Observation of the $\Xi^-_\mathrm{b}$$\to$$\psi$(2S)$\Xi^-$ decay and studies of the $\Xi_\mathrm{b}^{\ast{}0}$ baryon in proton-proton collisions at $\sqrt{s}$ = 13 TeV

The CMS collaboration Hayrapetyan, Aram ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
CMS-BPH-23-002, 2024.
Inspire Record 2762139 DOI 10.17182/hepdata.146756

The first observation of the decay $\Xi^-_\mathrm{b}$$\to$$\psi$(2S)$\Xi^-$ and measurement of the branching ratio of $\Xi^-_\mathrm{b}$$\to$$\psi$(2S)$\Xi^-$ to $\Xi^-_\mathrm{b}$$\to$ J/$\psi$$\Xi^-$ are presented. The J/$\psi$ and $\psi$(2S) mesons are reconstructed using their dimuon decay modes. The results are based on proton-proton colliding beam data from the LHC collected by the CMS experiment at $\sqrt{s}$ = 13 TeV in 2016-2018, corresponding to an integrated luminosity of 140 fb$^{-1}$. The branching fraction ratio is measured to be $\mathcal{B}$($\Xi^-_\mathrm{b}$$\to$$\psi$(2S)$\Xi^-$)/$\mathcal{B}$($\Xi^-_\mathrm{b}$$\to$ J/$\psi$$\Xi^-$) = 0.84$^{+0.21}_{-0.19}$ (stat) $\pm$ 0.10 (syst) $\pm$ 0.02 ($\mathcal{B}$), where the last uncertainty comes from the uncertainties in the branching fractions of the charmonium states. New measurements of the $\Xi_\mathrm{b}^{\ast{}0}$ baryon mass and natural width are also presented, using the $\Xi_\mathrm{b}^-\pi^+$ final state, where the $\Xi^-_\mathrm{b}$ baryon is reconstructed through the decays J/$\psi \Xi^-$, $\psi$(2S)$\Xi^-$, J/$\psi \Lambda$K$^-$, and J/$\psi \Sigma^0$K$^-$. Finally, the fraction of the $\Xi^-_\mathrm{b}$ baryons produced from $\Xi_\mathrm{b}^{\ast{}0}$ decays is determined.

5 data tables

The measured ratio of branching fractions

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Search for Resonant Production of Dark Quarks in the Dijet Final State with the ATLAS Detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abeling, Kira ; et al.
JHEP 02 (2024) 128, 2024.
Inspire Record 2719976 DOI 10.17182/hepdata.145191

This paper presents a search for a new $Z^\prime$ resonance decaying into a pair of dark quarks which hadronise into dark hadrons before promptly decaying back as Standard Model particles. This analysis is based on proton-proton collision data recorded at $\sqrt{s}=13$ TeV with the ATLAS detector at the Large Hadron Collider between 2015 and 2018, corresponding to an integrated luminosity of 139 fb$^{-1}$. After selecting events containing large-radius jets with high track multiplicity, the invariant mass distribution of the two highest-transverse-momentum jets is scanned to look for an excess above a data-driven estimate of the Standard Model multijet background. No significant excess of events is observed and the results are thus used to set 95 % confidence-level upper limits on the production cross-section times branching ratio of the $Z^\prime$ to dark quarks as a function of the $Z^\prime$ mass for various dark-quark scenarios.

13 data tables

Distribution of the di-jet invariant mass, $m_{\mathrm{JJ}}$ for the data, the simulated multi-jet background and of some representative signals (models A, B, C and D with $m_{Z'}=2.5$ TeV), shown after applying the preselections described in the text. The simulated background is normalised to the data and the signals are normalised to a production cross-section of 10 fb.

Distributions of the number of tracks associated to the leading jet, $n_{track,1}$, for the data, the simulated multi-jet background and of some representative signals (models A, B, C and D with $m_{Z^\prime}=2.5$ TeV), shown after applying the preselections described in the text. All distributions are normalised to unity. The uncertainty band around the background prediction corresponds to the modelling uncertainty described in Section 6.

