14 research outputs found
Lepton mixing and the charged-lepton mass ratios
We construct a class of renormalizable models for lepton mixing that generate
predictions given in terms of the charged-lepton mass ratios. We show that one
of those models leads, when one takes into account the known experimental
values, to almost maximal CP-breaking phases and to almost maximal neutrinoless
double-beta decay. We study in detail the scalar potential of the models,
especially the bounds imposed by unitarity on the values of the quartic
couplings.Comment: 39 pages, 9 figures; revised version addressed the criticism of the
editor, matches now the published versio
Quantum SU(3) Skyrme model with noncanonical embedded SO(3) soliton
The new ansatz which is the SO(3) group soliton was defined for the SU(3)
Skyrme model. The model is considered in noncanonical bases for the state vectors. A complete canonical quantization of the model
have been investigated in the collective coordinate formalism for the
fundamental SU(3) representation of the unitary field. The independent quantum
variables manifold cover all the eight dimensions SU(3) group manifold due to
the new ansatz. The explicit expressions of the Lagrangian and Hamiltonian
densities are derived for this modified quantum skyrmion.Comment: 8 RevTex4 pages, no figure
Noncanonicaly Embedded Rational Map Soliton in Quantum SU(3) Skyrme Model
The quantum Skyrme model is considered in non canonical bases SU(3) > SO(3)
for the state vectors. A rational map ansatz is used to describe the soliton
with the topological number bigger than one. The canonical quantization of the
Lagrangian generates in Hamiltonian five different "moments of inertia" and
negative quantum mass corrections, which can stabilize the quantum soliton
solution. Explicit expressions of the quantum Lagrangian and the Hamiltonian
are derived for this model soliton.Comment: 11 RevTex4 pages, no figure
The three- and four-Higgs couplings in the general two-Higgs-doublet model
We apply the unitarity bounds and the bounded-from-below (BFB) bounds to the
most general scalar potential of the two-Higgs-doublet model (2HDM). We do this
in the Higgs basis, i.e. in the basis for the scalar doublets where only one
doublet has vacuum expectation value. In this way we obtain bounds on the
scalar masses and couplings that are valid for all 2HDMs. We compare those
bounds to the analogous bounds that we have obtained for other simple
extensions of the Standard Model (SM), namely the 2HDM extended by one scalar
singlet and the extension of the SM through two scalar singlets.Comment: 43 pages, 17 figures. In version 2 added new references. Version 3
has many modifications, including modified figures and conclusions, and also
three new appendices. Version 4 matches published versio
Scotogenic model for co-bimaximal mixing
We present a scotogenic model, i.e. a one-loop neutrino mass model with dark
right-handed neutrino gauge singlets and one inert dark scalar gauge doublet
, which has symmetries that lead to co-bimaximal mixing, i.e. to an
atmospheric mixing angle and to a -violating phase
, while the mixing angle remains arbitrary.
The symmetries consist of softly broken lepton numbers (), a non-standard symmetry, and three symmetries. We
indicate two possibilities for extending the model to the quark sector. Since
the model has, besides , three scalar gauge doublets, we perform a
thorough discussion of its scalar sector. We demonstrate that it can
accommodate a Standard Model-like scalar with mass , with
all the other charged and neutral scalars having much higher masses.Comment: v2 - 23 pages, 5 figures, minor changes requested by refere
Quasi-free (p,pN) scattering of light neutron-rich nuclei around N = 14
Background: For many years, quasifree scattering reactions in direct kinematics have been extensively used to study the structure of stable nuclei, demonstrating the potential of this approach. The RB3 collaboration has performed a pilot experiment to study quasifree scattering reactions in inverse kinematics for a stable C12 beam. The results from that experiment constitute the first quasifree scattering results in inverse and complete kinematics. This technique has lately been extended to exotic beams to investigate the evolution of shell structure, which has attracted much interest due to changes in shell structure if the number of protons or neutrons is varied. Purpose: In this work we investigate for the first time the quasifree scattering reactions (p,pn) and (p,2p) simultaneously for the same projectile in inverse and complete kinematics for radioactive beams with the aim to study the evolution of single-particle properties from N=14 to N=15. Method: The structure of the projectiles O23, O22, and N21 has been studied simultaneously via (p,pn) and (p,2p) quasifree knockout reactions in complete inverse kinematics, allowing the investigation of proton and neutron structure at the same time. The experimental data were collected at the R3B-LAND setup at GSI at beam energies of around 400 MeV/u. Two key observables have been studied to shed light on the structure of those nuclei: the inclusive cross sections and the corresponding momentum distributions. Conclusions: The knockout reactions (p,pn) and (p,2p) with radioactive beams in inverse kinematics have provided important and complementary information for the study of shell evolution and structure. For the (p,pn) channels, indications of a change in the structure of these nuclei moving from N=14 to N=15 have been observed, i.e., from the 0d5/2 shell to the 1s1/2. This supports previous observations of a subshell closure at N=14 for neutron-rich oxygen isotopes and its weakening for the nitrogen isotopes
The Spectrum of the Baryon Masses in a Self-consistent SU(3) Quantum Skyrme Model
The semiclassical SU(3) Skyrme model is traditionally considered as describing a rigid quantum rotator with the profile function being fixed by the classical solution of the corresponding SU(2) Skyrme model. In contrast, we go beyond the classical profile function by quantizing the SU(3) Skyrme model canonically. The quantization of the model is performed in terms of the collective coordinate formalism and leads to the establishment of purely quantum corrections of the model. These new corrections are of fundamental importance. They are crucial in obtaining stable quantum solitons of the quantum SU(3) Skyrme model, thus making the model self-consistent and not dependent on the classical solution of the SU(2) case. We show that such a treatment of the model leads to a family of stable quantum solitons that describe the baryon octet and decuplet and reproduce their masses in a qualitative agreement with the empirical values