BEGIN:VCALENDAR VERSION:2.0 PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN BEGIN:VEVENT SUMMARY:Vector-Like Quarks and Other Physics Beyond the Standard Model DTSTART:20250129T150000Z DTEND:20250129T170000Z DTSTAMP:20260704T001824Z UID:0aa722dd-ebad-49e3-a51e-a1aaccec6875 SEQUENCE:2 CREATED:20250129T091124Z DESCRIPTION:The Standard Model (SM) was first proposed more than 50 years ago and it is still one of the most successful theories in science. There are\, however\, some phenomena that the SM cannot explain\, such as dark m atter or the matter anti-matter asymmetry. Thus\, it is the job of theoret ical particle physicists to propose models which complement the SM\, expla ining some phenomena that it cannot.One such class of models are models wi th vector-like quarks (VLQs). VLQs are fermions which\, like the SM quarks \, are triplets of SU(3) but whose left- and right-handed components trans form in the same way under SU(2). On the one hand\, they are motivated fro m the top-down approach since they appear in some Grand Unified models\, s uch as E_6\, and they also appear in some extra dimension models\, such as the Randall and Sundrum warped geometry models. On the other hand\, they are also motivated from the bottom-up\, since they can explain deviations from unitarity of the CKM matrix and they can give new sources of CP viola tion. They can appear in seven different types of gauge covariant multiple ts. Out of those\, the singlets with hypercharges 2/3 or -1/3 and the doub lets with hypercharge 1/6 are the representations which contain only field s with the same electric charge as the SM quarks\, making them the simples t VLQ extensions. We have studied these extensions.There is a bigger class of models beyond the SM (which include models with VLQs)\, which are the models which have the same electroweak gauge group as the SM\, i.e.\, SU(2 ) x U(1). For this class of models\, the New Physics (NP) effects can be p arametrized by a set of observables called oblique parameters. We have com puted the oblique parameters in different general NP frameworks\, namely i n extensions of the SM with extra fermions (which include extensions with VLQs) and in extensions of the SM with extra scalars. LAST-MODIFIED:20250129T091149Z LOCATION:Sala P9 - Piso 2 do Edifício de Matemática (IST - Campus Alamed a) URL:http://df.vps.tecnico.ulisboa.pt/pt/eventos/vector-like-quarks-and-oth er-physics-beyond-the-standard-model/ X-ALT-DESC;FMTTYPE=text/html:

The Standard Model (SM) was first proposed more than 50 years ago and it is still one of the most successful theories in science. There are\, however\, some phenomena that the SM cannot explain\, such as dark matter or the matter anti-matter asymmetry. Thus\, it is the job of theoretical particle physicists to pro pose models which complement the SM\, explaining some phenomena that it ca nnot.

One such class of models are models with vector-like quarks (VLQs). VLQs are fermions which\, like the SM quarks\, are triplets of SU(3) but whose left- and right-handed compone nts transform in the same way under SU(2). On the one hand\, they are moti vated from the top-down approach since they appear in some Grand Unified m odels\, such as E_6\, and they also appear in some extra dimension models\ , such as the Randall and Sundrum warped geometry models. On the other han d\, they are also motivated from the bottom-up\, since they can explain de viations from unitarity of the CKM matrix and they can give new sources of CP violation.

They can appear in seven different types of gauge covariant multiplets. Out of those\, the singlets with hypercharges 2/3 o r -1/3 and the doublets with hypercharge 1/6 are the representations which contain only fields with the same electric charge as the SM quarks\, maki ng them the simplest VLQ extensions. We have studied these extensions.

There is a bigger class of models beyo nd the SM (which include models with VLQs)\, which are the models which ha ve the same electroweak gauge group as the SM\, i.e.\, SU(2) x U(1). For t his class of models\, the New Physics (NP) effects can be parametrized by a set of observables called oblique parameters. We have computed the obliq ue parameters in different general NP frameworks\, namely in extensions of the SM with extra fermions (which include extensions with VLQs) and in ex tensions of the SM with extra scalars.

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