Distributions of the number of tracks associated to the subleading jet, $n_{track,2}$, for the data, the simulated multi-jet background and of some representative signals (models A, B, C and D with $m_{Z^\prime}=2.5$ TeV), shown after applying the preselections described in the text. All distributions are normalised to unity. The uncertainty band around the background prediction corresponds to the modelling uncertainty described in Section 6.

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Observation of new structure in the J/$\psi$J/$\psi$ mass spectrum in proton-proton collisions at $\sqrt{s}$ = 13 TeV

The CMS collaboration Hayrapetyan, Aram ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
CMS-BPH-21-003, 2023.
Inspire Record 2668013 DOI 10.17182/hepdata.141028

A search is reported for near-threshold structures in the J/$\psi$J/$\psi$ invariant mass spectrum produced in proton-proton collisions at $\sqrt{s}$ = 13 TeV from data collected by the CMS experiment, corresponding to an integrated luminosity of 135 fb$^{-1}$. A new structure is observed with a significance above 5 standard deviations at a mass of 6552 $\pm$ 10 (stat) $\pm$ 12 (syst) MeV. Another structure with even higher significance is found at a mass of 6927 $\pm$ 9 (stat) $\pm$ 4 (syst) MeV, which is consistent with the X(6900) resonance reported by the LHCb experiment and confirmed by the ATLAS experiment. Evidence for another new structure, with a local significance of 4.1 standard deviations, is found at a mass of 7287$^{+20}_{-18}$ (stat) $\pm$ 5 (syst) MeV. The masses and significances are obtained in a model without considering possible quantum mechanical interference between the resonances. Incorporating this interference provides a better description of the mass spectrum between the resonances and shifts the measured masses by up to 150 MeV.

2 data tables

The mass (m) and natural widths (Γ) from the fits to the $\mathrm{J}/\psi\mathrm{J}/\psi$ mass distribution, for both the non-interference model and the interference model. The signal yields N for the non-interference model are given for the three signal structures.

The $\mathrm{J}/\psi\mathrm{J}/\psi$ invariant mass distribution in data


Measurement of the top quark mass using a profile likelihood approach with the lepton+jets final states 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) 963, 2023.
Inspire Record 2629755 DOI 10.17182/hepdata.127993

The mass of the top quark is measured in 36.3 fb$^{-1}$ of LHC proton-proton collision data collected with the CMS detector at $\sqrt{s}$ = 13 TeV. The measurement uses a sample of top quark pair candidate events containing one isolated electron or muon and at least four jets in the final state. For each event, the mass is reconstructed from a kinematic fit of the decay products to a top quark pair hypothesis. A profile likelihood method is applied using up to four observables to extract the top quark mass. The top quark mass is measured to be 171.77 $\pm$ 0.37 GeV. This approach significantly improves the precision over previous measurements.

2 data tables

Fit values for the top quark mass value and the nuisance parameters corresponding to the different uncertainty sources. All nuisance parameters have a prefit uncertainty of 1.

Covariance matrix for the top quark mass value and the nuisance parameters corresponding to the different uncertainty sources. All nuisance parameters have a prefit uncertainty of 1. The (statistical) uncertainty in mTop in the matrix includes the contributions from limited simulation sample sizes.


