ANOMALOUS ${{\boldsymbol Z}}{{\boldsymbol Z}}{{\boldsymbol \gamma}}$ , ${{\boldsymbol Z}}{{\boldsymbol \gamma}}{{\boldsymbol \gamma}}$ , AND ${{\boldsymbol Z}}{{\boldsymbol Z}}{{\boldsymbol V}}$ COUPLINGS

$\boldsymbol f{}^{\boldsymbol V}_{\boldsymbol i}$ INSPIRE search

Combining the LEP-2 results taking into account the correlations, the following 95$\%$ CL limits are derived [SCHAEL 2013A]:

$-0.28<$ $\mathit f{}^{{{\mathit Z}}}_{4}<+0.32$, $-0.34<$ $\mathit f{}^{{{\mathit Z}}}_{5}<+0.35$, $-0.17<$ $\mathit f{}^{{{\mathit \gamma}}}_{4}<+0.19$, $-0.35<$ $\mathit f{}^{{{\mathit \gamma}}}_{5}$ $<+0.32$.

Some of the recent results from the Tevatron and LHC experiments individually surpass the combined LEP-2 results in precision (see below).

VALUE DOCUMENT ID TECN  COMMENT
• • • We do not use the following data for averages, fits, limits, etc. • • •
1
KHACHATRYAN
2015B
CMS ${\it{}E}^{\it{}pp}_{\rm{}cm}$ = 8 TeV
2
KHACHATRYAN
2015BC
CMS ${\it{}E}^{\it{}pp}_{\rm{}cm}$ = 7, 8 TeV
3
AAD
2013Z
ATLS ${\it{}E}^{\it{}pp}_{\rm{}cm}$ = 7 TeV
4
CHATRCHYAN
2013B
CMS ${\it{}E}^{\it{}pp}_{\rm{}cm}$ = 7 TeV
5
SCHAEL
2009
ALEP ${\it{}E}^{\it{}ee}_{\rm{}cm}$ = $192 - 209$ GeV
6
ABAZOV
2008K
D0 ${\it{}E}^{\it{}p\overline{\it{}p}}_{\rm{}cm}$ = 1.96 TeV
7
ABDALLAH
2007C
DLPH ${\it{}E}^{\it{}ee}_{\rm{}cm}$ = $183 - 208$ GeV
8
ABBIENDI
2004C
OPAL
9
ACHARD
2003D
L3
1  KHACHATRYAN 2015B study ${{\mathit Z}}{{\mathit Z}}$ production in 8 TeV ${{\mathit p}}{{\mathit p}}$ collisions. In the decay modes ${{\mathit Z}}$ ${{\mathit Z}}$ $\rightarrow$ 4 ${{\mathit e}}$ , 4${{\mathit \mu}}$, 2 ${{\mathit e}}$2 ${{\mathit \mu}}$ , 54, 75, 148 events are observed, with an expected background of $2.2$ $\pm0.9$, $1.2$ $\pm0.6$, and $2.4$ $\pm1.0$ events, respectively. Analysing the 4-lepton invariant mass spectrum in the range from 110 GeV to 1200 GeV, the following 95$\%$ C.L. limits are obtained: $\vert {{\mathit f}}{}^{Z}_{4}\vert $ $<$ 0.004, $\vert {{\mathit f}}{}^{Z}_{5}\vert $ $<$ 0.004, $\vert {{\mathit f}}{}^{{{\mathit \gamma}}}_{4}\vert $ $<$ 0.005, $\vert {{\mathit f}}{}^{{{\mathit \gamma}}}_{5}\vert $ $<$ 0.005.
