Fully differential NLO predictions for the radiative decay of muons and taus

We present a general purpose Monte Carlo program for the calculation of the radiative muon decay $\mu\to e\,\nu \bar{\nu}\gamma$ and the radiative decays $\tau\to e\, \nu \bar{\nu}\gamma$ and $\tau\to\mu\,\nu \bar{\nu}\gamma$ at next-to-leading order in the Fermi theory. The full dependence on the lepton masses and polarization of the initial-sate lepton are kept. We study the branching ratios for these processes and show that fully-differential next-to-leading order corrections are important for addressing a tension between BaBar's recent measurement of the branching ratio $\mathcal{B}(\tau\to e\, \nu\bar{\nu}\gamma)$ and the Standard Model prediction. In addition, we study various distributions of the process $\mu\to e\,\nu \bar{\nu}\gamma$ and obtain precise predictions for the irreducible background to $\mu\to e \gamma$ searches, tailored to the geometry of the MEG detector.Comment: 14 pages, 5 figures, published versio

Tree Level Unitarity Bounds for the Minimal B-L Model

We have derived the unitarity bounds in the high energy limit for the minimal B-L extension of the Standard Model by analysing the full class of Higgs and would-be Goldstone boson two-to-two scatterings at tree level. Moreover, we have investigated how these limits could vary at some lower critical value of the energy.Comment: 20 pages, 4 figures, 2 tables; 1d figure modified, typos corrected, bibliography augmented; published in PRD after minor adjustmen

The Z' boson of the minimal B-L model at future Linear Colliders in e+e- --> mu+mu-

We study the capabilities of future electron-positron Linear Colliders, with centre-of-mass energy at the TeV scale, in accessing the parameter space of a $Z'$ boson within the minimal $B-L$ model. We carry out a detailed comparison between the discovery regions mapped over a two-dimensional configuration space ($Z'$ mass and coupling) at the Large Hadron Collider and possible future Linear Colliders for the case of di-muon production. As known in the literature for other $Z'$ models, we confirm that leptonic machines, as compared to the CERN hadronic accelerator, display an additional potential in discovering a $Z'$ boson as well as in allowing one to study its properties at a level of precision well beyond that of any of the existing colliders.Comment: 5 pages, proceeding of LC09 (Perugia), published by the Italian Physical Society in the Nuovo Cimento C (Colloquia

Production of Z' and W' via Drell-Yan processes in the 4D Composite Higgs Model at the LHC

We present an analysis of both the Neutral Current (NC) and Charged Current (CC) Drell-Yan processes at the LHC within a 4 Dimensional realization of a Composite Higgs model studying the cross sections and taking into account the possible impact of the extra fermions present in the spectrum.Comment: Conference proceeding, XII IFAE Edition, 3-5 April 2013, Cagliari. 2 pages, 2 figures; v2 typo correcte

Phenomenology of the minimal B-L extension of the Standard Model

We present the Large Hadron Collider (LHC) discovery potential in the $Z'$ and heavy neutrino sectors of a $U(1)_{B-L}$ enlarged Standard Model also encompassing three heavy Majorana neutrinos. This model exhibits novel signatures at the LHC, the most interesting arising from a $Z'$ decay chain involving heavy neutrinos, eventually decaying into leptons and jets. In particular, this signature allows one to measure the $Z'$ and heavy neutrino masses involved. In addition, over a large region of parameter space, the heavy neutrinos are rather long-lived particles producing distinctive displaced vertices that can be seen in the detectors. Lastly, the simultaneous measurement of both the heavy neutrino mass and decay length enables an estimate of the absolute mass of the parent light neutrino. For completeness, we will also compare the LHC and a future Linear Collider (LC) discovery potentials.Comment: 4 pages, no figures. LaTeX. Talk given at "The 2009 Europhysics Conference on High Energy Physics", Krakow, Poland, July 16-22, 200

Influence of synthesis conditions on properties of green-reduced graphene oxide

[EN] Green reduction of graphene oxide (GO) was performed using ascorbic acid (AA) in the presence of poly(sodium 4-styrenesulfonate), which resulted in reduced graphene oxide (PSS-rGO) with excellent solubility and stability in water. Large rGO sheets of 4 mu m(2) area and 1.1-nm thickness were obtained. The measurements showed that noncovalent functionalization with PSS molecules prevented rGO from aggregation. The parameters of graphite oxidation process and AA: GO w/w ratio were evaluated, and the obtained results showed that the properties of the reduced material (PSS-rGO) can be tailored by proper selection and adjustment of these parameters.The authors thank the European Commission for their financial support through the project no. NMP3-SL-2010-246073.Pruna, A.; Pullini, D.; Busquets, D. (2013). Influence of synthesis conditions on properties of green-reduced graphene oxide. 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Orienting coupled quantum rotors by ultrashort laser pulses

We point out that the non-adiabatic orientation of quantum rotors, produced by ultrashort laser pulses, is remarkably enhanced by introducing dipolar interaction between the rotors. This enhanced orientation of quantum rotors is in contrast with the behavior of classical paired rotors, in which dipolar interactions prevent the orientation of the rotors. We demonstrate also that a specially designed sequence of pulses can most efficiently enhances the orientation of quantum paired rotors.Comment: 7 pages, 5 figures, to appear in Phys. Rev.

Higgs Boson in the 4DCHM: LHC phenomenology

Composite Higgs models provide an elegant solution to the hierarchy problem present in the Standard Model (SM) and give an alternative pattern leading to the mechanism of Electro-Weak Symmetry Breaking (EWSB). We present an analysis of the Higgs boson production and decay within a recently proposed realistic realization of this general idea: the 4D Composite Higgs Model (4DCHM). Comparing our results with the latest Large Hadron Collider (LHC) data we show that the 4DCHM could provide an alternative explanation with respect to the SM of the LHC results pointing to the discovery of a Higgs-like particle at 125 GeV.Comment: Conference proceeding, EPS-HEP 2013, 18-24 July 2013, Stockholm. 3 pages, 2 figures, typo correcte