Measurements of $${\mathrm{p}} {\mathrm{p}} \rightarrow {\mathrm{Z}} {\mathrm{Z}} $$ p p → Z Z production cross sections and constraints on anomalous triple gauge couplings at $$\sqrt{s} = 13\,\text {TeV} $$ s = 13 TeV

Abstract

Abstract The production of Z boson pairs in proton–proton (

$${\mathrm{p}} {\mathrm{p}} $$

p p

) collisions,

$${{\mathrm{p}} {\mathrm{p}} \rightarrow ({\mathrm{Z}}/\gamma ^*)({\mathrm{Z}}/\gamma ^*) \rightarrow 2\ell 2\ell '}$$

p p →

( Z /

γ ∗

)

( Z /

γ ∗

)

→ 2 ℓ 2

ℓ ′

, where

$${\ell ,\ell ' = {\mathrm{e}}}$$

ℓ ,

ℓ ′

= e

or

$${{\upmu }}$$

μ

, is studied at a center-of-mass energy of 13

$$\,\text {TeV}$$

TeV

with the CMS detector at the CERN LHC. The data sample corresponds to an integrated luminosity of 137

$$\,\text {fb}^{-1}$$

fb

- 1

, collected during 2016–2018. The

$${\mathrm{Z}} {\mathrm{Z}} $$

Z Z

production cross section,

$$\sigma _{\text {tot}} ({\mathrm{p}} {\mathrm{p}} \rightarrow {\mathrm{Z}} {\mathrm{Z}} ) = 17.4 \pm 0.3 \,\text {(stat)} \pm 0.5 \,\text {(syst)} \pm 0.4 \,\text {(theo)} \pm 0.3 \,\text {(lumi)} \text { pb} $$

σ tot

( p p → Z Z )

= 17.4 ± 0.3

(stat) ± 0.5

(syst) ± 0.4

(theo) ± 0.3

(lumi) pb

, measured for events with two pairs of opposite-sign, same-flavor leptons produced in the mass region

$${60< m_{\ell ^+\ell ^-} < 120\,\text {GeV}}$$

60 <

m

ℓ +

ℓ -

< 120

GeV

is consistent with standard model predictions. Differential cross sections are also measured and agree with theoretical predictions. The invariant mass distribution of the four-lepton system is used to set limits on anomalous

$${\mathrm{Z}} {\mathrm{Z}} {\mathrm{Z}} $$

Z Z Z

and

$${{\mathrm{Z}} {\mathrm{Z}} \gamma }$$

Z Z γ

couplings.