution of the same and of different actions, using a paradigm where the observed actions were irrelevant for action execution. The cycle time of the distractor actions was subtly manipulated across trials, and the cycle time of motor responses served as the main dependent measure. Although distractor frequencies reliably biased response cycle times, this imitation bias was only a small fraction of the modulations in distractor speed, as well as of the modulations produced when participants intentionally imitated the observed rhythms. Importantly, this bias was not only present for compatible actions, but was also found, though numerically reduced, when distractor and executed actions were different (e.g., tooth brushing vs. window wiping), or when the dominant plane of movement was different (horizontal vs. vertical). In addition, these effects were equally pronounced for execution at 0, 4, and 8 s after action observation, a finding that contrasts with the more short-lived effects reported in earlier studies. The imitation bias was also unaffected when vision of the hand was occluded during execution, indicating that this effect most likely resulted from visuomotor interactions during distractor observation, rather than from visual monitoring and guidance during execution. Finally, when the distractor was incompatible in both dimensions (action type and plane) the imitation bias was not reduced further, in an additive way, relative to the single-incompatible conditions. This points to a mechanism whereby the observed action’s impact on motor processing is generally reduced whenever this is not useful for motor planning. We interpret these findings in the framework of biased competition, where intended and distractor actions can be represented as competing and quasi-encapsulated sensorimotor streams. PMID:23071623
Directory of Open Access Journals (Sweden)
Behrooz Jamali
2018-09-01
Full Text Available Created opportunities are refered as the opportunities in which none of the supply and demand parties exists clearly and obviously one or both of them must be created. Therefore, several economic inventions should take place in marketing, franchising, etc. so that opportunity can be created. This perception of opportunity deals with the creation of new markets. In the meantime, identifying some entrepreneurial actions influencing on the creation of entrepreneurial opportunities can provide backgrounds for the formation and empowering the opportunity creation. In this paper, some basic ideas about the creation of entrepreneurial opportunities and the evolution of opportunity creation theories are examined. Then effective actions on the opportunity creation are identified. Finally, the structure of the investigated actions is examined using the DEMATLE Method. The results which were according to the opinions of 15 experts of entrepreneurship showed that leadership, decision making, and strategy actions influence other entrepreneurial actions.
World-volume effective action of exotic five-brane in M-theory
International Nuclear Information System (INIS)
Kimura, Tetsuji; Sasaki, Shin; Yata, Masaya
2016-01-01
We study the world-volume effective action of an exotic five-brane, known as the M-theory 5"3-brane (M5"3-brane) in eleven dimensions. The supermultiplet of the world-volume theory is the N=(2,0) tensor multiplet in six dimensions. The world-volume action contains three Killing vectors k̂_I_̂"M (Î=1,2,3) associated with the U(1)"3 isometry. We find the effective T-duality rule for the eleven-dimensional backgrounds that transforms the M5-brane effective action to that of the M5"3-brane. We also show that our action provides the source term for the M5"3-brane geometry in eleven-dimensional supergravity.
World-volume effective action of exotic five-brane in M-theory
Energy Technology Data Exchange (ETDEWEB)
Kimura, Tetsuji [Research and Education Center for Natural Sciences, Keio University, Hiyoshi 4-1-1, Yokohama, Kanagawa 223-8521 (Japan); Department of Physics, Tokyo Institute of Technology,Tokyo 152-8551 (Japan); Sasaki, Shin [Department of Physics, Kitasato University,Sagamihara 252-0373 (Japan); Yata, Masaya [Department of Physics, National University of Singapore,2, Science Drive 3, Singapore 117542 (Singapore)
2016-02-25
We study the world-volume effective action of an exotic five-brane, known as the M-theory 5{sup 3}-brane (M5{sup 3}-brane) in eleven dimensions. The supermultiplet of the world-volume theory is the N=(2,0) tensor multiplet in six dimensions. The world-volume action contains three Killing vectors k̂{sub Î}{sup M} (Î=1,2,3) associated with the U(1){sup 3} isometry. We find the effective T-duality rule for the eleven-dimensional backgrounds that transforms the M5-brane effective action to that of the M5{sup 3}-brane. We also show that our action provides the source term for the M5{sup 3}-brane geometry in eleven-dimensional supergravity.
[The effect of food intake on drug action].
Pletscher, W; Peretti, E
1990-01-01
Interactions between medicaments and food are only incompletely documented--despite their frequent occurrence. Food can influence the effect of medicaments in a variety of ways: the effect of the medicament can be delayed or weakened; in some cases the effect may also be increased. The interactions between the kinetics of medicaments and food are described in the present survey. The absorption conditions in the stomach and small intestine are influenced physiologically and chemically by food. In very rare cases the elimination of active ingredients too can be modified by the quality and quantity of the food. Detailed knowledge about the physical-chemical properties of the medicaments used help to optimize the pharmacotherapy in the individual case. For the patient, the easiest suggestion to follow would be to take the medicaments with plenty of water and always at the same time.
The Greenhouse effect: from research to political action
International Nuclear Information System (INIS)
Bernard, A.; Charmant, A.; Ladoux, N.; Vielle, M.
1992-01-01
What would be the ecological and socio-economic consequences of the warming of the planet Earth. The greenhouse effect is better defined today, but evaluating the dangers is still a risky business which demands extreme caution. The study recapitulates the current state of knowledge, and the preventive measures under consideration, so as to encourage the examination of the question
Acute Stressor Effects on Goal-Directed Action in Rats
Braun, Stephanie; Hauber, Wolfgang
2013-01-01
Here we examined effects of acute stressors that involve either systemic coadministration of corticosterone/yohimbine (3 mg/kg each) to increase glucocorticoid/noradrenaline activity (denoted as "pharmacological" stressor) or one or several distinct restraint stressors (denoted as "single" vs. "multiple" stressor) on…
Effectiveness of Mentoring Program Practices. Research in Action. Issue 2
DuBois, David L.
2007-01-01
This article focuses on mentoring program practices in relation to issues of effectiveness, while recognizing that implications for program quality conceptualized more broadly is a key concern in need of greater investigation. The author provides an overview of selected conceptual and methodological issues involved with identification of…
Renormalization-group flow of the effective action of cosmological large-scale structures
Floerchinger, Stefan
2017-01-01
Following an approach of Matarrese and Pietroni, we derive the functional renormalization group (RG) flow of the effective action of cosmological large-scale structures. Perturbative solutions of this RG flow equation are shown to be consistent with standard cosmological perturbation theory. Non-perturbative approximate solutions can be obtained by truncating the a priori infinite set of possible effective actions to a finite subspace. Using for the truncated effective action a form dictated by dissipative fluid dynamics, we derive RG flow equations for the scale dependence of the effective viscosity and sound velocity of non-interacting dark matter, and we solve them numerically. Physically, the effective viscosity and sound velocity account for the interactions of long-wavelength fluctuations with the spectrum of smaller-scale perturbations. We find that the RG flow exhibits an attractor behaviour in the IR that significantly reduces the dependence of the effective viscosity and sound velocity on the input ...
Estimation of several political action effects of energy prices
Directory of Open Access Journals (Sweden)
Andrew B. Whitford
2016-01-01
Full Text Available One important effect of price shocks in the United States has been increased political attention paid to the structure and performance of oil and natural gas markets, along with some governmental support for energy conservation. This article describes how price changes helped lead to the emergence of a political agenda accompanied by several interventions, as revealed through Granger causality tests on change in the legislative agenda.
Heart Surgery Waiting Time: Assessing the Effectiveness of an Action
Badakhshan, Abbas; Arab, Mohammad; Gholipour, Mahin; Behnampour, Naser; Saleki, Saeid
2015-01-01
Background: Waiting time is an index assessing patient satisfaction, managerial effectiveness and horizontal equity in providing health care. Although heart surgery centers establishment is attractive for politicians. They are always faced with the question of to what extent they solve patient’s problems. Objectives: The objective of this study was to evaluate factors influencing waiting time in patients of heart surgery centers, and to make recommendations for health-care policy-makers for r...
A call for action: comparative effectiveness research in asthma
Krishnan, Jerry A.; Schatz, Michael X.; Apter, Andrea J.
