1. Phys. Rev. Lett. 132, 051901 (2024) – Two-Pole Nature of the $\mathrm{\ensuremath{\Lambda}}(1405)$ Resonance from Lattice QCD (aps.org)
2. Phys. Rev. D 109, 014511 (2024) – Lattice QCD study of $\ensuremath{\pi}\mathrm{\ensuremath{\Sigma}}\ensuremath{-}\overline{K}N$ scattering and the $\mathrm{\ensuremath{\Lambda}}(1405)$ resonance (aps.org)

The “Final Result of the Majorana Demonstrator’s Search for Neutrinoless Double-β Decay in ⁷⁶Ge,” caught the eye of the scientific community becoming the most downloaded Nuclear Physics related paper that was published in Physical Review Letters in 2023.

From 2015 until 2021, the Majorana Demonstrator, tucked nearly a mile underground at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, searched for an elusive decay that might be the key to solving one of the universe’s biggest puzzles: why matter abounds rather than nothingness.  The postulated decay, known as neutrinoless double beta decay, if observed would reveal the quantum nature of neutrinos and prove that neutrinos are their own antiparticles.

The experiment’s final results, while not observing the decay, set a limit on the half-life of the decay of greater than 8 x 10²⁵ years (a timescale more than 10¹⁵ times longer than the age of the universe).  The experiment has helped pave the way for a next generation experiment known as LEGEND that aims to eventually have a hundred times the sensitivity of the Demonstrator.

UNC Physics and Astronomy faculty Julieta Gruszko, Reyco Henning, and John Wilkerson together with Matthew Busch from Duke, faculty member Matthew Green from NCSU, and UNC and NCSU graduate students and postdoctoral scholars made essential contributions to the  Majorana efforts.  UNC Postdoctoral fellow Ian Guinn (now at Oak Ridge National Laboratory) served as the paper’s corresponding author.  This collaborative research was supported and facilitated by the Triangle Universities Nuclear Laboratory(TUNL), a DOE Center of Excellence that is a consortium of UNC, Duke, NCSU, and NCCU nuclear physics researchers.

The Demonstrator was enabled by support from the  U.S. Department of Energy Office of Nuclear Physics and the National Science Foundation.

(Left: the Cover of the Article; Right: The Article has the most downloads under the Nuclear Physics section in 2023) 

A technological advance in medical and dental imaging promises to improve diagnostic accuracy while minimizing patient exposure to radiation, according to a research article in the Nature journal Communications Engineering.

In the article, “Volumetric Computed Tomography with Carbon Nanotube X-Ray Source Array for Improved Image Quality and Accuracy,” Shuang Xu, a Materials Science Ph.D. candidate in the Department of Applied Physical Sciences, demonstrated that multisource cone beam computed tomography (ms-CBCT), a type of X-ray imaging, has the potential to offer clinicians detailed 3-D imaging that will improve patient care and treatment.

Xu collaborated on the research with UNC-Chapel Hill Professors Christina Inscoe, Jianping Lu and Otto Zhou of the Department of Physics and Astronomy, Don Tyndall of the Adams School of Dentistry and Yueh Lee of the School of Medicine.

The researchers argue that ms-CBCT would be an improvement over conventional CBCT. Conventional CBCT is a specialized medical imaging technique that provides detailed 3-D volumetric images that offer a 360-degree spherical viewing angle of an object. CBCT imaging is used primarily in the fields of dentistry, maxillofacial surgery, interventional radiology and image-guided radiation therapy, where precise visualization of hard-tissue structures like teeth, jaws and the skull is crucial.

“Despite its advantages, conventional CBCT has limitations due to its large imaging volume,” said Xu. “These limitations include reduced soft tissue contrast, image distortion, use that is restricted primarily to imaging hard tissues and hindered quantitative analysis.”

Ms-CBCT overcomes these challenges by enhancing the accuracy of CT imaging of radiodensity of tissues by 60% and soft-tissue contrast by approximately 50%, allowing radiologists and clinicians to distinguish between different tissues and structures within the body. For example, in a CT scan of the abdomen, the liver might have a different HU value than the spleen, helping to identify and characterize abnormalities.

