Threshold effects in the decay of heavy<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>b</mml:mi><mml:mo>′</mml:mo></mml:msup></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>t</mml:mi><mml:mo>′</mml:mo></mml:msup></mml:math>quarks

Chào, Y.; Chen, Kai-Feng; Chen, Shing-Kuo; Hou, W.-S.; Huang, Bin‐Juine; Lei, Y. J.

doi:10.1103/physrevd.84.014029

Cited by 3 publications

(3 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While the Q → qV rates essentially depend on the Q − q quark couplings, the heavy quark mass splittings |m Q1 − m Q2 | drive the strength of the heavy-to-heavy transitions [11,15]. If the quarks Q 1 and Q 2 belong to the same weak multiplet with a large mass splitting, the Q 1 → Q 2 V decay could be very rapid and dominate the other decay modes if there is no |κ Q1Q2 | suppression.…”

Section: B Decaymentioning

confidence: 99%

Long-Lived Heavy Quarks: A Review

Buchkremer

Schmidt

2013

Advances in High Energy Physics

View full text Add to dashboard Cite

We review the theoretical and experimental situation for long-lived heavy quarks, or bound states thereof, arising in simple extensions of the Standard Model. If these particles propagate large distances before their decay, they give rise to specific signatures requiring dedicated analysis methods. In particular, vector-like quarks with negligible couplings to the three known families could have eluded the past experimental searches. While most analyses assume prompt decays at the production vertex, novel heavy quarks might lead to signatures involving displaced vertices, new hadronic bound states, or decays happening outside of the detector acceptance. We perform reinterpretations of existing searches for short-and long-lived particles, and give suggestions on how to extend their reach to long-lived heavy quarks.

show abstract

Section: B Decaymentioning

confidence: 99%

Long-Lived Heavy Quarks: A Review

Buchkremer

Schmidt

2013

Advances in High Energy Physics

View full text Add to dashboard Cite

show abstract

“…tW ! ðbWÞW decays are close to 100%, provided that the mass difference is small [19]. For instance, for a mass splitting of 25 GeV, and for V t 0 b 0 ¼ 0:005 (which would correspond to A ¼ 0:99975 in our model), less than 5% of the decays will be b…”

Section: Introductionmentioning

confidence: 99%

Combined search for the quarks of a sequential fourth generation

Chatrchyan¹,

Khachatryan²,

Sirunyan³

et al. 2012

Phys. Rev. D

View full text Add to dashboard Cite

Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 fb À1 recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third-and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about AE20 GeV. These results significantly reduce the allowed parameter space for a fourth generation of fermions.

show abstract

“…The second model [190][191][192][193] adds a complete fourth generation of quarks to the known 3 × 3 CKM matrix. This implies the existence of another unitary V 4×4 mixing matrix which does not allow FCNC decays with Z bosons at leading order, as they need to be considered for the above vector-like t quark model.…”

Section: Fcnc Processesmentioning

confidence: 99%

Direct Top Quark Decay Width Measurement in the tt Lepton+Jets Channel at 8 TeV with the ATLAS Experiment

Philipp¹

View full text Add to dashboard Cite

The top quark t plays an essential role in the field of elementary particle physics -in particular due to its exceptional properties comprising a large mass, which approximately equals the mass of a tungsten atom, and an enormously short lifetime. This thesis is devoted to the study of a fundamental property of the top quark -its decay width. Its value is predicted by the established Standard Model of particle physics and deviations may hint at yet unknown physics beyond this model. A direct measurement of the decay width of the top quark is presented. The analysis is based on tt events in the lepton+jets decay channel using data taken in proton-proton collisions at a centre-of-mass energy of s = 8 TeV. The dataset was recorded in 2012 with the ATLAS detector at the Large Hadron Collider at CERN and corresponds to an integrated luminosity of 20.2 fb −1 . The decay width of the top quark is extracted by utilising a template fit to one-dimensional distributions of kinematic quantities, performed simultaneously in the hadronic and the leptonic decay branch of tt events. Since the measurement is a direct measurement of the top quark decay width, it is less model-dependent in comparison to indirect approaches. This enables the measurement to probe a broad class of Standard Model extensions.

show abstract

Threshold effects in the decay of heavyb′andt′quarks

Cited by 3 publications

References 21 publications

Long-Lived Heavy Quarks: A Review

Long-Lived Heavy Quarks: A Review

Combined search for the quarks of a sequential fourth generation

Direct Top Quark Decay Width Measurement in the tt Lepton+Jets Channel at 8 TeV with the ATLAS Experiment

Contact Info

Product

Resources

About