Study of charm hadronization with prompt $\Lambda^+_\mathrm{c}$ baryons in proton-proton and lead-lead collisions at $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV

The CMS collaboration Tumasyan, Armen ; Adam, Wolfgang ; Andrejkovic, Janik Walter ; et al.
JHEP 01 (2024) 128, 2024.
Inspire Record 2679262 DOI 10.17182/hepdata.135973

The production of prompt $\Lambda^+_\mathrm{c}$ baryons is measured via the exclusive decay channel $\Lambda^+_\mathrm{c}$$\to$ pK$^-\pi^+$ at a center-of-mass energy per nucleon pair of 5.02 TeV, using proton-proton (pp) and lead-lead (PbPb) collision data collected by the CMS experiment at the CERN LHC. The pp and PbPb data were obtained in 2017 and 2018 with integrated luminosities of 252 and 0.607 nb$^{-1}$, respectively. The measurements are performed within the $\Lambda^+_\mathrm{c}$ rapidity interval $\vert y \vert$$\lt$ 1 with transverse momentum ($p_\mathrm{T}$) ranges of 3-30 and 6-40 GeV/$c$ for pp and PbPb collisions, respectively. Compared to the yields in pp collisions scaled by the expected number of nucleon-nucleon interactions, the observed yields of $\Lambda^+_\mathrm{c}$ with $p_\mathrm{T}$$\gt$ 10 GeV/$c$ are strongly suppressed in PbPb collisions. The level of suppression depends significantly on the collision centrality. The $\Lambda^+_\mathrm{c}$ / D$^0$ production ratio is similar in PbPb and pp collisions at $p_\mathrm{T}$$\gt$ 10 GeV/$c$, suggesting that the coalescence process does not play a dominant role in prompt $\Lambda^+_\mathrm{c}$ baryon production at higher $p_\mathrm{T}$.

6 data tables

The product of acceptance and efficiency ($A \epsilon$) as a function of $p_{\mathrm{T}}$ for prompt $\Lambda^+_c$ in pp collisions and within centrality regions of 0-90, 0-10, 10-30, 30-50 and 50-90% in PbPb collisions.

The $p_{\mathrm{T}}$ differential cross sections for prompt $\Lambda^+_c$ production in pp collisions. The global fit uncertainty is 8.6%.

The $\mathrm{T_{AA}}$-scaled $\Lambda^+_c$ yields as a function of $p_{\mathrm{T}}$ for PbPb collisions within centrality regions of 0-90, 0-10, 10-30, 30-50 and 50-90%.

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Multiplicity and transverse momentum dependence of charge-balance functions in pPb and PbPb collisions at LHC energies

The CMS collaboration Tumasyan, Armen ; Adam, Wolfgang ; Andrejkovic, Janik Walter ; et al.
CMS-HIN-21-017, 2023.
Inspire Record 2679254 DOI 10.17182/hepdata.135972

Measurements of the charge-dependent two-particle angular correlation function in proton-lead (pPb) collisions at a nucleon-nucleon center-of-mass energy of $\sqrt{s_\mathrm{NN}}$ = 8.16 TeV and lead-lead (PbPb) collisions at$\sqrt{s_\mathrm{NN}}$ = 5.02 TeV are reported. The pPb and PbPb datasets correspond to integrated luminosities of 186\nbinv and 0.607 nb$^{-1}$, respectively, and were collected using the CMS detector at the CERN LHC. The charge-dependent correlations are characterized by balance functions of same- and opposite-sign particle pairs. The balance functions, which contain information about the creation time of charged particle pairs and the development of collectivity, are studied as functions of relative pseudorapidity ($\Delta \eta$) and relative azimuthal angle ($\Delta \phi$), for various multiplicity and transverse momentum ($p_\mathrm{T}$) intervals. A multiplicity dependence of the balance function is observed in $\Delta \eta$ and $\Delta \phi$ for both systems. The width of the balance functions decreases towards high-multiplicity collisions in the momentum region $\lt$2 GeV, for pPb and PbPb results. No multiplicity dependence is observed at higher transverse momentum. The data are compared with HYDJET, HIJING and AMPT generator predictions, none of which capture completely the multiplicity dependence seen in the data.