“This is a critical improvement,” said Otto Zhou, David Godschalk Distinguished Professor in the Department of Physics and Astronomy and a member of the APS adjunct faculty, “because accurate HU values are essential for quantitative analysis, tissue characterization and accurate diagnosis.”

In addition to improving image quality and diagnostic accuracy, ms-CBCT reduces the amount of “artifacts,” which can include the presence of metal objects, such as dental fillings or implants, and image distortion due to cone-beam imaging geometry.

“It’s a more comprehensive examination of the imaged area that can be particularly beneficial for capturing larger anatomical structures or regions of interest and improving soft-tissue contrast, making it possible to image more than just hard tissues,” said Xu.

CBCT systems utilize a cone-shaped X-ray beam, as opposed to the fan-shaped beam used in traditional systems. The cone-shaped beam is directed toward the patient or the specific region of interest and a flat-panel detector is positioned opposite the X-ray source. The detector captures the X-rays that pass through the patient, converting them into electrical signals. As the system rotates around the patient, it continuously emits the cone-shaped X-ray beam.

Ms-CBCT involves using multiple X-ray sources configured as an array. Instead of a single, wide cone-angle X-ray tube, this technology employs several X-ray sources that can be strategically positioned around the patient or imaging target. Carbon nanotubes have unique properties that make them suitable for X-ray emission, including their ability to efficiently generate electrons, as well as their small size.

“The ms-CBCT design holds promise for significantly enhancing the capabilities of CBCT scanners,” said Zhou. “These improvements could make CBCT a more versatile tool in medical and dental imaging, potentially competing with multidetector CT images in certain diagnostic applications while retaining its inherent advantages.”

(This article was originally published on the UNC-CH Applied Physical Sciences website. For more details, read the full article.)

December 19, 2023, Chapel Hill, North Carolina – The University of North Carolina at Chapel Hill (UNC-CH) chapter of the Society of Physics Students (SPS) has once again secured the coveted Outstanding Chapter Award from the SPS National Office. This marks the sixth consecutive year that the UNC-CH chapter has been acknowledged for its exceptional contributions as a top-tier student-led physical sciences organization. This designation is bestowed upon less than 15% of all SPS chapters at colleges and universities in the United States and internationally.

The SPS, a professional association for students, operates under the umbrella of the American Institute of Physics (AIP), encompassing various professional physical science societies.

Led by faculty advisor, Bowman and Gordon Gray Professor, Dan Reichart, the UNC-CH SPS chapter continues to exemplify excellence in student leadership. The officers for the 2022-2023 academic year are:

• President: Ravi Pitelka B.S. Physics, Mathematics B.A., Class of 2023
• Vice President: Vimal Palanivelrajan B.S. Physics, Mathematics B.S, Class of 2024
• Treasurer: Logan Selph B.S. Astrophysics, Currently Music Minor, Class of 2024
• Secretary: Stephen Snare B.S. Physics, Math B.A., Class of 2025
• Outreach Coordinator: Abbey Dunnigan B.S. Astrophysics, Class of 2024
• Events Coordinator: Em Chittenden B.S. Physics (Astrophysics Option), Class of 2024
• Room Managers: Rob Sternquist B.S. Physics, Mathematics B.S., Class of 2024; Landon Overall B.S. Physics, Class of 2023

“One of my favorite things about UNC SPS is how it gives opportunities to do things like go out camping with other physics majors. It’s a really useful resource when you need help on physics problems or with studying, but it’s also a great social space if you just want to hang out,” said Neel Iyer, the current Secretary for the 2024 – 2025 academic year.

SPS chapters undergo rigorous evaluation based on their engagement with the campus community, the professional physics community, the public, and SPS national programs. The Outstanding Chapter Award acknowledges not only high levels of outreach but also innovative approaches aligned with SPS’s mission to “help students transform themselves into contributing members of the professional community.”

