Bollettino Settimanale Lunedì 19 gennaio 2015 AULA CONVERSI ORE 16.00 SEMINARIO TEORICO Non local gravity Fabio Briscese (Dipartamento de Fisica, CCEN, Universidade Federal da Paraiba, Cidade Universitaria, Brazil.) In this seminar I will introduce a new nonlocal model of gravitation, the so called superrenormalizable quantum gravity model, and I will review its main properties. In particular I will discuss the power counting renormalizability and some features of the classical solutions. Martedi’ 20 gennaio 2015 SALA DIREZIONE INFN ORE 14.00 SEMINARIO INFN-Fisica particelle elementari Rivelazione di fotoni con MicroPattern Gas Detector (MPGD) S. Dalla Torre (INFN - Sezione di Trieste) La rivelazione di fotoni con rilevatori a gas e' introdotta in chiave storica. I MPGD offrono nuove oppportunita' che permettono di superare alcuni limiti intrinseci degli approcci precedenti. Viene offerta una panoromatica degli sviluppi recenti e delle applicazioni sia nell'ambito della ricerca fondamentale che in campi di interesse sociale. SALA DIREZIONE INFN ORE 16.00 SEMINARIO STRUTTURA DELLA AULA CONVERSI ORE 16.00 MATERIA SEMINARIO GENERALE Screening of charge impurities: an alternative The Top Quark: Yes, it is Large, but is it mechanism for the detection of gases on Essential? graphene and nanotubes Michael E. Peskin Jorge O. Sofo (SLAC, Stanford Unversity) (The Pennsylvania State University) The top quark now well-characterized as the In gas detection with carbon nanotubes or heaviest particle in the particle physicist's Standard graphene, the change in conductivity due to Model. But, still, we do not understand the molecular adsorption has been generally significance of this property. Is the top quark just an attributed to a change in carrier density due to ordinary quark, though somewhat oversized? Does charge transfer. However, these explanation does its heaviness give it a special role in the story of the not take into account several important physical Higgs boson, dark matter, and other open effects. 1) The counter-ions left after the charge questions? Is it the lightest of a set of even more transfer process lower the mobility and might massive particles, lying just over our current compensate the effect of extra carriers. 2) The horizon? Does it represent the climax of our current experimental results are not consistent with story of particle physics, or the beginning of the variations in the ionization potential or electron next one? In this lecture, ! I will review what is affinities of the adsorbates. We proposed an known about the top quark and discuss the alternative explanation based on the screening directions that the study of this quark may take us produced by the molecules on the charge in the future. impurities of the substrate. Given that the scattering with these impurities is the main limiting factor of the conductivity, the change in screening produced by the mol! ecules has a substantial effect on the conductivity. Our model is based on the dielectric function of graphene at the RPA level and the impurity scattering in the first Born approximation. With this model we explain the increase in conductivity and we determine optimum parameters to increase the sensitivity of the devices. Mercoledi’ 21 gennaio 2015 Giovedi’ 22 gennaio 2015 Venerdì 23 gennaio 2015
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