2  KHACHATRYAN 2015BC use the cross section measurement of the final state ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit Z}}$ $\rightarrow$ 2 ${{\mathit \ell}}$2 ${{\mathit \nu}}$ , (${{\mathit \ell}}$ being an electron or a muon) at 7 and 8 TeV to put limits on these triple gauge couplings. Effective mass of the charged lepton pair is required to be in the range $83.5 - 98.5$ GeV and the dilepton $p_T$ $>$ 45 GeV. The reduced missing $\mathit E_{T}$ is required to be $>$ 65 GeV, which takes into account the fake missing $\mathit E_{T}$ due to detector effects. The numbers of ${{\mathit e}^{+}}{{\mathit e}^{-}}$ and ${{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$ events selected are 35 and 40 at 7 TeV and 176 and 271 at 8 TeV respectively. The production cross sections so obtained are in agreement with SM predictions. The following 95$\%$ C.L. limits are set: $-0.0028$ $<$ ${{\mathit f}_{{4}}^{Z}}$ $<$ 0.0032, $-0.0037$ $<$ ${{\mathit f}}{}^{{{\mathit \gamma}}}_{4}$ $<$ 0.0033, $-0.0029$ $<$ ${{\mathit f}_{{5}}^{Z}}$ $<$ 0.0031, $-0.0033$ $<$ ${{\mathit f}}{}^{{{\mathit \gamma}}}_{5}$ $<$ 0.0037. Combining with previous results (KHACHATRYAN 2015B and CHATRCHYAN 2013B) which include 7 TeV and 8 TeV data on the final states ${{\mathit p}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit Z}}$ $\rightarrow$ 2 ${{\mathit \ell}}$2 ${{\mathit \ell}^{\,'}}$ where ${{\mathit \ell}}$ and ${{\mathit \ell}^{\,'}}$ are an electron or a muon, the best limits are $-0.0022$ $<$ ${{\mathit f}_{{4}}^{Z}}$ $<$ 0.0026, $-0.0029$ $<$ ${{\mathit f}}{}^{{{\mathit \gamma}}}_{4}$ $<$ 0.0026, $-0.0023$ $<$ ${{\mathit f}_{{5}}^{Z}}$ $<$ 0.0023, $-0.0026$ $<$ ${{\mathit f}}{}^{{{\mathit \gamma}}}_{5}$ $<$ 0.0027.
3  AAD 2013Z study ${{\mathit Z}}{{\mathit Z}}$ production in ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV. In the ${{\mathit Z}}$ ${{\mathit Z}}$ $\rightarrow$ ${{\mathit \ell}^{+}}{{\mathit \ell}^{-}}{{\mathit \ell}^{'+}}{{\mathit \ell}^{'-}}$ final state they observe a total of 66 events with an expected background of $0.9$ $\pm1.3$. In the ${{\mathit Z}}$ ${{\mathit Z}}$ $\rightarrow$ ${{\mathit \ell}^{+}}{{\mathit \ell}^{-}}{{\mathit \nu}}{{\mathit \nu}}$ final state they observe a total of 87 events with an expected background of $46.9$ $\pm5.2$. The limits on anomalous TGCs are determined using the observed and expected numbers of these ${{\mathit Z}}{{\mathit Z}}$ events binned in ${{\mathit p}_{{T}}^{Z}}$. The 95$\%$ C.L. are as follows: for form factor scale ${{\mathit \Lambda}}$ = $\infty{}$, $-0.015$ $<$ ${{\mathit f}}{}^{{{\mathit \gamma}}}_{4}$ $<$ 0.015, $-0.013$ $<$ ${{\mathit f}}{}^{Z}_{4}$ $<$ 0.013, $-0.016$ $<$ ${{\mathit f}}{}^{{{\mathit \gamma}}}_{5}$ $<$ 0.015, $-0.013$ $<$ ${{\mathit f}}{}^{Z}_{5}$ $<$ 0.013; for form factor scale ${{\mathit \Lambda}}$ = 3 TeV, $-0.022$ $<$ ${{\mathit f}}{}^{{{\mathit \gamma}}}_{4}$ $<$ 0.023, $-0.019$ $<$ ${{\mathit f}}{}^{Z}_{4}$ $<$ 0.019, $-0.023$ $<$ ${{\mathit f}}{}^{{{\mathit \gamma}}}_{5}$ $<$ 0.023, $-0.020$ $<$ ${{\mathit f}}{}^{Z}_{5}$ $<$ 0.019.
4  CHATRCHYAN 2013B study ${{\mathit Z}}{{\mathit Z}}$ production in ${{\mathit p}}{{\mathit p}}$ collisions and select 54 ${{\mathit Z}}{{\mathit Z}}$ candidates in the ${{\mathit Z}}$ decay channel with electrons or muons with an expected background of $1.4$ $\pm0.5$ events. The resulting 95$\%$ C.L. ranges are: $-0.013$ $<$ ${{\mathit f}}{}^{{{\mathit \gamma}}}_{4}$ $<$ 0.015, $-0.011$ $<$ ${{\mathit f}}{}^{Z}_{4}$ $<$ 0.012, $-0.014$ $<$ ${{\mathit f}}{}^{{{\mathit \gamma}}}_{5}$ $<$ 0.014, $-0.012$ $<$ ${{\mathit f}}{}^{Z}_{5}$ $<$ 0.012.
