Signatures of doubly charged Higgs in the SU(3)(L) circle times U(1)(N) model at the CERN LHC

The scalar sector of the simplest version of the 3-3-1 electroweak model is constructed with three Higgs triplets only. We show that a relation involving two of the constants of the model, two vacuum expectation values of the neutral scalars, and the mass of the doubly charged Higgs boson leads to important information concerning the signals of this scalar particle.

Extra dimensions at the CERN LHC via mini-black holes: Effective Kerr-Newman brane-world effects

We solve Einstein equations on the brane to derive the exact form of the brane-world-corrected perturbations in Kerr-Newman singularities, using Randall-Sundrum and Arkani-Hamed-Dimopoulos-Dvali (ADD) models. It is a consequence of such models that Kerr-Newman mini-black holes can be produced in LHC. We use this approach to derive a normalized correction for the Schwarzschild Myers-Perry radius of a static (4+n)-dimensional mini-black hole, using more realistic approaches arising from Kerr-Newman mini-black hole analysis. Besides, we prove that there are four Kerr-Newman black hole horizons in the brane-world scenario we use, although only the outer horizon is relevant in the physical measurable processes. Parton cross sections in LHC and Hawking temperature are also investigated as functions of Planck mass (in the LHC range 1-10 TeV), mini-black hole mass, and the number of large extra dimensions in brane-world large extra-dimensional scenarios. In this case a more realistic brane-effect-corrected formalism can achieve more precisely the effective extra-dimensional Planck mass and the number of large extra dimensions-in the Arkani-Hamed-Dimopoulos-Dvali model-or the size of the warped extra dimension-in Randall-Sundrum formalism.

Robust CERN LHC Higgs boson search in weak boson fusion

We demonstrate that a CERN LHC Higgs boson search in weak boson fusion production with subsequent decay to weak boson pairs is robust against extensions of the standard model or minimal supersymmetric standard model involving a large number of Higgs doublets. We also show that the transverse mass distribution provides unambiguous discrimination of a continuum Higgs signal from the standard model.

Observing Higgs dark matter at the CERN LHC

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

New signature for color octet pseudoscalars at the CERN LHC

Color octet (pseudo)scalars, if they exist, will be copiously produced at the CERN Large Hadron Collider (LHC). However, their detection can become a very challenging task. In particular, if their decay into a pair of top quarks is kinematically forbidden, the main decay channel would be into two jets, with a very large background. In this brief report we explore the possibility of using anomaly-induced decays of the color octet pseudoscalars into gauge bosons to find them at the LHC.

Observation of Z decays to four leptons with the CMS detector at the LHC

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Signal and backgrounds for the single production of scalar and vector leptoquarks at the CERN LHC

We perform a detailed analysis of the potentiality of the CERN Large Hadron Collider to study the single production of leptoquarks via pp→e±q→ leptoquark →e± q, with e± generated by the splitting of photons radiated by the protons. Working with the most general SU(2)L⊗U( 1 )Y invariant effective Lagrangian for scalar and vector leptoquarks, we analyze in detail the leptoquark signals and backgrounds that lead to a final state containing an e± and a hard jet with approximately balanced transverse momenta. Our results indicate that the LHC will be able to discover leptoquarks with masses up to 2-3 TeV, depending on their type, for Yukawa couplings of the order of the electromagnetic one.

Strongly interacting vector bosons at the CERN LHC: Quartic anomalous couplings

We analyze the potential of the CERN Large Hadron Collider to study anomalous quartic vector-boson interactions through the production of vector-boson pairs accompanied by jets. In the framework of SU(2) L⊗U(1) Y chiral Lagrangians, we examine all effective operators of order p 4 that lead to new four-gauge-boson interactions but do not alter trilinear vertices. In our analyses, we perform the full tree-level calculation of the processes leading to two jets plus vector-boson pairs, W +W -,W ±W ±,W ±Z, or ZZ, taking properly into account the interference between the standard model and the anomalous contributions. We obtain the bounds that can be placed on the anomalous quartic interactions and we study the strategies to distinguish the possible new couplings. ©1998 The American Physical Society.

Signal and backgrounds for leptoquarks at the CERN LHC. II. Vector leptoquarks

We perform a detailed analyses of the CERN Large Hadron Collider (LHC) capability to discover first generation vector leptoquarks through their pair production. We study the leptoquark signals and backgrounds that give rise to final states containing a pair e+e- and jets. Our results show that the LHC will be able to discover vector leptoquarks with masses up to 1.8-2.3 TeV depending on their couplings to fermions and gluons. ©1999 The American Physical Society.

