scholarly journals Non-relativistic and potential non-relativistic effective field theories for scalar mediators

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Simone Biondini ◽  
Vladyslav Shtabovenko
Keyword(s):  
Effective Field ◽  
Field Theories ◽  
Dirac Fermions ◽  
Full Generality ◽  
Relativistic Limit ◽  
Cosmological Observations ◽  
The Standard Model ◽  
Light Scalar ◽  
Model Independent ◽  
Yukawa Theory

Abstract Yukawa-type interactions between heavy Dirac fermions and a scalar field are a common ingredient in various extensions of the Standard Model. Despite of that, the non-relativistic limit of the scalar Yukawa theory has not yet been studied in full generality in a rigorous and model-independent way. In this paper we intend to fill this gap by initiating a series of investigations that make use of modern effective field theory (EFT) techniques. In particular, we aim at constructing suitable non-relativistic and potential non-relativistic EFTs of Yukawa interactions (denoted as NRY and pNRY respectively) in close analogy to the well known and phenomenologically successful non-relativistic QCD (NRQCD) and potential non-relativistic QCD (pNRQCD). The phenomenological motivation for our study lies in the possibility to explain the existing cosmological observations by introducing heavy fermionic dark matter particles that interact with each other by exchanging a light scalar mediator. A systematic study of this compelling scenario in the framework of non-relativistic EFTs (NREFTs) constitutes the main novelty of our approach as compared to the existing studies.

scholarly journals New physics at the FCC-ee: indirect discovery potential

2021 ◽  
Vol 136 (9) ◽  
Author(s):  
Jorge de Blas
Keyword(s):  
Effective Field Theories ◽  
Standard Model ◽  
New Physics ◽  
Effective Field ◽  
Point Of View ◽  
Field Theories ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
Discovery Potential ◽  
Model Independent

AbstractWe review the projected sensitivity to physics beyond the Standard Model via indirect searches at the Future$$e+e-$$ e + e - Circular Collider (FCC-ee). The indirect sensitivity to new physics is discussed both from a model-independent perspective, using the formalism of Effective Field Theories, but also from the point of view of more specific classes of well-motivated models.

scholarly journals A note on gauge anomaly cancellation in effective field theories

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Ferruccio Feruglio
Keyword(s):  
Effective Field Theories ◽  
Effective Field ◽  
Field Theories ◽  
Anomaly Cancellation ◽  
Charge Assignment ◽  
The Standard Model ◽  
Renormalizable Theory ◽  
Complete Set ◽  
Gauge Anomalies ◽  
Gauge Anomaly

Abstract The conditions for the absence of gauge anomalies in effective field theories (EFT) are rivisited. General results from the cohomology of the BRST operator do not prevent potential anomalies arising from the non-renormalizable sector, when the gauge group is not semi-simple, like in the Standard Model EFT (SMEFT). By considering a simple explicit model that mimics the SMEFT properties, we compute the anomaly in the regularized theory, including a complete set of dimension six operators. We show that the dependence of the anomaly on the non-renormalizable part can be removed by adding a local counterterm to the theory. As a result the condition for gauge anomaly cancellation is completely controlled by the charge assignment of the fermion sector, as in the renormalizable theory.

scholarly journals Non-standard interactions in SMEFT confronted with terrestrial neutrino experiments

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Yong Du ◽  
Hao-Lin Li ◽  
Jian Tang ◽  
Sampsa Vihonen ◽  
Jiang-Hao Yu
Keyword(s):  
Neutrino Oscillation ◽  
New Physics ◽  
Effective Field ◽  
Scalar Leptoquark ◽  
Double Chooz ◽  
The Standard Model ◽  
Reactor Neutrino ◽  
Model Independent ◽  
Neutrino Experiments ◽  
Individual Dimension

Abstract The Standard Model Effective Field Theory (SMEFT) provides a systematic and model-independent framework to study neutrino non-standard interactions (NSIs). We study the constraining power of the on-going neutrino oscillation experiments T2K, NOνA, Daya Bay, Double Chooz and RENO in the SMEFT framework. A full consideration of matching is provided between different effective field theories and the renormalization group running at different scales, filling the gap between the low-energy neutrino oscillation experiments and SMEFT at the UV scale. We first illustrate our method with a top- down approach in a simplified scalar leptoquark model, showing more stringent constraints from the neutrino oscillation experiments compared to collider studies. We then provide a bottom-up study on individual dimension-6 SMEFT operators and find NSIs in neutrino experiments already sensitive to new physics at ∼20 TeV when the Wilson coefficients are fixed at unity. We also investigate the correlation among multiple operators at the UV scale and find it could change the constraints on SMEFT operators by several orders of magnitude compared with when only one operator is considered. Furthermore, we find that accelerator and reactor neutrino experiments are sensitive to different SMEFT operators, which highlights the complementarity of the two experiment types.

