The Standard Model and Experiment

2021 ◽  
pp. 442-478
Author(s):  
J. Iliopoulos ◽  
T.N. Tomaras
Keyword(s):  
Standard Model ◽  
Heavy Quark ◽  
The Other ◽  
Hadron Spectroscopy ◽  
The Standard Model ◽  
Vector Bosons ◽  
The Rich ◽  
Basic Experiments ◽  
Intermediate Vector ◽  
Theory And Experiment

We review some basic experiments which established the validity of the Standard Model. They include the discovery of charm as well as the other two heavy quark flavours, that of the intermediate vector bosons W± and Z and of the BEH scalar. We show the successes of the model in the domain of hadron spectroscopy, but also its shortcomings. The rich subject of CP-violation in the hadronic and the leptonic sectors is reviewed, as well as the questions of flavour violating transitions. We end with an overall comparison between theory and experiment and point out the few cases in which some tension persists.

scholarly journals The Standard Model of Electroweak Interactions

2020 ◽  
pp. 35-81
Author(s):  
Guido Altarelli ◽  
Stefano Forte
Keyword(s):  
Gauge Symmetry ◽  
Standard Model ◽  
Matter Content ◽  
Higgs Particle ◽  
Electroweak Interactions ◽  
The Standard Model ◽  
Vector Bosons ◽  
Intermediate Vector

AbstractIn this chapter, we summarize the structure of the standard EW theory and specify the couplings of the intermediate vector bosons W±, Z and of the Higgs particle with the fermions and among themselves, as dictated by the gauge symmetry plus the observed matter content and the requirement of renormalizability

scholarly journals An Analysis of a Minimal Vectorlike Extension of the Standard Model

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
V. Beylin ◽  
M. Bezuglov ◽  
V. Kuksa ◽  
N. Volchanskiy
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Symmetry Breaking ◽  
Global Symmetry ◽  
Fundamental Field ◽  
Goldstone Bosons ◽  
The Standard Model ◽  
Vector Bosons ◽  
The Stability ◽  
Intermediate Vector

We analyze an extension of the Standard Model with an additionalSU(2)hypercolor gauge group keeping the Higgs boson as a fundamental field. Vectorlike interactions of new hyperquarks with the intermediate vector bosons are explicitly constructed. We also consider pseudo-Nambu–Goldstone bosons caused by the symmetry breakingSU(4)→Sp(4). A specific global symmetry of the model with zero hypercharge of the hyperquark doublets ensures the stability of a neutral pseudoscalar field. Some possible manifestations of the lightest states at colliders are also examined.

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.

Comments on the Market Crash: Six Months After

1988 ◽  
Vol 2 (3) ◽  
pp. 45-50 ◽  
Author(s):  
Hayne Leland ◽  
Mark Rubinstein
Keyword(s):  
Standard Model ◽  
Real Life ◽  
The Other ◽  
Financial Equilibrium ◽  
The Standard Model ◽  
Trading Mechanisms

Six months after the market crash of October 1987, we are still sifting through the debris searching for its cause. Two theories of the crash sound plausible -- one based on a market panic and the other based on large trader transactions -- though there is other evidence that is difficult to reconcile. If we are to believe the market panic theory or the Brady Commission's theory that the crash was primarily caused by a few large traders, we must strongly reject the standard model. We need to build models of financial equilibrium which are more sensitive to real life trading mechanisms, which account more realistically for the formation of expectations, and which recognize that, at any one time, there is a limited pool of investors available with the ability to evaluate stocks and take appropriate action in the market.

scholarly journals Weak scale from Planck scale: Mass scale generation in a classically conformal two-scalar system

2020 ◽  
Vol 2020 (3) ◽  
Author(s):  
Junichi Haruna ◽  
Hikaru Kawai
Keyword(s):  
Scalar Field ◽  
Standard Model ◽  
Planck Scale ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
The Other ◽  
Expectation Value ◽  
Weak Scale ◽  
The Standard Model ◽  
The One

Abstract In the standard model, the weak scale is the only parameter with mass dimensions. This means that the standard model itself cannot explain the origin of the weak scale. On the other hand, from the results of recent accelerator experiments, except for some small corrections, the standard model has increased the possibility of being an effective theory up to the Planck scale. From these facts, it is naturally inferred that the weak scale is determined by some dynamics from the Planck scale. In order to answer this question, we rely on the multiple point criticality principle as a clue and consider the classically conformal $\mathbb{Z}_2\times \mathbb{Z}_2$ invariant two-scalar model as a minimal model in which the weak scale is generated dynamically from the Planck scale. This model contains only two real scalar fields and does not contain any fermions or gauge fields. In this model, due to a Coleman–Weinberg-like mechanism, the one-scalar field spontaneously breaks the $ \mathbb{Z}_2$ symmetry with a vacuum expectation value connected with the cutoff momentum. We investigate this using the one-loop effective potential, renormalization group and large-$N$ limit. We also investigate whether it is possible to reproduce the mass term and vacuum expectation value of the Higgs field by coupling this model with the standard model in the Higgs portal framework. In this case, the one-scalar field that does not break $\mathbb{Z}_2$ can be a candidate for dark matter and have a mass of about several TeV in appropriate parameters. On the other hand, the other scalar field breaks $\mathbb{Z}_2$ and has a mass of several tens of GeV. These results will be verifiable in near-future experiments.