Search for new physics in the lepton plus missing transverse momentum 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 (2022) 067, 2022.
Inspire Record 2618188 DOI 10.17182/hepdata.106058

A search for physics beyond the standard model (SM) in final states with an electron or muon and missing transverse momentum is presented. The analysis uses data from proton-proton collisions at a centre-of-mass energy of 13 TeV, collected with the CMS detector at the LHC in 2016–2018 and corresponding to an integrated luminosity of 138 fb−1. No significant deviation from the SM prediction is observed. Model-independent limits are set on the production cross section of W’ bosons decaying into lepton-plus-neutrino final states. Within the framework of the sequential standard model, with the combined results from the electron and muon decay channels a W’ boson with mass less than 5.7 TeV is excluded at 95% confidence level. Results on a SM precision test, the determination of the oblique electroweak W parameter, are presented using LHC data for the first time. These results together with those from the direct W’ resonance search are used to extend existing constraints on composite Higgs scenarios. This is the first experimental exclusion on compositeness parameters using results from LHC data other than Higgs boson measurements.

26 data tables

Product of signal selection efficiency and acceptance as a function of resonance mass for a SSM WPRIME decaying to electron or muon plus neutrino.It is calculated as the number of WPRIME signal events passing the selection process over the number of generated events. In the selection process there is no requirement on a minimum $M_T$ applied. The SSM WPRIME signal samples have been generated with PYTHIA 8.2. More details in paper

Observed and expected number of events in the electron and muon channels, collected during three years (2016, 2017, and 2018), for selected values of $M_T$ thresholds. The statistical and systematic uncertainties are added in quadrature providing the total uncertainty.

Observed and expected-from-SM number of events in the electron and muon channels, collected during three years (2016, 2017, and 2018), for two steps in the selection procedure: 1) one high-quality high-$p_T$ lepton with $p_T$ > 240(53) GeV for E(MU), and no other lepton in the event, with $M_T$ > 400(120) GeV for events with E(MU). 2) additionally the ratio of the lepton $p_T$ and $p_T^{miss}$ must be 0.4 < $p_T$/$p_T^{miss}$ < 1.5 and the azimuthal angular difference between them, ${\Delta\phi}$> 2.5. The signal yield for an SSM WPRIME of mass 5.6 TeV is also included.

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Search for boosted diphoton resonances in the 10 to 70 GeV mass range using 138 fb$^{-1}$ of 13 TeV $pp$ collisions with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, D.C. ; et al.
JHEP 07 (2023) 155, 2023.
Inspire Record 2178061 DOI 10.17182/hepdata.131600

A search for diphoton resonances in the mass range between 10 and 70 GeV with the ATLAS experiment at the Large Hadron Collider (LHC) is presented. The analysis is based on $pp$ collision data corresponding to an integrated luminosity of 138 fb$^{-1}$ at a centre-of-mass energy of 13 TeV recorded from 2015 to 2018. Previous searches for diphoton resonances at the LHC have explored masses down to 65 GeV, finding no evidence of new particles. This search exploits the particular kinematics of events with pairs of closely spaced photons reconstructed in the detector, allowing examination of invariant masses down to 10 GeV. The presented strategy covers a region previously unexplored at hadron colliders because of the experimental challenges of recording low-energy photons and estimating the backgrounds. No significant excess is observed and the reported limits provide the strongest bound on promptly decaying axion-like particles coupling to gluons and photons for masses between 10 and 70 GeV.

7 data tables

The expected and observed upper limits at 95\% CL on the fiducial cross-section times branching ratio to two photons of a narrow-width ($\Gamma_{X}$ = 4 MeV) scalar resonance as a function of its mass $m_{X}$.

Diphoton invariant mass in the signal region using a 0.1 GeV binning.

Parametrization of the $C_{X}$ factor, defined as the ratio between the number of reconstructed signal events passing the analysis cuts and the number of signal events at the particle level generated within the fiducial volume, as function of $m_{X}$ obtained from the narrow width simulated signal samples produced in gluon fusion.

