Results are reported from a search for supersymmetric particles in the final state with multiple jets and large missing transverse momentum. The search uses a sample of proton-proton collisions at √ s = 13 TeV collected with the CMS detector in 2016-2018, corresponding to an integrated luminosity of 137 fb −1 , representing essentially the full LHC Run 2 data sample. The analysis is performed in a four-dimensional search region defined in terms of the number of jets, the number of tagged bottom quark jets, the scalar sum of jet transverse momenta, and the magnitude of the vector sum of jet transverse momenta. No significant excess in the event yield is observed relative to the expected background contributions from standard model processes. Limits on the pair production of gluinos and squarks are obtained in the framework of simplified models for supersymmetric particle production and decay processes. Assuming the lightest supersymmetric particle to be a neutralino, lower limits on the gluino mass as large as 2000 to 2310 GeV are obtained at 95% confidence level, while lower limits on the squark mass as large as 1190 to 1630 GeV are obtained, depending on the production scenario.

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A search for physics beyond the standard model in events with at least three charged leptons (electrons or muons) is presented. The data sample corresponds to an integrated luminosity of 137 fb−1 of proton-proton collisions at $$ \sqrt{s} $$ s = 13 TeV, collected with the CMS detector at the LHC in 2016–2018. The two targeted signal processes are pair production of type-III seesaw heavy fermions and production of a light scalar or pseudoscalar boson in association with a pair of top quarks. The heavy fermions may be manifested as an excess of events with large values of leptonic transverse momenta or missing transverse momentum. The light scalars or pseudoscalars may create a localized excess in the dilepton mass spectra. The results exclude heavy fermions of the type-III seesaw model for masses below 880 GeV at 95% confidence level in the scenario of equal branching fractions to each lepton flavor. This is the most restrictive limit on the flavor-democratic scenario of the type-III seesaw model to date. Assuming a Yukawa coupling of unit strength to top quarks, branching fractions of new scalar (pseudoscalar) bosons to dielectrons or dimuons above 0.004 (0.03) and 0.04 (0.03) are excluded at 95% confidence level for masses in the range 15–75 and 108–340 GeV, respectively. These are the first limits in these channels on an extension of the standard model with scalar or pseudoscalar particles.

Measurements are presented of the differential cross sections for Z bosons produced in proton-proton collisions at √ s = 13 TeV and decaying to muons and electrons. The data analyzed were collected in 2016 with the CMS detector at the LHC and correspond to an integrated luminosity of 35.9 fb −1. The measured fiducial inclusive product of cross section and branching fraction agrees with next-to-next-to-leading order quantum chromodynamics calculations. Differential cross sections of the transverse momentum p T , the optimized angular variable φ * η , and the rapidity of lepton pairs are measured. The data are corrected for detector effects and compared to theoretical predictions using fixed order, resummed, and parton shower calculations. The uncertainties of the measured normalized cross sections are smaller than 0.5% for φ * η < 0.5 and for p Z T < 50 GeV.

We report the results of a polarized-2-beta-decay experiment carried out in the Fermilab Proton Center charged-hyperon beam. These results are based on 49 671 observed 2 -+ n e -V decays. The 2-beam had a nominal momentum of 250 GeV/c and was produced by 400-GeV/c protons impinging on a Cu target. At a production angle of 2.5 mrad, the polarization was (23.6f 4.31%. The decay asymmetries of the electron ( a , = -0.519+0.104), neutron ( a , = +0.509+0.102), and antineutrino (a,= -0.230f 0.061) were measured and used to establish sign and approximate magnitude of the axial-vector-to-vector form-factor ratio g , / f , . The form-factor ratios g , / f l / and f 2 / f were determined most sensitively from the neutron and electron center-of-mass spectra, respectively. We obtain 1 g , / f l -0.237g,/f1 =0.327i0.007i0.019 and f , ( O ) / f , ( 0 ) = -0.96 f0.07k0.13, where the stated errors are statistical and systematic, respectively. A general fit that includes the asymmetries and makes the conventional assumption g , =O gives the final value g , ( O ) / f , ( 0 ) = -0.328k0.019. The data are also compatible with positive values for g , / f , combined with corresponding reduced values for g , / f , / .