Physics 599: Astro-Particle Seminar
Seminar Time: Wednesdays at 3:30 PM (EST)
Location: Nielsen 506
Seminars are in person unless otherwise noted
Zoom Link: https://tennessee.zoom.us/j/91068374231
| Date | Speaker | Title |
January 25 |
Anthony Mezzacappa |
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February 1 |
Colter Richardson |
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February 8 |
Daniel Murphy |
Gravitational Wave Analysis from Chimera CCSN Simulation Data |
February 15 |
Adryanna Major |
COHERENT's new Tonne-Scale NaI Detector and Prospects for Supernova Neutrino Detection |
February 22 |
Stefan Knirck |
Axion Dark Matter Searches at Fermilab from GHz to Infrared: ADMX an |
March 1 |
Vince Cianciolo |
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March 8 |
Daniel Pershey |
Hunting for Dark Matter with COHERENT at the SNS
|
March 22 |
Shane Thompson |
Quantum Computation of Phase Transition in φ4 Scalar Field Theory |
March 29 |
Andrés Delannoy |
Precision Luminosity Measurement at CMS with the Pixel Luminosity Telescope |
April 5 |
Tyler Johnson |
|
April 12 |
Jahred Adelman |
Computational Challenges (and Solutions!) in Particle Physics |
April 19 |
Daniel Salvat |
|
April 26 |
Emery Nibigira |
Operation of the Silicon Strip Tracker of the CMS Detector at the LHC |
May 3 |
Nilotpal Mukherjee |
Preparing for the Next Galactic Core Collapse Supernova
The next Galactic core collapse supernova will be a watershed event, for many reasons. "Light curves" from three messengers – gravitational waves, neutrinos, and photons – will bring information about the explosive death of the massive star. Each messenger will bring information from deeper regions of the stellar core than the next: photons from the innermost ejecta, neutrinos from the surface of the proto- neutron star, and gravitational waves from all regions, down to the core's very center. In turn, these light curves will allow us to test core collapse supernova models, provide information about the nascent neutron star, and probe exotic neutrino and nuclear physics inaccessible to terrestrial experiment. Core collapse supernova modeling – at least, computational modeling – began nearly sixty years ago. That we are still modeling such supernovae and in search of the details of the supernova "central engine" reflects the complexity of this multi-physics, multi-scale, and truly multidimensional problem. But significant progress has been made. Yet significant work remains. I will lay out the central problem, discuss the state of modeling efforts, and enumerate the significant challenges that lie ahead if we are to reap the fruit of what a Galactic core collapse supernova detection – a statistically once-in-a-lifetime event – together with high-fidelity core collapse supernova models would yield.
Detection and Reconstruction Prospects for Low-Frequency Gravitational Waves from Core-Collapse Supernovae
The detection of gravitational waves from a Core-Collapse Supernova is within the LIGO-Virgo-KAGRA Collaboration's reach. With the advancement of current detectors and the proposals for new detectors their reach becomes shorter and shorter, where if nature is kind, we will be ready for the next Galactic CCSN. In this presentation I will discuss aspects of both current and future detectors and the efforts of the LVK to make these detections possible. However, detection of an event is not enough, so I will also present on proposed data analysis techniques to extract the very low-frequency portion of the CCSN GW signals.
Gravitational Wave Analysis from Chimera CCSN Simulation Data
Core-collapse supernovae (CCSNe) are the explosions of massive stars at the end of their lives. They are among the most energetic events in the universe, directly or indirectly lead to the production of the vast majority of the elements, give rise to compact remnants (e.g., neutron stars, black holes), and ultimately strongly influence galactic chemical and thermal evolution. Additionally, they produce gravitational waves strong enough to be detected by current-generation gravitational wave observatories, such as Advanced LIGO and VIRGO, for a Galactic event. Using the data produced by the state-of-the-art UT-ORNL CCSN simulation code, Chimera, gravitational wave analysis has been done to investigate the predicted waveforms from several different explosion models corresponding to different stellar progenitors. Using Fourier analysis, these waveforms can be decomposed into their spectral components. Specific features of the spectrograms can be linked with specific dynamics in the CCSN evolution, providing us a way of observing these dynamics when a gravitational wave detection occurs. Further insights are obtained by calculating the gravitational wave emission, and its spectral representation, by region. I will present the spectrograms produced from three, three-dimensional Chimera simulations. I will link the observed gravitational wave properties to specific regions and events that occur during the CCSN evolution. Currently, the effects of varying the equation of state (EoS) in two-dimensional Chimera simulations is being investigated. I will present initial results that indicate the EoS may be able to be constrained by observation of gravitational waves.
