scholarly journals Measuring Higgs boson self-couplings with 2 → 3 VBS processes

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Junmou Chen ◽  
Chih-Ting Lu ◽  
Yongcheng Wu
Keyword(s):  
Higgs Boson ◽  
Cross Sections ◽  
Effective Field Theory ◽  
Vector Boson ◽  
Effective Field ◽  
Low Energy ◽  
Final States ◽  
Lepton Colliders ◽  
Vector Boson Scattering ◽  
Muon Colliders

Abstract We study the measurement of Higgs boson self-couplings through 2 → 3 vector boson scattering (VBS) processes in the framework of Standard Model effective field theory (SMEFT) at both proton and lepton colliders. The SMEFT contribution to the amplitude of the 2 → 3 VBS processes, taking WLWL → WLWLh and WLWL → hhh as examples, exhibits enhancement with the energy $$ \frac{{\mathcal{A}}^{\mathrm{BSM}}}{{\mathcal{A}}^{\mathrm{SM}}}\sim \frac{E^2}{\Lambda^2} $$ A BSM A SM ~ E 2 Λ 2 , which indicates the sensitivity of these processes to the related dimension-six operators in SMEFT. Simulation of the full processes at both hadron and lepton colliders with a variety of collision energies are performed to estimate the allowed region on c6 and $$ {c}_{\Phi_1} $$ c Φ 1 . Especially we find that, with the help of exclusively choosing longitudinal polarizations in the final states and suitable pT cuts, WWh process is as important as the more widely studied triple Higgs production (hhh) in the measurement of Higgs self-couplings. Our analysis indicates that these processes can play important roles in the measurement of Higgs self-couplings at future 100 TeV pp colliders and muon colliders. However, their cross sections are generally tiny at low energy machines, which makes them much more challenging to explore.

scholarly journals SMEFT analysis of vector boson scattering and diboson data from the LHC Run II

2021 ◽  
Vol 81 (6) ◽  
Author(s):  
Jacob J. Ethier ◽  
Raquel Gomez-Ambrosio ◽  
Giacomo Magni ◽  
Juan Rojo
Keyword(s):  
Field Theory ◽  
Cross Sections ◽  
Effective Field Theory ◽  
Particle Physics ◽  
Vector Boson ◽  
Effective Field ◽  
High Luminosity ◽  
Complementary Information ◽  
Electroweak Sector ◽  
Vector Boson Scattering

AbstractWe present a systematic interpretation of vector boson scattering (VBS) and diboson measurements from the LHC in the framework of the dimension-six standard model effective field theory (SMEFT). We consider all available measurements of VBS fiducial cross-sections and differential distributions from ATLAS and CMS, in most cases based on the full Run II luminosity, and use them to constrain 16 independent directions in the dimension-six EFT parameter space. Compared to the diboson measurements, we find that VBS provides complementary information on several of the operators relevant for the description of the electroweak sector. We also quantify the ultimate EFT reach of VBS measurements via dedicated projections for the high luminosity LHC. Our results motivate the integration of VBS processes in future global SMEFT interpretations of particle physics data.

scholarly journals Vector boson fusion at multi-TeV muon colliders

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Antonio Costantini ◽  
Federico De Lillo ◽  
Fabio Maltoni ◽  
Luca Mantani ◽  
Olivier Mattelaer ◽  
...  
Keyword(s):  
Cross Sections ◽  
Vector Boson ◽  
High Energy ◽  
New Physics ◽  
Vector Boson Fusion ◽  
Weak Boson ◽  
Wide Range ◽  
Lepton Colliders ◽  
Muon Colliders ◽  
New Phenomena

