In July 2012, the two experiments ATLAS and CMS, operating at the CERN proton-proton collider LHC, announced the discovery of a new particle consistent with the Higgs boson. This observation confirms a key prediction of the Standard Model of particle physics, that the Universe is pervaded by a field which conveys mass to the elementary constituents of matter. This paper reviews the experimental effort which led to such a result, and the challanges that had to be overcome during the conception and constuction of LHC and its experiments, the most powerful accelerator and the most complex detectors ever built. Finally, the nature and role of CERN and the meaning and impact of fundamental research are briefly discussed.
The Nobel Prize in Physics 2013 has been awarded to P.W. Higgs and F. Englert for the conception of a theoretical framework that contributes to the understanding of the origin of mass of subatomic particles. The mechanism (known as the Higgs mechanism) has been recently confirmed by the observation of the fundamental particle predicted (the so called Higgs boson) by the ATLAS and CMS experiments of the Large Hadron Collider at CERN, Geneva. Particle physicists all over the world, both theoreticians and experimentalists, have contributed to the result in the last thirty years, to say the least: in the present paper an account is given of this discovery, a milestone in the current understanding of the microcosm.
We extend the coverage of resonant di-Higgs searches in the bb¯ bb¯ final state to the process pp → H1→ H2H2→ bb¯ bb¯ , where both H1,2 are spin-0 states beyond the Standard Model. Such a process constitutes a joint discovery mode for the new states H1 and H2. We present the first sensitivity study of this channel, using public LHC data to validate our analysis. We also provide a first estimate of the sensitivity of the search for the HL-LHC and future facilities like the HE-LHC and FCC-hh. We analyze the discovery potential of this search for several non-minimal scalar sector scenarios: an extension of the SM with two extra singlet scalar fields, the two-Higgs-doublet model and a two-Higgs doublet model plus a singlet, which captures the scalar potential features of the NMSSM. We find that this channel represents a novel, very powerful probe for extended Higgs sectors, offering complementary sensitivity to existing analyses ; K.M. is supported in part by the F.R.S.-FNRS under the Excellence of Science EOS be.h project n. 30820817 and by the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 707983. J.M.N. was partially supported by the Programa Atracción de Talento de la Comunidad de Madrid under grant 2017-T1/TIC-5202, and by Ramón y Cajal Fellowship contract RYC-2017-22986. J.M.N also acknowledges support from the Spanish MINECO's "Centro de Excelencia Severo Ochoa" Programme under grant SEV-2016-0597, from the European Union's Horizon 2020 research and innovation programme under the Marie SklodowskaCurie grant agreements 690575 (RISE InvisiblesPlus) and 674896 (ITN ELUSIVES) and from the Spanish Proyectos de I+D de Generación de Conocimiento via grant PGC2018- 096646-A-I00. C.V. is supported by the SLAC Panofsky Fellowship. D.B. thanks the Galileo Galilei Institute for theoretical physics for hospitality while part of this work was carried out. J.M.N. thanks the Korean Institute for Advanced Study (KIAS) for hospitality during the last stages of this work
A model-independent search for a narrow resonance produced in proton-proton collisions at s=8 TeV and decaying to a pair of 125 GeV Higgs bosons that in turn each decays into a bottom quark-antiquark pair is performed by the CMS experiment at the LHC. The analyzed data correspond to an integrated luminosity of 17.9 fb-1. No evidence for a signal is observed. Upper limits at a 95% confidence level on the production cross section for such a resonance, in the mass range from 270 to 1100 GeV, are reported. Using these results, a radion with decay constant of 1 TeV and mass from 300 to 1100 GeV, and a Kaluza-Klein graviton with mass from 380 to 830 GeV are excluded at a 95% confidence level ; California Earthquake Authority Fonds pour la Formation à la Recherche dans l'Industrie et dans l'Agriculture European Regional Development Fund State Fund for Fundamental Research of Ukraine: Ukraine Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro CS Fund: Croatia Fuel Cell Technologies Program Joint Institute for Nuclear Research Ministry of Education - Singapore Pakistan Atomic Energy Commission: Pakistan Consejo Nacional de Ciencia y Tecnología National Science and Technology Development Agency: Thailand Ministry for Business Innovation