Editorial

3 pages, 177 KiB

Open AccessEditorial

Higher Order Radiative Corrections in QCD

by Zoltán Trócsányi, Adam Kardos and Giuseppe Bevilacqua

Symmetry 2022, 14(1), 41; https://0-doi-org.brum.beds.ac.uk/10.3390/sym14010041 - 29 Dec 2021

Viewed by 830

The spectacular physics results collected during the first two runs of the Large Hadron Collider (LHC) present compelling evidence that the Standard Model of Particle Physics describes nature with a very high degree of accuracy [...] Full article

(This article belongs to the Special Issue Higher Order Radiative Corrections in QCD)

Research

Jump to: Editorial

13 pages, 624 KiB

Open AccessArticle

Production of the Doubly Charged Higgs Boson in Association with the SM Gauge Bosons and/or Other HTM Scalars at Hadron Colliders

by Bartosz Dziewit, Magdalena Kordiaczyńska and Tripurari Srivastava

Symmetry 2021, 13(7), 1240; https://0-doi-org.brum.beds.ac.uk/10.3390/sym13071240 - 10 Jul 2021

Cited by 4 | Viewed by 1751

Abstract

We investigate an extension of the Standard Model with one additional triplet of scalar bosons. Altogether, the model contains four Higgs bosons. We analyze the associated production of the doubly charged scalar with the Standard Model gauge bosons and the remaining Higgs bosons [...] Read more.

We investigate an extension of the Standard Model with one additional triplet of scalar bosons. Altogether, the model contains four Higgs bosons. We analyze the associated production of the doubly charged scalar with the Standard Model gauge bosons and the remaining Higgs bosons of the model, which are: the light (SM) and heavy neutral scalars and a singly charged scalar. We estimate, in the context of the present (HL–LHC) and future (FCC–hh) hadron colliders, the most promising processes in which a single produced doubly charged Higgs boson is involved. Full article

(This article belongs to the Special Issue Higher Order Radiative Corrections in QCD)

► Show Figures

Figure 1

11 pages, 836 KiB

Open AccessArticle

Learning Latent Jet Structure

by Barry M. Dillon, Darius A. Faroughy, Jernej F. Kamenik and Manuel Szewc

Symmetry 2021, 13(7), 1167; https://0-doi-org.brum.beds.ac.uk/10.3390/sym13071167 - 29 Jun 2021

Cited by 4 | Viewed by 1351

Abstract

We summarize our recent work on how to infer on jet formation processes directly from substructure data using generative statistical models. We recount in detail how to cast jet substructure observables’ measurements in terms of Bayesian mixed membership models, in particular Latent Dirichlet [...] Read more.

We summarize our recent work on how to infer on jet formation processes directly from substructure data using generative statistical models. We recount in detail how to cast jet substructure observables’ measurements in terms of Bayesian mixed membership models, in particular Latent Dirichlet Allocation. Using a mixed sample of QCD and boosted

t \bar{t}

jet events and focusing on the primary Lund plane observable basis for event measurements, we show how using educated priors on the latent distributions allows to infer on the underlying physical processes in a semi-supervised way. Full article

(This article belongs to the Special Issue Higher Order Radiative Corrections in QCD)

► Show Figures

Figure 1

24 pages, 382 KiB

Open AccessArticle

Top–Bottom Condensation Model: Symmetries and Spectrum of the Induced 2HDM

by Alexander A. Osipov, Brigitte Hiller, Alex H. Blin and Marcos Sampaio

Symmetry 2021, 13(7), 1130; https://0-doi-org.brum.beds.ac.uk/10.3390/sym13071130 - 24 Jun 2021

Cited by 1 | Viewed by 1386

Abstract

Here, we use the Schwinger–DeWitt approach to address the four-fermion composite Higgs effective model proposed by Miransky, Tanabashi and Yamawaki (MTY). The surprising benefit of such an approach is that it is possible to ascribe to a SM-type Higgs a quark–antiquark structure of [...] Read more.

Here, we use the Schwinger–DeWitt approach to address the four-fermion composite Higgs effective model proposed by Miransky, Tanabashi and Yamawaki (MTY). The surprising benefit of such an approach is that it is possible to ascribe to a SM-type Higgs a quark–antiquark structure of predominantly a

\bar{b} b

nature with a small

\bar{t} t

admixture, which in turn yields a Higgs mass compatible with the observed value of 125 GeV. We discuss this result in a detailed and pedagogical way, as it goes against the common belief that this model and akin composite descriptions should predict a Higgs mass-of-order of twice the top quark mass, contrary to empirical evidence. A further aspect of this approach is that it highlights the link of the

S U {(2)}_{L} \times U {(1)}_{R}

symmetric four-fermion MTY model interactions of the heavy quark family to a specific two-Higgs-doublet model (2HDM), and the necessity to go beyond the one Higgs doublet to obtain the empirical Higgs mass within composite models. By appropriately fixing the symmetry-defining interaction parameters, we show that the resulting CP-preserving spectrum harbors the following collective states at the electroweak scale

