182 research outputs found
Connecting blazars with ultra high energy cosmic rays and astrophysical neutrinos
We present a strong hint of a connection between high energy -ray
emitting blazars, very high energy neutrinos, and ultra high energy cosmic
rays. We first identify potential hadronic sources by filtering -ray
emitters %from existing catalogs that are in spatial coincidence with the high
energy neutrinos detected by IceCube. The neutrino filtered -ray
emitters are then correlated with the ultra high energy cosmic rays from the
Pierre Auger Observatory and the Telescope Array by scanning in -ray
flux () and angular separation () between sources and
cosmic rays. A maximal excess of 80 cosmic rays (42.5 expected) is found at
from the neutrino filtered -ray emitters
selected from the second hard {\it Fermi}-LAT catalogue (2FHL) and for
.
The probability for this to happen is , which translates to
after compensation for all the considered trials. No
excess of cosmic rays is instead observed for the complement sample of
-ray emitters (i.e. not in spatial connection with IceCube neutrinos).
A likelihood ratio test comparing the connection between the neutrino filtered
and the complement source samples with the cosmic rays favours a connection
between neutrino filtered emitters and cosmic rays with a probability of
( after compensation for all the considered
trials. The neutrino filtered -ray sources that make up the cosmic rays
excess are blazars of the high synchrotron peak type. More statistics is needed
to further investigate these sources as candidate cosmic ray and neutrino
emitters.Comment: Accepted for publication in MNRAS, added one figure (redshift
distribution), new IceCube data, and penalty factor for subsets within single
catalogue
Vetoing atmospheric neutrinos in a high energy neutrino telescope
We discuss the possibility to suppress downward atmospheric neutrinos in a
high energy neutrino telescope. This can be achieved by vetoing the muon which
is produced by the same parent meson decaying in the atmosphere. In principle,
atmospheric neutrinos with energies TeV and zenith angle up to 60
degree can be vetoed with an efficiency of > 99%. Practical realization will
depend on the depth of the neutrino telescope, on the muon veto efficiency and
on the ability to identify downward moving neutrinos with a good energy
estimation.Comment: 10 pages, 3 figures, accepted for publication in Physical Review
Correlating high-energy IceCube neutrinos with 5BZCAT blazars and RFC sources
We investigate the possibility that blazars in the Roma-BZCAT Multifrequency
Catalogue of Blazars (5BZCAT) are sources of the high-energy astrophysical
neutrinos detected by the IceCube Neutrino Observatory, as recently suggested
by Buson et al. (2022a,b). Although we can reproduce their
result, which applies to 7 years of neutrino data in the Southern sky, we find
no significant correlation with 5BZCAT sources when extending the search to the
Northern sky, where IceCube is most sensitive to astrophysical signals. To
further test this scenario, we use a larger sample consisting of 10 years of
neutrino data recently released by the IceCube collaboration, this time finding
no significant correlation in either the Southern or the Northern sky. These
results suggest that the strong correlation reported by Buson et al. (2022a,b)
using 5BZCAT could be due to a statistical fluctuation and possibly the spatial
and flux non-uniformities in the blazar sample. We perform some additional
correlation tests using the more uniform, flux-limited, and blazar-dominated
Radio Fundamental Catalogue (RFC) and find a equivalent
p-value when correlating it with the 7-year Southern neutrino sky. However,
this correlation disappears completely when extending the analysis to the
Northern sky and when analyzing 10 years of all-sky neutrino data. Our findings
support a scenario where the contribution of the whole blazar class to the
IceCube signal is relevant but not dominant, in agreement with most previous
studies.Comment: Accepted for publication in ApJ
New Constraints on Supersymmetry Using Neutrino Telescopes
We demonstrate that megaton-mass neutrino telescopes are able to observe the
signal from long-lived particles beyond the Standard Model, in particular the
stau, the supersymmetric partner of the tau lepton. Its signature is an excess
of charged particle tracks with horizontal arrival directions and energy
deposits between 0.1 and 1 TeV inside the detector. We exploit this
previously-overlooked signature to search for stau particles in the publicly
available IceCube data. The data shows no evidence of physics beyond the
Standard Model. We derive a new lower limit on the stau mass of GeV (95\%
C.L.) and estimate that this new approach, when applied to the full data set
available to the IceCube collaboration, will reach world-leading sensitivity to
the stau mass ()
Status and prospects of the IceCube neutrino telescope
The IceCube neutrino observatory, under construction at the South Pole,
consists of three sub-detectors: a km-scale array of digital optical modules
deployed deep in the ice, the AMANDA neutrino telescope and the surface array
IceTop. We summarize results from searches for cosmic neutrinos with the AMANDA
telescope and review expected sensitivities for IceCube at various installation
phases. Reliability and robustness of installation at the South Pole has been
demonstrated during the past four successful construction seasons. The 40
installed IceCube strings are working well. We are developing detailed plans
for the final construction of IceCube, including extensions optimized for low
and high energy. We describe the IceCube Deep Core project which will extend
the low energy response of IceCube.Comment: 8 pages, 10 pictures, proceeding of the International Workshop on a
Very Large Volume Neutrino Telescope for the Mediterranean Sea VLVnT08 -
Toulon, Var, France, 22-24 April 200
TeV Particle Astrophysics II: Summary comments
A unifying theme of this conference was the use of different approaches to
understand astrophysical sources of energetic particles in the TeV range and
above. In this summary I review how gamma-ray astronomy, neutrino astronomy and
(to some extent) gravitational wave astronomy provide complementary avenues to
understanding the origin and role of high-energy particles in energetic
astrophysical sources.Comment: 6 pages, 4 figures; Conference summary talk for "TeV Particle
Astrophysics II" at University of Wisconsin, Madison, 28-31 August 200
The effects of potato and rice starch as substitutes for phosphate in and degree of comminution on the technological, instrumental and sensory characteristics of restructured ham
peer-reviewedThe effects of sodium tripolyphosphate (STPP), two sources of starch (potato starch: PS and rice starch: RS) and comminution degree (CD) on the technological, instrumental and sensory characteristics of reformed hams were studied using response surface methodology. Both starches reduced cook loss and decreased ham flavour intensity, but RS had stronger effects on instrumental measures of texture, while PS was associated with improved juiciness when low/no added STPP was included. Coarsely ground meat, processed 100% with the kidney plate was associated with slightly increased cook loss, reduced texture profile analysis parameters and a more intense ham flavour compared to the other treatment (80% ground with a kidney plate plus 20% with a 9 mm plate). STPP was the sole factor affecting overall liking. If starch is included in the formulation, the standard level of STPP (0.3%) can be reduced by half with no increase in cook losses, but some decline in sensory quality cannot be avoided.Department of Agriculture, Food and the Marine, Irelan
- …