Date

Observation of coherent $\phi$(1020) meson photoproduction in ultraperipheral PbPb collisions at $\sqrt{s_\text{NN}}$ = 5.36 TeV

The CMS collaboration Chekhovsky, Vladimir ; Hayrapetyan, Aram ; Makarenko, Vladimir ; et al.
CMS-HIN-24-009, 2025.
Inspire Record 2908607 DOI 10.17182/hepdata.156183

The first observation of coherent $\phi$(1020) meson photoproduction off heavy nuclei is presented using ultraperipheral lead-lead collisions at a center-of-mass energy per nucleon pair of 5.36 TeV. The data were collected by the CMS experiment and correspond to an integrated luminosity of 1.68 $\mu$b$^{-1}$. The $\phi$(1020) meson signals are reconstructed via the K$^+$K$^-$ decay channel. The production cross section is presented as a function of the $\phi$(1020) meson rapidity in the range 0.3 $\lt$$\lvert y\rvert$$\lt$ 1.0, probing gluons that carry a fraction of the nucleon momentum ($x$) around $10^{-4}$. The observed cross section exhibits little dependence on rapidity and is significantly suppressed, by a factor of ${\sim}$5, compared to a baseline model that treats a nucleus as a collection of free nucleons. Theoretical models that incorporate either nuclear shadowing or gluon saturation predict suppression of the $\phi$(1020) meson cross section with only a small dependence on rapidity, but the magnitude of the predicted suppression varies greatly. Models considering only nuclear shadowing effects result in the best agreement with the experimental data. This study establishes a powerful new tool for exploring nuclear effects and nuclear gluonic structure in the small-$x$ regime at a unique energy scale bridging the perturbative and nonperturbative quantum chromodynamics domains.

1 data table

The differential coherent $\phi$ photoproduction cross section and the nuclear suppression factor as a function of rapidity.


Measurement of the inclusive $\mathrm{t\bar{t}}$ cross section in final states with at least one lepton and additional jets with 302 pb$^{-1}$ of pp collisions at $\sqrt{s}$ = 5.0 TeV

The CMS collaboration Hayrapetyan, Aram ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
JHEP 04 (2025) 099, 2025.
Inspire Record 2844500 DOI 10.17182/hepdata.150676

A measurement of the top quark pair ($\mathrm{t\bar{t}}$) production cross section in proton-proton collisions at a centre-of-mass energy of 5.02 TeV is presented. The data were collected at the LHC in autumn 2017, in dedicated runs with low-energy and low-intensity conditions with respect to the default configuration, and correspond to an integrated luminosity of 302 pb$^{-1}$. The measurement is performed using events with one electron or muon, and multiple jets, at least one of them being identified as b quark (b tagged). Events are classified based on the number of all reconstructed jets and of b-tagged jets. Multivariate analysis techniques are used to enhance the separation between the signal and backgrounds. The measured cross section is 62.5 $\pm$ 1.6 (stat) $^{+2.6}_{-2.5}$ (syst) $\pm$ 1.2 (lumi) pb. A combination with the result in the dilepton channel based on the same data set yields a value of 62.3 $\pm$ 1.5 (stat) $\pm$ 2.4 (syst) $\pm$ 1.2 (lumi) pb, to be compared with the standard model prediction of 69.5$^{+3.5}_{-3.7}$ pb at next-to-next-to-leading order in perturbative quantum chromodynamics.

11 data tables

Distributions for data and expected signal and background contributions of the most discriminating input variables (\ensuremath{\Delta R_\mathrm{med}(\mathrm{j,j')}}) used for the random forest training, in the 3j1b category, before the maximum likelihood fit. The vertical error bars represent the statistical uncertainty in the data, and the shaded band the uncertainty in the prediction. All uncertainties considered in the analysis are included in the uncertainty band. The lower panels show the data-to-prediction ratio. The first and last bins in each distribution include underflow and overflow events, respectively.

Distributions for data and expected signal and background contributions of the most discriminating input variables (\ensuremath{\mathit{m}(\mathrm{u},\mathrm{u'})}) used for the random forest training, in the 3j1b category, before the maximum likelihood fit. The vertical error bars represent the statistical uncertainty in the data, and the shaded band the uncertainty in the prediction. All uncertainties considered in the analysis are included in the uncertainty band. The lower panels show the data-to-prediction ratio. The first and last bins in each distribution include underflow and overflow events, respectively.

