Publications (258)475.45 Total impact

Dataset: 1s2.00370269391909986main
 [Show abstract] [Hide abstract]
ABSTRACT: We study the constraints that electroweak precision data can impose, after the discovery of the Higgs boson by the LHC, on neutrinophilic twoHiggsdoublet models which comprise one extra $SU(2)\times U(1)$ doublet and a new symmetry, namely a spontaneously broken $\mathbb{Z}_2$ or a softly broken global $U(1)$. In these models the extra Higgs doublet, via its very small vacuum expectation value, is the sole responsible for neutrino masses. We find that the model with a $\mathbb{Z}_2$ symmetry is basically ruled out by electroweak precision data, even if the model is slightly extended to include extra righthanded neutrinos, due to the presence of a very light scalar. While the other model is still perfectly viable, the parameter space is considerably constrained by current data, specially by the $T$ parameter. In particular, the new charged and neutral scalars must have very similar masses.  [Show abstract] [Hide abstract]
ABSTRACT: In composite Higgs models the pseudoNambuGoldstone Boson (pNGB) nature of the Higgs field is an interesting alternative for explaning the smallness of the electroweak scale with respect to the beyond the Standard Model scale. In nonminimal models additional pNGB states are present and can be a Dark Matter (DM) candidate, if there is an approximate symmetry suppressing their decay. Here we assume that the low energy effective theory (for scales much below the compositeness scale) corresponds to the Standard Model with a pNGB Higgs doublet and a pNGB DM multiplet. We derive general effective DM Lagrangians for several possible DM representations (under the SM gauge group), including the singlet, doublet and triplet cases. Within this framework we discuss how the DM observables (relic abundance, direct and indirect detection) constrain the dimension6 operators induced by the strong sector assuming that DM behaves as a Weakly Interacting Particle (WIMP) and that the relic abundance is settled through the freezeout mechanism. We also apply our general results to two specific cosets: $SO(6)/SO(5)$ and $SO(6)/SO(4) \times SO(2)$, which contain a singlet and doublet DM candidate, respectively. In particular we show that if compositeness is a solution to the little hierarchy problem, representations larger than the triplet are strongly disfavored. Furthermore, we find that composite models can have viable DM candidates with much smaller direct detection crosssections than their noncomposite counterparts, making DM detection much more challenging.Journal of High Energy Physics 01/2015; 2015(6). DOI:10.1007/JHEP06(2015)154 · 6.22 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We discuss possible interpretations of the 37 high energy neutrino events observed by the IceCube experiment in the South Pole. We examine the possibility to explain the observed neutrino spectrum exclusively by the decays of a heavy longlived particle of mass in the PeV range. We compare this with the standard scenario, namely, a single powerlaw spectrum related to neutrinos produced by astrophysical sources and a viable hybrid situation where the spectrum is a product of two components: a powerlaw and the longlived particle decays. We present a simple extension of the Standard Model that could account for the heavy particle decays that are needed in order to explain the data. We show that the current data equally supports all above scenarios and try to evaluate the exposure needed in order to falsify them in the future.Journal of High Energy Physics 11/2014; 2015(2). DOI:10.1007/JHEP02(2015)189 · 6.22 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We discuss the potential of a neutrino detector based on liquid scintilator which could be constructed at the ANDES underground laboratory for the observations of neutrinos coming from a galactic supernova and decay of radioactive elements in the Earth interior.10/2013; DOI:10.1063/1.4826789 
Article: The Physics of Neutrinos
[Show abstract] [Hide abstract]
ABSTRACT: These lecture notes are based on a course given at Institut de Physique Th\'eorique of CEA/Saclay in January/February 2013.  [Show abstract] [Hide abstract]
ABSTRACT: We discuss how the lepton CP phase can be constrained by accelerator and reactor measurements in an era without dedicated experiments for CP violation search. To characterize globally the sensitivity to the CP phase \delta_{CP}, we introduce a new measure, the CP exclusion fraction, which quantifies what fraction of the \delta_{CP} space can be excluded at a given input values of \theta_{23} and \delta_{CP}. Using the measure we study the CP sensitivity which may be possessed by the accelerator experiments T2K and NOvA. We show that, if the mass hierarchy is known, T2K and NOvA alone may exclude, respectively, about 50%60% and 40%50% of the \delta_{CP} space at 90% CL by 10 years running, provided that a considerable fraction of beam time is devoted to the antineutrino run. The synergy between T2K and NOvA is remarkable, leading to the determination of the mass hierarchy through CP sensitivity at the same CL.Journal of High Energy Physics 07/2013; 2014(5). DOI:10.1007/JHEP05(2014)109 · 6.22 Impact Factor 
Article: Revisiting the Triangulation Method for Pointing to Supernova and Failed Supernova with Neutrinos
[Show abstract] [Hide abstract]
