Search results for "Computer Science Application"
showing 10 items of 3998 documents
Implications of new generations on neutrino masses
2011
We explore the possible implications that new families, that are being searched for at the LHC, would have on neutrino masses. In particular, we have explored the possibility that the smallness of the observed neutrino masses is naturally understood in a modified version of the Standard Model (SM) with complete extra generations of fermions, i.e., that have right-handed neutrinos, in which neutrino masses are generated at two loops. With one extra family it is not possible to fit the observed spectrum of masses and mixings. However, the radiative mass generated provides an important constraint in these kind of models, so the neutrino masses do not exceed their cosmological bound. Within the…
Double beta decay and the quest for Majorana neutrinos
2020
Abstract The observation of neutrinoless double beta (0νββ) decay remains crucial for understanding lepton number violation. The inverse half-life for 0νββ-decay is given by the product of a phase space factor (PSF), a nuclear matrix element (NME), which both rely on theoretical description, and a function f containing the physics beyond the standard model. Phase space factors and nuclear matrix elements have been evaluated, or are under evaluation, systematically for all processes of interest. The nuclear matrix elements have been calculated within the framework of the microscopic interacting boson model (IBM-2), and phase space factors have been evaluated using exact Dirac electron wave f…
New limits on neutrino magnetic moments from low energy neutrino data
2016
Here we give a brief review on the current bounds on the general Majorana transition neutrino magnetic moments (TNMM) which cover also the conventional neutrino magnetic moments (NMM). Leptonic CP phases play a key role in constraining TNMMs. While the Borexino experiment is the most sensitive to the TNMM magnitudes, one needs complementary information from reactor and accelerator experiments in order to probe the complex CP phases.
Mass of the bottom quark from Upsilon(1S) at NNNLO: an update
2016
We update our perturbative determination of MSbar bottom quark mass mb(mb), by including the recently obtained four-loop coefficient in the relation between the pole and MSbar mass. First the renormalon subtracted (RS or RS') mass is determined from the known mass of the Upsilon(1S) meson, where we use the renormalon residue Nm obtained from the asymptotic behavior of the coefficient of the 3-loop static singlet potential. MSbar mass is then obtained using the 4-loop renormalon-free relation between the RS (RS') and MSbar mass. We argue that the effects of the charm quark mass are accounted for by effectively using Nf=3 in the mass relations. The extracted value is mb(mb) = 4222(40) MeV, wh…
Time reversal violation for entangled neutral mesons
2013
A direct evidence for Time Reversal Violation (TRV) means an experiment that, considered by itself, clearly shows TRV independent of, and unconnected to, the results for CP Violation. No existing result before the recent BABAR experiment with entangled neutral B mesons had demonstrated TRV in this sense. There is a unique solution for the test of TRV with unstable particles thanks to the Einstein-Podolsky-Rosen (EPR) Entanglement between the two neutral mesons in B, and φ, Factories. The two quantum effects of the decays as filtering measurements of the meson states and the transfer of information of the first decay to the still living partner allow performing a genuine TRV asymmetry with t…
Novel T-violation observable open to any decay channel at meson factories
2015
Two genuine Quantum phenomena: Entanglement and Filtering Measurement are at the origin of the first direct observation of Time-Reversal-Violation in the time evolution of the B neutral meson system by BaBar. The used meson transitions are directly connected to semileptonic and CP-eigenstate decay channels. We analyse the possibility of extending the observable asymmetries to more decay channels. We propose an alternative T-Violation Asymmetry in the meson factories which allows its opening to any pair of decay channels. The new asymmetry needs also the measurement of the time dependent total survival probability of the initial tagged states. By combining several asymmetries these total sur…
Flavoured leptogenesis: A successful thermal leptogenesis withN1mass below 108GeV
2009
We prove that taking correctly into account the lepton flavour dependence of the CP asymmetries and washout processes, it is possible to obtain successful thermal leptogenesis from the decays of the second right-handed neutrino. The asymmetries in the muon and tau-flavour channels are then not erased by the inverse decays of the lightest right-handed neutrino, N1. In this way, we reopen the possibility of 'thermal leptogenesis' in models with a strong hierarchy in the right-handed Majorana masses that is typically the case in models with up-quark–neutrino Yukawa unification.
Three-flavor neutrino oscillations and beyond
2020
Abstract In this work we summarize the current status of global neutrino oscillation analyses in the three-neutrino framework. We first describe the different data samples included in the global fit, emphasizing the role of each of them in constraining a given set of parameters. Next, we discuss the main improvements obtained thanks to the consideration of the latest experimental data. The status of the yet-unknown parameters, such as the true neutrino mass ordering, the Dirac CP-violating phase and the octant of the atmospheric mixing angle is also commented. Finally, we discuss some scenarios where the measurement of the reactor mixing angle or the CP violation phase could be significantl…
Selected topics on Hadrons in Nuclei
2011
In this talk we report on selected topics on hadrons in nuclei. The first topic is the renormalization of the width of the $\Lambda(1520)$ in a nuclear medium. This is followed by a short update of the situation of the $\omega$ in the medium. The investigation of the properties of $\bar{K}$ in the nuclear medium from the study of the $(K_{flight},p)$ reaction is also addressed, as well as properties of X,Y,Z charmed and hidden charm resonances in a nuclear medium. Finally we address the novel issue of multimeson states.
Clusters and the quasi-dynamical symmetry
2008
The possible role of the quasi-dynamical symmetry in nuclear clusterization is discussed. Two particular examples are considered: i) the phases and phase-transitions of some algebraic cluster models, and ii) the clusterization in heavy nuclei. The interrelation of exotic (superdeformed, hyperdeformed) nuclear shapes and cluster-configurations are also investigated both for light, and for heavy nuclei, based on the dynamical and quasi-dynamical SU(3) symmetries, respectively.