scholarly journals The upgraded ATLAS and CMS detectors and their physics capabilities

2015 ◽  
Vol 373 (2032) ◽  
pp. 20140046 ◽  
Author(s):  
Pippa S. Wells
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Particle Physics ◽  
Higgs Bosons ◽  
Full Potential ◽  
Beyond The Standard Model ◽  
High Luminosity ◽  
Decay Modes ◽  
Boson Pair Production ◽  
The Standard Model

The update of the European Strategy for Particle Physics from 2013 states that Europe's top priority should be the exploitation of the full potential of the LHC, including the high-luminosity upgrade of the machine and detectors with a view to collecting 10 times more data than in the initial design. The plans for upgrading the ATLAS and CMS detectors so as to maintain their performance and meet the challenges of increasing luminosity are presented here. A cornerstone of the physics programme is to measure the properties of the 125 GeV Higgs boson with the highest possible precision, to test its consistency with the Standard Model. The high-luminosity data will allow precise measurements of the dominant production and decay modes, and offer the possibility of observing rare modes including Higgs boson pair production. Direct and indirect searches for additional Higgs bosons beyond the Standard Model will also continue.

scholarly journals Synthesis on Heavy Higgs from the Standard Model to 2HDM and Beyond

2020 ◽  
Vol 18 ◽  
pp. 110-142
Author(s):  
Abdeljalil Habjia
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Cross Sections ◽  
Particle Physics ◽  
Hadron Collider ◽  
Signal Strength ◽  
Beyond The Standard Model ◽  
Decay Channels ◽  
Higgs Decay ◽  
The Standard Model

In the context of particle physics, within the ATLAS and CMS experiments at large hadron collider (LHC), this work presents the discussion of the discovery of a particle compatible with the Higgs boson by the combination of several decay channels, with a mass of the order of 125.5 GeV. With increased statistics, that is the full set of data collected by the ATLAS and CMS experiments at LHC ( s1/2 = 7GeV and s1/2 = 8GeV ), the particle is also discovered individually in the channel h-->γγ with an observed significance of 5.2σ and 4.7σ, respectively. The analysis dedicated to the measurement of the mass mh and signal strength μ which is defined as the ratio of σ(pp --> h) X Br(h-->X) normalized to its Standard Model where X = WW*; ZZ*; γγ ; gg; ff. The combined results in h-->γγ channel gave the measurements: mh = 125:36 ± 0:37Gev, (μ = 1:17 ± 0:3) and the constraint on the width Γ(h) of the Higgs decay of 4.07 MeV at 95%CL. The spin study rejects the hypothesis of spin 2 at 99 %CL. The odd parity (spin parity 0- state) is excluded at more than 98%CL. Within the theoretical and experimental uncertainties accessible at the time of the analysis, all results: channels showing the excess with respect to the background-only hypothesis, measured mass and signal strength, couplings, quantum numbers (JPC), production modes, total and differential cross-sections, are compatible with the Standard Model Higgs boson at 95%CL. Although the Standard Model is one of the theories that have experienced the greatest number of successes to date, it is imperfect. The inability of this model to describe certain phenomena seems to suggest that it is only an approximation of a more general theory. Models beyond the Standard Model, such as 2HDM, MSSM or NMSSM, can compensate some of its limitations and postulate the existence of additional Higgs bosons.

scholarly journals HIGGS SEARCHES AT THE TEVATRON

2010 ◽  
Vol 25 (27n28) ◽  
pp. 5097-5104
Author(s):  
◽  
KAZUHIRO YAMAMOTO
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Cross Section ◽  
Mass Range ◽  
Higgs Bosons ◽  
Beyond The Standard Model ◽  
Standard Model Higgs Boson ◽  
Significant Excess ◽  
Proton Antiproton ◽  
The Standard Model

We present the latest results on searches for the standard and beyond-the-standard model Higgs bosons in proton-antiproton collisions at [Formula: see text] by the CDF and DØ experiments at the Fermilab Tevatron. No significant excess is observed above the expected background, and the cross section limits for the Higgs bosons are calculated. It is noticed that the standard model Higgs boson in the mass range 163 – 166 GeV/c2 is excluded at the 95% C.L.

scholarly journals Outstanding questions: physics beyond the Standard Model

2012 ◽  
Vol 370 (1961) ◽  
pp. 818-830 ◽  
Author(s):  
John Ellis
Keyword(s):  
Dark Matter ◽  
Higgs Boson ◽  
Large Hadron Collider ◽  
Standard Model ◽  
Particle Physics ◽  
Hadron Collider ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
The Difference ◽  
The Universe