2010-01-01
Comparative effectiveness research (CER) has received considerable research attention in recent months, and efforts to promote CER are part of the newly enacted Patient Protection and Affordable Care Act. In this paper, we define CER, how it complements traditional efficacy research in asthma, and discuss how CER can help provide the basis for rational decision-making about the care of individual patients with asthma and how best to deliver this care in real-world settings. We present informa...
Guar gum: Its effects and mechanism of action in humans.
Tredger, Jacki A.
1984-01-01
In acute studies guar flour, guar powder and guar granules reduced mean post prandial insulin levels in normal subjects following liquid glucose. The flour and powder also reduced mean plasma GIP levels compared to glucose alone. Guar granules had no effect on the mean plasma glucose, insulin or GIP responses of either normal or non insulin dependent diabetic (NIDDM) subjects to a solid mixed meal but guar powder reduced mean post prandial plasma glucose, insulin, and GIP levels in both group...
International Nuclear Information System (INIS)
Anno, G.H.; Dore, M.A.
1978-04-01
In an airborne release of radioactive material from a nuclear power plant accident, sheltering of individuals is of importance in emergency protective action planning. An analysis to estimate the effectiveness or benefit that might be derived from sheltering is described. The objective of this effort is the development of sheltering effectiveness information for those responsible for formulating required emergency plans for nuclear power plant siting. Shelter effectiveness is specifically defined as the dose reduction factor (DRF). DRF estimates for different conditions of source release, shelter structure assumptions, and operational time parameters are made for both whole-body and thyroid doses separately, based on a single-compartment structural model of the time-varying outside and inside gaseous radionuclide sources of krypton, zenon, and iodine. Design basis accident (DBA) assumptions are made for the gaseous radionuclide release. The magnitude of the release and dose estimates are based on radionuclide data from The Reactor Safety Study (WASH-1400). Source release time and duration assumptions are related to release categories PWR 1, PWR 3, and PWR 4, for which release times range from 1.5 to 2.5 hr and the release duration ranges from 0.5 to 3 hr. The basic shelter model characteristics considered are gamma ray attentuation, source geometry, gaseous fission-product ingress, and air change rate. Temporal parameters considered are source release time and duration, cloud travel time, and time spent in the shelter structure. Also, the analysis of shelter effectiveness is based on a time-frame model, which can be conveniently related to other operational times important for emergency planning. In addition to developing shelter-effectiveness estimates parametrically, the advantage of exiting and evacuating the vicinity of the shelter area after some initial time in the shelter is analyzed from the standpoint of the DRF and temporal considerations
21 CFR 25.60 - Environmental effects abroad of major agency actions.
2010-04-01
... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Environmental effects abroad of major agency... SERVICES GENERAL ENVIRONMENTAL IMPACT CONSIDERATIONS Other Requirements § 25.60 Environmental effects abroad of major agency actions. (a) In accordance with Executive Order 12114, “Environmental Effects...
14 CFR 1216.321 - Environmental effects abroad of major Federal actions.
2010-01-01
... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Environmental effects abroad of major...) Other Requirements § 1216.321 Environmental effects abroad of major Federal actions. (a) In accordance with these procedures and E.O. 12114, “Environmental Effects Abroad of Major Federal Actions” (44 FR...
Effects of policosanol on gastroprotective action of D-002
Directory of Open Access Journals (Sweden)
Daisy Carbajal Quintana
Full Text Available Introduction: policosanol, a mixture of higher aliphatic alcohols purified from sugar cane wax, is used to treat hypercholesterolemia. D-002 (Abexol, a mixture of higher aliphatic alcohols from beeswax, is an antioxidant supplement with gastroprotective effects. Then, concomitant intake of D-002 and policosanol may occur in routine practice, so potential pharmacological interactions between them should be researched on. Objective: to find out the influence of policosanol on the gastroprotective effect of D-002 on the ethanol-induced gastric ulcer model. Methods: rats were randomized into eight groups: one treated with the vehicle (control, two with D-002 (25 and 200 mg/kg, two with policosanol (25 and 200 mg/kg, two with the same doses of D-002 + policosanol and other with sucralfate (100 mg/kg. Treatments were given as single oral doses. One hour after treatment, rats received 60% ethanol orally and one hour later they were killed and their stomachs exposed. Effects on ulcer indexes (UI were assessed. Results: acute oral administration of D-002 (25 and 200 mg/kg significantly reduced the ulcer indexes by 40 % and 68 %, respectively, as compared to the control group, and policosanol by 26 % and 47 %, respectively. The concomitant administration of the same doses of D-002 and policosanol significantly decreased ulcer indexes by 64 % (both given at 25 mg/kg and by 92 % (both given at 200 mg/kg as compared to the respective monotherapies. Sucralfate (100 mg/kg significantly reduced (@ 99 % ulcer indexes compared to the control group. Conclusions: the concomitant oral administration of policosanol with D-00 2 gives greater gastroprotection than D-002 monotherapy, so both products can be taken together.
Dose rate effects in the antioxidant action in polypropilene
International Nuclear Information System (INIS)
Novakovic, Lj.; Milosavljevic, B.H.
1998-01-01
Due to its economic importance, radiation induced oxidation of polypropylene (hereafter referred to as PP) has been studied by various methods to predict the stability of medical equipment sterilized with ionizing radiation. It is well documented that the deterioration proceeds via oxidation initiated by radiation. However, the mechanism is still not clear, because of complicated effects such as inhomogeneous oxidation, dependence of polymer morphology, and the effects of additives. Stabilization of PP to high energy radiation can be achieved by controlling the radical reactions as well as the oxidation reactions. The oxidation reactions can be controlled by dissolving one or more stabilizers into polymer products; synergistic effects are observed as well. These stabilizers not only protect PP during irradiation, but also provide a necessary and important long-term stability during the subsequent storage period. The large body of knowledge concerning polymer antioxidants is preeminently empirical and lacks the understanding of reaction kinetics and mechanisms. Stabilization of PP to high energy radiation induced oxidation is even more complex in the case of nuclear track membranes. The two diverse processes taking place in irradiated polymer during and after irradiation should be controlled and balanced; first, to promote a scission and increase the radical concentration in heavy ion tracks in order to enable and speed up the hole making process and second, to prevent oxidation in the unirradiated portion of polymer film in order to preserve good mechanical properties of the membrane. In order to solve this problem, detailed knowledge of the radiation induced reactions in irradiated PP and PP's chemistry of aging has to be gained. (author)
Managing effective reform for Community Medicine subject: Vision to actions
Directory of Open Access Journals (Sweden)
Amiruddin Kadri
2017-12-01
Full Text Available Reforming Community Medicine discipline is the felt need amongst fraternities of Community Medicine but making effective change is the greatest challenge. It is uphill task and many big organizations failed in ushering the change without full thought to how to manage reform? With changing demand and role of the subject, Royal Colleges of Physicians of United Kingdom had tried to change Faculty of Public Health to Faculty of Community Medicine and then to Faculty of Public Health Medicine to manage the change but it failed (1. However, we need to learn from them and succeed in managing the change.
Evolution of the violin: The law of effect in action.
Wasserman, Edward A; Cullen, Patrick
2016-01-01
As is true for most other human inventions, the origin of the violin is unknown. What is known is that this popular and versatile instrument has notably changed over the course of several hundred years. At issue is whether those evolutionary changes in the construction of the violin are the result of premeditated, intelligent design or whether they arose through a trial-and-error process. Recent scientific evidence favors the latter account. Our perspective piece puts these recent empirical findings into a comprehensive selectionist framework. According to this view, the many things we do and make--like violins--arise from a process of variation and selection which accords with the law of effect. Contrary to popular opinion, there is neither mystique nor romance in this process; it is as fundamental and ubiquitous as the law of natural selection. As with the law of natural selection in the evolution of organisms, there is staunch resistance to the role of the law of effect in the evolution of human inventions. We conclude our piece by considering several objections to our perspective. (c) 2016 APA, all rights reserved).
Antipyretic Effects of Citral and Possible Mechanisms of Action.