Distributions for data and expected signal and background contributions of the MVA score for the e + jets channel in the 3j1b category, before the maximum likelihood fit. The vertical error bars represent the statistical uncertainty in the data, and the shaded band the uncertainty in the prediction. All uncertainties considered in the analysis are included in the uncertainty band. The lower panels show the data-to-prediction ratio. The first and last bins in each distribution include underflow and overflow events, respectively.

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Search for pair production of heavy particles decaying to a top quark and a gluon in the lepton+jets final state in proton-proton collisions at $\sqrt{s}$ = 13 TeV

The CMS collaboration Hayrapetyan, Aram ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
Eur.Phys.J.C 85 (2025) 342, 2025.
Inspire Record 2844507 DOI 10.17182/hepdata.155498

A search is presented for the pair production of new heavy resonances, each decaying into a top quark (t) or antiquark and a gluon (g). The analysis uses data recorded with the CMS detector from proton-proton collisions at a center-of-mass energy of 13 TeV at the LHC, corresponding to an integrated luminosity of 138 fb$^{-1}$. Events with one muon or electron, multiple jets, and missing transverse momentum are selected. After using a deep neural network to enrich the data sample with signal-like events, distributions in the scalar sum of the transverse momenta of all reconstructed objects are analyzed in the search for a signal. No significant deviations from the standard model prediction are found. Upper limits at 95% confidence level are set on the product of cross section and branching fraction squared for the pair production of excited top quarks in the $\mathrm{t^*}$ $\to$ tg decay channel. The upper limits range from 120 to 0.8 fb for a $\mathrm{t^*}$ with spin-1/2 and from 15 to 1.0 fb for a $\mathrm{t^*}$ with spin-3/2. These correspond to mass exclusion limits up to 1050 and 1700 GeV for spin-1/2 and spin-3/2 $\mathrm{t^*}$ particles, respectively. These are the most stringent limits to date on the existence of $\mathrm{t^*}$ $\to$ tg resonances.

4 data tables

Expected and observed 95% CL upper limits on the product of the $t^{*} \overline{t}^{*}$ production cross section and the branching fraction squared $BR^2(t^{*} \rightarrow tg)$ for a spin-1/2 $t^{*}$ as a function of $m_{t^{*}}$. The inner (green) and outer (yellow) bands give the central probability intervals containing 68 and 95% of the expected upper limits under the background-only hypothesis. The cross section predicted by theory, following an EFT approach, is shown in blue, assuming $BR(t^{*} \rightarrow tg)=1$.

Expected and observed 95% CL upper limits on the product of the $t^{*} \overline{t}^{*}$ production cross section and the branching fraction squared $BR^2(t^{*} \rightarrow tg)$ for a spin-3/2 $t^{*}$ as a function of $m_{t^{*}}$. The inner (green) and outer (yellow) bands give the central probability intervals containing 68 and 95% of the expected upper limits under the background-only hypothesis. The cross section predicted by theory, following an EFT approach, is shown in blue, assuming $BR(t^{*} \rightarrow tg)=1$. The results of the previous CMS analysis, using data corresponding to an integrated luminosity of 35.9 $fb^{-1}$, are shown in red.

Distributions in $S_T$ in the SR for the muon channel, after a background-only fit to the data. The signal distributions are scaled to the cross section predicted by the theory. The hatched bands show the post-fit uncertainty band, combining all sources of uncertainty. The ratio of data to the background predictions is shown in the panels below the distributions.

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Measurement of the $\mathrm{t\bar{t}}$H and tH production rates in the H $\to$$\mathrm{b\bar{b}}$ decay channel using proton-proton collision data at $\sqrt{s}$ = 13 TeV

The CMS collaboration Hayrapetyan, Aram ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
JHEP 02 (2025) 097, 2025.
Inspire Record 2808025 DOI 10.17182/hepdata.152799

