scholarly journals Sir Thomas Walter Bannerman Kibble. 23 December 1932—2 June 2016

Author(s):  
M. J. Duff ◽  
K. S. Stelle

Professor Tom Kibble was an internationally-renowned theoretical physicist whose contributions to theoretical physics range from the theory of elementary particles to modern early-Universe cosmology. The unifying theme behind all his work is the theory of non-abelian gauge theories, the Yang–Mills extension of electromagnetism. One of Kibble's most important pieces of work in this area was his study of the symmetry-breaking mechanism whereby the force-carrying vector particles in the theory can acquire a mass accompanied by the appearance of a massive scalar boson. This idea, put forward independently by Brout and Englert, by Higgs, and by Guralnik, Hagen and Kibble in 1964, and generalized by Kibble in 1967, lies at the heart of the Standard Model and all modern unified theories of fundamental particles. It was vindicated in 2012 by the discovery of the Higgs boson at CERN. According to Nobel Laureate Steven Weinberg: ‘Tom Kibble showed us why light is massless’; this is the fundamental basis of electromagnetism.

2016 ◽  
Vol 31 (25) ◽  
pp. 1630044 ◽  
Author(s):  
S. Ferrara ◽  
A. Kehagias ◽  
A. Sagnotti

Abdus Salam was a true master of 20th Century Theoretical Physics. Not only was he a pioneer of the Standard Model (for which he shared the Nobel Prize with S. Glashow and S. Weinberg), but he also (co)authored many other outstanding contributions to the field of Fundamental Interactions and their unification. In particular, he was a major contributor to the development of supersymmetric theories, where he also coined the word “Supersymmetry” (replacing the earlier “Supergauges” drawn from String Theory). He also introduced the basic concept of “Superspace” and the notion of “Goldstone Fermion” (Goldstino). These concepts proved instrumental for the exploration of the ultraviolet properties and for the study of spontaneously broken phases of super Yang–Mills theories and Supergravity. They continue to play a key role in current developments in Early-Universe Cosmology. In this contribution we review models of inflation based on Supergravity with spontaneously broken local supersymmetry, with emphasis on the role of nilpotent superfields to describe a de Sitter phase of our Universe.


2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Sheldon Lee Glashow

In this magisterial essay, Sheldon Lee Glashow examines the Yang–Mills model and its implications. This is history from the inside out, as a great master of theoretical physics reviews the development of the first and greatest non-abelian gauge theory and its role in the construction of the Standard Model of particle physics.


2017 ◽  
Vol 32 (09) ◽  
pp. 1741015 ◽  
Author(s):  
Ahmed Ali

The charge given to me by the organisers of the memorial meeting for Prof. Abdus Salam’s 90th birthday is to recall my personal impressions of him and review an aspect of the standard model (SM) physics related to my work. Salam was, first and foremost, a brilliant theoretical physicist whose work is still very much en vogue, currently being tested precisely by the experiments at the Large Hadron Collider (LHC). Salam was, however, equally effective as a scientific advisor to many institutions, such as IAEA and CERN, but also to the government of Pakistan as the chief scientific strategist. He was also an untiring advocate of scientific research and higher education in developing countries, which took a concrete form in the International Centre for Theoretical Physics (ICTP) in Trieste. I discuss these aspects of his scientific life seen from my perspective in the first part. In the second part of my talk, which may appear as a disjoint piece to the first, I summarise some selected topics in rare B-decays — the current flavour physics frontier. Experiments carried out over several decades are largely in agreement with the SM, thanks also to dedicated theoretical effort in their interpretation. However, this field is undergoing an anomalous phase in a number of key measurements, in particular reported by LHCb, triggering a very lively debate and model building. These anomalies, which I review here, are too numerous to be ignored, but none is individually significant enough to announce a breakdown of the SM.


