MSU physicist’s subatomic structure study published in Nature

Contact: Sarah Nicholas

STARKVILLE, Miss.—A member of Mississippi State’s Department of Physics and Astronomy has been recognized on an international platform for her investigation into the subatomic structure of nuclei.

Assistant Professor Lamiaa El Fassi’s research, “Probing high-momentum protons and neutrons in neutron-rich nuclei,” was published recently in the global scientific journal Nature.

Part of a large collaboration with more than 180 scientists from 45 institutions worldwide, El Fassi’s work is supported in part by the U.S. Department of Energy Office of Science and the Jefferson Lab. MSU’s Office of Research and Economic Development and the Department of Physics and Astronomy provided initial startup funds.

Conducted at the Department of Energy’s Thomas Jefferson National Accelerator Facility (Jefferson Lab) in Newport News, Virginia, El Fassi investigated highly energetic neutrons and protons which are known to pair together inside the nucleus for very short amounts of time.

Assisting El Fassi with this research were Md Latiful Kabir, physics and astronomy postdoctoral research associate stationed at Jefferson Lab, as well as Krishna Adhikari, postdoctoral associate at Jefferson Lab from 2014-2017.

Her research confirmed that even in neutron-rich nuclei, minority protons on average are more active – and faster – than majority neutrons. To read the complete abstract, visit

The results “not only help us understand how atomic nuclei are held together but also shed light on the smallest and densest extraterrestrial objects – the neutron stars,” El Fassi said, which “could lead to a better understanding of how the neutron stars are formed and how their tiny fraction of protons could affect their behavior and fate.”

Mark Novotny, department head, said the analysis results help scientists better comprehend the behavior of atomic nuclei but also reveal how much work remains for the scientific community to grasp how nucleons function.

“The experiment is about nuclear physics – why should you care?  By mass you are about 99.997 percent nuclear matter. If you put all the nuclear matter you are made of into one sphere, it would have a diameter comparable to the width of a human hair. As you can imagine from these numbers, nuclear matter behaves very strangely,” Novotny said. 

“The data-mining reanalysis of this experiment finds a result which, as the abstract states, ‘is surprising.’ That is the way science works,” he added.

El Fassi served as the lead data expert and reviewer on the data mining project which was a spin-off of her original previously published thesis results. 

She said this is not the end of the story, but rather “the beginning of a series of experiments that are scheduled to run after the completion of the Jefferson Lab beam energy upgrade.”

Associate Dean for Research Giselle Thibaudeau said El Fassi is making contributions to the research enterprise at MSU, both nationally and globally.

“El Fassi’s experiments and findings get us closer to understanding what goes on in the complex subatomic structure of the nucleus,” Thibaudeau said. “These results enable scientists to make better assumptions, models and predictions about the behavior and dynamics of atomic nuclei in terms of their building blocks – nucleons.”

El Fassi said her research is reaching a wider audience and attracting attention of those in other scientific fields because Nature articles are directed toward a general reader.

Reaching a varied audience is unusual in her field, El Fassi said, noting the recognition is “very beneficial since it provides wider recognition for scientists, institutions, collaborations, national labs or user facilities carrying out the research, and the funding agencies that are supporting it.”

For 14 decades, Nature has published top-quality peer-reviewed research in all fields of science.  For more information, visit

El Fassi joined MSU in 2014 as an experimental nuclear physicist. She is actively studying the internal structure of strongly interacting particles – hadrons – at Jefferson Lab and Fermi National Laboratory (Fermilab), in Batavia, Illinois.

El Fassi received her Ph.D. in 2008 from Mohammed V University in Rabat Morocco jointly with Argonne National Laboratory in Lemont, Illinois. She joined the ANL medium energy physics group for a graduate fellowship, conducting her thesis project experiment at Jefferson Lab from 2003-2004. El Fassi credits numerous mentors and thesis advisor Kawtar Hafidi – also from El Fassi’s home country of Morocco – for her move to the U.S. to study a topic not actively researched in their native country.

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Wednesday, October 10, 2018 - 11:38 am