| $\bf{> 1130}$ |
95 |
1 |
|
CMS |
| $>1230$ |
95 |
2 |
|
CMS |
| $\bf{> 1350}$ |
95 |
3 |
|
ATLS |
| $> 1000$ |
95 |
4 |
|
ATLS |
| $> 950$ |
95 |
5 |
|
ATLS |
| $> 1010$ |
95 |
6, 7 |
|
ATLS |
| $> 1140$ |
95 |
5, 8 |
|
ATLS |
| $> 1220$ |
95 |
9, 10 |
|
ATLS |
| $> 1370$ |
95 |
9, 11 |
|
ATLS |
| $> 910$ |
95 |
12 |
|
CMS |
| $> 845$ |
95 |
13 |
|
CMS |
| $> 730$ |
95 |
14 |
|
CMS |
| $> 880$ |
95 |
15 |
|
CMS |
| $> 620$ |
95 |
16 |
|
ATLS |
| $> 730$ |
95 |
17 |
|
ATLS |
| $> 810$ |
95 |
18 |
|
ATLS |
| $> 755$ |
95 |
19 |
|
ATLS |
| $> 675$ |
95 |
20 |
|
CMS |
| $\bf{> 190}$ |
95 |
21 |
|
D0 |
| $\bf{> 190}$ |
95 |
22 |
|
CDF |
| • • • We do not use the following data for averages, fits, limits, etc. • • • |
| $\text{<350, 580 - 635, >700}$ |
95 |
23 |
|
ATLS |
| $> 690$ |
95 |
24 |
|
ATLS |
| $> 480$ |
95 |
25 |
|
ATLS |
| $> 400$ |
95 |
26 |
|
ATLS |
| $> 350$ |
95 |
27 |
|
ATLS |
| $> 450$ |
95 |
28 |
|
ATLS |
| $> 685$ |
95 |
29 |
|
CMS |
| $> 611$ |
95 |
30 |
|
CMS |
| $> 372$ |
95 |
31 |
|
CDF |
| $> 361$ |
95 |
32 |
|
CMS |
| $> 338$ |
95 |
33 |
|
CDF |
| $\text{>380 - 430}$ |
95 |
34 |
|
RVUE |
| $> 268$ |
95 |
35, 36 |
|
CDF |
| $>199$ |
95 |
37 |
|
CDF |
| $>148$ |
95 |
38 |
|
CDF |
| $>96$ |
95 |
39 |
|
D0 |
| $>128$ |
95 |
40 |
|
D0 |
| $>75$ |
95 |
41 |
|
RVUE |
| $>85$ |
95 |
42 |
|
CDF |
| $>72$ |
95 |
43 |
|
CDF |
| $>54$ |
95 |
44 |
|
UA2 |
| $>43$ |
95 |
45 |
|
UA1 |
| $>34$ |
95 |
46 |
|
UA1 |
|
1
SIRUNYAN 2019AQ based on 35.9 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 13 TeV. Pair production of vector-like ${{\mathit b}^{\,'}}$ is seached for with one ${{\mathit b}^{\,'}}$ decaying into ${{\mathit Z}}{{\mathit b}}$ and the other ${{\mathit b}^{\,'}}$ decaying into ${{\mathit W}}{{\mathit t}}$ , ${{\mathit Z}}{{\mathit b}}$ , ${{\mathit h}}{{\mathit b}}$ . Events with an opposite-sign lepton pair consistent with coming from ${{\mathit Z}}$ and jets are used. Mass limits are obtained for a variety of branching ratios of ${{\mathit b}^{\,'}}$.
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2
SIRUNYAN 2019BW based on 35.9 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 13 TeV. The limit is for the pair-produced vector-like ${{\mathit b}^{\,'}}$ using all-hadronic final state. The analysis is made for the ${{\mathit Z}}{{\mathit b}}$ , ${{\mathit W}}{{\mathit t}}$ , ${{\mathit h}}{{\mathit b}}$ modes and mass limits are obtained for a variety of branching ratios.
