University of Milano-Bicocca

About: University of Milano-Bicocca is a education organization based out in Milan, Italy. It is known for research contribution in the topics: Population & Blood pressure. The organization has 8972 authors who have published 22322 publications receiving 620484 citations. The organization is also known as: Università degli Studi di Milano-Bicocca & Universita degli Studi di Milano-Bicocca.

First observation of the decay B+ → π+μ+μ−

Abstract: A discovery of the rare decay $B^{+} \rightarrow \pi^{+} \mu^{+} \mu^{-}$ is presented. This decay is observed for the first time, with 5.2 $\sigma$ significance. The observation is made using $pp$ collision data, corresponding to an integrated luminosity of 1.0 fb$^{-1}$, collected with the LHCb detector. The measured branching fraction is (2.3 $\pm$ 0.6 (stat.) $\pm$ 0.1 (syst.))$\times 10^{-8}$, and the ratio of the $B^{+} \rightarrow \pi^{+} \mu^{+} \mu^{-}$ and $B^{+} \rightarrow \K^{+} \mu^{+} \mu^{-}$ branching fractions is measured to be 0.053 $\pm$ 0.014 (stat.) $\pm$ 0.001 (syst.).

The impact of tobacco use and body mass index on the length of stay in hospital and the risk of post-operative complications among patients undergoing total hip replacement

Abstract: We carried out a retrospective cohort study of 3309 patients undergoing primary total hip replacement to examine the impact of tobacco use and body mass index on the length of stay in hospital and the risk of short term post-operative complications. Heavy tobacco use was associated with an increased risk of systemic post-operative complications (p = 0.004). Previous and current smokers had a 43% and 56% increased risk of systemic complications, respectively, when compared with non-smokers. In heavy smokers, the risk increased by 121%. A high body mass index was significantly associated with an increased mean length of stay in hospital of between 4.7% and 7%. The risk of systemic complications was increased by 58% in the obese. Smoking and body mass index were not significantly related to the development of local complications. Greater efforts should be taken to reduce the impact of preventable life style factors, such as smoking and high body mass index, on the post-operative course of total hip replacement.

Search for a charged Higgs boson in pp collisions at s√=8 TeV

Abstract: A search for a charged Higgs boson is performed with a data sample corresponding to an integrated luminosity of 19.7 +/- 0.5 fb(-1) collected with the CMS detector in proton-proton collisions at root s = 8,TeV. The charged Higgs boson is searched for in top quark decays for m(H +/-) t(b)H-+/- for m(H +/-) > m(t) - m(b). The H-+/- -> tau(+/-)nu(tau) and H-+/- -> tb decay modes in the final states tau(h)+jets, mu tau(h), l+jets, and ll' (l =e, mu) are considered in the search. No signal is observed and 95% confidence level upper limits are set on the charged Higgs boson production. A model-independent upper limit on the product branching fraction B(t -> H(+/-)b) B(H-+/- -> tau(+/-)nu(tau)) = 1.2-0.15% is obtained in the mass range m(H +/-) = 80-160 GeV, while the upper limit on the cross section times branching fraction sigma(pp -> t(b)H-+/-) B(H-+/- -> tau(+/-)nu(tau)) = 0.38-0.025 pb is set in the mass range m(H)+ = 180-600 GeV. Here, sigma(pp -> t(b)H-+/-) stands for the cross section sum sigma(pp -> (t) over bar H+) + sigma(pp -> t (b) over bar H-). Assuming B(t -> H(+/-)b) = 1, an upper limit on sigma(pp -> t(b)H-+/-) of 2.0-0.13 pb is set for m(H +/-) = 180-600 GeV. The combination of all considered decay modes and final states is used to set exclusion limits in the m(H +/-)-tan beta parameter space in different MSSM benchmark scenarios.

Observation of electroweak production of same-sign W boson pairs in the two jet and two same-sign lepton final state in proton-proton collisions at s√= 13 TeV

Abstract: The first observation of electroweak production of same-sign W boson pairs in proton-proton collisions is reported The data sample corresponds to an integrated luminosity of 359 fb^(−1) collected at a center-of-mass energy of 13 TeV with the CMS detector at the LHC Events are selected by requiring exactly two leptons (electrons or muons) of the same charge, moderate missing transverse momentum, and two jets with a large rapidity separation and a large dijet mass The observed significance of the signal is 55 standard deviations, where a significance of 57 standard deviations is expected based on the standard model The ratio of measured event yields to that expected from the standard model at leading order is 090 ± 022 A cross section measurement in a fiducial region is reported Bounds are given on the structure of quartic vector boson interactions in the framework of dimension-8 effective field theory operators and on the production of doubly charged Higgs bosons

A plane wave virtual element method for the Helmholtz problem

Abstract: We introduce and analyze a virtual element method (VEM) for the Helmholtz problem with approximating spaces made of products of low order VEM functions and plane waves. We restrict ourselves to the 2D Helmholtz equation with impedance boundary conditions on the whole domain boundary. The main ingredients of the plane wave VEM scheme are: (i) a low order VEM space whose basis functions, which are associated to the mesh vertices, are not explicitly computed in the element interiors; (ii) a proper local projection operator onto the plane wave space; (iii) an approximate stabilization term. A convergence result for the h -version of the method is proved, and numerical results testing its performance on general polygonal meshes are presented.