Discovery Of The Higgs Boson Research Articles

Converting the Literature of a Scientific Field to Open Access through Global Collaboration: The Experience of SCOAP3 in Particle Physics

Gigantic particle accelerators, incredibly complex detectors, an antimatter factory and the discovery of the Higgs boson—this is part of what makes CERN famous. Only a few know that CERN also hosts the world largest Open Access initiative: SCOAP3. The Sponsoring Consortium for Open Access Publishing in Particle Physics started operation in 2014 and has since supported the publication of 20,000 Open Access articles in the field of particle physics, at no direct cost, nor burden, for individual authors worldwide. SCOAP3 is made possible by a 3000-institute strong partnership, where libraries re-direct funds previously used for subscriptions to ‘flip’ articles to ‘Gold Open Access’. With its recent expansion, the initiative now covers about 90% of the journal literature of the field. This article describes the economic principles of SCOAP3, the collaborative approach of the partnership, and finally summarizes financial results after four years of successful operation.

Higgs cosmology.

The discovery of the Higgs boson in 2012 and other results from the Large Hadron Collider have confirmed the standard model of particle physics as the correct theory of elementary particles and their interactions up to energies of several TeV. Remarkably, the theory may even remain valid all the way to the Planck scale of quantum gravity, and therefore it provides a solid theoretical basis for describing the early Universe. Furthermore, the Higgs field itself has unique properties that may have allowed it to play a central role in the evolution of the Universe, from inflation to cosmological phase transitions and the origin of both baryonic and dark matter, and possibly to determine its ultimate fate through the electroweak vacuum instability. These connections between particle physics and cosmology have given rise to a new and growing field of Higgs cosmology, which promises to shed new light on some of the most puzzling questions about the Universe as new data from particle physics experiments and cosmological observations become available.This article is part of the Theo Murphy meeting issue 'Higgs cosmology'.

Perspectives in Particle Physics after the Discovery of the Higgs Boson

Many implications of the discovery of the Higgs boson are discussed, together with a short overview of the new challenges in particle physics. The paper also presents a non-exhaustive review of the current plans in the quest for physics beyond the Standard Model at high-energy accelerators.

Physics After the Discovery of the Higgs Boson

I show that with the discovery of the Higgs boson we have entered a new phase of our understanding of nature. This leads us towards a paradigm shift in the search for possible new physics, away from major extensions like supersymmetry towards minimalistic extensions, that largely preserve the structure of the standard model. To discover such new physics, precision may be more important than energy. Precision = Discovery! A possible path for the future is sketched.

Searches for Supersymmetry in ATLAS

After the discovery of the Higgs boson in ATLAS first run of data taking, and due to the lack of observation of new physics, searches for new particles such as Supersymmetric states are one of the main area of interest for the general purpose detectors operating at LHC. In this talk we will present a review of the searches for Supersymmetric particles, performed by the ATLAS experiment

The origin of particle masses and the naturalness problem

Electroweak symmetry breaking is the key ingredient of the standard model responsible for the generation of all elementary particle masses. The discovery of the Higgs boson is a major milestone towards understanding the mechanism of electroweak symmetry breaking but several important issues remain unexplained. Among them the key mystery is how to stabilize the electroweak symmetry scale, called the naturalness problem. To solve this problem, some new physics should be introduced to screen quantum corrections from higher energy scale. There are two classes of new physics theories: one is super symmetry model in which Higgs quadratic divergence is cancelled through the extended space-time symmetry between scalars and fermions. The other one is composite Higgs model in which the sensitivity to higher energy scale is reduced by the composite nature of Higgs. In super symmetry model, every field in standard model should have a super symmetric partner, which makes this theory very complicated. However, the composite Higgs models can address the naturalness problem in a very simple way. In this article we first review the Higgs mechanism in standard model and explain Higgs naturalness problem. Then we generally review the super symmetry model and its phenomenology. It is found that the tuning of this kind of model is worse than 1% when confronts experimental measurements. In the remaining parts we focus on discussing the composite Higgs model. We first review the structure of composite Higgs models and then discuss how to reduce Higgs mass through some symmetry collectively breaking or extra dimension mechanism. It is found that, in this kind of models, to produce a light Higgs the composite quarks canceling Higgs quadratic divergences should be relatively light, around 1 TeV. But the constraints from Large Hadron Collider (LHC) indicate that these fermions should be much heavier than 1 TeV, which results the difficulty in achieving a light Higgs. Moreover, to evade precise electroweak tests, the electroweak scale should be separated with Higgs confinement scale, called the Little Hierarchy, requiring more tuning in this model. In order to produce light Higgs while keeping composite quarks heavy, we plan to find a general principle to realize neutral naturalness mechanism in which Higgs quadratic divergences are cancelled by hidden sector. And then find the UV completion for this mechanism and fully study its phenomenology. In order to naturally solve Little Hierarchy, we plan to construct a mechanism to produce Higgs tree level or loop level self-quartic coupling, so that the big separation between electroweak and confinement scale can be achieved by adjusting properly this coupling without introducing any tuning. After solving above two problems, we combine these two mechanisms to construct the super-natural composite Higgs model which can successfully achieve electroweak symmetry breaking without any tuning.

