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Measurements of $t \bar t$ charge asymmetry using dilepton final states in pp collisions at $\sqrt s=8$ TeV

The CMS collaboration
Phys.Lett. B760 (2016) 365-386, 2016

Abstract (data abstract)
The charge asymmetry in $\mathrm{t\bar{t}}$ events is measured using dilepton final states produced in pp collisions at the LHC at $\sqrt{s}=8\:$TeV. The data sample, collected with the CMS detector, corresponds to an integrated luminosity of 19.5 inverse femtobarns. The measurements are performed using events with two oppositely charged leptons (electrons or muons) and two or more jets, where at least one of the jets is identified as originating from a bottom quark. The charge asymmetry is measured from differences in kinematic distributions, unfolded to the parton level, of positively and negatively charged top quarks and leptons. The $\mathrm{t\bar{t}}$ and leptonic charge asymmetries are found to be 0.011 +/- 0.011 (stat) +/- 0.007 (syst) and 0.003 +/- 0.006 (stat) +/- 0.003 (syst), respectively. These results, as well as charge asymmetry measurements made as a function of $\mathrm{t\bar{t}}$ system kinematic properties, are in agreement with predictions of the standard model. For the normalized differential cross sections as a function of $\Delta|y_\mathrm{t}|$ and $\Delta|\eta_{\ell}|$ the distributions are normalized to unit area, i.e. the bin values (and their associated covariances) should be multiplied by the bin widths to give the fraction of events in that bin. For the normalized double-differential cross sections as a function of the $\mathrm{t\bar{t}}$ system variables and $\Delta|y_\mathrm{t}|$ or $\Delta|\eta_{\ell}|$, the quoted bin values (and their associated covariances) are for the fraction of events in that bin, such that the sum of all bin contents is equal to one. The lower and upper $\Delta|y_\mathrm{t}|$ and $\Delta|\eta_{\ell}|$ bins (starting and ending at -2 and +2, respectively) contain underflow and overflow events, i.e. the complete distribution from -infinity to +infinity is covered. Bin values are reported to four decimal places, and covariances to four significant figures. Any missing figures are zeros.

  • Table 1

    Data from Table 2

    10.17182/hepdata.71444.v1/t1

    Inclusive values of the asymmetry variables.

  • Table 2

    Data from Figure 1

    10.17182/hepdata.71444.v1/t2

    Values of the 6 bins of the normalized differential cross section as a function of $\Delta|y_\mathrm{t}|$.

  • Table 3

    Data from Figure 1

    10.17182/hepdata.71444.v1/t3

    Statistical covariance matrix for the 6 bins of the normalized differential cross section as a function of $\Delta|y_\mathrm{t}|$.

  • Table 4

    Data from Figure 1

    10.17182/hepdata.71444.v1/t4

    Systematic covariance matrix for the 6 bins of the normalized differential cross section as a function of $\Delta|y_\mathrm{t}|$.

  • Table 5

    Data from Figure 1

    10.17182/hepdata.71444.v1/t5

    Values of the 12 bins of the normalized differential cross section as a function of $\Delta|\eta_{\ell}|$.

  • Table 6

    Data from Figure 1

    10.17182/hepdata.71444.v1/t6

    Statistical covariance matrix for the 12 bins of the normalized differential cross section as a function of $\Delta|\eta_{\ell}|$.

  • Table 7

    Data from Figure 1

    10.17182/hepdata.71444.v1/t7

    Systematic covariance matrix for the 12 bins of the normalized differential cross section as a function of $\Delta|\eta_{\ell}|$.

  • Table 8

    Data from Figure 2

    10.17182/hepdata.71444.v1/t8

    Values of $A_{\mathrm{C}}$ in the 3 bins of $M_\mathrm{t\bar{t}}$, and inclusively (bottom row). The value 9999 is used as a...

  • Table 9

    Data from Figure 2

    10.17182/hepdata.71444.v1/t9

    Statistical correlation matrix for $A_{\mathrm{C}}$ in the 3 bins of $M_\mathrm{t\bar{t}}$.

  • Table 10

    Data from Figure 2

    10.17182/hepdata.71444.v1/t10

    Systematic correlation matrix for $A_{\mathrm{C}}$ in the 3 bins of $M_\mathrm{t\bar{t}}$.

  • Table 11

    Data from Figure 2

    10.17182/hepdata.71444.v1/t11

    Fraction of events in each of the $6\times3$ bins of the normalized differential cross section as a function of $\Delta|y_\mathrm{t}|$...