Emílio-Silva, Maycon T; Mota, Clarissa M D; Hiruma-Lima, Clélia A; Antunes-Rodrigues, José; Cárnio, Evelin C; Branco, Luiz G S
2017-10-01
Citral is a mixture of the two monoterpenoid isomers (neral and geranial) widely used as a health-promoting food additive safe for human and animal (approved by the US Food and Drug Administration). In vitro studies have reported on the capability of citral to reduce inflammation. Here, we report antipyretic effects of citral in vivo using the most well-accepted model of sickness syndrome, i.e., systemic administration of lipopolysaccharide ( LPS ) to rats. Citral given by gavage caused no change in control euthermic rats (treated with saline) but blunted most of the assessed parameters related to the sickness syndrome [fever (hallmark of infection), plasma cytokines (IL-1β, IL-6, and TNF-α) release, and prostaglandin E 2 (PGE 2 ) synthesis (both peripherally and hypothalamic)]. Moreover, LPS caused a sharp increase in plasma corticosterone levels that was unaltered by citral. These data are consistent with the notion that citral has a corticosterone-independent potent antipyretic effect, acting on the peripheral febrigenic signaling (plasma levels of IL-1β, IL-6, TNF-α, and PGE 2 ), eventually down-modulating hypothalamic PGE 2 production.
A simple and feasible method of effectiveness evaluation on radioactive decontamination action
International Nuclear Information System (INIS)
Chen Lin; Geng Xiaobing; Sun Jian; Wang Jihong; Guo Lijun
2012-01-01
Radioactive decontamination is a vital task in nuclear emergency response. The assessment of decontamination effectiveness is of great importance to decision-making. An index system for effectiveness evaluation of radioactive decontamination action in nuclear emergency response is produced. A method of decontamination effectiveness evaluation based on analytic hierarchy process and fuzzy comprehensive evaluation is presented. Index weights are determined through analytic hierarchy process. And scores of objects in each hierarchy are judged by fuzzy comprehensive evaluation. Then comprehensive effectiveness of the top object can be obtained, which can offer a basis for decision-making of decontamination action. (authors)
Paulus, Markus; Hunnius, Sabine; Bekkering, Harold
2013-10-01
Social transmission of knowledge is one of the reasons for human evolutionary success, and it has been suggested that already human infants possess eminent social learning abilities. However, nothing is known about the neurocognitive mechanisms that subserve infants' acquisition of novel action knowledge through the observation of other people's actions and their consequences in the physical world. In an electroencephalogram study on social learning in infancy, we demonstrate that 9-month-old infants represent the environmental effects of others' actions in their own motor system, although they never achieved these effects themselves before. The results provide first insights into the neurocognitive basis of human infants' unique ability for social learning of novel action knowledge.
Action-effect binding is decreased in motor conversion disorder: implications for sense of agency.
Kranick, Sarah M; Moore, James W; Yusuf, Nadia; Martinez, Valeria T; LaFaver, Kathrin; Edwards, Mark J; Mehta, Arpan R; Collins, Phoebe; Harrison, Neil A; Haggard, Patrick; Hallett, Mark; Voon, Valerie
2013-07-01
The abnormal movements seen in motor conversion disorder are affected by distraction and entrainment, similar to voluntary movement. Unlike voluntary movement, however, patients lack a sense of control for the abnormal movements, a failure of "self-agency." The action-effect binding paradigm has been used to quantify the sense of self-agency, because subjective contraction of time between an action and its effect only occurs if the patient feels that they are the agent responsible for the action. We used this paradigm, coupled with emotional stimuli, to investigate the sense of agency with voluntary movements in patients with motor conversion disorder. Twenty patients with motor conversion disorder and 20 age-matched and sex-matched healthy volunteers used a rotating clock to judge the time of their own voluntary key presses (action) and a subsequent auditory tone (effect) after they completed conditioning blocks in which high, medium, and low tones were coupled to images of happy, fearful, and neutral faces. The results replicated those produced previously: it was reported that an effect after a voluntary action occurred earlier, and the preceding action occurred later, compared with trials that used only key presses or tones. Patients had reduced overall binding scores relative to healthy volunteers, suggesting a reduced sense of agency. There was no effect of the emotional stimuli (faces) or other interaction effects. Healthy volunteers with subclinical depressive symptoms had higher overall binding scores. We demonstrate that patients with motor conversion disorder have decreased action-effect binding for normal voluntary movements compared with healthy volunteers, consistent with the greater experience of lack of control. Copyright © 2013 Movement Disorder Society.
Reviewing Biosphere Reserves globally: effective conservation action or bureaucratic label?
Coetzer, Kaera L; Witkowski, Edward T F; Erasmus, Barend F N
2014-02-01
The Biosphere Reserve (BR) model of UNESCO's Man and the Biosphere Programme reflects a shift towards more accountable conservation. Biosphere Reserves attempt to reconcile environmental protection with sustainable development; they explicitly acknowledge humans, and human interests in the conservation landscape while still maintaining the ecological values of existing protected areas. Conceptually, this model is attractive, with 610 sites currently designated globally. Yet the practical reality of implementing dual 'conservation' and 'development' goals is challenging, with few examples successfully conforming to the model's full criteria. Here, we review the history of Biosphere Reserves from first inception in 1974 to the current status quo, and examine the suitability of the designation as an effective conservation model. We track the spatial expansion of Biosphere Reserves globally, assessing the influence of the Statutory Framework of the World Network of Biosphere Reserves and Seville strategy in 1995, when the BR concept refocused its core objectives on sustainable development. We use a comprehensive range of case studies to discuss conformity to the Programme, the social and ecological consequences associated with implementation of the designation, and challenges in aligning conservation and development. Given that the 'Biosphere Reserve' label is a relatively unknown designation in the public arena, this review also provides details on popularising the Biosphere Reserve brand, as well as prospects for further research, currently unexploited, but implicit in the designation. © 2013 The Authors. Biological Reviews © 2013 Cambridge Philosophical Society.
Szabó, László; Szentandrássy, Norbert; Kistamás, Kornél; Hegyi, Bence; Ruzsnavszky, Ferenc; Váczi, Krisztina; Horváth, Balázs; Magyar, János; Bányász, Tamás; Pál, Balázs; Nánási, Péter P
2013-03-01
Tacrolimus is a commonly used immunosuppressive agent which causes cardiovascular complications, e.g., hypertension and hypertrophic cardiomyopathy. In spite of it, there is little information on the cellular cardiac effects of the immunosuppressive agent tacrolimus in larger mammals. In the present study, therefore, the concentration-dependent effects of tacrolimus on action potential morphology and the underlying ion currents were studied in canine ventricular cardiomyocytes. Standard microelectrode, conventional whole cell patch clamp, and action potential voltage clamp techniques were applied in myocytes enzymatically dispersed from canine ventricular myocardium. Tacrolimus (3-30 μM) caused a concentration-dependent reduction of maximum velocity of depolarization and repolarization, action potential amplitude, phase-1 repolarization, action potential duration, and plateau potential, while no significant change in the resting membrane potential was observed. Conventional voltage clamp experiments revealed that tacrolimus concentrations ≥3 μM blocked a variety of ion currents, including I(Ca), I(to), I(K1), I(Kr), and I(Ks). Similar results were obtained under action potential voltage clamp conditions. These effects of tacrolimus developed rapidly and were fully reversible upon washout. The blockade of inward currents with the concomitant shortening of action potential duration in canine myocytes is the opposite of those observed previously with tacrolimus in small rodents. It is concluded that although tacrolimus blocks several ion channels at higher concentrations, there is no risk of direct interaction with cardiac ion channels when applying tacrolimus in therapeutic concentrations.
Heart Surgery Waiting Time: Assessing the Effectiveness of an Action.
Badakhshan, Abbas; Arab, Mohammad; Gholipour, Mahin; Behnampour, Naser; Saleki, Saeid
2015-08-01
Waiting time is an index assessing patient satisfaction, managerial effectiveness and horizontal equity in providing health care. Although heart surgery centers establishment is attractive for politicians. They are always faced with the question of to what extent they solve patient's problems. The objective of this study was to evaluate factors influencing waiting time in patients of heart surgery centers, and to make recommendations for health-care policy-makers for reducing waiting time and increasing the quality of services from this perspective. This cross-sectional study was performed in 2013. After searching articles on PubMed, Elsevier, Google Scholar, Ovid, Magiran, IranMedex, and SID, a list of several criteria, which relate to waiting time, was provided. Afterwards, the data on waiting time were collected by a researcher-structured checklist from 156 hospitalized patients. The data were analyzed by SPSS 16. The Kolmogorov Smirnov and Shapiro tests were used for determination of normality. Due to the non-normal distribution, non-parametric tests, such as Kruskal-Wallis and Mann-Whitney were chosen for reporting significance. Parametric tests also used reporting medians. Among the studied variables, just economic status had a significant relation with waiting time (P = 0.37). Fifty percent of participants had diabetes, whereas this estimate was 43.58% for high blood pressure. As the cause of delay, 28.2% of patients reported financial problems, 18.6% personal problem and 13.5% a delay in providing equipment by the hospital. It seems the studied hospital should review its waiting time arrangements and detach them, as far as possible, from subjective and personal (specialists) decisions. On the other hand, ministries of health and insurance companies should consider more financial support. It is also recommend that hospitals should arrange preoperational psychiatric consultation for increasing patients' emotionally readiness.
