CMS-TOP-16-007 ; CERN-EP-2017-120 | ||
Measurement of normalized differential $\mathrm{ t \bar{t} }$ cross sections in the dilepton channel from pp collisions at $ \sqrt{s} = $ 13 TeV | ||
CMS Collaboration | ||
25 August 2017 | ||
JHEP 04 (2018) 060 | ||
Abstract: Normalized differential cross sections for top quark pair production are measured in the dilepton ($\mathrm{ e }^{+}\mathrm{ e }^{-}$, $\mu^{+}\mu^{-}$, and $\mu^{\mp}\mathrm{ e }^{\pm}$) decay channels in proton-proton collisions at a center-of-mass energy of 13 TeV. The measurements are performed with data corresponding to an integrated luminosity of 2.1 fb$^{-1}$ using the CMS detector at the LHC. The cross sections are measured differentially as a function of the kinematic properties of the leptons, jets from bottom quark hadronization, top quarks, and top quark pairs at the particle and parton levels. The results are compared to several Monte Carlo generators that implement calculations up to next-to-leading order in perturbative quantum chromodynamics interfaced with parton showering, and also to fixed-order theoretical calculations of top quark pair production up to next-to-next-to-leading order. | ||
Links: e-print arXiv:1708.07638 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; HepData record ; CADI line (restricted) ; |
Figures | |
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Figure 1:
Reconstructed $ { {p_{\mathrm {T}}} ^{{ \rm lep}}} $ (upper left), $ { {p_{\mathrm {T}}} ^{{ \rm jet}}} $ (upper right), $ { {p_{\mathrm {T}}} ^{\rm t}} $ (lower left), and $ {y^{\rm t}} $ (lower right) distributions from data (points) and from MC simulation (shaded histograms). The signal definition for particle level is considered to distinguish $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-signal and $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-others. All corrections described in the text are applied to the simulation. The last bin includes the overflow events. The uncertainties shown by the vertical bars on the data points are statistical only while the hatched band shows the combined statistical and systematic uncertainties added in quadrature. The lower panels display the ratios of the data to the MC prediction. |
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Figure 1-a:
Reconstructed $ { {p_{\mathrm {T}}} ^{{ \rm lep}}} $ distribution from data (points) and from MC simulation (shaded histograms). The signal definition for particle level is considered to distinguish $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-signal and $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-others. All corrections described in the text are applied to the simulation. The last bin includes the overflow events. The uncertainties shown by the vertical bars on the data points are statistical only while the hatched band shows the combined statistical and systematic uncertainties added in quadrature. The lower panel displays the ratios of the data to the MC prediction. |
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Figure 1-b:
Reconstructed $ { {p_{\mathrm {T}}} ^{{ \rm jet}}} $ distribution from data (points) and from MC simulation (shaded histograms). The signal definition for particle level is considered to distinguish $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-signal and $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-others. All corrections described in the text are applied to the simulation. The last bin includes the overflow events. The uncertainties shown by the vertical bars on the data points are statistical only while the hatched band shows the combined statistical and systematic uncertainties added in quadrature. The lower panel displays the ratios of the data to the MC prediction. |
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Figure 1-c:
Reconstructed $ { {p_{\mathrm {T}}} ^{\rm t}} $ distribution from data (points) and from MC simulation (shaded histograms). The signal definition for particle level is considered to distinguish $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-signal and $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-others. All corrections described in the text are applied to the simulation. The last bin includes the overflow events. The uncertainties shown by the vertical bars on the data points are statistical only while the hatched band shows the combined statistical and systematic uncertainties added in quadrature. The lower panel displays the ratios of the data to the MC prediction. |
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Figure 1-d:
Reconstructed $ {y^{\rm t}} $ distribution from data (points) and from MC simulation (shaded histograms). The signal definition for particle level is considered to distinguish $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-signal and $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-others. All corrections described in the text are applied to the simulation. The last bin includes the overflow events. The uncertainties shown by the vertical bars on the data points are statistical only while the hatched band shows the combined statistical and systematic uncertainties added in quadrature. The lower panel displays the ratios of the data to the MC prediction. |
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Figure 2:
