From The Ohio State University
8.15.23
Tatyana Woodall
Ohio State News
woodall.52@osu.edu
When supernovae explode, neutrinos from their core carry enormous amounts of energy in all directions.
Photo: Getty Images
Long-standing scientific problem
In a new study, researchers have taken an important step toward understanding how exploding stars can help reveal how neutrinos, mysterious subatomic particles, secretly interact with themselves.
One of the less well-understood elementary particles, neutrinos rarely interact with normal matter, and instead travel invisibly through it at almost the speed of light. These ghostly particles outnumber all the atoms in the universe and are always passing harmlessly through our bodies, but due to their low mass and lack of an electric charge they can be incredibly difficult to find and study.
But in a study published today in the journal Physical Review Letters [below], researchers at The Ohio State University have established a new framework detailing how supernovae – massive explosions that herald the death of collapsing stars – could be used as powerful tools to study how neutrino self-interactions can cause vast cosmological changes in the universe.
“Neutrinos only have very small rates of interaction with typical matter, so it’s difficult to detect them and test any of their properties,” said Po-Wen Chang, lead author of the study and a graduate student in physics at Ohio State. “That’s why we have to use astrophysics and cosmology to discover interesting phenomena about them.”
Thought to have been important to the formation of the early universe, neutrinos are still puzzling to scientists, despite having learned that they originate from a number of sources, such as in nuclear reactors or the insides of dying stars. But by calculating how self-interactions would affect the neutrino signal from Supernova 1987A, the nearest supernova observed in modern times, researchers found that when neutrinos do interact with themselves, they form a tightly coupled fluid that expands under relativistic hydrodynamics – a branch of physics that deals with how flows impact solid objects in one of two different ways.
In the case of what’s called a “burst outflow,” the team theorizes that much like popping a highly pressurized balloon in the vacuum of space would push energy outward, a burst produces a neutrino fluid that moves in all directions. The second case, described as a “wind outflow,” imagines a highly pressurized balloon with many nozzles, wherein neutrinos escape at a more constant flow rate, similar to a jet of steady wind.
While the wind-outflow theory is more likely to take place in nature, said Chang, if the burst case is realized, scientists could see new observable neutrino signatures emitted from supernovae, allowing unprecedented sensitivity to neutrino self-interactions.
One of the reasons it’s so vital to understand these mechanisms is that if neutrinos are acting as a fluid, that means they are acting together, as a collective. And if the properties of neutrinos are different as a collective than individually, then the physics of supernovae could experience changes too. But whether these changes are due solely to the burst case or the outflow case remains to be seen.
“The dynamics of supernovae are complicated, but this result is promising because with relativistic hydrodynamics we know there’s a fork in the road in understanding how they work now,” said Chang.
Still, further research needs to be done before scientists can cross off the possibility of the burst case happening inside supernovae as well.
Despite these uncertainties, the study is a huge milestone in answering the decades-old astrophysical issue of how neutrinos actually scatter when ejected from supernovae, said John Beacom, co-author of the study and a professor of physics and astronomy at Ohio State. This study found that in the burst case, unprecedented sensitivity to neutrino self-interactions is possible even with sparse neutrino data from SN 1987A and conservative analysis assumptions.
“This problem has lain basically untouched for 35 years,” said Beacom. “So even though we were not able to completely solve how neutrinos affect supernovae, what we’re excited about is that we were able to make a substantial step forward.”
Down the road, the team hopes their work will be used as a stepping stone to further investigate neutrino self-interactions. Yet because only about two or three supernovae happen per century in the Milky Way, it’s likely researchers will have to wait decades more to collect enough new neutrino data to prove their ideas.
“We’re always praying for another galactic supernova to happen somewhere and soon, but the best we can do is try to build on what we know as much as possible before it happens,” said Chang.
Other co-authors were Ivan Esteban, Todd Thompson and Christopher M. Hirata, all of Ohio State. This work was supported by the National Science Foundation, NASA, and the David & Lucile Packard Foundation.
See the full article here .
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The Ohio State University is a public research university in Columbus, Ohio. Founded in 1870 as a land-grant university and the ninth university in Ohio with the Morrill Act of 1862, the university was originally known as the Ohio Agricultural and Mechanical College.
Ohio State has been ranked by major institutional rankings among the best public universities in the United States. Originally focused on various agricultural and mechanical disciplines, it developed into a comprehensive university under the direction of then-Governor and later U.S. president Rutherford B. Hayes, and in 1878, the Ohio General Assembly passed a law changing the name to “The Ohio State University” and broadening the scope of the university. Admission standards tightened and became greatly more selective throughout the 2000s and 2010s.