Gravitational effective action at second order in curvature and gravitational waves
Calmet, Xavier; Capozziello, Salvatore; Pryer, Daniel
2017-09-01
We consider the full effective theory for quantum gravity at second order in curvature including non-local terms. We show that the theory contains two new degrees of freedom beyond the massless graviton: namely a massive spin-2 ghost and a massive scalar field. Furthermore, we show that it is impossible to fine-tune the parameters of the effective action to eliminate completely the classical spin-2 ghost because of the non-local terms in the effective action. Being a classical field, it is not clear anyway that this ghost is problematic. It simply implies a repulsive contribution to Newton's potential. We then consider how to extract the parameters of the effective action and show that it is possible to measure, at least in principle, the parameters of the local terms independently of each other using a combination of observations of gravitational waves and measurements performed by pendulum type experiments searching for deviations of Newton's potential.
Gravitational effective action at second order in curvature and gravitational waves
International Nuclear Information System (INIS)
Calmet, Xavier; Pryer, Daniel; Capozziello, Salvatore
2017-01-01
We consider the full effective theory for quantum gravity at second order in curvature including non-local terms. We show that the theory contains two new degrees of freedom beyond the massless graviton: namely a massive spin-2 ghost and a massive scalar field. Furthermore, we show that it is impossible to fine-tune the parameters of the effective action to eliminate completely the classical spin-2 ghost because of the non-local terms in the effective action. Being a classical field, it is not clear anyway that this ghost is problematic. It simply implies a repulsive contribution to Newton's potential. We then consider how to extract the parameters of the effective action and show that it is possible to measure, at least in principle, the parameters of the local terms independently of each other using a combination of observations of gravitational waves and measurements performed by pendulum type experiments searching for deviations of Newton's potential. (orig.)
Gravitational effective action at second order in curvature and gravitational waves.
Calmet, Xavier; Capozziello, Salvatore; Pryer, Daniel
2017-01-01
We consider the full effective theory for quantum gravity at second order in curvature including non-local terms. We show that the theory contains two new degrees of freedom beyond the massless graviton: namely a massive spin-2 ghost and a massive scalar field. Furthermore, we show that it is impossible to fine-tune the parameters of the effective action to eliminate completely the classical spin-2 ghost because of the non-local terms in the effective action. Being a classical field, it is not clear anyway that this ghost is problematic. It simply implies a repulsive contribution to Newton's potential. We then consider how to extract the parameters of the effective action and show that it is possible to measure, at least in principle, the parameters of the local terms independently of each other using a combination of observations of gravitational waves and measurements performed by pendulum type experiments searching for deviations of Newton's potential.
DEFF Research Database (Denmark)
Jensen, Ask Schou; Pennisi, Cristian Pablo; Sevcencu, Cristian
2015-01-01
with (+)-thioridazine. In this study we for the first time investigate the cardiotoxicity of the isolated thioridazine enantiomers and show their effects on ventricular repolarization. The effects of (+)-thioridazine, (-)-thioridazine, and racemate on the rabbit ventricular action potential duration (APD) were...... investigated in a randomized controlled blinded experiment. Action potentials were measured in papillary muscles isolated from 21 female rabbits, and the drug effect on 90% APD in comparison with control (DeltaDelta-APD90) was evaluated. Increasing concentrations of (+)-thioridazine and the racemate caused...
20 CFR 405.420 - Effect of Decision Review Board action on the right to seek judicial review.
2010-04-01
... § 405.420 Effect of Decision Review Board action on the right to seek judicial review. (a)(1) Subject to... must wait for the Board to take action. The appeal rights, if any, that will be available at that time... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Effect of Decision Review Board action on the...
Effect of Action Video Games on the Spatial Distribution of Visuospatial Attention
Green, C. Shawn; Bavelier, Daphne
2006-01-01
The authors investigated the effect of action gaming on the spatial distribution of attention. The authors used the flanker compatibility effect to separately assess center and peripheral attentional resources in gamers versus nongamers. Gamers exhibited an enhancement in attentional resources compared with nongamers, not only in the periphery but…
43 CFR 46.170 - Environmental effects abroad of major Federal actions.
2010-10-01
... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Environmental effects abroad of major... IMPLEMENTATION OF THE NATIONAL ENVIRONMENTAL POLICY ACT OF 1969 Protection and Enhancement of Environmental Quality § 46.170 Environmental effects abroad of major Federal actions. (a) In order to facilitate...
Individual and combined effects of enactment and testing on memory for action phrases.
Kubik, Veit; Söderlund, Hedvig; Nilsson, Lars-Göran; Jönsson, Fredrik U
2014-01-01
We investigated the individual and combined effects of enactment and testing on memory for action phrases to address whether both study techniques commonly promote item-specific processing. Participants (N = 112) were divided into four groups (n = 28). They either exclusively studied 36 action phrases (e.g., "lift the glass") or both studied and cued-recalled them in four trials. During study trials participants encoded the action phrases either by motorically performing them, or by reading them aloud, and they took final verb-cued recall tests over 18-min and 1-week retention intervals. A testing effect was demonstrated for action phrases, however, only when they were verbally encoded, and not when they were enacted. Similarly, enactive (relative to verbal) encoding reduced the rate of forgetting, but only when the action phrases were exclusively studied, and not when they were also tested. These less-than-additive effects of enactment and testing on the rate of forgetting, as well as on long-term retention, support the notion that both study techniques effectively promote item-specific processing that can only be marginally increased further by combining them.
Direct construction of the effective action of chiral gauge fermions in the anomalous sector
International Nuclear Information System (INIS)
Salcedo, L.L.
2009-01-01
The anomaly implies an obstruction to a fully chiral covariant calculation of the effective action in the abnormal-parity sector of chiral theories. The standard approach then is to reconstruct the anomalous effective action from its covariant current. In this work, we use a recently introduced formulation which allows one to directly construct the non-trivial chiral invariant part of the effective action within a fully covariant formalism. To this end we develop an appropriate version of Chan's approach to carry out the calculation within the derivative expansion. The result to four derivatives, i.e., to leading order in two and four dimensions and next-to-leading order in two dimensions, is explicitly worked out. Fairly compact expressions are found for these terms. (orig.)
The effective action for edge states in higher-dimensional quantum Hall systems
International Nuclear Information System (INIS)
Karabali, Dimitra; Nair, V.P.
2004-01-01
We show that the effective action for the edge excitations of a quantum Hall droplet of fermions in higher dimensions is generically given by a chiral bosonic action. We explicitly analyze the quantum Hall effect on complex projective spaces CP k , with a U(1) background magnetic field. The edge excitations are described by Abelian bosonic fields on S 2k-1 with only one spatial direction along the boundary of the droplet relevant for the dynamics. Our analysis also leads to an action for edge excitations for the case of the Zhang-Hu four-dimensional quantum Hall effect defined on S 4 with an SU(2) background magnetic field, using the fact that CP 3 is an S 2 -bundle over S 4
A continuous time model of the bandwagon effect in collective action
Arieh Gavious; Shlomo Mizrahi
2001-01-01
The paper offers a complex and systematic model of the bandwagon effect in collective action using continuous time equations. The model treats the bandwagon effect as a process influenced by ratio between the mobilization efforts of social activists and the resources invested by the government to counteract this activity. The complex modeling approach makes it possible to identify the conditions for specific types of the bandwagon effect, and determines the scope of that effect. Relying on ce...
On low-energy effective action in three-dimensional = 2 and = 4 supersymmetric electrodynamics
Buchbinder, I. L.; Merzlikin, B. S.; Samsonov, I. B.