  • Table 12

    Data from Figure 2

    10.17182/hepdata.71444.v1/t12

    Statistical covariance matrix for the $6\times3$ bins of the normalized differential cross section as a function of $\Delta|y_\mathrm{t}|$ and $M_\mathrm{t\bar{t}}$.

  • Table 13

    Data from Figure 2

    10.17182/hepdata.71444.v1/t13

    Systematic covariance matrix for the $6\times3$ bins of the normalized differential cross section as a function of $\Delta|y_\mathrm{t}|$ and $M_\mathrm{t\bar{t}}$.

  • Table 14

    Data from Figure 2

    10.17182/hepdata.71444.v1/t14

    Values of $A^{\mathrm{lep}}_{\mathrm{C}}$ in the 3 bins of $M_\mathrm{t\bar{t}}$, and inclusively (bottom row). The value 9999 is used as a...

  • Table 15

    Data from Figure 2

    10.17182/hepdata.71444.v1/t15

    Statistical correlation matrix for $A^{\mathrm{lep}}_{\mathrm{C}}$ in the 3 bins of $M_\mathrm{t\bar{t}}$.

  • Table 16

    Data from Figure 2

    10.17182/hepdata.71444.v1/t16

    Systematic correlation matrix for $A^{\mathrm{lep}}_{\mathrm{C}}$ in the 3 bins of $M_\mathrm{t\bar{t}}$.

  • Table 17

    Data from Figure 2

    10.17182/hepdata.71444.v1/t17

    Fraction of events in each of the $12\times3$ bins of the normalized differential cross section as a function of $\Delta|\eta_{\ell}|$...

  • Table 18

    Data from Figure 2

    10.17182/hepdata.71444.v1/t18

    Statistical covariance matrix for the $12\times3$ bins of the normalized differential cross section as a function of $\Delta|\eta_{\ell}|$ and $M_\mathrm{t\bar{t}}$.

  • Table 19

    Data from Figure 2

    10.17182/hepdata.71444.v1/t19

    Systematic covariance matrix for the $12\times3$ bins of the normalized differential cross section as a function of $\Delta|\eta_{\ell}|$ and $M_\mathrm{t\bar{t}}$.

  • Table 20

    Data from Figure 2

    10.17182/hepdata.71444.v1/t20

    Values of $A_{\mathrm{C}}$ in the 3 bins of $p_\mathrm{T}^\mathrm{t\bar{t}}$, and inclusively (bottom row). The value 9999 is used as a...

  • Table 21

    Data from Figure 2

    10.17182/hepdata.71444.v1/t21

    Statistical correlation matrix for $A_{\mathrm{C}}$ in the 3 bins of $p_\mathrm{T}^\mathrm{t\bar{t}}$.

  • Table 22

    Data from Figure 2

    10.17182/hepdata.71444.v1/t22

    Systematic correlation matrix for $A_{\mathrm{C}}$ in the 3 bins of $p_\mathrm{T}^\mathrm{t\bar{t}}$.

  • Table 23

    Data from Figure 2

    10.17182/hepdata.71444.v1/t23

    Fraction of events in each of the $6\times3$ bins of the normalized differential cross section as a function of $\Delta|y_\mathrm{t}|$...

  • Table 24

    Data from Figure 2

    10.17182/hepdata.71444.v1/t24

    Statistical covariance matrix for the $6\times3$ bins of the normalized differential cross section as a function of $\Delta|y_\mathrm{t}|$ and $p_\mathrm{T}^\mathrm{t\bar{t}}$.

  • Table 25

    Data from Figure 2

    10.17182/hepdata.71444.v1/t25

    Systematic covariance matrix for the $6\times3$ bins of the normalized differential cross section as a function of $\Delta|y_\mathrm{t}|$ and $p_\mathrm{T}^\mathrm{t\bar{t}}$.

  • Table 26

    Data from Figure 2

    10.17182/hepdata.71444.v1/t26

    Values of $A^{\mathrm{lep}}_{\mathrm{C}}$ in the 3 bins of $p_\mathrm{T}^\mathrm{t\bar{t}}$, and inclusively (bottom row). The value 9999 is used as a...

  • Table 27

    Data from Figure 2

    10.17182/hepdata.71444.v1/t27

    Statistical correlation matrix for $A^{\mathrm{lep}}_{\mathrm{C}}$ in the 3 bins of $p_\mathrm{T}^\mathrm{t\bar{t}}$.