5  Using data collected in the center of mass energy range $192 - 209$ GeV, SCHAEL 2009 select 318 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit Z}}$ events with 319.4 expected from the standard model. Using this data they derive the following 95$\%$ CL limits: $-0.321<{{\mathit f}}{}^{{{\mathit \gamma}}}_{4}<$ 0.318, $-0.534<{{\mathit f}_{{4}}^{Z}}<$ 0.534, $-0.724<{{\mathit f}}{}^{{{\mathit \gamma}}}_{5}<$ 0.733, $-1.194<{{\mathit f}_{{5}}^{Z}}<$ 1.190.
6  ABAZOV 2008K search for ${{\mathit Z}}{{\mathit Z}}$ and ${{\mathit Z}}{{\mathit \gamma}^{*}}$ events with 1$~$fb${}^{-1}$ ${{\mathit p}}{{\overline{\mathit p}}}$ data at $\sqrt {s }$ = 1.96 TeV in ( ${{\mathit e}}{{\mathit e}}$)( ${{\mathit e}}{{\mathit e}}$), ( ${{\mathit \mu}}{{\mathit \mu}}$)( ${{\mathit \mu}}{{\mathit \mu}}$), ( ${{\mathit e}}{{\mathit e}}$)( ${{\mathit \mu}}{{\mathit \mu}}$) final states requiring the lepton pair masses to be $>$ 30 GeV. They observe 1 event, which is consistent with an expected signal of $1.71$ $\pm0.15$ events and a background of $0.13$ $\pm0.03$ events. From this they derive the following limits, for a form factor ($\Lambda $) value of 1.2 TeV: $-0.28<{{\mathit f}_{{40}}^{Z}}<$ 0.28, $-0.31<{{\mathit f}_{{50}}^{Z}}<$ 0.29, $-0.26<{{\mathit f}_{{40}^#p{gamma}}}<$ 0.26, $-0.30<{{\mathit f}_{{50}^#p{gamma}}}<$ 0.28.
7  Using data collected at $\sqrt {s }$ = $183 - 208$ GeV, ABDALLAH 2007C select 171 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit Z}}$ events with ${{\mathit Z}}$ $\rightarrow$ ${{\mathit q}}{{\overline{\mathit q}}}$ or lepton pair (except an explicit ${{\mathit \tau}}$ pair), and 74 ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit Z}}{{\mathit \gamma}^{*}}$ events with a ${{\mathit q}}{{\overline{\mathit q}}}{{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$ or ${{\mathit q}}{{\overline{\mathit q}}}{{\mathit e}^{+}}{{\mathit e}^{-}}$ signature, to derive 95$\%$ CL limits on ${{\mathit f}_{{i}}^{V}}$. Each limit is derived with other parameters set to zero. They report: $-0.40<{{\mathit f}_{{4}}^{Z}}<$ 0.42, $-0.38<{{\mathit f}_{{5}}^{Z}}<$ 0.62, $-0.23<{{\mathit f}}{}^{{{\mathit \gamma}}}_{4}<$ 0.25, $-0.52<{{\mathit f}}{}^{{{\mathit \gamma}}}_{5}<$ 0.48.
8  ABBIENDI 2004C study ${{\mathit Z}}{{\mathit Z}}$ production in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ collisions in the C.M. energy range $190 - 209$ GeV. They select 340 events with an expected background of 180 events. Including the ABBIENDI 2000N data at 183 and 189 GeV (118 events with an expected background of 65 events) they report the following 95$\%$ CL limits: $-0.45<\mathit f{}^{{{\mathit Z}}}_{4}<0.58$, $-0.94<\mathit f{}^{{{\mathit Z}}}_{5}<0.25$, $-0.32<\mathit f{}^{{{\mathit \gamma}}}_{4}<0.33$, and $-0.71<\mathit f{}^{{{\mathit \gamma}}}_{5}<0.59$.