COHERENT's New Tonne-Scale NaI Detector and Prospects for Supernova Neutrino Detection
The COHERENT collaboration operates a multi-target suite of low-threshold neutrino detectors at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. These detectors are uniquely equipped to observe the dominant low-energy (E v ~10s of MeV) interaction of coherent elastic neutrino-nucleus scattering (CEvNS). The only experimental trace is a nuclear recoil of mere tens of keV. To probe the distinctive neutron-number-squared scaling of CEvNS's Standard Model cross sections, COHERENT invokes the spice of life: variety. The CEvNS detector targets thus far range across CsI, LAr, Ge, and NaI, with a supplemental d2O detector for determining the neutrino flux.The COHERENT program is expanding, and a large scintillating NaI[Tl] detector—christened NaI Neutrino Experiment TonnE-scale (NaIvETe)—is among the new generation. Tasked with measuring CEvNS on the relatively light 23Na nucleus, its design capitalizes on a custom dual-gain PMT base to facilitate simultaneous measurements of CEvNS on 23Na and of charged-current interactions on 127I. Each of the five modules will contain 63 of the 7.7-kg crystals, a total mass of over 2.4 T. The first test module (470kg) of NaIvETe is configured for a CEvNS search and taking production data. Adding to this successful deployment, subsequent modules are in construction and will be deployed in 2023.And while we build, the universe destroys. A core-collapse supernova—rare and mighty—will eject a burst of neutrinos in the course of seconds, a high-flux source that tells the story of complex astrophysical phenomena. The CEvNS process dominates the interaction rate in the supernova neutrino burst (SNB) energy range (10s of MeV). As a flavor-blind interaction, CEvNS can measure the burst's total energy and flux in a vital fashion. The prospects for SNB detection will be explored for COHERENT as well as for scintillating neutrino experiments more broadly.
Axion Dark Matter Searches at Fermilab from GHz to Infrared: ADMX and BREAD
ADMX (Axion Dark Matter eXperiment) is the world-leading search for QCD axion dark matter in the µeV mass range. It searches for axions converting to GHz photons in a resonant cavity in a high magnetic field. Current results exclude most QCD axion dark matter from 2.7µeV and 4.2µeV [PRL 127(2021) 261803] with ongoing runs until 2GHz (8µeV) including a future implementation using an array of 4 cavities. With ADMX-EFR (extended frequency range) and using an array of 18 cavities Fermilab is poised to host the next generation of the experiment to cover a range from 2-4GHz (8-16µeV) with DFSZ sensitivity in a 3 year operation. In the first part of this talk we review ADMX and discuss current results. We outline R&D for future runs and present a detailed sensitivity estimate for EFR. At higher masses, resonant setups become increasingly challenging. However, axions can convert to photons regardless of their mass at metallic surfaces in a high magnetic field. They can successively be focused onto a detector (dish antenna concept). We present BREAD (Broadband Reflector Experiment for Axion Detection), a dish antenna with a novel rotationally symmetric parabolic focusing reflector designed to take advantage of high-field solenoidal magnets. We recently demonstrated [PRL 128 (2022) 131801] that this concept has the potential to discover QCD axions of several decades in mass range. In the second part of this talk we show progress towards first stage BREAD pilot experiments for two distinct frequency ranges - GigaBREAD and InfraBREAD - sensitive to unexplored coupling strengths. We detail R&D on reflector characterization, horn antenna & sensor testing and signal readout. We also outline sensitivity estimates for future large-scale versions.