56 data tables

$\Delta\eta$ projection of balance function in low $p_{T}$ in 0-10% centrality

$\Delta\eta$ projection of balance function in low $p_{T}$ in 30-40% centrality

$\Delta\eta$ projection of balance function in low $p_{T}$ in 70-80% centrality

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Search for a high-mass dimuon resonance produced in association with b quark jets at $\sqrt{s}$=13 TeV

The CMS collaboration Hayrapetyan, Aram ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
JHEP 10 (2023) 043, 2023.
Inspire Record 2678141 DOI 10.17182/hepdata.141455

A search for high-mass dimuon resonance production in association with one or more b quark jets is presented. The study uses proton-proton collision data collected with the CMS detector at the LHC corresponding to an integrated luminosity of 138 fb$^{-1}$ at a center-of-mass energy of 13 TeV. Model-independent limits are derived on the number of signal events with exactly one or more than one b quark jet. Results are also interpreted in a lepton-flavor-universal model with Z$'$ boson couplings to a bb quark pair ($g_\mathrm{b}$), an sb quark pair ($g_\mathrm{b}\delta_\mathrm{bs}$), and any same-flavor charged lepton ($g_\ell$) or neutrino pair ($g_\nu$), with $\left|g_{\nu}\right| = \left|g_\ell\right|$. For a Z$'$ boson with a mass $m_{\mathrm{Z}'}$ = 350 GeV (2 TeV) and $\left|\delta_\mathrm{bs}\right|$$\lt$ 0.25, the majority of the parameter space with 0.0057 $\lt$$\left|g_\ell\right|$$\lt$ 0.35 (0.25 $\lt$$\left|g_\ell\right|$$\lt$ 0.43) and 0.0079 $\lt$$\left|g_\mathrm{b}\right|$$\lt$ 0.46 (0.34 $\lt$$\left|g_\mathrm{b}\right|$$\lt$ 0.57) is excluded at 95% confidence level. Finally, constraints are set on a Z$'$ model with parameters consistent with low-energy b $\to$ s$\ell\ell$ measurements. In this scenario, most of the allowed parameter space is excluded for a Z$'$ boson with 350 $\lt m_{\mathrm{Z}'}$ $\lt$ 500 GeV, while the constraints are less stringent for higher $m_{\mathrm{Z}'}$ hypotheses. This is the first dedicated search at the LHC for a high-mass dimuon resonance produced in association with multiple b quark jets, and the constraints obtained on models with this signature are the most stringent to date.

69 data tables

Feynman diagrams of $\mathrm{Z'}\to\mu^{-}\mu^{+}$ with a $\mathrm{Z'}$ boson produced via $\mathrm{b}\overline{\mathrm{b}}\to\mathrm{Z'}$, with one $\mathrm{b}$ quark in the final state.

Feynman diagrams of $\mathrm{Z'}\to\mu^{-}\mu^{+}$ with a $\mathrm{Z'}$ boson produced via $\mathrm{s}\overline{\mathrm{b}}\to\mathrm{Z'}$, with one $\mathrm{b}$ quark in the final state.

Feynman diagrams of $\mathrm{Z'}\to\mu^{-}\mu^{+}$ with a $\mathrm{Z'}$ boson produced via $\mathrm{b}\overline{\mathrm{b}}\to\mathrm{Z'}$, with two $\mathrm{b}$ quarks in the final state.

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Search for Z' bosons decaying to pairs of heavy Majorana neutrinos in proton-proton collisions at $\sqrt{s}$ = 13 TeV

The CMS collaboration Tumasyan, Armen ; Adam, Wolfgang ; Andrejkovic, Janik Walter ; et al.
JHEP 11 (2023) 181, 2023.
Inspire Record 2677273 DOI 10.17182/hepdata.141323

A search for the production of pairs of heavy Majorana neutrinos (N$_\ell$) from the decays of Z' bosons is performed using the CMS detector at the LHC. The data were collected in proton-proton collisions at a center-of-mass energy of $\sqrt{s}$ = 13 TeV, with an integrated luminosity of 138 fb$^{-1}$. The signature for the search is an excess in the invariant mass distribution of the final-state objects, two same-flavor leptons (e or $\mu$) and at least two jets. No significant excess of events beyond the expected background is observed. Upper limits at 95% confidence level are set on the product of the Z' production cross section and its branching fraction to a pair of N$_\ell$, as functions of N$_\ell$ and Z' boson masses ($m_{\mathrm{N}_\ell}$ and $m_\mathrm{Z'}$, respectively) for $m_\mathrm{Z'}$ from 0.4 to 4.6 TeV and $m_{\mathrm{N}_\ell}$ from 0.1 TeV to $m_\mathrm{Z'}$/2. In the theoretical framework of a left-right symmetric model, exclusion bounds in the $m_{\mathrm{N}_\ell}-m_\mathrm{Z'}$ plane are presented in both the electron and muon channels. The observed upper limit on $m_\mathrm{Z'}$ reaches up to 4.42 TeV. These are the most restrictive limits to date on the mass of N$_\ell$ as a function of the Z' boson mass.

24 data tables

Reconstructed mass of the Z' candidate in CR1, which consists of flavor sidebands of SR1 (upper), SR2 (middle), and SR3 (lower) regions. Pre-fit (post-fit) results are shown on the left (right). The fitting procedure is described in Section 7.