2013-11-01
We discuss general structure of low-energy effective actions in = 2 and = 4 three-dimensional supersymmetric electrodynamics (SQED) in gauge superfield sector. There are specific terms in the effective action having no four-dimensional analogs. Some of these terms are responsible for the moduli space metric in the Coulomb branch of the theory. We find two-loop quantum corrections to the moduli space metric in the = 2 SQED and show that in the = 4 SQED the moduli space does not receive two-loop quantum corrections.
Quark contribution to the gluon Regge trajectory at NLO from the high energy effective action
International Nuclear Information System (INIS)
Chachamis, G.; Hentschinski, M.; Madrigal Martínez, J.D.; Sabio Vera, A.
2012-01-01
The two loop (NLO) diagrams with quark content contributing to the gluon Regge trajectory are computed within the framework of Lipatov's effective action for QCD, using the regularization procedure for longitudinal divergencies recently proposed by two of us in (M. Hentschinski and A. Sabio Vera, 2011). Perfect agreement with previous results in the literature is found, providing a robust check of the regularization prescription and showing that the high energy effective action is a very useful computational tool in the quasi-multi-Regge limit.
Directory of Open Access Journals (Sweden)
Anna eStenzel
2014-08-01
Full Text Available A co-actor’s intentionality has been suggested to be a key modulating factor for joint action effects like the joint Simon effect (JSE. However, in previous studies intentionality has often been confounded with agency defined as perceiving the initiator of an action as being the causal source of the action. The aim of the present study was to disentangle the role of agency and intentionality as modulating factors of the JSE. In Experiment 1, participants performed a joint go/nogo Simon task next to a co-actor who either intentionally controlled a response button with own finger movements (agency+/intentionality+ or who passively placed the hand on a response button that moved up and down on its own as triggered by computer signals (agency-/intentionality-. In Experiment 2, we included a condition in which participants believed that the co-actor intentionally controlled the response button with a Brain-Computer Interface while placing the response finger clearly besides the response button, so that the causal relationship between agent and action effect was perceptually disrupted (agency-/intentionality+. As a control condition, the response button was computer controlled while the co-actor placed the response finger besides the response button (agency-/intentionality-. We observed a JSE when the co-actor responded intentionally and the causal relationship between co-actor and action effect could be perceived, but not when the co-actor did not respond intentionally and the causal relationship was disrupted (Experiment 1. When the intentionality of the co-actor was maintained but the perception of the causal relationship between co-actor and action effect destroyed, the JSE was absent (Experiment 2. Our findings clearly indicate a vital role of a co-actor’s agency for the JSE and suggest that the ascription of agency is strongly perceptually grounded.
Kistamás, Kornél; Szentandrássy, Norbert; Hegyi, Bence; Ruzsnavszky, Ferenc; Váczi, Krisztina; Bárándi, László; Horváth, Balázs; Szebeni, Andrea; Magyar, János; Bányász, Tamás; Kecskeméti, Valéria; Nánási, Péter P
2013-06-15
Despite its widespread therapeutical use there is little information on the cellular cardiac effects of the antidiabetic drug pioglitazone in larger mammals. In the present study, therefore, the concentration-dependent effects of pioglitazone on ion currents and action potential configuration were studied in isolated canine ventricular myocytes using standard microelectrode, conventional whole cell patch clamp, and action potential voltage clamp techniques. Pioglitazone decreased the maximum velocity of depolarization and the amplitude of phase-1 repolarization at concentrations ≥3 μM. Action potentials were shortened by pioglitazone at concentrations ≥10 μM, which effect was accompanied with significant reduction of beat-to-beat variability of action potential duration. Several transmembrane ion currents, including the transient outward K(+) current (Ito), the L-type Ca(2+) current (ICa), the rapid and slow components of the delayed rectifier K(+) current (IKr and IKs, respectively), and the inward rectifier K(+) current (IK1) were inhibited by pioglitazone under conventional voltage clamp conditions. Ito was blocked significantly at concentrations ≥3 μM, ICa, IKr, IKs at concentrations ≥10 μM, while IK1 at concentrations ≥30 μM. Suppression of Ito, ICa, IKr, and IK1 has been confirmed also under action potential voltage clamp conditions. ATP-sensitive K(+) current, when activated by lemakalim, was effectively blocked by pioglitazone. Accordingly, action potentials were prolonged by 10 μM pioglitazone when the drug was applied in the presence of lemakalim. All these effects developed rapidly and were readily reversible upon washout. In conclusion, pioglitazone seems to be a harmless agent at usual therapeutic concentrations. Copyright © 2013 Elsevier B.V. All rights reserved.
Directory of Open Access Journals (Sweden)
Mi-Hee Lim
2017-02-01
Full Text Available Our objective in this study is to understand how adolescents respond to the food industry’s corporate social responsibility (CSR activities, especially the effects of such activities on consumers’ emotional responses, perceived authenticity, and attitudes toward the company. Understanding which types of CSR actions most inﬂuence adolescents is important for managers. This study examines adolescents’ responses to three types of CSR actions (career-related, environment-related, and wellbeing-related across two types of products (unhealthy and healthy foods. We ﬁnd that CSR actions related to career issues have the greatest effects on adolescents’ emotional responses, perceived authenticity,and attitudes toward a company under the condition of healthy food products. In other words, when a healthy food company offers a career-related CSR program, adolescents have better responses than when an unhealthy food company offers the same CSR program.
Covariant and background independent functional RG flow for the effective average action
Energy Technology Data Exchange (ETDEWEB)
Safari, Mahmoud; Vacca, Gian Paolo [Dipartimento di Fisica and INFN - Sezione di Bologna,via Irnerio 46, 40126 Bologna (Italy)
2016-11-23
We extend our prescription for the construction of a covariant and background-independent effective action for scalar quantum field theories to the case where momentum modes below a certain scale are suppressed by the presence of an infrared regulator. The key step is an appropriate choice of the infrared cutoff for which the Ward identity, capturing the information from single-field dependence of the ultraviolet action, continues to be exactly solvable, and therefore, in addition to covariance, manifest background independence of the effective action is guaranteed at any scale. A practical consequence is that in this framework one can adopt truncations dependent on the single total field. Furthermore we discuss the necessary and sufficient conditions for the preservation of symmetries along the renormalization group flow.
Effects of action planning and coping planning within the theory of planned behaviour
DEFF Research Database (Denmark)
Pakpour, Amir H.; Zedi, Isa mohammadi; Chatzisarantis, Nikos
2011-01-01
Objective: Patients on dialysis have low physical activity levels. The aim of the study was to examine the validity of action planning and coping planning within the theory of planned behaviour framework, for predicting physical activity behaviour of patients on hemodialysis. Methods: One hundred...... and forty four patients who were undergoing emodialysis were selected from dialysis centers. The mean age of the patients was 56.61 (SD= 11.38) years. The patients completed a questionnaire including variables from the theory of planned behaviour, action planning and coping planning. Physical activity...... was prospectively assessed at 4-weeks with the validated International Physical Activity Questionnaire self-report measure. A hierarchical regression analysis was performed to examine the effects of action planning and coping planning on physical activity behaviour. Results: There was a main effect for coping...
Effect of an educational game on university students' learning about action potentials.
Luchi, Kelly Cristina Gaviao; Montrezor, Luís Henrique; Marcondes, Fernanda K
2017-06-01
The aim of this study was to evaluate the effect of an educational game that is used for teaching the mechanisms of the action potentials in cell membranes. The game was composed of pieces representing the intracellular and extracellular environments, ions, ion channels, and the Na + -K + -ATPase pump. During the game activity, the students arranged the pieces to demonstrate how the ions move through the membrane in a resting state and during an action potential, linking the ion movement with a graph of the action potential. To test the effect of the game activity on student understanding, first-year dental students were given the game to play at different times in a series of classes teaching resting membrane potential and action potentials. In all experiments, students who played the game performed better in assessments. According to 98% of the students, the game supported the learning process. The data confirm the students' perception, indicating that the educational game improved their understanding about action potentials. Copyright © 2017 the American Physiological Society.
Dogge, M.; Gayet, S.; Custers, R.; Aarts, H.A.G.
2018-01-01
Perception is strongly shaped by the actions we perform. According to the theory of event coding, and forward models of motor control, goal-directed action preparation activates representations of desired effects. These expectations about the precise stimulus identity of one's action-outcomes (i.e.