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3
AABOUD 2018AW based on 36.1 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 13 TeV. The limit is for the pair-produced vector-like ${{\mathit b}^{\,'}}$ using lepton-plus-jets final state. The search is also sensitive to the decays into ${{\mathit Z}}{{\mathit b}}$ and ${{\mathit H}}{{\mathit b}}$ final states.
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4
AABOUD 2018CE based on 36.1 fb${}^{-1}$ of proton-proton data taken at $\sqrt {s }$ = 13 TeV. Events including a same-sign lepton pair are used. The limit is for a singlet model, assuming the branching ratios of ${{\mathit b}^{\,'}}$ into ${{\mathit Z}}{{\mathit b}}$ , ${{\mathit W}}{{\mathit t}}$ and ${{\mathit H}}{{\mathit b}}$ as predicted by the model.
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5
AABOUD 2018CL, AABOUD 2018CP based on 36.1 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 13 TeV. The limit is for the pair-produced vector-like ${{\mathit b}^{\,'}}$ using all-hadronic final state. The analysis is particularly powerful for the ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit h}}{{\mathit b}}$ mode. Assuming the pure decay only in this mode sets a limit ${\mathit m}_{{{\mathit b}^{\,'}}}$ $>$ 1010 GeV.
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6
AABOUD 2018CP based on 36.1 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 13 TeV. Pair and single production of vector-like ${{\mathit b}^{\,'}}$ are seached for with at least one ${{\mathit b}^{\,'}}$ decaying into ${{\mathit Z}}{{\mathit b}}$ . In the case of B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit b}}$ ) = 1, the limit is ${\mathit m}_{{{\mathit b}^{\,'}}}$ $>$ 1220 GeV.
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7
The limit is for the singlet model, assuming that the branching ratios into ${{\mathit W}}{{\mathit t}}$ , ${{\mathit Z}}{{\mathit b}}$ , ${{\mathit h}}{{\mathit b}}$ add up to one.
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8
The limit is for the doublet model, assuming that the branching ratios into ${{\mathit W}}{{\mathit t}}$ , ${{\mathit Z}}{{\mathit b}}$ , ${{\mathit h}}{{\mathit b}}$ add up to one.
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9
AABOUD 2018CR based on 36.1 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 13 TeV. A combination of searches for the pair-produced vector-like ${{\mathit b}^{\,'}}$ in various decay channels ( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit W}}{{\mathit t}}$ , ${{\mathit Z}}{{\mathit b}}$ , ${{\mathit h}}{{\mathit b}}$ ). Also a model-independent limit is obtained as ${\mathit m}_{{{\mathit b}^{\,'}}}$ $>$ 1.03 TeV, assuming that the branching ratios into ${{\mathit Z}}{{\mathit b}}$ , ${{\mathit W}}{{\mathit t}}$ , and ${{\mathit h}}{{\mathit b}}$ add up to one.
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10
The limit is for the singlet ${{\mathit b}^{\,'}}$.
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11
The limit is for ${{\mathit b}^{\,'}}$ in a weak isospin doublet (${{\mathit t}^{\,'}},{{\mathit b}^{\,'}}$) and $\vert {{\mathit V}}_{{{\mathit t}^{\,'}}{{\mathit b}}}\vert $ ${}\ll$ $\vert {{\mathit V}}_{{{\mathit t}}{{\mathit b}^{\,'}}}\vert $. For a ${{\mathit b}^{\,'}}$ in a doublet with a charge $−$4/3 vector-like quark, the limit ${\mathit m}_{{{\mathit b}^{\,'}}}$ $>$ 1.14 TeV is obtained.
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12
SIRUNYAN 2018BM based on 35.9 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 13 TeV. The limit is for the pair-produced vector-like ${{\mathit b}^{\,'}}$. Three channels (single lepton, same-charge 2 leptons, or at least 3 leptons) are considered for various branching fraction combinations. Assuming B( ${{\mathit t}}{{\mathit W}}$ ) = 1, the limit is 1240 GeV and for B( ${{\mathit b}}{{\mathit Z}}$ ) = 1 it is 960 GeV.
