scholarly journals Search for single production of vector-like B quark decaying to bZ at future linear colliders

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
Lin Han ◽  
Jie-Fen Shen

AbstractNew vector-like quarks are predicted in many new physics scenarios beyond the Standard Model (SM). Based on a model-independent framework, we investigate the prospect of discovering the SU(2) singlet vector-like bottom quark (VLQ-B) in $$e^{+}e^{-}$$ e + e - collisions at 3 TeV Compact Linear Collider. We study the single VLQ-B production process $$e^{-}e^{+}\rightarrow B{\bar{b}}\rightarrow Zb{\bar{b}}$$ e - e + → B b ¯ → Z b b ¯ with two types of decay channel: $$Z\rightarrow \ell ^{+}\ell ^{-}$$ Z → ℓ + ℓ - , and $$Z\rightarrow \nu {\bar{\nu }}$$ Z → ν ν ¯ . By carrying out a full simulation for the signals and the relevant SM backgrounds, the $$2\sigma $$ 2 σ exclusion limit and $$5\sigma $$ 5 σ discovery prospects are, respectively, obtained on the B quark mass and the coupling strength $$g^{*}$$ g ∗ with the integrated luminosity of 5 $$\hbox {ab}^{-1}$$ ab - 1 . Our numerical results show that the possible signals of the singlet VLQ-B might be detected at the future high-energy $$e^{+}e^{-}$$ e + e - linear colliders.

2012 ◽  
Vol 27 (21) ◽  
pp. 1250119
Author(s):  
CHONG-XING YUE ◽  
JIE-NIAN DAI ◽  
JIAO ZHANG ◽  
JING GUO

The eγ collider is better suited to study single production of the gauge bosons. In this paper, we first consider the contributions of the three-site Higgsless (3SHL) model and the left–right twin Higgs (LRTH) model to the standard model (SM) processes eγ→eZ and eγ→νeW, and then study single production of the new neutral and charged gauge bosons predicted by these two models via eγ collision in the future high energy e+e- linear collider experiments. We find that the correction effects of 3SHL model on the processes eγ→eZ and eγ→νeW might be detected in the future, while this is not the case for the LRTH model. The process eγ→eZ' can give rise to different signatures in the 3SHL and LRTH models and thus can be used to distinguish these two kinds of new physics models at the high energy e+e- linear colliders.


2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Xi-Yan Tian ◽  
Liu-Feng Du ◽  
Yao-Bei Liu

AbstractThe vectorlike top partners are potential signature of some new physics beyond the Standard Model at the TeV scale. In this paper, we propose to search for the vectorlike T quark with charge 2/3 in the framework of a simplified model where the top partners only couples with the third generation of Standard Model quarks. We investigate the observability for electroweak production of a vectorlike T quark in association with a standard model bottom quark through the process $$pp \rightarrow T\bar{b}j$$ p p → T b ¯ j with the subsequent decay mode of $$T\rightarrow t(\rightarrow b W^+\rightarrow b \ell ^{+} \nu _{\ell })h( \rightarrow \gamma \gamma )$$ T → t ( → b W + → b ℓ + ν ℓ ) h ( → γ γ ) , at the proposed High Energy Large Hadron Collider (HE-LHC) and Future Circular Collider in hadron-hadron mode (FCC-hh) including the realistic detector effects. The 95% confidence level excluded regions and the $$5\sigma $$ 5 σ discovery reach in the parameter plane of $$\kappa _{T}-m_T$$ κ T - m T , are respectively obtained at the HE-LHC with the integrated luminosity of 15 ab$$^{-1}$$ - 1 and the FCC-hh with the integrated luminosity of 30 ab$$^{-1}$$ - 1 . We also analyze the projected sensitivity in terms of the production cross section times branching fraction at the HE-LHC and FCC-hh.


2020 ◽  
Vol 80 (9) ◽  
Author(s):  
Xue Gong ◽  
Chong-Xing Yue ◽  
Hai-Mei Yu ◽  
Dong Li

AbstractExistences of vector-like quarks (VLQs) are predicted in many new physics scenarios beyond the Standard Model (SM). We study the possibility of detecting the vector-like bottom quark (VLQ-B) being the SU(2) singlet with electric charge $$-1/3$$ - 1 / 3 at Large Hadron electron Collider (LHeC) in a model-independent framework. The decay properties and single production of VLQ-B at the LHeC are explored. Three types of signatures are investigated. By carrying out a fast simulation for the signals and the corresponding backgrounds, the signal significances are obtained. Our numerical results show that detecting of VLQ-B via the semileptonic channel is better than via the fully hadronic or leptonic channel.


