#### Alladi Ramakrishnan Hall

#### From Fermi Theory to the Standard Model and Beyond: The Unitarity viewpoint

#### Dipankar Das

##### IIT Indore

*In this presentation, my objective is to provide a bottom-up perspective to the Standard Model of Particle Physics without directly appealing to nonabelian gauge theories and spontaneous symmetry breaking. First, I will motivate the Fermi theory as a first step towards a QFT for weak interactions. Then I will introduce a simplified but useful notion of unitarity which, we will demand, needs to be respected by the scattering amplitudes at high energies. I will then demonstrate how, by systematically invoking unitarity, the Fermi theory 'naturally' evolves into the Standard Model. Finally, I will close with a couple of examples demonstrating how this notion of unitarity may reveal nontrivial insights about what may lie beyond the standard electroweak theory.*

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