For more information about the UNC-CH SPS chapter, please contact President Vimaleshwar Palanivelrajan (vbassic@email.unc.edu) or Secretary, Neel Wilson Iyer (iyern@unc.edu).

The Graduate-to-Undergraduate (G2U) Mentoring program at the University of North Carolina’s Department of Physics & Astronomy (P&A) has recently been awarded a $6,998 grant for unit enhancement by the College of Arts and Sciences’ Diversity, Equity, and Inclusion (DEI) initiative. This success marks a significant step forward for G2U, a program established in 2020 with the mission of providing structured, holistic mentorship to underrepresented minority (URM) undergraduate students in the department.

Mission and Vision

Founded by P&A graduate student Zack Hall with the invaluable support of Dr. Sheila Kannappan and Dr. Jennifer Weinberg-Wolf, G2U aims to create a robust support system for URM students in the department, where they constitute less than 10% of the undergraduate population. G2U is designed around findings and recommendations from an investigation of the persistent underrepresentation of African Americans in U.S. P&A departments, detailed in the American Institute of Physics TEAM-UP report. Accordingly, the program utilizes group-based mentoring and specialized event planning to foster a sense of community. intended to work towards increasing retention and inclusion for URM students in P&A. In March 2022 Science magazine published “The Missing Physicist” package, detailing the woeful lack of African American representation in physics, and G2U was featured among UNC P&A programs as a promising new approach to mitigate this. To date, G2U has over 30 mentees and mentors who have participated in this program.

DEI Grant Success

The success of the graduate student-led application for the DEI grant is a testament to the dedication and impact of the G2U program. The award, endorsed by Dr. Frank Tsui, chair of the department of P&A, recognizes the importance and impact of G2U. Out of nearly 50 submitted proposals, G2U’s stood out to the reviewers, comprised of the Climate Subcommittee of the Dean’s Diversity Advisory Committee. This reflects the department’s support for the College of Arts and Science’s Strategic Plan for DEI, Action Steps for Equity.

Grant Details

The grant will fund the G2U mentoring program from April 15, 2023, to June 30, 2024. This financial support has enabled the program to continue and expand its efforts in providing mentorship training for graduate student mentors and organizing monthly professional development and community-building events for undergraduate mentees. These include semester kick-off events, holiday celebrations, end-of-the-year festivities, and conference funding opportunities.

Context and Acknowledgement

G2U expresses heartfelt appreciation to the Department of Physics & Astronomy for its past funding and ongoing support. Special recognition goes to the faculty who support the development and execution of G2U, which includes Dr. Kannappan, Dr. Weinberg-Wolf, and Dr. Akaa Ayangeakaa, as well as Dr. Julieta Gruszko, who contributed funding through the DEI Scholars Program.  The department’s leadership played a pivotal role in providing funds during the program’s inaugural year, highlighting the commitment to fostering a diverse and inclusive academic environment. The department’s diversity committee has also been supportive of G2U’s mission and success. Finally, G2U emphasizes the importance of its graduate student members, both local and virtual, who actively participate as program coordinators and mentors.

Moving Forward

As the G2U Mentoring program moves forward with this grant, it is well aligned with the College of Arts and Sciences’ broader initiatives outlined in the Strategic Plan for Diversity, Equity, and Inclusion. The Action Steps for Equity outlines four DEI priorities, including enhancing climate, understanding pay equity, implementing measures for recruitment and retention, and addressing areas of repair.

For more information about the DEI grant, the College of Arts and Sciences’ initiatives, and the AIP TEAM-UP project please refer to the relevant web pages:

– College of Arts and Sciences Initiatives

– College of Arts and Sciences Strategic Plan for Diversity, Equity, and Inclusion

– AIP National Task Force to Elevate African American Representation in Undergraduate P&A

This achievement marks a significant milestone for G2U, reflecting its commitment to fostering an inclusive and supportive environment for underrepresented minority students pursuing their passion for physics and astronomy at UNC. The program looks forward to the positive impact it will continue to make with the support of the DEI grant.