An analysis of the production of a Higgs boson ($H$) in association with a top quark-antiquark pair ($\mathrm{t\bar{t}}H$) or a single top quark ($tH$) is presented. The Higgs boson decay into a bottom quark-antiquark pair ($H \to\mathrm{b\bar{b}}$) is targeted, and three different final states of the top quark decays are considered, defined by the number of leptons (electrons or muons) in the event. The analysis utilises proton-proton collision data collected at the CERN LHC with the CMS experiment at $\sqrt{s}$ = 13 TeV in 2016-2018, which correspond to an integrated luminosity of 138 fb$^{-1}$. The observed $\mathrm{t\bar{t}}H$ production rate relative to the standard model expectation is 0.33 $\pm$ 0.26 = 0.33 $\pm$ 0.17 (stat) $\pm$ 0.21 (syst). Additionally, the $\mathrm{t\bar{t}}H$ production rate is determined in intervals of Higgs boson transverse momentum. An upper limit at 95% confidence level is set on the tH production rate of 14.6 times the standard model prediction, with an expectation of 19.3 $^{+9.2}_{-6.0}$. Finally, constraints are derived on the strength and structure of the coupling between the Higgs boson and the top quark from simultaneous extraction of the $\mathrm{t\bar{t}}H$ and $tH$ production rates, and the results are combined with those obtained in other Higgs boson decay channels.

14 data tables

Best fit results of the ttH signal-strength modifier in each channel, in each year, and in the combination of all channels and years. Uncertainties are correlated between the channels and years.

Likelihood-ratio test statistic as a function of the ttH strength modifiers $\mu_{ttH}$ and the $ttB$ background normalisation. The observed best fit point is $(\mu_{ttH}, ttB) = (0.33, 1.19)$.

Best fit results of the ttH signal-strength modifiers in the different Higgs pT bins of the STXS measurement.

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Version 2
Measurement of inclusive and differential cross sections for W$^+$W$^-$ production in proton-proton collisions at $\sqrt{s}$ = 13.6 TeV

The CMS collaboration Hayrapetyan, Aram ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
Phys.Lett.B 861 (2025) 139231, 2025.
Inspire Record 2796231 DOI 10.17182/hepdata.150773

Measurements at $\sqrt{s}$ = 13.6 TeV of the opposite-sign W boson pair production cross section in proton-proton collisions are presented. The data used in this study were collected with the CMS detector at the CERN LHC in 2022, and correspond to an integrated luminosity of 34.8 fb$^{-1}$. Events are selected by requiring one electron and one muon of opposite charge. A maximum likelihood fit is performed on signal- and background-enriched data categories defined by the flavour and charge of the leptons, the number of jets, and number of jets originating from b quarks. An inclusive W$^+$W$^-$ production cross section of 125.7 $\pm$ 5.6 pb is measured, in agreement with standard model predictions. Cross sections are also reported in a fiducial region close to that of the detector acceptance, both inclusively and differentially, as a function of the jet multiplicity in the event. For first time in proton-proton collisions, WW events with at least two reconstructed jets are studied and compared with recent theoretical predictions.

12 data tables

Summary of inclusive cross section.

Summary of inclusive cross section.

Relative systematic uncertainties in the total cross section measurement.

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Observation of four top quark production in proton-proton collisions at $\sqrt{s}$ = 13 TeV

The CMS collaboration Hayrapetyan, Aram ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
Phys.Lett.B 847 (2023) 138290, 2023.
Inspire Record 2661880 DOI 10.17182/hepdata.138420

The observation of the production of four top quarks in proton-proton collisions is reported, based on a data sample collected by the CMS experiment at a center-of-mass energy of 13 TeV in 2016-2018 at the CERN LHC and corresponding to an integrated luminosity of 138 fb$^{-1}$. Events with two same-sign, three, or four charged leptons (electrons and muons) and additional jets are analyzed. Compared to previous results in these channels, updated identification techniques for charged leptons and jets originating from the hadronization of b quarks, as well as a revised multivariate analysis strategy to distinguish the signal process from the main backgrounds, lead to an improved expected signal significance of 4.9 standard deviations above the background-only hypothesis. Four top quark production is observed with a significance of 5.6 standard deviations, and its cross section is measured to be 17.7 $^{+3.7}_{-3.5}$ (stat) $^{+2.3}_{-1.9}$ (syst) fb, in agreement with the available standard model predictions.

2 data tables

Comparison of fit results in the channels individually and in their combination. The left panel shows the values of the measured cross section relative to the SM prediction from Ref. [6]. The right panel shows the expected and observed significance, with the printed values rounded to the first decimal.

Number of predicted and observed events in the SR-2$\ell$ and SR-3$\ell$ $t\bar{t}t\bar{t}$ classes, both before the fit to the data ("prefit") and with their best fit normalizations ("postfit"). The uncertainties in the predicted number of events include both the statistical and systematic components. The uncertainties in the total number of predicted background and background plus signal events are also given.


