The Scuola Normale Superiore di Pisa is a public higher learning institution in Pisa, Italy.The Scuola Normale, together with the University of Pisa and Sant'Anna School of Advanced Studies, is a part of the Pisa University System. It is one of the three officially sanctioned special-statute public universities in Italy, being part of the process of Superior Graduate School in Italy or Scuola Superiore Universitaria. Wikipedia.
Lodone P.,Normal School of Pisa
Journal of High Energy Physics | Year: 2010
Adopting a bottom-up point of view, we make a comparative study of the simplest extensions of the MSSM with extra tree level contributions to the lightest Higgs boson mass. We show to what extent a relatively heavy Higgs boson, up to 200-350 GeV, can be compatible with data and naturalness. The price to pay is that the theory undergoes some change of regime at a relatively low scale. Bounds on these models come from electroweak precision tests and naturalness, which often requires the scale at which the soft terms are generated to be relatively low. © SISSA 2010.
Improta R.,CNR Institute of Biostructure and Bioimaging |
Barone V.,Normal School of Pisa
Angewandte Chemie - International Edition | Year: 2011
The excited states of (dA) 4 oligonucleotides (A=adenine), including the phosphoribose backbone, were studied in water at a fully quantum mechanical level, providing an atomistic description of the main decay paths and a comprehensive interpretation of the experimental data (see picture). After absorption to exciton states delocalized over multiple A bases, the behavior of the excited state is ruled by the interplay of a number of species responsible for different spectral features. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Murphy C.W.,Normal School of Pisa
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015
Predictions are made for the forward-backward and charge asymmetries in bottom-quark pair production at hadron colliders. Tree-level exchanges of electroweak (EW) gauge bosons dominate the Standard Model (SM) contribution to the asymmetry near the Z-pole. The mixed EW-QCD corrections are computed in an approximate way, and are found to be small in magnitude. These SM predictions are consistent with experimental results from CDF, D0, and LHCb. In particular, CDF and LHCb find that the asymmetry in the invariant mass bin containing the Z-pole is larger than in the adjacent bins, as predicted. Several beyond the Standard Model scenarios proposed for the top-quark forward-backward asymmetry, including a 100 GeV axigluon, are disfavored by this combination of SM predictions and measurements. On the other hand, modified Zbb¯ couplings can explain the 2σ discrepancy in the bottom-quark forward-backward asymmetry at LEP1, while being consistent with the results of CDF and LHCb. It is also shown that t-channel W exchange makes a non-negligible contribution to the charm-quark charge asymmetry. © 2015 American Physical Society. © 2015 American Physical Society.
Matsedonskyi O.,Normal School of Pisa
Journal of High Energy Physics | Year: 2015
Abstract: We analyse the interplay of the constraints imposed on flavour-symmetric Composite Higgs models by Naturalness considerations and the constraints derived from Flavour Physics and Electroweak Precision Tests. Our analysis is based on the Effective Field Theory which describes the Higgs as a pseudo-Nambu-Goldstone boson and also includes the composite fermionic resonances. Within this approach one is able to identify the directions in the parameter space where the U(3)-symmetric flavour models can pass the current experimental constraints, without conflicting with the light Higgs mass. We also derive the general features of the U(2)-symmetric models required by the experimental bounds, in case of elementary and totally composite tR. An effect in the Zb¯ coupling, which can potentially allow for sizable deviations in Z → b¯b decay parameters without modifying flavour physics observables, is identified. We also present the analysis of the mixed scenario, where the top quark mass is generated due to Partial Compositeness while the light quark masses are Technicolor-like. © 2015, The Author(s).
Salvio A.,Normal School of Pisa
Journal of High Energy Physics | Year: 2012
We investigate holographic models of superfluids and superconductors in which the gravitational theory includes a dilatonic field. Dilaton extensions are interesting as they allow us to obtain a better description of low temperature condensed matter systems. We focus on asymptotically AdS black hole configurations, which are dual to field theories with conformal ultraviolet behavior. A nonvanishing value of the dilaton breaks scale invariance in the infrared and is therefore compatible with the normal phase being insulating (or a solid in the fluid mechanical interpretation); indeed we find that this is the case at low temperatures and if one appropriately chooses the parameters of the model. Not only the superfluid phase transitions, but also the response to external gauge fields is analyzed. This allows us to study, among other things, the vortex phase and to show that these holographic superconductors are also of Type II. However, at low temperatures they can behave in a qualitatively different way compared to their analogues without the dilaton: the critical magnetic fields and the penetration depth can remain finite in the small T/Tc limit. © SISSA 2012.