46,363 research outputs found
Model-checking Quantitative Alternating-time Temporal Logic on One-counter Game Models
We consider quantitative extensions of the alternating-time temporal logics
ATL/ATLs called quantitative alternating-time temporal logics (QATL/QATLs) in
which the value of a counter can be compared to constants using equality,
inequality and modulo constraints. We interpret these logics in one-counter
game models which are infinite duration games played on finite control graphs
where each transition can increase or decrease the value of an unbounded
counter. That is, the state-space of these games are, generally, infinite. We
consider the model-checking problem of the logics QATL and QATLs on one-counter
game models with VASS semantics for which we develop algorithms and provide
matching lower bounds. Our algorithms are based on reductions of the
model-checking problems to model-checking games. This approach makes it quite
simple for us to deal with extensions of the logical languages as well as the
infinite state spaces. The framework generalizes on one hand qualitative
problems such as ATL/ATLs model-checking of finite-state systems,
model-checking of the branching-time temporal logics CTL and CTLs on
one-counter processes and the realizability problem of LTL specifications. On
the other hand the model-checking problem for QATL/QATLs generalizes
quantitative problems such as the fixed-initial credit problem for energy games
(in the case of QATL) and energy parity games (in the case of QATLs). Our
results are positive as we show that the generalizations are not too costly
with respect to complexity. As a byproduct we obtain new results on the
complexity of model-checking CTLs in one-counter processes and show that
deciding the winner in one-counter games with LTL objectives is
2ExpSpace-complete.Comment: 22 pages, 12 figure
Non-equilibrium effects on particle freeze-out in the early universe
We investigate the possible effects that deviations from kinetic equilibrium
can have on massive particles as they decouple from chemical equilibrium.
Different methods of solving the Boltzmann equation yield significantly
different relic number densities of such particles. General considerations
concerning the Dirac or Majorana structure of the particles are discussed. It
is shown that non-equilibrium effects are small for particles decoupling while
strongly non-relativistic, as will be the case for most cold dark matter
candidates.Comment: 9 pages REVTEX, to appear in New Astronom
Results of the SDHCAL technological prototype
The SDHCAL technological prototype that has been completed in 2012 was
exposed to beams of pions and electrons of different energies at the CERN SPS
for a total time period of 5 weeks. The data has been analyzed within the
CALICE collaboration. Preliminary results indicate that a highly granular
hadronic calorimeter conceived for PFA application is also a powerful tool to
separate pions from electrons. The SDHCAL provides also a very good resolution
of hadronic showers energy measurement. The use of multi-threshold readout mode
shows a clear improvement of the resolution at energies exceeding 30 GeV with
respect to the binary readout mode. Simulations of the pion interactions in the
SDHCAL are presented and new ideas to improve on the energy resolution using
the topology of hadronic showers are mentioned.Comment: Talk presented at the International Workshop on Future Linear
Colliders (LCWS13), Tokyo, Japan, 11-15 November 201
Neutrino physics from Cosmology
In recent years precision cosmology has become an increasingly powerful probe
of particle physics. Perhaps the prime example of this is the very stringent
cosmological upper bound on the neutrino mass. However, other aspects of
neutrino physics, such as their decoupling history and possible non-standard
interactions, can also be probed using observations of cosmic structure. Here,
I review the current status of cosmological bounds on neutrino properties and
discuss the potential of future observations, for example by the recently
approved EUCLID mission, to precisely measure neutrino properties.Comment: 8 pages, 2 figures, to appear in the proceedings of Pontecorvo100 -
Symposium in honour of Bruno Pontecorv
Cosmological bounds on masses of neutrinos and other thermal relics
With the advent of precision data, cosmology has become an extremely powerful
tool for probing particle physics. The prime example of this is the
cosmological bound on light neutrino masses. Here I review the current status
of cosmological neutrino mass bounds as well as the various uncertainties
involved in deriving them. From WMAP, SDSS, and Lyman-alpha forest data an
upper bound on the sum of neutrino masses of 0.65 eV (95% C.L.) can be derived
with any assumptions about bias. I also present new limits on other light,
thermally produced particles. For example, a hypothetical new Majorana fermion
decoupling around the electroweak phase transition must have m < 5 eV.Comment: 10 pages, 3 figures, to appear in SeeSaw '25 proceedings, references
update
Neutrino cosmology - an update
Present cosmological observations yield an upper bound on the neutrino mass
which is significantly stronger than laboratory bounds. However, the exact
value of the cosmological bound is model dependent and therefore less robust.
Here, I review the current status of cosmological neutrino mass bounds and also
discuss implications for sterile neutrinos and LSND in particular.Comment: Invited talk at Thinking, observing, and mining the universe,
Sorrento, Italy (22-27 September 2003
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