  • Table 28

    Data from Figure 2

    10.17182/hepdata.71444.v1/t28

    Systematic correlation matrix for $A^{\mathrm{lep}}_{\mathrm{C}}$ in the 3 bins of $p_\mathrm{T}^\mathrm{t\bar{t}}$.

  • Table 29

    Data from Figure 2

    10.17182/hepdata.71444.v1/t29

    Fraction of events in each of the $12\times3$ bins of the normalized differential cross section as a function of $\Delta|\eta_{\ell}|$...

  • Table 30

    Data from Figure 2

    10.17182/hepdata.71444.v1/t30

    Statistical covariance matrix for the $12\times3$ bins of the normalized differential cross section as a function of $\Delta|\eta_{\ell}|$ and $p_\mathrm{T}^\mathrm{t\bar{t}}$.

  • Table 31

    Data from Figure 2

    10.17182/hepdata.71444.v1/t31

    Systematic covariance matrix for the $12\times3$ bins of the normalized differential cross section as a function of $\Delta|\eta_{\ell}|$ and $p_\mathrm{T}^\mathrm{t\bar{t}}$.

  • Table 32

    Data from Figure 2

    10.17182/hepdata.71444.v1/t32

    Values of $A_{\mathrm{C}}$ in the 3 bins of $|y_\mathrm{t\bar{t}}|$, and inclusively (bottom row). The value 9999 is used as a...

  • Table 33

    Data from Figure 2

    10.17182/hepdata.71444.v1/t33

    Statistical correlation matrix for $A_{\mathrm{C}}$ in the 3 bins of $|y_\mathrm{t\bar{t}}|$.

  • Table 34

    Data from Figure 2

    10.17182/hepdata.71444.v1/t34

    Systematic correlation matrix for $A_{\mathrm{C}}$ in the 3 bins of $|y_\mathrm{t\bar{t}}|$.

  • Table 35

    Data from Figure 2

    10.17182/hepdata.71444.v1/t35

    Fraction of events in each of the $6\times3$ bins of the normalized differential cross section as a function of $\Delta|y_\mathrm{t}|$...

  • Table 36

    Data from Figure 2

    10.17182/hepdata.71444.v1/t36

    Statistical covariance matrix for the $6\times3$ bins of the normalized differential cross section as a function of $\Delta|y_\mathrm{t}|$ and $|y_\mathrm{t\bar{t}}|$.

  • Table 37

    Data from Figure 2

    10.17182/hepdata.71444.v1/t37

    Systematic covariance matrix for the $6\times3$ bins of the normalized differential cross section as a function of $\Delta|y_\mathrm{t}|$ and $|y_\mathrm{t\bar{t}}|$.

  • Table 38

    Data from Figure 2

    10.17182/hepdata.71444.v1/t38

    Values of $A^{\mathrm{lep}}_{\mathrm{C}}$ in the 3 bins of $|y_\mathrm{t\bar{t}}|$, and inclusively (bottom row). The value 9999 is used as a...

  • Table 39

    Data from Figure 2

    10.17182/hepdata.71444.v1/t39

    Statistical correlation matrix for $A^{\mathrm{lep}}_{\mathrm{C}}$ in the 3 bins of $|y_\mathrm{t\bar{t}}|$.

  • Table 40

    Data from Figure 2

    10.17182/hepdata.71444.v1/t40

    Systematic correlation matrix for $A^{\mathrm{lep}}_{\mathrm{C}}$ in the 3 bins of $|y_\mathrm{t\bar{t}}|$.

  • Table 41

    Data from Figure 2

    10.17182/hepdata.71444.v1/t41

    Fraction of events in each of the $12\times3$ bins of the normalized differential cross section as a function of $\Delta|\eta_{\ell}|$...

  • Table 42

    Data from Figure 2

    10.17182/hepdata.71444.v1/t42

    Statistical covariance matrix for the $12\times3$ bins of the normalized differential cross section as a function of $\Delta|\eta_{\ell}|$ and $|y_\mathrm{t\bar{t}}|$.

  • Table 43

    Data from Figure 2

    10.17182/hepdata.71444.v1/t43

    Systematic covariance matrix for the $12\times3$ bins of the normalized differential cross section as a function of $\Delta|\eta_{\ell}|$ and $|y_\mathrm{t\bar{t}}|$.

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