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A measurement of the Higgs boson mass and width via its decay to two $Z$bosons is presented. Proton-proton collision data collected by the CMS experiment, corresponding to an integrated luminosity of $138{\mathrm{fb}}^{-1}$at a center-of-mass energy of 13 TeV, is used. The invariant mass distribution of four leptons in the on-shell Higgs boson decay is used to measure its mass and constrain its width. This yields the most precise single measurement of the Higgs boson mass to date, $125.04\pm 0.12\mathrm{GeV}$, and an upper limit on the width ${\mathrm{\Gamma }}_H<330\mathrm{MeV}$at 95% confidence level. A combination of the on- and off-shell Higgs boson production decaying to four leptons is used to determine the Higgs boson width, assuming that no new virtual particles affect the production, a premise that is tested by adding new heavy particles in the gluon fusion loop model. This result is combined with a previous CMS analysis of the off-shell Higgs boson production with decay to two leptons and two neutrinos, giving a measured Higgs boson width of ${3.0}_{-1.5}^{+2.0}\mathrm{MeV}$, in agreement with the standard model prediction of 4.1 MeV. The strength of the off-shell Higgs boson production is also reported. The scenario of no off-shell Higgs boson production is excluded at a confidence level corresponding to 3.8 standard deviations. © 2025 CERN, for the CMS Collaboration2025CERN 

A<sc>bstract</sc> Measurements of fiducial and total inclusive cross sections for W and Z boson production are presented in proton-proton collisions at$$ \sqrt{s} $$ $\sqrt{s}$= 5.02 and 13 TeV. Electron and muon decay modes (ℓ= e orμ) are studied in the data collected with the CMS detector in 2017, in dedicated runs with reduced instantaneous luminosity. The data sets correspond to integrated luminosities of 298 ± 6 pb⁻¹at 5.02 TeV and 206 ± 5 pb⁻¹at 13 TeV. Measured values of the products of the total inclusive cross sections and the branching fractions at 5.02 TeV areσ(pp→W + X)$$ \mathcal{B} $$ $B$(W→ ℓν) = 7300±10 (stat)±60 (syst)±140 (lumi) pb, andσ(pp→Z+X)$$ \mathcal{B} $$ $B$(Z→ ℓ⁺ℓ⁻) = 669±2 (stat)±6 (syst)±13 (lumi) pb for the dilepton invariant mass in the range of 60–120 GeV. The corresponding results at 13 TeV are 20480±10 (stat)±170 (syst)±470 (lumi) pb and 1952±4 (stat)±18 (syst)±45 (lumi) pb. The measured values agree with cross section calculations at next-to-next-to-leading-order in perturbative quantum chromodynamics. Fiducial and total inclusive cross sections, ratios of cross sections of W⁺and W⁻production as well as inclusive W and Z boson production, and ratios of these measurements at 5.02 and 13 TeV are reported. 

Nuclear medium effects on $B^{+}$meson production are studied using the binary-collision scaled cross section ratio between events of different charged-particle multiplicities from proton-lead collisions. Data, collected by the CMS experiment in 2016 at a nucleon-nucleon center-of-mass energy of $\sqrt{s_{\mathrm{NN}}}=8.16\mathrm{TeV}$, corresponding to an integrated luminosity of $175{\mathrm{nb}}^{-1}$, were used. The scaling factors in the ratio are determined using a novel approach based on the $Z\to {\mu }^{-}{\mu }^{+}$cross sections measured in the same events. The scaled ratio for $B^{+}$is consistent with unity for all event multiplicities, putting stringent constraints on nuclear modification for heavy flavor. © 2025 CERN, for the CMS Collaboration2025CERN 

A<sc>bstract</sc> The production cross sections of$$ {\textrm{B}}_{\textrm{s}}^0 $$ $B_s^0$and B⁺mesons are reported in proton-proton (pp) collisions recorded by the CMS experiment at the CERN LHC with a center-of-mass energy of 5.02 TeV. The data sample corresponds to an integrated luminosity of 302 pb⁻¹. The cross sections are based on measurements of the$$ {\textrm{B}}_{\textrm{s}}^0 $$ $B_s^0$→J/ψ(μ⁺μ⁻)ϕ(1020)(K⁺K⁻) and B⁺→J/ψ(μ⁺μ⁻)K⁺decay channels. Results are presented in the transverse momentum (p_T) range 7–50 GeV/cand the rapidity interval |y|<2.4 for the B mesons. The measuredp_T-differential cross sections of B⁺and$$ {\textrm{B}}_{\textrm{s}}^0 $$ $B_s^0$in pp collisions are well described by fixed-order plus next-to-leading logarithm perturbative quantum chromodynamics calculations. Using previous PbPb collision measurements at the same nucleon-nucleon center-of-mass energy, the nuclear modification factors,R_AA, of the B mesons are determined. Forp_T>10 GeV/c, both mesons are found to be suppressed in PbPb collisions (withR_AAvalues significantly below unity), with less suppression observed for the$$ {\textrm{B}}_{\textrm{s}}^0 $$ $B_s^0$mesons. In thisp_Trange, theR_AAvalues for the B⁺mesons are consistent with those for inclusive charged hadrons and D⁰mesons. Below 10 GeV/c, both B⁺and$$ {\textrm{B}}_{\textrm{s}}^0 $$ $B_s^0$are found to be less suppressed than either inclusive charged hadrons or D⁰mesons, with the$$ {\textrm{B}}_{\textrm{s}}^0 $$ $B_s^0$R_AAvalue consistent with unity. TheR_AAvalues found for the B⁺and$$ {\textrm{B}}_{\textrm{s}}^0 $$ $B_s^0$are compared to theoretical calculations, providing constraints on the mechanism of bottom quark energy loss and hadronization in the quark-gluon plasma, the hot and dense matter created in ultrarelativistic heavy ion collisions. 

A search is presented for an extended Higgs sector with two new particles, $X$and $\varphi$, in the process $X\to \varphi \varphi \to \left(\gamma \gamma \right)\left(\gamma \gamma \right)$. Novel neural networks classify events with diphotons that are merged and determine the diphoton masses. The search uses LHC proton-proton collision data at $\sqrt{s}=13\mathrm{TeV}$collected with the CMS detector, corresponding to an integrated luminosity of $138{\mathrm{fb}}^{-1}$. No evidence of such resonances is seen. Upper limits are set on the production cross section for $m_X$between 300 and 3000 GeV and $m_{\varphi }/m_X$between 0.5% and 2.5%, representing the most sensitive search in this channel. © 2025 CERN, for the CMS Collaboration2025CERN