{"id":7823,"date":"2022-06-20T18:30:00","date_gmt":"2022-06-20T16:30:00","guid":{"rendered":"https:\/\/www.lapth.cnrs.fr\/event\/higgs-alignment-and-the-top-quark\/"},"modified":"2022-06-20T18:30:00","modified_gmt":"2022-06-20T16:30:00","slug":"higgs-alignment-and-the-top-quark","status":"publish","type":"tribe_events","link":"https:\/\/www.lapth.cnrs.fr\/en\/event\/higgs-alignment-and-the-top-quark\/","title":{"rendered":"Higgs alignment and the top quark"},"content":{"rendered":"<p><span>In 1976, S. Weinberg and his student, E. Gildener (GW), proposed<\/span><br \/>\n<span>multi-Higgs models of electroweak symmetry breaking which are clas-<\/span><br \/>\n<span>sically scale-invariant. If this scale invariance is spontaneously broken,<\/span><br \/>\n<span>the Higgs boson is the resulting massless dilaton and, of all the model\u2019s<\/span><br \/>\n<span>scalars, its couplings to gauge bosons and fermions are exactly as in<\/span><br \/>\n<span>the one-Higgs-doublet Standard Model of Weinberg\u2019s 1967 \u201cModel of<\/span><br \/>\n<span>Leptons\u201d.<\/span><span> <\/span><span>That is, this Higgs boson is<\/span><span> <\/span><span>aligned<\/span><span>.<\/span><span> <\/span><span>But, since the clas-<\/span><br \/>\n<span>sical Higgs potential has an infinitely long flat minimum, there is no<\/span><br \/>\n<span>fixed mass scale \u2014 i.e., no fixed VEV \u2014 at this level and no concrete<\/span><br \/>\n<span>meaning to this statement.<\/span><br \/>\n<span>This scale invariance is<\/span><span> <\/span><span>explicitly<\/span><span> <\/span><span>broken by the renormalization<\/span><br \/>\n<span>scale \u039b in the one-loop approximation of the Coleman-E. Weinberg<\/span><br \/>\n<span>effective potential, the Higgs boson boson gets mass, and its VEV<\/span><br \/>\n<span>v<\/span><span> <\/span><span>is fixed by its relation to \u039b.<\/span><span> <\/span><span>GW assigned its value to be<\/span><span> <\/span><span>v<\/span><span> <\/span><span>=<\/span><br \/>\n<span>2<\/span><span>\u2212<\/span><span>1<\/span><span>\/<\/span><span>4<\/span><span>G<\/span><span>\u2212<\/span><span>1<\/span><span>\/<\/span><span>2<\/span><br \/>\n<span>F<\/span><span> <\/span><span>= 246 GeV. Now Higgs alignment means something, but<\/span><br \/>\n<span>is it preserved in one-loop order, i.e., is it<\/span><span> <\/span><span>natural<\/span><span>? And what about<\/span><br \/>\n<span>higher orders?<\/span><br \/>\n<span>In this talk, I will summarize the above in a two-Higgs-doublet<\/span><br \/>\n<span>model of the GW mechanism, emphasizing the surprisingly low masses<\/span><br \/>\n<span>of the model\u2019s BSM Higgs and the role of the top quark in Higgs<\/span><br \/>\n<span>alignment, update the important experimental consequences of this<\/span><br \/>\n<span>alignment \u2014 stressing the futility of most ATLAS and CMS searches<\/span><br \/>\n<span>for BSM Higgses, and preview the extension of these results to two-<\/span><br \/>\n<span>loops.<\/span><br \/>\n<span>This work was started in 2019 with \u0301<\/span><span>Eric Pilon and extended in 2020<\/span><br \/>\n<span>with Estia Eichten. The two-loop extension is done with Eichten.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>In 1976, S. Weinberg and his student, E. Gildener (GW), proposed multi-Higgs models of electroweak symmetry breaking which are clas- sically scale-invariant. If this scale invariance is spontaneously broken, the [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"template":"","meta":{"_acf_changed":false,"_tribe_events_status":"","_tribe_events_status_reason":"","footnotes":""},"tags":[],"tribe_events_cat":[18],"class_list":["post-7823","tribe_events","type-tribe_events","status-publish","hentry","tribe_events_cat-weekly-seminars","cat_weekly-seminars"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.lapth.cnrs.fr\/en\/wp-json\/wp\/v2\/tribe_events\/7823","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.lapth.cnrs.fr\/en\/wp-json\/wp\/v2\/tribe_events"}],"about":[{"href":"https:\/\/www.lapth.cnrs.fr\/en\/wp-json\/wp\/v2\/types\/tribe_events"}],"author":[{"embeddable":true,"href":"https:\/\/www.lapth.cnrs.fr\/en\/wp-json\/wp\/v2\/users\/1"}],"version-history":[{"count":0,"href":"https:\/\/www.lapth.cnrs.fr\/en\/wp-json\/wp\/v2\/tribe_events\/7823\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.lapth.cnrs.fr\/en\/wp-json\/wp\/v2\/media?parent=7823"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.lapth.cnrs.fr\/en\/wp-json\/wp\/v2\/tags?post=7823"},{"taxonomy":"tribe_events_cat","embeddable":true,"href":"https:\/\/www.lapth.cnrs.fr\/en\/wp-json\/wp\/v2\/tribe_events_cat?post=7823"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}