The Standard Model of particle physics agrees very well with experiment, but many important questions remain unanswered, among them are the following. What is the origin of particle masses and are they due to a Higgs boson? How does one understand the number of species of matter particles and how do they mix? What is the origin of the difference between matter and antimatter, and is it related to the origin of the matter in the Universe? What is the nature of the astrophysical dark matter? How does one unify the fundamental interactions? How does one quantize gravity? In this article, I introduce these questions and discuss how they may be addressed by experiments at the Large Hadron Collider, with particular attention to the search for the Higgs boson and supersymmetry.

scholarly journals Extended Scalar Sectors

2020 ◽  
Vol 70 (1) ◽  
pp. 197-223
Author(s):  
Jan Steggemann
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Particle Physics ◽  
Higgs Bosons ◽  
Precision Measurements ◽  
Final States ◽  
The Standard Model ◽  
Supersymmetric Models ◽  
Charged Higgs Bosons ◽  
Generic Extensions

Extended scalar sectors appear in various extensions of the Standard Model of particle physics, such as supersymmetric models. They are also generic extensions of the Standard Model and can address a number of its shortcomings. Direct searches for additional Higgs bosons and measurements of the 125-GeV Higgs boson, both of which provide insights into the different possible sectors, are carried out at the LHC. This review gives an overview of searches for the additional Higgs bosons and their implications for different models. The discussed analyses comprise searches for neutral and charged Higgs bosons that decay in various final states. In addition, the review summarizes the constraints from precision measurements, including in particular the observed couplings of the 125-GeV Higgs boson. While several models naturally incorporate a Higgs boson with couplings that are similar to the ones in the Standard Model, the measurements of the 125-GeV Higgs boson provide constraints on all considered extensions.

Perspectives in Particle Physics after the Discovery of the Higgs Boson

2018 ◽  
Vol 26 (1) ◽  
pp. 100-109
Author(s):  
Guido Tonelli
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Particle Physics ◽  
High Energy ◽  
Beyond The Standard Model ◽  
Short Overview ◽  
The Standard Model ◽  
New Challenges

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.

scholarly journals Higher order and top mass effects in Higgs boson pair production beyond the Standard Model

2018 ◽  
Author(s):  
Gudrun Heinrich ◽  
Gerhard Buchalla ◽  
Matteo Capozi ◽  
Alejandro Celis ◽  
Ludovic Scyboz
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Pair Production ◽  
Higher Order ◽  
Beyond The Standard Model ◽  
Boson Pair ◽  
Boson Pair Production ◽  
Mass Effects ◽  
The Standard Model ◽  
Top Mass

scholarly journals Review of physics results from the Tevatron: Higgs boson physics

2015 ◽  
Vol 30 (06) ◽  
pp. 1541006 ◽  
Author(s):  
Thomas R. Junk ◽  
Aurelio Juste
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Vector Boson ◽  
Branching Ratio ◽  
Gluon Fusion ◽  
Mass Range ◽  
Higgs Bosons ◽  
Boson Mass ◽  
Decay Modes ◽  
The Standard Model

We review the techniques and results of the searches for the Higgs boson performed by the two Tevatron collaborations, CDF and DØ. The Higgs boson predicted by the Standard Model was sought in the mass range 90 GeV < mH < 200 GeV in all main production modes at the Tevatron: gluon–gluon fusion, WH and ZH associated production, vector boson fusion, and [Formula: see text] production, and in five main decay modes: [Formula: see text], H→τ+τ-, H→WW(*), H→ZZ(*) and H→γγ. An excess of events was seen in the [Formula: see text] searches consistent with a Standard Model Higgs boson with a mass in the range 115 GeV < mH < 135 GeV . Assuming a Higgs boson mass of mH = 125 GeV , studies of Higgs boson properties were performed, including measurements of the product of the cross section times the branching ratio in various production and decay modes, constraints on Higgs boson couplings to fermions and vector bosons, and tests of spin and parity. We also summarize the results of searches for supersymmetric Higgs bosons, and Higgs bosons in other extensions of the Standard Model.

scholarly journals Search for Heavy Higgs Bosons in Fermionic Decay Channels with CMS

2018 ◽  
Vol 46 ◽  
pp. 1860058
Author(s):  
Ye Chen
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Confidence Level ◽  
Higgs Bosons ◽  
Final States ◽  
Centre Of Mass ◽  
Decay Channels ◽  
Upper Limits ◽  
The Standard Model ◽  
Cms Detector

Latest results of searches for heavy Higgs bosons in fermionic final states are presented using the CMS detector at the LHC. Results are based on pp collision data collected at centre-of-mass energies of 8 and 13 TeV which have been interpreted according to different extensions of the Standard Model such as MSSM, 2HDM, and NMSSM. These searches look for evidence of other scalar or pseudoscalar bosons, in addition to the observed SM-like 125 GeV Higgs boson, and set 95% confidence level upper limits in fermionic final states and benchmark models explored. The talk reviews briefly the major results obtained by the CMS Collaboration during Run I, and presents the most recent searches performed during Run II.

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