and Employment Institute for Research in Fundamental Sciences Fundacja na rzecz Nauki Polskiej Foundation for Promotion of Material Science and Technology of Japan: Taipei Hispanics in Philanthropy Korea Research Council for Industrial Science and Technology California Department of Fish and Game Compagnia di San Paolo Secretaría de Estado de Investigación, Desarrollo e Innovación National Research Foundation Qatar National Research Fund Ministry of Science ICT and Future Planning Canadian Mathematical Society A.G. Leventis Foundation U.S. Department of Energy Academy of Finland Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Türkiye Atom Enerjisi Kurumu Ministerio de Educación y Cultura Research Promotion Foundation: Cyprus Alfred P. Sloan Foundation National Science Foundation Science and Technology Facilities Council Human Growth Foundation Austrian Science Fund Fundação de Amparo à Pesquisa do Estado de São Paulo Secretaría de Educación Pública Bundesministerium für Wissenschaft, Forschung und Wirtschaft Fonds De La Recherche Scientifique - FNRS National Academy of Sciences of Ukraine Bundesministerium für Bildung und Forschung National Natural Science Foundation of China Instituto Nazionale di Fisica Nucleare Hungarian Scientific Research Fund Department of Atomic Energy, Government of India Universidade de Macau Rochester Academy of Science Department of Science and Technology, Government of Rajasthan Conselho Nacional de Desenvolvimento Científico e Tecnológico ?????????? ???? ??????????????? ???????????? (????) Belgian Federal Science Policy Office Canadian Anesthesiologists' Society Agentschap voor Innovatie door Wetenschap en Technologie Departamento Administrativo de Ciencia, Tecnología e Innovación Alexander von Humboldt-Stiftung European Commission Ministerstvo Školství, Mláde?e a T?lov?chovy National Institutes of Health: Hungary CERN European Regional Development Fund Ministero dell'Istruzione, dell'Università e della Ricerca: 20108T4XTM Ministry of Education, Youth and Science Serbia NSC General Secretariat for Research and Technology European Research Council Fonds Wetenschappelijk Onderzoek Santa Fe Institute Ministry of Education and Science Louisiana Academy of Sciences ; We congratulate our colleagues in the CERN accelerator departments for the excellent performance of the LHC and thank the technical and administrative staffs at CERN and at other CMS institutes for their contributions to the success of the CMS effort. In addition, we gratefully acknowledge the computing centers and personnel of the Worldwide LHC Computing Grid for delivering so effectively the computing infrastructure essential to our analyses. Finally, we acknowledge the enduring support for the construction and operation of the LHC and the CMS detector provided by the following funding agencies: BMWFW and FWF (Austria); FNRS and FWO (Belgium); CNPq , CAPES , FAPERJ , and FAPESP (Brazil); MES (Bulgaria); CERN ; CAS , MoST , and NSFC (China); COLCIENCIAS (Colombia); MSES and CSF (Croatia); RPF (Cyprus); MoER , ERC IUT and ERDF (Estonia); Academy of Finland , MEC , and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF , DFG , and HGF (Germany); GSRT (Greece); OTKA and NIH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); MSIP and NRF (Republic of Korea); LAS (Lithuania); MOE and UM (Malaysia); CINVESTAV , CONACYT , SEP , and UASLP-FAI (Mexico); MBIE (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland); FCT (Portugal); JINR (Dubna); MON , RosAtom , RAS and RFBR (Russia); MESTD (Serbia); SEIDI and CPAN (Spain); Swiss Funding Agencies (Switzerland); MST (Taipei); ThEPCenter , IPST , STAR and NSTDA (Thailand); TUBITAK and TAEK (Turkey); NASU and SFFR (Ukraine); STFC (United Kingdom); DOE and NSF (USA). Individuals have received support from the Marie-Curie program and the European Research Council and EPLANET (European Union); the Leventis Foundation ; the Alfred P. Sloan Foundation ; the Alexander von Humboldt Foundation ; the Belgian Federal Science Policy Office; the Fonds pour la Formation à la Recherche dans l'Industrie et dans l'Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium); the Ministry of Education , Youth and Sports ( MEYS ) of the Czech Republic; the Council of Science and Industrial Research, India; the HOMING PLUS program of the Foundation for Polish Science , cofinanced from European Union, Regional Development Fund; the Compagnia di San Paolo (Torino); the Consorzio per la Fisica (Trieste); MIUR project 20108T4XTM (Italy); the Thalis and Aristeia programs cofinanced by EU-ESF and the Greek NSRF; and the National Priorities Research Program by Qatar National Research Fund .
