Hong Kong Scientists and Students Joined ATLAS Team at LHC, CERN

2015 ◽  
Vol 04 (01) ◽  
pp. 48-49
Author(s):  
Keyword(s):  
Hong Kong ◽  
Higgs Boson ◽  
New Physics ◽  
Atlas Collaboration ◽  
Major Step ◽  
Fundamental Physics ◽  
Fundamental Structure ◽  
Structure Of Matter

A team of physicists from Hong Kong has formally joined the ATLAS Collaboration at CERN since June, 2014. In 2012, the ATLAS Collaboration – along with the CMS Collaboration – co-discovered the Higgs boson. The discovery of the Higgs boson is widely regarded as a major step towards understanding the fundamental structure of matter and other mysteries of our universe. The admission of the Hong Kong team into ATLAS means, all these exciting opportunities of unveiling an era of new breakthroughs in fundamental physics, are now opened up to scientists and students from Hong Kong. The Hong Kong team plans to take up both hardware and software tasks on the muon detecting system and analysis of data to look for new physics.

Scientists and Students from Hong Kong Join a Top Particle Physics Experiment

2014 ◽  
Vol 03 (02) ◽  
pp. 23-24
Author(s):  
Keyword(s):  
Hong Kong ◽  
Higgs Boson ◽  
Particle Physics ◽  
Hadron Collider ◽  
New Physics ◽  
Particle Accelerator ◽  
Atlas Collaboration ◽  
Particle Detectors ◽  
The World ◽  
Physics Experiment

A team of physicists from Hong Kong has now formally joined one of the most prestigious physics experiments in the world. Following a unanimous vote of approval today by its Collaboration Board, ATLAS has admitted the Hong Kong team as a member. The ATLAS Collaboration operates one of the largest particle detectors in the world, located at the Large Hadron Collider (LHC), the world's highest energy particle accelerator at CERN, Switzerland. In 2012, the ATLAS team — along with the CMS Collaboration — co-discovered the Higgs boson, or so-called 'God Particle'. The gigantic but sensitive and precise ATLAS detector, together with the unprecedentedly high collision energy and luminosity of the LHC, make it possible to search for fundamentally new physics, such as dark matter, hidden extra dimensions, and supersymmetry — a proposed symmetry among elementary particles. The LHC is currently undergoing an upgrade, targeting a substantial increase in beam energy and intensity in a year's time. It is widely expected that the discovery of the Higgs boson is only the beginning of an era of new breakthroughs in fundamental physics. All these exciting opportunities are now opened up to scientists and students from Hong Kong.

scholarly journals Highlights from ATLAS

2018 ◽  
Vol 182 ◽  
pp. 02012
Author(s):  
L. Bellagamba
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
New Physics ◽  
Atlas Collaboration ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Pp Collisions ◽  
Ion Collisions

This report presents an overview of some of the most recent results obtained by the ATLAS Collaboration using pp and heavy-ion collisions at the LHC. The review is not intended to be comprehensive and includes recent updates on the Higgs boson properties, precision Standard Model measurements, as well as searches for new physics. Most of the results exploit the data collected in the last LHC run, providing pp collisions at a centre of mass energy of 13 TeV.

scholarly journals THE STUDY OF THE PROPERTIES OF THE EXTENDED HIGGS BOSON SECTOR WITHIN hMSSM MODEL

2019 ◽  
pp. 3-10
Author(s):  
T.V. Obikhod ◽  
E.A. Petrenko
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Cross Sections ◽  
Branching Fractions ◽  
New Physics ◽  
Boson Mass ◽  
Atlas Collaboration ◽  
Beyond The Standard Model ◽  
Higgs Boson Mass ◽  
The Standard Model

