180 research outputs found
LHC phenomenology of dark matter with a color-octet partner
Colored dark sectors where the dark matter particle is accompanied by colored partners have recently attracted theoretical and phenomenological interest. We explore the possibility that the dark sector consists of the dark matter particle and a color-octet partner, where the interaction with the Standard Model is governed by an effective operator involving gluons. The resulting interactions resemble the color analogues of electric and magnetic dipole moments. Although many phenomenological features of this kind of model only depend on the group representation of the partner under SU(3)c, we point out that interesting collider signatures such as R-hadrons are indeed controlled by the interaction operator between the dark and visible sector. We perform a study of the current constraints and future reach of LHC searches, where the complementarity between different possible signals is highlighted and exploited
Simplified Models for LHC New Physics Searches
This document proposes a collection of simplified models relevant to the
design of new-physics searches at the LHC and the characterization of their
results. Both ATLAS and CMS have already presented some results in terms of
simplified models, and we encourage them to continue and expand this effort,
which supplements both signature-based results and benchmark model
interpretations. A simplified model is defined by an effective Lagrangian
describing the interactions of a small number of new particles. Simplified
models can equally well be described by a small number of masses and
cross-sections. These parameters are directly related to collider physics
observables, making simplified models a particularly effective framework for
evaluating searches and a useful starting point for characterizing positive
signals of new physics. This document serves as an official summary of the
results from the "Topologies for Early LHC Searches" workshop, held at SLAC in
September of 2010, the purpose of which was to develop a set of representative
models that can be used to cover all relevant phase space in experimental
searches. Particular emphasis is placed on searches relevant for the first
~50-500 pb-1 of data and those motivated by supersymmetric models. This note
largely summarizes material posted at http://lhcnewphysics.org/, which includes
simplified model definitions, Monte Carlo material, and supporting contacts
within the theory community. We also comment on future developments that may be
useful as more data is gathered and analyzed by the experiments.Comment: 40 pages, 2 figures. This document is the official summary of results
from "Topologies for Early LHC Searches" workshop (SLAC, September 2010).
Supplementary material can be found at http://lhcnewphysics.or
Implementation and first results of the KM3NeT real-time core-collapse supernova neutrino search
The KM3NeT research infrastructure is unconstruction in the Mediterranean Sea. KM3NeT will study atmospheric and astrophysical neutrinos with two multi-purpose neutrino detectors, ARCA and ORCA, primarily aimed at GeV–PeV neutrinos. Thanks to the multi-photomultiplier tube design of the digital optical modules, KM3NeT is capable of detecting the neutrino burst from a Galactic or near-Galactic core-collapse supernova. This potential is already exploitable with the first detection units deployed in the sea. This paper describes the real-time implementation of the supernova neutrino search, operating on the two KM3NeT detectors since the first months of 2019. A quasi-online astronomy analysis is introduced to study the time profile of the detected neutrinos for especially significant events. The mechanism of generation and distribution of alerts, as well as the integration into the SNEWS and SNEWS 2.0 global alert systems, are described. The approach for the follow-up of external alerts with a search for a neutrino excess in the archival data is defined. Finally, an overview of the current detector capabilities and a report after the first two years of operation are given
Searches for neutrinos in the direction of radio-bright blazars with the ANTARES telescope
Active galaxies, especially blazars, are among the most promising neutrino
source candidates. To date, ANTARES searches for these objects considered
GeV-TeV -ray bright blazars. Here, a statistically complete
radio-bright blazar sample is used as the target for searches of origins of
neutrinos collected by the ANTARES neutrino telescope over 13 years of
operation. The hypothesis of a neutrino-blazar directional correlation is
tested by pair counting and by a complementary likelihood-based approach. The
resulting post-trial -value is ( in the two-sided
convention), possibly indicating a correlation. Additionally, a time-dependent
analysis is performed to search for temporal clustering of neutrino candidates
as a mean of detecting neutrino flares in blazars. None of the investigated
sources alone reaches a significant flare detection level. However, the
presence of 18 sources with a pre-trial significance above indicates
a ( in the two-sided convention) detection of a
time-variable neutrino flux. An \textit{a posteriori} investigation reveals an
intriguing temporal coincidence of neutrino, radio, and -ray flares of
the J0242+1101 blazar at a ( in the two-sided convention)
level. Altogether, the results presented here suggest a possible connection of
neutrino candidates detected by the ANTARES telescope with radio-bright
blazars
The Power Board of the KM3NeT Digital Optical Module: design, upgrade, and production
The KM3NeT Collaboration is building an underwater neutrino observatory at
the bottom of the Mediterranean Sea consisting of two neutrino telescopes, both
