High Energy Particle and Astro Physics Seminar

Fall 2020

 

Announcement

Every Wednesday during this semester we will organize a presentation about research in High Energy Particle and Astro-Physics.

The seminars are online via Zoom. Links will be included in the weekly seminar announcements to students and faculty, and are on Canvas.

Everybody is welcome to attend! We particularly encourage undergraduate students and graduate students with research interest in subatomic and astro physics to attend and learn about ongoing research topics, trends, and future projects.

The Physics 599 seminar is also a 1-hour credit course. To earn credit, you will be asked to actively participate during the seminars (ask questions) and prepare a presentation about a research subject to be determined and discussed with faculty. Time for student presentations is at the end of the seminar series (November).

The first seminar is scheduled for Wednesday, August 26, 3:35pm.

Consider signing up for this course and/or make it a regular entry in your semester calendar.

For more details or if you are interested to give a presentation please contact the organizer, Stefan Spanier.

 

Schedule

 

August 26

The COHERENT Experiment

Jacob Daughhetee (UTK)

 

First Detection of Coherent Elastic Neutrino-Nucleus Scattering on Argon

In 2017, the COHERENT collaboration made the first observation of coherent elastic neutrino-nucleus scattering (CEvNS)

using a 14.6 kg CsI scintillating crystal detector located at the Spallation Neutron Source (SNS) at Oak Ridge National

Laboratory. In addition to neutrons, the 1.4 MW pulsed (60 Hz) proton beam at the SNS produces charged pions which

subsequently decay to yield a large neutrino flux with a well-known energy spectrum and time structure.

COHERENT employs a suite of detectors at the SNS to search for CEvNS in different target nuclei and to measure potential

backgrounds. This multi-target program allows for testing of Standard Model predictions for CEvNS as well as for verifying

the N^2 -dependence of the cross section of this interaction. CENNS-10, a 24 kg liquid argon scintillation detector, has been

actively taking data at the SNS since the spring of 2017. This talk will detail the methods and results of a search for and

detection of CEvNS in CENNS-10 data. Details of calibration analysis and uses of machine learning in CENNS-10 data will

also be reviewed.

 

September 2

Going the Distance: Searching for Overlooked Physics at LHC

Tova Holmes (UTK)

 

The LHC has reached a new era: nearly a decade without any large jumps in energy or luminosity. For those interested in finding Beyond the Standard Model (BSM) physics, a paradigm shift is required. In my talk Ill discuss a search program looking for long-lived particles, which often escape detection from standard BSM searches, due to the difficulty of triggering on and reconstructing their unconventional signatures. These challenges result in a long-lived particle landscape full of unexcluded territory, opening up opportunities to find TeV-scale Supersymmetry, hidden sectors, right-handed neutrinos, and more. My talk will focus on the challenge of triggering in these searches, and how we can expand our capability to explore these new signatures.

 

September 9

Neutron Stars

Andrew Steiner (UTK)

 

Combining Electromagnetic and Gravitational-Wave Constraints on Neutron-Star Masses and Radii

In this talk, I present our first combined analysis of data on 13 neutron stars from LIGO, NICER, Chandra, and other
observatories. We use this data to determine the neutron star mass-radius curve and the equation of state of dense matter. The photon-based observations have challenging systematic uncertainties, so we model our "unknown unknowns" by an additional "intrinsic scattering" in each data point. We find that no additional systematic uncertainty is required and that the photon-based observations agree with each other and with the LIGO measurement (with one possible exception). We also find that the EOS parameterization is becoming unimportant as the data improves.

September 16

A Future Muon Collider

Sergo Jindariani (Fermilab)

 

Muon Collider: The Dream Machine

Collider physics is rich, diverse, and versatile. It offers amazing opportunities at the Energy Frontier. Over the last several decades, colliders have played a central role in experimental establishment of the SM, from discovery of the charm quark in 1974 to the Higgs boson discovery in 2012. The Large Hadron Collider dataset will provide great opportunities for studies of the SM and will greatly extend the sensitivity for new physics. However, it is plausible that new colliders are necessary to shed light on the existence and nature of new physics. Muon Colliders present a highly attractive future collider option due to their small size, high efficiency, and the potential to reach very high energies. In this talk I will present the case for a future high energy muon collider, review associated challenges and advancements and outline the path forward.

 

September 23

Machine Learning and QC

Andrea Delgado (ORNL)

 

Exploring quantum computing for high-energy physics

For over two thousand years, people have thought about the fundamental particles from which all matter is made, starting with the gradual development of an atomic model, followed by a deeper understanding of the quantized atom, leading to the recent theory of the Standard Model (SM). The SM is amazingly successful, yet it leaves many basic questions unanswered. For example, parameters such as the cosmological constant, Higgs mass, or neutron electric dipole are unexplained. Thus, modern experimental particle physics generally investigates the SM and its various possible extensions through big-scale experiments that produce massive amounts of data.

The amount of information that is currently generated by particle physics experiments presents a challenge to conventional information technologies. As a result, the high energy physics (HEP) community is exploring innovative computing technologies, including quantum computing.

Quantum computing holds the promise of substantially speeding up computationally challenging tasks. However, we must improve our understanding of quantum computers, how quantum algorithms can be used within the HEP context, and when they can outperform their classical counterparts.