Measurement of the jet mass distribution and top quark mass in hadronic decays of boosted top quarks in proton-proton collisions at $\sqrt{s}$ = 13 TeV

The CMS collaboration Tumasyan, Armen ; Adam, Wolfgang ; Andrejkovic, Janik Walter ; et al.
Eur.Phys.J.C 83 (2023) 560, 2023.
Inspire Record 2175946 DOI 10.17182/hepdata.130712

A measurement of the jet mass distribution in hadronic decays of Lorentz-boosted top quarks is presented. The measurement is performed in the lepton+jets channel of top quark pair production ($\mathrm{t\bar{t}}$) events, where the lepton is an electron or muon. The products of the hadronic top quark decay are reconstructed using a single large-radius jet with transverse momentum greater than 400 GeV. The data were collected with the CMS detector at the LHC in proton-proton collisions and correspond to an integrated luminosity of 138 fb$^{-1}$. The differential $\mathrm{t\bar{t}}$ production cross section as a function of the jet mass is unfolded to the particle level and is used to extract the top quark mass. The jet mass scale is calibrated using the hadronic W boson decay within the large-radius jet. The uncertainties in the modelling of the final state radiation are reduced by studying angular correlations in the jet substructure. These developments lead to a significant increase in precision, and a top quark mass of 173.06 $\pm$ 0.84 GeV.

14 data tables

The particle-level $\mathrm{t}\overline{\mathrm{t}}$ differential cross section in the fiducial region as a function of the XCone-jet mass.

Correlations between bins in the particle-level $\mathrm{t}\overline{\mathrm{t}}$ differential cross section as a function of the XCone-jet mass.

The covariance matrix containing the statistical uncertainties of the particle-level $\mathrm{t}\overline{\mathrm{t}}$ differential cross section as a function of the XCone-jet mass.

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Azimuthal correlations in Z+jets events in proton-proton collisions at $\sqrt{s}$ = 13 TeV

The CMS collaboration Tumasyan, Armen ; Adam, Wolfgang ; Andrejkovic, Janik Walter ; et al.
Eur.Phys.J.C 83 (2023) 722, 2023.
Inspire Record 2172990 DOI 10.17182/hepdata.133278

The production of Z bosons associated with jets is measured in pp collisions at $\sqrt{s}$ = 13 TeV with data recorded with the CMS experiment at the LHC corresponding to an integrated luminosity of 36.3 fb$^{-1}$. The multiplicity of jets with transverse momentum $p_\mathrm{T}$$\gt$ 30 GeV is measured for different regions of the Z boson's $p_\mathrm{T}$(Z), from lower than 10 GeV to higher than 100 GeV. The azimuthal correlation $\Delta \phi$ between the Z boson and the leading jet, as well as the correlations between the two leading jets are measured in three regions of $p_\mathrm{T}$(Z). The measurements are compared with several predictions at leading and next-to-leading orders, interfaced with parton showers. Predictions based on transverse-momentum dependent parton distributions and corresponding parton showers give a good description of the measurement in the regions where multiple parton interactions and higher jet multiplicities are not important. The effects of multiple parton interactions are shown to be important to correctly describe the measured spectra in the low $p_\mathrm{T}$(Z) regions.

15 data tables

The measured cross section as a function of exclusive jet multiplicity, $N_{\text{jets}}$, when $p_T<10$ GeV

The measured cross section as a function of exclusive jet multiplicity, $N_{\text{jets}}$, when $10<p_T<30$ GeV

The measured cross section as a function of exclusive jet multiplicity, $N_{\text{jets}}$, when $30<p_T<50$ GeV

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Searches for additional Higgs bosons and for vector leptoquarks in $\tau\tau$ final states in proton-proton collisions at $\sqrt{s}$ = 13 TeV

The CMS collaboration Tumasyan, Armen ; Adam, Wolfgang ; Andrejkovic, Janik Walter ; et al.
JHEP 07 (2023) 073, 2023.
Inspire Record 2132368 DOI 10.17182/hepdata.128147

