scholarly journals Real-time warm pions from the lattice using an effective theory

2020 ◽  
Vol 35 (33) ◽  
pp. 2030021
Author(s):  
Sourendu Gupta ◽  
Rishi Sharma
Keyword(s):  
Analytic Continuation ◽  
Effective Field ◽  
Field Theories ◽  
Effective Theory ◽  
Explicit Computation ◽  
Crossover Temperature ◽  
Long Distance ◽  
Distance Correlation ◽  
Adequate Information ◽  
Minkowski Space Time

Lattice measurements provide adequate information to fix the parameters of long-distance effective field theories in Euclidean time. Using such a theory, we examine the analytic continuation of long-distance correlation functions of composite operators at finite temperature from Euclidean to Minkowski space–time. We show through an explicit computation that the analytic continuation of the pion correlation function is possible and gives rise to nontrivial effects. Among them is the possibility, supported by lattice computations of Euclidean correlators, that long distance excitations can be understood in terms of (very massive) pions even at temperatures higher than the QCD crossover temperature.

scholarly journals Predictive physics of inflation and grand unification for and from the CMB observations

2020 ◽  
Vol 35 (17) ◽  
pp. 2030008
Author(s):  
Norma G. Sanchez
Keyword(s):  
Effective Field Theories ◽  
Particle Physics ◽  
Effective Field ◽  
Energy Scale ◽  
Field Theories ◽  
Effective Theory ◽  
Grand Unification ◽  
Physical Approach ◽  
New Learning ◽  
The Future

This paper focuses on realistic and timely situations of inflation in connection with the CMB, gravitational and particle physics, adding interdisciplinarity and unification values within a strongly predictive physical approach. The formulation of inflation in the Ginsburg–Landau approach developed by de Vega and Sanchez1 and by Boyanovsky, de Vega, Sanchez and Destri[Formula: see text] clarifies and places inflation in the setting of the effective field theories of particle physics. In addition, it sets up a clean way to directly confront the inflationary predictions with the available and forthcoming CMB data and select a definitive model. All CMB[Formula: see text]+[Formula: see text]LSS data until now show how powerful is the Ginsburg–Landau effective theory of inflation in predicting observables in agreement with observations, including the inflation energy scale and the inflaton potential, and which has much more to provide in the future. It paves the way to discoveries, new learning and understanding.

LONG DISTANCE PHYSICS OF THE HALL FLUID AND THE ANYON SUPERFLUID

1991 ◽  
Vol 05 (10) ◽  
pp. 1629-1639
Author(s):  
A. ZEE
Keyword(s):  
Effective Field Theories ◽  
Effective Field ◽  
Field Theories ◽  
Mathematical Significance ◽  
Long Distance ◽  
Quantum Numbers ◽  
Chern Simons ◽  
Physical Quantities

The long distance physics of the Hall fluid and the anyon superfluid may be described by effective field theories constructed out of the Chern-Simons term. These theories are topological in character and may be of deep mathematical significance. Various physical quantities such as the quantum numbers of the quasiparticles are determined by a matrix appearing in the Chern-Simons term.

scholarly journals Extremal effective field theories

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Simon Caron-Huot ◽  
Vincent Van Duong
Keyword(s):  
Scalar Field ◽  
Scattering Amplitudes ◽  
Effective Field Theories ◽  
Convex Hull ◽  
Short Distance ◽  
Large Fraction ◽  
Effective Field ◽  
Field Theories ◽  
Long Distance ◽  
Distance Effects

Abstract Effective field theories (EFT) parameterize the long-distance effects of short-distance dynamics whose details may or may not be known. Previous work showed that EFT coefficients must obey certain positivity constraints if causality and unitarity are satisfied at all scales. We explore those constraints from the perspective of 2 → 2 scattering amplitudes of a light real scalar field, using semi-definite programming to carve out the space of allowed EFT coefficients for a given mass threshold M. We point out that all EFT parameters are bounded both below and above, effectively showing that dimensional analysis scaling is a consequence of causality. This includes the coefficients of s2 + t2 + u2 and stu type interactions. We present simple 2 → 2 extremal amplitudes which realize, or “rule in”, kinks in coefficient space and whose convex hull span a large fraction of the allowed space.

Effective Field Theories for Heavy Quarks: Heavy Quark Effective Theory and Heavy Quark Expansion

2020 ◽  
pp. 560-615
Author(s):  
Thomas Mannel
Keyword(s):  
Heavy Quark ◽  
Particle Physics ◽  
Operator Product Expansion ◽  
Effective Field ◽  
Field Theories ◽  
Effective Theory ◽  
Tree Level ◽  
Operator Product ◽  
Heavy Quark Effective Theory ◽  
Inclusive Decays

The heavy quark effective theory (HQET) and the heavy quark expansion (HQE) have developed into the standard tools in heavy-flavour physics. The lectures in this chapter introduce the basics of the approach and illustrates the methods by discussing some of their phenomenological applications. The chapter covers construction of the HQET Lagrangian, symmetries of HQET, HQET at one loop, and HQET applications to phenomenology. It also discusses HQE inclusive decays, operator product expansion (OPE), tree-level results, HQE parameters, QCD corrections, and end-point regions. It concludes by reiterating the enormous impact that both HQET and the HQE have had on particle physics phenomenology.