Reconstructed $ {p_{\mathrm {T}}^{{{\mathrm{ t } {}\mathrm{ \bar{t} } } }}} $ (upper left), $ {y^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $ (upper right), $ {M^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $ (lower left), and $ {\Delta \phi ^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $ (lower right) distributions from data (points) and from MC simulation (shaded histograms). The signal definition for particle level is considered to distinguish $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-signal and $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-others. All corrections described in the text are applied to the simulation. The last bin includes the overflow events. The uncertainties shown by the vertical bars on the data points are statistical only only while the hatched band shows the combined statistical and systematic uncertainties added in quadrature. The lower panels display the ratios of the data to the MC prediction. |
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Figure 2-a:
Reconstructed $ {p_{\mathrm {T}}^{{{\mathrm{ t } {}\mathrm{ \bar{t} } } }}} $ distribution from data (points) and from MC simulation (shaded histograms). The signal definition for particle level is considered to distinguish $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-signal and $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-others. All corrections described in the text are applied to the simulation. The last bin includes the overflow events. The uncertainties shown by the vertical bars on the data points are statistical only only while the hatched band shows the combined statistical and systematic uncertainties added in quadrature. The lower panel displays the ratios of the data to the MC prediction. |
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Figure 2-b:
Reconstructed $ {y^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $ distribution from data (points) and from MC simulation (shaded histograms). The signal definition for particle level is considered to distinguish $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-signal and $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-others. All corrections described in the text are applied to the simulation. The last bin includes the overflow events. The uncertainties shown by the vertical bars on the data points are statistical only only while the hatched band shows the combined statistical and systematic uncertainties added in quadrature. The lower panel displays the ratios of the data to the MC prediction. |
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Figure 2-c:
Reconstructed $ {M^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $ distribution from data (points) and from MC simulation (shaded histograms). The signal definition for particle level is considered to distinguish $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-signal and $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-others. All corrections described in the text are applied to the simulation. The last bin includes the overflow events. The uncertainties shown by the vertical bars on the data points are statistical only only while the hatched band shows the combined statistical and systematic uncertainties added in quadrature. The lower panel displays the ratios of the data to the MC prediction. |
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Figure 2-d:
Reconstructed $ {\Delta \phi ^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $ distribution from data (points) and from MC simulation (shaded histograms). The signal definition for particle level is considered to distinguish $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-signal and $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $-others. All corrections described in the text are applied to the simulation. The last bin includes the overflow events. The uncertainties shown by the vertical bars on the data points are statistical only only while the hatched band shows the combined statistical and systematic uncertainties added in quadrature. The lower panel displays the ratios of the data to the MC prediction. |
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Figure 3:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of lepton (upper left), jet (upper right), and top quark $ {p_{\mathrm {T}}} $ (lower left) and top quark rapidity (lower right), measured at the particle level in the visible phase space and combining the distributions for top quarks and antiquarks. The measured data are compared to different standard model predictions from POWHEG+PYTHIA 8 (POWHEG P8), MG5_aMC@NLO+PYTHIA 8[MLM] (MG5 P8 [MLM]), MG5_aMC@NLO+PYTHIA 8[FXFX] (MG5 P8 [FXFX]), and POWHEG+HERWIG++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. |
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Figure 3-a:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of lepton $ {p_{\mathrm {T}}} $, measured at the particle level in the visible phase space and combining the distributions for top quarks and antiquarks. The measured data are compared to different standard model predictions from POWHEG+PYTHIA 8 (POWHEG P8), MG5_aMC@NLO+PYTHIA 8[MLM] (MG5 P8 [MLM]), MG5_aMC@NLO+PYTHIA 8[FXFX] (MG5 P8 [FXFX]), and POWHEG+HERWIG++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. |