Diphoton signals for large extra dimensions at the Fermilab Tevatron and CERN LHC

We analyze the potentiality of hadron colliders to search for large extra dimensions via the production of photon pairs. The virtual exchange of Kaluza-Klein gravitons can significantly enhance this process provided the quantum gravity scale (MS) is in the TeV range. We studied in detail the subprocesses qq̄→γγ and gg → γγ taking into account the complete standard model and graviton contributions as well as the unitarity constraints. We show that the Fermilab Tevatron run II will be able to probe MS up to 1.5-1.9 TeV at 2σ level, while the CERN LHC can extend this search to 5.3-6.7 TeV, depending on the number of extra dimensions. ©2000 The American Physical Society.

Measurement of the charge ratio of atmospheric muons with the CMS detector

We present a measurement of the ratio of positive to negative muon fluxes from cosmic ray interactions in the atmosphere, using data collected by the CMS detector both at ground level and in the underground experimental cavern at the CERN LHC. Muons were detected in the momentum range from 5 GeV/. c to 1 TeV/. c. The surface flux ratio is measured to be 1.2766±0.0032(stat.)±0.0032(syst.), independent of the muon momentum, below 100 GeV/. c. This is the most precise measurement to date. At higher momenta the data are consistent with an increase of the charge ratio, in agreement with cosmic ray shower models and compatible with previous measurements by deep-underground experiments. © 2010.

First measurement of the underlying event activity at the LHC with √ = 0.9 TeV

A measurement of the underlying activity in scattering processes with pT scale in the GeV region is performed in proton-proton collisions at √ = 0.9 TeV, using data collected by the CMS experiment at the LHC. Charged particle production is studied with reference to the direction of a leading object, either a charged particle or a set of charged particles forming a jet. Predictions of several QCD-inspired models as implemented in PYTHIA are compared, after full detector simulation, to the data. The models generally predict too little production of charged particles with pseudorapidity {pipe}η{pipe} < 2, pT > 0.5 GeV/c, and azimuthal direction transverse to that of the leading object. © 2010 CERN for benefit of the CMS collaboration.

Observation of long-range, near-side angular correlations in pPb collisions at the LHC

Results on two-particle angular correlations for charged particles emitted in pPb collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV are presented. The analysis uses two million collisions collected with the CMS detector at the LHC. The correlations are studied over a broad range of pseudorapidity, η, and full azimuth, φ, as a function of charged particle multiplicity and particle transverse momentum, pT. In high-multiplicity events, a long-range (2<|δη|<4), near-side (δφ≈0) structure emerges in the two-particle δη-δφ correlation functions. This is the first observation of such correlations in proton-nucleus collisions, resembling the ridge-like correlations seen in high-multiplicity pp collisions at s=7 TeV and in AA collisions over a broad range of center-of-mass energies. The correlation strength exhibits a pronounced maximum in the range of pT=1-1.5 GeV/c and an approximately linear increase with charged particle multiplicity for high-multiplicity events. These observations are qualitatively similar to those in pp collisions when selecting the same observed particle multiplicity, while the overall strength of the correlations is significantly larger in pPb collisions. © 2012 CERN.

Search for new physics in final states with a lepton and missing transverse energy in pp collisions at the LHC

This Letter describes the search for an enhanced production rate of events with a charged lepton and a neutrino in high-energy pp collisions at the LHC. The analysis uses data collected with the CMS detector, with an integrated luminosity of 5.0 fb-1 at √s=7 TeV, and a further 3.7 fb -1 at √s=8 TeV. No evidence is found for an excess. The results are interpreted in terms of limits on a heavy charged gauge boson (W ′) in the sequential standard model, a split universal extra dimension model, and contact interactions in the helicity-nonconserving model. For the last, values of the binding energy below 10.5 (8.8) TeV in the electron (muon) channel are excluded at a 95% confidence level. Interpreting the ℓν final state in terms of a heavy W′ with standard model couplings, masses below 2.90 TeV are excluded. © 2013 CERN.

Measurements of differential jet cross sections in proton-proton collisions at √s=7 TeV with the CMS detector

Measurements of inclusive jet and dijet production cross sections are presented. Data from LHC proton-proton collisions at √s=7 TeV, corresponding to 5.0 fb-1 of integrated luminosity, have been collected with the CMS detector. Jets are reconstructed up to rapidity 2.5, transverse momentum 2 TeV, and dijet invariant mass 5 TeV, using the anti-k T clustering algorithm with distance parameter R=0.7. The measured cross sections are corrected for detector effects and compared to perturbative QCD predictions at next-to-leading order, using five sets of parton distribution functions. © 2013 CERN.