2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Aoife Bharucha ◽  
Diogo Boito ◽  
Cédric Méaux

Abstract In this paper we consider the decay D+ → π+ℓ+ℓ−, addressing in particular the resonance contributions as well as the relatively large contributions from the weak annihilation diagrams. For the weak annihilation diagrams we include known results from QCD factorisation at low q2 and at high q2, adapting the existing calculation for B decays in the Operator Product Expansion. The hadronic resonance contributions are obtained through a dispersion relation, modelling the spectral functions as towers of Regge-like resonances in each channel, as suggested by Shifman, imposing the partonic behaviour in the deep Euclidean. The parameters of the model are extracted using e+e− → (hadrons) and τ → (hadrons) + ντ data as well as the branching ratios for the resonant decays D+ → π+R(R → ℓ+ℓ−), with R = ρ, ω, and ϕ. We perform a thorough error analysis, and present our results for the Standard Model differential branching ratio as a function of q2. Focusing then on the observables FH and AFB, we consider the sensitivity of this channel to effects of physics beyond the Standard Model, both in a model independent way and for the case of leptoquarks.


2001 ◽  
Vol 16 (supp01b) ◽  
pp. 888-890
Author(s):  
◽  
BRUCE KNUTESON

We present a quasi-model-independent search for physics beyond the standard model. We define final states to be studied, and construct a rule that identifies a set of variables appropriate for any particular final state. A new algorithm ("Sleuth") searches for regions of excess in the space of those variables and quantifies the significance of any detected excess. After demonstrating the sensititvity of the method, we apply it to the semi-inclusive channel eμX collected in ≈108 pb -1 of [Formula: see text] collisions at [Formula: see text] at the DØ experiment at the Fermilab Tevatron. We find no evidence of new high pT physics in this sample.


2005 ◽  
Vol 20 (22) ◽  
pp. 5164-5173 ◽  
Author(s):  
BEATE HEINEMANN

Recent searches for physics beyond the Standard Model at high energy colliders are presented. The main focus is on searches for supersymmetry, extra dimensions and new gauge bosons. In all search analyses the data are found to agree well with the Standard Model background expectation and no evidence for contributions from physics beyond the Standard Model is found. The data are thus used to place limits on new physics scenarios.


2001 ◽  
Vol 16 (supp01a) ◽  
pp. 92-103 ◽  
Author(s):  
R. L. Culbertson

The search for physics beyond the Standard Model includes Technicolor particles, Higgs Bosons, compositeness, many variations of Supersymmetry, large extra dimensions, model-independent searches for anomalies, and other topics. This article reports a subset of these ongoing searches at the high-energy colliders, Tevatron, HERA and LEP.


2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Tao Han ◽  
Wolfgang Kilian ◽  
Nils Kreher ◽  
Yang Ma ◽  
Jürgen Reuter ◽  
...  

Abstract We explore the sensitivity of directly testing the muon-Higgs coupling at a high-energy muon collider. This is strongly motivated if there exists new physics that is not aligned with the Standard Model Yukawa interactions which are responsible for the fermion mass generation. We illustrate a few such examples for physics beyond the Standard Model. With the accidentally small value of the muon Yukawa coupling and its subtle role in the high-energy production of multiple (vector and Higgs) bosons, we show that it is possible to measure the muon-Higgs coupling to an accuracy of ten percent for a 10 TeV muon collider and a few percent for a 30 TeV machine by utilizing the three boson production, potentially sensitive to a new physics scale about Λ ∼ 30 − 100 TeV.


2004 ◽  
Vol 19 (15) ◽  
pp. 2505-2544 ◽  
Author(s):  
ALAKABHA DATTA ◽  
DAVID LONDON

In this paper we examine T-violating triple-product correlations (TP's) in B→V1V2 decays. TP's are excellent probes of physics beyond the standard model (SM) for two reasons: (i) within the SM, most TP's are expected to be tiny, and (ii) unlike direct CP asymmetries, TP's are not suppressed by the small strong phases which are expected in B decays. TP's are obtained via the angular analysis of B→V1V2. In a general analysis based on factorization, we demonstrate that the most promising decays for measuring TP's in the SM involve excited final-state vector mesons, and we provide estimates of such TP's. We find that there are only a handful of decays in which large TP's are possible, and the size of these TP's depends strongly on the size of nonfactorizable effects. We show that TP's which vanish in the SM can be very large in models with new physics. The measurement of a nonzero TP asymmetry in a decay where none is expected would specifically point to new physics involving large couplings to the right-handed b-quark.


2008 ◽  
Vol 23 (24) ◽  
pp. 3849-3861 ◽  
Author(s):  
J.-F. GRIVAZ

Recent searches for physics beyond the Standard Model at high-energy colliders are reviewed, with emphasis on supersymmetry, additional space dimensions, extra gauge bosons, leptoquarks and model-independent searches. The results reported are based on data samples of up to 0.5 and 2.5 fb -1 collected at HERA and at the Tevatron, respectively.


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