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Figure 3-b:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of jet $ {p_{\mathrm {T}}} $, measured at the particle level in the visible phase space and combining the distributions for top quarks and antiquarks. The measured data are compared to different standard model predictions from POWHEG+PYTHIA 8 (POWHEG P8), MG5_aMC@NLO+PYTHIA 8[MLM] (MG5 P8 [MLM]), MG5_aMC@NLO+PYTHIA 8[FXFX] (MG5 P8 [FXFX]), and POWHEG+HERWIG++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. |
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Figure 3-c:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of top quark $ {p_{\mathrm {T}}} $, measured at the particle level in the visible phase space and combining the distributions for top quarks and antiquarks. The measured data are compared to different standard model predictions from POWHEG+PYTHIA 8 (POWHEG P8), MG5_aMC@NLO+PYTHIA 8[MLM] (MG5 P8 [MLM]), MG5_aMC@NLO+PYTHIA 8[FXFX] (MG5 P8 [FXFX]), and POWHEG+HERWIG++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. |
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Figure 3-d:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of top quark $ rapidity, measured at the particle level in the visible phase space and combining the distributions for top quarks and antiquarks. The measured data are compared to different standard model predictions from POWHEG+PYTHIA 8 (POWHEG P8), MG5_aMC@NLO+PYTHIA 8[MLM] (MG5 P8 [MLM]), MG5_aMC@NLO+PYTHIA 8[FXFX] (MG5 P8 [FXFX]), and POWHEG+HERWIG++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. |
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Figure 4:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of $ {p_{\mathrm {T}}^{{{\mathrm{ t } {}\mathrm{ \bar{t} } } }}} $ (upper left), $ {y^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $ (upper right), $ {M^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $ (lower left), and $ {\Delta \phi ^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $ (lower right), measured at the particle level in the visible phase space. The measured data are compared to different standard model predictions from POWHEG+PYTHIA 8 (POWHEG P8), MG5_aMC@NLO+PYTHIA 8[MLM] (MG5 P8 [MLM]), MG5_aMC@NLO+PYTHIA 8[FXFX] (MG5 P8 [FXFX]), and POWHEG+HERWIG++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. |
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Figure 4-a:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of $ {p_{\mathrm {T}}^{{{\mathrm{ t } {}\mathrm{ \bar{t} } } }}} $, measured at the particle level in the visible phase space. The measured data are compared to different standard model predictions from POWHEG+PYTHIA 8 (POWHEG P8), MG5_aMC@NLO+PYTHIA 8[MLM] (MG5 P8 [MLM]), MG5_aMC@NLO+PYTHIA 8[FXFX] (MG5 P8 [FXFX]), and POWHEG+HERWIG++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. |
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Figure 4-b:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of $ {y^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $, measured at the particle level in the visible phase space. The measured data are compared to different standard model predictions from POWHEG+PYTHIA 8 (POWHEG P8), MG5_aMC@NLO+PYTHIA 8[MLM] (MG5 P8 [MLM]), MG5_aMC@NLO+PYTHIA 8[FXFX] (MG5 P8 [FXFX]), and POWHEG+HERWIG++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. |
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Figure 4-c:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of $ {M^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $, measured at the particle level in the visible phase space. The measured data are compared to different standard model predictions from POWHEG+PYTHIA 8 (POWHEG P8), MG5_aMC@NLO+PYTHIA 8[MLM] (MG5 P8 [MLM]), MG5_aMC@NLO+PYTHIA 8[FXFX] (MG5 P8 [FXFX]), and POWHEG+HERWIG++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. |
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Figure 4-d:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of $ {\Delta \phi ^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $, measured at the particle level in the visible phase space. The measured data are compared to different standard model predictions from POWHEG+PYTHIA 8 (POWHEG P8), MG5_aMC@NLO+PYTHIA 8[MLM] (MG5 P8 [MLM]), MG5_aMC@NLO+PYTHIA 8[FXFX] (MG5 P8 [FXFX]), and POWHEG+HERWIG++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. |
png pdf |
Figure 5:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of top quark $ {p_{\mathrm {T}}} $ (left) and top quark rapidity (right), measured at the parton level in the full phase space and combining the distributions for top quarks and antiquarks. The measured data are compared to different standard model predictions from POWHEG+PYTHIA 8 (POWHEG P8), MG5_aMC@NLO+PYTHIA 8[MLM] (MG5 P8 [MLM]), MG5_aMC@NLO+PYTHIA 8[FXFX] (MG5 P8 [FXFX]), and POWHEG+HERWIG++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. |
png pdf |
Figure 5-a:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of top quark $ {p_{\mathrm {T}}} $, measured at the parton level in the full phase space and combining the distributions for top quarks and antiquarks. The measured data are compared to different standard model predictions from POWHEG+PYTHIA 8 (POWHEG P8), MG5_aMC@NLO+PYTHIA 8[MLM] (MG5 P8 [MLM]), MG5_aMC@NLO+PYTHIA 8[FXFX] (MG5 P8 [FXFX]), and POWHEG+HERWIG++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. |
