pdgLive

ALEP

any decay

• • We do not use the following data for averages, fits, limits, etc. • •

$\text{none 96 - 103}$

ABDALLAH

2007

DLPH

${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit b}}{{\mathit Z}}$ , ${{\mathit c}}{{\mathit W}}$

1993

Quarkonium

$>44.7$

1993

$\Gamma\mathrm {({{\mathit Z}} )}$

$>45$

1991

DLPH

$\Gamma\mathrm {({{\mathit Z}} )}$

$\text{none 19.4 - 28.2}$

VNS

Any decay; event shape

$>45.0$

DLPH

B( ${{\mathit C}}{{\mathit C}}$ ) = 1; event shape

$>44.5$

⁴

DLPH

${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit c}}{{\mathit H}^{-}}$ , ${{\mathit H}^{-}}$ $\rightarrow$ ${{\overline{\mathit c}}}{{\mathit s}}$ , ${{\mathit \tau}^{-}}{{\mathit \nu}}$

$>40.5$

⁵

DLPH

$\Gamma\mathrm {( {{\mathit Z}} \rightarrow hadrons)}$

$>28.3$

TOPZ

B(${\mathrm {FCNC}})=100\%$; isol. ${{\mathit \gamma}}$ or 4 jets

$>41.4$

⁶

OPAL

Any decay; acoplanarity

$>45.2$

⁶

OPAL

B( ${{\mathit C}}{{\mathit C}}$ ) = 1; acoplanarity

$>46$

⁷

OPAL

${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit \gamma}}{+}$ any

$>27.5$

⁸

VNS

B( ${{\mathit C}}{{\mathit C}}$ ) =1; ${{\mathit \mu}}$ , ${{\mathit e}}$

$\text{none 11.4 - 27.3}$

⁹

VNS

B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit b}}{{\mathit \gamma}}$ ) $>$ 10$\%$; isolated ${{\mathit \gamma}}$

$>44.7$

¹⁰

MRK2

B( ${{\mathit C}}{{\mathit C}}$ )= 100$\%$; isol. track

$>42.7$

¹⁰

MRK2

B( ${{\mathit b}}{{\mathit g}}$ )= 100$\%$; event shape

$>42.0$

¹⁰

MRK2

Any decay; event shape

$>28.4$

¹¹ ^{, 12}

TOPZ

B( ${{\mathit C}}{{\mathit C}}$ ) =1; ${{\mathit \mu}}$

$>28.8$

¹³

AMY

B( ${{\mathit C}}{{\mathit C}}$ ) ${ {}\gtrsim{} }90\%$; ${{\mathit \mu}}$ , ${{\mathit e}}$

$>27.2$

¹³ ^{, 14}

AMY

any decay; event shape

$>29.0$

¹³

AMY

B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit b}}{{\mathit g}}$ ) ${ {}\gtrsim{} }$ 85$\%$; event shape

$>24.4$

¹⁵

IGARASHI

AMY

${{\mathit \mu}}$ ,${{\mathit e}}$

$>23.8$

¹⁶

SAGAWA

AMY

event shape

$>22.7$

¹⁷

ADEVA

1986

MRKJ

${{\mathit \mu}}$

$>21$

¹⁸

1984

TASS

$\mathit R$, event shape

$>19$

¹⁹

1984

TASS

Aplanarity

DECAMP 1990F looked for isolated charged particles, for isolated photons, and for four-jet final states. The modes ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit b}}{{\mathit g}}$ for B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit b}}{{\mathit g}}$ ) $>$ 65$\%$ ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit b}}{{\mathit \gamma}}$ for B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit b}}{{\mathit \gamma}}$ ) $>$ 5$\%$ are excluded. Charged Higgs decay were not discussed.

ABDALLAH 2007 searched for ${{\mathit b}^{\,'}}$ pair production at $\mathit E_{{\mathrm {cm}}}=196 - 209$ GeV, with 420$~$pb${}^{-1}$. No signal leads to the 95$\%$ CL upper limits on B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit b}}{{\mathit Z}}$ ) and B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit c}}{{\mathit W}}$ ) for ${\mathit m}_{{{\mathit b}^{\,'}}}$ = 96 to 103 GeV.

ADRIANI 1993G search for vector quarkonium states near ${{\mathit Z}}$ and give limit on quarkonium-${{\mathit Z}}$ mixing parameter $\delta {{\mathit m}^{2}}_{}<(10 - 30$) GeV${}^{2}$ (95$\%$CL) for the mass $88 - 94.5$ GeV. Using Richardson potential, a 1S ( ${{\mathit b}^{\,'}}{{\overline{\mathit b}}^{\,'}}$ ) state is excluded for the mass range $87.7 - 94.7$ GeV. This range depends on the potential choice.

⁴	ABREU 1990D assumed ${\mathit m}_{{{\mathit H}^{-}}}$ $<$ ${\mathit m}_{{{\mathit b}^{\,'}}}$ $−$ 3 GeV.

⁵	Superseded by ABREU 1991F.

⁶

AKRAWY 1990B search was restricted to data near the ${{\mathit Z}}$ peak at $\mathit E_{{\mathrm {cm}}}$ = $91.26$ GeV at LEP. The excluded region is between $23.6$ and $41.4$ GeV if no ${{\mathit H}^{+}}$ decays exist. For charged Higgs decays the excluded regions are between (${\mathit m}_{{{\mathit H}^{+}}}$ $+1.5$ GeV) and $45.5$ GeV.

⁷

AKRAWY 1990J search for isolated photons in hadronic ${{\mathit Z}}$ decay and derive B( ${{\mathit Z}}$ $\rightarrow$ ${{\mathit b}^{\,'}}{{\overline{\mathit b}}^{\,'}}$ )$\cdot{}$B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit \gamma}}$ X)/B( ${{\mathit Z}}$ $\rightarrow$ hadrons) $<$ $2.2 \times 10^{-3}$. Mass limit assumes B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit \gamma}}$ X) $>$ 10$\%$.

⁸	ABE 1989E search at $\mathit E_{{\mathrm {cm}}}$ = 56$-$57 GeV at TRISTAN for multihadron events with a spherical shape (using thrust and acoplanarity) or containing isolated leptons.

⁹	ABE 1989G search was at $\mathit E_{{\mathrm {cm}}}$ = 55$-60.8$ GeV at TRISTAN.

¹⁰

If the photonic decay mode is large (B( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit b}}{{\mathit \gamma}}$ ) $>$ 25$\%$), the ABRAMS 1989C limit is $45.4$ GeV. The limit for for Higgs decay ( ${{\mathit b}^{\,'}}$ $\rightarrow$ ${{\mathit c}}{{\mathit H}^{-}}$ , ${{\mathit H}^{-}}$ $\rightarrow$ ${{\overline{\mathit c}}}{{\mathit s}}$ ) is $45.2$ GeV.

¹¹	ADACHI 1989C search was at $\mathit E_{{\mathrm {cm}}}$ = $56.5-60.8$ GeV at TRISTAN using multi-hadron events accompanying muons.

¹²	ADACHI 1989C also gives limits for any mixture of ${{\mathit C}}{{\mathit C}}$ and ${{\mathit b}}{{\mathit g}}$ decays.

¹³	ENO 1989 search at $\mathit E_{{\mathrm {cm}}}$ = 50$-60.8$ at TRISTAN.

¹⁴	ENO 1989 considers arbitrary mixture of the charged current, ${{\mathit b}}{{\mathit g}}$ , and ${{\mathit b}}{{\mathit \gamma}}$ decays.

¹⁵	IGARASHI 1988 searches for leptons in low-thrust events and gives $\Delta \mathit R({{\mathit b}^{\,'}}$ ) $<$ $0.26$ (95$\%$ CL) assuming charged current decay, which translates to ${\mathit m}_{{{\mathit b}^{\,'}}}$ $>$ $24.4$ GeV.

¹⁶

SAGAWA 1988 set limit ${\mathit \sigma (}$top${)}$ $<$ 6.1 pb at CL=95$\%$ for top-flavored hadron production from event shape analyses at $\mathit E_{{\mathrm {cm}}}$ = 52 GeV. By using the quark parton model cross-section formula near threshold, the above limit leads to lower mass bounds of 23.8 GeV for charge $−$1/3 quarks.

¹⁷	ADEVA 1986 give 95$\%$CL upper bound on an excess of the normalized cross section, $\Delta \mathit R$, as a function of the minimum c.m. energy (see their figure 3). Production of a pair of 1/3 charge quarks is excluded up to $\mathit E_{{\mathrm {cm}}}$ = 45.4 GeV.

¹⁸	ALTHOFF 1984C narrow state search sets limit $\Gamma\mathrm {( {{\mathit e}^{+}} {{\mathit e}^{-}} )}{}$B(hadrons) $<$2.4 keV CL = 95$\%$ and heavy charge 1/3 quark pair production $\mathit m$ $>$21 GeV, CL = 95$\%$.

¹⁹	ALTHOFF 1984I exclude heavy quark pair production for 7 $<\mathit m$ $<$19 GeV (1/3 charge) using aplanarity distributions (CL = 95$\%$).

References:

ABDALLAH

2007

EPJ C50 507

Search for a Fourth Generation ${\mathit {\mathit b ^{\prime}}}$-Quark at LEP-II at $\sqrt {s }$ = $196 - 209$ GeV

1993G

PL B313 326

Search for Narrow Vector Resonances in the ${{\mathit Z}^{0}}$ Mass Range

1993M

PRPL 236 1

Results from the L3 Experiment at LEP

1991F

NP B367 511

Determination of ${{\mathit Z}^{0}}$ Resonance Parameters and Couplings from its Hadronic and Leptonic Decays

1990D

PL B234 382

Measurement of R and Search for New Quark Flavors Decaying into Multijet Final States in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions between 54 GeV and 64.1 GeV

1990D

PL B242 536

Search for ${\mathit {\mathit t}}$ and ${\mathit {\mathit b ^{\prime}}}$ Quarks in Hadronic Decays of the ${{\mathit Z}^{0}}$ Boson

PL B234 197

A Search for a ${\mathit {\mathit b ^{\prime}}}$ Quark with Flavor Changing Neutral Current Decay Modes at TRISTAN

1990B

PL B236 364

A Search for the ${\mathit {\mathit t}}$ and ${\mathit {\mathit b ^{\prime}}}$ Quarks in Hadronic ${{\mathit Z}^{0}}$ Decays

1990J

PL B246 285

Evidence for Final State Photons in Multihadronic Decays of the ${{\mathit Z}^{0}}$

DECAMP

1990F

PL B236 511

A Search for New Quarks and Leptons from ${{\mathit Z}^{0}}$ Decay

1989G

PRL 63 1776

Search for Isolated Photons from Flavor-Changing Neutral-Current Decay of a New Quark at the KEK ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ Collider TRISTAN

1989E

PR D39 3524

Search for a Fourth Generation Quark with $\mathit q$ = $\mathit e$/3 in ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ Collisions at $\sqrt {s }$ = 56-57 GeV

1989C

PRL 63 2447

Searches for New Quarks and Leptons Produced in ${{\mathit Z}^{0}}$ Boson Decay

1989C

PL B229 427

A Search for a Fourth Generation Charge -1/3 (${\mathit {\mathit b ^{\prime}}}$) Quark Using Inclusive Muons in ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ Annihilations at $\sqrt {s }$ = 5

PRL 63 1910

Search for a Fourth Generation Charge -1/3 Quark

IGARASHI

PRL 60 2359

Search for Isolated Leptons in Low Thrust ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ Annihilation Events at $\sqrt {s }$ = 50 and 52 GeV

SAGAWA

PRL 60 93

Measurements of $\mathit R$ and a Search for Heavy Quark Production in ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ Annihilation at $\sqrt {s }$ = 50 and 52 GeV

ADEVA

1986

PR D34 681

Study of Hadron and Inclusive Muon Production from ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ Annihilation at 39.79 ${}\leq{}$ $\mathit E_{{\mathrm {cm}}}{}\leq{}$ 46.78 GeV

1984I

ZPHY C22 307

Jet Production and Fragmentation in ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ Annihilation at 12-43 GeV