Worldwide LHC Computing Grid ; BMWFW (Austria) ; FWF (Austria) ; FNRS (Belgium) ; FWO (Belgium) ; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) ; Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) ; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ; MES (Bulgaria) ; CERN ; CAS (China) ; MoST, (China) ; NSFC (China) ; COLCIENCIAS (Colombia) ; MSES (Croatia) ; CSF (Croatia) ; RPF (Cyprus) ; MoER (Estonia) ; ERC IUT (Estonia) ; ERDF (Estonia) ; Academy of Finland (Finland) ; MEC, (Finland) ; HIP (Finland) ; CEA (France) ; CNRS/IN2P3 (France) ; BMBF (Germany) ; DFG (Germany) ; HGF (Germany) ; GSRT (Greece) ; OTKA (Hungary) ; NIH (Hungary) ; DAE (India) ; DST (India) ; IPM (Iran) ; SFI (Ireland) ; INFN (Italy) ; MSIP (Republic of Korea) ; NRF (Republic of Korea) ; LAS (Lithuania) ; MOE (Malaysia) ; UM (Malaysia) ; CINVESTAV (Mexico) ; CONACYT (Mexico) ; SEP (Mexico) ; UASLP-FAI (Mexico) ; MBIE (New Zealand) ; PAEC (Pakistan) ; MSHE (Poland) ; NSC (Poland) ; FCT (Portugal) ; JINR (Dubna) ; MON (Russia) ; RosAtom (Russia) ; RAS (Russia) ; RFBR (Russia) ; MESTD (Serbia) ; SEIDI (Spain) ; CPAN (Spain) ; Swiss Funding Agencies (Switzerland) ; MST (Taipei) ; ThEPCenter (Thailand) ; IPST (Thailand) ; STAR (Thailand) ; NSTDA (Thailand) ; TUBITAK (Turkey) ; TAEK (Turkey) ; NASU (Ukraine) ; SFFR (Ukraine) ; STFC (United Kingdom) ; DOE (USA) ; NSF (USA) ; Marie-Curie program ; European Research Council ; EPLANET (European Union) ; Leventis Foundation ; Alfred P. Sloan Foundation ; Alexander von Humboldt Foundation ; Belgian Federal Science Policy Office ; Fonds pour la Formation a la Recherche dans l'Industrie et dans l'Agriculture (FRIA-Belgium) ; Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium) ; Ministry of Education, Youth and Sports (MEYS) of the Czech Republic ; Council of Science and Industrial Research, India ; HOMING PLUS program of the Foundation for Polish Science ; European Union ; Regional Development Fund ; Compagnia di San Paolo (Torino) ; Consorzio per la Fisica (Trieste) ; MIUR project (Italy) ; Thalis program ; Aristeia program ; EU-ESF ; Greek NSRF ; National Priorities Research Program, Qatar National Research Fund ; Science and Technology Facilities Council ; MIUR project (Italy): 20108T4XTM ; Science and Technology Facilities Council: ST/M005356/1 ; Science and Technology Facilities Council: ST/K003542/1 ; Science and Technology Facilities Council: CMS ; Science and Technology Facilities Council: ST/L005603/1 ; Science and Technology Facilities Council: ST/K003844/1 GRIDPP ; Science and Technology Facilities Council: ST/K003844/1 ; Science and Technology Facilities Council: ST/K001256/1 ; Science and Technology Facilities Council: ST/I005912/1 ; Science and Technology Facilities Council: ST/L00609X/1 GRIDPP ; Science and Technology Facilities Council: ST/I505580/1 ; Science and Technology Facilities Council: ST/K001604/1 ; Science and Technology Facilities Council: ST/J004901/1 ; Science and Technology Facilities Council: ST/M005356/1 GRIDPP ; Science and Technology Facilities Council: ST/I005912/1 GRIDPP ; Science and Technology Facilities Council: ST/K001639/1 ; Science and Technology Facilities Council: ST/N000250/1 ; Science and Technology Facilities Council: ST/J50094X/1 ; Science and Technology Facilities Council: ST/M004775/1 ; Science and Technology Facilities Council: ST/J005665/1 ; Science and Technology Facilities Council: ST/L00609X/1 ; Science and Technology Facilities Council: GRIDPP ; A model-independent search for a narrow resonance produced in proton-proton collisions at root s= 8TeV and decaying to a pair of 125GeV