pdgLive

CMS

$\mathit C_{kk}$ in ${{\mathit \ell}}{{\mathit \ell}}$ + ${}\geq{}$2j (${}\geq{}1{{\mathit b}}$)

$1.13$ $\pm0.32$ $\pm0.32$ ${}^{+0.10}_{-0.13}$

CMS

$\mathit C_{rr}$ in ${{\mathit \ell}}{{\mathit \ell}}$ + ${}\geq{}$2j (${}\geq{}1{{\mathit b}}$)

$1.01$ $\pm0.04$ $\pm0.05$ $\pm0.01$

CMS

$\mathit C_{nn}$ in ${{\mathit \ell}}{{\mathit \ell}}$ + ${}\geq{}$2j (${}\geq{}1{{\mathit b}}$)

$0.94$ $\pm0.17$ $\pm0.26$ $\pm0.01$

CMS

$\mathit C_{rk}+\mathit C_{kr}$ in ${{\mathit \ell}}{{\mathit \ell}}$ + ${}\geq{}$2j (${}\geq{}1{{\mathit b}}$)

$0.98$ $\pm0.03$ $\pm0.04$ $\pm0.01$

CMS

($\mathit C_{kk}+\mathit C_{rr}+\mathit C_{nn})/$3 in ${{\mathit \ell}}{{\mathit \ell}}$ + ${}\geq{}$2j (${}\geq{}1{{\mathit b}}$)

$0.74$ $\pm0.07$ $\pm0.19$ ${}^{+0.06}_{-0.08}$

CMS

$\mathit A{}^{lab}_{cos \phi }$ in ${{\mathit \ell}}{{\mathit \ell}}$ +${}\geq{}$2j (${}\geq{}1{{\mathit b}}$)

$1.05$ $\pm0.03$ $\pm0.08$ ${}^{+0.09}_{-0.12}$

CMS

$\mathit A_{\vert \Delta \phi ( {{\mathit \ell}} {{\mathit \ell}} )\vert }$ in ${{\mathit \ell}}{{\mathit \ell}}$ + ${}\geq{}$2j (${}\geq{}1{{\mathit b}}$)

$1.12$ ${}^{+0.12}_{-0.15}$

2016

CMS

${{\mathit \ell}}{{\mathit \ell}}$ + ${}\geq{}$2j (${}\geq{}1{{\mathit b}}$)

$0.72$ $\pm0.08$ ${}^{+0.15}_{-0.13}$

2016

CMS

${{\mathit \mu}}$ + 4,5j

$1.20$ $\pm0.05$ $\pm0.13$

⁴

2015

ATLS

$\Delta \phi $( ${{\mathit \ell}}{{\mathit \ell}}$ ) in ${{\mathit \ell}}{{\mathit \ell}}+{}\geq{}$2j(${}\geq{}1{{\mathit b}}$)

$1.19$ $\pm0.09$ $\pm0.18$

⁵

ATLS

$\Delta \phi $( ${{\mathit \ell}}{{\mathit \ell}}$ ) in ${{\mathit \ell}}{{\mathit \ell}}$ + ${}\geq{}$2j events

$1.12$ $\pm0.11$ $\pm0.22$

⁵

ATLS

$\Delta \phi $( ${{\mathit \ell}}{{\mathit j}}$ ) in ${{\mathit \ell}}$ + ${}\geq{}$4j events

$0.87$ $\pm0.11$ $\pm0.14$

⁵ ^{, 6}

ATLS

S-ratio in ${{\mathit \ell}}{{\mathit \ell}}$ + ${}\geq{}$2j events

$0.75$ $\pm0.19$ $\pm0.23$

⁵ ^{, 7}

ATLS

cos$\theta ({{\mathit \ell}^{+}}$)cos$\theta ({{\mathit \ell}^{-}}$) in ${{\mathit \ell}}{{\mathit \ell}}$ + ${}\geq{}$2j events

$0.83$ $\pm0.14$ $\pm0.18$

⁵ ^{, 8}

ATLS

cos$\theta ({{\mathit \ell}^{+}}$)cos$\theta ({{\mathit \ell}^{-}}$) in ${{\mathit \ell}}{{\mathit \ell}}$ + ${}\geq{}$2j events

SIRUNYAN 2019BX based on 35.9 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 13 TeV. A set of parton-level normalized differential cross sections sensitive to coefficients of the spin-dependent ${{\mathit t}}{{\overline{\mathit t}}}$ production density matrix is measured. The distributions and coefficients are compared with the NLO MC simulations and with the NLO QCD calculation including EW corrections. Three errors are from statistics, experimental systematics, and theory.

²	KHACHATRYAN 2016AI based on 19.5 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 8 TeV, using lepton angular distributions as a function of the ${{\mathit t}}{{\overline{\mathit t}}}$ -system kinematical variables.

³	KHACHATRYAN 2016X based on 19.7 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 8 TeV. Uses a template fit method. Spin correlation strength in the helicity basis is given by $\mathit A_{{\mathrm {hel}}}$ = $0.23$ $\pm0.03$ ${}^{+0.05}_{-0.04}$.

⁴

AAD 2015J based on 20.3 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ = 8 TeV. Uses a fit including a linear superposition of ${{\mathit \Delta}}{{\mathit \phi}}$ distribution from the SM NLO simulation with coefficient ${{\mathit f}_{{SM}}}$ and from ${{\mathit t}}{{\overline{\mathit t}}}$ simulation without spin correlation with coefficient (1 $−$ ${{\mathit f}_{{SM}}}$).

⁵	Based on 4.6 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ data at $\sqrt {s }$ =7 TeV. The results are for ${\mathit m}_{{{\mathit t}}}$ = 172.5 GeV.

⁶	The S-ratio is defined as the SM spin correlation in the like-helicity gluon-gluon collisions normalized to the no spin correlation case; see eq.(6) for the LO expression.

⁷	The polar angle correlation along the helicity axis.

⁸	The polar angle correlation along the direction which maximizes the correlation.

References:

2019BX

PR D100 072002

Measurement of the top quark polarization and $\mathrm{t\bar{t}}$ spin correlations using dilepton final states in proton-proton collisions at $\sqrt{s} =$ 13 TeV

2016AI

PR D93 052007

Measurements of ${\mathit {\mathit t}}{\mathit {\overline{\mathit t}}}$ Spin Correlations and Top Quark Polarization using Dilepton Final States in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8 TeV

2016X

PL B758 321

Measurement of Spin Correlations in ${\mathit {\mathit t}}{\mathit {\overline{\mathit t}}}$ Production using the Matrix Element Method in the Muon+Jets Final State in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8 TeV

2015J

PRL 114 142001

Measurement of Spin Correlation in Top-Antitop Quark Events and Search for Top Squark Pair Production in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8 TeV Using the ATLAS Detector