Measurement of cross sections and couplings of the Higgs Boson using the ATLAS detector

After the discovery of the Higgs boson, the measurement of its coupling properties are of particular importance. In this talk measurement of the cross sections and couplings of the Higgs boson in bosonic and fermionic decay channels with the ATLAS detector are presented.

Measurement of cross sections and couplings of the Higgs Boson in bosonic decay channels with the ATLAS detector

After the discovery of the Higgs boson, the measurement of its properties are of particular importance. In this paper, measurement of the cross sections and couplings of the Higgs boson in bosonic decay channels with the ATLAS detector are presented. Previous measurements of the spin and parity of this new particle, as well as the investigation of its couplings to other SM particles, revealed no significant deviations from the corresponding predictions for the Standard Model Higgs boson. In the years 2015-2017, the centre-of-mass energy √s and the integrated luminosity of the Large Hadron Collider was increased up to 13 TeV and 36.1 fb-1, respectively. With this improvements of the LHC, the properties of recently discovered Higgs boson can be studied in more details. In this paper, latest updates on cross sections and couplings analyses of the Higgs Boson are presented. The discussion will focus on the recent results obtained by the ATLAS collaboration in γγ and 4l Higgs boson decay channels as well as their combination.

The SHiP experiment at CERN

The discovery of the Higgs boson has fully confirmed the Standard Model of particles and fields. Nevertheless, there are still fundamental phenomena, like the existence of dark matter and the baryon asymmetry of the Universe, deserving an explanation that could come from the discovery of new particles. Searches for new physics with accelerators are performed at the LHC, looking for high massive particles coupled to matter with ordinary strength. A new experiment at CERN meant to search for very weakly coupled particles in the few GeV mass domain has been recently proposed. The existence of such particles, foreseen in different theoretical models beyond the Standard Model, is largely unexplored. A beam dump facility using high intensity 400 GeV protons is a copious source of such unknown particles in the GeV mass range. The beam dump is also a copious source of neutrinos and in particular it is an ideal source of tau neutrinos, the less known particle in the Standard Model. The neutrino detector can also search for dark matter through its scattering off the electrons. We report the physics potential of the SHiP experiment.

The SHiP physics program

The discovery of the Higgs boson has fully confirmed the Standard Model of particles and fields. Nevertheless, there are still fundamental phenomena, like the existence of dark matter and the baryon asymmetry of the Universe, which deserve an explanation that could come from the discovery of new particles. The SHiP experiment at CERN meant to search for very weakly coupled particles in the few GeV mass domain has been recently proposed. The existence of such particles, foreseen in different theoretical models beyond the Standard Model, is largely unexplored. A beam dump facility using high intensity 400 GeV protons is a copious source of such unknown particles in the GeV mass range. The beam dump is also a copious source of neutrinos and in particular it is an ideal source of tau neutrinos, the less known particle in the Standard Model. Indeed, tau anti-neutrinos have not been directly observed so far. We report the physics potential of such an experiment including the tau neutrino magnetic moment.

