951 research outputs found
Limits on nu_e and anti-nu_e disappearance from Gallium and reactor experiments
The deficit observed in the Gallium radioactive source experiments is
interpreted as a possible indication of the disappearance of electron
neutrinos. In the effective framework of two-neutrino mixing we obtain
and . The compatibility of this result with the data of the Bugey and
Chooz reactor short-baseline antineutrino disappearance experiments is studied.
It is found that the Bugey data present a hint of neutrino oscillations with
and , which is compatible with the Gallium allowed region of the
mixing parameters. This hint persists in the combined analyses of Bugey and
Chooz data, of Gallium and Bugey data, and of Gallium, Bugey, and Chooz data.Comment: 21 pages. Final version to be published in Phys. Rev.
Light sterile neutrino sensitivity of 163Ho experiments
We explore the sensitivity of Ho electron capture experiments to
neutrino masses in the standard framework of three-neutrino mixing and in the
framework of 3+1 neutrino mixing with a sterile neutrino which mixes with the
three standard active neutrinos, as indicated by the anomalies found in
short-baseline neutrino oscillations experiments. We calculate the sensitivity
to neutrino masses and mixing for different values of the energy resolution of
the detectors, of the unresolved pileup fraction and of the total statistics of
events, considering the expected values of these parameters in the two planned
stages of the ECHo project (ECHo-1k and ECHo-1M). We show that an extension of
the ECHo-1M experiment with the possibility to collect events will be
competitive with the KATRIN experiment. This statistics will allow to explore
part of the 3+1 mixing parameter space indicated by the global analysis of
short-baseline neutrino oscillation experiments. In order to cover all the
allowed region, a statistics of about events will be needed.Comment: 11 page
Electromagnetic properties of neutrinos
A short review on electromagnetic properties of neutrinos is presented. In
spite of many efforts in the theoretical and experimental studies of neutrino
electromagnetic properties, they still remain one of the main puzzles related
to neutrinos.Comment: The talk presented by A.Studenikin at the International Conference on
Topics in Astroparticle and Underground Physics, Rome (Italy), July 1-5, 200
Baryon Asymmetry of the Universe without Boltzmann or Kadanoff-Baym
We present a formalism that allows the computation of the baryon asymmetry of
the universe from first principles of statistical physics and quantum field
theory that is applicable to certain types of beyond the Standard Model physics
(such as the neutrino Minimal Standard Model -- MSM) and does not require
the solution of Boltzmann or Kadanoff-Baym equations. The formalism works if a
thermal bath of Standard Model particles is very weakly coupled to a new sector
(sterile neutrinos in the MSM case) that is out-of-equilibrium. The key
point that allows a computation without kinetic equations is that the number of
sterile neutrinos produced during the relevant cosmological period remains
small. In such a case, it is possible to expand the formal solution of the von
Neumann equation perturbatively and obtain a master formula for the lepton
asymmetry expressed in terms of non-equilibrium Wightman functions. The master
formula neatly separates CP-violating contributions from finite temperature
correlation functions and satisfies all three Sakharov conditions. These
correlation functions can then be evaluated perturbatively; the validity of the
perturbative expansion depends on the parameters of the model considered. Here
we choose a toy model (containing only two active and two sterile neutrinos) to
illustrate the use of the formalism, but it could be applied to other models.Comment: 26 pages, 10 figure
Coherence of neutrino flavor mixing in quantum field theory
In the simplistic quantum mechanical picture of flavor mixing, conditions on
the maximum size and minimum coherence time of the source and detector regions
for the observation of interference---as well as the very viability of the
approach---can only be argued in an ad hoc way from principles external to the
formalism itself. To examine these conditions in a more fundamental way, the
quantum field theoretical -matrix approach is employed in this paper,
without the unrealistic assumption of microscopic stationarity. The fully
normalized, time-dependent neutrino flavor mixing event rates presented here
automatically reveal the coherence conditions in a natural, self-contained, and
physically unambiguous way, while quantitatively describing the transition to
their failure.Comment: 12 pages, submitted to Phys. Rev.
Gopi: compiling linear and static channels in go
PTDC/CCI-COM/32166/2017We identify two important features to enhance the design of communication protocols specified in the pi-calculus, that are linear and static channels, and present a compiler, named GoPi, that maps high level specifications into executable Go programs. Channels declared as linear are deadlock-free, while the scope of static channels, which are bound by a hide declaration, does not enlarge at runtime; this is enforced statically by means of type inference, while specifications do not include annotations. Well-behaved processes are transformed into Go code that supports non-deterministic synchronizations and race-freedom. We sketch two main examples involving protection against message forwarding, and forward secrecy, and discuss the features of the tool, and the generated code. We argue that GoPi can support academic activities involving process algebras and formal models, which range from the analysis and testing of concurrent processes for research purposes to teaching formal languages and concurrent systems.publishersversionpublishe
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