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Quantum Grav."],"published-print":{"date-parts":[[2021,7,12]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    In this paper we extend the projective symmetry of the full metric\u2013affine Einstein\u2013Hilbert theory to a new symmetry transformation in the space of affine connections called the\n                    <jats:italic>amplified symmetry<\/jats:italic>\n                    . We prove that the Lagrangian of the standard model of particle physics is invariant under this new symmetry. We also show that the gravitational Lagrangian can be modified so that the amplified symmetry extends to the gravitational sector and hence to the whole action. The new theory so constructed is shown to be dynamically equivalent to Einstein\u2013Cartan\u2019s though genuinely metric\u2013affine.\n                  <\/jats:p>","DOI":"10.1088\/1361-6382\/abed61","type":"journal-article","created":{"date-parts":[[2021,3,10]],"date-time":"2021-03-10T17:30:25Z","timestamp":1615397425000},"page":"135001","update-policy":"https:\/\/doi.org\/10.1088\/crossmark-policy","source":"Crossref","is-referenced-by-count":5,"title":["Projective and amplified symmetries in metric\u2013affine theories"],"prefix":"10.1088","volume":"38","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1165-4689","authenticated-orcid":false,"given":"Alfonso","family":"Garc\u00eda-Parrado","sequence":"first","affiliation":[]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8293-3802","authenticated-orcid":false,"given":"Ettore","family":"Minguzzi","sequence":"additional","affiliation":[]}],"member":"266","published-online":{"date-parts":[[2021,6,1]]},"reference":[{"year":"2013","author":"Aldrovandi","key":"cqgabed61bib1","type":"book"},{"article-title":"Geometric inequivalence of metric and Palatini formulations of general relativity","year":"2019","author":"Bejarano","key":"cqgabed61bib2","type":"preprint"},{"key":"cqgabed61bib3","doi-asserted-by":"publisher","first-page":"280","DOI":"10.1016\/j.physletb.2017.03.001","type":"journal-article","article-title":"On the (non-)uniqueness of the Levi-Civita solution in the Einstein\u2013Hilbert\u2013Palatini formalism","volume":"768","author":"Bernal","year":"2017","journal-title":"Phys. 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