# From a boson to the standard model Higgs: a case study in confirmation and model dynamics

## Abstract

Our paper studies the anatomy of the discovery of the Higgs boson at the Large Hadron Collider and its influence on the broader model landscape of particle physics. We investigate the phases of this discovery, which led to a crucial reconfiguration of the model landscape of elementary particle physics and eventually to a confirmation of the standard model (SM). A keyword search of preprints covering the electroweak symmetry breaking (EWSB) sector of particle physics, along with an examination of physicists own understanding of the discovery as documented in semiannual conferences, has allowed us an empirical investigation of its model dynamics. From our analyses we draw two main philosophical lessons concerning the nature of scientific reasoning in a complex experimental and theoretical environment. For one, from a confirmation standpoint, some SM alternatives could be considered even more confirmed by the Higgs discovery than the SM. Nevertheless, the SM largely remains the commonly accepted account of EWSB. We present criteria for comparing degrees of confirmation and expose some limits of a purely logical approach to understanding the Higgs discovery as a victory for the SM. Second, we understand the persistence of SM alternatives in the face of disfavourable evidence by borrowing the Lakatosian concept of a research programme, where the core idea behind a group of models survives, while other aspects adapt to incoming data. In order to apply this framework to the model landscape of EWSB, we must introduce a new category of research programme, the model-group, and we test its viability using the example of composite Higgs models.

## Keywords

Model dynamics Particle physics Confirmation Lakatosian research programmes Higgs boson Empirical epistemology## Notes

### Acknowledgements

Our paper was written with the support of the German Research Foundation (DFG) and is part of the Research Unit “The Epistemology of the Large Hadron Collider” (FOR 2063). We are indebted to Radin Dardashti, Robert Harlander, and the rest of the research unit for their many helpful comments throughout the writing process. For detailed comments, we would also like to thank the participants of the “Reasoning in Physics” workshop organized by the Center for Advanced Studies at LMU München and our helpful anonymous reviewers.

