A search for dark matter produced in association with a top quark pair is presented. The search is performed using 19.7 $mathrm{fb^{-1}}$ of proton-proton collisions recorded at a center of mass energy of 8 TeV with the CMS detector at the LHC. The s
ignature investigated is top quark pairs in the semi-leptonic final state plus missing transverse energy. This work focuses in particular on dark matter production through scalar interaction where a proportionality to the quark mass is expected.
The experimental systematic uncertainties associated to the reconstruction and calibration of the objects appearing in top quark final states at the LHC and Tevatron are discussed. The strategies followed in the ATLAS and CMS experiments are compared
in detail for the cases of the jet energy scale and $b$-tagging calibrations, where a categorisation of the associated uncertainty sources as well as the corresponding correlations across experiments has been proposed. The estimate of the non-prompt and fake lepton background to the top quark leptonic channels is also discussed.
A joint measurement is presented of the branching fractions $B^0_stomu^+mu^-$ and $B^0tomu^+mu^-$ in proton-proton collisions at the LHC by the CMS and LHCb experiments. The data samples were collected in 2011 at a centre-of-mass energy of 7 TeV, and
in 2012 at 8 TeV. The combined analysis produces the first observation of the $B^0_stomu^+mu^-$ decay, with a statistical significance exceeding six standard deviations, and the best measurement of its branching fraction so far. Furthermore, evidence for the $B^0tomu^+mu^-$ decay is obtained with a statistical significance of three standard deviations. The branching fraction measurements are statistically compatible with SM predictions and impose stringent constraints on several theories beyond the SM.
The CP-violating weak phase $phi_mathrm{s}$ and the decay width difference $DeltaGamma_{mathrm{s}}$ of $mathrm{B}^{0}_{mathrm{s}}$ mesons are measured by the CMS experiment at the LHC using a data sample of $mathrm{B}^{0}_{mathrm{s}} ! to mathrm{J} /
psi,phi$ decays. The analysed dataset corresponds to an integrated luminosity of about $20~mathrm{fb}^{-1}$ collected in $pp$ collisions at a centre-of-mass energy $sqrt{s} = 8~mathrm{TeV}$. A total of $49,000$ reconstructed $mathrm{B}^{0}_{mathrm{s}}$ decays are used to extract the values $phi_mathrm{s}$ and $DeltaGamma_mathrm{s}$ by performing a time-dependent and flavour-tagged angular analysis of the $mu^+mu^-mathrm{K}^+mathrm{K}^-$ final state.The weak phase is measured to be $phi_mathrm{s} = -0.03 pm 0.11~mathrm{(stat.)} pm 0.03~mathrm{(syst.)}~mathrm{rad}$, and the decay width difference between the $mathrm{B}^{0}_{mathrm{s}}$ mass eigenstates is $DeltaGamma_mathrm{s} = 0.096 pm 0.014~mathrm{(stat.)} pm 0.007~mathrm{(syst.)}~mathrm{ps}^{-1}$.
The latest results from CMS on searches for supersymmetry are presented. Searches involving all-hadronic final states with jets and missing transverse energy, and in final states including one or more isolated leptons are discussed. The results are b
ased on 19.5/fb of LHC proton-proton collisions at sqrt = 8 TeV taken with the CMS detector.
The latest results on searches for stop and sbottom squarks are presented. Searches for direct squark production in a variety of decay channels are reviewed. The results are based on 19.5/fb of LHC proton-proton collisions at sqrt = 8 TeV taken with the CMS detector.
The top quark physics has entered the precision era. The CDF and D0 collaborations are finalizing their legacy results of the properties of the top quark after the shutdown of the Fermilab Tevatron three years ago. The ATLAS and CMS collaborations ha
ve been publishing results from the LHC Run I with 7 TeV and 8 TeV proton-proton collisions, with many more forthcoming. We present a selection of recent results produced by the Tevatron and LHC experiments.
Single top-quark t-channel production is exploited for studies of top quark properties. The analyses include the measurement of the CKM matrix element, $|V_{tb}|$, search for anomalous couplings of the top quark using a Bayesian neural network analys
is, measurement of single top-quark polarization which directly confirms the V-A nature of the $tWb$ production vertex, and the measurement of W-helicity fractions in the phase space sampled by a selection optimized for t-channel single top-quark production, orthogonal to the $toverline{t}$ final states used in traditional measurements of these properties. All measurements are found to be consistent with the standard model predictions.
We review the current status of the cross sections measurement of the top-quark at the LHC and at the Tevatron. Total production cross sections, studies using single top quark events and differential $rm{t}bar{rm t}$ cross sections are discussed. The
associated production of top quark pairs with photons, Z and W bosons, including $rm{t}bar{rm t}$Z and $rm{t}bar{rm t}$W measurements shown for the first time at LHCP2014, are presented.
Measurements involving top quarks provide important tests of QCD. A selected set of top quark measurements in CMS including the strong coupling constant, top quark pole mass, constraints on parton distribution functions, top quark pair differential c
ross sections, ttbar+0 and >0 jet events, top quark mass studied using various kinematic variables in different phase-space regions, and alternative top quark mass measurements is presented. The evolution of expected uncertainties in future LHC runs for the standard and alternative top quark mass measurements is also presented.
