Theory: Historical perspective and what have we learned from the Higgs so far

<!--HTML--><p><strong><span><span><span>Abstract:</span></span></span></strong></p> <p><span><span><span>This lecture will start with a summary of the history of spontaneous symmetry breaking in superconductivity and its application to particle physics by Englert, Brout and Higgs. This will be followed by a brief review of phenomenological studies of the Higgs boson prior to the LHC start-up. After summarising what we have learnt from ATLAS and CMS about the Higgs boson, I will emphasise that all its interactions pose theoretical puzzles. In the final part of the lecture I will show how the Standard Model Effective Field Theory (SMEFT) can be used to probe possible new physics, and ask whether the recent measurement of the W mass by CDF is pointing towards higher-dimensional SMEFT interactions of the Higgs boson.</span></span></span></p> <p><strong><span><span><span>Short bio:</span></span></span></strong></p> <p><span><span><span>John Ellis currently holds the Clerk Maxwell Professorship of Theoretical Physics at King's College in London. After obtaining a PhD from Cambridge University and holding post-doctoral positions at SLAC and Caltech, from 1973 to 2011 he worked for CERN, where he was Theory Division Leader for six years. </span></span></span></p> <p><span><span><span>His research interests focus on the phenomenological aspects of elementary particle physics and its connections with astrophysics, cosmology and gravity. Much of his work relates directly to experiment: interpreting results of searches for new particles and exploring the physics that could be done with future accelerators. A proposal he made in 1976 led to the discovery of the gluon in 1979, and he was one of the first to study how the Higgs boson could be produced and discovered. He has authored over a thousand scientific papers, with over eighty thousand citations in total. He has been active recently in efforts to understand the Higgs particle discovered at CERN, comparing the properties of this particle with the predictions of the Standard Model, and using effective field theory to understand the implications of the discovery for extensions of the Standard Model such as supersymmetry and other possible new physics such as dark matter. He is also now studying possible future particle accelerators and experiments to measure gravitational waves.</span></span></span></p> <p><span><span><span>He was elected a Fellow of the Royal Society of London in 1985, was appointed a </span><span><span>Commander of the Order of the British Empire (CBE) in 2012 for his services to science and technology</span></span><span><span>,</span></span><span>&nbsp;was elected&nbsp;</span><span>in 2015 </span><span>a Foreign Fellow of the Indian National Science Academy and a Foreign Member of the Estonian Academy of Sciences, and has been awarded several honorary doctorates.</span></span></span></p> <p><span><span><span><span>Prof. Ellis is known for his relentless efforts to involve non-European nations and institutions in CERN scientific and technological activities.</span></span></span></span></p>