scholarly journals EFFECTIVE FIELD THEORY OF A LOCALLY NONCOMMUTATIVE SPACE–TIME AND EXTRA DIMENSIONS

2008 ◽  
Vol 23 (16n17) ◽  
pp. 2613-2633 ◽  
Author(s):  
B. MIRZA ◽  
M. ZAREI
Keyword(s):  
Effective Field Theory ◽  
Extra Dimensions ◽  
Effective Field ◽  
Point Of View ◽  
Effective Theory ◽  
Noncommutative Space ◽  
Higher Dimension ◽  
Full Theory ◽  
Energy Theory ◽  
Effective Theories

We assume that the noncommutativity starts to be visible continuously from a scale ΛNC. According to this assumption, a two-loop effective action is derived for noncommutative ϕ4 and ϕ3 theories from a Wilsonian point of view. We show that these effective theories are free of UV/IR mixing phenomena. We also investigate the positivity constraint on coefficients of higher dimension operators present in the effective theory. This constraint makes the low energy theory to be UV completion of a full theory. Finally, we discuss noncommutativity and extra dimensions. In our effective theories formulated on noncommutative extra dimensions, if the campactification scale Λc is less than the scale ΛNC, the theory will not suffer from UV/IR mixing.

scholarly journals Effective Field Theory with Nambu–Goldstone Modes

2020 ◽  
pp. 137-219 ◽  
Author(s):  
Antonio Pich
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Dynamical Symmetry ◽  
New Physics ◽  
Effective Field ◽  
Low Energy ◽  
Effective Theory ◽  
Current Status ◽  
Symmetry Properties ◽  
Effective Theories

These lectures provide an introduction to the low-energy dynamics of Nambu–Goldstone fields, which associated with some spontaneous (or dynamical) symmetry breaking, using the powerful methods of effective field theory. The generic symmetry properties of these massless modes are described in detail and two very relevant phenomenological applications are worked out: chiral perturbation theory, the low-energy effective theory of QCD, and the (non-linear) electroweak effective theory. The similarities and differences between these two effective theories are emphasized, and their current status is reviewed. Special attention is given to the short-distance dynamical information encoded in the low-energy couplings of the effective Lagrangians. The successful methods developed in QCD could help us to uncover fingerprints of new physics scales from future measurements of the electroweak effective theory couplings.

scholarly journals LEADING LOGARITHMS IN FIELD THEORY

1999 ◽  
Vol 14 (11) ◽  
pp. 1769-1788 ◽  
Author(s):  
UGO AGLIETTI ◽  
GUIDO CORBÒ ◽  
LUCA TRENTADUE
Keyword(s):  
Field Theory ◽  
Form Factor ◽  
High Energy ◽  
Effective Theory ◽  
Sudakov Form Factor ◽  
Full Theory ◽  
High Energy Theory ◽  
Energy Theory ◽  
Effective Theories

We consider the Sudakov form factor in effective theories and we show that one can derive correctly the double logarithms of the original, high-energy, theory. We show that in effective theories it is possible to separate explicitly soft and hard dynamics, these being two regimes related to velocity conserving and to velocity changing operators respectively. A new effective theory is sketched which extracts the leading collinear singularities of the full theory amplitudes. Finally, we show how all leading logarithmic effects in field theory can be obtained by means of simple effective theories, where they correspond to a renormalization effect.

Effective Field Theory in Particle Physics and Cosmology

2020 ◽  
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Particle Physics ◽  
Large Scale ◽  
Effective Field ◽  
Effective Theory ◽  
Soft Collinear Effective Theory ◽  
Multiple Length Scales ◽  
Cosmological Observations ◽  
Standard Models

Effective field theory (EFT) is a general method for describing quantum systems with multiple-length scales in a tractable fashion. It allows us to perform precise calculations in established models (such as the standard models of particle physics and cosmology), as well as to concisely parametrize possible effects from physics beyond the standard models. EFTs have become key tools in the theoretical analysis of particle physics experiments and cosmological observations, despite being absent from many textbooks. This volume aims to provide a comprehensive introduction to many of the EFTs in use today, and covers topics that include large-scale structure, WIMPs, dark matter, heavy quark effective theory, flavour physics, soft-collinear effective theory, and more.