Higgs bosons that in turn each decays into a bottom quark-antiquark pair is performed by the CMS experiment at the LHC. The analyzed data correspond to an integrated luminosity of 17.9fb(-1). No evidence for a signal is observed. Upper limits at a 95% confidence level on the production cross section for such a resonance, in the mass range from 270 to 1100 GeV, are reported. Using these results, a radion with decay constant of 1 TeV and mass from 300 to 1100 GeV, and a Kaluza-Klein graviton with mass from 380 to 830 GeV are excluded at a 95% confidence level. (C) 2015 CERN for the benefit of the CMS Collaboration. Published by Elsevier B.V.
A model-independent search for a narrow resonance produced in proton-proton collisions at √s=8 TeV and decaying to a pair of 125 GeV Higgs bosons that in turn each decays into a bottom quark-antiquark pair is performed by the CMS experiment at the LHC. The analyzed data correspond to an integrated luminosity of 17.9 fb-1. No evidence for a signal is observed. Upper limits at a 95% confidence level on the production cross section for such a resonance, in the mass range from 270 to 1100 GeV, are reported. Using these results, a radion with decay constant of 1 TeV and mass from 300 to 1100 GeV, and a Kaluza-Klein graviton with mass from 380 to 830 GeV are excluded at a 95% confidence level ; We acknowledge the enduring support for the construction and operation of the LHC and the CMS detector provided by the following funding agencies: BMWFW and FWF (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES and CSF (Croatia); RPF (Cyprus); MoER, ERC IUT and ERDF (Estonia); Academy of Finland, MEC, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NIH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); MSIP and NRF (Republic of Korea); LAS (Lithuania); MOE and UM (Malaysia); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); MBIE (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland); FCT (Portugal); JINR (Dubna); MON, RosAtom, RAS and RFBR (Russia); MESTD (Serbia); SEIDI and CPAN (Spain); Swiss Funding Agencies (Switzerland); MST (Taipei); ThEPCenter, IPST, STAR and NSTDA (Thailand); TUBITAK and TAEK (Turkey); NASU and SFFR (Ukraine); STFC (United Kingdom); DOE and NSF (USA). Individuals have received support from the Marie-Curie program and the European Research Council and EPLANET (European Union); the Leventis Foundation; the Alfred P. Sloan Foundation; the Alexander von Humboldt Foundation; the Belgian Federal Science Policy Office; the Fonds pour la Formation à la Recherche dans l'Industrie et dans l'Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technologie (IWTBelgium); the Ministry of Education, Youth and Sports (MEYS) of the Czech Republic; the Council of Science and Industrial Research, India; the HOMING PLUS program of the Foundation for Polish Science, cofinanced from European Union, Regional Development Fund; the Compagnia di San Paolo (Torino); the Consorzio per la Fisica (Trieste); MIUR project 20108T4XTM (Italy); the Thalis and Aristeia programs cofinanced by EU-ESF and the Greek NSRF; and the National Priorities Research Program by Qatar National Research Fund