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13
SIRUNYAN 2018Q based on 19.7 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 8 TeV. The limit is for the pair-produced vector-like ${{\mathit b}^{\,'}}$ that couple only to light quarks. Upper cross section limits on the single production of a ${{\mathit b}^{\,'}}$ and constraints for other decay channels ( ${{\mathit Z}}{{\mathit q}}$ and ${{\mathit H}}{{\mathit q}}$ ) are also given in the paper.
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14
SIRUNYAN 2017AU based on $2.3 - 2.6$ fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 13 TeV. Limit on pair-produced singlet vector-like ${{\mathit b}^{\,'}}$ using one lepton and several jets. The mass bound is given for a ${{\mathit b}^{\,'}}$ transforming as a singlet under the electroweak symmetry group, assumed to decay through ${{\mathit W}}$, ${{\mathit Z}}$ or Higgs boson (which decays to jets) and to a third generation quark.
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15
KHACHATRYAN 2016AN based on 19.7 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 8 TeV. Limit on pair-produced vector-like ${{\mathit b}^{\,'}}$ using 1, 2, and $>$2 leptons as well as fully hadronic final states. Other limits depending on the branching fractions to ${{\mathit t}}{{\mathit W}}$ , ${{\mathit b}}{{\mathit Z}}$ , and ${{\mathit b}}{{\mathit H}}$ are given in Table IX.
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16
AAD 2015BY based on 20.3 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 8 TeV. Limit on pair-produced vector-like ${{\mathit b}^{\,'}}$ assuming the branching fractions to ${{\mathit W}}$, ${{\mathit Z}}$, and ${{\mathit h}}$ modes of the singlet model. Used events containing ${}\geq{}2{{\mathit \ell}}$ + $\not E_T$ + ${}\geq{}$2j (${}\geq{}$1 ${{\mathit b}}$) and including a same-sign lepton pair.
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17
AAD 2015BY based on 20.3 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 8 TeV. Limit on pair-produced chiral ${{\mathit b}^{\,'}}$-quark. Used events containing ${}\geq{}2{{\mathit \ell}}$ + $\not E_T$ + ${}\geq{}$2j (${}\geq{}$1 ${{\mathit b}}$) and including a same-sign lepton pair.
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18
AAD 2015Z based on 20.3 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 8 TeV. Used events with ${{\mathit \ell}}$ + $\not E_T$ + ${}\geq{}$6j (${}\geq{}$1 ${{\mathit b}}$) and at least one pair of jets from weak boson decay, primarily designed to select the signature ${{\mathit b}^{\,'}}$ ${{\overline{\mathit b}}^{\,'}}$ $\rightarrow$ ${{\mathit W}}{{\mathit W}}{{\mathit t}}{{\overline{\mathit t}}}$ $\rightarrow$ ${{\mathit W}}{{\mathit W}}{{\mathit W}}{{\mathit W}}{{\mathit b}}{{\overline{\mathit b}}}$ . This is a limit on pair-produced vector-like ${{\mathit b}^{\,'}}$. The lower mass limit is 640 GeV for a vector-like singlet ${{\mathit b}^{\,'}}$.
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19
Based on 20.3 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 8 TeV. No significant excess over SM expectation is found in the search for pair production or single production of ${{\mathit b}^{\,'}}$ in the events with dilepton from a high $p_T$ ${{\mathit Z}}$ and additional jets (${}\geq{}$ 1 ${{\mathit b}}$-tag). If instead of B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit W}}{{\mathit t}}$ ) = 1 an electroweak singlet with B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit W}}{{\mathit t}}$ ) $\sim{}$ 0.45 is assumed, the limit reduces to 685 GeV.
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20
Based on 5.0 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 7 TeV. CHATRCHYAN 2013I looked for events with one isolated electron or muon, large $\not E_T$, and at least four jets with large transverse momenta, where one jet is likely to originate from the decay of a bottom quark.
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21
Result is based on 1.1 fb${}^{-1}$ of data. No signal is found for the search of long-lived particles which decay into final states with two electrons or photons, and upper bound on the cross section times branching fraction is obtained for 2 $<$ c $<$ 7000 mm; see Fig. 3. 95$\%$ CL excluded region of ${{\mathit b}^{\,'}}$ lifetime and mass is shown in Fig. 4.