png pdf |
Figure 5-b:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of top quark rapidity, measured at the parton level in the full phase space and combining the distributions for top quarks and antiquarks. The measured data are compared to different standard model predictions from POWHEG+PYTHIA 8 (POWHEG P8), MG5_aMC@NLO+PYTHIA 8[MLM] (MG5 P8 [MLM]), MG5_aMC@NLO+PYTHIA 8[FXFX] (MG5 P8 [FXFX]), and POWHEG+HERWIG++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. |
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Figure 6:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of $ {p_{\mathrm {T}}^{{{\mathrm{ t } {}\mathrm{ \bar{t} } } }}} $ (upper left), $ {y^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $ (upper right), $ {M^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $ (lower left), and $ {\Delta \phi ^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $ (lower right), measured at the parton level in the full phase space. The measured data are compared to different standard model predictions from POWHEG+PYTHIA 8 (POWHEG P8), MG5_aMC@NLO+PYTHIA 8[MLM] (MG5 P8 [MLM]), MG5_aMC@NLO+PYTHIA 8[FXFX] (MG5 P8 [FXFX]), and POWHEG+HERWIG++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. |
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Figure 6-a:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of $ {p_{\mathrm {T}}^{{{\mathrm{ t } {}\mathrm{ \bar{t} } } }}} $, measured at the parton level in the full phase space. The measured data are compared to different standard model predictions from POWHEG+PYTHIA 8 (POWHEG P8), MG5_aMC@NLO+PYTHIA 8[MLM] (MG5 P8 [MLM]), MG5_aMC@NLO+PYTHIA 8[FXFX] (MG5 P8 [FXFX]), and POWHEG+HERWIG++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. |
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Figure 6-b:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of $ {y^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $, measured at the parton level in the full phase space. The measured data are compared to different standard model predictions from POWHEG+PYTHIA 8 (POWHEG P8), MG5_aMC@NLO+PYTHIA 8[MLM] (MG5 P8 [MLM]), MG5_aMC@NLO+PYTHIA 8[FXFX] (MG5 P8 [FXFX]), and POWHEG+HERWIG++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. |
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Figure 6-c:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of $ {M^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $, measured at the parton level in the full phase space. The measured data are compared to different standard model predictions from POWHEG+PYTHIA 8 (POWHEG P8), MG5_aMC@NLO+PYTHIA 8[MLM] (MG5 P8 [MLM]), MG5_aMC@NLO+PYTHIA 8[FXFX] (MG5 P8 [FXFX]), and POWHEG+HERWIG++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. |
png pdf |
Figure 6-d:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of $ {\Delta \phi ^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $, measured at the parton level in the full phase space. The measured data are compared to different standard model predictions from POWHEG+PYTHIA 8 (POWHEG P8), MG5_aMC@NLO+PYTHIA 8[MLM] (MG5 P8 [MLM]), MG5_aMC@NLO+PYTHIA 8[FXFX] (MG5 P8 [FXFX]), and POWHEG+HERWIG++ (POWHEG H++). The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties while the hatched band shows the statistical uncertainty. The lower panel gives the ratio of the theoretical predictions to the data. The light-shaded band displays the combined statistical and systematic uncertainties added in quadrature. |
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Figure 7:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of top quark $ {p_{\mathrm {T}}} $ (left) and top quark rapidity (right), measured at the parton level in the full phase space and combining the distributions for top quarks and antiquarks. The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties, while the hatched band shows the statistical uncertainty. The measurements are compared to different perturbative QCD calculations of an approximate NNLO [59], an approximate next-to-NNLO (N$^{3}$LO) [60], an improved NLO+NNLL (NLO+NNLL') [62], and a full NNLO [63]. The lower panel gives the ratio of the theoretical predictions to the data. |
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Figure 7-a:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of top quark $ {p_{\mathrm {T}}} $, measured at the parton level in the full phase space and combining the distributions for top quarks and antiquarks. The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties, while the hatched band shows the statistical uncertainty. The measurements are compared to different perturbative QCD calculations of an approximate NNLO [59], an approximate next-to-NNLO (N$^{3}$LO) [60], an improved NLO+NNLL (NLO+NNLL') [62], and a full NNLO [63]. The lower panel gives the ratio of the theoretical predictions to the data. |
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Figure 7-b:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of top quark rapidity, measured at the parton level in the full phase space and combining the distributions for top quarks and antiquarks. The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties, while the hatched band shows the statistical uncertainty. The measurements are compared to different perturbative QCD calculations of an approximate NNLO [59], an approximate next-to-NNLO (N$^{3}$LO) [60], an improved NLO+NNLL (NLO+NNLL') [62], and a full NNLO [63]. The lower panel gives the ratio of the theoretical predictions to the data. |
