Multiple Parton Interactions Studies at CMS

This paper summarizes the Multiple Parton Interactions studies in CMS, focusing on the already performed low pT QCD measurements up to highest centre of mass energies of 7 TeV and discussing the plans for the direct measurement of the multiple high-pT scatterings. The underlying event in pp interactions is studied measuring the charged multiplicity density and the charged energy density in the transverse region, which is defined considering the azimuthal distance of the reconstructed tracks with respect to the leading track-jet of the event, defined from tracks according to a jet clustering algorithms. In addition, we present the measurement of the underlying event using the jet-area/median approach, demonstrating its sensitivity to different underlying event scenarios. Observations in the central region are complemented by the mea- surement of the energy flow in the forward direction for minimum bias and central di-jet events. We compare our underlying event and forward results with the predictions from different Monte Carlo event generators and tunes, aiming to best parametrize the multiple parton interaction energy de- pendence starting from the Monte Carlo tunes developed to best fit the charged particle spectra measured at central rapidities. Finally we discuss the strategy to directly measure the multiple particle interactions rate focusing on the topologies with two hard scatterings in the same event

Underlying Events and Diffraction Studies at the LHC

The potential of the LHC experiments to study the underlying events and diffractive in proton-proton collisions at sqrt{s} =14 TeV is described. The underlying event is studied by examining charged particles in the region transverse to jets and in the central region of Drell-Yan muon-pair production. The diffractive program includes studies of QCD, low-x structure of the proton, and central exclusive production of SM and MSSM Higgs. The measurement of the scattered protons at appropriate locations along the beam-line is especially useful at high instantaneous luminosities

O bairro, a fachada, os moradores, os estudantes : Interações por meio da arte e da educação

O presente trabalho traz minha experiência como arte-educadora do Projeto Pintura na Fachada com educandos da EMEF Padre José Narciso Vieira Ehrenberg, Marcos em Campinas - SP. O objetivo do projeto é reunir os alunos da escola para que através da apropriaçao da linguagem artística da pintura mural, possam expressar suas questoes em relaçao ao bairro. O projeto consiste em colocar os alunos em contato com os moradores do bairro, para investigar os múltiplos olhares dos moradores antigos para o Jardim Sao Marcos. A partir dessa investigaçao e de conversas informais e entrevistas, os alunos identificaram os elementos imagéticos presente no discurso dos moradores, para reproduzi-los na pintura mural. A pintura mural é feita na fachada das casas dos moradores entrevistados em que o morador escolhe entre uma gama de imagens produzidas pelos alunos, a imagem que para ele representa o bairro ou a imagem que ele quer estampada na fachada de sua casa. A pintura mural nas fachadas das casas baseia-se na linguagem das intervençoes urbanas como instrumento crítico e investigativo das relaçoes sociais da comunidade loca

Bow-Tie Cavity for Terahertz Radiation

We report on the development, testing, and performance analysis of a bow-tie resonant cavity for terahertz (THz) radiation, injected with a continuous-wave 2.55 THz quantum cascade laser. The bow-tie cavity employs a wire-grid polarizer as input/output coupler and a pair of copper spherical mirrors coated with an unprotected 500 nm thick gold layer. The improvements with respect to previous setups have led to a measured finesse value F=123, and a quality factor Q = 5.1x10^5. The resonator performances and the relevant parameters are theoretically predicted and discussed, and a comparison among simulated and experimental spectra is given

Slow Light amplification in a non-inverted gain medium

We investigate the propagation of a coherent probe light pulse through a three-level atomic medium (in the $\Lambda$--configuration) in the presence of a pump laser under the conditions for gain without inversion. When the carrier frequency of the probe pulse and the pump laser are in a Raman configuration, we show that it is possible to amplify a slow propagating pulse. We also analyze the regime in which the probe pulse is slightly detuned from resonance where we observe anomalous light propagation.Comment: 7 pages, 10 figures. To be published in Europhysics Letter

Tuning Monte Carlo Generators: The Perugia Tunes

We present 9 new tunes of the pT-ordered shower and underlying-event model in PYTHIA 6.4. These "Perugia" tunes update and supersede the older "S0" family. The data sets used to constrain the models include hadronic Z0 decays at LEP, Tevatron minimum-bias data at 630, 1800, and 1960 GeV, Tevatron Drell-Yan data at 1800 and 1960 GeV, and SPS min-bias data at 200, 546, and 900 GeV. In addition to the central parameter set, called "Perugia 0", we introduce a set of 8 related "Perugia Variations" that attempt to systematically explore soft, hard, parton density, and colour structure variations in the theoretical parameters. Based on these variations, a best-guess prediction of the charged track multiplicity in inelastic, nondiffractive minimum-bias events at the LHC is made. Note that these tunes can only be used with PYTHIA 6, not with PYTHIA 8. Note: this report was updated in March 2011 with a new set of variations, collectively labeled "Perugia 2011", that are optimized for matching applications and which also take into account some lessons from the early LHC data. In order not to break the original text, these are described separately in Appendix B. Note 2: a subsequent "Perugia 2012" update is described in Appendix C.Comment: 46 page