The nEDM@SNS Experiment, Where Systematic Errors Go To Die
The nEDM@SNS experiment will measure the neutron's electric dipole moment with unprecedented precision and major components have started to arrive at ORNL. In this talk I will review the experiment's status and discuss features of 3He co-magnetometry that allow for unique control and understanding of key systematic errors
Hunting for Dark Matter with COHERENT at the SNS
The COHERENT collaboration made the first measurement of coherent elastic neutrino nucleus scattering (CEvNS) in 2017 using a low-background, 14.6-kg CsI[Na] detector at the SNS. Since initial detection, this detector has opened a new era of precision CEvNS measurements by doubling the detector exposure and improving understanding of the detector response. We these improvements, we now use CsI[Na] data to make competitive constraints of beyond-the-standard-model physics. The CEvNS process is highly sensitive to extensions beyond the standard model, and, as the cross section is precisely predicted by the standard model, it is ideal for these searches. We will outline the breadth of the new physics accessible to CEvNS detectors at the SNS with a focus on detection of accelerator-produced dark matter. With our experience measuring CEvNS, we are sensitive to analogous coherent dark matter induced recoils in our detector. This is a novel approach for accelerator-based dark matter experiments. Searching in this channel is also very powerful, allowing relatively small detectors to explore new parameter space inaccessible to much larger detectors. We will discuss current data constraints from our CsI[Na] detector which placed the most stringent constraint on dark matter with a mass in the 10s of MeV and future sensitivity of the next generation of COHERENT detectors to discover dark matter.
Quantum Computation of Phase Transition in φ4 Scalar Field Theory
It has been demonstrated that the critical point of the phase transition in φ4 scalar quantum field theory in one space and time dimension can be approximated via a Gaussian Effective Potential (GEP). Here we demonstrate how this critical point may be estimated on quantum hardware. We perform quantum computations with various lattice sizes and show that there is evidence of a transition from a symmetric phase to a symmetry-broken phase. The two-site case is implemented on actual quantum hardware, while we show via simulations that the continuum critical point lies at λ/m2 ∼ 61.2, where λ is the coupling and m is the renormalized mass. To compute the effective potential, we first use the Variational Quantum Eigensolver algorithm (VQE) to determine the parameters for the Gaussian states. We then use these parameters to compute the effective potential as a function of 〈φ〉, using varying levels of hybrid quantum-classical computation. By modifying the Ansatz state, one can extend this procedure beyond GEP's in order to demonstrate the second-order nature of the true phase transition, as the GEP transition is only first-order.
Precision luminosity measurement at CMS with the Pixel Luminosity Telescope
The Pixel Luminosity Telescope is a silicon pixel detector dedicated to luminosity measurement at the CMS experiment. It consists of 48 silicon sensor planes arranged into 16 "telescopes'' such that particles originating from the CMS interaction point will pass through all three planes in the telescope. It takes advantage of the "fast-or'' readout mode built into the CMS Phase-0 pixel readout chip, which can be processed at a frequency of 40 MHz, to determine the instantaneous luminosity from the rate of triple coincidences. The full pixel information, including hit position and charge, is read out at a lower rate of ~3 kHz and can be used for studies of systematic effects in the measurement. A full rebuild of the PLT was installed in early July 2021 in anticipation of Run 3 of the LHC, which incorporates a few silicon sensors developed for the CMS Phase-2 upgrade for the High-Luminosity LHC. Several detailed studies will be presented that illustrate the impact of radiation damage on the detector performance during Run 2. The lessons learned from Run 2 and the outlook for Run 3 will be underlined.
