scholarly journals EFFECTIVE FIELD THEORY OF IDEAL-FLUID HYDRODYNAMICS

1996 ◽  
Vol 10 (21) ◽  
pp. 999-1010 ◽  
Author(s):  
ADRIAAN M.J. SCHAKEL

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.

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.


2014 ◽  
Vol 35 ◽  
pp. 1460431
Author(s):  
THOMAS MEHEN

This talk summarizes recent developments in quarkonium spectroscopy. I comment on the relation between the Zb(10610) and Zb(10650) and recently observed Zc(3900) and Zc(4025) states. Then I discuss a number of calculations using non-relativistic effective field theory for the X(3872), Zb(10610), and Zb(10650), under the assumption that these are shallow molecular bound states of charm or bottom mesons.


2015 ◽  
Vol 24 (12) ◽  
pp. 1544019 ◽  
Author(s):  
Carlos Barceló ◽  
Raúl Carballo-Rubio ◽  
Luis J. Garay

The cosmological constant problem can be understood as the failure of the decoupling principle behind effective field theory, so that some quantities in the low-energy theory are extremely sensitive to the high-energy properties. While this reflects the genuine character of the cosmological constant, finding an adequate effective field theory framework which avoids this naturalness problem may represent a step forward to understand nature. Following this intuition, we consider a minimal modification of the structure of general relativity which as an effective theory permits to work consistently at low energies, i.e. below the quantum gravity scale. This effective description preserves the classical phenomenology of general relativity and the particle spectrum of the standard model, at the price of changing our conceptual and mathematical picture of spacetime.


2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Jason Aebischer ◽  
Wouter Dekens ◽  
Elizabeth E. Jenkins ◽  
Aneesh V. Manohar ◽  
Dipan Sengupta ◽  
...  

Abstract We perform a model-independent analysis of the magnetic and electric dipole moments of the muon and electron. We give expressions for the dipole moments in terms of operator coefficients of the low-energy effective field theory (LEFT) and the Standard Model effective field theory (SMEFT). We use one-loop renormalization group improved perturbation theory, including the one-loop matching from SMEFT onto LEFT, and one-loop lepton matrix elements of the effective-theory operators. Semileptonic four-fermion operators involving light quarks give sizable non-perturbative contributions to the dipole moments, which are included in our analysis. We find that only a very limited set of the SMEFT operators is able to generate the current deviation of the magnetic moment of the muon from its Standard Model expectation.


2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Jason Aebischer ◽  
Christoph Bobeth ◽  
Andrzej J. Buras ◽  
Jacky Kumar ◽  
Mikołaj Misiak

Abstract We reconsider the complete set of four-quark operators in the Weak Effective Theory (WET) for non-leptonic ∆F = 1 decays that govern s → d and b → d, s transitions in the Standard Model (SM) and beyond, at the Next-to-Leading Order (NLO) in QCD. We discuss cases with different numbers Nf of active flavours, intermediate threshold corrections, as well as the issue of transformations between operator bases beyond leading order to facilitate the matching to high-energy completions or the Standard Model Effective Field Theory (SMEFT) at the electroweak scale. As a first step towards a SMEFT NLO analysis of K → ππ and non-leptonic B-meson decays, we calculate the relevant WET Wilson coefficients including two-loop contributions to their renormalization group running, and express them in terms of the Wilson coefficients in a particular operator basis for which the one-loop matching to SMEFT is already known.


Author(s):  
Antonio Pich

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.


2005 ◽  
Vol 19 (14) ◽  
pp. 2311-2319
Author(s):  
DEOG KI HONG ◽  
STEPHEN D. H. HSU

We study an effective field theory describing cold fermionic atoms near a Feshbach resonance. The effective theory gives a precise description of the dynamics in the limit that the energy of the Feshbach resonance is tuned to be twice that of the Fermi surface. We compute the zero temperature superfluid condensate in this limit, and obtain a critical temperature TC≃0.43 TF.


Proceedings ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 1
Author(s):  
Stephanie Baines

A resolution over the existence of magnetic charges has eluded the high energy physics community for centuries, and their search has gained momentum as recent models predict these may be observable at current colliders. They appear in field theories in two forms: the widely studied but heavily suppressed monopole with structure (soliton) and the not-so-well-covered point-like monopole. The latter was first proposed by Dirac as the source of a singular magnetic field and in effect symmetrises Maxwell’s equations. Following this line of research, work by S. Baines et al. analysed these sources as matter fields that carry spins 0, 1 2 , or 1, in an effective field theory that is perturbative for monopoles produced at threshold where the coupling strength g ( β ) is suppressed. All three cases are currently under investigation by the MoEDAL collaboration at CERN, and the theoretical expressions for kinematic distributions proposed in this work serve as guides to these searches. The cross section distributions in each case are derived from a U(1) invariant gauge theory. It is not assumed that, like the electron, the monopole’s magnetic moment is generated through spin interactions at minimal coupling, as it may be quite large. Instead, the analytical expressions in the spin 1 2 and 1 cases are kept completely general through the inclusion of a phenomenological parameter κ , related to the gyromagnetic ratio g R = 1 + κ . In fact, the inclusion of this parameter gives the effective theory validity in the high energy limit if the magnetic coupling scales with the particle’s velocity β = v c .


2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Varun Vaidya

Abstract I develop an Effective Field Theory (EFT) framework to compute jet substructure observables for heavy ion collision experiments. As an example, I consider dijet events that accompany the formation of a weakly coupled long lived Quark Gluon Plasma (QGP) medium in a heavy ion collision and look at an observable insensitive to jet selection bias: the simultaneous measurement of jet mass along with the transverse momentum imbalance between the jets that are groomed to remove soft radiation. Treating the jet as an open quantum system, I write down a factorization formula within the SCET (Soft Collinear Effective Theory) framework in the forward scattering regime. The physics of the medium is encoded in a universal soft field correlator while the jet-medium interaction is captured by a medium induced jet function. The factorization formula leads to a Lindblad type equation for the evolution of the reduced density matrix of the jet in the Markovian approximation. The solution for this equation allows a resummation of large logarithms that arise due to the final state measurements imposed while simultaneously summing over multiple incoherent interactions of the jet with the medium.


2003 ◽  
Vol 18 (11) ◽  
pp. 1959-1989 ◽  
Author(s):  
M. ZHONG ◽  
Y. L. WU ◽  
W. Y. WANG

B meson rare decays ([Formula: see text] and B → K* γ) are analyzed in the framework of effective field theory of heavy quarks. The semileptonic and penguin type form factors for these decays are calculated by using the light cone sum rules method at the leading order of 1/mQexpansion. Four exact relations between the two types of form factors are obtained at the leading order of 1/mQexpansion. In particular, the relations are found to hold for the whole momentum transfer region. We also investigate the validity of the relations resulting from the large energy effective theory based on the general relations obtained in the present approach. The branching ratios of the rare decays are presented and their potential importance for extracting the CKM matrix elements and probing new physics is emphasized.


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