Conveners
PPD Poster Session & Student Poster Competition Finals (26) | Session d'affiches PPD et finales du concours d'affiches étudiantes (26)
- David Morrissey (TRIUMF)
The next generation of long-baseline neutrino oscillation experiments that will search for CP-violation of neutrions will be limited by systematic uncertainties. One of the systematic uncertainties that needs to be reduced is the neutrino flux uncertainty, which can be improved with more precise measurements of the pion and kaon production by beams of protons. The EMPAHTIC experiment plans...
The SuperCDMS (Cryogenic Dark Matter Search) experiment has pioneered the use of low-temperature solid-state detectors to search for dark matter particle candidates.
Detectors operating in CDMSlite mode allowed searches for particles with masses down to about 2 GeV/$c^{2}$ by pushing the analysis threshold to nuclear recoil energies down
to about 0.5 keV. However, one of the main...
Neutrinos from Supernova 1987A were detected in coincidence in 3 different detectors (Baksan, IMB and Kamioka). However, only the Mont Blanc detector registered an early burst 4.7 hours before the other 3 detectors. This paper examines possible explanations for the non-observation of the early burst in the 3 detectors, and the possible astrophysical scenarios for a double burst, such as a...
Experiments currently searching for dark matter and studying properties of neutrinos require very low levels of radioactive backgrounds both in their own construction materials and in the surrounding environment. These low background levels are required so that the current and next generation experiments can achieve the required sensitivities for their searches. SNOLAB has several facilities...
DEAP-3600 is a single-phase liquid argon WIMP detector, operating at SNOLAB (Sudbury, Ontario) since 2016. With the 2km rock overburden, the facility boasts one of lowest muon flux in the word.
DEAP-3600 was built with the goal of being background-free in the region of interest for three years. The design choices made to meet this requirement meant that no calibration source could be deployed...
Hybrid mesons are hypothesized hadrons containing a constituent quark, antiquark, and gluon. Despite nearly 50 years of searching, hybrids have not yet been conclusively observed in experiment. Part of the problem could be due to hadron mixing, the idea that observed hadrons are actually superpositions of conventional mesons, hybrid mesons, and other combinations of constituents. To explore...
The accurate measurement of the very rare $K^+ \to \pi^+ \nu \overline{\nu}$ decay branching ratio will allow us to probe the flavour sector of the Standard Model (SM) up to unprecedented energy scales.
Thanks to the process particular structure, the branching fraction can be calculated very precisely within the SM. The current best prediction is $\mathcal{B}\left(K^+ \to \pi^+ \nu...
Many designs of dark matter detectors rely on ionization from a nuclear recoil. An essential characteristic of these detectors is the quenching factor: the ratio of energy deposited via ionization in the detector by a particle of a given energy via nuclear recoil to that via electronic recoil. The electronic response is straightforward to measure using radioactive sources. The obvious way to...
The Large Hadron Collider (LHC) Run II took place from 2015 until the end of 2018, with proton-proton collisions at 13 TeV centre-of-mass energies. During this time the ATLAS detector collected a large dataset of over 140 fb$^{-1}$. Some theories predict that WIMP dark matter can be produced in proton-proton collisions, yielding events with large missing transverse momentum carried by a dark...
Dark matter signals are expected to be observed in PICO as single bubbles uniformly distributed within the chamber volume, and so far no dark matter candidates have been detected. During the collection of neutron calibration data, what is observed in the PICO chambers are recorded single bubble events that look exactly like the expected dark matter signals, in addition to a dominant presence...
The search for dark matter is evolving, and the quest to reach lower cross-sections leads to new technologies. One of the newer proposals involves the use of a bubble chamber which employs noble elements (such as argon and xenon) as the active mass. The switch to these targets opens the possibility for a much lower sensitivity to backgrounds as well as an additional scintillation channel for...
Strong multi-b analysis:
A search for supersymmetry involving the pair production of gluinos decaying via third generation squarks into lightest neutralino ($\tilde\chi^0_1$) is performed. The final state contains large missing transverse momentum and several energetic jets, at least three of which must be identified as b-quarks. The analysis uses the dataset of proton-proton collisions with...
The quarks and gluons produced in proton-proton collisions form collimated sprays of particles, known as jets. They are produced at a very high rate at the Large Hadron Collider (LHC, at CERN in Geneva, Switzerland) and thus are part of almost all interesting pp collision analyses. Due to the complex structure of jets, only a part of their energy can be measured directly in the ATLAS detector....
The Cryogenic Underground TEst facility (CUTE) will be used to test detectors for the Super Cryogenic Dark Matter Search (SuperCDMS) experiment. SuperCDMS searches for interactions of dark matter, an unknown form of matter which so far has only been observed through its gravitational effects on astronomical scales, even though it appears to be the dominant form of matter in the universe.
It...