scholarly journals EFFECTIVE FIELD THEORY OF IDEAL-FLUID HYDRODYNAMICS

1996 ◽  
Vol 10 (21) ◽  
pp. 999-1010 ◽  
Author(s):  
ADRIAAN M.J. SCHAKEL
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Effective Field ◽  
Effective Theory ◽  
Goldstone Mode ◽  
Hydrodynamic Equations ◽  
Standard Description ◽  
Spontaneous Breakdown ◽  
Sound Mode ◽  
Fluid Hydrodynamics

Starting from a standard description of an ideal, isentropic fluid, we derive the effective theory governing a gapless non-relativistic mode — the sound mode. The theory, which is dictated by the requirement of Galilei invariance, entails the entire set of hydrodynamic equations. The gaplessness of the sound mode is explained by identifying it as the Goldstone mode associated with the spontaneous breakdown of Galilei invariance. Differences with a superfluid are pointed out.

scholarly journals MEDIATION OF SUPERSYMMETRY BREAKING IN EXTRA DIMENSIONS

2005 ◽  
Vol 20 (05) ◽  
pp. 297-312 ◽  
Author(s):  
CLAUDIO A. SCRUCCA
Keyword(s):  
Supersymmetry Breaking ◽  
Effective Field Theory ◽  
Extra Dimensions ◽  
Model Building ◽  
Realistic Model ◽  
Effective Field ◽  
Theory Approach ◽  
Classical Level ◽  
Gravitational Effects ◽  
Gravitational Fields

We review the mechanisms of supersymmetry breaking mediation that occur in sequestered models, where the visible and the hidden sectors are separated by an extra dimension and communicate only via gravitational interactions. By locality, soft breaking terms are forbidden at the classical level and reliably computable within an effective field theory approach at the quantum level. We present a self-contained discussion of these radiative gravitational effects and the resulting pattern of soft masses, and give an overview of realistic model building based on this setup. We consider both flat and warped extra dimensions, as well as the possibility that there be localized kinetic terms for the gravitational fields.

scholarly journals Effective theories with dark matter applications

2021 ◽  
Author(s):  
Subhaditya Bhattacharya ◽  
José Wudka
Keyword(s):  
Field Theory ◽  
Dark Matter ◽  
Effective Field Theory ◽  
Particle Physics ◽  
High Energy ◽  
New Physics ◽  
Effective Field ◽  
The Subject ◽  
Effective Theories ◽  
Detailed Nature

Standard Model (SM) of particle physics has achieved enormous success in describing the interactions among the known fundamental constituents of nature, yet it fails to describe phenomena for which there is very strong experimental evidence, such as the existence of dark matter, and which point to the existence of new physics not included in that model; beyond its existence, experimental data, however, have not provided clear indications as to the nature of that new physics. The effective field theory (EFT) approach, the subject of this review, is designed for this type of situations; it provides a consistent and unbiased framework within which to study new physics effects whose existence is expected but whose detailed nature is known very imperfectly. We will provide a description of this approach together with a discussion of some of its basic theoretical aspects. We then consider applications to high-energy phenomenology and conclude with a discussion of the application of EFT techniques to the study of dark matter physics and its possible interactions with the SM. In several of the applications we also briefly discuss specific models that are ultraviolet complete and may realize the effects described by the EFT.

scholarly journals Deformed General Relativity and Quantum Black Holes Interior

Universe ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. 39 ◽  
Author(s):  
Denis Arruga ◽  
Jibril Ben Achour ◽  
Karim Noui
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Einstein Equations ◽  
Gravity Models ◽  
Effective Theory ◽  
Hamiltonian Constraint ◽  
Spherically Symmetric ◽  
Full Generality ◽  
Full Theory ◽  
Effective Theories

