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 A new perspective on the electroweak phase transition in the Standard Model Effective Field Theory

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
José Eliel Camargo-Molina ◽  
Rikard Enberg ◽  
Johan Löfgren
Keyword(s):  
Field Theory ◽  
Phase Transition ◽  
Standard Model ◽  
Effective Field Theory ◽  
New Physics ◽  
Effective Field ◽  
Quartic Coupling ◽  
Electroweak Phase Transition ◽  
First Order ◽  
The Standard Model

Abstract A first-order Electroweak Phase Transition (EWPT) could explain the observed baryon-antibaryon asymmetry and its dynamics could yield a detectable gravitational wave signature, while the underlying physics would be within the reach of colliders. The Standard Model, however, predicts a crossover transition. We therefore study the EWPT in the Standard Model Effective Field Theory (SMEFT) including dimension-six operators. A first-order EWPT has previously been shown to be possible in the SMEFT. Phenomenology studies have focused on scenarios with a tree-level barrier between minima, which requires a negative Higgs quartic coupling and a new physics scale low enough to raise questions about the validity of the EFT approach. In this work we stress that a first-order EWPT is also possible when the barrier between minima is generated radiatively, the quartic coupling is positive, the scale of new physics is higher, and there is good agreement with experimental bounds. Our calculation is done in a consistent, gauge-invariant way, and we carefully analyze the scaling of parameters necessary to generate a barrier in the potential. We perform a global fit in the relevant parameter space and explicitly find the points with a first-order transition that agree with experimental data. We also briefly discuss the prospects for probing the allowed parameter space using di-Higgs production in colliders.

Probing dark matter via effective field theory approach

2020 ◽  
Vol 17 (02) ◽  
pp. 2050028
Author(s):  
Ayşe Elçi̇boğa Kuday ◽  
Ferhat Özok ◽  
Erdinç Ulaş Saka
Keyword(s):  
Field Theory ◽  
Dark Matter ◽  
Cross Sections ◽  
Effective Field Theory ◽  
High Energy ◽  
New Physics ◽  
Theory Model ◽  
Effective Field ◽  
Tree Level ◽  
Theory Approach

We analyze dark matter in most general form of effective field theory approach. To examine the interactions between the weakly interacting massive particles (WIMPs) and the Standard Model (SM) particles, we use the six-dimensional EFT mediated by new physics scale [Formula: see text] at tree level. After implementing a new effective field theory model in FeynRules [FeynRules 2.0 A complete toolbox for tree-level phenomenology, Comput. Phys. Comm. 185(8) (2014) 2250–2300] We investigate the theory and constrain the theory by using relic density generated by MadDM [MadDM v.3.0: A Comprehensive tool for dark matter studies, Phys. Dark Univ. 24 (2019) 100249] tool of MadGraph5_aMC@NLO [The automated computation of tree-level and next-to-leading order differential cross-sections, and their matching to parton shower simulations, J. High Energy Phys. 79 (2014) 2014].

scholarly journals Towards Feynman rules for conformal blocks

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Sarah Hoback ◽  
Sarthak Parikh
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Hypergeometric Functions ◽  
Power Series Expansion ◽  
Effective Field ◽  
Conformal Block ◽  
Tree Level ◽  
Conformal Blocks ◽  
Simple Set ◽  
Feynman Rules

Abstract We conjecture a simple set of “Feynman rules” for constructing n-point global conformal blocks in any channel in d spacetime dimensions, for external and exchanged scalar operators for arbitrary n and d. The vertex factors are given in terms of Lauricella hypergeometric functions of one, two or three variables, and the Feynman rules furnish an explicit power-series expansion in powers of cross-ratios. These rules are conjectured based on previously known results in the literature, which include four-, five- and six-point examples as well as the n-point comb channel blocks. We prove these rules for all previously known cases, as well as two new ones: the seven-point block in a new topology, and all even-point blocks in the “OPE channel.” The proof relies on holographic methods, notably the Feynman rules for Mellin amplitudes of tree-level AdS diagrams in a scalar effective field theory, and is easily applicable to any particular choice of a conformal block beyond those considered in this paper.

scholarly journals Electric properties of olive oil under pressure

2021 ◽  
Author(s):  
L. T. Pawlicki ◽  
R. M. Siegoczyński ◽  
S. Ptasznik ◽  
K. Marszałek
Keyword(s):  
Molecular Structure ◽  
Phase Transition ◽  
Phase Diagram ◽  
Phase Transitions ◽  
Olive Oil ◽  
Material Parameters ◽  
First Order ◽  
Long Time ◽  
Capacitive Reactance ◽  
First Order Phase

AbstractThe main purpose of the experiment was a thermodynamic research with use of the electric methods chosen. The substance examined was olive oil. The paper presents the resistance, capacitive reactance, relative permittivity and resistivity of olive. Compression was applied with two mean velocities up to 450 MPa. The results were shown as functions of pressure and time and depicted on the impedance phase diagram. The three first order phase transitions have been detected. All the changes in material parameters were observed during phase transitions. The material parameters measured turned out to be the much more sensitive long-time phase transition factors than temperature. The values of material parameters and their dependence on pressure and time were compared with the molecular structure, arrangement of molecules and interactions between them. Knowledge about olive oil parameters change with pressure and its phase transitions is very important for olive oil production and conservation.

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 Theoretical uncertainties for cosmological first-order phase transitions

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Djuna Croon ◽  
Oliver Gould ◽  
Philipp Schicho ◽  
Tuomas V. I. Tenkanen ◽  
Graham White
Keyword(s):  
Phase Transitions ◽  
Standard Model ◽  
Scale Dependence ◽  
Effective Field ◽  
Bubble Nucleation ◽  
Perturbative Approach ◽  
First Order ◽  
The Standard Model ◽  
First Order Phase ◽  
Renormalisation Scale

Abstract We critically examine the magnitude of theoretical uncertainties in perturbative calculations of fist-order phase transitions, using the Standard Model effective field theory as our guide. In the usual daisy-resummed approach, we find large uncertainties due to renormalisation scale dependence, which amount to two to three orders-of-magnitude uncertainty in the peak gravitational wave amplitude, relevant to experiments such as LISA. Alternatively, utilising dimensional reduction in a more sophisticated perturbative approach drastically reduces this scale dependence, pushing it to higher orders. Further, this approach resolves other thorny problems with daisy resummation: it is gauge invariant which is explicitly demonstrated for the Standard Model, and avoids an uncontrolled derivative expansion in the bubble nucleation rate.

scholarly journals Dissipation in the effective field theory for hydrodynamics: First-order effects

2013 ◽  
Vol 88 (10) ◽  
Author(s):  
Solomon Endlich ◽  
Alberto Nicolis ◽  
Rafael A. Porto ◽  
Junpu Wang
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Effective Field ◽  
Order Effects ◽  
First Order

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.

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