Ohio State’s political science department and faculty have greatly contributed to the construction and development of the constructivist and realist schools of international relations; a 2004 LSE study ranked the program as first among public institutions and fourth overall in the world. A member of the Association of American Universities since 1916, Ohio State is a leading producer of Fulbright Scholars, and is the only school in North America that offers an Accreditation Board for Engineering and Technology, Inc-accredited undergraduate degree in welding engineering. The university’s endowment of $6.8 billion in 2021 is among the largest in the world. Past and present alumni and faculty include five Nobel Prize laureates, nine Rhodes Scholars, seven Churchill Scholars, one Fields Medalist, seven Pulitzer Prize winners, 64 Goldwater scholars, six U.S. Senators, 15 U.S. Representatives, and 108 Olympic medalists. It is classified among “R1: Doctoral Universities – Very high research activity.” As of 2021, Ohio State has the most students in the 95th percentile or above on standardized testing of any public university in the United States.
The university has an extensive student life program, with over 1,000 student organizations; intercollegiate, club and recreational sports programs; student media organizations and publications, fraternities and sororities; and three student governments. Its athletic teams compete in Division I of the NCAA and are known as the Ohio State Buckeyes, and it’s a member of the Big Ten Conference for the majority of its sports. The school’s football program has had great success and is one of the major programs of college football; their rivalry against the University of Michigan has been termed as one of the greatest in North American sports. As of 2017, Ohio State’s football program is valued at $1.5 billion, the highest valuation of any such program in the country. The main campus in Columbus has grown into the third-largest university campus in the United States, with nearly 50,000 undergraduate students and nearly 15,000 graduate students. study ranked the program as first among public institutions and fourth overall in the world.
In 1906, Ohio State President William Oxley Thompson, along with the university’s supporters in the state legislature, put forth the Lybarger Bill with the aim of shifting virtually all higher education support to the continued development of Ohio State while funding only the “normal school” functions of the state’s other public universities. Although the Lybarger Bill failed narrowly to gain passage, in its place the Eagleson Bill was passed as a compromise, which determined that all doctoral education and research functions would be the role of Ohio State, and that Miami University and Ohio University would not offer instruction beyond the master’s degree level – an agreement that would remain in place until the 1950s.
With the onset of the Great Depression, Ohio State would face many of the challenges affecting universities throughout America as budget support was slashed, and students without the means of paying tuition returned home to support families. By the mid-1930s, however, enrollment had stabilized due in large part to the role of the Federal Emergency Relief Administration and later the National Youth Administration. By the end of the decade, enrollment had still managed to grow to over 17,500. In 1934, the Ohio State Research Foundation was founded to bring in outside funding for faculty research projects. In 1938, a development office was opened to begin raising funds privately to offset reductions in state support.
In 1952, Ohio State founded the interdisciplinary Mershon Center for International Security Studies, which it still houses. The work of this program led to the United States Department of Homeland Security basing the National Academic Consortium for Homeland Security at the university in 2003.
The Ohio State University and the University of Michigan football programs participated in The Ten Year War between 1969 and 1978. In consistently close matches, it pitted coaches Woody Hayes of Ohio State and Bo Schembechler of Michigan against each other. This heated era led to the persistent Michigan–Ohio State football rivalry.
Ohio State had an open admissions policy until the late 1980s; particularly since the early 2000s, the college has greatly raised standards for admission, and it has been increasingly cited as one of the best public universities in the United States. As of 2021, it has by far the most students in the country in the 95th percentile or above of test-takers on the ACT and SAT of any public university. The trend particularly began under former university administrator William Kirwan in 1998, who set out to greatly increase the quality of applicants and make the university an elite academic university.
Michael V. Drake, former chancellor of the University of California-Irvine, became the 15th president of the Ohio State University on June 30, 2014. He announced on November 21, 2019, that he would retire at the end of the 2019–2020 academic year. In 2019, Ohio State filed for trademark protection of “the” when it is used to refer to Ohio State; the application was denied. On June 3, 2020, the Ohio State Board of Trustees appointed Kristina M. Johnson, the former chancellor of The State University of New York, as the 16th president of the Ohio State University. The main campus in Columbus has grown into the third-largest university campus in the United States.
On June 22, 2022, the United States Patent and Trademark Office granted the university a trademark on the word “the” in relation to clothing, such as T-shirts, baseball caps and hats distributed and/or sold through athletic or collegiate channels. Ohio State and its fans, in particular those of its athletics program, frequently emphasizes the word “THE” when referring to the school.