## References

- Achinstein, P. (1993). How to defend a theory without testing it: Niels Bohr and the “logic of pursuit”.
*Midwest Studies in Philosophy*,*18*(1), 90–120.CrossRefGoogle Scholar - Agashe, K., Contino, R., & Pomarol, A. (2005). The minimal composite Higgs model.
*Nuclear Physics B*,*719*, 165–187. https://doi.org/10.1016/j.nuclphysb.2005.04.035. arXiv:hep-ph/0412089.CrossRefGoogle Scholar - Arkani-Hamed, N., Cohen, A. G., Katz, E., & Nelson, A. E. (2002). The littlest Higgs.
*Journal of High Energy Physics*, 034. https://doi.org/10.1088/1126-6708/2002/07/034. arXiv:hep-ph/0206021. - ATLAS Collaboration (2011). ATLAS experiment presents latest Higgs search status. http://atlas.cern/updates/press-statement/atlas-experiment-presents-latest-higgs-search-status. Accessed: 11 April 2016.
- ATLAS Collaboration. (2012a). Combined search for the standard model Higgs boson using up to 4.9 fb-1 of pp collision data at sqrt(s) = 7 TeV with the ATLAS detector at the LHC.
*Physics Letters B*,*710*(1), 49–66.Google Scholar - ATLAS Collaboration, (2012b). Observation of a new particle in the search for the standard model Higgs boson with the ATLAS detector at the LHC.
*Physics Letters B*,*716*, 1–29. arXiv:1207.7214 [hep-ex]. - Azatov, A., & Galloway, J. (2012). Light custodians and Higgs physics in composite models.
*Physical Review D*,*85*, 055013. https://doi.org/10.1103/PhysRevD.85.055013. arXiv:1110.5646v2 [hep-ph].CrossRefGoogle Scholar - Bechtle, P., et al. (2016). Killing the cMSSM softly.
*The European Physical Journal C*,*76*(2), 96.CrossRefGoogle Scholar - Bhattacharya, S., & Jain, S. (2016). A review of the discovery of SM-like Higgs boson in H\( \rightarrow \gamma \gamma \) decay channel with the CMS detector at the LHC.
*Pramana*,*87*(3), 35.CrossRefGoogle Scholar - Borrelli, A. (2012). The case of the composite Higgs: The model as a “Rosetta Stone in contemporary high-energy physics.
*Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics*,*43*, 195–214.CrossRefGoogle Scholar - Campbell, R., & Vinci, T. (1983). Novel confirmation.
*Philosophy of Science*,*34*(4), 315–341.Google Scholar - Camporesi, T. (2012). Workshop summary and perspectives. In
*Presented at the Higgs coupling 2012 workshop*, Tokyo, Japan, November 18–20, 2012.Google Scholar - Carracciolo, F., Parolini, A., & Serone, M. (2013). UV completions of composite Higgs models with partial compositeness.
*Journal of High Energy Physics*, 066. https://doi.org/10.1007/JHEP02(2013)066. arXiv:1211.7290 [hep-ph]. - Chala, M. (2013). \(h \rightarrow \gamma \gamma \) excess and dark matter from composite Higgs models.
*Journal of High Energy Physics*, 122. https://doi.org/10.1007/JHEP01(2013)122. arXiv:1210.6208 [hep-ph]. - CMS Collaboration (2011). CMS search for the standard model Higgs boson in LHC data from 2010 and 2011. http://cms.web.cern.ch/news/cms-search-standard-model-higgs-boson-lhc-data-2010-and-2011. Accessed: 11 April 2016.
- CMS Collaboration. (2012a). Combined results of searches for the standard model Higgs boson in pp collisions at sqrt(s) = 7 TeV.
*Physics Letters B*,*710*(1), 26–48.Google Scholar - CMS Collaboration. (2012b). Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC.
*Physics Letters B*,*716*, 30–61. arXiv:1207.7235 [hep-ex]. - Cranmer, K. (2015). Practical statistics for the LHC. In
*Proceedings, 2011 European School of High-Energy Physics (ESHEP 2011): Cheile Gradistei, Romania, September 7–20, 2011*(pp. 267–308). arXiv:1503.07622 [physics.data-an]. - Dawid, R. (2017). Bayesian perspectives on the discovery of the Higgs particle.
*Synthese*,*194*, 377–394.CrossRefGoogle Scholar - Denisov, D. (2013). Moriond QCD 2013 experimental summary. In
*Presented at the XLVIIIth Rencontres de Moriond for QCD and high energy interactions*, La Thuile, Italy, March 9–16, 2013. arXiv:1306.6908 [hep-ex]. - Dimopoulos, S., & Susskind, L. (1979). Mass without scalars.
*Nuclear Physics B*,*155*, 237–252.CrossRefGoogle Scholar - Dissertori, G. (2012). Moriond 2012, QCD and high energy interactions: Experimental summary. In
*Presented at the XLVIIth Rencontres de Moriond for QCD and high energy interactions*, La Thuile, Italy, March 10–17, 2012. arXiv:1205.2209 [hep-ex]. - Dittmaier, S., Mariotti, C., Passarino, G., & Tanaka, R. (2011). Handbook of LHC Higgs cross sections: 1. inclusive observables. arXiv:1101.0593v3 [hep-ph].