To celebrate and resonate with the launch of the Long Range Plan,  a simultaneous hybrid in-person/virtual event titled “Update on the Long Range Plan for Nuclear Science” is scheduled for October 6th, from 2 pm – 3 pm EDT. This event is national in scope and welcomes all interested members of the scientific community and beyond. Gail Dodge, the NSAC Chair, will present a webinar via Zoom, complemented by a local component.

In the triangle area, we invite all the faculty, staff, postdocs, and students of the Triangle Universities to join this Update, as this event holds significant implications for all. The gathering will take place at 2 pm on the Duke Campus, specifically in Room 128 of the Physics Building. For detailed information, please refer to the poster below.

For those who require parking: please contact Mehreen Farooq (mehreen.farooq@duke.edu, 919-660-2600).

Renowned physicist and cosmologist Professor Edward “Rocky” Kolb will be making an exciting visit to UNC Physics and Astronomy on March 27th and 28^th, as part of the New Horizon’s Distinguished Speaker Series hosted by the Institute of Cosmology, Subatomic Matter and Symmetries (CoSMS).

During his visit, Professor Kolb will deliver a colloquium titled “Schrödinger’s Alarming Phenomenon” on March 27th at 3:30 PM in Room 211, Chapman. Afterward, there will be a special reception to welcome his visit. The following day, he will be giving a free public lecture entitled “The Quantum and The Cosmos” at 6:00 PM at UNC Morehead Planetarium.

Professor Kolb is a leading expert in cosmology, making significant contributions to our understanding of the early universe and the nature of dark matter. He is also passionate about public engagement with science, and he’s recognized for his engaging and accessible approach to science communication. His visit promises to be of great interest not only to UNC Physics and Astronomy faculty, researchers, students, and CosMS members, but also to the general public.

This is an excellent opportunity to gain insights from a world-class physicist and cosmologist, learn about the latest research in the field of cosmology, and engage with a passionate science communicator. Don’t miss this exciting visit by Professor Kolb to UNC Physics and Astronomy. Check out the flyers below for more information.

Professor Yosuke Kanai has recently published a paper in Physical Review Letters (PRL), the issue 11/2023, which has been selected as an Editor’s Suggestion and featured in Physics Magazine of the American Physical Society (APS).

This week’s issue of Physical Review Letters (PRL) features the article “Electronic Excitation Response of DNA to High-energy Proton Radiation in Water” by Professor Yosuke Kanai, Dr. Dillon Yost, and Mr. Chris Shepard as its co-authors. Professor Yosuke Kanai is an Adjunct Professor in the Department of Physics and Astronomy in addition to being a Professor in the Department of Chemistry at UNC.

Understanding the radiation-induced response of DNA is pivotal for human health. The electronic excitation induced in DNA by high-energy protons is central to understanding how DNA damage occurs in extreme conditions such as those experienced by astronauts. For instance, as much as 90% of galactic cosmic radiation (GCR) is high-energy protons, and human exposure to GCR is a great concern for space missions. The electronic response of DNA to high-energy protons is also the foundation of modern proton beam cancer therapy. The energy transfer rate from irradiating protons to electrons in the target matter is quantified by so-called electronic stopping power, and it plays a central role in understanding the electronic stopping phenomenon. Starting with the seminal work by Hans Bethe in 1930, many researchers have developed linear-response models for calculating the electronic stopping power. Over the last ten years, Prof. Kanai’s group has developed a new computational formalism such that quantum dynamics responsible for electronic stopping is directly simulated from first-principles quantum mechanical theory[1]. Building on their earlier work on water[2], the new PRL discusses how sugar-phosphate side chains of DNA respond strongly to irradiating protons due to the lone-pair electrons when DNA is solvated in water. As a result, positively charged holes are formed with a greater probability on the DNA side chains than on the nucleobases. This work advances our understanding of how the exposure of DNA to highly energetic protons can result in double-strand breaks in DNA, which are particularly important in inducing cell death.

