No abstract

Searches for invisible decays of the Higgs boson are presented. The data collected with the CMS detector at the LHC correspond to integrated luminosities of 5.1, 19.7, and 2.3 fb −1 at centre-of-mass energies of 7, 8, and 13 TeV, respectively. The search channels target Higgs boson production via gluon fusion, vector boson fusion, and in association with a vector boson. Upper limits are placed on the branching fraction of the Higgs boson decay to invisible particles, as a function of the assumed production cross sections. The combination of all channels, assuming standard model production, yields an observed (expected) upper limit on the invisible branching fraction of 0.24 (0.23) at the 95% confidence level. The results are also interpreted in the context of Higgs-portal dark matter models. [6,7]. More generally, invisible Higgs boson decays can be realised through interactions between the Higgs boson and dark matter (DM) [8]. In Higgs-portal models [9][10][11][12], the Higgs boson acts as a mediator between SM and DM particles allowing for direct production of DM at the LHC. Furthermore, cosmological models proposing that the Higgs boson played a central role in the evolution of the early universe motivate the study of the relationship between the Higgs boson and DM [13, 14].Direct searches for invisible decays of the Higgs boson increase the sensitivity to the invisible Higgs boson width beyond the indirect constraints. The typical signature at the LHC is a large missing transverse momentum recoiling against a distinctive visible system. Previous searches by the ATLAS and CMS Collaborations have targeted Higgs boson production in association with a vector boson (VH, where V denotes W or Z) [15][16][17] or with jets consistent with a vector boson fusion (VBF, via qq → qqH) topology [17, 18]. A combination of direct searches for invisible Higgs boson decays in qqH and VH production, by the ATLAS Collaboration, yields an upper limit of 0.25 on the Higgs boson invisible branching fraction, B(H → inv), at the 95% confidence level [19]. Additionally, searches by the ATLAS Collaboration for DM in events with missing transverse momentum accompanied by jets have been interpreted in the context of Higgs boson production via gluon fusion and subsequent decay to invisible particles [20].In this paper, results from a combination of searches for invisible decays of the Higgs boson using data collected during 2011, 2012, and 2015 are presented. The searches target the qqH, VH, and ggH production modes. The searches for the VH production mode include searches targeting ZH production, in which the Z boson decays to a pair of leptons (either e + e − or µ + µ − ) or bb, and searches for both the ZH and WH production modes, in which the W or Z boson decays to light-flavour jets. Additional sensitivity is achieved in this analysis by including a search targeting gluon fusion production where the Higgs boson is produced accompanied by a gluon jet (gg → gH). The diagrams for the qqH, VH, and ggH Higgs boson production pr...

Results are presented of a search for heavy stable charged particles produced in proton-proton collisions at ffiffi ffi s p ¼ 13 TeV using a data sample corresponding to an integrated luminosity of 2.5 fb −1 collected in 2015 with the CMS detector at the CERN LHC. The search is conducted using signatures of anomalously high energy deposits in the silicon tracker and long time-of-flight measurements by the muon system. The data are consistent with the expected background, and upper limits are set on the cross sections for production of long-lived gluinos, top squarks, tau sleptons, and leptonlike long-lived fermions. These upper limits are equivalently expressed as lower limits on the masses of new states; the limits for gluinos, ranging up to 1610 GeV, are the most stringent to date. Limits on the cross sections for direct pair production of long-lived tau sleptons are also determined.

The angular distributions and the differential branching fraction of the decay B 0 → K * (892) 0 µ + µ − are studied using data corresponding to an integrated luminosity of 20.5 fb −1 collected with the CMS detector at the LHC in pp collisions at √ s = 8 TeV. From 1430 signal decays, the forward-backward asymmetry of the muons, the K * (892) 0 longitudinal polarization fraction, and the differential branching fraction are determined as a function of the dimuon invariant mass squared. The measurements are among the most precise to date and are in good agreement with standard model predictions.

Results on two-particle angular correlations for charged particles produced in pp collisions at a centerof-mass energy of 13 TeV are presented. The data were taken with the CMS detector at the LHC and correspond to an integrated luminosity of about 270 nb −1 . The correlations are studied over a broad range of pseudorapidity (jηj < 2.4) and over the full azimuth (ϕ) as a function of charged particle multiplicity and transverse momentum (p T ). In high-multiplicity events, a long-range (jΔηj > 2.0), near-side (Δϕ ≈ 0) structure emerges in the two-particle Δη-Δϕ correlation functions. The magnitude of the correlation exhibits a pronounced maximum in the range 1.0 < p T < 2.0 GeV=c and an approximately linear increase with the charged particle multiplicity, with an overall correlation strength similar to that found in earlier pp data at ffiffi ffi s p ¼ 7 TeV. The present measurement extends the study of near-side long-range correlations up to charged particle multiplicities N ch ∼ 180, a region so far unexplored in pp collisions. The observed longrange correlations are compared to those seen in pp, pPb, and PbPb collisions at lower collision energies.