- Eichten, E., Lane, K., & Martin, A. (2012). A Higgs imposter in low-scale technicolor. arXiv:1210.5462 [hep-ph].
- Ellis, J. & You, T. (2012). Global analysis of the Higgs candidate with mass 125 GeV.
*Journal of High Energy Physics*, JHEP09(2012):123. https://doi.org/10.1007/JHEP09(2012)123. arXiv:1207.1693 [hep-ph]. - Englert, F., & Brout, R. (1964). Broken symmetry and the mass of gauge vector mesons.
*Physical Review Letters*,*13*(9), 321–323.CrossRefGoogle Scholar - Franklin, A. (1993). Discovery, pursuit, and justification.
*Perspectives on Science*,*1*(2), 252–284.Google Scholar - Franklin, A. (2013).
*Shifting standards: Experiments in particle physics in the twentieth century*. Pittsburgh, PA: University of Pittsburgh Press.CrossRefGoogle Scholar - Friederich, S., Harlander, R., & Karaca, K. (2014). Philosophical perspectives on ad hoc hypotheses and the Higgs mechanism.
*Synthese*,*191*(16), 3897–3917.CrossRefGoogle Scholar - Giudice, G. F. (2013). Naturalness after LHC8. In
*Presented at high energy physics conference of the European Physical Society [EPS HEP]*, Stockholm, Sweden, July 18–24, 2013. arXiv:1307.7879 [hep-ph]. - Giudice, G. F., Grojean, C., Pomarol, A., & Rattazzi, R. (2007). The strongly-interacting light Higgs.
*Journal of High Energy Physics*,*JHEP06*, 045.CrossRefGoogle Scholar - Goldman, T., & Vinciarelli, P. (1974). Composite Higg field and finite symmetry breaking in gauge theories.
*Physical Review D*,*10*, 3431–3434.CrossRefGoogle Scholar - Grojean, C. (2012). Theoretical implications of the Higgs discovery. In
*Presented at the Higgs Coupling 2012 workshop*, Tokyo, Japan, November 18–20, 2012.Google Scholar - Guralnik, G., Hagen, C. R., & Kibble, T. W. (1964). Global conservation laws and massless particles.
*Physical Review Letters*,*13*(20), 585–587.CrossRefGoogle Scholar - Haber, H. E., Hempfling, R., & Hoang, A. H. (1997). Approximating the radiatively corrected Higgs mass in the minimal supersymmetric model.
*Zeitschrift für Physik C Particles and Fields*,*75*(3), 539–554.CrossRefGoogle Scholar - Harnik, R., Howe, K., & Kearney, J. (2017). Tadpole-induced electroweak symmetry breaking and pNGB Higgs models.
*Journal of High Energy Physics*, 111. https://doi.org/10.1007/JHEP03(2017)111. arXiv:1603.03772 [hep-ph]. - Hartmann, S. (1995). Models as a tool for theory construction: Some strategies of preliminary physics. In Herfel, W. E., Krajewski, W., Niiniluoto, I., and Wójcicki, R., editors,
*Theories and Models in Scientific Processes*(pp. 49–67). Rodopi, Amsterdam. Poznan Studies in the Philosophy of Science and the Humanities 44.Google Scholar - Hempel, C . G. (1965).
*Studies in the Logic of Confirmation*(pp. 3–46). New York: Free Press.Google Scholar - Higgs, P. (1964a). Broken symmetries and the masses of gauge bosons.
*Physical Review Letters*,*13*(16), 508–509.CrossRefGoogle Scholar - Higgs, P. (1964b). Broken symmetries, massless particles and gauge fields.
*Physical Review Letters*,*12*(2), 132–133.CrossRefGoogle Scholar - Howson, C. (1991). The ’old evidence’ problem.
*The British Journal for the Philosophy of Science*,*42*(4), 547–555.CrossRefGoogle Scholar - Howson, C., & Urbach, P. (1991). Bayesian reasoning in science.
*Nature*,*350*(6317), 371–374.CrossRefGoogle Scholar - Iliopoulos, J. (2014). Theory summary talk. In
*Presented at the XLVIXth Rencontres de Moriond for Electroweak Interactions and Unified Theories*, La Thuile, Italy, March 15–22, 2014.Google Scholar - Jeffrey, R. C. (1992).
*Probability and the art of judgement*., Cambridge studies in probability, induction, and decision theory Cambridge: Cambridge University Press.CrossRefGoogle Scholar - Johansson, L.-G., & Matsubara, K. (2011). String theory and general methodology: A mutual evaluation.
*Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics*,*42*, 199–210.CrossRefGoogle Scholar - Kaplan, D. B. (1991). Flavor at SSC energies: A new mechanism for dynamically generated fermion masses.
*Nuclear Physics B*,*365*, 259–278.CrossRefGoogle Scholar - Kraml, S. (2013). Implications of the 125 GeV Higgs for Supersymmetry. In
*Helmholtz alliance linear collider forum: Proceedings of the workshops Hamburg, Munich, Hamburg 2010–2012, Germany*(pp. 366–375), Hamburg. DESY, DESY.Google Scholar - Lakatos, I. (1978). Falsification and the methodology of scientific research programmes. In G. Currie & J. Worrall (Eds.),
