Vector-like Quarks

Branco, G. C.; N., Rebelo, M.

doi:10.22323/1.405.0004

Cited by 4 publications

(1 citation statement)

References 35 publications

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“…Meanwhile, the Higgs data have excluded the possibility of additional SM-like chiral fermions. In contrast, the vector-like quarks (VLQs) [1] are consistent with existing Higgs data since they do not receive their masses from Yukawa couplings to a Higgs doublet. The VLQs are color-triplet spin-1/2 fermions, and the left-and right-handed components transform with the same properties under the SM electroweak symmetry group.…”

Section: Introductionsupporting

confidence: 64%

Search for the singlet vector-like top quark in the $T\to tZ$ channel with $Z\to ν\barν$ at hadron colliders

Lin¹,

Wang²,

Shang³

et al. 2023

Preprint

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Based on a simplified model including a singlet vector-like top quark T with charge |Q| = 2/3, we analyze the prospects of observing T via the single T production in the tZ channel with Z decaying to neutrinos at the hadron-hadron colliders. This simplified model only includes two free parameters, the coupling constant g * and the T quark mass m T . To investigate the observability of the single T production, we perform a detailed background analysis and detector simulation for the collision energies 14 TeV, 27 TeV, and 100 TeV. We scan the g * − m T parameter space and show the exclusion and discovery capabilities on the T quark with the highest integrated luminosity designed at these colliders. Moreover, the limits from the narrowwidth approximation and electroweak precision observables are considered.

show abstract

Section: Introductionsupporting

confidence: 64%

Search for the singlet vector-like top quark in the $T\to tZ$ channel with $Z\to ν\barν$ at hadron colliders

Lin¹,

Wang²,

Shang³

et al. 2023

Preprint

View full text Add to dashboard Cite

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Global fit of modified quark couplings to EW gauge bosons and vector-like quarks in light of the Cabibbo angle anomaly

Crivellin

Kirk

Kitahara

et al. 2023

J. High Energ. Phys.

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There are two tensions related to the Cabibbo angle of the CKM matrix. First, the determinations of Vus from Kμ2, Kℓ3, and τ decays disagree at the 3σ level. Second, using the average of these results in combination with β decays (including super-allowed β decays and neutron decay), a deficit in first-row CKM unitarity with a significance of again about 3σ is found. These discrepancies, known as the Cabibbo Angle anomaly, can in principle be solved by modifications of W boson couplings to quarks. However, due to SU(2)L invariance, Z couplings to quarks are also modified and flavour changing neutral currents can occur. In order to consistently assess the agreement of a new physics hypothesis with data, we perform a combined analysis for all dimension-six Standard Model Effective Field Theory operators that generate modified W couplings to first and second generation quarks. We then study models with vector-like quarks, which are prime candidates for a corresponding UV completion as they can affect W -quark couplings at tree level, and we perform a global fit including flavour observables (in particular loop effects in ∆F = 2 processes). We find that the best fit can be obtained for the SU(2)L doublet vector-like quark Q as it can generate right-handed W-u-d and W-u-s couplings as preferred by data.

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Search for the singlet vector-like top quark in the channel with at hadron colliders*

et al. 2023

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Based on a simplified model including a singlet vector-like top quark $T$ with charge |Q|=$2/3$, we analyze the prospects of observing $T$ via the single $T$ production in the $tZ$ channel with $Z$ decaying to neutrinos at the hadron-hadron colliders. This simplified model only includes two free parameters, the coupling constant $g^*$ and the $T$ quark mass $m_T$. In order to investigate the observability of the single $T$ production, we make a detailed background analysis and detector simulation for the collision energy 14~TeV, 27~TeV and 100~TeV. We scan the $g^*-m_T$ parameter space and show the exclusion and discovery capabilities on the $T$ quark with the highest integrated luminosity designed at these colliders. Besides, the limits from the narrow-width approximation and electroweak precision observables are also been considered.

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Vector-like Quarks

Cited by 4 publications

References 35 publications

Search for the singlet vector-like top quark in the $T\to tZ$ channel with $Z\to ν\barν$ at hadron colliders

Search for the singlet vector-like top quark in the $T\to tZ$ channel with $Z\to ν\barν$ at hadron colliders

Global fit of modified quark couplings to EW gauge bosons and vector-like quarks in light of the Cabibbo angle anomaly

Search for the singlet vector-like top quark in the channel with at hadron colliders*

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