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Figure 8:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of $ {p_{\mathrm {T}}^{{{\mathrm{ t } {}\mathrm{ \bar{t} } } }}} $ (upper left), $ {y^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $ (upper right), and $ {M^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $ (lower) for the top quarks or antiquarks, measured at parton level in the full phase space. The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties, while the hatched band shows the statistical uncertainty. The measurements are compared to different perturbative QCD calculations of an improved NLO+NNLL (NLO+NNLL') [62] and a full NNLO [63]. The lower panel gives the ratio of the theoretical predictions to the data. |
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Figure 8-a:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of $ {p_{\mathrm {T}}^{{{\mathrm{ t } {}\mathrm{ \bar{t} } } }}} $ for the top quarks or antiquarks, measured at parton level in the full phase space. The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties, while the hatched band shows the statistical uncertainty. The measurements are compared to different perturbative QCD calculations of an improved NLO+NNLL (NLO+NNLL') [62] and a full NNLO [63]. The lower panel gives the ratio of the theoretical predictions to the data. |
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Figure 8-b:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of $ {y^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $ for the top quarks or antiquarks, measured at parton level in the full phase space. The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties, while the hatched band shows the statistical uncertainty. The measurements are compared to different perturbative QCD calculations of an improved NLO+NNLL (NLO+NNLL') [62] and a full NNLO [63]. The lower panel gives the ratio of the theoretical predictions to the data. |
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Figure 8-c:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections as a function of $ {M^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $ for the top quarks or antiquarks, measured at parton level in the full phase space. The vertical bars on the data points indicate the total (combined statistical and systematic) uncertainties, while the hatched band shows the statistical uncertainty. The measurements are compared to different perturbative QCD calculations of an improved NLO+NNLL (NLO+NNLL') [62] and a full NNLO [63]. The lower panel gives the ratio of the theoretical predictions to the data. |
Tables | |
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Table 1:
Summary of the object definitions at the particle level. |
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Table 2:
Statistical and systematic uncertainties in the normalized $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ differential cross sections at particle and parton levels. The uncertainty sources and the corresponding range of the median uncertainty of each distribution are shown in percent. |
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Table 3:
The $\chi ^{2}/$dof and $\rm p$-values for the comparison of the measured normalized $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ differential cross sections with different model predictions at the particle level for each of the kinematic variables. |
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Table 4:
The $\chi ^{2}/$dof and $\rm p$-values for the comparison of the measured normalized $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ differential cross sections with different model predictions at the parton level for each of the kinematic variables. |
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Table 5:
The $\chi ^{2}/$dof and $\rm p$-values for the comparison of the measured normalized $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ differential cross sections with published perturbative QCD calculations. |
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Table 6:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections with statistical and systematic uncertainties at the particle level as a function of $ { {p_{\mathrm {T}}} ^{{ \rm lep}}} $. The factor given in the last column applies to the values of the normalized cross section and the statistical and systematic uncertainties in that row. |
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Table 7:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections with statistical and systematic uncertainties at the particle level as a function of $ { {p_{\mathrm {T}}} ^{{ \rm jet}}} $. The factor given in the last column applies to the values of the normalized cross section and the statistical and systematic uncertainties in that row. |
png pdf |
Table 8:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections with statistical and systematic uncertainties at the particle level as a function of $ { {p_{\mathrm {T}}} ^{\rm t}} $. The factor given in the last column applies to the values of the normalized cross section and the statistical and systematic uncertainties in that row. |
