scholarly journals Operator bases in effective field theories with sterile neutrinos: d ≤ 9

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Hao-Lin Li ◽  
Zhe Ren ◽  
Ming-Lei Xiao ◽  
Jiang-Hao Yu ◽  
Yu-Hui Zheng
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Effective Field ◽  
Lepton Number ◽  
Low Energy ◽  
Field Theories ◽  
Sterile Neutrinos ◽  
Two Generations ◽  
Mass Dimension ◽  
Physical Effects

Abstract We obtain the complete and independent bases of effective operators at mass dimension 5, 6, 7, 8, 9 in both standard model effective field theory with light sterile right-handed neutrinos (νSMEFT) and low energy effective field theory with light sterile neutrinos (νLEFT). These theories provide systematical parametrizations on all possible Lorentz-invariant physical effects involving in the Majorana/Dirac neutrinos, with/without the lepton number violations. In the νSMEFT, we find that there are 2 (18), 29 (1614), 80 (4206), 323 (20400), 1358 (243944) independent operators with sterile neutrinos included at the dimension 5, 6, 7, 8, 9 for one (three) generation of fermions, while 24, 5223, 3966, 25425, 789426 independent operators in the νLEFT for two generations of up-type quarks and three generations of all other fermions.

scholarly journals Constraints on the charged currents in general neutrino interactions with sterile neutrinos

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Tong Li ◽  
Xiao-Dong Ma ◽  
Michael A. Schmidt
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Neutral Current ◽  
New Physics ◽  
Effective Field ◽  
Lepton Number ◽  
Low Energy ◽  
Electroweak Scale ◽  
Sterile Neutrinos ◽  
Neutrino Interactions

Abstract In this work we investigate the implication of low-energy precision measurements on the quark-lepton charged currents in general neutrino interactions with sterile neutrinos in effective field theories. The physics in low-energy measurements is described by the low-energy effective field theory extended with sterile neutrinos (LNEFT) defined below the electroweak scale. We also take into account renormalization group running and match the LNEFT onto the Standard Model (SM) effective field theory with sterile neutrinos (SMNEFT) to constrain new physics (NP) above the electroweak scale. The most sensitive low-energy probes are from leptonic decays of pseudoscalar mesons and hadronic tau lepton decays in terms of precise decay branching fractions, the lepton flavor universality and the Cabibbo-Kobayashi-Maskawa (CKM) unitarity. We also consider other constraints including nuclear beta decay. The constraints on charged current operators are generally stronger than the ones for quark-neutrino neutral current operators. We find that the most stringent bounds on the NP scale of lepton-number-conserving and lepton- number-violating operators in SMNEFT are 74 (110) TeV and 9.8 (13) TeV, respectively, for the operators with down (strange) quark.

scholarly journals Power counting and Wilsonian renormalization in nuclear effective field theory

2016 ◽  
Vol 25 (05) ◽  
pp. 1641007 ◽  
Author(s):  
Manuel Pavón Valderrama
Keyword(s):  
Field Theory ◽  
Effective Field Theories ◽  
Effective Field Theory ◽  
Nuclear Physics ◽  
High Energy ◽  
Effective Field ◽  
Power Counting ◽  
Low Energy ◽  
Field Theories ◽  
Nuclear Forces

Effective field theories are the most general tool for the description of low energy phenomena. They are universal and systematic: they can be formulated for any low energy systems we can think of and offer a clear guide on how to calculate predictions with reliable error estimates, a feature that is called power counting. These properties can be easily understood in Wilsonian renormalization, in which effective field theories are the low energy renormalization group evolution of a more fundamental — perhaps unknown or unsolvable — high energy theory. In nuclear physics they provide the possibility of a theoretically sound derivation of nuclear forces without having to solve quantum chromodynamics explicitly. However there is the problem of how to organize calculations within nuclear effective field theory: the traditional knowledge about power counting is perturbative but nuclear physics is not. Yet power counting can be derived in Wilsonian renormalization and there is already a fairly good understanding of how to apply these ideas to non-perturbative phenomena and in particular to nuclear physics. Here we review a few of these ideas, explain power counting in two-nucleon scattering and reactions with external probes and hint at how to extend the present analysis beyond the two-body problem.