In the first part of this presentation, I will talk about a search for a new massive particle with properties similar to those of the SM Z boson. The search is motivated by the anomalies reported by the LHCb and Belle collaborations in the decay of B-mesons. In the second part of the talk, I will talk about the possibility of exploring quantum computing technologies for addressing the current and future computational challenges facing the HEP community.

 

September 30

DUNE

Josh Barrow (UTK)

 

Rare Processes and their Backgrounds

Simulations to Understand the Future Physics Potentials of DUNE

The possibility of explaining the baryon asymmetry of the universe via baryon minus lepton number-violating processes such as neutron-antineutron transformations has lead to great interest within the DUNE Collaboration. However, until recently and through still developing work, the signal region of this rare process, it's uncertainties, and associated backgrounds coming from atmospheric neutrinos were not entirely well known. Here I will present some current efforts and progress I and others have made within DUNE, the GENIE Monte Carlo event generator, and other small collaborations to better understand this rare signal. Secondarily, I will highlight some other current work on the possible future of high-precision lepton-nucleus cross sections using quantum Monte Carlo short-time approximation techniques within GENIE, which, in time, could greatly improve our atmospheric neutrino background estimates for rare processes while still further empowering the long-baseline neutrino oscillation program. 

 

October 7

Double Beta Decay

Vincente Guiseppe (ORNL)

 

The MAJORANA and LEGEND Programs: Searching for Neutrinoless Double-Beta Decay in Ge-76

Neutrinoless double-beta decay searches have the potential to discover the existence of a lepton-number violating process and the particle-antiparticle nature of neutrinos, which form the basis of theories explaining the matter-antimatter asymmetry in the universe. The Majorana Collaboration is operating its Demonstrator array of high-purity Ge detectors at the Sanford Underground Research Facility in South Dakota to search for neutrinoless double-beta decay in Ge-76. Along with the GERDA experiment in Italy, Ge-based experiments have achieved the lowest backgrounds and a superior energy resolution at the neutrinoless double-beta decay region of interest illustrating that Ge-76 is an ideal isotope for a large, next-generation experiment. Building on the successes of our experiments, the LEGEND collaboration has been formed to develop a phased, Ge-based double-beta decay experimental program with discovery potential at a half-life beyond 10^28 years. Our program relies on advances in detector design and a thorough understanding of existing and potentially new backgrounds. This talk will present the status and latest results from the MAJORANA DEMONSTRATOR experiment, studies of problematic background sources, and the plan for the LEGEND experiment.

 

October 14

Astrophysical Implications of Mirror Dark Matter (DM)

Zurab Berezhiani (L'Aquila University and LNGS, Italy)

 

Astrophysical implications of neutron -- mirror neutron oscillations

Dark matter in the universe might exist in the form of hidden mirror sector which is an exact replica of our sector of ordinary particles. I shall briefly discuss its cosmological implications. Distinguished feature of this concept is the possibility that the neutral ordinary particles, elementary (as e.g. neutrinos) or composite (as e.g. the neutron), can have substantial mixings with their mass degenerate mirror twins. In particular, I shall concentrate on neutron--mirror neutron oscillations and discuss some of its its astrophysical implications, namely for the ultra-high energy cosmic rays and for the neutron stars.

 

October 21

Off the beaten track: Unconventional Searches at LHC

Karri DiPetrillo (FNAL)

 

Our best hope for a beyond the Standard Model discovery at the LHC requires breaking long-held assumptions about how to look for new physics. In this talk, I will discuss some of the unconventional signatures motivated by models with a dark QCD sector. Predicted signatures range from jets in which displaced tracks appear to emerge from a dark sector, to events with many spherically distributed soft charged particles. A common theme for many of these searches are the challenges in triggering and offline reconstruction. I will discuss some of these challenges and recent progress on the hunt to discover new physics at the LHC. I will also touch on ways to expand our potential to look for such unconventional signatures in the future. 

 

October 28

Nucleosynthesis based on 3D Supernova simulations

Andres Sieverding (ORNL)

 

Nucleosynthesis of a low mass Supernova with 3D Simulation of the Inner Ejecta

 

Based on a 3D supernova simulation of an 11.8M progenitor model with initial solar composition, we study the nucleosynthesis using tracers covering the innermost 0.1M of the ejecta. These ejecta are mostly proton-rich and contribute significant amounts of 45Sc and 64Zn. The production of heavier isotopes is sensitive to the electron fraction and hence the neutrino emission from the proto-neutron star. In order to obtain the total yields for the whole supernova, we combine the results from the tracers with those for the outer layers from a suitable 1D model. Using the yields of short-lived radionuclides (SLRs), we explore the possibility that an 11.8M supernova might have triggered the formation of the solar system and provided some of the SLRs measured in meteorites (arXiv:2008.12831).

 

November 4

Accelerator light DM initiatives (LDMX, DarkQuest, M^3)

Nhan Tran (FNAL)

 

 

November 11

Student Session

 

 

November 18

Student Session

 

 

Brandi Skipworth

Spectral analysis of the quiescent low-mass X-ray binary in the globular cluster M30