BMWFW (Austria) ; FWF (Austria) ; FNRS (Belgium) ; FWO (Belgium) ; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) ; Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) ; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ; MES (Bulgaria) ; CERN ; CAS (China) ; MOST (China) ; NSFC (China) ; COLCIENCIAS (Colombia) ; MSES (Croatia) ; CSF (Croatia) ; RPF (Cyprus) ; SENESCYT (Ecuador) ; MoER (Estonia) ; ERC IUT (Estonia) ; ERDF (Estonia) ; Academy of Finland (Finland) ; MEC (Finland) ; HIP (Finland) ; CEA (France) ; CNRS/IN2P3 (France) ; BMBF (Germany) ; DFG (Germany) ; HGF (Germany) ; GSRT (Greece) ; OTKA (Hungary) ; NIH (Hungary) ; DAE (India) ; DST (India) ; IPM (Iran) ; SFI (Ireland) ; INFN (Italy) ; MSIP (Republic of Korea) ; NRF (Republic of Korea) ; LAS (Lithuania) ; MOE (Malaysia) ; UM (Malaysia) ; BUAP (Mexico) ; CINVESTAV (Mexico) ; CONACYT (Mexico) ; LNS (Mexico) ; SEP (Mexico) ; UASLP-FAI (Mexico) ; MBIE (New Zealand) ; PAEC (Pakistan) ; MSHE (Poland) ; NSC (Poland) ; FCT (Portugal) ; JINR (Dubna) ; MON (Russia) ; ROSATOM (Russia) ; RAS (Russia) ; RFBR (Russia) ; RAEP (Russia) ; MESTD (Serbia) ; SEIDI (Spain) ; CPAN (Spain) ; PCTI (Spain) ; FEDER (Spain) ; Swiss Funding Agencies (Switzerland) ; MST (Taipei) ; ThEPCenter (Thailand) ; IPST (Thailand) ; STAR (Thailand) ; NSTDA (Thailand) ; TUBITAK (Turkey) ; TAEK (Turkey) ; NASU (Ukraine) ; SFFR (Ukraine) ; STFC (United Kingdom) ; DOE (USA) ; NSF (USA) ; Marie-Curie programme (European Union) ; European Research Council (European Union) ; Horizon 2020 Grant (European Union) ; Leventis Foundation ; A. P. Sloan Foundation ; Alexander von Humboldt Foundation ; Belgian Federal Science Policy Office ; Fonds pour la Formation a la Recherche dans l'Industrie et dans l'Agriculture (FRIA-Belgium) ; Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium) ; Ministry of Education, Youth and Sports (MEYS) of the Czech Republic ; Council of Science and Industrial Research, India ; HOMING PLUS programme of the Foundation for Polish Science ; European Union, Regional Development Fund ; Mobility Plus programme of the Ministry of Science and Higher Education ; National Science Center (Poland) ; National Priorities Research Program by Qatar National Research Fund ; Programa Severo Ochoa del Principado de Asturias ; Thalis programme - EU-ESF ; Aristeia programme - EU-ESF ; Greek NSRF ; Rachadapisek Sompot Fund for Postdoctoral Fellowship, Chulalongkorn University (Thailand) ; Chulalongkorn Academic into Its 2nd Century Project Advancement Project (Thailand) ; Welch Foundation ; Weston Havens Foundation (USA) ; Horizon 2020 Grant (European Union): 675440 ; National Science Center (Poland): Harmonia 2014/14/M/ST2/00428 ; National Science Center (Poland): Opus 2014/13/B/ST2/02543 ; National Science Center (Poland): 2014/15/B/ST2/03998 ; National Science Center (Poland): 2015/19/B/ST2/02861 ; National Science Center (Poland): Sonata-bis 2012/07/E/ST2/01406 ; Welch Foundation: C-1845 ; A search for a massive resonance decaying into a pair of standard model Higgs bosons, in a final state consisting of two b quark-antiquark pairs, is performed. A data sample of proton-proton collisions at a centre-of-mass energy of 13 TeV is used, collected by the CMS experiment at the CERN LHC in 2016, and corresponding to an integrated luminosity of 35.9 fb(-1). The Higgs bosons are highly Lorentz-boosted and are each reconstructed as a single large-area jet. The signal is characterized by a peak in the dijet invariant mass distribution, above a background from the standard model multijet production. The observations are consistent with the background expectations, and are interpreted as upper limits on the products of the s-channel production cross sections and branching fractions of narrow bulk gravitons and radions in warped extra-dimensional models. The limits range from 126 to 1.4 fb at 95% confidence level for resonances with masses between 750 and 3000 GeV, and are the most stringent to date, over the explored mass range. (C) 2018 The Author(s). Published by Elsevier B.V.
