scholarly journals Erratum to: Effective field theory after a new-physics discovery

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Stefan Alte ◽  
Matthias König ◽  
Matthias Neubert
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
New Physics ◽  
Effective Field ◽  
Momentum Fraction ◽  
Linear Relations ◽  
Right Hand ◽  
Anomalous Dimensions ◽  
The One ◽  
The Right

The two linear relations between operators shown in eq. (3.29) were missing an integral over the momentum fraction u on the right-hand side. In the one-particle anomalous dimensions in eq. (5.7) two fractions were mistyped.

scholarly journals The effective field theory of low scale see-saw at colliders

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Anke Biekötter ◽  
Mikael Chala ◽  
Michael Spannowsky
Keyword(s):  
Field Theory ◽  
Standard Model ◽  
Effective Field Theory ◽  
New Physics ◽  
Effective Field ◽  
Current Data ◽  
Missing Energy ◽  
Final State ◽  
Tau Decays ◽  
The Right

Abstract We study the Standard Model effective field theory ($$\nu $$νSMEFT) extended with operators involving right-handed neutrinos, focussing on the regime where the right-handed neutrinos decay promptly on collider scales to a photon and a Standard Model neutrino. This scenario arises naturally for right-handed neutrinos with masses of the order $$m_N \sim 0.1 \dots 10\, \,\text {GeV}$$mN∼0.1⋯10GeV. We limit the relevant dimension-six operator coefficients using LEP and LHC searches with photons and missing energy in the final state as well as pion and tau decays. While bounds on new physics contributions are generally in the TeV scale for order one operator coefficients, some coefficients, however, remain very poorly constrained or even entirely evade bounds from current data. Consequently, we identify such weakly constrained scenarios and propose new searches for rare top and tau decays involving photons to probe potential new physics in the $$\nu $$νSMEFT parameter space. Our analysis highlights the importance of performing dedicated searches for new rare tau and top decays.

scholarly journals Towards the renormalisation of the Standard Model effective field theory to dimension eight: Bosonic interactions I

2021 ◽  
Vol 11 (3) ◽  
Author(s):  
Mikael Chala ◽  
Guilherme Guedes ◽  
Maria Ramos ◽  
Jose Santiago
Keyword(s):  
Standard Model ◽  
Effective Field Theory ◽  
New Physics ◽  
Effective Field ◽  
Tree Level ◽  
Electroweak Phase Transition ◽  
Anomalous Dimensions ◽  
Weakly Coupled ◽  
The Standard Model ◽  
The One

We compute the one-loop renormalisation group running of the bosonic Standard Model effective operators to order v^4/\Lambda^4v4/Λ4, with v\sim 246v∼246 GeV being the electroweak scale and \LambdaΛ the unknown new physics threshold. We concentrate on the effects triggered by pairs of the leading dimension-six interactions, namely those that can arise at tree level in weakly-coupled ultraviolet completions of the Standard Model. We highlight some interesting consequences, including the interplay between positivity bounds and the form of the anomalous dimensions; the non-renormalisation of the SS and UU parameters; or the importance of radiative corrections to the Higgs potential for the electroweak phase transition. As a byproduct of this work, we provide a complete Green basis of operators involving only the Higgs and derivatives at dimension-eight, comprising 13 redundant interactions.

scholarly journals What is Leading Order for LFV in SMEFT?

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Marco Ardu ◽  
Sacha Davidson
Keyword(s):  
Effective Field Theory ◽  
New Physics ◽  
Effective Field ◽  
Power Counting ◽  
Leading Order ◽  
Small Power ◽  
Anomalous Dimensions ◽  
Simplifying Assumptions ◽  
The One ◽  
Lepton Flavour

Abstract Upcoming searches for lepton flavour change (LFV) aim to probe New Physics (NP) scales up to ΛNP ∼ 104 TeV, implying that they will be sensitive to NP at lower scales that is suppressed by loops or small couplings. We suppose that the NP responsable for LFV is beyond the reach of the LHC and can be parametrised in Effective Field Theory, introduce a small power-counting parameter λ (à la Cabibbo-Wolfenstein), and assess whether the existing dimension six operator basis and one-loop RGEs provide a good approximation for LFV. We find that μ ↔ e observables can be sensitive to a few dozen dimension eight operators, and to some effects of two-loop anomalous dimensions, for ΛNP ≲ 20 − 100 TeV. We also explore the effect of some simplifying assumptions in the one-loop RGEs, such as neglecting flavour-changing effects.

scholarly journals Renormalization Group evolution from on-shell SMEFT

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Minyuan Jiang ◽  
Teng Ma ◽  
Jing Shu
Keyword(s):  
Field Theory ◽  
Renormalization Group ◽  
Standard Model ◽  
Effective Field Theory ◽  
Effective Field ◽  
High Dimensional ◽  
Anomalous Dimensions ◽  
The Standard Model ◽  
Group Evolution