1. C. Yost, Y. Yao, Y. Kanai
2. Phys. Chem. Lett. 11, 229 (2020)

1. Yao, D. Yost, Y. Kanai, Phys. Rev. Lett., 123, 066401 (2019)

One of our recent physics graduates, Tyler Kay, has been recognized for his outstanding work at the 2023 SPIE Medical Imaging conference in San Diego recently. Tyler’s poster presentation on his undergraduate research project completed at UNC, “Comparing multi-view synthetic radiography derived from tomosynthesis with standard bitewing radiography”, was awarded at the event.

The SPIE Medical Imaging conference is a highly respected platform that brings together researchers, scientists, and medical professionals from around the world to share their latest findings and innovations in image processing, physics, computer-aided diagnosis, perception, image-guided procedures, biomedical applications, ultrasound, informatics, radiology, and digital and computational pathology.

The NC Museum of Natural Science in Raleigh is a weekend destination for many families and science lovers. But visitors to the museum the weekend of Jan. 28-29 had an even more fantastic experience as Astronomy Days returned offline for 2023. This is one of the nation’s premier annual events on cosmology, offering a unique opportunity for outer space enthusiasts of all ages to explore and learn. This year’s Astronomy Days theme is Humans in Space: Past, Present, and Future.

“Want a sticker of the solar system planets? Which planet is your favorite? “Mars!”, “Saturn!”, “Neptune!”

Conversations like these continued to occur at the UNC Physics and Astronomy booths throughout the two days.

As is customary, UNC Physics and Astronomy is an active contributor and strong supporter of Astronomy Days. This year UNC’s booth was set up on the third floor of the museum and was divided into two themed booths. All exhibits were designed and organized by graduate and undergraduate volunteers from the UNC Department of Physics and Astronomy. Over the course of two days, 16 student volunteers welcomed hundreds of visitors.

Of course, the students didn’t just share their knowledge and love of physics and astronomy through spreading stickers. At the “UNC Physics and Astronomy” booth, they designed fun little experiments to explain scientific principles such as Angular Momentum and Cartesian Diver. At the “Planet Hunters and Investigators” booth, visitors can use models to simulate planetary motion and learn about the Earth’s rotation, revolution and the creation of the day, night and seasons.

“I’ve always felt that knowledge about the universe is very grand and complex, and my child is still too young for her cognitive abilities to possibly understand these concepts.” a mother of Hailey, a six-year-old girl, shared with us, “But this form of sharing, this design, through little experiments, you feel like your common sense is being challenged then you want to learn more, and it’s an amazing experience. I think she’s starting to enjoy learning about the universe.”

Hailey’s Mom was not alone; many parents stopped at the booths and were pleasantly surprised by the enthusiasm and curiosity that erupted from their children. “I could feel the love and pride these students from UNC have for their field of study, and their passion was passed on to my children,” commented a mother of two boys and a toddler girl.

UNC Physics and Astronomy has been dedicated to spreading scientific knowledge to the general population and sharing the fascination and beauty of physics and astronomy. As more events return offline this year, it will also have more opportunities to connect with the public and sow the seeds of love for science.

This week’s issue of Physical Review Letters (PRL) features the article “Search for the Majorana Nature of Neutrinos in the Inverted Mass Ordering Region with KamLAND-Zen” with Professor Hugon Karwowski and Dr Aobo Li as its co-authors. The piece was also highlighted in Physics Magazine and chosen as an “Editor’s Suggestion”.

In her evaluation of the significance of this article, Laura Baudis, the editor of the Physics Magazine and professor in the Department of Physics of the University of Zurich, believes that the research will help physicists further uncover the mystery of neutrino.

