11,638 research outputs found
Inverse type II seesaw mechanism and its signature at the LHC and ILC
The advent of the LHC, and the proposal of building future colliders as the
ILC, both programmed to explore new physics at the TeV scale, justifies the
recent interest in studying all kind of seesaw mechanisms whose signature lies
on such energy scale. The natural candidate for this kind of seesaw mechanism
is the inverse one. The conventional inverse seesaw mechanism is implemented in
an arrangement involving six new heavy neutrinos in addition to the three
standard ones. In this paper we develop the inverse seesaw mechanism based on
Higgs triplet model and probe its signature at the LHC and ILC. We argue that
the conjoint analysis of the LHC together with the ILC may confirm the
mechanism and, perhaps, infer the hierarchy of the neutrino masses.Comment: 24 pages, 22 figure
Are Neutron-Rich Elements Produced in the Collapse of Strange Dwarfs ?
The structure of strange dwarfs and that of hybrid stars with same baryonic
number is compared. There is a critical mass (M~0.24M_sun) in the strange dwarf
branch, below which configurations with the same baryonic number in the hybrid
star branch are more stable. If a transition occurs between both branches, the
collapse releases an energy of about of 3x10^{50} erg, mostly under the form of
neutrinos resulting from the conversion of hadronic matter onto strange quark
matter. Only a fraction (~4%) is required to expel the outer neutron-rich
layers. These events may contribute significantly to the chemical yield of
nuclides with A>80 in the Galaxy, if their frequency is of about one per 1500
years.Comment: Accepted for publication in IJMP
Disorder effects at low temperatures in La_{0.7-x}Y_{x}Ca_{0.3}MnO_{3} manganites
With the aim of probing the effect of magnetic disorder in the
low-temperature excitations of manganites, specific-heat measurements were
performed in zero field, and in magnetic fields up to 9 T in polycrystalline
samples of La_{0.7-x}Y_{x}Ca_{0.3}MnO_{3}, with Y concentrations x=0, 0.10, and
0.15. Yttrium doping yielded the appearance of a cluster-glass state, giving
rise to unusual low-temperature behavior of the specific-heat. The main feature
observed in the results is a strong enhancement of the specific-heat linear
term, which is interpreted as a direct consequence of magnetic disorder. The
analysis was further corroborated by resistivity measurements in the same
compounds.Comment: 9 pages, 2 figure
The massive 3-loop operator matrix elements with two masses and the generalized variable flavor number scheme
We report on our latest results in the calculation of the two--mass
contributions to 3--loop operator matrix elements (OMEs). These OMEs are needed
to compute the corresponding contributions to the deep-inealstic scattering
structure functions and to generalize the variable flavor number scheme by
including both charm and bottom quarks. We present the results for the
non-singlet and OMEs, and compare the size of their contribution
relative to the single mass case. Results for the gluonic OME are
given in the physical case, going beyond those presented in a previous
publication where scalar diagrams were computed. We also discuss our recently
published two--mass contribution to the pure singlet OME, and present an
alternative method of calculating the corresponding diagrams.Comment: 20 pages Latex, 5 Figures, different style file
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