A stronger case for superunification post Higgs boson discovery

Supersymmetry and more specifically supergravity grand unification allow one to extrapolate physics from the electroweak scale up to the grand unification scale consistent with electroweak data. Here we give a brief overview of their current status and show that the case for supersymmetry is stronger as a result of the Higgs boson discovery with a mass measurement at ∼125 GeV consistent with the supergravity grand unification prediction that the Higgs boson mass lies below 130 GeV. Thus the discovery of the Higgs boson and the measurement of its mass provide a further impetus for the search for sparticles to continue at the current and future colliders.

Global aspects of the renormalization group and the hierarchy problem

The discovery of the Higgs boson by the ATLAS and CMS collaborations allowed us to precisely determine its mass being 125.09±0.24 GeV. This value is intriguing as it lies at the frontier between the regions of stability and meta-stability of the standard model vacuum. It is known that the hierarchy problem can be interpreted in terms of the near criticality between the two phases. The coefficient of the Higgs bilinear in the scalar potential, m2, is pushed by quantum corrections away from zero, towards the extremes of the interval [−MPl2,MPl2] where MPl is the Planck mass. In this article, I show that demanding topological invariance for the renormalisation group allows us to extend the beta functions such that the particular value of the Higgs mass parameter observed in our universe regains naturalness. In holographic terms, invariance to changes of topology in the bulk is dual to a natural large hierarchy in the boundary quantum field theory. The demand of invariance to topology changes in the bulk appears to be strongly tied to the invariance of string theory to T-duality in the presence of H-fluxes.

High Energy Particle Physics Workshop 2017

PrefaceThe motivation for this workshop began with the discovery of the Higgs boson four years ago, and the realisation that many problems remain in particle physics, such as why there is more matter than anti-matter, better determining the still poorly measured parameters of the strong force, explaining possible sources for dark matter, naturalness etc. While the newly discovered Higgs boson seems to be compatible with the Standard Model, current experimental accuracy is far from providing a definitive statement with regards to the nature of this new particle. There is a lot of room for physics beyond the Standard Model to emerge in the exploration of the Higgs boson. Recent measurements in high-energy heavy ion collisions at the LHC have shed light on the complex dynamics that govern high-density quark-gluon interactions. An array of results from the ALICE collaboration has been highlighted in a recent issue of CERN courier. The physics program of high-energy heavy ion collisions promises to further unveil the intricacies of high-density quark-gluon plasma physics.The great topicality of high energy physics research has also seen a rapid increase in the number of researchers in South Africa pursuing such studies, both experimentally through the ATLAS and ALICE colliders at CERN, and theoretically. Young researchers and graduate students largely populate these research groups, with little experience in presenting their work, and few support structures (to their knowledge) to share experiences with. Whilst many schools and workshops have sought to educate these students on the theories and tools they will need to pursue their research, few have provided them with a platform to present their work. As such, this workshop discussed the various projects being pursued by graduate students and young researchers in South Africa, enabling them to develop networks for future collaboration and discussion.

Mono-Higgs signature in a fermionic dark matter model

In light of the discovery of the Higgs boson we explore a mono-Higgs signature in association with dark matter pair production at the Large Hadron Collider (LHC) in a renormalizable model with a fermionic dark matter candidate. For two channels with γγ+MET and +MET in the final state we simulate the standard model (SM) backgrounds and signal events at TeV. We then estimate the LHC sensitivities for various benchmark points for two integrated luminosities and . We constrain the Yukawa coupling of the dark matter–SM interaction, taking into account bounds from mono-Higgs signature, observed dark matter relic density, Higgs physics, perturbativity requirement and electroweak measurements. Concerning the mono-Higgs search, it turns out that the channel with the largest branching ratio, the channel, provides better sensitivity. There are found regions in the parameter space of the model compatible with all the bounds mentioned above which can be reached in future LHC studies.

Higgs Physics at CMS

The discovery of the Standard Model Higgs boson performed by the CMS and ATLAS collaborations during the LHC Run 1 has been an important success. This document is a short review of the search for the Higgs boson performed by the CMS collaboration during the LHC Run 1 and Run 2. In the first part, after a brief description of the Higgs boson production and decay channels, the Run-1 results are presented emphasizing the possible hints of New Physics. The main part of this document is devoted to the search for the Higgs boson with the 13-TeV data collected by the CMS experiment in 2015 and 2016, including the Standard Model searches as well as the Beyond Standard Model searches, such as the search for additional Higgs bosons and for resonant and non-resonant double Higgs boson production.