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Search for pair production of vector-like quarks in leptonic 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) 020, 2023.
Inspire Record 2152227 DOI 10.17182/hepdata.129875

A search is presented for vector-like T and B quark-antiquark pairs produced in proton-proton collisions at a center-of-mass energy of 13 TeV. Data were collected by the CMS experiment at the CERN LHC in 2016-2018, with an integrated luminosity of 138 fb$^{-1}$. Events are separated into single-lepton, same-sign charge dilepton, and multilepton channels. In the analysis of the single-lepton channel a multilayer neural network and jet identification techniques are employed to select signal events, while the same-sign dilepton and multilepton channels rely on the high-energy signature of the signal to distinguish it from standard model backgrounds. The data are consistent with standard model background predictions, and the production of vector-like quark pairs is excluded at 95% confidence level for T quark masses up to 1.54 TeV and B quark masses up to 1.56 TeV, depending on the branching fractions assumed, with maximal sensitivity to decay modes that include multiple top quarks. The limits obtained in this search are the strongest limits to date for $\mathrm{T\overline{T}}$ production, excluding masses below 1.48 TeV for all decays to third generation quarks, and are the strongest limits to date for $\mathrm{B\overline{B}}$ production with B quark decays to tW.

46 data tables

Distribution of ST in the training region for the $T\overline{T}$ MLP. The observed data are shown along with the predicted $T\overline{T}$ signal with mass of 1.2 (1.5) TeV in the singlet scenario and the background. Statistical and systematic uncertainties in the background prediction before performing the fit to data are also shown. The signal predictions of 1.2 TeV and 1.5 TeV signals have been scaled by factors of x300 and x600, respectively, for visibility.

Distribution of the leading jet’s DEEPAK8 light quark or gluon score in the training region for the $T\overline{T}$ MLP. The observed data are shown along with the predicted $T\overline{T}$ signal with mass of 1.2 (1.5) TeV in the singlet scenario and the background. Statistical and systematic uncertainties in the background prediction before performing the fit to data are also shown. The signal predictions of 1.2 TeV and 1.5 TeV signals have been scaled by factors of x300 and x600, respectively, for visibility.

Distribution of the MLP T quark score in the SR for the $T\overline{T}$ search. The observed data, predicted $T\overline{T}$ signal with mass of 1.2 (1.5) TeV in the singlet scenario, and the background are all shown. Statistical and systematic uncertainties in the background prediction before performing the fit to data are also shown. The signal predictions of 1.2 TeV and 1.5 TeV signals have been scaled by factors of x10 and x20, respectively, for visibility.

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Version 2
Search for long-lived particles decaying into muon pairs in proton-proton collisions at $\sqrt{s}$ = 13 TeV collected with a dedicated high-rate data stream

The CMS collaboration Tumasyan, Armen ; Adam, Wolfgang ; Andrejkovic, Janik Walter ; et al.
JHEP 04 (2022) 062, 2022.
Inspire Record 1997201 DOI 10.17182/hepdata.115577

A search for long-lived particles decaying into muon pairs is performed using proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS experiment at the LHC in 2017 and 2018, corresponding to an integrated luminosity of 101 fb$^{-1}$. The data sets used in this search were collected with a dedicated dimuon trigger stream with low transverse momentum thresholds, recorded at high rate by retaining a reduced amount of information, in order to explore otherwise inaccessible phase space at low dimuon mass and nonzero displacement from the primary interaction vertex. No significant excess of events beyond the standard model expectation is found. Upper limits on branching fractions at 95% confidence level are set on a wide range of mass and lifetime hypotheses in beyond the standard model frameworks with the Higgs boson decaying into a pair of long-lived dark photons, or with a long-lived scalar resonance arising from a decay of a b hadron. The limits are the most stringent to date for substantial regions of the parameter space. These results can be also used to constrain models of displaced dimuons that are not explicitly considered in this paper.