Three searches are presented for signatures of physics beyond the standard model (SM) in $\tau\tau$ final states in proton-proton collisions at the LHC, using a data sample collected with the CMS detector at $\sqrt{s}$ = 13 TeV, corresponding to an integrated luminosity of 138 fb$^{-1}$. Upper limits at 95% confidence level (CL) are set on the products of the branching fraction for the decay into $\tau$ leptons and the cross sections for the production of a new boson $\phi$, in addition to the H(125) boson, via gluon fusion (gg$\phi$) or in association with b quarks, ranging from $\mathcal{O}$(10 pb) for a mass of 60 GeV to 0.3 fb for a mass of 3.5 TeV each. The data reveal two excesses for gg$\phi$ production with local $p$-values equivalent to about three standard deviations at $m_\phi$ = 0.1 and 1.2 TeV. In a search for $t$-channel exchange of a vector leptoquark U$_1$, 95% CL upper limits are set on the dimensionless U$_1$ leptoquark coupling to quarks and $\tau$ leptons ranging from 1 for a mass of 1 TeV to 6 for a mass of 5 TeV, depending on the scenario. In the interpretations of the $M_\mathrm{h}^{125}$ and $M_\mathrm{h, EFT}^{125}$ minimal supersymmetric SM benchmark scenarios, additional Higgs bosons with masses below 350 GeV are excluded at 95% CL.

313 data tables

Expected and observed $95\%\text{ CL}$ upper limits on the product of the cross sections and branching fraction for the decay into $\tau$ leptons for $gg\phi$ production in a mass range of $60\leq m_\phi\leq 3500\text{ GeV}$, in addition to $\text{H}(125)$. The central $68$ and $95\%$ intervals are given in addition to the expected median value. In this case, $bb\phi$ production rate has been profiled. The peak in the expected $gg\phi$ limit is tribute to a loss of sensitivity around $90\text{ GeV}$ due to the background from $Z/\gamma^\ast\rightarrow\tau\tau$ events. Numerical values provided in this table correspond to Figure 10a of the publication.

Expected and observed $95\%\text{ CL}$ upper limits on the product of the cross sections and branching fraction for the decay into $\tau$ leptons for $bb\phi$ production in a mass range of $60\leq m_\phi\leq 3500\text{ GeV}$, in addition to $\text{H}(125)$. The central $68$ and $95\%$ intervals are given in addition to the expected median value. In this case, $gg\phi$ production rate has been profiled. Numerical values provided in this table correspond to Figure 10b of the publication.

Expected and observed $95\%\text{ CL}$ upper limits on the product of the cross sections and branching fraction for the decay into $\tau$ leptons for $gg\phi$ production in a mass range of $60\leq m_\phi\leq 3500\text{ GeV}$, in addition to $\text{H}(125)$. The central $68$ and $95\%$ intervals are given in addition to the expected median value. In this case, $bb\phi$ production rate has been fixed to zero. Numerical values provided in this table correspond to Figure 37 of the auxilliary material of the publication.

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Version 2
Measurement of the top quark pole mass using $\mathrm{t\bar{t}}$+jet events in the dilepton final state in proton-proton collisions at $\sqrt{s}$ = 13 TeV

The CMS collaboration Tumasyan, Armen ; Adam, Wolfgang ; Andrejkovic, Janik Walter ; et al.
JHEP 07 (2023) 077, 2023.
Inspire Record 2106483 DOI 10.17182/hepdata.127990

A measurement of the top quark pole mass $m_\mathrm{t}^\text{pole}$ in events where a top quark-antiquark pair ($\mathrm{t\bar{t}}$) is produced in association with at least one additional jet ($\mathrm{t\bar{t}}$+jet) is presented. This analysis is performed using proton-proton collision data at $\sqrt{s}$ = 13 TeV collected by the CMS experiment at the CERN LHC, corresponding to a total integrated luminosity of 36.3 fb$^{-1}$. Events with two opposite-sign leptons in the final state (e$^+$e$^-$, $\mu^+\mu^-$, e$^\pm\mu^\mp$) are analyzed. The reconstruction of the main observable and the event classification are optimized using multivariate analysis techniques based on machine learning. The production cross section is measured as a function of the inverse of the invariant mass of the $\mathrm{t\bar{t}}$+jet system at the parton level using a maximum likelihood unfolding. Given a reference parton distribution function (PDF), the top quark pole mass is extracted using the theoretical predictions at next-to-leading order. For the ABMP16NLO PDF, this results in $m_\mathrm{t}^\text{pole}$ = 172.93 $\pm$ 1.36 GeV.

20 data tables

Absolute differential cross section as a function of the rho observable at parton level.

Absolute differential cross section as a function of the rho observable at parton level.

Covariance matrix for the total uncertainty for the measurement of the absolute differential cross section as a function of the rho observable at parton level.

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