First Search For Neutrino-Induced Nuclear Fission
Over 50 years ago, it was predicted that it is possible to split an atom with a neutrino interaction, but there has never been a concerted experimental effort to confirm this phenomenon. The existence of this process would inform nuclear astrophysics, nuclear reactor monitoring and give a vantage into a process that bridges both the weak and strong fundamental interactions. This would add the neutrino to the selective group of particles confirmed to induce nuclear fission. To that end, the NuThor Detector was built in 2022 as a dedicated neutrino-induced nuclear fission (hereafter referred to as "nuFission") detector on thorium. The NuThor Detector hermetically seals 52.0 kgs of thorium metal inside a novel, custom-made neutron multiplicity meter built to efficiently capture and detect fission neutrons peeled off of the fissioned thorium nuclei. Said neutron multiplicity meter is composed of gadolinium-doped water to moderate and capture the aforementioned neutrons. Then an array of 7.7 kg NaI[Tl] scintillator crystals from the Homeland Security Advanced Portal Program are affixed all around the complex of thorium and Gd-Water to detect neutron-capture gamma rays. This entire apparatus is exposed to the intense neutrino flux of the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. The immense, pulsed neutrino source is coupled with the seasoned neutrino experimenters of the COHERENT collaboration to present a unique and promising opportunity to conclusively put this half century mystery of nuFission to rest. This work reports the design, deployment and sensitivity of the NuThor detector.
Computational Challenges (and Solutions!) in Particle Physics
In the next 1.5 decades, the LHC will deliver 20x more data than currently available to experiments. This rich data set will allow for exploration of new, exotic physics and precision tests of Standard Model predictions. The LHC experiments will face many challenges in dealing with this explosion in data size, including significant strains on the available software and computing resources. In this talk, I will focus on the ATLAS experiment and explain the computational chain necessary for LHC measurements and publications. I will then describe the rich R&D that ATLAS is pursuing to fit within future computational resources. The talk will conclude by explaining a new traineeship program starting at NIU this year to provide funding for graduate students to learn advanced computational skills in particle physics.
Measuring the neutron lifetime with UCNτ at LANSCE
Measuring the neutron lifetime with UCNτ at LANSCEThe β-decay of the neutron is one of the simplest manifestations of the weak interaction, with a robust theoretical prediction in the Standard Model. In concert with measurements of the neutron β-asymmetry it can test for beyond-SM physics that is being probed by nuclear decays and high energy experiments. Using the UCNτ apparatus at the Los Alamos Neutron Science Center, we have performed the most precise measurement of the neutron β-decay lifetime to date using a magneto-gravitational ultracold neutron (UCN) trap and ZnS scintillator-based UCN counter. In this talk, I will review the development of the experiment and discuss the analysis and results from our 2017-2018 measurement campaign. I will then outline the more recent data acquired with UCNτ and discuss plans to improve the number of UCN loaded into the trap and improving the UCN counter to handle the increased counting rates.
Operation of the Silicon Strip Tracker of the CMS Detector at the LHC
The CMS detector at Large Hadron Collider (LHC) is a multipurpose detector equipped with capabilities to identify electrons, muons, photons, as well as charged and neutral hadrons. Its tracking system consists of two silicon based sub-detectors: the inner tracker with pixels and the outer tracker with strips. The silicon strip tracker has an active area of approximately 200 m2 containing more than 15000 silicon modules. In this talk, the operation and performance of the silicon strip tracker during the LHC Run 2 data taking will be presented. The performance during the early Run 3 collisions will also be discussed.
A Closer Look at the Orbital Decay in M82 X-2
Ultra-luminous X-Ray Source(s) ULX are X-Ray sources that are located relatively far from the center of their host galaxy with luminosity that exceed the Eddington limit of a stellar mass blackhole (L_x > 10E+39 erg/s). X-ray variability suggests that ULXs are binaries with a nondegenerate star,a "donor",transferring mass onto a compact object,the "accretor". Some of these sources appear to pulsate at timed intervals leading to the conclusion that they may have a neutron star as their accretor. The first such Pulsating Ultra-luminous X-Ray Source (PULX) to be discovered was M82 X-2, a highly luminous X-ray source coming formt M-82 or the Cigar Galaxy. There are two current explanations for its unnatural brightness: 1) Extreme mass transfer rate or 2) luminosity boosted by geometrical beaming. For my presentation I will give a summary of the paper: https://arxiv.org/abs/2112.00339 where the authors argue in favour of the first option. By observing the orbital decay of the neutron star companion they conclude that its luminosity can be completely justified if the mass transfer rate is more than 150 times the Eddington limit without the need for any beaming effects.