More information about Professor Karwowski and Dr Li can be found below:

Professor Hugon Karwowski’s research interests include photofission, few-body physics, neutrinos and applied nuclear physics. Some of his representative publications include the First measurement of the strange axial coupling constant using neutral-current quasi-elastic interactions of atmospheric neutrinos at KamLAND (Nov 2022); Abundances of Uranium and Thorium Elements in Earth Estimated by Geoneutrino Spectroscopy (Aug 2022); Exploring the multi-humped fission barrier of 238U via sub-barrier photofission (Apr 2013);  Measurements of the^{48} Ca (γ, n) reaction (Sep 2011); Precision measurements of H2(d,p)H3 and H2(d,n)He3 total cross sections at Big Bang nucleosynthesis energies (Apr 2006). To learn more about Professor Karwowski, visit his Department of Physics and Astronomy faculty profile. 

Dr Aobo Li is an interdisciplinary experimentalist of artificial intelligence (AI) and neutrino physics. He received his B.S. in physics at the University of Washington in 2015 and then completed his graduate work at Boston University. After receiving his PhD in 2020, Aobo joined the University of North Carolina at Chapel Hill as a Postdoctoral Research Associate and COSMS Fellow, working with Professor Julieta Gruszko on Germanium detector experiments while maintaining his partial involvement in KamLAND-Zen. Aobo initiated and led the Germanium Machine Learning (GeM) group, bringing AI solutions to two Germanium detector experiments: Majorana Demonstrator and LEGEND, while leveraging resources to educate domestic and international collaborators to acquire AI experience. His research work has recently been honored with the APS 2023 Dissertation Award in Nuclear Physics and the UNC Postdoctoral Award of Research Excellence (PARE).

On January 9th, 2023, the Department of Physics and Astronomy held a colloquium on Measurements of Fission Product Yields Using Monoenergetic Neutron and Gamma-ray Beams in honor of Professor Hugon Karwowski on the occasion of his retirement. 

The colloquium celebrated Karwowski and his many years of service to the Department of Physics and Astronomy and UNC. In introducing Karwowski’s remarks, Yue WU, Kenan Distinguished Professor and the colloquium host, laid out his colleague’s prestigious career at UNC, which began in 1984 as an assistant to the associate professor of Physics. Wu said, “Hugon was very strict with the students, but they loved him very much. Students and young faculty alike found him to be the person to seek when they needed advice. We appreciate his wisdom, insight, empathy, and being steadily logical, rational, and humorous.” 

Dr Jack Silano from Lawrence Livermore National Laboratory (LLNL), who graduated from the Department of Physics and Astronomy at UNC six years ago and was supervised by Prof. Hugon, was the guest speaker for the colloquium. He has given an overview of a joint LLNL-LANL-TUNL research program aimed at performing high-precision FPY measurements using quasimonoenergetic neutron and gamma-ray beams at Triangle Universities Nuclear Laboratory. At the beginning of the presentation, Dr Silano also paid tribute to the impact of Professor Karwowski’s work in the field and the instruction and guidance he has received and benefited from. 

After the presentation and Q&A, a celebratory cake was shared, and a cordial, friendly and fun exchange took place. Before an audience of colleagues, current and former students, as well as honored guests, Karwowski delivered a very brief speech reflecting on his teaching and research career and looking forward to his upcoming retirement life. He would also go on to keep a focus on his research area. 

Professor Karwowski is loved by his students. On the RMP (rate my professors) website, previous students have left comments such as “one of the best professors you could get to know”, “Dr K is the coolest professor ever”, “Professor K is an incredible teacher and is more than just an instructor”, and “Love the man, he has a heart of gold.” 

Hugon Karwowski’s research interests include photofission, few-body physics, neutrinos and applied nuclear physics. Some of his representative publications include First measurement of the strange axial coupling constant using neutral-current quasi-elastic interactions of atmospheric neutrinos at KamLAND (Nov 2022); Abundances of Uranium and Thorium Elements in Earth Estimated by Geoneutrino Spectroscopy (Aug 2022); Exploring the multi-humped fission barrier of 238U via sub-barrier photofission (Apr 2013);  Measurements of the^{48} Ca (γ, n) reaction (Sep 2011); Precision measurements of H2(d,p)H3 and H2(d,n)He3 total cross sections at Big Bang nucleosynthesis energies (Apr 2006). To learn more about Professor Karwowski, visit his Department of Physics and Astronomy faculty profile.