Abstract We describe the on-shell method to derive the Renormalization Group (RG) evolution of Wilson coefficients of high dimensional operators at one loop, which is a necessary part in the on-shell construction of the Standard Model Effective Field Theory (SMEFT), and exceptionally efficient based on the amplitude basis in hand. The UV divergence is obtained by firstly calculating the coefficients of scalar bubble integrals by unitary cuts, then subtracting the IR divergence in the massless bubbles, which can be easily read from the collinear factors we obtained for the Standard Model fields. Examples of deriving the anomalous dimensions at dimension six are presented in a pedagogical manner. We also give the results of contributions from the dimension-8 H4D4 operators to the running of V+V−H2 operators, as well as the running of B+B−H2D2n from H4D2n+4 for general n.

scholarly journals Precision Higgs couplings in neutral naturalness models: an effective field theory approach

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Lucien Heurtier ◽  
Hao-Lin Li ◽  
Huayang Song ◽  
Shufang Su ◽  
Wei Su ◽  
...  
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Goldstone Boson ◽  
Higgs Sector ◽  
New Physics ◽  
Effective Field ◽  
Precision Measurements ◽  
Global Symmetry ◽  
Theory Approach ◽  
Decay Channels

AbstractThe Higgs sector in neutral naturalness models provides a portal to the hidden sectors, and thus measurements of Higgs couplings at current and future colliders play a central role in constraining the parameter space of the model. We investigate a class of neutral naturalness models, in which the Higgs boson is a pseudo-Goldstone boson from the universal SO(N)/SO(N −1) coset structure. Integrating out the radial mode from the spontaneous global symmetry breaking, we obtain various dimension-six operators in the Standard Model effective field theory, and calculate the low energy Higgs effective potential with radiative corrections included. We perform aχ2fit to the Higgs coupling precision measurements at current and future colliders and show that the new physics scale could be explored up to 2.3 (2.4) TeV without (with) the Higgs invisible decay channels at future Higgs factories. The limits are comparable to the indirect constraints obtained via electroweak precision measurements.

scholarly journals Cosmological phase transitions: is effective field theory just a toy?

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Marieke Postma ◽  
Graham White
Keyword(s):  
Field Theory ◽  
Phase Transition ◽  
Phase Transitions ◽  
Effective Field Theory ◽  
New Physics ◽  
Effective Field ◽  
Tree Level ◽  
Dark Sector ◽  
First Order ◽  
First Order Phase

Abstract To obtain a first order phase transition requires large new physics corrections to the Standard Model (SM) Higgs potential. This implies that the scale of new physics is relatively low, raising the question whether an effective field theory (EFT) description can be used to analyse the phase transition in a (nearly) model-independent way. We show analytically and numerically that first order phase transitions in perturbative extensions of the SM cannot be described by the SM-EFT. The exception are Higgs-singlet extension with tree-level matching; but even in this case the SM-EFT can only capture part of the full parameter space, and if truncated at dim-6 operators, the description is at most qualitative. We also comment on the applicability of EFT techniques to dark sector phase transitions.

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 Geometry of orientifold vacua and supersymmetry breaking

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Thibaut Coudarchet ◽  
Emilian Dudas ◽  
Hervé Partouche
Keyword(s):  
Field Theory ◽  
Supersymmetry Breaking ◽  
Effective Field Theory ◽  
Scalar Potential ◽  
Open String ◽  
Closed String ◽  
Effective Field ◽  
Internal Space ◽  
Gravitino Mass ◽  
The One

Abstract Starting from a peculiar orientifold projection proposed long ago by Angelantonj and Cardella, we elaborate on a novel perturbative scenario that involves only D-branes, together with the two types of orientifold planes O± and anti-orientifold planes $$ {\overline{\mathrm{O}}}_{\pm } $$ O ¯ ± . We elucidate the microscopic ingredients of such models, connecting them to a novel realization of brane supersymmetry breaking. Depending on the position of the D-branes in the internal space, supersymmetry can be broken at the string scale on branes, or alternatively only at the massive level. The main novelty of this construction is that it features no NS-NS disk tadpoles, while avoiding open-string instabilities. The one-loop potential, which depends on the positions of the D-branes, is minimized for maximally broken, non-linearly realized supersymmetry. The orientifold projection and the effective field theory description reveal a soft breaking of supersymmetry in the closed-string sector. In such models it is possible to decouple the gravitino mass from the value of the scalar potential, while avoiding brane instabilities.

scholarly journals The one-loop tadpole in the geoSMEFT

2021 ◽  
Vol 11 (5) ◽  
Author(s):  
Tyler Corbett
Keyword(s):  
Field Theory ◽  
Standard Model ◽  
Effective Field Theory ◽  
Effective Field ◽  
Power Counting ◽  
Leading Order ◽  
The Standard Model ◽  
The One ◽  
Near Future ◽  
Geometric Formulation

Making use of the geometric formulation of the Standard Model Effective Field Theory we calculate the one-loop tadpole diagrams to all orders in the Standard Model Effective Field Theory power counting. This work represents the first calculation of a one-loop amplitude beyond leading order in the Standard Model Effective Field Theory, and discusses the potential to extend this methodology to perform similar calculations of observables in the near future.

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.

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