*The methodology of scientific research programmes: Philosophical papers*(Vol. 1). New York: Cambridge University Press.CrossRefGoogle Scholar - Laudan, L. (1978).
*Progress and its problems: Towards a theory of scientific growth*. Berkeley: University of California Press.Google Scholar - Laudan, L., & Leplin, J. (1991). Empirical equivalence and underdetermination.
*Journal of Philosophy*,*88*(9), 449–472.CrossRefGoogle Scholar - Mangano, M. L. (2012). Hadron collider physics symposium: The incomplete summary. In
*Presented at the 23rd Hadron collider physics symposium*, Kyoto, Japan, November 12–16, 2012.Google Scholar - Mangano, M. L. (2013). Moriond QCD 2013 experimental summary. In
*Presented at the XLVIIIth Rencontres de Moriond for QCD and high energy interactions*, La Thuile, Italy, March 9–16, 2013. arXiv:1306.6908 [hep-ex]. - Marzocca, D., Serone, M., & Shu, J. (2012). General composite Higgs models.
*Journal of High Energy Physics*, JHEP08(2012):013. https://doi.org/10.1007/JHEP08(2012)013. arXiv:1205.0770 [hep-ph]. - Mättig, P., & Stöltzner, M. (2019). Model choice and crucial tests: On the empirical epistemology of the Higgs discovery.
*Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics*,*65*, 73–96.CrossRefGoogle Scholar - Mayo, D. G. (1991). Novel evidence and severe tests.
*Philosophy of Science*,*58*(4), 523–552.CrossRefGoogle Scholar - Moretti, L. (2002). For a Bayesian account of indirect confirmation.
*Dialectica*,*56*(2), 153–173.CrossRefGoogle Scholar - Morgan, M., & Morrison, M. (1999).
*Models as mediators: Perspectives on natural and social science*. Cambridge: Cambridge University Press.CrossRefGoogle Scholar - Morrison, M. (2007). Where have all the theories gone.
*Philosophy of Science*,*74*, 195–228.CrossRefGoogle Scholar - O’Luanaigh, C. (2013). New results indicate that new particle is a Higgs boson. http://home.cern/about/updates/2013/03/new-results-indicate-new-particle-higgs-boson. Accessed: 15 April 2017.
- Panico, G., Redi, M., Tesi, A., & Wulzer, A. (2013). On the tuning and the mass of the composite Higgs.
*Journal of High Energy Physics*, 051. https://doi.org/10.1007/JHEP03(2013)051. arXiv:1210.7114 [hep-ph]. - Peskin, M. (2012). Theoretical summary lecture for Higgs hunting 2012. In
*Presented at the 3rd Higgs hunting workshop: Discussions on Tevatron and LHC results*, Orsay, France, July 18-20, 2012. arXiv:1208.5152v2 [hep-ph]. - Peskin, M. E. (1997). Beyond the standard model. In Ellis, N. & Neubert, M. (eds)
*High-energy physics. Proceedings*(pp. 49–142). European School, Carry-le-Rouet, France. arXiv:hep-ph/9705479. - Pomarol, A. (2012). Electroweak symmetry breaking - status/directions. In
*Presented at the 36th international conference on high energy physics*, Melbourne, Australia, July 4–11, 2012.Google Scholar - Popper, K. R. (1963).
*Conjectures and refutations*. London: Routledge and Kegan Paul.Google Scholar - Redi, M. & Tesi, A. (2012). Implications of a light Higgs in composite models.
*Journal of High Energy Physics*, JHEP10(2012):166. https://doi.org/10.1007/JHEP10(2012)166. arXiv:1205.0232 [hep-ph]. - Sanz, V. (2012). Signatures of non-standard electroweak symmetry breaking. In
*Presented at the XLVIIth Rencontres de Moriond for electroweak interactions and unified theories*, La Thuile, Italy, March 3–10 2012. arXiv:1207.1912 [hep-ph]. - Schurz, G. (2014). Bayesian pseudo-confirmation, use-novelty, and genuine confirmation.
*Studies in History and Philosophy of Science Part A*,*45*(1), 87–96.CrossRefGoogle Scholar - Sphicas, P. (2013). Experimental summary. In
*Presented at the XLVIIIth Rencontres de Moriond for electroweak interactions and unified theories*, La Thuile, Italy, March 2–9, 2013.Google Scholar - Susskind, L. (1979). Dynamics of spontaneous symmetry breaking in the Weinberg–Salam theory.
*Physical Review D*,*20*, 2619–2625.CrossRefGoogle Scholar - ’t Hooft, G. (1971). Renormalizable Lagrangians for massive Yang-Mills fields.
*Nuclear Physics, Section B*,*35*, 167–188.CrossRefGoogle Scholar - Wells, J. D. (2016). The theoretical physics ecosystem behind the discovery of the Higgs boson. arXiv:1609.04268v1 [physics.hist-ph].
- Zwirner, F. (2013). Theory summary. In
*Presented at the XLVIIIth Rencontres de Moriond for electroweak interactions and unified theories*, La Thuile, Italy, March 2–9, 2013. arXiv:1310.3292 [hep-ph].