Introduction to Effective Field Theories and Inflation

2020 ◽  
pp. 220-306
Author(s):  
C. P. Burgess
Keyword(s):  
Effective Field Theories ◽  
Big Bang ◽  
Effective Field ◽  
Power Counting ◽  
Field Theories ◽  
Effective Theory ◽  
Inflationary Cosmology ◽  
Big Bang Theory ◽  
The Universe ◽  
Inflationary Models

The lecture notes presented in this chapter provide an introduction to inflationary cosmology with an emphasis on some of the ways effective field theories (EFTs) are used in its analysis. Topics covered in the chapter include introduction to cosmological backgrounds and fluctuations, including a brief discussion of inflationary models; general relativity as an effective theory; new issues raised by cosmology for EFTs, such as time-dependent backgrounds; and power-counting in cosmological EFTs. It also discusses issues surrounding the existence in the universe of both dark matter and dark energy, and the broader controversial question of their existence. It touches on the Hot Big Bang theory of cosmology, and the various types of particles believed to be 'elementary' at the temperatures of interest.

scholarly journals A new gauge-invariant double copy for heavy-mass effective theory

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Andreas Brandhuber ◽  
Gang Chen ◽  
Gabriele Travaglini ◽  
Congkao Wen
Keyword(s):  
Effective Field ◽  
Field Theories ◽  
Effective Theory ◽  
Leading Order ◽  
Gauge Invariant ◽  
Yang Mills ◽  
Crossing Symmetry ◽  
New Form ◽  
Set Up ◽  
Double Copy

Abstract We propose a new form of the colour-kinematics/double-copy duality for heavy-mass effective field theories, which we apply to construct compact expressions for tree amplitudes with heavy matter particles in Yang-Mills and in gravity to leading order in the mass. In this set-up, the new BCJ numerators are fixed uniquely and directly written in terms of field strengths, making gauge invariance manifest. Furthermore, they are local and automatically satisfy the Jacobi relations and crossing symmetry. We construct these BCJ numerators explicitly up to six particles. We also discuss relations of the BCJ numerators in the heavy-mass effective theory with those in pure Yang-Mills amplitudes.

scholarly journals P-wave quarkonium wavefunctions at the origin in the $$ \overline{\mathrm{MS}} $$ scheme

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Hee Sok Chung
Keyword(s):  
First Principles ◽  
Effective Field ◽  
Decay Rates ◽  
P Wave ◽  
Field Theories ◽  
Production Rates ◽  
Long Distance ◽  
Electromagnetic Decay ◽  
Ms Scheme ◽  
Physical Quantities

Abstract We compute P-wave quarkonium wavefunctions at the origin in the $$ \overline{\mathrm{MS}} $$ MS ¯ scheme based on nonrelativistic effective field theories. We include nonperturbative effects from the long-distance behaviors of the potential, while the short-distance behaviors are determined from perturbative QCD. We obtain $$ \overline{\mathrm{MS}} $$ MS ¯ -renormalized P-wave quarkonium wavefunctions at the origin that have the correct scale dependences that are expected from factorization formalisms, so that the dependences on the scheme and scale cancel in physical quantities. This greatly reduces the theoretical uncertainties associated with scheme and scale dependences in predictions of decay and production rates. Based on the calculation of the P-wave wavefunctions at the origin in this work, we make first-principles predictions of electromagnetic decay rates and exclusive electromagnetic production rates of P-wave charmonia and bottomonia, and compare them with measurements.

Heavy Quark Effective Theory: A Predictive EFT on the Lattice

2020 ◽  
pp. 616-649
Author(s):  
Rainer Sommer
Keyword(s):  
Monte Carlo ◽  
Perturbation Theory ◽  
Effective Field Theories ◽  
Monte Carlo Simulations ◽  
Large Scale ◽  
Effective Field ◽  
Field Theories ◽  
Effective Theory ◽  
Heavy Quark Effective Theory ◽  
Monte Carlo Techniques

The lattice formulation is a complete and unambiguous formulation of QCD. In principle it thus needs no tools beyond efficient Monte Carlo techniques. In practice various limits have to be taken where large-scale ratios occur. It is then advantageous to make use of effective field theories (EFTs). This chapter discusses the case of HQET, where the EFT itself is non-perturbative. It goes on to explain that retaining the full predictivity of QCD then requires to non-perturbatively formulate the theory and its matching to QCD, and to perform both steps by Monte Carlo simulations. Finally, it emphasizes conceptual points that appear when an EFT is treated beyond perturbation theory.

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.

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