clause whereby it was a condition of acceptance that goods would be charged at prices ruling at the date of delivery. The defendant buyers replied on 27 May 1969, giving an order with differences from the sellers’ quotation and with their own terms and conditions, which had no price variation clause. The order had a tear-off acknowledgment for signature and return which accepted the order ‘on the terms and conditions thereon’. On 5 June 1969, the sellers, after acknowledging receipt of the order on 4 June, returned the acknowledgment form duly completed with a covering letter stating that delivery was to be ‘in accordance with our revised quotation of 23 May for delivery in ... March/April 1970’. The machine was ready by about September 1970, but the buyers could not accept delivery until November 1970. The sellers invoked the price increase clause and claimed £2,892 for the increase due to the rise in costs between 27 May 1969 and 1 April 1970, when the machine should have been delivered. Thesiger J gave judgment for the sellers for £2,892 and interest. The buyers appealed. The Court of Appeal unanimously reversed the first instance decision, all three judges feeling that the conclusive act was the sellers’ return of the tear-off acknowledgment slip. However, the reasons given by the judges for arriving at their decision differed. Bridge LJ and Lawton LJ broadly applied the standard model of ‘offer – counter-offer – acceptance’ to this ‘battle of the forms’, although both of them were clearly aware of the difficulties that this would cause. Lord Denning’s approach, not untypically, ranged much more widely. Unlike the other two judges, who can be seen to adopt a broadly ‘last shot’ theory (that is, that the ‘battle’ is won by the person who submits their terms last), Lord Denning was prepared to countenance a number of other possibilities. The following passages serve to indicate these divergences in approach: Butler Machine Tool Co Ltd v Ex-Cell-O Corpn (England) Ltd [1979] 1 WLR 401, CA, p 402

1995 ◽  
pp. 118-124
Keyword(s):  
Standard Model ◽  
Machine Tool ◽  
Price Increase ◽  
The Other ◽  
Price Variation ◽  
Covering Letter ◽  
The Standard Model ◽  
Court Of Appeal

scholarly journals The force and gravity of events

2016 ◽  
Vol 31 (16) ◽  
pp. 1630015 ◽  
Author(s):  
Robert Delbourgo
Keyword(s):  
Standard Model ◽  
Cosmological Constant ◽  
Ricci Scalar ◽  
The Other ◽  
Gauge Fields ◽  
Generalized Metric ◽  
The Standard Model ◽  
Property Space

Local events are characterized by “where”, “when” and “what”. Just as (bosonic) spacetime forms the backdrop for location and time, (fermionic) property space can serve as the backdrop for the attributes of a system. With such a scenario I shall describe a scheme that is capable of unifying gravitation and the other forces of nature. The generalized metric contains the curvature of spacetime and property separately, with the gauge fields linking the bosonic and fermionic arenas. The super-Ricci scalar can then automatically yield the spacetime Lagrangian of gravitation and the Standard Model (plus a cosmological constant) upon integration over property coordinates.

LIMITS ON NON-NEWTONIAN GRAVITY AND HYPOTHETICAL FORCES FROM MEASUREMENTS OF THE CASIMIR FORCE

2005 ◽  
Vol 20 (11) ◽  
pp. 2222-2231 ◽  
Author(s):  
F. CHEN ◽  
U. MOHIDEEN ◽  
P. W. MILONNI
Keyword(s):  
Standard Model ◽  
Extra Dimensions ◽  
Casimir Force ◽  
Gravitational Force ◽  
The Other ◽  
Newtonian Gravity ◽  
The Standard Model ◽  
Fundamental Forces ◽  
Two Bodies ◽  
New Particles

Modern unification theories that seek to unify gravity with the other fundamental forces predict a host of new particles outside the standard model. Many also invoke extra dimensions. Both of these effects lead to deviations from Newtonian gravity. For sub micron distance between two bodies, the Casimir force far exceeds the gravitational force. Thus both understanding and using the Casimir force is very important for checking the relevance of these unification theories. In particular, measurements of the Casimir force has allowed one to set some of the strongest constraints for corresponding distance regions. This paper summarizes the techniques used to measure the Casimir force and some of the limits that follow from them.

scholarly journals ELECTROWEAK UNIFICATION OF QUARKS AND LEPTONS IN A GAUGE GROUP SUC(3) × SU(4) × UX(1)

2012 ◽  
Vol 27 (21) ◽  
pp. 1250117 ◽  
Author(s):  
FAYYAZUDDIN
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Gauge Group ◽  
Lower Limit ◽  
Z Boson ◽  
Early Stage ◽  
Mass Scale ◽  
The Standard Model ◽  
Vector Bosons ◽  
The Universe

A model for electroweak unification of quarks and leptons, in a gauge group SUC(3) × SU(4) × UX(1) is constructed. The model requires, three generations of quarks and leptons which are replicas (mirror) of the standard quarks and leptons. The gauge group SU(4) × UX(1) is broken in such a way so as to reproduce standard model and to generate heavy masses for the vector bosons [Formula: see text], the leptoquarks and mirror fermions. It is shown lower limit on mass scale of mirror fermions is [Formula: see text], E- being the lightest mirror fermion coupled to Z boson. As the universe expands, the heavy matter is decoupled at an early stage of expansion and may be a source of dark matter. Leptoquarks in the model connect the standard model and mirror fermions. Baryon genesis in our universe implies antibaryon genesis in mirror universe.

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