2019 ◽  
Vol 7 (1) ◽  
pp. 233-236
Author(s):  
Mu-ming Poo ◽  
Alexander Wu Chao

Abstract Chen-Ning Yang ( ) is the most distinguished Chinese theoretical physicist. In 1954, together with Robert Mills, he formulated the Yang–Mills Gauge Theory, which led to the development of the Standard Model, the leading framework for understanding particle physics. In 1956, Yang and Tsung-Dao Lee ( ) proposed the possibility of parity non-conservation in weak interaction, which won them the Nobel Prize in Physics in 1957. Besides these two major achievements, Yang made many other seminal contributions to particle physics, statistical physics and condensed matter physics. At the end of 2003, Yang returned to China from the US and established the Institute for Advanced Study at Tsinghua University in Beijing. NSR’s Executive Editor-in-Chief Mu-ming Poo ( ), a neurobiologist, and Alexander Wu Chao ( ), an accelerator physicist at Stanford University, talked with Professor Yang on a variety of topics, ranging from his retrospective view on Yang–Mills theory, on his contemporary physicists, on tastes in scientific research, and on the current and future developments of Chinese science. The following is an excerpt from this conversation that took place on 21 March 2019 at Tsinghua University, Beijing.


2020 ◽  
Vol 2 (3) ◽  
pp. 196-224
Author(s):  
Vladimir P. Vizgin

The article explores domestic contribution to the creation of The Standard Model (SM). SM is a quantum field gauge theory of electromagnetic, weak and strong interactions, which is the basis of the modern theory of elementary particles. The process of its development covers a twenty-year period – from 1954 (the concept of non-Abelian Yang-Mills gauge fields) to the early 1970s, when the construction of renormalizable quantum chromodynamics and electroweak theory was completed. The reasons for the difficult perception of the Yang-Mills gauge field concept in the USSR are analyzed, associated primarily with the problem of “zero-charge” in quantum electrodynamics, and then in field theories of strong and weak interactions. This result, obtained by the leaders of the outstanding Russian scientific schools of theoretical physics, L. D. Landau, I. Ya. Pomeranchuk and their students, led to the rejection of the majority of Soviet physicists from field theory and to their transition to the position of a non-field phenomenological program (based on the S-matrix theory) in the construction of the theory of elementary particles.


2021 ◽  
Author(s):  
Ayan Nayak

The objective of this abstract is to perform a systematic review of the critical relationship between quarks and quantum chromodynamics. The topic of this review abstract is the relationship between quarks and quantum chromodynamics. This relationship has been considered and still is considered one of the most groundbreaking connections in particle physics as it has allowed scientists to get a better view at “quarks”, an elementary particle with no substructure. Quantum Chromodynamics expresses and is the theory of strong interaction between quarks and gluons which are fundamental particles making up hadrons such as neutrons and protons. The theory plays a crucial part in the standard model of particle physics. The quantum field theory supporting quantum chromodynamics is a non-abelian gauge theory in which the lagrangian will not undergo change under local transformations. Quarks are one half of the base on which quantum chromodynamics is founded on. Quarks play a crucial role in the functioning of quantum chromodynamics as a whole and as such, affect other physical systems closely related to quantum chromodynamics such as strong interactions, weak interactions, and spin classification. Fully understanding the relation between Quarks and Quantum Chromodynamics will allow us to understand the true roles that quarks play in complex quantum systems.


Author(s):  
Laurent Baulieu ◽  
John Iliopoulos ◽  
Roland Sénéor

A geometrical derivation of Abelian and non- Abelian gauge theories. The Faddeev–Popov quantisation. BRST invariance and ghost fields. General discussion of BRST symmetry. Application to Yang–Mills theories and general relativity. A brief history of gauge theories.


2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Upalaparna Banerjee ◽  
Joydeep Chakrabortty ◽  
Suraj Prakash ◽  
Shakeel Ur Rahaman ◽  
Michael Spannowsky

Abstract It is not only conceivable but likely that the spectrum of physics beyond the Standard Model (SM) is non-degenerate. The lightest non-SM particle may reside close enough to the electroweak scale that it can be kinematically probed at high-energy experiments and on account of this, it must be included as an infrared (IR) degree of freedom (DOF) along with the SM ones. The rest of the non-SM particles are heavy enough to be directly experimentally inaccessible and can be integrated out. Now, to capture the effects of the complete theory, one must take into account the higher dimensional operators constituted of the SM DOFs and the minimal extension. This construction, BSMEFT, is in the same spirit as SMEFT but now with extra IR DOFs. Constructing a BSMEFT is in general the first step after establishing experimental evidence for a new particle. We have investigated three different scenarios where the SM is extended by additional (i) uncolored, (ii) colored particles, and (iii) abelian gauge symmetries. For each such scenario, we have included the most-anticipated and phenomenologically motivated models to demonstrate the concept of BSMEFT. In this paper, we have provided the full EFT Lagrangian for each such model up to mass dimension 6. We have also identified the CP, baryon (B), and lepton (L) number violating effective operators.