ABSTRACT: In view of the advent of largescale neutrino detectors such as IceCube, the future HyperKamiokande and the ones proposed for the Laguna project in Europe, we reexamine the determination of the directional position of a Galactic supernova by means of its neutrinos using the triangulation method. We study the dependence of the pointing accuracy on the arrival time resolution of supernova neutrinos at different detectors. For a failed supernova, we expect better results due to the abrupt termination of the neutrino emission which allows one to measure the arrival time with higher precision. We found that for the time resolution of $\pm$ 2 (4) ms, the supernova can be located with a precision of $\sim$ 5 (10)$^\circ$ on the declination and of $\sim$ 8 (15)$^\circ$ on the right ascension angle, if we combine the observations from detectors at four different sites.Physical review D: Particles and fields 04/2013; 88(8). DOI:10.1103/PhysRevD.88.085010 · 4.86 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We analyze the neutrino mass matrix entries and their correlations in a probabilistic fashion, constructing probability distribution functions using the latest results from neutrino oscillation fits. Two cases are considered: the standard three neutrino scenario as well as the inclusion of a new sterile neutrino that potentially explains the reactor and gallium anomalies. We discuss the current limits and future perspectives on the mass matrix elements that can be useful for model building.Journal of High Energy Physics 02/2013; 2013(6). DOI:10.1007/JHEP06(2013)097 · 6.22 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We analyse the interplay between the Higgs to diphoton rate and electroweak precision measurements constraints in extensions of the Standard Model with new uncolored charged fermions that do not mix with the ordinary ones. We also compute the pair production cross sections for the lightest fermion and compare them with current bounds.Journal of High Energy Physics 11/2012; 2012(11). DOI:10.1007/JHEP11(2012)085 · 6.22 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We analyze the behavior of Higgs to diphoton rate and Higgs gluongluon production cross section in minimal extensions of the Standard Model comprising new colored vectorlike fermions that do not mix with the ordinary ones. We compare these information with constraints coming from electroweak precision measurements. We compute pair production cross sections for the lightest fermion and discuss the LHC bounds. Finally, we study the phenomenology of possible quarkonium states composed by these new colored fermions.Journal of High Energy Physics 09/2012; 2013(2). DOI:10.1007/JHEP02(2013)086 · 6.22 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We present an alternative explanation to the reactor antineutrino anomaly through neutrino oscillation induced by the presence of a large flat extra dimension with a size in the submicrometer range. We also show that the solution is consistent with the other existing oscillation data.Journal of Physics Conference Series 07/2012; 375(4). DOI:10.1088/17426596/375/1/042047  [Show abstract] [Hide abstract]
ABSTRACT: We discuss the potential of a liquid scintillator neutrino detector of about 3 kilotons located in the proposed first deep underground laboratory in the Southern Hemisphere, ANDES, to measure geoneutrinos and neutrinos from a stellar corecollapse.Journal of Physics Conference Series 07/2012; 375(4). DOI:10.1088/17426596/375/1/042062  [Show abstract] [Hide abstract]
ABSTRACT: The construction of the Agua Negra tunnels that will link Argentina and Chile under the Andes, the world longest mountain range, opens the possibility to build the first deep underground labo ratory in the Southern Hemisphere. This laboratory has the acronym ANDES (Agua Negra Deep Experiment Site) and its overburden could be as large as \sim 1.7 km of rock, or 4500 mwe, providing an excellent low background environment to study physics of rare events like the ones induced by neutrinos and/or dark matter. In this paper we investigate the physics potential of a few kiloton size liquid scintillator detector, which could be constructed in the ANDES laboratory as one of its possible scientific programs. In particular, we evaluate the impact of such a detector for the studies of geoneutrinos and galactic supernova neutrinos assuming a fiducial volume of 3 kilotons as a reference size. We emphasize the complementary roles of such a detector to the ones in the Northern Hemisphere neutrino facilities through some advantages due to its geographical location.Physical review D: Particles and fields 07/2012; 86(12). DOI:10.1103/PhysRevD.86.125001 · 4.86 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We analyse the interplay between the Higgs to diphoton rate and electroweak precision measurements contraints in extensions of the Standard Model with new uncolored charged fermions that do not mix with the ordinary ones. We also compute the pair production cross sections for the lightest fermion and compare them with current bounds.  [Show abstract] [Hide abstract]