Ramsey, John M.
1993-01-01
Reports the instructional effects of a formal environmental education methodology, issue investigation and action training (IIAT), on eighth-grade students. Focuses on whether IIAT can improve responsible environmental behavior in middle school students and whether variables associated with responsible adult environmental behavior will be…
Mehrdad, GOSHTASBPOUR; Center for Theoretical Physics and Mathematics, AEOI:Department of Physics, Shahid Beheshti University
1991-01-01
Extended D^†+D-DD^† Fujikawa regularization of anomaly and a method of integration of fermions for the chiral Schwinger model are criticized. On the basis of the corrected integration method, a new extended version of D^2 is obtained, resulting in the Jackiw-Rajaraman effective action.
Effective action for superfluid Fermi systems in the strong-coupling limit
International Nuclear Information System (INIS)
Dupuis, N.
2005-01-01
We derive the low-energy effective action for three-dimensional superfluid Fermi systems in the strong-coupling limit, where superfluidity originates from Bose-Einstein condensation of composite bosons. Taking into account density and pairing fluctuations on the same footing, we show that the effective action involves only the fermion density ρ r and its conjugate variable, the phase θ r of the pairing order parameter Δ r . We recover the standard action of a Bose superfluid of density ρ r /2, where the bosons have a mass m B =2m and interact via a repulsive contact potential with amplitude g B =4πa B /m B ,a B =2a (a the s-wave scattering length associated to the fermion-fermion interaction in vacuum). For lattice models, the derivation of the effective action is based on the mapping of the attractive Hubbard model onto the Heisenberg model in a uniform magnetic field, and a coherent state path integral representation of the partition function. The effective description of the Fermi superfluid in the strong-coupling limit is a Bose-Hubbard model with an intersite hopping amplitude t B =J/2 and an on-site repulsive interaction U B =2Jz, where J=4t 2 /U (t and -U are the intersite hopping amplitude and the on-site attraction in the (fermionic) Hubbard model, z the number of nearest-neighbor sites)
Effective action for superfluid Fermi systems in the strong-coupling limit
Dupuis, N.
2005-07-01
We derive the low-energy effective action for three-dimensional superfluid Fermi systems in the strong-coupling limit, where superfluidity originates from Bose-Einstein condensation of composite bosons. Taking into account density and pairing fluctuations on the same footing, we show that the effective action involves only the fermion density ρr and its conjugate variable, the phase θr of the pairing order parameter Δr . We recover the standard action of a Bose superfluid of density ρr/2 , where the bosons have a mass mB=2m and interact via a repulsive contact potential with amplitude gB=4πaB/mB,aB=2a ( a the s -wave scattering length associated to the fermion-fermion interaction in vacuum). For lattice models, the derivation of the effective action is based on the mapping of the attractive Hubbard model onto the Heisenberg model in a uniform magnetic field, and a coherent state path integral representation of the partition function. The effective description of the Fermi superfluid in the strong-coupling limit is a Bose-Hubbard model with an intersite hopping amplitude tB=J/2 and an on-site repulsive interaction UB=2Jz , where J=4t2/U ( t and -U are the intersite hopping amplitude and the on-site attraction in the (fermionic) Hubbard model, z the number of nearest-neighbor sites).
Non-abelian chiral anomalies and Wess-Zumino effective actions
International Nuclear Information System (INIS)
Petersen, J.L.
1984-06-01
An elementary account is given of the construction of anomalies and effective actions for Goldstone bosons, using the techniques of differential geometry. The emphasis is on simplicity of presentation, comparison of different renormalization schemes and the relationship to bosonization in the case of 2 dimensions. (Auth.)
LENUS (Irish Health Repository)
Birzniece, Vita
2010-05-01
The metabolic action of GH is attenuated by estrogens administered via the oral route. Selective estrogen receptor modulators lower IGF-I to a lesser degree than 17beta-estradiol in GH-deficient women, and their effect on fat and protein metabolism is unknown.
Effects of threat, trait anxiety and state anxiety on police officers’ actions during an arrest
Renden, Peter G.; Landman, Annemarie; Daalder, Nathalie R.; de Cock, Hans P.; Savelsbergh, Geert J. P.; Oudejans, Raôul R. D.
Purpose: We investigated the effects of threat and trait anxiety on state anxiety and how that affects police officers’ actions during an arrest. Most experiments on police performance under anxiety test the performance of one particular skill. Yet, police work often involves concerted use of a
Effects of threat, trait anxiety and state anxiety on police officers' actions during an arrest
Renden, P.G.; Landman, H.M.; Daalder, N.R.; de Cock, H.P.; Savelsbergh, G.J.P.; Oudejans, R.R.D.
Purpose: We investigated the effects of threat and trait anxiety on state anxiety and how that affects police officers' actions during an arrest. Most experiments on police performance under anxiety test the performance of one particular skill. Yet, police work often involves concerted use of a
Waters, Lea; Stokes, Helen
2015-01-01
This qualitative study describes the effect of two gratitude interventions designed to trigger emotion-gratitude (gratitude diary) and action-gratitude (gratitude letter) in school leaders. Case study methodology was applied to analyse reflective journals of 27 school leaders. The gratitude diary served to foster a more balanced view of the…
Effect of an Educational Game on University Students' Learning about Action Potentials
Luchi, Kelly Cristina Gaviao; Montrezor, Luís Henrique; Marcondes, Fernanda K.
2017-01-01
The aim of this study was to evaluate the effect of an educational game that is used for teaching the mechanisms of the action potentials in cell membranes. The game was composed of pieces representing the intracellular and extracellular environments, ions, ion channels, and the Na+-K+-ATPase pump. During the game activity, the students arranged…
Jung, H.; Carruthers, T.; Allison, M. A.; Weathers, D.; Moss, L.; Timmermans, H.
2017-12-01
Pacific Island communities are highly vulnerable to the effects of climate change, specifically accelerating rates of sea level rise, changes to storm intensity and associated rainfall patterns resulting in flooding and shoreline erosion. Nature-based adaptation is being planned not only to reduce the risk from shoreline erosion, but also to support benefits of a healthy ecosystem (e.g., supporting fisheries or coral reefs). In order to assess potential effectiveness of the nature-based actions to dissipate wave energy, two-dimensional X-Beach models were developed to predict the wave attenuation effect of coastal adaptation actions at the pilot sites—the villages of Naselesele and Somosomo on Taveuni island, Fiji. Both sites are experiencing serious shoreline erosion due to sea level rise and storm wave. The water depth (single-beam bathymetry), land elevation (truck-based LiDAR), and vegetation data including stem density and height were collected in both locations in a June 2017 field experiment. Wave height and water velocity were also measured for the model setup and calibration using a series of bottom-mounted instruments deployed in the 0-15 m water depth portions of the study grid. The calibrated model will be used to evaluate a range of possible adaptation actions identified by the community members of Naselesele and Somosomo. Particularly, multiple storm scenario runs with management-relevant shoreline restoration/adaptation options will be implemented to evaluate efficiencies of each adaptation action (e.g., no action, with additional planted trees, with sand mining, with seawalls constructed with natural materials, etc.). These model results will help to better understand how proposed adaption actions may influence future shoreline change and maximize benefits to communities in island nations across the SW Pacific.
Explicit learning of arbitrary and non-arbitrary action-effect relations in adults and 4-year-olds
Directory of Open Access Journals (Sweden)
Stephan Alexander eVerschoor
2012-02-01
Full Text Available Ideomotor theories claim that carrying out a movement that produces a perceivable effect creates a bidirectional association between the two, which can be used by action control processes to retrieve the associated action by anticipating its outcome. Indeed, previous implicit-learning studies have shown that practice renders novel but action-contingent stimuli effective retrieval cues of the action they used to follow, suggesting that experiencing sequences of actions and effects creates bidirectional action-effect associations. We investigated whether action-effect associations are also acquired under explicit-learning conditions and whether familiar action-effect relations (such as between a trumpet and a trumpet sound are learned the same way as novel, arbitrary relations are. We also investigated whether these factors affect adults and 4-year-old children equally. Our findings suggest that explicit learning produces the same bidirectional action-effect associations as implicit learning does, that non-arbitrary relations improve performance without affecting learning per se, and that adults and young children show equivalent performance—apart from the common observation that children have greater difficulty to withstand stimulus-induced action tendencies.