Reconstructed mass of the Z' candidate in CR1, which consists of flavor sidebands of SR1 (upper), SR2 (middle), and SR3 (lower) regions. Pre-fit (post-fit) results are shown on the left (right). The fitting procedure is described in Section 7.

Reconstructed mass of the Z' candidate in CR1, which consists of flavor sidebands of SR1 (upper), SR2 (middle), and SR3 (lower) regions. Pre-fit (post-fit) results are shown on the left (right). The fitting procedure is described in Section 7.

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Two-particle Bose-Einstein correlations and their Lévy parameters in PbPb collisions at $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV

The CMS collaboration Tumasyan, Armen ; Adam, Wolfgang ; Andrejkovic, Janik Walter ; et al.
Phys.Rev.C 109 (2024) 024914, 2024.
Inspire Record 2670243 DOI 10.17182/hepdata.134676

Two-particle Bose-Einstein momentum correlation functions are studied for charged-hadron pairs in lead-lead collisions at a center-of-mass energy per nucleon pair of $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV. The data sample, containing 4.27 $\times$$10^{9}$ minimum bias events corresponding to an integrated luminosity of 0.607 nb$^{-1}$, was collected by the CMS experiment in 2018. The experimental results are discussed in terms of a Lévy-type source distribution. The parameters of this distribution are extracted as functions of particle pair average transverse mass and collision centrality. These parameters include the Lévy index or shape parameter ($\alpha$), the Lévy scale parameter ($R$), and the correlation strength parameter ($\lambda$). The source shape, characterized by $\alpha$, is found to be neither Cauchy nor Gaussian, implying the need for a full Lévy analysis. Similarly to what was previously found for systems characterized by Gaussian source radii, a hydrodynamical scaling is observed for the Lévy $R$ parameter. The $\lambda$ parameter is studied in terms of the core-halo model.

12 data tables

The correlation function $C_2(q)$ of negatively charged hadron pairs with $1.00<K_{\mathrm{T}}<1.05$ GeV/$c$ in the 10-20% centrality bin.

The double-ratio correlation function $DR(q)$ of negatively charged hadron pairs with $1.30<K_{\mathrm{T}}<1.35$ GeV/$c$ in the 20-30% centrality bin.

The two-particle correlation function of negatively charged hadron pairs with $0.9<K_{\mathrm{T}}<1.3$ GeV/$c$ in the 0-100% centrality range, calculated using MC events with (Reco) and without (Gen) detector reconstruction.

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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.
Phys.Rev.Lett. 132 (2024) 111901, 2024.
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$^{-1}$. Three structures are found, and a model with quantum interference among these structures provides a good description of the data. A new structure is observed with a significance above 5 standard deviations at a mass of 6638 $^{+43}_{-38}$ (stat) $^{+16}_{-31}$ (syst) MeV. Another structure with even higher significance is found at a mass of 6847 $^{+44}_{-28}$ (stat) $^{+48}_{-20}$ (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 4.7 standard deviations, is found at a mass of 7134 $^{+48}_{-25}$ (stat) $^{+41}_{-15}$ (syst) MeV. Results are also reported for a model without interference, which does not fit the data as well and shows mass shifts up to 150 MeV relative to the model with interference.

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


Search for a long-lived spin-0 mediator in $b\to s$ transitions at the Belle II experiment

The Belle-II collaboration Adachi, I. ; Adamczyk, K. ; Aggarwal, L. ; et al.
Phys.Rev.D 108 (2023) L111104, 2023.
Inspire Record 2665757 DOI 10.17182/hepdata.147283

Additional spin-0 particles appear in many extensions of the standard model. We search for long-lived spin-0 particles $S$ in $B$-meson decays mediated by a $b\to s$ quark transition in $e^+e^-$ collisions at the $\Upsilon(4S)$ resonance at the Belle II experiment. Based on a sample corresponding to an integrated luminosity of $189 \mathrm{\,fb}^{-1}$, we observe no evidence for signal. We set model-independent upper limits on the product of branching fractions $\mathrm{Br}(B^0\to K^*(892)^0(\to K^+\pi^-)S)\times \mathrm{Br}(S\to x^+x^-)$ and $\mathrm{Br}(B^+\to K^+S)\times \mathrm{Br}(S\to x^+x^-)$, where $x^+x^-$ indicates $e^+e^-, \mu^+\mu^-, \pi^+\pi^-$, or $K^+K^-$, as functions of $S$ mass and lifetime at the level of $10^{-7}$.

164 data tables

Expected and observed candidates for $\mathcal{B}($$B^+\to K^+S$$) \times$ $\mathcal{B}($$S\to e^+e^-$) as a function of the reduced mediator candidate mass.