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22
ACOSTA 2003 looked for long-lived fourth generation quarks in the data sample of 90 pb${}^{-1}$ of $\sqrt {\mathit s }$=1.8 TeV ${{\mathit p}}{{\overline{\mathit p}}}$ collisions by using the muon-like penetration and anomalously high ionization energy loss signature. The corresponding lower mass bound for the charge (2/3)e quark (${{\mathit t}^{\,'}}$) is 220 GeV. The ${{\mathit t}^{\,'}}$ bound is higher than the ${{\mathit b}^{\,'}}$ bound because ${{\mathit t}^{\,'}}$ is more likely to produce charged hadrons than ${{\mathit b}^{\,'}}$. The 95$\%$ CL upper bounds for the production cross sections are given in their Fig.$~$3.
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23
AAD 2015AR based on 20.3 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 8 TeV. Used lepton-plus-jets final state. See Fig. 24 for mass limits in the plane of B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit W}}{{\mathit t}}$ ) vs. B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit H}}{{\mathit b}}$ ) from ${{\mathit b}^{\,'}}$ ${{\overline{\mathit b}}^{\,'}}$ $\rightarrow$ ${{\mathit H}}{{\mathit b}}{+}$ ${{\mathit X}}$ searches.
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24
AAD 2015CN based on 20.3 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 8 TeV. Limit on pair-production of chiral ${{\mathit b}^{\,'}}$-quark. Used events with ${{\mathit \ell}}$ + $\not E_T$ + ${}\geq{}$4j (non-${{\mathit b}}$-tagged). Limits on a heavy vector-like quark, which decays into ${{\mathit W}}$ ${{\mathit q}}$ , ${{\mathit Z}}{{\mathit q}}$ , ${{\mathit h}}{{\mathit q}}$ , are presented in the plane B( ${{\mathit Q}}$ $\rightarrow$ ${{\mathit W}}{{\mathit q}}$ ) vs. B( ${{\mathit Q}}$ $\rightarrow$ ${{\mathit h}}{{\mathit q}}$ ) in Fig. 12.
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25
Based on 1.04 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 7 TeV. No signal is found for the search of heavy quark pair production that decay into ${{\mathit W}}$ and a ${{\mathit t}}$ quark in the events with a high $p_T$ isolated lepton, large $\not E_T$, and at least 6 jets in which one, two or more dijets are from ${{\mathit W}}$.
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26
Based on 2.0 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 7 TeV. No ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit b}}$ invariant mass peak is found in the search of heavy quark pair production that decay into ${{\mathit Z}}$ and a ${{\mathit b}}$ quark in events with ${{\mathit Z}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$ and at least one ${{\mathit b}}$-jet. The lower mass limit is 358 GeV for a vector-like singlet ${{\mathit b}^{\,'}}$ mixing solely with the third SM generation.
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27
Based on 1.04 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 7 TeV. No signal is found for the search of heavy quark pair production that decay into ${{\mathit W}}$ and a quark in the events with dileptons, large $\not E_T$, and ${}\geq{}$2 jets.
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28
Based on 1.04 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 7 TeV. AAD 2012BE looked for events with two isolated like-sign leptons and at least 2 jets, large $\not E_T$ and H$_{T}$ $>$ 350 GeV.
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29
Based on 5 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 7 TeV. CHATRCHYAN 2012BH searched for QCD and EW production of single and pair of degenerate 4'th generation quarks that decay to ${{\mathit b}}{{\mathit W}}$ or ${{\mathit t}}{{\mathit W}}$ . Absence of signal in events with one lepton, same-sign dileptons or tri-leptons gives the bound. With a mass difference of 25 GeV/c${}^{2}$ between ${\mathit m}_{{{\mathit t}^{\,'}}}$ and ${\mathit m}_{{{\mathit b}^{\,'}}}$, the corresponding limit shifts by about $\pm20$ GeV/c${}^{2}$.