9  ACHARD 2003D study ${{\mathit Z}}$-boson pair production in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ collisions in the C.M. energy range $200 - 209$ GeV. They select 549 events with an expected background of 432 events. Including the ACCIARRI 1999G and ACCIARRI 1999O data (183 and 189 GeV respectively, 286 events with an expected background of 241 events) and the $192 - 202$ GeV ACCIARRI 2001I results (656 events, expected background of 512 events), they report the following 95$\%$ CL limits: $-0.48{}\leq{}\mathit f{}^{{{\mathit Z}}}_{4}{}\leq{}0.46$, $-0.36{}\leq{}\mathit f{}^{{{\mathit Z}}}_{5}{}\leq{}1.03$, $-0.28{}\leq{}\mathit f{}^{{{\mathit \gamma}}}_{4}{}\leq{}0.28$, and $-0.40{}\leq{}\mathit f{}^{{{\mathit \gamma}}}_{5}{}\leq{}0.47$.
  References:
KHACHATRYAN 2015B
PL B740 250 Measurement of the ${{\mathit p}}{{\mathit p}}\rightarrow{{\mathit Z}}{{\mathit Z}}$ Production Cross Section and Constraints on Anomalous Triple Gauge Couplings in Four-Lepton Final States at $\sqrt {s }$ = 8 TeV
KHACHATRYAN 2015BC
EPJ C75 511 Measurements of the ${{\mathit Z}}{{\mathit Z}}$ Production Cross Sections in the 2${{\mathit \ell}}2{{\mathit \nu}}$ Channel in Proton$−$Proton Collisions at $\sqrt {s }$ = 7 and 8 TeV and Combined Constraints on triple Gauge Couplings
AAD 2013Z
JHEP 1303 128 Measurement of ${{\mathit Z}}{{\mathit Z}}$ Production in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 7 TeV and Limits on Anomalous ${{\mathit Z}}{{\mathit Z}}{{\mathit Z}}$ and ${{\mathit Z}}{{\mathit Z}}{{\mathit \gamma}}$ Couplings with the ATLAS Detector
CHATRCHYAN 2013B
JHEP 1301 063 Measurement of the ${{\mathit Z}}{{\mathit Z}}$ Production Cross Section and Search for Anomalous Couplings in 2${{\mathit \ell}}2{{\mathit \ell}^{\,'}}$ Final States in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 7 TeV
SCHAEL 2009
JHEP 0904 124 Measurement of ${{\mathit Z}}$-Pair Production in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions and Constraints on Anomalous Neutral Gauge Couplings
ABAZOV 2008K
PRL 100 131801 Search for ${{\mathit Z}}{{\mathit Z}}$ and ${{\mathit Z}}{{\mathit \gamma}^{*}}$ Production in ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions at $\sqrt {s }$ = 1.96 TeV and Limits on Anomalous ${{\mathit Z}}{{\mathit Z}}{{\mathit Z}}$ and ${{\mathit Z}}{{\mathit Z}}{{\mathit \gamma}^{*}}$ Couplings
ABDALLAH 2007C
EPJ C51 525 Study of Triple-Gauge-Boson Couplings ${{\mathit Z}}{{\mathit Z}}{{\mathit Z}}$ , ${{\mathit Z}}{{\mathit Z}}{{\mathit \gamma}}$ and ${{\mathit Z}}{{\mathit \gamma}}{{\mathit \gamma}}$ at LEP
ABBIENDI 2004C
EPJ C32 303 Study of ${{\mathit Z}}$ Pair Production and Anomalous Couplings in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at $\sqrt {s }$ between 190 GeV and 209 GeV
ACHARD 2003D
PL B572 133 ${{\mathit Z}}$ Boson Pair Production at LEP
ABBIENDI 2000N
PL B476 256 ${{\mathit Z}}$ Boson Pair Production in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at $\sqrt {s }$ = 183 and 189 GeV
ACCIARRI 2001I
PL B497 23 Study of ${{\mathit Z}}$ Boson Pair Production in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Interactions at $\sqrt {s }$ = 192-202-GeV
ACCIARRI 1999G
PL B450 281 Study of Neutral Current Four Fermion and ${{\mathit Z}}{{\mathit Z}}$ Production in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at $\sqrt {s }$ = 183 GeV
ACCIARRI 1999O
PL B465 363 Study of ${{\mathit Z}}$ Boson Pair Production in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at LEP at $\sqrt {s }$ = 189 GeV