Λ_{E W} = 246

GeV: a light scalar to which the standard Higgs is associated; a heavier neutral state preconized as the Nambu partner of the standard Higgs within the Nambu sum rule; the expected triplet of Goldstone bosons associated with the longitudinal polarizations of the electroweak massive bosons; and a neutral pseudoscalar state that in the limit of a global

U {(1)}_{A}

symmetry would be a Goldstone mode. The anomalous breaking of this axial symmetry is a subleading effect in a large

N_{c}

counting scheme, and we discuss how it modifies the leading-order Nambu sum rule result and its relevance for the qualitative description of the spectrum. Full article

(This article belongs to the Special Issue Higher Order Radiative Corrections in QCD)

22 pages, 1316 KiB

Open AccessArticle

Optimized Probes of the CP Nature of the Top Quark Yukawa Coupling at Hadron Colliders

by Darius A. Faroughy, Blaž Bortolato, Jernej F. Kamenik, Nejc Košnik and Aleks Smolkovič

Symmetry 2021, 13(7), 1129; https://0-doi-org.brum.beds.ac.uk/10.3390/sym13071129 - 24 Jun 2021

Cited by 2 | Viewed by 1312

Abstract

We summarize our recent proposals for probing the

C P

-odd

i \tilde{κ} \bar{t} γ^{5} t h

interaction at the LHC and its projected upgrades directly using associated on-shell Higgs boson and top quark or top quark pair production. We [...] Read more.

We summarize our recent proposals for probing the

C P

-odd

i \tilde{κ} \bar{t} γ^{5} t h

interaction at the LHC and its projected upgrades directly using associated on-shell Higgs boson and top quark or top quark pair production. We first recount how to construct a

C P

-odd observable based on top quark polarization in

W b \to t h

scattering with optimal linear sensitivity to

\tilde{κ}

. For the corresponding hadronic process

p p \to t h j

we then present a method of extracting the phase-space dependent weight function that allows to retain close to optimal sensitivity to

\tilde{κ}

. For the case of top quark pair production in association with the Higgs boson,

p p \to t \bar{t} h

, with semileptonically decaying tops, we instead show how one can construct manifestly

C P

-odd observables that rely solely on measuring the momenta of the Higgs boson and the leptons and b-jets from the decaying tops without having to distinguish the charge of the b-jets. Finally, we introduce machine learning (ML) and non-ML techniques to study the phase-space optimization of such

C P

-odd observables. We emphasize a simple optimized linear combination

α \cdot ω

that gives similar sensitivity as the studied fully fledged ML models. Using

α \cdot ω

we review sensitivity projections to

\tilde{κ}

at HL-LHC, HE-LHC, and FCC-hh. Full article

(This article belongs to the Special Issue Higher Order Radiative Corrections in QCD)

► Show Figures

Figure 1

37 pages, 1731 KiB

Open AccessFeature PaperArticle

A Stroll through the Loop-Tree Duality

by José de Jesús Aguilera-Verdugo, Félix Driencourt-Mangin, Roger José Hernández-Pinto, Judith Plenter, Renato Maria Prisco, Norma Selomit Ramírez-Uribe, Andrés Ernesto Rentería-Olivo, Germán Rodrigo, German Sborlini, William Javier Torres Bobadilla and Francesco Tramontano

Symmetry 2021, 13(6), 1029; https://0-doi-org.brum.beds.ac.uk/10.3390/sym13061029 - 08 Jun 2021

Cited by 23 | Viewed by 2604

Abstract

The Loop-Tree Duality (LTD) theorem is an innovative technique to deal with multi-loop scattering amplitudes, leading to integrand-level representations over a Euclidean space. In this article, we review the last developments concerning this framework, focusing on the manifestly causal representation of multi-loop Feynman [...] Read more.

The Loop-Tree Duality (LTD) theorem is an innovative technique to deal with multi-loop scattering amplitudes, leading to integrand-level representations over a Euclidean space. In this article, we review the last developments concerning this framework, focusing on the manifestly causal representation of multi-loop Feynman integrals and scattering amplitudes, and the definition of dual local counter-terms to cancel infrared singularities. Full article

(This article belongs to the Special Issue Higher Order Radiative Corrections in QCD)

► Show Figures

Figure 1

17 pages, 1659 KiB

Open AccessArticle

Exploring QED Effects to Diphoton Production at Hadron Colliders

by Leandro Cieri and German Sborlini

Symmetry 2021, 13(6), 994; https://0-doi-org.brum.beds.ac.uk/10.3390/sym13060994 - 02 Jun 2021

Cited by 4 | Viewed by 1738

Abstract

In this article, we report phenomenological studies about the impact of

O (α)

corrections to diphoton production at hadron colliders. We explore the application of the Abelianized version of the

q_{T}

-subtraction method to efficiently compute NLO QED contributions, taking [...] Read more.