The Public Ivies: America’s Flagship Public Universities (2000) by Howard and Matthew Greene listed Ohio State as one of a select number of public universities offering the highest educational quality. In its 2021 edition, U.S. News & World Report ranked Ohio State as tied for the 17th-best public university in the United States, and tied for 53rd among all national universities. They ranked the college’s political science, audiology, sociology, speech–language pathology, finance, accounting, public affairs, nursing, social work, healthcare administration and pharmacy programs as among the top 20 programs in the country. The Academic Ranking of World Universities placed Ohio State 42–56 nationally and 101–150 globally for 2020. In its 2021 rankings, Times Higher Education World University Rankings ranked it tied for 80th in the world. In 2021, QS World University Rankings ranked the university 108th in the world. The Washington Monthly college rankings, which seek to evaluate colleges’ contributions to American society based on factors of social mobility, research and service to the country by their graduates, placed Ohio State 98th among national universities in 2020.
In 1916, Ohio State became the first university in Ohio to be extended membership into the Association of American Universities, and remains the only public university in Ohio among the organization’s 60 members. Ohio State is also the only public university in Ohio to be classified among “R1: Doctoral Universities – Highest Research Activity” and have its undergraduate admissions classified as “more selective.”
Ohio State’s political science program is ranked among the top programs globally. Considered to be one of the leading departments in the United States, it has played a particularly significant role in the construction and development of the constructivist and realist schools of international relations. Notable political scientists who have worked at the university include Alexander Wendt, John Mueller, Randall Schweller, Gene Sharp and Herb Asher. In 2004, it was ranked as first among public institutions and fourth overall in the world by British political scientist Simon Hix at the London School of Economics and Political Science, while a 2007 study in the academic journal PS: Political Science & Politics ranked it ninth in the United States. It is a leading producer of Fulbright Scholars.
Bloomberg Businessweek ranked the undergraduate business program at Ohio State’s Fisher College of Business as the 14th best in the nation in its 2016 rankings. U.S. News & World Report ranks the MBA program tied for 30th in America. Fisher’s Executive MBA program was ranked third nationally for return on investment by The Wall Street Journal in 2008, citing a 170 percent return on an average of $66,900 invested in tuition and expenses during the 18-month program.
The Ohio State linguistics department was recently ranked among the top 10 programs nationally, and top 20 internationally by QS World University Rankings.
Ohio State’s research expenditures for the 2019 fiscal year were $968.3 million. The university is among the top 12 U.S. public research universities and third among all universities in industry-sponsored research (National Science Foundation). It is also named as one of the most innovative universities in the nation (U.S. News & World Report) and in the world (Reuters). In a 2007 report released by the National Science Foundation, Ohio State’s research expenditures for 2006 were $652 million, placing it seventh among public universities and 11th overall, also ranking third among all American universities for private industry-sponsored research. Research expenditures at Ohio State were $864 million in 2017. In 2006, Ohio State announced it would designate at least $110 million of its research efforts toward what it termed “fundamental concerns” such as research toward a cure for cancer, renewable energy sources and sustainable drinking water supplies. In 2021, President Kristina M. Johnson announced the university would invest at least $750 million over the next 10 years toward research and researchers. This was announced in conjunction with Ohio State’s new Innovation District, which will be an interdisciplinary research facility and act as a hub for healthcare and technology research, serving Ohio State faculty and students as well as public and private partners. Construction is expected to be completed in 2023.
Research facilities include Aeronautical/Astronautical Research Laboratory, Byrd Polar Research Center, Center for Automotive Research (OSU CAR), Chadwick Arboretum, Biomedical Research Tower, Biological Sciences Building, CDME, Comprehensive Cancer Center, David Heart and Lung Research Institute, Electroscience Laboratory, Large Binocular Telescope (LBT, originally named the Columbus Project), Mershon Center for International Security Studies, Museum of Biological Diversity, National Center for the Middle Market, Stone Laboratory on Gibraltar Island, OH, Center for Urban and Regional Analysis and Ohio Agricultural Research and Development Center.
Ohio State’s faculty currently includes 21 members of the National Academy of Sciences or National Academy of Engineering, four members of the Institute of Medicine and 177 elected fellows of the American Association for the Advancement of Science. In 2009, 17 Ohio State faculty members were elected as AAAS Fellows. Each year since 2002, Ohio State has either led or been second among all American universities in the number of their faculty members elected as fellows to the AAAS.
In surveys conducted in 2005 and 2006 by the Collaborative on Academic Careers in Higher Education (COACHE), Ohio State was rated as “exemplary” in four of the seven measured aspects of workplace satisfaction for junior faculty members at 31 universities: overall tenure practices, policy effectiveness, compensation and work-family balance.
In the last quarter century, 32 Ohio State faculty members have received the Guggenheim Fellowship, more than all other public and private Ohio universities combined. In 2008, three Ohio State faculty members were awarded Guggenheim Fellowships, placing Ohio State among the top 15 universities in the United States. Since the 2000–2001 award year, 55 Ohio State faculty members have been named as Fulbright Fellows, the most of any Ohio university.
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