H2020Индивидуална стипендия2019–2021

LightBosons · Search for Higgs boson decays into Light Bosons in Boosted Hadronic final states

„Хоризонт 2020“ — Действия „Мария Склодовска-Кюри“

Период: 2019-05-01 → 2021-04-30
Финансиране от ЕС: 224 934 €
Участници: 1
Схема: MSCA-IF-EF-ST

Линиите свързват координатора с партньорите.

Накратко на български

Разпадите на Хигс бозона върху Z бозон и непознат лек неутрален бозон се търсят чрез данни от Големия адронен колайдер. Търсенето помага за разбирането на тъмната материя и произхода на масата на частиците, които стандартният модел на физиката не обяснява.

Този кратък обзор е генериран от изкуствен интелект

Кратко обяснение, генерирано от езиков модел по текста на CORDIS. Оригиналът е по-долу.

Резултати накратко

Search for Higgs boson decays into Light Bosons in Boosted Hadronic final states

The goal of this project was to search for new beyond the Standard Model (SM) physics in the Higgs sector, through a novel search for anomalous decays of the Higgs boson into a Z boson and an undiscovered light neutral boson. The necessity for such new physics is motivated by several fundamental questions, such as the unexplained nature of the dark matter, that corresponds to 85% of the matter of the universe, and the origin of the fermion mass hierarchy, which spans several orders of magnitude in mass. The SM offers no explanations for these important questions. Several ideas put forward to explain these puzzles, such as those involving extended Higgs sectors, also predict the existence of new light neutral bosons, often denoted a. Such bosons are expected to be produced in the decays of the observed Higgs boson, either in pairs, H -> aa, or in association with a Z boson, H -> Za. While the H -> aa channel had been searched for at the LHC, until the completion of this project, the H -> Za channel represented a highly viable yet largely under-investigated probe of potential new physics in the Higgs sector requiring urgent attention. In this project a direct search was performed for the the H -> Za decay with proton-proton collision data collected by the ATLAS experiment during Run 2 of the CERN Large Hadron Collider. The experimental strategy was designed to maximise the sensitivity by targeting boosted hadronic decays of the a boson. This goal was achieved by the development of several novel tools. No excess of events over the expected background was found, and an upper limit on the fraction of these potential decays of the Higgs boson of around 30% was set at 95% confidence level. The results of this seminal study were published in Phys. Rev. Lett. 125 (2020) 22 (arXiv:2004.01678).

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз

Цел на проекта

The observation and characterisation of the Higgs boson represents the culmination of over forty years of experimental and theoretical progress, cementing the Standard Model (SM) as the most successful fundamental physical theory to date. However, many open questions still remain which can only be addressed with the new physics predicted by many beyond the SM (BSM) theories. Many such theories, such as two Higgs doublet models and the next Next-to-Minimal Supersymmetric Standard Model, also predict new light bosons or an extended Higgs sector. The observation of the Higgs boson opens a new window to search for such new particles, denoted a. This project aims to observe the production of new light hadronically decaying bosons in the Higgs boson decays h->Za, focusing on h->Za->ll+hadrons final states. This is breaking new ground as the h-> Za channel is entirely uncharted territory, only recently proposed, which will probe large parts of the currently allowed 2HDM parameter space. These searches have been out-of-reach to-date due to the challenge of reconstructing low-mass boosted hadronic objects. The exploitation of these channels will require significant innovations such as the development of new reconstruction techniques for boosted low mass hadronic resonances. Looking to the future the upgrade of the ATLAS Inner Tracker is of paramount importance to fully exploit the physics potential of this project with the High Luminosity LHC. The results of this project will represent an important step towards understanding the extent of the Higgs sector or lead to a revolutionary discovery, the first observation of BSM physics at the LHC.

Оригинален текст от CORDIS (на английски).

Участници

THE UNIVERSITY OF BIRMINGHAM · BirminghamКоординаторОбединеното кралство