Presently the Belle II experiment at SuperKEKB is colliding $e^+e^-$ beams at the $\Upsilon(4S)$ resonance. These beams currently have no polarization, but if SuperKEKB and Belle II were to be upgraded to make use of polarized electron beams a significant number of electroweak precision measurements could be made. However, in addition to the technical difficulties in creating a polarized beam...
DEAP-3600 is a direct detection dark matter experiment using a cryogenic liquid Argon target mass. The detector is situated within a water tank and placed 2 kilometres underground at SNOLAB to shield it from outside sources of radiation. However, contaminants on the inner surface of the spherical acrylic vessel (AV) can trigger the detector and must be removed using data analysis. A cut is...
SuperCDMS at SNOLAB is a direct search experiment for dark matter, targeting dark matter particles with low mass ($\leq$ 10 GeV/c$^2$). In order to achieve the projected sensitivity, a lower background, in addition to lower threshold energy, are a necessity. In the past, detector calibration was performed using radioactive sources. Currently, we are exploring the possibility of using LED-based...
This talk presents a novel new method for identifying electromagnetic vs. hadronic showers in the Belle II electromagnetic calorimeter though the first implementation of CsI(Tl) pulse shape discrimination (PSD) at a B-factory experiment. During the first run of collision data-taking of the Belle II experiment in summer 2018, the 8736 CsI(Tl) crystals in the Belle II calorimeter were...
We consider the formation and evolution of Axion Quark Nugget dark matter particles in the early universe. The goal of this work is to estimate the mass distribution of these objects and assess their ability to form and survive to the present day. We argue that this model allows a broad range of parameter space in which the AQN may account for the observed dark matter mass density, naturally...
The IceCube Neutrino Observatory is a large volume neutrino detector located two kilometers below the South Pole. Over one cubic kilometer of the ice is instrumented with 5,160 Digital Optical Modules (DOM) each containing a 10 inch diameter photomultiplier tube. The DOM’s photon acceptance has been measured in the lab, but does not accurately represent the behavior seen in ice. This...
Neutrino trident production (NTP) is a standard model (SM) sub-dominant process where two charged leptons are produced via neutrino-nucleus scattering. Presence of additional beyond standard model (BSM) vector and scalar bosons can increase NTP cross-sections significantly. Thus the observation of trident events in neutrino detectors can be used as a powerful probe into the search for new...
SNO+ is a multipurpose neutrino detector located approximately 2 km underground in SNOLAB, Sudbury, Ontario, Canada. The first phase of the experiment, running with ultrapure water, is now concluded and one of the goals is to detect reactor antineutrinos. Neutrino physics is answering important questions about the structure and behaviour of our universe, including our understanding of neutrino...
As dark matter detectors grow larger and more efficient, neutrinos from the sun and other cosmological sources become a significant background. If predictions hold true, the next generation of detectors is set to reach the neutrino floor. The neutrino floor typically shown was computed specifically for an ideal Xenon scintillator detector, using a Maxwellian speed distribution for the dark...
The PICO experiment uses bubble chambers filled with superheated C$_3$F$_8$ for spin-dependent WIMP dark matter searches. One of the main sources of background in these detectors is alpha particles from decays of environmental $^{222}\mathrm{Rn}$, which nucleate bubbles that are visually indistinguishable from WIMP candidate events. It was previously determined that alpha-induced bubbles can...
PICO is a direct Dark Matter detection experiment installed at SNOLAB searching for WIMPs (Weakly-Interacting Massive Particles) using the superheated liquid technique. A slight perturbation in the liquid, e.g. energy deposited by a recoiling nucleus due to its elastic collision with an incoming neutron, can create a bubble. The neutron-induced bubbles produce a signal indistinguishable from...
The PICO experiment is a dark matter direct-detection experiment
at SNOLAB, which has set world-leading limits on the spin-dependent
couplings of WIMPs to nucleii in the mass range of approximately 10-
100 GeV. There have been several iterations of the PICO detector;
each is a bubble chamber with a super-heated fluid as the active ma-
terial. The current version of the PICO detector is...
After a successful three-year run at 13 TeV, the Large Hadron Collider has paused operation, and will not circulate beams again until 2021. During this shutdown period, extensive repairs and upgrades will be made to the LHC and its experiments. For the ATLAS experiment, the major upgrade will be to the muon spectrometer in the form of the New Small Wheels (NSW). The NSW will serve in the Level...
Detailed tests of the Standard Model nature of the Higgs boson are a key component of the physics program at the ATLAS experiment. An overview of inclusive and fiducial differential cross section measurements in the HZZ4l channel will be presented. Higgs boson candidate events are selected by identifying two pairs of same-flavour oppositely-charged leptons (electrons or muons). Total cross...
The recent discovery of the Higgs boson (h) is an affirmation of the
Standard Model (SM) of particle physics and concludes several decades of
experimental searches. However, the experimental investigation of its
properties has just begun. Current measurements of h properties permit
the fraction of h decays to Beyond-Standard-Model (BSM) particles to
be as high as approximately 30%. These...
