64,743 research outputs found
Regularity of the Hardy-Littlewood maximal operator on block decreasing functions
We study the Hardy-Littlewood maximal operator defined via an unconditional
norm, acting on block decreasing functions. We show that the uncentered maximal
operator maps block decreasing functions of special bounded variation to
functions with integrable distributional derivatives, thus improving their
regularity. In the special case of the maximal operator defined by the
l_infty-norm, that is, by averaging over cubes, the result extends to block
decreasing functions of bounded variation, not necessarily special.Comment: 26 page
Vector triplets at the LHC
Several popular extensions of the Standard Model predict extra vector fields
that transform as triplets under the gauge group SU(2)_L. These multiplets
contain Z' and W' bosons, with masses and couplings related by gauge
invariance. We review some model-independent results about these new vector
bosons, with emphasis on di-lepton and lepton-plus-missing-energy signals at
the LHC.Comment: LaTex 5 pages. Talk by M. Perez-Victoria at LHCP 2013, Barcelona,
Spain, May 13-18, 2013. New reference adde
Constraining decaying dark matter with neutron stars
The amount of decaying dark matter, accumulated in the central regions in
neutron stars together with the energy deposition rate from decays, may set a
limit on the neutron star survival rate against transitions to more compact
objects provided nuclear matter is not the ultimate stable state of matter and
that dark matter indeed is unstable. More generally, this limit sets
constraints on the dark matter particle decay time, . We find that
in the range of uncertainties intrinsic to such a scenario, masses or and lifetimes s and
s can be excluded in the bosonic or fermionic
decay cases, respectively, in an optimistic estimate, while more
conservatively, it decreases by a factor . We
discuss the validity under which these results may improve with other current
constraints.Comment: 6 pages, 1 figure, matches published versio
Revising the Solution of the Neutrino Oscillation Parameter Degeneracies at Neutrino Factories
In the context of neutrino factories, we review the solution of the
degeneracies in the neutrino oscillation parameters. In particular, we have set
limits to in order to accomplish the unambiguous
determination of and . We have performed two different
analysis. In the first, at a baseline of 3000 km, we simulate a measurement of
the channels , and
, combined with their respective conjugate ones,
with a muon energy of 50 GeV and a running time of five years. In the second,
we merge the simulated data obtained at L=3000 km with the measurement of
channel at 7250 km, the so called 'magic baseline'. In both
cases, we have studied the impact of varying the detector
efficiency-mass product, , at 3000 km,
keeping unchanged the detector mass and its efficiency. At L=3000 km,
we found the existance of degenerate zones, that corresponds to values of
, which are equal or almost equal to the true ones. These zones
are extremely difficult to discard, even when we increase the number of events.
However, in the second scenario, this difficulty is overcomed, demostrating the
relevance of the 'magic baseline'. From this scenario, the best limits of
, reached at , for ,
0.975 and 0.99 are: 0.008, 0.015 and 0.045, respectively, obtained at
, and considering ,
which is five times the initial efficiency-mass combination.Comment: 40 pages, 18 figures; added references, corrected typos, updated Eq
(15c
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