The pattern of deviations from Standard Model predictions and couplings is different for theories of new physics based on a non-linear realization of the SU(2)L × U(1)Y gauge symmetry breaking and those assuming a linear realization. We clarify this issue in a model-independent way via its effective Lagrangian formulation in the presence of a light Higgs particle, up to first order in the expansions: dimension-six operators for the linear expansion and four derivatives for the non-linear one. Complete sets of gauge and gauge-Higgs operators are considered, implementing the renormalization procedure and deriving the Feynman rules for the non-linear expansion. We establish the theoretical relation and the differences in physics impact between the two expansions. Promising discriminating signals include the decorrelation in the non-linear case of signals correlated in the linear one: some pure gauge versus gauge-Higgs couplings and also between couplings with the same number of Higgs legs. Furthermore, anomalous signals expected at first order in the non-linear realization may appear only at higher orders of the linear one, and vice versa. We analyze in detail the impact of both type of discriminating signals on LHC physics. ; We also acknowledge partial support of the European Union network FP7 ITN INVISIBLES (Marie Curie Actions, PITN-GA-2011-289442), of CiCYT through the project FPA2009-09017, of CAM through the project HEPHACOS P-ESP-00346, of the European Union FP7 ITN UNILHC (Marie Curie Actions, PITN-GA- 2009-237920), of MICINN through the grant BES-2010-037869, of the Spanish MINECO's "Centro de Excelencia Severo Ochoa" Programme under grant SEV-2012-0249, and of the Italian Ministero dell'Universit`a e della Ricerca Scientifica through the COFIN program (PRIN 2008) and the contract MRTN-CT-2006-035505. The work of I.B. is supported by an ESR contract of the European Union network FP7 ITN INVISIBLES mentioned above. The work of L.M. is supported by the Juan de la Cierva programme (JCI-2011-09244). The work of O.J.P.E. is supported in part by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and by Funda¸c˜ao de Amparo `a Pesquisa do Estado de S˜ao Paulo (FAPESP), M.C.G-G and T.C are supported by USA-NSF grant PHY-09-6739, M.C.G-G is also supported by CUR Generalitat de Catalunya grant 2009SGR502 and together with J.G-F by MICINN FPA2010-20807 and consolider-ingenio 2010 program CSD-2008-0037. J.G-F is further supported by ME FPU grant AP2009-2546. I.B., J.G-F., M.C.G-G., B.G., L.M, and S.R. acknowledge CERN TH department and J.G-F. also acknowledges ITP Heidelberg for hospitality during part of this work. ; Peer reviewed
We consider the three dimensional electrodynamics described by a complex scalar field coupled with the U(1) gauge field in the presence of a Maxwell term, a Chern-Simons term and the Higgs potential. The Chern-Simons term provides a velocity dependent gauge potential and the presence of the Maxwell term makes the U(1) gauge field dynamical. We study the Hamiltonian formulation of this Maxwell-Chern-Simons-Higgs theory under the appropriate gauge fixing conditions.