composed of a three-dimensional array of light detectors, known as digital
optical modules. Each digital optical module contains a set of 31 three inch
photomultiplier tubes distributed over the surface of a 0.44 m diameter
pressure-resistant glass sphere. The module includes also calibration
instruments and electronics for power, readout and data acquisition. The power
board was developed to supply power to all the elements of the digital optical
module. The design of the power board began in 2013, and several prototypes
were produced and tested. After an exhaustive validation process in various
laboratories within the KM3NeT Collaboration, a mass production batch began,
resulting in the construction of over 1200 power boards so far. These boards
were integrated in the digital optical modules that have already been produced
and deployed, 828 until October 2023. In 2017, an upgrade of the power board,
to increase reliability and efficiency, was initiated. After the validation of
a pre-production series, a production batch of 800 upgraded boards is currently
underway. This paper describes the design, architecture, upgrade, validation,
and production of the power board, including the reliability studies and tests
conducted to ensure the safe operation at the bottom of the Mediterranean Sea
throughout the observatory's lifespa
Embedded Software of the KM3NeT Central Logic Board
The KM3NeT Collaboration is building and operating two deep sea neutrino
telescopes at the bottom of the Mediterranean Sea. The telescopes consist of
latices of photomultiplier tubes housed in pressure-resistant glass spheres,
called digital optical modules and arranged in vertical detection units. The
two main scientific goals are the determination of the neutrino mass ordering
and the discovery and observation of high-energy neutrino sources in the
Universe. Neutrinos are detected via the Cherenkov light, which is induced by
charged particles originated in neutrino interactions. The photomultiplier
tubes convert the Cherenkov light into electrical signals that are acquired and
timestamped by the acquisition electronics. Each optical module houses the
acquisition electronics for collecting and timestamping the photomultiplier
signals with one nanosecond accuracy. Once finished, the two telescopes will
have installed more than six thousand optical acquisition nodes, completing one
of the more complex networks in the world in terms of operation and
synchronization. The embedded software running in the acquisition nodes has
been designed to provide a framework that will operate with different hardware
versions and functionalities. The hardware will not be accessible once in
operation, which complicates the embedded software architecture. The embedded
software provides a set of tools to facilitate remote manageability of the
deployed hardware, including safe reconfiguration of the firmware. This paper
presents the architecture and the techniques, methods and implementation of the
embedded software running in the acquisition nodes of the KM3NeT neutrino
telescopes
Probing invisible neutrino decay with KM3NeT-ORCA
In the era of precision measurements of the neutrino oscillation parameters,
upcoming neutrino experiments will also be sensitive to physics beyond the
Standard Model. KM3NeT/ORCA is a neutrino detector optimised for measuring
atmospheric neutrinos from a few GeV to around 100 GeV. In this paper, the
sensitivity of the KM3NeT/ORCA detector to neutrino decay has been explored. A
three-flavour neutrino oscillation scenario, where the third neutrino mass
state decays into an invisible state, e.g. a sterile neutrino, is
considered. We find that KM3NeT/ORCA would be sensitive to invisible neutrino
decays with ~ at confidence
level, assuming true normal ordering. Finally, the impact of neutrino decay on
the precision of KM3NeT/ORCA measurements for ,
and mass ordering have been studied. No significant effect of neutrino decay on
the sensitivity to these measurements has been found.Comment: 27 pages, 14 figures, bibliography updated, typos correcte
Search for neutrino counterparts to the gravitational wave sources from O3 catalogues with the ANTARES detector
Since 2015 the LIGO and Virgo interferometers have detected gravitational
waves from almost one hundred coalescences of compact objects (black holes and
neutron stars). This article presents the results of a search performed with
data from the ANTARES telescope to identify neutrino counterparts to the
gravitational wave sources detected during the third LIGO/Virgo observing run
and reported in the catalogues GWTC-2, GWTC-2.1, and GWTC-3. This search is
sensitive to all-sky neutrinos of all flavours and of energies GeV,
thanks to the inclusion of both track-like events (mainly induced by
charged-current interactions) and shower-like events (induced by other
interaction types). Neutrinos are selected if they are detected within s from the GW merger and with a reconstructed direction compatible with
its sky localisation. No significant excess is found for any of the 80 analysed
GW events, and upper limits on the neutrino emission are derived. Using the
information from the GW catalogues and assuming isotropic emission, upper
limits on the total energy and on the fraction of the total
energy budget emitted as neutrinos of
all flavours are also computed. Finally, a stacked analysis of all the 72
binary black hole mergers (respectively the 7 neutron star - black hole merger
candidates) has been performed to constrain the typical neutrino emission
within this population, leading to the limits: erg and (respectively, erg and ) for spectrum and isotropic emission.
Other assumptions including softer spectra and non-isotropic scenarios have
also been tested.Comment: 13 pages, 4 figure
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