45 data tables

Expected and observed limits at 95% CL on the branching fraction B(hb --> PHI X) . B(PHI --> mu+mu-) as a function of signal mass for signal lifetime of 1 mm

Expected and observed limits at 95% CL on the branching fraction B(hb --> PHI X) . B(PHI --> mu+mu-) as a function of signal mass for signal lifetime of 1 mm

Expected and observed limits at 95% CL on the branching fraction B(hb --> PHI X) . B(PHI --> mu+mu-) as a function of signal mass for signal lifetime of 100 mm

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Version 2
Observation of triple J/$\psi$ meson production in proton-proton collisions at $\sqrt{s}$ = 13 TeV

The CMS collaboration Tumasyan, Armen ; Adam, Wolfgang ; Andrejkovic, Janik Walter ; et al.
Nature Phys. 19 (2023) 338 338-350, 2023.
Inspire Record 1965242 DOI 10.17182/hepdata.114984

Protons consist of three valence quarks, two up-quarks and one down-quark, held together by gluons and a sea of quark-antiquark pairs. Collectively, quarks and gluons are referred to as partons. In a proton-proton collision, typically only one parton of each proton undergoes a hard scattering - referred to as single-parton scattering - leaving the remainder of each proton only slightly disturbed. Here, we report the study of double- and triple-parton scatterings through the simultaneous production of three J/$\psi$ mesons, which consist of a charm quark-antiquark pair, in proton-proton collisions recorded with the CMS experiment at the Large Hadron Collider. We observed this process - reconstructed through the decays of J/$\psi$ mesons into pairs of oppositely charged muons - with a statistical significance above five standard deviations. We measured the inclusive fiducial cross section to be 272 $^{+141}_{-104}$ (stat) $\pm$ 17 (syst) fb, and compared it to theoretical expectations for triple-J/$\psi$ meson production in single-, double- and triple-parton scattering scenarios. Assuming factorization of multiple hard-scattering probabilities in terms of single-parton scattering cross sections, double- and triple-parton scattering are the dominant contributions for the measured process.

6 data tables

Kinematic properties of each one of the three \JPsi mesons selected in the 5? 6? signal events.

Dimuon invariant mass ($m$), proper decay-length ($L$), transverse momentum ($p_{T}$), rapidity ($y$), and azimuthal angle ($\phi$) of each of the three $J/\psi$ candidates measured in the six triple-$J/\psi$ events passing our selection criteria.

DPS effective cross section

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Observation of a new excited beauty strange baryon decaying to $\Xi^-_\mathrm{b} \pi^+ \pi^-$

The CMS collaboration Sirunyan, Albert M ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
Phys.Rev.Lett. 126 (2021) 252003, 2021.
Inspire Record 1845579 DOI 10.17182/hepdata.102493

The $\Xi^-_\mathrm{b} \pi^+ \pi^-$ invariant mass spectrum is investigated with an event sample of proton-proton collisions at $\sqrt{s} = $ 13 TeV, collected by the CMS experiment at the LHC in 2016-2018 and corresponding to an integrated luminosity of 140 fb$^{-1}$. The ground state $\Xi^-_\mathrm{b}$ is reconstructed via its decays to J$/\psi \Xi^-$ and J$/\psi \Xi^-\Lambda$K$^-$. A narrow resonance, labeled $\Xi_\mathrm{b}$(6100)$^-$, is observed at a $\Xi^-_\mathrm{b} \pi^+ \pi^-$ invariant mass of 6100.3 $\pm$ 0.2 (stat) $\pm$ 0.1 (syst) $\pm$ 0.6 ($\Xi^-_\mathrm{b}$) MeV, where the last uncertainty reflects the precision of the $\Xi^-_\mathrm{b}$ baryon mass. The upper limit on the $\Xi_\mathrm{b}$(6100)$^-$ natural width is determined to be 1.9 MeV at 95% confidence level. Following analogies with the established excited $\Xi_\mathrm{c}$ baryon states, the new $\Xi_\mathrm{b}$(6100)$^-$ resonance and its decay sequence are consistent with the orbitally excited $\Xi^-_\mathrm{b}$ baryon, with spin and parity quantum numbers $J^P=$ 3/2$^-$.

3 data tables