5,464 research outputs found
Using Wavelets to reject background in Dark Matter experiments
A method based on wavelet techniques has been developed and applied to
background rejection in the data of the IGEX dark matter experiment. The method
is presented and described in some detail to show how it efficiently rejects
events coming from noise and microphonism through a mathematical inspection of
their recorded pulse shape. The result of the application of the method to the
last data of IGEX is presented.Comment: 14 pages, 8 figures. Submitted to Astrop. Phy
Neutron background at the Canfranc Underground Laboratory and its contribution to the IGEX-DM dark matter experiment
A quantitative study of the neutron environment in the Canfranc Underground
Laboratory has been performed. The analysis is based on a complete set of
simulations and, particularly, it is focused on the IGEX-DM dark matter
experiment. The simulations are compared to the IGEX-DM low energy data
obtained with different shielding conditions. The results of the study allow us
to conclude, with respect to the IGEX-DM background, that the main neutron
population, coming from radioactivity from the surrounding rock, is practically
eliminated after the implementation of a suitable neutron shielding. The
remaining neutron background (muon-induced neutrons in the shielding and in the
rock) is substantially below the present background level thanks to the muon
veto system. In addition, the present analysis gives us a further insight on
the effect of neutrons in other current and future experiments at the Canfranc
Underground Laboratory. The comparison of simulations with the body of data
available has allowed to set the flux of neutrons from radioactivity of the
Canfranc rock, (3.82 +- 0.44) x 10^{-6} cm^{-2} s^{-1}, as well as the flux of
muon-induced neutrons in the rock, (1.73 +- 0.22(stat) \+- 0.69(syst)) x
10^{-9} cm^{-2} s^{-1}, or the rate of neutron production by muons in the lead
shielding, (4.8 +- 0.6 (stat) +- 1.9 (syst)) x 10^{-9} cm^{-3} s^{-1}.Comment: 17 pages, 8 figures, elsart document class; final version to appear
in Astroparticle Physic
Unitarization effects in EFT predictions of WZ scattering at the LHC
Effective field theories are an incredibly powerful tool in order to study
and understand the true nature of the symmetry breaking sector dynamics of the
Standard Model. However, they can suffer from some theoretical problems such as
that of unitarity violation. Nevertheless, in order to interpret experimental
data correctly a fully unitary prescription is needed. To this purpose,
unitarization methods are addressed, but each of them leads to a different
(unitary) prediction. Because of this, there is an inherent theoretical
uncertainty in the determination of the effective field theory parameters due
to the choice of one unitarization scheme. In this work, we quantify this
uncertainty assuming a strongly interacting electroweak symmetry breaking
sector, described by the effective electroweak chiral Lagrangian. We focus on
the bosonic part of this effective Lagrangian and choose in particular the WZ
scattering as our main VBS channel to study the sensitivity to new physics at
the LHC. We study the different predictions of various well known unitarization
methods, considering the full coupled system of helicity amplitudes, and
construct the 95\% confidence level exclusion regions for the most relevant
electroweak chiral Lagrangian parameters, given by the two anomalous quartic
gauge couplings and . This provides a consistent analysis of the
different constraints on EChL parameters that can be achieved by using
different unitarization methods in a combined way.Comment: 25 pages, 8 figures (20 plots), this version matches the published
article in Phys. Rev.
First results of the ROSEBUD Dark Matter experiment
Rare Objects SEarch with Bolometers UndergrounD) is an experiment which
attempts to detect low mass Weak Interacting Massive Particles (WIMPs) through
their elastic scattering off Al and O nuclei. It consists of three small
sapphire bolometers (of a total mass of 100 g) with NTD-Ge sensors in a
dilution refrigerator operating at 20 mK in the Canfranc Underground
Laboratory. We report in this paper the results of several runs (of about 10
days each) with successively improved energy thresholds, and the progressive
background reduction obtained by improvement of the radiopurity of the
components and subsequent modifications in the experimental assembly, including
the addition of old lead shields. Mid-term plans and perspectives of the
experiment are also presented.Comment: 14 pages, 8 figures, submitted to Astroparticle Physic
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