Abstract High-energy lepton colliders with a centre-of-mass energy in the multi-TeV range are currently considered among the most challenging and far-reaching future accelerator projects. Studies performed so far have mostly focused on the reach for new phenomena in lepton-antilepton annihilation channels. In this work we observe that starting from collider energies of a few TeV, electroweak (EW) vector boson fusion/scattering (VBF) at lepton colliders becomes the dominant production mode for all Standard Model processes relevant to studying the EW sector. In many cases we find that this also holds for new physics. We quantify the size and the growth of VBF cross sections with collider energy for a number of SM and new physics processes. By considering luminosity scenarios achievable at a muon collider, we conclude that such a machine would effectively be a “high-luminosity weak boson collider,” and subsequently offer a wide range of opportunities to precisely measure EW and Higgs couplings as well as discover new particles.

scholarly journals Extending low energy effective field theory with a complete set of dimension-7 operators

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Yi Liao ◽  
Xiao-Dong Ma ◽  
Quan-Yu Wang
Keyword(s):  
Field Theory ◽  
Standard Model ◽  
Cross Sections ◽  
Effective Field Theory ◽  
Degrees Of Freedom ◽  
Independent Set ◽  
Effective Field ◽  
Low Energy ◽  
Tree Level ◽  
The Standard Model

Abstract We present a complete and independent set of dimension-7 operators in the low energy effective field theory (LEFT) where the dynamical degrees of freedom are the standard model five quarks and all of the neutral and charged leptons. All operators are non-Hermitian and are classified according to their baryon (∆B) and lepton (∆L) numbers violated. Including Hermitian-conjugated operators, there are in total 3168, 750, 588, 712 operators with (∆B, ∆L) = (0, 0), (0, ±2), (±1, ∓1), (±1, ±1) respectively. We perform the tree-level matching with the standard model effective field theory (SMEFT) up to dimension-7 (dim-7) operators in both LEFT and SMEFT. As a phenomenological application we study the effective neutrino-photon interactions due to dim-7 lepton number violating operators that are induced and much enhanced at one loop from dim-6 operators that in turn are matched from dim-7 SMEFT operators. We compare various neutrino-photon scattering cross sections with their counterparts in the standard model and highlight the new features. Finally, we illustrate how these effective interactions could arise from ultraviolet completion.

scholarly journals Effective Field Theory and Unitarity in Vector Boson Scattering

2016 ◽  
Author(s):  
Marco Sekulla ◽  
Wolfgang Kilian ◽  
Thorsten Ohl ◽  
Jürgen Reuter
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Vector Boson ◽  
Effective Field ◽  
Vector Boson Scattering

scholarly journals DsixTools 2.0: the effective field theory toolkit

2021 ◽  
Vol 81 (2) ◽  
Author(s):  
Javier Fuentes-Martín ◽  
Pedro Ruiz-Femenía ◽  
Avelino Vicente ◽  
Javier Virto
Keyword(s):  
Field Theory ◽  
Renormalization Group ◽  
Cross Sections ◽  
Effective Field Theory ◽  
Degrees Of Freedom ◽  
Effective Field ◽  
Low Energy ◽  
Weak Basis ◽  
The Standard Model ◽  
Group Evolution

Abstract is a package for the handling of the standard model effective field theory (SMEFT) and the low-energy effective field theory (LEFT) with operators up to dimension six, both at the algebraic and numerical level. contains a visually accessible and operationally convenient repository of all operators and parameters of the SMEFT and the LEFT. This repository also provides information concerning symmetry categories and number of degrees of freedom, and routines that allow to implement this information on global expressions (such as decay amplitudes and cross-sections). also performs weak basis transformations, and implements the full one-loop Renormalization Group Evolution in both EFTs (with SM beta functions up to five loops in QCD), and the full one-loop SMEFT-LEFT matching at the electroweak scale.

scholarly journals Effective field theory versus UV-complete model: vector boson scattering as a case study

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Jannis Lang ◽  
Stefan Liebler ◽  
Heiko Schäfer-Siebert ◽  
Dieter Zeppenfeld
Keyword(s):  
Cross Sections ◽  
Vector Boson ◽  
High Energy ◽  
Effective Field ◽  
Threshold Region ◽  
Validity Range ◽  
Theory Versus ◽  
Bsm Physics ◽  
Vector Boson Scattering

