3,263 research outputs found
Seasonal variations of the rate of multiple-muons in the Gran Sasso underground laboratory
It is well known that the rate of cosmic ray muons depends on the atmospheric
temperature, and that for events with a single muon the peak of the rate is in
summer, in underground laboratories in the northern hemisphere. In 2015 the
MINOS experiment, in USA, found that, for small distances between the
multiple-muons, the rate of multiple-muons peaks in the winter and that the
amplitude of the modulation is smaller than in the case of a single muon. I
have done a re-analysis of data of the past MACRO experiment. The result is
that under Gran Sasso the rate of multiple-muons at small distances peaks in
the summer. This difference with MINOS could be explained by differences in the
atmospheric temperature due to latitude. This results could be of interest for
dark matter experiments looking to dark matter seasonal modulation due to the
Earth's motion.Comment: presented to the RICAP 2016 conferenc
Search for a possible space-time correlation between high energy neutrinos and -ray bursts
We look for space-time correlations between 2233 gamma-bursts in the Batse Catalogs and 894 upward-going muons produced by neutrino interactions in the rock below or inside MACRO. Considering a search cone of 10 degrees around GRB directions and a time window of 200 s we find 0 events to be compared to 0.035 expected background events due to atmospheric neutrinos. The corresponding upper limit (90% c.l.) is 0.87 * 10^-9 cm^-2 upward-going muons per average burst
New distributed offline processing scheme at Belle
The offline processing of the data collected by the Belle detector has been
recently upgraded to cope with the excellent performance of the KEKB
accelerator. The 127/fb of data (120 TB on tape) collected between autumn 2003
and summer 2004 has been processed in 2 months, thanks to the high speed and
stability of the new, distributed processing scheme. We present here this new
processing scheme and its performance.Comment: 4 pages, 8 figures, uses CHEP2004.cl
Atmospheric Neutrinos
The results of experiments on atmospheric neutrinos are summarized, with the
important exception of Superkamiokande. The main emphasis is given to the
Soudan-2 and MACRO experiments. Both experiments observe atmospheric neutrino
anomalies in agreement with nu_mu-->> nu_tau oscillations with maximum mixing.
The nu_mu-->> nu_sterile oscillation is disfavored by the MACRO experiment.Comment: To be published in the proceedings of TAUP99 Conference College de
France - Paris 6-10 September 1999 11 pages 12 figure
Quark nuggets search using 2350 Kg gravitational waves aluminum bar detectors
The gravitational wave resonant detectors can be used as detectors of quark
nuggets, like nuclearites (nuclear matter with a strange quark). This search
has been carried out using data from two 2350 Kg, 2 K cooled, aluminum bar
detectors: NAUTILUS, located in Frascati (Italy), and EXPLORER, that was
located in CERN Geneva (CH). Both antennas are equipped with cosmic ray shower
detectors: signals in the bar due to showers are continuously detected and used
to characterize the antenna performances. The bar excitation mechanism is based
on the so called thermo-acoustic effect, studied on dedicated experiments that
use particle beams. This mechanism predicts that vibrations of bars are induced
by the heat deposited in the bar from the particle. The geometrical acceptance
of the bar detectors is 19.5 sr, that is smaller than that of other
detectors used for similar searches. However, the detection mechanism is
completely different and is more straightforward than in other detectors. We
will show the results of ten years of data from NAUTILUS (2003-2012) and 7
years from EXPLORER (2003-2009). The experimental limits we obtain are of
interest because, for nuclearites of mass less than grams, we find a
flux smaller than that one predicted considering nuclearites as dark matter
candidates.Comment: presented to the 33rd International Cosmic Ray Conference Rio de
Janeiro 201
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