English
Related papers

Related papers: Vector-like Singlet Quarks: a Roadmap

200 papers

We study the phenomenology of charged Higgs bosons ($H^\pm$) and Vector-Like Quarks (VLQs), denoted as $T$, the latter possessing a charge identical to the top quark one, within the framework of the Two Higgs Doublet Model Type-II…

High Energy Physics - Phenomenology · Physics 2024-03-13 Rachid Benbrik , Mohammed Boukidi , Stefano Moretti

Several theories beyond the Standard Model (BSM) predict heavy neutral leptons, or long-lived particles with unique signatures which are difficult to reconstruct. Another area of interest are vector-like quarks which lie at the heart of…

High Energy Physics - Experiment · Physics 2024-05-15 Sergio Grancagnolo

Dark Matter (DM) is a known unknown. Apart, current experimental constraints on flavor-changing neutral current (FCNC) processes involving up-type quarks also provide scope to explore physics beyond the Standard Model (SM). In this article,…

High Energy Physics - Phenomenology · Physics 2026-03-31 Subhaditya Bhattacharya , Lipika Kolay , Dipankar Pradhan , Abhik Sarkar

We propose a viable minimal model with spontaneous CP violation in the framework of a Two Higgs Doublet Model. The model is based on a generalised Branco-Grimus-Lavoura model with a flavoured $\mathbb{Z}_2$ symmetry, under which two of the…

High Energy Physics - Phenomenology · Physics 2019-10-02 Miguel Nebot , Francisco J. Botella , Gustavo C. Branco

The Littlest Higgs model contains a new vector-like heavy quark in the up sector. There are two interesting features of its existence. One is that it extends the $3\times3$ CKM matrix in the Standard Model to a $4\times3$ matrix and the…

High Energy Physics - Phenomenology · Physics 2008-11-26 Jae Yong Lee

We consider the framework of flavoured leptoquarks, in models with scalar or vector leptoquarks, and look for constraints to the parameter space of these models. Using primarily direct searches at the Large Hadron Collider (LHC) and…

High Energy Physics - Phenomenology · Physics 2024-03-01 Ivo de Medeiros Varzielas , Amartya Sengupta

If the LHC should fail to observe direct signals for new physics, it may become necessary to look for new physics effects in rare events such as flavour-changing decays of the top quark, which, in the Standard Model, are predicted to be too…

High Energy Physics - Phenomenology · Physics 2016-08-09 Debjyoti Bardhan , Gautam Bhattacharyya , Diptimoy Ghosh , Monalisa Patra , Sreerup Raychaudhuri

This is a brief summary of the latest searches for virtual effects of new physics in the top sector. In the framework of the Standard Model Effective Field Theory (SMEFT), I show how to resolve the structure of effective couplings by…

High Energy Physics - Phenomenology · Physics 2021-02-10 Susanne Westhoff

Scalar singlets under the Standard Model gauge group appear naturally in many well-motivated New Physics scenarios, such as the composite Higgs models. Unlike the Higgs boson in the Standard Model, they can induce large flavour-changing…

High Energy Physics - Phenomenology · Physics 2025-01-14 Biao-Feng Hou , Xin-Qiang Li , Ya-Dong Yang , Xing-Bo Yuan , Ming-Wang Zhang

We study the flavor physics in two extensions of the quark sector of the Standard Model (SM): a four generation model and a model with a single vector--like down--type quark (VDQ). In our analysis we take into account the experimental…

High Energy Physics - Phenomenology · Physics 2009-11-07 Tomer Yanir

Flavour-Changing-Neutral-Currents (FCNC) play an important r\^ ole in testing the Standard Model (SM) while probing the possibility of having New Physics beyond the SM. In the SM, FCNC are forbidden at three level, but arise through…

High Energy Physics - Phenomenology · Physics 2013-08-22 G. C. Branco , M. N. Rebelo

We investigate the pair production of a vector-like quark triplet with hypercharge 5/3 decaying into top quark and a complex scalar triplet with hypercharge 1 at the LHC. This novel scenario, featuring particles with exotic charges - two…

High Energy Physics - Phenomenology · Physics 2024-07-12 Avik Banerjee , Venugopal Ellajosyula , Luca Panizzi

There are strong arguments favoring the Flavor Democracy hypothesis (or the Democratic Mass Matrix approach) within the Standard Model framework. However, the large mass of the top quark ($m_t >> m_b, m_\tau$) poses an obstacle to the…

High Energy Physics - Phenomenology · Physics 2026-03-06 Burak Dagli , Saleh Sultansoy , Ismail Toy

We review the modular flavor symmetric models of quarks and leptons focusing on our works. We present some flavor models of quarks and leptons by using finite modular groups and discuss the phenomenological implications. The modular flavor…

High Energy Physics - Phenomenology · Physics 2023-07-19 Tatsuo Kobayashi , Morimitsu Tanimoto

New light singlet scalars with flavor-specific couplings represent a phenomenologically distinctive and flavor-safe alternative to the well-studied possibility of Higgs-portal scalars. However, in contrast to the Higgs portal,…

High Energy Physics - Phenomenology · Physics 2022-01-12 Brian Batell , Ayres Freitas , Ahmed Ismail , David McKeen , Mudit Rai

We show that for a heavy vector-like quark model with a down type isosinglet, branching ratio for $c\rightarrow u\gamma$ decay is enhanced by more than $\mathcal{O}(10^2)$ as compared to that in the Standard model when QCD corrections to…

High Energy Physics - Phenomenology · Physics 2018-12-26 Aritra Biswas , Sanjoy Mandal , Nita Sinha

We extend the standard model with two extra Higgs doublets. Making use of a symmetry principle, we present flavour symmetries based on cycle groups $Z_N$ that oblige each Higgs doublet to contribute to the mass of only one generation, thus…

High Energy Physics - Phenomenology · Physics 2017-10-30 Nuno Rosa Agostinho , David Emmanuel-Costa , J. I. Silva-Marcos

The Littlest Higgs Model with T-parity (LHT) belongs to the simplest new physics scenarios with new sources of flavour and CP violation. We present a new analysis of quark observables in the LHT model in view of the oncoming flavour…

High Energy Physics - Phenomenology · Physics 2016-04-07 Monika Blanke , Andrzej J. Buras , Stefan Recksiegel

We give a status report on quark flavour physics in view of the latest data from the B factories and the LHC, and discuss the impact of the latest experimental results on new physics in the MFV framework. We also show some examples of the…

High Energy Physics - Phenomenology · Physics 2013-05-21 Tobias Hurth , Farvah Mahmoudi

Quarks whose left- and right-handed chiral components are both singlets with respect to the SU(2) weak-isospin gauge group, offer interesting physics possibilities beyond the Standard Model (SM) already studied in many contexts. We here…

High Energy Physics - Phenomenology · Physics 2016-09-01 V. Barger , M. S. Berger , R. J. N. Phillips