ABSTRACT: We discuss the effects of quantum decoherence for neutrino oscillations in the weak coupling limit and review some experimental bounds. 1. Motivations We all know that within the framework of ordinary quantum mechanics, isolated pure states can never evolve to mixed ones. However, as argued in [1], an analysis about the final fate of a black hole can lead us to introduce the possibility that such evolution takes place. In this picture, quantum fluctuations of the gravitational field, which in turn can be viewed as microblack holes, may lead to the loss of the quantum coherence also in a microscopic level. If pure states can really evolve to incoherent mixtures, quantum mechanics should be modified in some way. Introducing a phenomenological modification in the Liouville equation for the density operator of a quantum system, Ellis et al. [2] showed that the decoherence effects can be effectively implemented. On the other hand, the subdynamics of any open system interacting with a “reservoir” can develop dissipation, and consequently, show an irreversible dynamics. However, this point of view presents no violation of the quantum theory at all [3]. The time evolution of an open system can be described by the so called quantum dynamics semigroups [4] as well as by the master equation formalism [5]. The former is a very general treatment to PrHEP hep2001  [Show abstract] [Hide abstract]
ABSTRACT: If the neutrino analogue of the Mössbauer effect, namely, recoiless emission and resonant capture of neutrinos is realized, one can study neutrino oscillations with much shorter baselines and smaller source/detector size when compared to conventional experiments. In this work, we discuss the potential of such a Mössbauer neutrino oscillation experiment to probe nonstandard neutrino properties coming from some new physics beyond the standard model. We investigate four scenarios for such new physics that modify the standard oscillation pattern. We consider the existence of a light sterile neutrino that can mix with ¯ ν e , the existence of a KaluzaKlein tower of sterile neutrinos that can mix with the flavor neutrinos in a model with large flat extra dimensions, neutrino oscillations with nonstandard quantum decoherence and mass varying neutrinos, and discuss to which extent one can constrain these scenarios. We also discuss the impact of such new physics on the determination of the standard oscillation parameters.Journal of High Energy Physics 01/2012; 11(11). DOI:10.1007/JHEP11(2011)136 · 6.22 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: In the framework of gauged flavour symmetries, new fermions in parity symmetric representations of the standard model are generically needed for the compensation of mixed anomalies. The key point is that their masses are also protected by flavour symmetries and some of them are expected to lie way below the flavour symmetry breaking scale(s), which has to occur many orders of magnitude above the electroweak scale to be compatible with the available data from flavour changing neutral currents and CP violation experiments. We argue that, actually, some of these fermions would plausibly get masses within the LHC range. If they are taken to be heavy quarks and leptons, in (bi)fundamental representations of the standard model symmetries, their mixings with the light ones are strongly constrained to be very small by electroweak precision data. The alternative chosen here is to exactly forbid such mixings by breaking of flavour symmetries into an exact discrete symmetry, the socalled protonhexality, primarily suggested to avoid proton decay. As a consequence of the large value needed for the flavour breaking scale, those heavy particles are longlived and rather appropriate for the current and future searches at the LHC for quasistable hadrons and leptons. In fact, the LHC experiments have already started to look for them.Journal of High Energy Physics 12/2011; 2012(2). DOI:10.1007/JHEP02(2012)123 · 6.22 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: 91 {+} 2% of Boron solar neutrinos observed by SNO are mass eigenstates.Nuclear Physics B  Proceedings Supplements 12/2011; 221. DOI:10.1016/j.nuclphysbps.2011.10.034 · 0.88 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: The lepton mixing angle theta_13, the only unknown angle in the standard threeflavor neutrino mixing scheme, is finally measured by the recent reactor and accelerator neutrino experiments. We perform a combined analysis of the data coming from T2K, MINOS, Double Chooz, Daya Bay and RENO experiments and find sin^2 2theta_13 = 0.096 \pm 0.013 (\pm 0.040) at 1 sigma (3 sigma) CL and that the hypothesis theta_13 = 0 is now rejected at a significance level of 7.7 sigma. We also discuss the near future expectation on the precision of the theta_13 determination by using expected data from these ongoing experiments.Journal of High Energy Physics 11/2011; 2012(5). DOI:10.1007/JHEP05(2012)023 · 6.22 Impact Factor
Publication Stats
2k  Citations  
475.45  Total Impact Points  
Top Journals
Institutions

1992–2013

University of São Paulo
 São Carlos Institute of Physics
San Paulo, São Paulo, Brazil 
Università degli Studi di Trieste
Trst, Friuli Venezia Giulia, Italy


2008

University of Campinas
 Instituto de Física "Gleb Wataghin" (IFGW)
Conceição de Campinas, São Paulo, Brazil


2003

University of California, Santa Barbara
 Kavli Institute for Theoretical Physics
Santa Barbara, California, United States


1992–1995

University of Milan
Milano, Lombardy, Italy


1991

University of Udine
Udine, Friuli Venezia Giulia, Italy


1990

University of Padova
Padua, Veneto, Italy