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30
Based on 4.9 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 7 TeV. CHATRCHYAN 2012X looked for events with trileptons or same-sign dileptons and at least one ${{\mathit b}}$ jet.
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31
Based on 4.8 fb${}^{-1}$ of data in ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at 1.96 TeV. AALTONEN 2011J looked for events with ${{\mathit \ell}}$ + $\not E_T$ + ${}\geq{}$5j (${}\geq{}$1 ${{\mathit b}}$ or ${{\mathit c}}$). No signal is observed and the bound ${\mathit \sigma (}$ ${{\mathit b}^{\,'}}{{\overline{\mathit b}}^{\,'}}{)}$ $<$ 30 fb for ${\mathit m}_{{{\mathit b}^{\,'}}}$ $>$ 375 GeV is found for B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit W}}{{\mathit t}}$ ) = 1.
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32
Based on 34 pb${}^{-1}$ of data in ${{\mathit p}}{{\mathit p}}$ collisions at 7 TeV. CHATRCHYAN 2011L looked for multi-jet events with trileptons or same-sign dileptons. No excess above the SM background excludes ${\mathit m}_{{{\mathit b}^{\,'}}}$ between 255 and 361 GeV at 95$\%$ CL for B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit W}}{{\mathit t}}$ ) = 1.
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33
Based on 2.7 fb${}^{-1}$ of data in ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV. AALTONEN 2010H looked for pair production of heavy quarks which decay into ${{\mathit t}}{{\mathit W}^{-}}$ or ${{\mathit t}}{{\mathit W}^{+}}$ , in events with same sign dileptons (${{\mathit e}}$ or ${{\mathit \mu}}$), several jets and large missing $\mathit E_{T}$. The result is obtained for ${{\mathit b}^{\,'}}$ which decays into ${{\mathit t}}{{\mathit W}^{-}}$ . For the charge 5/3 quark (${{\mathit T}_{{5/3}}}$) which decays into ${{\mathit t}}{{\mathit W}^{+}}$ , ${\mathit m}_{{{\mathit T}_{{5/3}}}}$ $>$ 365 GeV (95$\%$ CL) is found when it has the charge $-1$/3 partner B of the same mass.
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34
FLACCO 2010 result is obtained from AALTONEN 2010H result of ${\mathit m}_{{{\mathit b}^{\,'}}}>$ 338 GeV, by relaxing the condition B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit W}}{{\mathit t}}$ ) = 100$\%$ when ${\mathit m}_{{{\mathit b}^{\,'}}}>$ ${\mathit m}_{{{\mathit t}^{\,'}}}$.
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35
Result is based on 1.06 fb${}^{-1}$ of data. No excess from the SM ${{\mathit Z}}$+jet events is found when ${{\mathit Z}}$ decays into ${{\mathit e}}{{\mathit e}}$ or ${{\mathit \mu}}{{\mathit \mu}}$ . The ${\mathit m}_{{{\mathit b}^{\,'}}}$ bound is found by comparing the resulting upper bound on ${\mathit \sigma (}$ ${{\mathit b}^{\,'}}{{\overline{\mathit b}}^{\,'}}{)}$ [1-(1-B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit b}}$ ))${}^{2}$] and the LO estimate of the ${{\mathit b}^{\,'}}$ pair production cross section shown in Fig. 38 of the article.
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36
HUANG 2008 reexamined the ${{\mathit b}^{\,'}}$ mass lower bound of 268 GeV obtained in AALTONEN 2007C that assumes B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit b}}$ ) = 1, which does not hold for ${\mathit m}_{{{\mathit b}^{\,'}}}$ $>$ 255 GeV. The lower mass bound is given in the plane of sin$^2(\theta _{ {{\mathit t}} {{\mathit b}^{\,'}} })$ and ${\mathit m}_{{{\mathit b}^{\,'}}}$.