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.

scholarly journals MODEL INDEPENDENT RESULTS FOR HEAVY QUARKONIUM

2004 ◽  
Vol 19 (21) ◽  
pp. 1563-1576
Author(s):  
JOAN SOTO
Keyword(s):  
Effective Field Theories ◽  
Effective Field ◽  
Field Theories ◽  
Heavy Quarkonium ◽  
Potential Models ◽  
Inclusive Decays ◽  
Model Independent ◽  
Relativistic Potential ◽  
Effective Theories

We review a number of results for the spectrum and inclusive decays of heavy quarkonium systems which can be derived from QCD under well controlled approximations. They essentially follow from the hierarchy of scales in these systems, which can be efficiently exploited using non-relativistic effective field theories. In particular, we discuss under which conditions non-relativistic potential models emerge as effective theories of QCD.

scholarly journals 2, 84, 30, 993, 560, 15456, 11962, 261485, . . .: higher dimension operators in the SM EFT

2017 ◽  
Vol 2017 (8) ◽  
Author(s):  
Brian Henning ◽  
Xiaochuan Lu ◽  
Tom Melia ◽  
Hitoshi Murayama
Keyword(s):  
Equations Of Motion ◽  
Companion Paper ◽  
Effective Field ◽  
Conformal Group ◽  
Field Theories ◽  
Irreducible Representations ◽  
Higher Dimension ◽  
The Standard Model ◽  
Mass Dimension ◽  
Fermion Generation

Abstract In a companion paper [1], we show that operator bases for general effective field theories are controlled by the conformal algebra. Equations of motion and integration by parts identities can be systematically treated by organizing operators into irreducible representations of the conformal group. In the present work, we use this result to study the standard model effective field theory (SM EFT), determining the content and number of higher dimension operators up to dimension 12, for an arbitrary number of fermion generations. We find additional operators to those that have appeared in the literature at dimension 7 (specifically in the case of more than one fermion generation) and at dimension 8. (The title sequence is the total number of independent operators in the SM EFT with one fermion generation, including hermitian conjugates, ordered in mass dimension, starting at dimension 5.)

scholarly journals Long-lived heavy neutral leptons at the LHC: four-fermion single-NR operators

2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Rebeca Beltrán ◽  
Giovanna Cottin ◽  
Juan Carlos Helo ◽  
Martin Hirsch ◽  
Arsenii Titov ◽  
...  
Keyword(s):  
Field Theory ◽  
Standard Model ◽  
Effective Field Theory ◽  
New Physics ◽  
Effective Field ◽  
High Luminosity ◽  
The Past ◽  
The Standard Model ◽  
Model Independent

Abstract Interest in searches for heavy neutral leptons (HNLs) at the LHC has increased considerably in the past few years. In the minimal scenario, HNLs are produced and decay via their mixing with active neutrinos in the Standard Model (SM) spectrum. However, many SM extensions with HNLs have been discussed in the literature, which sometimes change expectations for LHC sensitivities drastically. In the NRSMEFT, one extends the SM effective field theory with operators including SM singlet fermions, which allows to study HNL phenomenology in a “model independent” way. In this paper, we study the sensitivity of ATLAS to HNLs in the NRSMEFT for four-fermion operators with a single HNL. These operators might dominate both production and decay of HNLs, and we find that new physics scales in excess of 20 TeV could be probed at the high-luminosity LHC.

scholarly journals Exclusion Limits on a Scalar Decaying to Photons and Distinguishing Its Production Mechanisms

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Tanumoy Mandal
Keyword(s):  
Cross Sections ◽  
Effective Field Theory ◽  
Gluon Fusion ◽  
Effective Field ◽  
Beyond The Standard Model ◽  
Theory Approach ◽  
The Standard Model ◽  
Resonance Search ◽  
Model Independent ◽  
Production Mechanisms

LHC run-II has a great potential to search for new resonances in the diphoton channel. Latest 13 TeV data already put stringent limits on the cross sections in the diphoton channel assuming the resonance is produced through the gluon-gluon fusion. Many beyond the Standard Model (SM) theories predict TeV-scale scalars, which copiously decay to diphotons. Apart from the gluon-gluon fusion production, these scalars can also be dominantly produced in other ways too at the LHC, namely, through the quark-quark fusion or the gauge boson fusions like the photon-photon, photon-Z, WW, or ZZ fusions. In this paper we use an effective field theory approach where a heavy scalar can be produced in various ways and recast the latest ATLAS diphoton resonance search to put model-independent limits on its mass and effective couplings to the SM particles. If a new scalar is discovered at the LHC, it would be very important to identify its production mechanism in order to probe the nature of the underlying theory. We show that combining various kinematic variables in a multivariate analysis can be very powerful to distinguish different production mechanisms from one another.

scholarly journals Sensitivity to BSM effects in the Higgs pT spectrum within SMEFT

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Marco Battaglia ◽  
Massimiliano Grazzini ◽  
Michael Spira ◽  
Marius Wiesemann
Keyword(s):  
Top Quark ◽  
Gluon Fusion ◽  
Effective Field ◽  
Three Dimension ◽  
Linear Quadratic ◽  
Effective Coupling ◽  
Dipole Operator ◽  
The Standard Model ◽  
Light Scalar ◽  
Scalar Top

Abstract The study of Higgs boson production at large transverse momentum is one of the new frontiers for the LHC Higgs physics programme. This paper considers boosted Higgs production in the Standard Model Effective Field Theory (SMEFT). We focus on the gluon fusion and t$$ \overline{t} $$ t ¯ H production processes and study the effects of three dimension-6 operators: the top Yukawa operator, the gluon-Higgs effective coupling and the chromomagnetic dipole operator of the top quark. We perform a detailed study of the sensitivity of current and future LHC data to the corresponding Wilson coefficients, consistently accounting for their renormalisation group evolution. We compare the sensitivities obtained with only linear and linear + quadratic terms in the SMEFT by using the spectrum shape and the addition of the Higgs signal yields. We also consider fits of pT spectra in models with heavy-top partners and in MSSM scenarios with a light scalar top and study the validity of the SMEFT assumptions as a function of the new-particle masses and the Higgs pT range. Finally, we extract constraints on the Wilson coefficients for gluon fusion from a simultaneous fit to the ATLAS and CMS data and compare our results with those obtained in global SMEFT analyses.

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