scholarly journals Classical gravitational scattering from a gauge-invariant double copy

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Andreas Brandhuber ◽  
Gang Chen ◽  
Gabriele Travaglini ◽  
Congkao Wen
Keyword(s):  
Massive Particle ◽  
Radiation Reaction ◽  
Effective Field ◽  
Effective Theory ◽  
Tree Level ◽  
Theory Approach ◽  
Gauge Invariant ◽  
Scattering Angle ◽  
Four Dimensions ◽  
Double Copy

Abstract We propose a method to compute the scattering angle for classical black hole scattering directly from two massive particle irreducible diagrams in a heavy-mass effective field theory approach to general relativity, without the need of subtracting iteration terms. The amplitudes in this effective theory are constructed using a recently proposed novel colour-kinematic/double copy for tree-level two-scalar, multi-graviton amplitudes, where the BCJ numerators are gauge invariant and local with respect to the massless gravitons. These tree amplitudes, together with graviton tree amplitudes, enter the construction of the required D-dimensional loop integrands and allow for a direct extraction of contributions relevant for classical physics. In particular the soft/heavy-mass expansions of full integrands is circumvented, and all iterating contributions can be dropped from the get go. We use this method to compute the scattering angle up to third post-Minkowskian order in four dimensions, including radiation reaction contributions, also providing the expression of the corresponding integrand in D dimensions.

scholarly journals Massive gravity from double copy

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Arshia Momeni ◽  
Justinas Rumbutis ◽  
Andrew J. Tolley
Keyword(s):  
Sigma Model ◽  
Massive Gravity ◽  
Effective Field ◽  
Effective Theory ◽  
Nonlinear Sigma Model ◽  
Limit Theory ◽  
Four Dimensions ◽  
Yang Mills ◽  
Massive Spin ◽  
Double Copy

Abstract We consider the double copy of massive Yang-Mills theory in four dimensions, whose decoupling limit is a nonlinear sigma model. The latter may be regarded as the leading terms in the low energy effective theory of a heavy Higgs model, in which the Higgs has been integrated out. The obtained double copy effective field theory contains a massive spin-2, massive spin-1 and a massive spin-0 field, and we construct explicitly its interacting Lagrangian up to fourth order in fields. We find that up to this order, the spin-2 self interactions match those of the dRGT massive gravity theory, and that all the interactions are consistent with a Λ3 = (m2MPl)1/3 cutoff. We construct explicitly the Λ3 decoupling limit of this theory and show that it is equivalent to a bi-Galileon extension of the standard Λ3 massive gravity decoupling limit theory. Although it is known that the double copy of a nonlinear sigma model is a special Galileon, the decoupling limit of massive Yang-Mills theory is a more general Galileon theory. This demonstrates that the decoupling limit and double copy procedures do not commute and we clarify why this is the case in terms of the scaling of their kinematic factors.

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 Effective Theory Approach to Direct Detection of Dark Matter

2020 ◽  
pp. 650-688
Author(s):  
Junji Hisano
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Particle Physics ◽  
Direct Detection ◽  
Effective Field ◽  
Weakly Interacting Massive Particles ◽  
Effective Theory ◽  
Beyond The Standard Model ◽  
Theory Approach ◽  
The Standard Model

It is now certain that dark matter exists in the Universe. However, we do not know its nature, nor are there dark matter candidates in the standard model of particle physics or astronomy However, weakly interacting massive particles (WIMPs) in models beyond the standard model are one of the leading candidates available to provide explanation. The dark matter direct detection experiments, in which the nuclei recoiled by WIMPs are sought, are one of the methods to elucidate the nature of dark matter. This chapter introduces an effective field theory (EFT) approach in order to evaluate the nucleon–WIMP elastic scattering cross section.

scholarly journals Classical and quantum double copy of back-reaction

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Tim Adamo ◽  
Anton Ilderton
Keyword(s):  
Quantum Theory ◽  
Gauge Theory ◽  
Plane Wave ◽  
Tree Level ◽  
Back Reaction ◽  
Quantum Double ◽  
Four Dimensions ◽  
Helicity Formalism ◽  
Massive Spinor ◽  
Double Copy

Abstract We consider radiation emitted by colour-charged and massive particles crossing strong plane wave backgrounds in gauge theory and gravity. These backgrounds are treated exactly and non-perturbatively throughout. We compute the back-reaction on these fields from the radiation emitted by the probe particles: classically through background-coupled worldline theories, and at tree-level in the quantum theory through three-point amplitudes. Consistency of these two methods is established explicitly. We show that the gauge theory and gravity amplitudes are related by the double copy for amplitudes on plane wave backgrounds. Finally, we demonstrate that in four-dimensions these calculations can be carried out with a background-dressed version of the massive spinor-helicity formalism.