Effective models of black holes interior have led to several proposals for regular black holes. In the so-called polymer models, based on effective deformations of the phase space of spherically symmetric general relativity in vacuum, one considers a deformed Hamiltonian constraint while keeping a non-deformed vectorial constraint, leading under some conditions to a notion of deformed covariance. In this article, we revisit and study further the question of covariance in these deformed gravity models. In particular, we propose a Lagrangian formulation for these deformed gravity models where polymer-like deformations are introduced at the level of the full theory prior to the symmetry reduction and prior to the Legendre transformation. This enables us to test whether the concept of deformed covariance found in spherically symmetric vacuum gravity can be extended to the full theory, and we show that, in the large class of models we are considering, the deformed covariance cannot be realized beyond spherical symmetry in the sense that the only deformed theory which leads to a closed constraints algebra is general relativity. Hence, we focus on the spherically symmetric sector, where there exist non-trivial deformed but closed constraints algebras. We investigate the possibility to deform the vectorial constraint as well and we prove that non-trivial deformations of the vectorial constraint with the condition that the constraints algebra remains closed do not exist. Then, we compute the most general deformed Hamiltonian constraint which admits a closed constraints algebra and thus leads to a well-defined effective theory associated with a notion of deformed covariance. Finally, we study static solutions of these effective theories and, remarkably, we solve explicitly and in full generality the corresponding modified Einstein equations, even for the effective theories which do not satisfy the closeness condition. In particular, we give the expressions of the components of the effective metric (for spherically symmetric black holes interior) in terms of the functions that govern the deformations of the theory.

WARPED COMPACTIFICATION ON SIGMA MODEL, SKYRMIONS IN SIX DIMENSIONS

2007 ◽  
Vol 22 (31) ◽  
pp. 5670-5684 ◽  
Author(s):  
Yuta Kodama ◽  
Kento Kokubu ◽  
Nobuyuki Sawado ◽  
Noriko Shiiki
Keyword(s):  
Field Theory ◽  
Cosmological Constant ◽  
Effective Field Theory ◽  
Extra Dimensions ◽  
Sigma Model ◽  
Effective Field ◽  
Winding Number ◽  
Bulk Cosmological Constant ◽  
Six Dimensions

We construct two distinct brane solutions in six dimensional effective field theory models. The CP 1 sigma model and the baby skyrmion realize warped compactification of the extra dimensions for negative bulk cosmological constant. Higher winding number solutions of the baby skyrmion are also presented.

scholarly journals EFT anomalous dimensions from the S-matrix

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Joan Elias Miró ◽  
James Ingoldby ◽  
Marc Riembau
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Form Factors ◽  
Effective Field ◽  
Higher Dimension ◽  
Powerful Method ◽  
Loop Contribution ◽  
Anomalous Dimensions ◽  
S Matrix ◽  
The Standard Model

Abstract We use the on-shell S-matrix and form factors to compute anomalous dimensions of higher dimension operators in the Standard Model Effective Field Theory. We find that in many instances, these computations are made simple by using the on-shell method. We first compute contributions to anomalous dimensions of operators at dimension-six that arise at one-loop. Then we calculate two-loop anomalous dimensions for which the corresponding one-loop contribution is absent, using this powerful method.

CHIRAL EFFECTIVE POTENTIAL WITH DELTA DEGREES OF FREEDOM

2009 ◽  
Vol 24 (02n03) ◽  
pp. 511-514
Author(s):  
H. KREBS ◽  
E. EPELBAUM ◽  
ULF-G. MEIßNER
Keyword(s):  
Effective Field Theory ◽  
Degrees Of Freedom ◽  
Effective Field ◽  
Chiral Expansion ◽  
Leading Order ◽  
Nuclear Forces ◽  
Charge Symmetry Breaking ◽  
Chiral Effective Field Theory ◽  
Charge Symmetry ◽  
Full Theory

Using chiral effective field theory (EFT) with explicit Δ degrees of freedom we calculated nuclear forces up to next-to-next-to-leading order (NNLO). We found much better convergence of the chiral expansion in all peripheral partial waves. We also observe strong cancellations between charge-symmetry-breaking (CSB) contributions due to nucleon- and Δ-mass splittings in the two-pion-exchange potentials. The CSB potentials appear to be weaker in the Δ-full theory.

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