{"@context":"http://schema.org","@id":"https://doi.org/10.17182/hepdata.157848.v2","@reverse":{"isBasedOn":[{"@type":"ScholarlyArticle","identifier":{"@type":"PropertyValue","propertyID":"URL","value":"https://inspirehep.net/literature/3076866"}},{"@id":"https://doi.org/10.1007/JHEP04(2026)086","@type":"JournalArticle"}]},"@type":"Dataset","additionalType":"Collection","author":{"@type":"Organization","name":"CMS Collaboration"},"creator":{"@type":"Organization","name":"CMS Collaboration"},"datePublished":"2026","description":"Inclusive and differential cross section measurements of top quark pair ($\\mathrm{t\\bar{t}}$) production in association with a photon ($\u03b3$) are performed as a function of lepton, photon, top quark, and $\\mathrm{t\\bar{t}}$ kinematic observables, using data from proton-proton collisions at $\\sqrt{s}$ = 13 TeV, corresponding to an integrated luminosity of 138 fb$^{-1}$, collected at the CERN LHC with the CMS detector. Events containing two leptons (electrons or muons) and a photon in the final state are considered. The fiducial cross section of $\\mathrm{t\\bar{t}}\u03b3$ is measured to be 137 $\\pm$ 8 fb, in a phase space including events with a high momentum, isolated photon. The fiducial cross section of $\\mathrm{t\\bar{t}}\u03b3$ is also measured to be 56 $\\pm$ 5 fb when considering only events where the photon is emitted in the production part of the process. Both measurements are in agreement with the theoretical predictions, of 126 $\\pm$ 19 fb and 57 $\\pm$ 5 fb, respectively. Differential measurements are performed at the particle and parton levels. Additionally, inclusive and differential ratios between the cross sections of $\\mathrm{t\\bar{t}}\u03b3$ and $\\mathrm{t\\bar{t}}$ production are measured. The inclusive ratio is found to be 0.0133 $\\pm$ 0.0005, in agreement with the standard model prediction of 0.0127 $\\pm$ 0.0008. The top quark charge asymmetry in $\\mathrm{t\\bar{t}}\u03b3$ production is also measured to be $-$0.012 $\\pm$ 0.042, compatible with both the standard model prediction and with no asymmetry.","hasPart":[{"@id":"https://doi.org/10.17182/hepdata.157848.v2/t1","@type":"Dataset","description":"Comparison between the observed and expected events after the event selection, for the $p_{\\mathrm{T}}$ of the photon.","name":"Figure 2a"},{"@id":"https://doi.org/10.17182/hepdata.157848.v2/t2","@type":"Dataset","description":"Comparison between the observed and expected events after the event selection, for the $p_{\\mathrm{T}}$ of the leading lepton.","name":"Figure 2b"},{"@id":"https://doi.org/10.17182/hepdata.157848.v2/t3","@type":"Dataset","description":"Comparison between the observed and expected events after the event selection, for the number of jets.","name":"Figure 2c"},{"@id":"https://doi.org/10.17182/hepdata.157848.v2/t4","@type":"Dataset","description":"Comparison between the observed and expected events after the event selection, for the minimum $\\Delta R (\\gamma,\\ell)$.","name":"Figure 2d"},{"@id":"https://doi.org/10.17182/hepdata.157848.v2/t5","@type":"Dataset","description":"Absolute differential distributions of the leading top quark $p_{\\mathrm{T}}$. The nominal MC prediction used to compare the experimental results to...","name":"Figure 7a"},{"@id":"https://doi.org/10.17182/hepdata.157848.v2/t6","@type":"Dataset","description":"Normalized differential distributions of the leading top quark $p_{\\mathrm{T}}$. The nominal MC prediction used to compare the experimental results to...","name":"Figure 7b"},{"@id":"https://doi.org/10.17182/hepdata.157848.v2/t7","@type":"Dataset","description":"Absolute differential distributions of the $\\Delta R (\\gamma,\\mathrm{tt})$. The nominal MC prediction used to compare the experimental results to is...","name":"Figure 7c"},{"@id":"https://doi.org/10.17182/hepdata.157848.v2/t8","@type":"Dataset","description":"Normalized differential distributions of the $\\Delta R (\\gamma,\\mathrm{tt})$. The nominal MC prediction used to compare the experimental results to is...","name":"Figure 7d"},{"@id":"https://doi.org/10.17182/hepdata.157848.v2/t9","@type":"Dataset","description":"Absolute differential distributions of the min. $\\Delta R (\\gamma,\\mathrm{t})$. The nominal MC prediction used to compare the experimental results to...","name":"Figure 8a"},{"@id":"https://doi.org/10.17182/hepdata.157848.v2/t10","@type":"Dataset","description":"Normalized differential distributions of the min. $\\Delta R (\\gamma,\\mathrm{t})$. The nominal MC prediction used to compare the experimental results to...","name":"Figure 8b"},{"@id":"https://doi.org/10.17182/hepdata.157848.v2/t11","@type":"Dataset","description":"Absolute differential distributions of the $m(\\mathrm{tt})$. The nominal MC prediction used to compare the experimental results to is obtained with...","name":"Figure 8c"},{"@id":"https://doi.org/10.17182/hepdata.157848.v2/t12","@type":"Dataset","description":"Normalized differential distributions of the $m(\\mathrm{tt})$. The nominal MC prediction used to compare the experimental results to is obtained with...","name":"Figure 8d"},{"@id":"https://doi.org/10.17182/hepdata.157848.v2/t13","@type":"Dataset","description":"Absolute differential distributions of the leading lepton $p_{\\mathrm{T}}$. The nominal MC prediction used to compare the experimental results to is...","name":"Figure 9a"},{"@id":"https://doi.org/10.17182/hepdata.157848.v2/t14","@type":"Dataset","description":"Normalized differential distributions of the leading lepton $p_{\\mathrm{T}}$. The nominal MC prediction used to compare the experimental results to is...","name":"Figure 9b"},{"@id":"https://doi.org/10.17182/hepdata.157848.v2/t15","@type":"Dataset","description":"Absolute differential distributions of the photon $p_{\\mathrm{T}}$. The nominal MC prediction used to compare the experimental results to is obtained...","name":"Figure 9c"},{"@id":"https://doi.org/10.17182/hepdata.157848.v2/t16","@type":"Dataset","description":"Normalized differential distributions of the photon $p_{\\mathrm{T}}$. The nominal MC prediction used to compare the experimental results to is obtained...","name":"Figure 9d"},{"@id":"https://doi.org/10.17182/hepdata.157848.v2/t17","@type":"Dataset","description":"Absolute differential distributions of the $\\Delta \\phi (\\ell,\\ell)$. The nominal MC prediction used to compare the experimental results to is...","name":"Figure 10a"},{"@id":"https://doi.org/10.17182/hepdata.157848.v2/t18","@type":"Dataset","description":"Normalized differential distributions of the $\\Delta \\phi (\\ell,\\ell)$. 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