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37
AFFOLDER 2000 looked for ${{\mathit b}^{\,'}}$ that decays in to ${{\mathit b}}+{{\mathit Z}}$. The signal searched for is ${{\mathit b}}{{\mathit b}}{{\mathit Z}}{{\mathit Z}}$ events where one ${{\mathit Z}}$ decays into ${{\mathit e}^{+}}{{\mathit e}^{-}}$ or ${{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$ and the other ${{\mathit Z}}$ decays hadronically. The bound assumes B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit b}}$ )= 100$\%$. Between 100 GeV and 199 GeV, the 95$\%$CL upper bound on $\sigma\mathrm {( {{\mathit b}^{\,'}} \rightarrow {{\overline{\mathit b}}^{\,'}} )}{\times }B{}^{2}$( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit b}}$ ) is also given (see their Fig.$~$2).
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38
ABE 1998N looked for ${{\mathit Z}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$ decays with displaced vertices. Quoted limit assumes B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit b}}$ )=1 and ${{\mathit c}}{{\mathit \tau}_{{\mathit ^{'}}}}$ =1$~$cm. The limit is lower than ${\mathit m}_{{{\mathit Z}}}+{\mathit m}_{{{\mathit b}}}$ ($\sim{}$96 GeV) if ${{\mathit c}}{{\mathit \tau}}$ $>22~$cm or ${{\mathit c}}{{\mathit \tau}}$ $<0.009~$cm. See their Fig.$~$4.
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39
ABACHI 1997D searched for ${{\mathit b}^{\,'}}$ that decays mainly via FCNC. They obtained 95$\%$CL upper bounds on B( ${{\mathit b}^{\,'}}$ ${{\overline{\mathit b}}^{\,'}}$ $\rightarrow$ ${{\mathit \gamma}}$ + 3 jets) and B( ${{\mathit b}^{\,'}}$ ${{\overline{\mathit b}}^{\,'}}$ $\rightarrow$ 2 ${{\mathit \gamma}}$ + 2 jets), which can be interpreted as the lower mass bound ${\mathit m}_{{{\mathit b}^{\,'}}}>{\mathit m}_{{{\mathit Z}}}+{\mathit m}_{{{\mathit b}}}$.
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40
ABACHI 1995F bound on the top-quark also applies to ${{\mathit b}^{\,'}}$ and ${{\mathit t}^{\,'}}$ quarks that decay predominantly into ${{\mathit W}}$. See FROGGATT 1997 .
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41
MUKHOPADHYAYA 1993 analyze CDF dilepton data of ABE 1992G in terms of a new quark decaying via flavor-changing neutral current. The above limit assumes B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit b}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$ )=1$\%$. For an exotic quark decaying only via virtual ${{\mathit Z}}$ [B( ${{\mathit b}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$ ) = 3$\%$], the limit is 85 GeV.
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42
ABE 1992 dilepton analysis limit of $>$85 GeV at CL=95$\%$ also applies to ${{\mathit b}^{\,'}}$ quarks, as discussed in ABE 1990B.
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43
ABE 1990B exclude the region 28$-$72 GeV.
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44
AKESSON 1990 searched for events having an electron with $\mathit p_{\mathit T}$ $>$ 12 GeV, missing momentum $>$ 15 GeV, and a jet with $\mathit E_{\mathit T}$ $>$ 10 GeV, $\vert \eta \vert $ $<$ $2.2$, and excluded ${\mathit m}_{{{\mathit b}^{\,'}}}$ between 30 and 69 GeV.
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45
For the reduction of the limit due to non-charged-current decay modes, see Fig.$~$19 of ALBAJAR 1990B.
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46
ALBAJAR 1988 study events at $\mathit E_{{\mathrm {cm}}}$ = 546 and 630 GeV with a muon or isolated electron, accompanied by one or more jets and find agreement with Monte Carlo predictions for the production of charm and bottom, without the need for a new quark. The lower mass limit is obtained by using a conservative estimate for the ${{\mathit b}^{\,'}}{{\overline{\mathit b}}^{\,'}}$ production cross section and by assuming that it cannot be produced in ${{\mathit W}}$ decays. The value quoted here is revised using the full $\mathit O(\alpha {}^{3}_{\mathit s}$) cross section of ALTARELLI 1988 .
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