R. J. Hegedus
A5017966817- Neutrino Physics Research
- Stellar, planetary, and galactic studies
- Particle physics theoretical and experimental studies
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Radiation Detection and Scintillator Technologies
- Sports Performance and Training
- Dark Matter and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Sports Dynamics and Biomechanics
- Particle Detector Development and Performance
- Advanced Data Storage Technologies
- Distributed and Parallel Computing Systems
- Nuclear physics research studies
- SAS software applications and methods
- Shoulder Injury and Treatment
- Atomic and Subatomic Physics Research
- Sports Analytics and Performance
University of North Carolina at Chapel Hill
2019-2023
Triangle Universities Nuclear Laboratory
2019-2022
High Point University
2015-2020
Queen's University
2019
Duke University
2019
North Carolina State University
2019
Technical University of Munich
2019
Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas
2019
The Majorana Collaboration is operating an array of high-purity Ge detectors to search for the neutrinoless double-$\ensuremath{\beta}$ decay $^{76}\mathrm{Ge}$. Demonstrator consists 44.1 kg (29.7 enriched 88% in $^{76}\mathrm{Ge}$) split between two modules constructed from ultraclean materials. Both are contained a low-background shield at Sanford Underground Research Facility Lead, South Dakota. We present updated results on $^{76}\mathrm{Ge}$ with $26.0\ifmmode\pm\else\textpm\fi{}0.5$...
We present follow-up photometry and spectroscopy of ZTF J0328$-$1219 strengthening its status as a white dwarf exhibiting transiting planetary debris. Using TESS Zwicky Transient Facility photometry, along with high speed from various observatories, we find evidence for two significant periods variability at 9.937 11.2 hr. interpret these most likely the orbital different debris clumps. Changes in detailed dip structures within light curves are observed on nightly, weekly, monthly...
Tidal disruption and subsequent accretion of planetesimals by white dwarfs can reveal the elemental abundances rocky bodies in exoplanetary systems. Those provide information on composition nebula from which systems formed, is analogous to how meteorite inform our understanding early Solar System. We report detection lithium, sodium, potassium, calcium atmosphere dwarf Gaia DR2 4353607450860305024, we ascribe a planetesimal. Using model atmospheres, determine abundance ratios these elements,...
Abstract Observations of debris disks, the products collisional evolution rocky planetesimals, can be used to trace planetary activity across a wide range stellar types. The most common end points are no exception, as disks have been observed around several dozen white dwarf stars. But instead formation, post-main-sequence signpost destruction, resulting in compact from tidal disruption remnant planetesimals. In this work, we present discovery five new stars with gaseous emission. All...
Abstract The bulk abundances of exoplanetesimals can be measured when they are accreted by white dwarfs. Recently, lithium from the accretion was detected in relatively high levels multiple There presently three proposed hypotheses to explain detection excess dwarf photospheres: Big Bang and Galactic nucleosynthesis, continental crust, an exomoon formed spalled ring material. We present new observations previously known lithium-polluted dwarfs (WD J1824+1213, WD J2317+1830, LHS 2534), one...
The Majorana Demonstrator is searching for neutrinoless double-beta decay ($0\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$) in $^{76}\mathrm{Ge}$ using arrays of point-contact germanium detectors operating at the Sanford Underground Research Facility. Background results $0\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$ region interest from data taken during construction, commissioning, and start full operations have been recently published. A pulse shape analysis cut applied to...
ABSTRACT We report the discovery of two apparently isolated stellar remnants that exhibit rotationally modulated magnetic Balmer emission, adding to emerging DAHe class white dwarf stars. While previously discovered members this show Zeeman-split triplet emission features corresponding single field strengths, these new objects significant fluctuations in their apparent strengths with variability phase. The hydrogen lines LP 705−64 broaden from 9.4 22.2 MG over an spin period 72.629 min....
P-type point contact (PPC) HPGe detectors are a leading technology for rare event searches due to their excellent energy resolution, low thresholds, and multi-site rejection capabilities. We have characterized PPC detector's response $\alpha$ particles incident on the sensitive passivated p+ surfaces, previously poorly-understood source of background. The detector studied is identical those in MAJORANA DEMONSTRATOR experiment, search neutrinoless double-beta decay ($0\nu\beta\beta$)...