AbstractEffective field theories (EFT) are commonly used to parameterize effects of BSM physics in vector boson scattering (VBS). For Wilson coefficients which are large enough to produce presently observable effects, the validity range of the EFT represents only a fraction of the energy range covered by the LHC, however. In order to shed light on possible extrapolations into the high energy region, a class of UV-complete toy models, with extra SU(2) multiplets of scalars or of fermions with vector-like weak couplings, is considered. By calculating the Wilson coefficients up to energy-dimension eight, and full one-loop contributions to VBS due to the heavy multiplets, the EFT approach, with and without unitarization at high energy, is compared to the perturbative prediction. For high multiplicities, e.g. nonets of fermions, the toy models predict sizable effects in transversely polarized VBS, but only outside the validity range of the EFT. At lower energies, dimension-eight operators are needed for an adequate description of the models, providing another example that dimension-eight can be more important than dimension-six operators. A simplified VBFNLO implementation is used to estimate sensitivity of VBS to such BSM effects at the LHC. Unitarization captures qualitative features of the toy models at high energy but significantly underestimates signal cross sections in the threshold region of the new particles.

scholarly journals Search for heavy resonances decaying into a vector boson and a Higgs boson in final states with charged leptons, neutrinos, and b quarks

2017 ◽  
Vol 768 ◽  
pp. 137-162 ◽  
Author(s):  
V. Khachatryan ◽  
A.M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
E. Asilar ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Vector Boson ◽  
Final States ◽  
B Quarks ◽  
Heavy Resonances ◽  
Charged Leptons

scholarly journals Studies of Deuteron–Proton Collisions at 100 MeV

2021 ◽  
Vol 62 (4) ◽  
Author(s):  
I. Skwira-Chalot ◽  
N. Kalantar-Nayestanaki ◽  
St. Kistryn ◽  
A. Kozela ◽  
E. Stephan
Keyword(s):  
Cross Section ◽  
Effective Field Theory ◽  
Beam Energy ◽  
Effective Field ◽  
Breakup Reaction ◽  
Low Energy ◽  
Chiral Effective Field Theory ◽  
Proton Collisions ◽  
Realistic Potentials ◽  
Good Agreement

AbstractDifferential cross section for the $$^1H(d,pp)n$$ 1 H ( d , p p ) n reaction is sensitive to various dynamical ingredients and allows for thorough tests of theoretical potentials describing the interaction in the three nucleon systems. The analysis of the experimental data collected for the breakup reaction at the beam energy of 100 MeV has been performed and the first cross section results for selected configurations are presented in this paper. They are in good agreement with calculations based on the realistic potentials. Studies at this relatively low energy will also be important for examining awaited calculations within the Chiral Effective Field Theory.

scholarly journals Observation of ZZ production via Vector Boson Scattering in ATLAS

2021 ◽  
Vol 2105 (1) ◽  
pp. 012013
Author(s):  
Ioannis Maznas
Keyword(s):  
Cross Sections ◽  
Vector Boson ◽  
Statistical Significance ◽  
Signal Strength ◽  
Atlas Detector ◽  
Pp Collisions ◽  
Final State ◽  
Measurement Results ◽  
Vector Boson Scattering

Abstract This document presents measurement results of the ZZ production via Vector Boson Scattering interactions in 139fb −1 of data recorded by the ATLAS detector from pp collisions at s = 13 TeV during LHC Run-II (2015-2018). In this study, 127 candidate events with a fully leptonic final state (ℓℓℓℓjj) have been observed and another 82 events for ℓℓvvjj final state, with a contribution of the purely electroweak ZZjj process estimated to be 20.6 ± 2.5 and 12.3 ± 0.7 events respectively. The measured cross sections were found to be 1.27 ± 0.14fb (1.22 ± 0.35fb) for ℓℓℓℓjj (ℓℓvvjj) in their respective fiducial regions. Using multivariant methods, the EW production of ZZjj events (combining the ℓℓℓℓjj and ℓℓvvjj channels) was measured to have a signal strength of 1.35± 0.34, which leads to a rejection of the no-electroweak hypothesis with a statistical significance of 5.5σ.

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