The Effect of Sympathetic Antagonists on the Antidepressant Action of Alprazolam
Directory of Open Access Journals (Sweden)
Gorash ZM
2008-01-01
Full Text Available Alprazolam is an anti-anxiety drug shown to be effective in the treatment of depression. In this study, the effect of sympathetic receptor antagonists on alprazolam–induced antidepressant action was studied using a mouse model of forced swimming behavioral despair. The interaction of three sympathetic receptor antagonists with benzodiazepines, which may impact the clinical use of alprazolam, was also studied. Behavioral despair was examined in six groups of albino mice. Drugs were administered intraperitoneally. The control group received only a single dose of 1% Tween 80. The second group received a single dose of alprazolam, and the third group received an antagonist followed by alprazolam. The fourth group was treated with imipramine, and the fifth group received an antagonist followed by imipramine. The sixth group was treated with a single dose of an antagonist alone (atenolol, a β1-selective adrenoceptor antagonist; propranolol, a non selective β-adrenoceptor antagonist; and prazocin, an α1-adrenoceptor antagonist. Results confirmed the antidepressant action of alprazolam and imipramine. Prazocin treatment alone produced depression, but it significantly potentiated the antidepressant actions of imipramine and alprazolam. Atenolol alone produced an antidepressant effect and potentiated the antidepressant action of alprazolam. Propranolol treatment alone produced depression, and antagonized the effects of alprazolam and imipramine, even producing depression in combined treatments. In conclusion, our results reveal that alprazolam may produce antidepressant effects through the release of noradrenaline, which stimulates β2 receptors to produce an antidepressant action. Imipramine may act by activating β2 receptors by blocking or down-regulating β1 receptors.
Unintended out-of-plane actions in size effect tests of structural concrete
International Nuclear Information System (INIS)
Ramallo, J.C.; Danesi, R.F.; Kotsovos, M.D.; Pavlovic, M.N.
1995-01-01
This paper is part of a larger research program on the causes of size-effect in structural concrete. The obtained results through the application of a nonlinear finite element analysis using material models extensive tested reliability, pointed out a possible connection between unintended out-of-plane actions and the ultimate strength of reinforced concrete (RC) structures, The computational analysis brought up unacceptable discrepancies only in those cases where possible unintended out-of-plane actions could not be negligible nor neutralized. Herein, it arises the need of experimental on such situations to inquire into the role played for those actions and. if they really were detected, to try to link them to some suitable parameters that would allow to take into account their presence in numerical analysis. (author). 13 refs., 4 figs., 3 tabs
Volchegorskiĭ, I A; Rassokhina, L M; Miroshnichenko, I Iu
2011-01-01
Relationship between the antihypoxic effect of 3-hydroxypyridine and succinic acid derivatives (emoxipine, reamberin and mexidol) and their effect on conditional learning, glycemia, and lipidemia was studied in rats with alloxan-induced diabetes. In parallel, the analogous relationship was investigated for alpha-lipoic acid that is regarded as a "gold standard" in treatment of diabetic neuropathy. It was established that single administration of emoxipine and mexidol in mice in doses equivalent to therapeutic-range doses in humans produces antihypoxic effect manifested by increased resistance to acute hypoxic hypoxia in test animals. Alpha-lipoic acid is inferior to emoxipin and mexidol in the degree of antihypoxic action. Reamberin does not exhibit this effect. The introduction of emoxipin, reamberin, mexidol, and alpha-lipoic acid in rats with alloxan diabetes during 7 or 14 days in doses equivalent to therapeutic-range doses in humans corrects conditional learning disorders in direct relationship with the antihypoxic activity of these drugs. The development of the nootropic effect of emoxipin, mexidol, and alpha-lipoic acid is related to a decrease in hyperglycemia and hyperlipidemia in rats with alloxan diabetes. The nootropic action of reamberin is accompanied by a transient hypoglycemizing effect and aggravation of dyslipidemic disorders. The antihypoxic activity of investigated drugs determines the direction and expression of their lipidemic effect, but is not correlated with the hypoglycemizing action these drugs on test animals with alloxan diabetes.
Effective Disclosure in the Fast-Fashion Industry: from Sustainability Reporting to Action
Directory of Open Access Journals (Sweden)
Sofia Garcia-Torres
2017-12-01
Full Text Available This work, set in the context of the apparel industry, proposes an action-oriented disclosure tool to help solve the sustainability challenges of complex fast-fashion supply chains (SCs. In a search for effective disclosure, it focusses on actions towards sustainability instead of the measurements and indicators of its impacts. We applied qualitative and quantitative content analysis to the sustainability reporting of the world’s two largest fast-fashion companies in three phases. First, we searched for the challenges that the organisations report they are currently facing. Second, we introduced the United Nations’ Sustainable Development Goals (SDGs framework to overcome the voluntary reporting drawback of ‘choosing what to disclose’, and revealed orphan issues. This broadened the scope from internal corporate challenges to issues impacting the ecosystems in which companies operate. Third, we analysed the reported sustainability actions and decomposed them into topics, instruments, and actors. The results showed that fast-fashion reporting has a broadly developed analysis base, but lacks action orientation. This has led us to propose the ‘Fast-Fashion Sustainability Scorecard’ as a universal disclosure framework that shifts the focus from (i reporting towards action; (ii financial performance towards sustainable value creation; and (iii corporate boundaries towards value creation for the broader SC ecosystem.
Prefrontal involvement in imitation learning of hand actions: effects of practice and expertise.
Vogt, Stefan; Buccino, Giovanni; Wohlschläger, Afra M; Canessa, Nicola; Shah, N Jon; Zilles, Karl; Eickhoff, Simon B; Freund, Hans-Joachim; Rizzolatti, Giacomo; Fink, Gereon R
2007-10-01
In this event-related fMRI study, we demonstrate the effects of a single session of practising configural hand actions (guitar chords) on cortical activations during observation, motor preparation and imitative execution. During the observation of non-practised actions, the mirror neuron system (MNS), consisting of inferior parietal and ventral premotor areas, was more strongly activated than for the practised actions. This finding indicates a strong role of the MNS in the early stages of imitation learning. In addition, the left dorsolateral prefrontal cortex (DLPFC) was selectively involved during observation and motor preparation of the non-practised chords. This finding confirms Buccino et al.'s [Buccino, G., Vogt, S., Ritzl, A., Fink, G.R., Zilles, K., Freund, H.-J., Rizzolatti, G., 2004a. Neural circuits underlying imitation learning of hand actions: an event-related fMRI study. Neuron 42, 323-334] model of imitation learning: for actions that are not yet part of the observer's motor repertoire, DLPFC engages in operations of selection and combination of existing, elementary representations in the MNS. The pattern of prefrontal activations further supports Shallice's [Shallice, T., 2004. The fractionation of supervisory control. In: Gazzaniga, M.S. (Ed.), The Cognitive Neurosciences, Third edition. MIT Press, Cambridge, MA, pp. 943-956] proposal of a dominant role of the left DLPFC in modulating lower level systems and of a dominant role of the right DLPFC in monitoring operations.
The Effects of Optical Illusions in Perception and Action in Peripersonal and Extrapersonal Space.
Shim, Jaeho; van der Kamp, John
2017-09-01
While the two visual system hypothesis tells a fairly compelling story about perception and action in peripersonal space (i.e., within arm's reach), its validity for extrapersonal space is very limited and highly controversial. Hence, the present purpose was to assess whether perception and action differences in peripersonal space hold in extrapersonal space and are modulated by the same factors. To this end, the effects of an optic illusion in perception and action in both peripersonal and extrapersonal space were compared in three groups that threw balls toward a target at a distance under different target eccentricity (i.e., with the target fixated and in peripheral field), viewing (i.e., binocular and monocular viewing), and delay conditions (i.e., immediate and delayed action). The illusory bias was smaller in action than in perception in peripersonal space, but this difference was significantly reduced in extrapersonal space, primarily because of a weakening bias in perception. No systematic modulation of target eccentricity, viewing, and delay arose. The findings suggest that the two visual system hypothesis is also valid for extra personal space.