Using the latest experimental data, performed by ATLAS Collaboration and within the framework of the Minimal Supersymmetric Standard Model, we presented the calculations for cross sections times branching fractions, σ×Br, as a functions of the CP-even, H, Higgs boson mass, CP-odd, A, Higgs boson mass and charged, H±, Higgs boson mass. Using the restricted parameter set, received from the hMSSM+HDECAY and ”low-tb-high” scenarios, with the help of the computer programs SOFTSUSY, Prospino and SusHi, we received the large values of σ ×Br for A and H bosons at tanβ=2 for the planned 14 TeV at the LHC and found the large σ ×Br at tanβ=30 for charged Higgs boson. The obtained results are of experimental interest as they are connected with the experimental searches for new physics beyond the Standard Model at the LHC.

scholarly journals Indirect $$ \mathcal{CP} $$ probes of the Higgs-top-quark interaction: current LHC constraints and future opportunities

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Henning Bahl ◽  
Philip Bechtle ◽  
Sven Heinemeyer ◽  
Judith Katzy ◽  
Tobias Klingl ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Top Quark ◽  
Decay Channel ◽  
New Physics ◽  
Current Data ◽  
Quark Interaction ◽  
The Standard Model ◽  
Vector Bosons ◽  
Selection Of

Abstract The $$ \mathcal{CP} $$ CP structure of the Higgs boson in its coupling to the particles of the Standard Model is amongst the most important Higgs boson properties which have not yet been constrained with high precision. In this study, all relevant inclusive and differential Higgs boson measurements from the ATLAS and CMS experiments are used to constrain the $$ \mathcal{CP} $$ CP -nature of the top-Yukawa interaction. The model dependence of the constraints is studied by successively allowing for new physics contributions to the couplings of the Higgs boson to massive vector bosons, to photons, and to gluons. In the most general case, we find that the current data still permits a significant $$ \mathcal{CP} $$ CP -odd component in the top-Yukawa coupling. Furthermore, we explore the prospects to further constrain the $$ \mathcal{CP} $$ CP properties of this coupling with future LHC data by determining tH production rates independently from possible accompanying variations of the $$ t\overline{t}H $$ t t ¯ H rate. This is achieved via a careful selection of discriminating observables. At the HL-LHC, we find that evidence for tH production at the Standard Model rate can be achieved in the Higgs to diphoton decay channel alone.

scholarly journals NLO QCD corrections to off-shell $${t{\bar{t}}W^\pm }$$ production at the LHC: correlations and asymmetries

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Giuseppe Bevilacqua ◽  
Huan-Yu Bi ◽  
Heribertus Bayu Hartanto ◽  
Manfred Kraus ◽  
Jasmina Nasufi ◽  
...  
Keyword(s):  
Top Quark ◽  
Charge Asymmetry ◽  
New Physics ◽  
Atlas Collaboration ◽  
Narrow Width Approximation ◽  
Theoretical Predictions ◽  
Top Quark Decay ◽  
Quark Decay ◽  
Precision Observables ◽  
The Impact

AbstractRecent discrepancies between theoretical predictions and experimental data in multi-lepton plus b-jets analyses for the $$t{\bar{t}}W^\pm $$ t t ¯ W ± process, as reported by the ATLAS collaboration, have indicated that more accurate theoretical predictions and high precision observables are needed to constrain numerous new physics scenarios in this channel. To this end we employ NLO QCD computations with full off-shell top quark effects included to provide theoretical predictions for the $$\mathcal{R}= \sigma _{t{\bar{t}}W^+}/\sigma _{t{\bar{t}}W^-}$$ R = σ t t ¯ W + / σ t t ¯ W - cross section ratio at the LHC with $$\sqrt{s}=13$$ s = 13 TeV. Depending on the transverse momentum cut on the b-jet we obtain 2–3% theoretical precision on $$\mathcal{R}$$ R , which should help to shed some light on new physics effects that can reveal themselves only once sufficiently precise Standard Model theoretical predictions are available. Furthermore, triggered by these discrepancies we reexamine the charge asymmetry of the top quark and its decay products in the $$t{\bar{t}}W^\pm $$ t t ¯ W ± production process. In the case of charge asymmetries, that are uniquely sensitive to the chiral nature of possible new physics in this channel, theoretical uncertainties below 15% are obtained. Additionally, the impact of the top quark decay modelling is scrutinised by explicit comparison with predictions in the narrow-width approximation.