scholarly journals Low energy effective field theory operator basis at d ≤ 9

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Hao-Lin Li ◽  
Zhe Ren ◽  
Ming-Lei Xiao ◽  
Jiang-Hao Yu ◽  
Yu-Hui Zheng
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Equation Of Motion ◽  
Effective Field ◽  
Lepton Number ◽  
Low Energy ◽  
Electroweak Scale ◽  
Integration By Parts ◽  
Motion Integration ◽  
Theory Operator

Abstract We obtain the complete operator bases at mass dimensions 5, 6, 7, 8, 9 for the low energy effective field theory (LEFT), which parametrize various physics effects between the QCD scale and the electroweak scale. The independence of the operator basis regarding the equation of motion, integration by parts and flavor relations, is guaranteed by our algorithm [1, 2], whose validity for the LEFT with massive fermions involved is proved by a generalization of the amplitude-operator correspondence. At dimension 8 and 9, we list the 35058 (756) and 704584 (3686) operators for three (one) generations of fermions categorized by their baryon and lepton number violations (∆B, ∆L), as these operators are of most phenomenological relevance.

scholarly journals Low-Energy Effective Field Theory below the Electroweak Scale: dimension-8 operators

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Christopher W. Murphy
Keyword(s):  
Field Theory ◽  
Standard Model ◽  
Effective Field Theory ◽  
Effective Field ◽  
Low Energy ◽  
Electroweak Scale ◽  
Left Handed ◽  
The Standard Model ◽  
Two Generations ◽  
Charged Leptons

Abstract We construct a complete basis of dimension-8 operators in the Low-Energy Effective Field Theory below the Electroweak Scale (LEFT). We find there are 35058 dimension-8 operators in the LEFT for two generations of up-type quarks and three generations of down-type quarks, charged leptons, and left-handed neutrinos. The existence of this operator basis is a necessary prerequisite for matching to the Standard Model Effective Field Theory at the dimension-8 level.

scholarly journals Effective field theory, past and future

2016 ◽  
Vol 31 (06) ◽  
pp. 1630007 ◽  
Author(s):  
Steven Weinberg
Keyword(s):  
Field Theory ◽  
General Relativity ◽  
Effective Field Theories ◽  
Standard Model ◽  
Effective Field Theory ◽  
Effective Field ◽  
Field Theories ◽  
Strong Interactions ◽  
The Standard Model ◽  
Theory Of Gravitation

I reminisce about the early development of effective field theories of the strong interactions, comment briefly on some other applications of effective field theories, and then take up the idea that the Standard Model and General Relativity are the leading terms in an effective field theory. Finally, I cite recent calculations that suggest that the effective field theory of gravitation and matter is asymptotically safe.

Effective field theory for low-energy QCD

2014 ◽  
pp. 200-236
Author(s):  
John F. Donoghue ◽  
Eugene Golowich ◽  
Barry R. Holstein
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Effective Field ◽  
Low Energy

scholarly journals Higgs compositeness in Sp(2N) gauge theories – Determining the low-energy constants with lattice calculations

2018 ◽  
Vol 175 ◽  
pp. 08011 ◽  
Author(s):  
Ed Bennett ◽  
Deog Ki Hong ◽  
Jong-Wan Lee ◽  
C.-J. David Lin ◽  
Biagio Lucini ◽  
...  
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Effective Field ◽  
Higgs Model ◽  
Low Energy ◽  
Dirac Fermion ◽  
Global Symmetry ◽  
Composite Higgs ◽  
Lattice Calculations ◽  
Energy Constants

As a first step towards a quantitative understanding of the SU(4)/Sp(4) composite Higgs model through lattice calculations, we discuss the low energy effective field theory resulting from the SU(4) → Sp(4) global symmetry breaking pattern. We then consider an Sp(4) gauge theory with two Dirac fermion flavours in the fundamental representation on a lattice, which provides a concrete example of the microscopic realisation of the SU(4)/Sp(4) composite Higgs model. For this system, we outline a programme of numerical simulations aiming at the determination of the low-energy constants of the effective field theory and we test the method on the quenched theory. We also report early results from dynamical simulations, focussing on the phase structure of the lattice theory and a calculation of the lowest-lying meson spectrum at coarse lattice spacing.

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