In this work we explore the sensitivity to the Higgs self-coupling λ in the production of two Higgs bosons via vector boson scattering at the LHC. Although these production channels, concretely W+W−→HH and ZZ→HH, have lower rates than gluon-gluon fusion, they benefit from being tree level processes, being independent of top physics and having very distinctive kinematics that allow us to obtain very clean experimental signatures. This makes them competitive channels concerning the sensitivity to the Higgs self-coupling. In order to give predictions for the sensitivity to this coupling, we first study the role of λ at the subprocess level, both in and beyond the Standard Model, to move afterwards to the LHC scenario. We characterize the pp→HHjj case first and then provide quantitative results for the values of λ that can be probed at the LHC in vector boson scattering processes after considering the Higgs boson decays. We focus mainly on pp→bb¯bb¯jj, since it has the largest signal rates, and also comment on the potential of other channels, such as pp→bb¯γγjj, as they lead to cleaner, although smaller, signals. Our whole study is performed for a center of mass energy of s=14TeV and for various future expected LHC luminosities ; This work is supported by the European Union through the ITN ELUSIVES H2020-MSCA-ITN-2015//674896 and the RISE INVISIBLESPLUS H2020-MSCA-RISE-2015//690575, by the CICYT through the projects FPA2016-78645-P, by the Spanish Consolider-Ingenio 2010 Programme CPAN (CSD2007-00042) and by the Spanish MINECO's "Centro de Excelencia Severo Ochoa" Programme under grant SEV-2016-0597. This work has also been partially supported by CONICET and ANPCyT projects no. PICT 2016-0164 and no. PICT-2017-2765 (E.A.)
Large mass splittings between new scalars in two-Higgs-doublet models (2HDM) open a key avenue to search for these new states via exotic heavy Higgs decays. We discuss in detail the different search channels for these new scalars at the LHC in the presence of a sizable mass splitting, i.e. a hierarchical 2HDM scenario, taking into account the theoretical and experimental constraints. We provide benchmark planes to exploit the complementarity among these searches, analyzing their potential to probe the hierarchical 2HDM parameter space during LHC Run 2. ; Munich Institute for Astro- and Particle Physics (MIAPP) of the DFG cluster of excellence "Origin and Structure of the Universe"; US Department of Energy [DE-FG02-04ER-41298]; Fermilab Graduate Student Research Program in Theoretical Physics; United States Department of Energy [DE-AC02-07CH11359]; European Union [PIEF-GA-2013-625809] ; Open Access Journal. ; This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.
In: Political science quarterly: a nonpartisan journal devoted to the study and analysis of government, politics and international affairs ; PSQ, Band 12, Heft 3, S. 521-525
Journal of High Energy Physics 2015.9 (2015): 210 reproduced by permission of Scuola Internazionale Superiore di Studi Avanzati (SISSA) ; The measured values of the Higgs and top quark masses imply that the Standard Model potential is very likely to be unstable at large Higgs values. This is particularly problematic during inflation, which sources large perturbations of the Higgs. The instability could be cured by a threshold effect induced by a scalar with a large vacuum expectation value and directly connected to the Standard Model through a Higgs portal coupling. However, we find that in a minimal model in which the scalar generates inflation, this mechanism does not stabilize the potential because the mass required for inflation is beyond the instability scale. This conclusion does not change if the Higgs has a direct weak coupling to the scalar curvature. On the other hand, if the potential is absolutely stable, successful inflation in agreement with current CMB data can occur along a valley of the potential with a Mexican hat profile. We revisit the stability conditions, independently of inflation, and clarify that the threshold effect cannot work if the Higgs portal coupling is too small. We also show that inflation in a false Higgs vacuum appearing radiatively for a tuned ratio of the Higgs and top masses leads to an amplitude of primordial gravitational waves that is far too high, ruling out this possibility ; GB thanks Perimeter Institute for hospitality at the very beginning of this work. Research at Perimeter Institute is supported in part by the Government of Canada through Industry Canada, and by the Province of Ontario through the Ministry of Research and Information (MRI). GB thanks as well the Departament de Física Fondamental at the Universitat de Barcelona and the CERN Theory Division for hospitality at different stages of this work. CT acknowledges support of the Spanish Government through grant FPA2011-24568 (MICINN), and thanks Rhorry Gauld and Anupam Mazumdar for useful conversations. GB thanks Brando Bellazzini, Alberto Casas, Mikael Chala, José Ramón Espinosa, Mathias Garny, Gian Giudice and Felix Kahlhoefer for valuable discussions and comments on a draft version of this work. We also thank Isabella Masina and Alessio Notari for useful exchanges