The SHiP experiment at CERN

The discovery of the Higgs boson has fully confirmed the Standard Model of particles and fields. Nevertheless, there are still fundamental phenomena, like the existence of dark matter and the baryon asymmetry of the Universe, deserving an explanation that could come from the discovery of new particles. Searches for new physics with accelerators are performed at the LHC, looking for high massive particles coupled to matter with ordinary strength. A new experiment at CERN meant to search for very weakly coupled particles in the few GeV mass domain has been recently proposed. The existence of such particles, foreseen in different theoretical models beyond the Standard Model, is largely unexplored. A beam dump facility using high intensity 400 GeV protons is a copious source of such unknown particles in the GeV mass range. The beam dump is also a copious source of neutrinos and in particular it is an ideal source of tau neutrinos, the less known particle in the Standard Model. The neutrino detector can also search for dark matter through its scattering off the electrons. We report the physics potential of the SHiP experiment.

Cernoises and Horrible Cernettes: a history of women at CERN 1954–2017

ABSTRACTThe European Organisation for Nuclear Research (CERN) was founded in 1954 by a group of men seeking to explore the fundamental building blocks of our Universe. Since then, they and a host of international scholars have succeeded, exemplified by the discovery of the Higgs Boson in 2012 and numerous Nobel Prize awards. But running parallel to the ‘great men’ of high-energy physics, is the untold story of the women of CERN. The organisation is an elite institution, and can thus provide insight into why numbers of women remain low in all facets of its work (except professional administrative). This viewpoint explores the role of women at CERN, both scientists and non-scientists, drawing on archival research from the organisation’s collection in Geneva and interviews, providing an analysis of why gender diversity is still one of the puzzles left for this elite space to solve.

Beyond the hypothesis: Theory's role in the genesis, opposition, and pursuit of the Higgs boson

The centrally recognized theoretical achievement that enabled the Higgs boson discovery in 2012 was the hypothesis of its existence, made by Peter Higgs in 1964. Nevertheless, there is a significant body of comparably important theoretical work prior to and after the Higgs boson hypothesis. In this article we present an additional perspective of how crucial theory work was to the genesis of the Higgs boson hypothesis, especially emphasizing its roots in Landau's theory of phase transitions and subsequent theoretical work on superconductivity. A detailed description is then given of the opposition to the Higgs boson hypothesis by many researchers, giving evidence to its speculative nature. And finally, it is discussed the importance of theory work in the decades after the hypothesis in order to make possible the experimental discovery of the Higgs boson.

Computational Science-based Research on Dark Matter at KISTI

The Standard Model of particle physics was established after discovery of the Higgs boson. However, little is known about dark matter, which has mass and constitutes approximately five times the number of standard model particles in space. The cross-section of dark matter is much smaller than that of the existing Standard Model, and the range of the predicted mass is wide, from a few eV to several PeV. Therefore, massive amounts of astronomical, accelerator, and simulation data are required to study dark matter, and efficient processing of these data is vital. Computational science, which can combine experiments, theory, and simulation, is thus necessary for dark matter research. A computational science and deep learning-based dark matter research platform is suggested for enhanced coverage and sharing of data. Such an approach can efficiently add to our existing knowledge on the mystery of dark matter.

Mixed QCD-electroweak corrections for Higgs boson production at e+e− colliders

Since the discovery of the Higgs boson at the Large Hadron Collider, a future electron-position collider has been proposed for precisely studying its properties. We investigate the production of the Higgs boson at such an $e^+e^-$ collider associated with a $Z$ boson, and calculate for the first time the mixed QCD-electroweak corrections to the total cross sections. We provide an approximate analytic formula for the cross section and show that it reproduces the exact numeric results rather well for collider energies up to 350 GeV. We also provide numeric results for $\sqrt{s}=500$ GeV, where the approximate formula is no longer valid. We find that the $\mathcal{O}(\alpha\alpha_s)$ corrections amount to a 1.3% increase of the cross section for a center-of-mass energy around 240 GeV. This is significantly larger than the expected experimental accuracy and has to be included for extracting the properties of the Higgs boson from the measurements of the cross sections in the future.