In this article, we report phenomenological studies about the impact of

O (α)

corrections to diphoton production at hadron colliders. We explore the application of the Abelianized version of the

q_{T}

-subtraction method to efficiently compute NLO QED contributions, taking advantage of the symmetries relating QCD and QED corrections. We analyze the experimental consequences due to the selection criteria and we find percent-level deviations for

M_{γ γ} > 1 TeV

. An accurate description of the tail of the invariant mass distribution is very important for new physics searches which have the diphoton process as one of their main backgrounds. Moreover, we emphasize the importance of properly dealing with the observable photons by reproducing the experimental conditions applied to the event reconstruction. Full article

(This article belongs to the Special Issue Higher Order Radiative Corrections in QCD)

► Show Figures

Figure 1

29 pages, 1453 KiB

Open AccessEditor’s ChoiceArticle

IDM Benchmarks for the LHC and Future Colliders

by Jan Kalinowski, Tania Robens, Dorota Sokołowska and Aleksander Filip Żarnecki

Symmetry 2021, 13(6), 991; https://0-doi-org.brum.beds.ac.uk/10.3390/sym13060991 - 02 Jun 2021

Cited by 32 | Viewed by 2579

Abstract

We present cross-section expectations for various processes and collider options, for benchmark scenarios of the Inert Doublet Model, a Two Higgs Doublet Model with a dark matter candidate. The proposed scenarios are consistent with current dark matter constraints, including the most recent bounds [...] Read more.

We present cross-section expectations for various processes and collider options, for benchmark scenarios of the Inert Doublet Model, a Two Higgs Doublet Model with a dark matter candidate. The proposed scenarios are consistent with current dark matter constraints, including the most recent bounds from the XENON1T experiment and relic density, as well as with known collider and low-energy limits. These benchmarks, chosen in earlier work for studies at

e^{+} e^{-}

colliders, exhibit a variety of kinematic features that should be explored at current and future runs of the LHC. We provide cross sections for all relevant production processes at 13 TeV, 27 TeV and 100 TeV proton collider, as well as for a possible 10 TeV and 30 TeV muon collider. Full article

(This article belongs to the Special Issue Higher Order Radiative Corrections in QCD)

► Show Figures

Figure 1

22 pages, 633 KiB

Open AccessArticle

A Brief Review of Implicit Regularization and Its Connection with the BPHZ Theorem

by Dafne Carolina Arias-Perdomo, Adriano Cherchiglia, Brigitte Hiller and Marcos Sampaio

Symmetry 2021, 13(6), 956; https://0-doi-org.brum.beds.ac.uk/10.3390/sym13060956 - 27 May 2021

Cited by 8 | Viewed by 2031

Abstract

Quantum Field Theory, as the keystone of particle physics, has offered great insights into deciphering the core of Nature. Despite its striking success, by adhering to local interactions, Quantum Field Theory suffers from the appearance of divergent quantities in intermediary steps of the [...] Read more.

Quantum Field Theory, as the keystone of particle physics, has offered great insights into deciphering the core of Nature. Despite its striking success, by adhering to local interactions, Quantum Field Theory suffers from the appearance of divergent quantities in intermediary steps of the calculation, which encompasses the need for some regularization/renormalization prescription. As an alternative to traditional methods, based on the analytic extension of space–time dimension, frameworks that stay in the physical dimension have emerged; Implicit Regularization is one among them. We briefly review the method, aiming to illustrate how Implicit Regularization complies with the BPHZ theorem, which implies that it respects unitarity and locality to arbitrary loop order. We also pedagogically discuss how the method complies with gauge symmetry using one- and two-loop examples in QED and QCD. Full article

(This article belongs to the Special Issue Higher Order Radiative Corrections in QCD)

► Show Figures

Figure 1

10 pages, 3048 KiB

Open AccessArticle

Analysis of the Internal Structure of Hadrons Using Direct Photon Production

by David Francisco Rentería-Estrada, Roger José Hernández-Pinto and German Sborlini

Symmetry 2021, 13(6), 942; https://0-doi-org.brum.beds.ac.uk/10.3390/sym13060942 - 26 May 2021

Cited by 6 | Viewed by 2022

Abstract

Achieving a precise description of the internal structure of hadrons is crucial for deciphering the hidden properties and symmetries of fundamental particles. It is a hard task since there are several bottlenecks in obtaining theoretical predictions starting from first principles. In order to [...] Read more.

Achieving a precise description of the internal structure of hadrons is crucial for deciphering the hidden properties and symmetries of fundamental particles. It is a hard task since there are several bottlenecks in obtaining theoretical predictions starting from first principles. In order to complement highly accurate experiments, it is necessary to use ingenious strategies to impose constraints from the theory side. In this article, we describe how photons can be used to unveil the internal structure of hadrons. We explore how to describe NLO QCD plus LO QED corrections to hadron plus photon production at colliders and discuss the impact of these effects on the experimental measurements. Full article

(This article belongs to the Special Issue Higher Order Radiative Corrections in QCD)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Higher Order Radiative Corrections in QCD

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (10 papers)

Editorial

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI