pdgLive

TRIPLE GAUGE COUPLINGS (TGC'S)

$\lambda _{{{\mathit Z}}}$

INSPIRE JSON (beta) PDGID:

This coupling is $\mathit CP$-conserving ($\mathit C$- and $\mathit P$- separately conserving).

VALUE

EVTS

DOCUMENT ID

TECN

COMMENT

$-0.088$ ${}^{+0.060}_{-0.057}$ $\pm0.023$

7171

L3

${\it{}E}^{\it{}ee}_{\rm{}cm}$ = $189 - 209$ GeV

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

CMS

${\it{}E}^{\it{}pp}_{\rm{}cm}$ = 13 TeV

CMS

${\it{}E}^{\it{}pp}_{\rm{}cm}$ = 13 TeV

CMS

${\it{}E}^{\it{}pp}_{\rm{}cm}$ = 13 TeV

ATLS

${\it{}E}^{\it{}pp}_{\rm{}cm}$ = 7+8 TeV

ATLS

${\it{}E}^{\it{}pp}_{\rm{}cm}$ = 8 TeV

CMS

${\it{}E}^{\it{}pp}_{\rm{}cm}$ = 8 TeV

CMS

${\it{}E}^{\it{}pp}_{\rm{}cm}$ = 8 TeV

ATLS

${\it{}E}^{\it{}pp}_{\rm{}cm}$ = 8 TeV

ATLS

${\it{}E}^{\it{}pp}_{\rm{}cm}$ = 8 TeV

ATLS

${\it{}E}^{\it{}pp}_{\rm{}cm}$ = 8 TeV

ATLS

${\it{}E}^{\it{}pp}_{\rm{}cm}$ = 7 TeV

CMS

${\it{}E}^{\it{}pp}_{\rm{}cm}$ = 7 TeV

ATLS

${\it{}E}^{\it{}pp}_{\rm{}cm}$ = 7 TeV

CDF

${\it{}E}^{\it{}p\overline{\it{}p}}_{\rm{}cm}$ = 1.96 TeV

34

D0

${\it{}E}^{\it{}p\overline{\it{}p}}_{\rm{}cm}$ = 1.96 TeV

334

CDF

${\it{}E}^{\it{}p\overline{\it{}p}}_{\rm{}cm}$ = 1.96 TeV

13

D0

${\it{}E}^{\it{}p\overline{\it{}p}}_{\rm{}cm}$ = 1.96 TeV

17

D0

${\it{}E}^{\it{}p\overline{\it{}p}}_{\rm{}cm}$ = 1.96 TeV

2.3

D0

${\it{}E}^{\it{}p\overline{\it{}p}}_{\rm{}cm}$ = 1.96 TeV

¹

ACHARD 2004D study $WW-$pair production, single$-{{\mathit W}}$ production and single$-$photon production with missing energy from 189 to 209 GeV. The result quoted here is obtained using the $WW-$pair production sample. Each parameter is determined from a single$-$parameter fit in which the other parameters assume their Standard Model values.

²

SIRUNYAN 2020BA study electroweak production of a ${{\mathit W}}$ boson in association with two jets, using ${{\mathit W}}$ decays in the electron or muon channel. The isolated muons (electrons) are required to have a transverse momentum larger than 25 (30) GeV, while the transverse momentum of the two jets has to be larger than 50 and 30 GeV. A total of 2.382 (1.051) million events are selected in the muon (electron) channel, with a Standard Model expectation of $2.39$ $\pm0.17$ ($1.054$ $\pm0.058$) million events. Analysing the transverse momentum distribution of the charged leptons from ${{\mathit W}}$ decay, the following 95$\%$ C.L. limit is obtained: -0.0088 $<$ ${{\mathit \lambda}_{{{Z}}}}$ $<$ 0.0095. Combining this result with that from the closely-related electroweak Z-jet-jet production SIRUNYAN 2018BZ, the limit becomes: $-0.0071 < \lambda_Z < 0.0076$.

³

SIRUNYAN 2019CL study ${{\mathit W}}{{\mathit W}}$ and ${{\mathit W}}{{\mathit Z}}$ production in lepton + jet events, with one ${{\mathit W}}$ boson decaying leptonically (electron or muon), and another ${{\mathit W}}$ or ${{\mathit Z}}$ boson decaying hadronically, reconstructed as a single massive large-radius jet. In the electron channel 2,456 (2,235) events are selected in the ${{\mathit W}}{{\mathit W}}({{\mathit W}}{{\mathit Z}}$) category, while in the muon channel 3,996 (3572) events are selected in the ${{\mathit W}}{{\mathit W}}({{\mathit W}}{{\mathit Z}}$) category. Analysing the di-boson invariant mass distribution, the following 95$\%$ C.L. limit is obtained: $-0.0065$ $<$ ${{\mathit \lambda}_{{{Z}}}}$ $<$ 0.0066.

⁴

SIRUNYAN 2018BZ study ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit Z}}~\mathit jet~jet$ events at 13 TeV where ${{\mathit Z}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}$ $/$ ${{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$. Isolated electrons and muons are selected with $p_T$ of the leading/sub-leading lepton $>$ 30/20 GeV and $\vert {{\mathit \eta}}\vert $ $<$ 2.4, with the di-lepton invariant mass within 15 GeV of the ${{\mathit Z}}$ mass. The two highest $p_T$ jets are selected with $p_T$ of the leading/sub-leading jet $>$ 50/30 GeV respectively and dijet invariant mass $>$ 200 GeV. Templates in the transverse momentum of the ${{\mathit Z}}$ are utilized to set limits on the triple gauge couplings in the EFT and the LEP parametrizations. The following 95$\%$ C.L. limit is obtained $-0.010$ $<{{\mathit \lambda}_{{{Z}}}}<$ $0.010$.

⁵

AABOUD 2017S analyze electroweak production of a ${{\mathit W}}$ boson in association with two jets at high dijet invariant mass, with the ${{\mathit W}}$ boson decaying to electron or muon plus neutrino. In the signal region of dijet mass larger than 1 TeV and leading-jet transverse momentum larger than 600 GeV, 30 events are observed in the data with $39$ $\pm4$ events expected in the Standard Model, yielding the following limit at 95$\%$ CL for the form factor cut-off scale ${{\mathit \Lambda}_{{{FF}}}}\rightarrow\infty{}$: $-0.053$ $<{{\mathit \lambda}_{{{Z}}}}<$ $0.042$.

⁶

AABOUD 2017U analyze production of ${{\mathit W}}{{\mathit W}}$ or ${{\mathit W}}{{\mathit Z}}$ boson pairs with one ${{\mathit W}}$ boson decaying to electron or muon plus neutrino, and the other ${{\mathit W}}$ or ${{\mathit Z}}$ boson decaying hadronically. The hadronic decay system is reconstructed as either a resolved two-jet system or as a single large jet. Analysing the transverse momentum distribution of the hadronic system above 100 GeV yields the following limit at 95$\%$ CL for the form factor cut-off scale ${{\mathit \Lambda}_{{{FF}}}}\rightarrow\infty{}$: $-0.013$ $<$ ${{\mathit \lambda}_{{{Z}}}}$ $<$ $0.013$.

⁷

KHACHATRYAN 2017O analyse ${{\mathit W}}{{\mathit Z}}$ production where each boson decays into electrons or muons. Events are required to have a tri-lepton invariant mass larger than 100 GeV, with one of the lepton pairs having an invariant mass within 20 GeV of the ${{\mathit Z}}$ boson mass. The ${{\mathit Z}}$ transverse momentum spectrum is analyzed to set a 95$\%$ C.L. limit of: $-0.018$ $<$ ${{\mathit \lambda}_{{{Z}}}}$ $<$ $0.016$.

⁸

SIRUNYAN 2017X study ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit W}}{{\mathit W}}/{{\mathit W}}$ ${{\mathit Z}}$ $\rightarrow$ ${{\mathit \ell}}{{\mathit \nu}}{{\mathit q}}{{\overline{\mathit q}}}$ production at 8 TeV where ${{\mathit \ell}}$ is an electron or muon with $p_T$ $>$ 30 or 25 GeV respectively. Suitable cuts are put on the $p_T$ of the dijet system and the missing $\mathit E_{T}$ of the event yielding a total of 285 and 204 ${{\mathit W}}{{\mathit V}}$ events observed in the electron and muon channels. The following 95$\%$ C.L. limit is obtained: $-0.011$ $<$ ${{\mathit \lambda}_{{{Z}}}}$ $<$ 0.011.

⁹

AAD 2016AR study WW production in ${{\mathit p}}{{\mathit p}}$ collisions and select 6636 ${{\mathit W}}{{\mathit W}}$ candidates in decay modes with electrons or muons with an expected background of $1546$ $\pm157$ events. Assuming the LEP formulation and setting the form-factor $\Lambda $ to infinity, a fit to the transverse momentum distribution of the leading charged lepton, leads to a 95$\%$ C.L. range of $-0.019$ $<{{\mathit \lambda}_{{{Z}}}}<$ 0.019.

¹⁰

AAD 2016P study ${{\mathit W}}{{\mathit Z}}$ production in ${{\mathit p}}{{\mathit p}}$ collisions and select 2091 ${{\mathit W}}{{\mathit Z}}$ candidates in 4 decay modes with electrons and muons, with an expected background of $1825$ $\pm7$ events. Analyzing the ${{\mathit W}}{{\mathit Z}}$ transverse momentum distribution, the resulting 95$\%$ C.L. limit is: $-0.016$ $<{{\mathit \lambda}_{{{Z}}}}<$ 0.016.

¹¹

AAD 2014Y determine the electroweak ${{\mathit Z}}$-dijet cross section in 8 TeV ${{\mathit p}}{{\mathit p}}$ collisions. ${{\mathit Z}}$ $\rightarrow$ ${{\mathit e}}{{\mathit e}}$ and ${{\mathit Z}}$ $\rightarrow$ ${{\mathit \mu}}{{\mathit \mu}}$ decays are selected with the di-lepton $p_T>$ 20 GeV and mass in the $81 - 101$ GeV range. Minimum two jets are required with $p_T>$ 55 and 45 GeV and no additional jets with $p_T>$ 25 GeV in the rapidity interval between them. The normalized $p_T$ balance between the ${{\mathit Z}}$ and the two jets is required to be $<$ 0.15. This leads to a selection of 900 events with dijet mass $>$ 1 TeV. The number of signal and background events expected is 261 and 592 respectively. A Poisson likelihood method is used on an event by event basis to obtain the 95$\%$ CL limit $-0.15$ $<{{\mathit \lambda}_{{{Z}}}}$ $<$ 0.13 for a form factor value $\Lambda $ = $\infty{}$.

¹²

AAD 2013AL study ${{\mathit W}}{{\mathit W}}$ production in ${{\mathit p}}{{\mathit p}}$ collisions and select 1325 ${{\mathit W}}{{\mathit W}}$ candidates in decay modes with electrons or muons with an expected background of $369$ $\pm61$ events. Assuming the LEP formulation and setting the form-factor ${{\mathit \Lambda}}$ = infinity, a fit to the transverse momentum distribution of the leading charged lepton, leads to a 95$\%$ C.L. range of $-0.062$ $<$ ${{\mathit \lambda}_{{{Z}}}}$ $<$ 0.059. Supersedes AAD 2012AC.

¹³

CHATRCHYAN 2013BF determine the ${{\mathit W}^{+}}{{\mathit W}^{-}}$ production cross section using unlike sign di-lepton (${{\mathit e}}$ or ${{\mathit \mu}}$) events with high $\not\!\!p_T$. The leptons have $p_T>$ 20 GeV/c and are isolated. 1134 candidate events are observed with an expected SM background of $247$ $\pm34$. The $p_T$ distribution of the leading lepton is fitted to obtain 95$\%$ C.L. limits of $-0.048$ ${}\leq{}{{\mathit \lambda}_{{{Z}}}}{}\leq{}$ 0.048.

¹⁴

AAD 2012CD study ${{\mathit W}}{{\mathit Z}}$ production in ${{\mathit p}}{{\mathit p}}$ collisions and select 317 ${{\mathit W}}{{\mathit Z}}$ candidates in three ${{\mathit \ell}}{{\mathit \nu}}$ decay modes with an expected background of $68.0$ $\pm10.0$ events. The resulting 95$\%$ C.L. range is: $-0.046$ $<$ ${{\mathit \lambda}_{{{Z}}}}<$ 0.047. Supersedes AAD 2012V.

¹⁵

AALTONEN 2012AC study ${{\mathit W}}{{\mathit Z}}$ production in ${{\mathit p}}{{\overline{\mathit p}}}$ collisions and select 63 ${{\mathit W}}{{\mathit Z}}$ candidates in three ${{\mathit \ell}}{{\mathit \nu}}$ decay modes with an expected background of $7.9$ $\pm1.0$ events. Based on the cross section and shape of the ${{\mathit Z}}$ transverse momentum spectrum, the following 95$\%$ C.L. range is reported: $-0.08$ $<$ ${{\mathit \lambda}_{{{Z}}}}$ $<$ 0.10 for a form factor of $\Lambda $ = 2 TeV.

¹⁶

ABAZOV 2011 study the ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ 3 ${{\mathit \ell}}{{\mathit \nu}}$ process arising in ${{\mathit W}}{{\mathit Z}}$ production. They observe 34 ${{\mathit W}}{{\mathit Z}}$ candidates with an estimated background of 6 events. An analysis of the $p_T$ spectrum of the ${{\mathit Z}}$ boson leads to a 95$\%$ C.L. limit of $-0.077<$ ${{\mathit \lambda}_{{{Z}}}}<$ 0.093, for a form factor $\Lambda $ = 2 TeV.

¹⁷

AALTONEN 10K study ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit W}^{+}}{{\mathit W}^{-}}$ with ${{\mathit W}}$ $\rightarrow$ ${{\mathit e}}/{{\mathit \mu}}{{\mathit \nu}}$. The $p_T$ of the leading (second) lepton is required to be $>$ 20 (10) GeV. The final number of events selected is 654 of which $320$ $\pm47$ are estimated to be background. The 95$\%$ C.L. interval is $-0.16$ $<$ ${{\mathit \lambda}_{{{Z}}}}<$ 0.16 for $\Lambda $ = 1.5 TeV and $-0.14$ $<$ ${{\mathit \lambda}_{{{Z}}}}<$ 0.15 for $\Lambda $ = 2 TeV.

¹⁸

ABAZOV 2007Z set limits on anomalous TGCs using the measured cross section and $p_T({{\mathit Z}}$) distribution in ${{\mathit W}}{{\mathit Z}}$ production with both the ${{\mathit W}}$ and the ${{\mathit Z}}$ decaying leptonically into electrons and muons. Setting the other couplings to their standard model values, the 95$\%$ C.L. limit for a form factor scale $\Lambda $ = 2$~$TeV is $-0.17$ $<{{\mathit \lambda}_{{{Z}}}}<$ 0.21.

¹⁹

ABAZOV 2006H study ${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit W}}{{\mathit W}}$ production with a subsequent decay ${{\mathit W}}$ ${{\mathit W}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit \nu}_{{{e}}}}{{\mathit e}^{-}}{{\overline{\mathit \nu}}_{{{e}}}}$, ${{\mathit W}}$ ${{\mathit W}}$ $\rightarrow$ ${{\mathit e}^{\pm}}{{\mathit \nu}_{{{e}}}}{{\mathit \mu}^{\mp}}{{\mathit \nu}_{{{\mu}}}}$ or ${{\mathit W}}$ ${{\mathit W}}$ $\rightarrow$ ${{\mathit \mu}^{+}}{{\mathit \nu}_{{{\mu}}}}{{\mathit \mu}^{-}}{{\overline{\mathit \nu}}_{{{\mu}}}}$. The 95$\%$ C.L. limit for a form factor scale $\Lambda $ = 2 TeV is $-0.39$ $<\lambda _{Z}<$ 0.39, fixing $\kappa _{Z}$=1. With the assumption that the ${{\mathit W}}{{\mathit W}}{{\mathit \gamma}}$ and ${{\mathit W}}{{\mathit W}}{{\mathit Z}}$ couplings are equal the 95$\%$ C.L. one-dimensional limit ($\Lambda $ = 2 TeV) is $-0.29$ $<\lambda <$ 0.30.

²⁰

ABAZOV 2005S study ${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit W}}{{\mathit Z}}$ production with a subsequent trilepton decay to ${{\mathit \ell}}{{\mathit \nu}}{{\mathit \ell}^{\,'}}{{\overline{\mathit \ell}}^{\,'}}$ (${{\mathit \ell}}$ and ${{\mathit \ell}^{\,'}}$ = ${{\mathit e}}$ or ${{\mathit \mu}}$). Three events (estimated background $0.71$ $\pm0.08$ events) with $WZ$ decay characteristics are observed from which they derive limits on the anomalous couplings. The 95$\%$ CL limit for a form factor scale $\Lambda $ = 1.5 TeV is $-0.48$ $<$ ${{\mathit \lambda}_{{{Z}}}}$ $<$ 0.48, fixing $\mathit g{}^{{{\mathit Z}}}_{1}$ and ${{\mathit \kappa}_{{{Z}}}}$ to their Standard Model values.

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