THE HEART OF FACTORIZATION

2014 ◽  
Vol 25 ◽  
pp. 1460014
Author(s):  
MATTHEW D. SCHWARTZ
Keyword(s):  
Effective Field Theory ◽  
Recent Progress ◽  
Gauge Theories ◽  
Effective Field ◽  
Effective Theory ◽  
Tree Level ◽  
Soft Collinear Effective Theory ◽  
Factorization Formula ◽  
The Many ◽  
Traditional Approaches

Factorization is at the heart of nearly any calculation in pertubative QCD. It follows from the universal behavior of gauge theories in soft and collinear limits. This talk gives a summary of recent progress on producing a more transparent understanding of factorization and connecting traditional approaches to those of Soft-Collinear Effective Theory. The main result is the formulation and proof, at tree-level, of a factorization formula in QCD. The proof exploits the many advantages of spinor helicity methods, but does not use any effective field theory tricks. Once the factorization formula is proven, the transition to an effective theory description is effortless.

scholarly journals Towards a complete mass spectrum of type-IIB flux vacua at large complex structure

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Jose J. Blanco-Pillado ◽  
Kepa Sousa ◽  
Mikel A. Urkiola ◽  
Jeremy M. Wachter
Keyword(s):  
Mass Spectrum ◽  
Complex Structure ◽  
Effective Field ◽  
Effective Theory ◽  
Tree Level ◽  
Large Complex ◽  
Common Strategy ◽  
Complete Computation ◽  
The Masses ◽  
Large Complex Structure

Abstract The large number of moduli fields arising in a generic string theory compactification makes a complete computation of the low energy effective theory infeasible. A common strategy to solve this problem is to consider Calabi-Yau manifolds with discrete symmetries, which effectively reduce the number of moduli and make the computation of the truncated Effective Field Theory possible. In this approach, however, the couplings (e.g., the masses) of the truncated fields are left undetermined. In the present paper we discuss the tree-level mass spectrum of type-IIB flux compactifications at Large Complex Structure, focusing on models with a reduced one-dimensional complex structure sector. We compute the tree-level spectrum for the dilaton and complex structure moduli, including the truncated fields, which can be expressed entirely in terms of the known couplings of the reduced theory. We show that the masses of this set of fields are naturally heavy at vacua consistent with the KKLT construction, and we discuss other phenomenologically interesting scenarios where the spectrum involves fields much lighter than the gravitino. We also derive the probability distribution for the masses on the ensemble of flux vacua, and show that it exhibits universal features independent of the details of the compactification. We check our results on a large sample of flux vacua constructed in an orientifold of the Calabi-Yau $$ {\mathbbm{W}\mathrm{\mathbb{P}}}_{\left[1,1,1,1,4\right]}^4 $$ W ℙ 1 1 1 1 4 4 . Finally, we also discuss the conditions under which the spectrum derived here could arise in more general compactifications.

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.

scholarly journals SMEFT atlas of ∆F = 2 transitions

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Jason Aebischer ◽  
Christoph Bobeth ◽  
Andrzej J. Buras ◽  
Jacky Kumar
Keyword(s):  
Top Quark ◽  
Effective Field ◽  
Effective Theory ◽  
Tree Level ◽  
Gauge Bosons ◽  
Travel Guide ◽  
The Standard Model ◽  
Individual Contributions ◽  
Model Independent ◽  
The Individual

Abstract We present a model-independent anatomy of the ∆F = 2 transitions K0−$$ {\overline{K}}^0 $$ K ¯ 0 , Bs,d−$$ {\overline{B}}_{s,d} $$ B ¯ s , d and D0−$$ {\overline{D}}^0 $$ D ¯ 0 in the context of the Standard Model Effective Field Theory (SMEFT). We present two master formulae for the mixing amplitude [M12]BSM. One in terms of the Wilson coefficients (WCs) of the Low-Energy Effective Theory (LEFT) operators evaluated at the electroweak scale μew and one in terms of the WCs of the SMEFT operators evaluated at the BSM scale Λ. The coefficients $$ {P}_a^{ij} $$ P a ij entering these formulae contain all the information below the scales μew and Λ, respectively. Renormalization group effects from the top-quark Yukawa coupling play the most important role. The collection of the individual contributions of the SMEFT operators to [M12]BSM can be considered as the SMEFT atlas of ∆F = 2 transitions and constitutes a travel guide to such transitions far beyond the scales explored by the LHC. We emphasize that this atlas depends on whether the down-basis or the up-basis for SMEFT operators is considered. We illustrate this technology with tree-level exchanges of heavy gauge bosons (Z′, G′) and corresponding heavy scalars.

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