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A search for fermionic top quark partners T of charge 2=3 is presented. The search is carried out in proton-proton collisions corresponding to an integrated luminosity of 19.7 fb −1 collected at a center-ofmass energy of ffiffi ffi s p ¼ 8 TeV with the CMS detector at the LHC. The T quarks are assumed to be produced strongly in pairs and can decay into tH, tZ, and bW. The search is performed in five exclusive channels: a single-lepton channel, a multilepton channel, two all-hadronic channels optimized either for the bW or the tH decay, and one channel in which the Higgs boson decays into two photons. The results are found to be compatible with the standard model expectations in all the investigated final states. A statistical combination of these results is performed and lower limits on the T quark mass are set. Depending on the branching fractions, lower mass limits between 720 and 920 GeV at 95% confidence level are found. These are among the strongest limits on vectorlike T quarks obtained to date.

A search is presented for the production of both first-and second-generation scalar leptoquarks with a final state of either two electrons and one jet or two muons and one jet. The search is based on a data sample of proton-proton collisions at center-of-mass energy ffiffi ffi s p ¼ 8 TeV recorded with the CMS detector and corresponding to an integrated luminosity of 19.6 fb −1 . Upper limits are set on both the first-and secondgeneration leptoquark production cross sections as functions of the leptoquark mass and the leptoquark couplings to a lepton and a quark. Results are compared with theoretical predictions to obtain lower limits on the leptoquark mass. At 95% confidence level, single production of first-generation leptoquarks with a coupling and branching fraction of 1.0 is excluded for masses below 1730 GeV, and second-generation leptoquarks with a coupling and branching fraction of 1.0 is excluded for masses below 530 GeV. These are the best overall limits on the production of first-generation leptoquarks to date.

A search for dark matter and unparticle production at the LHC has been performed using events containing two charged leptons (electrons or muons), consistent with the decay of a Z boson, and large missing transverse momentum. This study is based on data collected with the CMS detector in 2015, corresponding to an integrated luminosity of 2.3 fb −1 of proton-proton collisions at the LHC, at a center-of-mass energy of 13 TeV. No excess over the standard model expectation is observed. Compared to previous searches in this topology, which exclusively relied on effective field theories, the results are interpreted in terms of a simplified model of dark matter production for both vector and axial vector couplings between a mediator and dark matter particles. The first study of this class of models using CMS data at √ s = 13 TeV is presented. Additionally, effective field theories of dark matter and unparticle production are used to interpret the data.

A search for compositeness of electrons and muons is presented using a data sample of proton-proton collisions at a center-of-mass energy of √ s = 8 TeV collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 19.7 fb −1 . Excited leptons ( * ) produced via contact interactions in conjunction with a standard model lepton are considered, and a search is made for their gauge decay modes. The decays considered are * → γ and * → Z, which give final states of two leptons and a photon or, depending on the Z-boson decay mode, four leptons or two leptons and two jets. The number of events observed in data is consistent with the standard model prediction. Exclusion limits are set on the excited lepton mass, and the compositeness scale Λ. For the case M * = Λ the existence of excited electrons (muons) is excluded up to masses of 2.45 (2.47) TeV at 95% confidence level. Neutral current decays of excited leptons are considered for the first time, and limits are extended to include the possibility that the weight factors f and f , which determine the couplings between standard model leptons and excited leptons via gauge mediated interactions, have opposite sign. A Details of the final selection 29The CMS collaboration 35-1 - JHEP03(2016)1251 IntroductionThe standard model (SM) of particle physics describes the observed phenomena very successfully, however it provides no explanation for the three generations of the fermion families. Attempts to explain the observed hierarchy have led to a class of models postulating that quarks and leptons may be composite objects of fundamental constituents [1][2][3][4][5][6][7][8][9]. The fundamental constituents are bound by an asymptotically free gauge interaction that becomes strong at a characteristic scale Λ. Compositeness models predict the existence of excited states of quarks (q * ) and leptons ( * ) at the characteristic scale of the new binding interaction. Since these excited fermions couple to the ordinary SM fermions, they could be produced via contact interactions (CI) in collider experiments, with subsequent decay to ordinary fermions through the emission of a W/Z/γ boson, or via CI to other fermions. Searches at LEP [10][11][12][13], HERA [14], and the Tevatron [15][16][17][18] have found no evidence for excited leptons. At the Large Hadron Collider (LHC) at CERN, previous searches performed by the CMS [19] and the ATLAS collaborations [20] have also found no evidence of excited leptons, obtaining a lower limit on the mass M * < 2.2 TeV for the case M * = Λ.In this paper, a search for excited leptons (e * and µ * ) is presented, using a data sample of pp collisions at a center-of-mass energy √ s = 8 TeV collected with the CMS detector at the LHC in 2012 and corresponding to an integrated luminosity of 19.7 ± 0.5 fb −1 [21].We consider the production of an excited lepton in association with an oppositely charged lepton of the same flavor, with subsequent radiative decays ( * → γ) or neutral current decays ( * → Z). Theory and mod...