png pdf |
Table 9:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections with statistical and systematic uncertainties at the particle level as a function of $ {y^{\rm t}} $. The factor given in the last column applies to the values of the normalized cross section and the statistical and systematic uncertainties in that row. |
png pdf |
Table 10:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections with statistical and systematic uncertainties at the particle level as a function of $p_{\rm T}^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }$. The factor given in the last column applies to the values of the normalized cross section and the statistical and systematic uncertainties in that row. |
png pdf |
Table 11:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections with statistical and systematic uncertainties at the particle level as a function of $ {y^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $. The factor given in the last column applies to the values of the normalized cross section and the statistical and systematic uncertainties in that row. |
png pdf |
Table 12:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections with statistical and systematic uncertainties at the particle level as a function of $ {M^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $. The factor given in the last column applies to the values of the normalized cross section and the statistical and systematic uncertainties in that row. |
png pdf |
Table 13:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections with statistical and systematic uncertainties at the particle level as a function of $ {\Delta \phi ^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $. The factor given in the last column applies to the values of the normalized cross section and the statistical and systematic uncertainties in that row. |
png pdf |
Table 14:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections with statistical and systematic uncertainties at the parton level as a function of $p_{\rm T}^{\rm t}$. The factor given in the last column applies to the values of the normalized cross section and the statistical and systematic uncertainties in that row. |
png pdf |
Table 15:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections with statistical and systematic uncertainties at the parton level as a function of $ {y^{\rm t}} $. The factor given in the last column applies to the values of the normalized cross section and the statistical and systematic uncertainties in that row. |
png pdf |
Table 16:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections with statistical and systematic uncertainties at the parton level as a function of $p_{\rm T}^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }$. The factor given in the last column applies to the values of the normalized cross section and the statistical and systematic uncertainties in that row. |
png pdf |
Table 17:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections with statistical and systematic uncertainties at the parton level as a function of $ {y^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $. The factor given in the last column applies to the values of the normalized cross section and the statistical and systematic uncertainties in that row. |
png pdf |
Table 18:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections with statistical and systematic uncertainties at the parton level as a function of $ {M^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $. The factor given in the last column applies to the values of the normalized cross section and the statistical and systematic uncertainties in that row. |
png pdf |
Table 19:
Normalized differential $ {\mathrm{ t } {}\mathrm{ \bar{t} } } $ cross sections with statistical and systematic uncertainties at the parton level as a function of $ {\Delta \phi ^{{\mathrm{ t } {}\mathrm{ \bar{t} } } }} $. The factor given in the last column applies to the values of the normalized cross section and the statistical and systematic uncertainties in that row. |
Summary |
The normalized differential cross sections for top quark pair production have been presented by the CMS experiment in the dilepton decay channel in pp collisions at $ \sqrt{s} = $ 13 TeV with data corresponding to an integrated luminosity of 2.1 fb$^{-1}$. The differential cross sections are measured as a function of several kinematic variables at particle level in a visible phase space corresponding to the detector acceptance and at parton level in the full phase space. The measurements are compared to the predictions from Monte Carlo simulations and calculations in perturbative quantum chromodynamics. In general, the measurements are in fairly good agreement with predictions. We confirm that the top quark $ p_{\mathrm{T}} $ spectrum in data is softer than the Monte Carlo predictions at both particle and parton levels, as reported by the ATLAS and CMS experiments. The present results are in agreement with the earlier ATLAS and CMS measurements. We also find that the measurements are in better agreement with calculations within quantum chromodynamics up to next-to-next-to-leading-order accuracy at the parton level compared to previous next-to-leading-order predictions. |
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Compact Muon Solenoid LHC, CERN |