Expected and observed candidates for $\mathcal{B}($$B^+\to K^+S$$) \times$ $\mathcal{B}($$S\to \mu^+\mu^-$) as a function of the reduced mediator candidate mass.

Expected and observed candidates for $\mathcal{B}($$B^+\to K^+S$$) \times$ $\mathcal{B}($$S\to \pi^+\pi^-$) as a function of the reduced mediator candidate mass.

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Search for the lepton-flavor violating decay of the Higgs boson and additional Higgs bosons in the e$\mu$ final state in proton-proton collisions at $\sqrt{s}$ = 13 TeV

The CMS collaboration Hayrapetyan, Aram ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
Phys.Rev.D 108 (2023) 072004, 2023.
Inspire Record 2663255 DOI 10.17182/hepdata.139722

A search for the lepton-flavor violating decay of the Higgs boson and potential additional Higgs bosons with a mass in the range 110-160 GeV to an e$^{\pm}\mu^{\mp}$ pair is presented. The search is performed with a proton-proton collision dataset at a center-of-mass energy of 13 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 138 fb$^{-1}$. No excess is observed for the Higgs boson. The observed (expected) upper limit on the e$^{\pm}\mu^{\mp}$ branching fraction for it is determined to be 4.4 (4.7) $\times$ 10$^{-5}$ at 95% confidence level, the most stringent limit set thus far from direct searches. The largest excess of events over the expected background in the full mass range of the search is observed at an e$^{\pm}\mu^{\mp}$ invariant mass of approximately 146 GeV with a local (global) significance of 3.8 (2.8) standard deviations.

23 data tables

Observed (expected) 95% confidence level upper limits on $\mathcal{B}(H \to e \mu)$ for each individual analysis category (as shown in the left axis label) and for the combination of all analysis categories.

Observed (expected) 95% confidence level upper limits on $\sigma(p p \to X \to e \mu)$ as functions of the hypothesised $m_{X}$ assuming the relative SM-like production cross sections of the ggH and VBF production modes.

Observed local $\textit{p}$-values against the background-only hypothesis are shown as a function of the hypothesised $m_{X}$.

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Measurements of the azimuthal anisotropy of prompt and nonprompt charmonia in PbPb collisions at $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV

The CMS collaboration Tumasyan, Armen ; Adam, Wolfgang ; Andrejkovic, Janik Walter ; et al.
JHEP 10 (2023) 115, 2023.
Inspire Record 2663026 DOI 10.17182/hepdata.130962

The second-order ($v_2$) and third-order ($v_3$) Fourier coefficients describing the azimuthal anisotropy of prompt and nonprompt (from b-hadron decays) J/$\psi$, as well as prompt $\psi$(2S) mesons are measured in lead-lead collisions at a center-of-mass energy per nucleon pair of $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV. The analysis uses a data set corresponding to an integrated luminosity of 1.61 nb$^{-1}$ recorded with the CMS detector. The J/$\psi$ and $\psi$(2S) mesons are reconstructed using their dimuon decay channel. The $v_2$ and $v_3$ coefficients are extracted using the scalar product method and studied as functions of meson transverse momentum and collision centrality. The measured $v_2$ values for prompt J/$\psi$ mesons are found to be larger than those for nonprompt J/$\psi$ mesons. The prompt J/$\psi$$v_2$ values at high $p_\mathrm{T}$ are found to be underpredicted by a model incorporating only parton energy loss effects in a quark-gluon plasma medium. Prompt and nonprompt J/$\psi$ meson $v_3$ and prompt $\psi$(2S) $v_2$ and $v_3$ values are also reported for the first time, providing new information about heavy quark interactions in the hot and dense medium created in heavy ion collisions.

9 data tables

The $v_{2}$ values as functions of $p_{\text{T}}$ for prompt and nonprompt J/$\psi$ mesons in the 10–60% centrality range. The results for 3 $< p_{\text{T}} <$ 6.5 and 6.5 $< p_{\text{T}} <$ 50 GeV/c are studied in the rapidity range of 1.6 $< |y| <$ 2.4 and $|y| <$ 2.4, respectively.

The $v_{2}$ values as a function of centrality for prompt and nonprompt J/$\psi$ mesons. The kinematic range is 6.5 $< p_{\text{T}} <$ 50 GeV/c and $|y| <$ 2.4.

The $v_{3}$ values as functions of $p_{\text{T}}$ for prompt and nonprompt J/$\psi$ mesons in the 10–60% centrality range. The results for 3 $< p_{\text{T}} <$ 6.5 and 6.5 $< p_{\text{T}} <$ 50 GeV/c are studied in the rapidity range of 1.6 $< |y| <$ 2.4 and $|y| <$ 2.4, respectively.

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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.