2020 ◽  
Vol 80 (10) ◽  
Author(s):  
Upalaparna Banerjee ◽  
Joydeep Chakrabortty ◽  
Suraj Prakash ◽  
Shakeel Ur Rahaman

AbstractThe dynamics of the subatomic fundamental particles, represented by quantum fields, and their interactions are determined uniquely by the assigned transformation properties, i.e., the quantum numbers associated with the underlying symmetry of the model under consideration. These fields constitute a finite number of group invariant operators which are assembled to build a polynomial, known as the Lagrangian of that particular model. The order of the polynomial is determined by the mass dimension. In this paper, we have introduced an automated $${\texttt {Mathematica}}^{\tiny \textregistered }$$ Mathematica ® package, GrIP, that computes the complete set of operators that form a basis at each such order for a model containing any number of fields transforming under connected compact groups. The spacetime symmetry is restricted to the Lorentz group. The first part of the paper is dedicated to formulating the algorithm of GrIP. In this context, the detailed and explicit construction of the characters of different representations corresponding to connected compact groups and respective Haar measures have been discussed in terms of the coordinates of their respective maximal torus. In the second part, we have documented the user manual of GrIP that captures the generic features of the main program and guides to prepare the input file. We have attached a sub-program CHaar to compute characters and Haar measures for $$SU(N), SO(2N), SO(2N+1), Sp(2N)$$ S U ( N ) , S O ( 2 N ) , S O ( 2 N + 1 ) , S p ( 2 N ) . This program works very efficiently to find out the higher mass (non-supersymmetric) and canonical (supersymmetric) dimensional operators relevant to the effective field theory (EFT). We have demonstrated the working principles with two examples: the standard model (SM) and the minimal supersymmetric standard model (MSSM). We have further highlighted important features of GrIP, e.g., identification of effective operators leading to specific rare processes linked with the violation of baryon and lepton numbers, using several beyond standard model (BSM) scenarios. We have also tabulated a complete set of dimension-6 operators for each such model. Some of the operators possess rich flavour structures which are discussed in detail. This work paves the way towards BSM-EFT.


2014 ◽  
Vol 92 (12) ◽  
pp. 1501-1527 ◽  
Author(s):  
Carlos Castro

A Clifford Cl(5, C) unified gauge field theory formulation of conformal gravity and U(4) × U(4) × U(4) Yang–Mills in 4D, is reviewed along with its implications for the Pati–Salam (PS) group SU(4) × SU(2)L × SU(2)R, and trinification grand unified theory models of three fermion generations based on the group SU(3)C × SU(3)L × SU(3)R. We proceed with a brief review of a unification program of 4D gravity and SU(3) × SU(2) × U(1) Yang–Mills emerging from 8D pure quaternionic gravity. A realization of E8 in terms of the Cl(16) = Cl(8) ⊗ Cl(8) generators follows, as a preamble to F. Smith’s E8 and Cl(16) = Cl(8) ⊗ Cl(8) unification model in 8D. The study of chiral fermions and instanton backgrounds in CP2 and CP3 related to the problem of obtaining three fermion generations is thoroughly studied. We continue with the evaluation of the coupling constants and particle masses based on the geometry of bounded complex homogeneous domains and geometric probability theory. An analysis of neutrino masses, Cabbibo–Kobayashi–Maskawa quark-mixing matrix parameters, and neutrino-mixing matrix parameters follows. We finalize with some concluding remarks about other proposals for the unification of gravity and the Standard Model, like string, M, and F theories and noncommutative and nonassociative geometry.


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