scholarly journals The Search for Feebly Interacting Particles

2021 ◽  
Vol 71 (1) ◽  
pp. 279-313
Author(s):  
Gaia Lanfranchi ◽  
Maxim Pospelov ◽  
Philip Schuster
Keyword(s):  
Dark Matter ◽  
Particle Physics ◽  
Interaction Strength ◽  
New Physics ◽  
Fine Tuning ◽  
Experimental Program ◽  
Interacting Particles ◽  
Fundamental Physics ◽  
The Standard Model ◽  
The Universe

At the dawn of a new decade, particle physics faces the challenge of explaining the mystery of dark matter, the origin of matter over antimatter in the Universe, the apparent fine-tuning of the electroweak scale, and many other aspects of fundamental physics. Perhaps the most striking frontier to emerge in the search for answers involves New Physics at mass scales comparable to that of familiar matter—below the GeV scale but with very feeble interaction strength. New theoretical ideas to address dark matter and other fundamental questions predict such feebly interacting particles (FIPs) at these scales, and existing data may even provide hints of this possibility. Emboldened by the lessons of the LHC, a vibrant experimental program to discover such physics is underway, guided by a systematic theoretical approach that is firmly grounded in the underlying principles of the Standard Model. We give an overview of these efforts, their motivations, and the decadal goals that animate the community involved in the search for FIPs, and we focus in particular on accelerator-based experiments.

scholarly journals Future e+e−Colliders at the Energy Frontier

2019 ◽  
Vol 206 ◽  
pp. 08001
Author(s):  
Tadeusz Lesiak
Keyword(s):  
Higgs Boson ◽  
Particle Physics ◽  
New Physics ◽  
Stages Of Development ◽  
Physics Program ◽  
Electron Positron ◽  
Energy Frontier

A future giant electron-positron collider, operating at the energy frontier, is a natural proposal in order to push particle physics into new regime of precise measurements, in particular in the sectors of electroweak observables and Higgs boson parameters. The four projects of such accelerators: two linear (ILC and CLIC) and two circular (FCC and CEPC) are currently in various stages of development. In view of the update of European HEP strategy for particle physics and expectations of important decisions from Japan, China and USA, the next few years will be critical as far as the decisions about the construction of such colliders are concerned. The paper concisely reviews the relevant aspects and challenges of the proposed accelerators and detectors along with the presumed schedules of construction and operation. The motivation and very attractive physics program for new e+e− colliders, spanning in particular perspectives in Higgs, electroweak, and neutrino sectors, together with expectations of searches for New Physics, will be discussed as well.

scholarly journals tt̄H Coupling Measurement with the ATLAS Detector at the LHC

2018 ◽  
Vol 182 ◽  
pp. 02052
Author(s):  
Asma Hadef
Keyword(s):  
Higgs Boson ◽  
Cross Sections ◽  
Top Quark ◽  
High Energy Physics ◽  
Center Of Mass ◽  
High Energy ◽  
New Physics ◽  
Decay Modes ◽  
Center Of Mass Energy ◽  
Higgs Decay

The Higgs boson was discovered on the 4th of July 2012 with a mass around 125 GeV by ATLAS and CMS experiments at LHC. Determining the Higgs properties (production and decay modes, couplings,...) is an important part of the high-energy physics programme in this decade. A search for the Higgs boson production in association with a top quark pair (tt̄H) at ATLAS [1] is summarized in this paper at an unexplored center-of-mass energy of 13 TeV, which could allow a first direct measurement of the top quark Yukawa coupling and could reveal new physics. The tt̄H analysis in ATLAS is divided into 3 channels according to the Higgs decay modes: H → Hadrons, H → Leptons and H → Photons. The best-fit value of the ratio of observed and Standard Model cross sections of tt̄H production process, using 2015-2016 data and combining all tt̄H final states, is 1:8±0:7, corresponds to 2:8σ (1:8σ) observed (expected) significance.

Sign in / Sign up

Export Citation Format

Share Document