Effect of actions promoting healthy eating on students' lipid profile: A controlled trial
Directory of Open Access Journals (Sweden)
Rita De Cássia Ribeiro-Silva
2014-04-01
Full Text Available OBJECTIVE: To assess the effect of nutrition intervention actions on the lipid profile of children and adolescents enrolled in public elementary schools. METHODS: This nine-month, controlled, intervention study included 202 students aged 7 to 14 years attending two schools (intervention/control located in a poor neighborhood of the municipality of Salvador, Bahia, Brazil. Actions were implemented in the intervention school to promote healthy eating habits, presented as "Ten steps to healthy eating". The effect of these actions was assessed by subjecting the students at baseline and end of the follow-up to biochemical, maturation, and anthropometric measurements and a produce intake survey. The dependent variables were the changes in the study biochemical parameters: total cholesterol, high density lipoprotein-cholesterol, low density lipoprotein-cholesterol, and triglycerides. Analysis of covariance assessed the changes that occurred over the study period. RESULTS: The mean total cholesterol, low-density lipoprotein-cholesterol, and triglycerides of the intervention students decreased 13.18 mg/dL (p=0.001, 7.41 mg/dL (p=0.038, and 12.37 mg/dL (p=0.029, respectively, compared with the control students. CONCLUSION: Actions of this nature have a positive impact on lipid profile. This study adds to those that use effective and viable public health strategies implementable at the primary care level.
Feature activation during word recognition: action, visual, and associative-semantic priming effects
Directory of Open Access Journals (Sweden)
Kevin J.Y. Lam
2015-05-01
Full Text Available Embodied theories of language postulate that language meaning is stored in modality-specific brain areas generally involved in perception and action in the real world. However, the temporal dynamics of the interaction between modality-specific information and lexical-semantic processing remain unclear. We investigated the relative timing at which two types of modality-specific information (action-based and visual-form information contribute to lexical-semantic comprehension. To this end, we applied a behavioral priming paradigm in which prime and target words were related with respect to (1 action features, (2 visual features, or (3 semantically associative information. Using a Go/No-Go lexical decision task, priming effects were measured across four different inter-stimulus intervals (ISI = 100 ms, 250 ms, 400 ms, and 1,000 ms to determine the relative time course of the different features . Notably, action priming effects were found in ISIs of 100 ms, 250 ms, and 1,000 ms whereas a visual priming effect was seen only in the ISI of 1,000 ms. Importantly, our data suggest that features follow different time courses of activation during word recognition. In this regard, feature activation is dynamic, measurable in specific time windows but not in others. Thus the current study (1 demonstrates how multiple ISIs can be used within an experiment to help chart the time course of feature activation and (2 provides new evidence for embodied theories of language.
Event-related potential effects of superior action anticipation in professional badminton players.
Jin, Hua; Xu, Guiping; Zhang, John X; Gao, Hongwei; Ye, Zuoer; Wang, Pin; Lin, Huiyan; Mo, Lei; Lin, Chong-De
2011-04-04
The ability to predict the trajectory of a ball based on the opponent's body kinematics has been shown to be critical to high-performing athletes in many sports. However, little is known about the neural correlates underlying such superior ability in action anticipation. The present event-related potential study compared brain responses from professional badminton players and non-player controls when they watched video clips of badminton games and predicted a ball's landing position. Replicating literature findings, the players made significantly more accurate judgments than the controls and showed better action anticipation. Correspondingly, they showed enlarged amplitudes of two ERP components, a P300 peaking around 350ms post-stimulus with a parietal scalp distribution and a P2 peaking around 250ms with a posterior-occipital distribution. The P300 effect was interpreted to reflect primed access and/or directing of attention to game-related memory representations in the players facilitating their online judgment of related actions. The P2 effect was suggested to reflect some generic learning effects. The results identify clear neural responses that differentiate between different levels of action anticipation associated with sports expertise. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.
Wynes, Seth; Nicholas, Kimberly A.
2017-07-01
Current anthropogenic climate change is the result of greenhouse gas accumulation in the atmosphere, which records the aggregation of billions of individual decisions. Here we consider a broad range of individual lifestyle choices and calculate their potential to reduce greenhouse gas emissions in developed countries, based on 148 scenarios from 39 sources. We recommend four widely applicable high-impact (i.e. low emissions) actions with the potential to contribute to systemic change and substantially reduce annual personal emissions: having one fewer child (an average for developed countries of 58.6 tonnes CO2-equivalent (tCO2e) emission reductions per year), living car-free (2.4 tCO2e saved per year), avoiding airplane travel (1.6 tCO2e saved per roundtrip transatlantic flight) and eating a plant-based diet (0.8 tCO2e saved per year). These actions have much greater potential to reduce emissions than commonly promoted strategies like comprehensive recycling (four times less effective than a plant-based diet) or changing household lightbulbs (eight times less). Though adolescents poised to establish lifelong patterns are an important target group for promoting high-impact actions, we find that ten high school science textbooks from Canada largely fail to mention these actions (they account for 4% of their recommended actions), instead focusing on incremental changes with much smaller potential emissions reductions. Government resources on climate change from the EU, USA, Canada, and Australia also focus recommendations on lower-impact actions. We conclude that there are opportunities to improve existing educational and communication structures to promote the most effective emission-reduction strategies and close this mitigation gap.
[Effect of pulse magnetic field on distribution of neuronal action potential].
Zheng, Yu; Cai, Di; Wang, Jin-Hai; Li, Gang; Lin, Ling
2014-08-25
The biological effect on the organism generated by magnetic field is widely studied. The present study was aimed to observe the change of sodium channel under magnetic field in neurons. Cortical neurons of Kunming mice were isolated, subjected to 15 Hz, 1 mT pulse magnetic stimulation, and then the currents of neurons were recorded by whole-cell patch clamp. The results showed that, under magnetic stimulation, the activation process of Na(+) channel was delayed, and the inactivation process was accelerated. Given the classic three-layer model, the polarization diagram of cell membrane potential distribution under pulse magnetic field was simulated, and it was found that the membrane potential induced was associated with the frequency and intensity of magnetic field. Also the effect of magnetic field-induced current on action potential was simulated by Hodgkin-Huxley (H-H) model. The result showed that the generation of action potential was delayed, and frequency and the amplitudes were decreased when working current was between -1.32 μA and 0 μA. When the working current was higher than 0 μA, the generation frequency of action potential was increased, and the change of amplitudes was not obvious, and when the working current was lower than -1.32 μA, the time of rising edge and amplitudes of action potential were decreased drastically, and the action potential was unable to generate. These results suggest that the magnetic field simulation can affect the distribution frequency and amplitude of action potential of neuron via sodium channel mediation.
Verkerk, Arie O.; Geuzebroek, Guillaume S. C.; Veldkamp, Marieke W.; Wilders, Ronald
2012-01-01
The autonomic nervous system controls heart rate and contractility through sympathetic and parasympathetic inputs to the cardiac tissue, with acetylcholine (ACh) and noradrenalin (NA) as the chemical transmitters. In recent years, it has become clear that specific Regulators of G protein Signaling proteins (RGS proteins) suppress muscarinic sensitivity and parasympathetic tone, identifying RGS proteins as intriguing potential therapeutic targets. In the present study, we have identified the effects of 1 μM ACh and 1 μM NA on the intrinsic action potentials of sinoatrial (SA) nodal and atrial myocytes. Single cells were enzymatically isolated from the SA node or from the left atrium of rabbit hearts. Action potentials were recorded using the amphotericin-perforated patch-clamp technique in the absence and presence of ACh, NA, or a combination of both. In SA nodal myocytes, ACh increased cycle length and decreased diastolic depolarization rate, whereas NA decreased cycle length and increased diastolic depolarization rate. Both ACh and NA increased maximum upstroke velocity. Furthermore, ACh hyperpolarized the maximum diastolic potential. In atrial myocytes stimulated at 2 Hz, both ACh and NA hyperpolarized the maximum diastolic potential, increased the action potential amplitude, and increased the maximum upstroke velocity. Action potential duration at 50 and 90% repolarization was decreased by ACh, but increased by NA. The effects of both ACh and NA on action potential duration showed a dose dependence in the range of 1–1000 nM, while a clear-cut frequency dependence in the range of 1–4 Hz was absent. Intermediate results were obtained in the combined presence of ACh and NA in both SA nodal and atrial myocytes. Our data uncover the extent to which SA nodal and atrial action potentials are intrinsically dependent on ACh, NA, or a combination of both and may thus guide further experiments with RGS proteins. PMID:22754533