We present the discovery of eclipsing double white dwarf (WD) binary WDJ 022558.21-692025.38 that has an orbital period 47.19 min. Following identification with Transiting Exoplanet Survey Satellite, we obtained time-series ground based spectroscopy and high-speed multi-band ULTRACAM photometry which indicate a primary DA WD mass 0.40 +- 0.04 Msol 0.28 0.02 secondary WD, is likely type as well. The system becomes third-closest discovered distance approximately 400 pc will be detectable...
In 2012, five high school students involved in the Pulsar Search Collaboratory discovered millisecond pulsar PSR J1400$-$1431 and initial timing parameters were published Rosen et al. (2013) a year later. Since then, we have obtained phase-connected solution spanning years, resolving significant position discrepancy measuring $\dot{P}$, proper motion, parallax, monotonic slope dispersion measure over time. Due to J1400$-$1431's proximity use Shklovskii effect other priors determine 95%...
The Majorana Demonstrator is an ultra-low-background experiment searching for neutrinoless double-beta decay in $^{76}\mathrm{Ge}$. heavily shielded array of germanium detectors, placed nearly a mile underground at the Sanford Underground Research Facility Lead, South Dakota, also allows searches new exotic physics. We present first limits trinucleon decay-specific modes and invisible Ge isotopes. find half-life limit $4.9\ifmmode\times\else\texttimes\fi{}{10}^{25}\text{ }\text{...
Abstract The MAJORANA DEMONSTRATOR is searching for double-beta decay of 76 Ge to excited states (E.S.) in Se using a modular array high purity Germanium detectors. can into three E.S.s Se. E.S. decays have clear event signature consisting ββ -decay with the prompt emission one or two γ -rays, resulting probability multi-site event. granularity detector enables powerful discrimination this from backgrounds. Using 21.3 kg-y isotopic exposure, has set world leading limits each decay, 90% CL...
The bulk abundances of exoplanetesimals can be measured when they are accreted by white dwarfs. Recently, lithium from the accretion was detected in relatively high levels multiple There presently three proposed hypotheses to explain detection excess dwarf photospheres: Big Bang and Galactic nucleosynthesis, continental crust, an exomoon formed spalled ring material. We present new observations previously known lithium-polluted dwarfs (WD J1824+1213, WD J2317+1830, LHS 2534), one with metal...
Imperfections in analog-to-digital conversion (ADC) cannot be ignored when signal digitization requirements demand both wide dynamic range and high resolution, as is the case for Majorana Demonstrator 76Ge neutrinoless double beta decay search. Enabling experiment's high-resolution spectral analysis efficient pulse shape discrimination required careful measurement correction of ADC nonlinearites. A simple protocol was developed that did not require sophisticated equipment or lengthy data...
Resistance training has been demonstrated to improve golf performance, though amateur female golfers have not received much attention in this regard. PURPOSE:To compare the effects of a traditional resistance program (TRAD), functional, golf-specific (FUN), on driver (DR) and 7-iron (7I) club head speed (CHS) total shot distance recreational golfers. METHODS: Twenty-nine (age: 18-71y) completed series baseline post-training tests which measured CHS simulator using high cameras. Muscular...
The MAJORANA DEMONSTRATOR is an experiment constructed to search for neutrinoless double-beta decay in $^{76}$Ge and demonstrate the feasibility deploy a large-scale phased modular fashion. It consists of two modules natural $^{76}$Ge-enriched germanium detectors totalling $44.1\ \mathrm{kg}$, operating at 4850' level Sanford Underground Research Facility Lead, South Dakota, USA. Commissioning began June 2015, followed by data production with full detector array August 2016. ultra-low...
The MAJORANA DEMONSTRATOR is searching for neutrinoless double-beta decay in $^{76}$Ge with two modular arrays of natural and $^{76}$Ge-enriched germanium detectors. It located at the 4850 level Sanford Underground Research Facility Lead, South Dakota, USA, its total mass detectors 44.1 kg, which 29.7 kg enriched. analysis first 26 kg-yr data provides an unprecedented energy resolution 0.13% region interest 2039 keV a background 15.4 $\pm$ 2.0 counts/(FWHM t yr). establishes lower limit...