Newswise — A study is published in the journal of Nuclear Science and Techniques, researchers led by Prof. Hua Zheng from Shaanxi Normal University, heralding a significant breakthrough in high-energy particle physics. This study sheds new light on the behavior of particles in high-energy collisions, an area of research integral to deepening our understanding of the universe’s origins.

In this comprehensive study, the researchers implemented the Tsallis thermodynamics framework, utilizing the Tsallis distribution—a sophisticated extension of the Boltzmann-Gibbs distribution—to analyze the transverse momentum spectrum of particles in high-energy collisions. This innovative method considers particles detected in experiments as being produced by fireballs, which adhere to the Tsallis distribution, thereby providing a more detailed and nuanced understanding of particle dynamics in high-energy collision environments. Focusing on asymmetric collision systems, specifically p+Al, p+Au, and ³He+Au at 200 GeV, the team leveraged the fireball model rooted in Tsallis thermodynamics. This model proved effective in fitting the experimental data from these complex collision systems. A key aspect of the study was examining the total multiplicities of charged particles, particularly their relationship with the centrality of the collisions. The research also highlighted the significant impact of data quality, especially in terms of pseudo-rapidity distributions, on the overall findings. Further, the study delved deeply into the variations in fireball model parameters, analyzing how these parameters change with both the centrality and the size of the collision systems. This approach uncovered the intricate and complex dynamics characteristic of asymmetric collisions, contributing significantly to the field of high-energy particle physics.

This study’s findings confirm that the fireball model with Tsallis thermodynamics can be a universal framework to describe the pseudo-rapidity distribution of charged particles produced in asymmetric collision systems. The success of this model in fitting experimental data paves the way for more detailed studies into the complex dynamics of high-energy particle collisions. These insights are not only significant for theoretical physics but also have practical implications in particle accelerator experiments and the search for new elements and particles physics. The continued exploration of these complex systems will deepen our understanding of the universe’s fundamental processes.

References

DOI

10.1007/s41365-023-01334-9

Original Source URL

https://doi.org/10.1007/s41365-023-01334-9

Funding information

The National Natural Science Foundation of China (11905120, 11947416);
The Natural Science Foundation of Sichuan Province (2023NSFSC1322);
The Natural Science Basic Research Plan in Shaanxi Province of China (2023-JC-YB-012);
The United States Department of Energy (DE-FG02-93ER40773);
The NNSA (DENA0003841 (CENTAUR)).

About Nuclear Science and Techniques

Nuclear Science and Techniques (NST) reports scientific findings, technical advances and important results in the fields of nuclear science and techniques. The aim of this periodical is to stimulate cross-fertilization of knowledge among scientists and engineers working in the fields of nuclear research.

Journal Link: Nuclear Science and Techniques

Newswise — On the 164th anniversary of Charles Darwin’s Origin of species, the Darwin Online project at the National University of Singapore (NUS) will launch all the surviving draft pages of one of the most influential scientific books in history. After his book was published, the unsentimental Darwin discarded the hundreds of pages of the original handwritten draft of his epoch-making book into the Darwin family’s scrap paper pile. His children used some sheets for drawings and others were torn in half by one of Darwin’s son who used the blank back sides for mathematical exercises.

In the end, almost all of the draft pages were destroyed. Towards the end of Darwin’s life, his theory of evolution was more widely accepted and there was intense interest in the original draft of Origin of Species. Some were rescued from the piles of scrap paper and old notes and, over decades, many were given away as gifts especially by his children after his death. These draft pages are now dispersed around the world and some have probably been lost forever.

Discovering Darwin’s manuscripts

Today, the rough drafts of Darwin’s Origin of species are some of the most precious and valuable pieces of paper in the history of science worth almost a million dollars each. The last one to sell at auction, in 2018, went for £490,000 (approximately USD$ 600,000). The United Kingdom’s Minister for Arts, Heritage and Tourism placed an export bar on Darwin’s manuscript, due to its cultural and national significance, in hopes of keeping it in the country.

So far, about 50 sheets were known to survive. This launch of the drafts by Darwin scholar, Dr John van Wyhe from the NUS Department of Biological Sciences, includes seven draft pages not found in previous lists with three draft pages recently rediscovered – bringing the total to 59. This collection of draft pages includes unprecedented details about each sheet and its history. For example, one was donated by Darwin’s daughter Henrietta Litchfield to a Red Cross auction during WWI for the war wounded. It was purchased anonymously by cotton merchant and aviation pioneer Sir Alfred Paton who donated it to his old school, Clifton College. It was later sold at auction in 1999 for £39,500 to an anonymous buyer “in the Americas” and has never been seen again. Fortunately, it was photocopied by Clifton College and a photograph was printed in the auction catalogue.

Uncovering the mysteries behind Darwin’s drafts

Darwin’s handwriting is notoriously difficult to read. All of the drafts have been transcribed and edited showing where the text appears in the published book so they may be compared. The drafts make it possible to see in detail how Darwin originally composed and revised many of his arguments. The drafts total 11,700 words (7.7% of Origin of species) and contain many sentences that were never published, offering fascinating insights into Darwin’s thinking as he composed the book that changed the world. What would have happened if he had published the original version of some of his arguments? In one crossed out sentence, Darwin wrote that “An instinct may almost be called an empty trick.”

In a famous passage of the Origin of species, Darwin argued that natural selection could gradually transform an animal like a bear into something like a whale. He was mocked and criticised by reviewers so severely that he deleted the passage from all later editions. What would have happened if he had published the passage as originally written?

In one of the drafts, this never-printed paragraph was revealed as follows:

“In N. America a bear has been seen swimming for hours with widely open mouth, thus catching the minute crustaceans swimming on the surface. Even in so extreme a case as this, if the supply of minute crustaceans were constant, & there did not in the region exist better adapted competitors, I can see no difficulty in a race of Bears being rendered by natural selection more & more aquatic in habits & structure, with larger & larger mouth, till a creature was produced as monstrous in size & structure as a whale though feeding on prey so minute.”

Darwin later made very extensive corrections to the first and second proofs which makes the text of the first draft differ even more from the published book. His son Francis recalled that “my mother looked over the proofs of the ‘Origin.'”

The drafts can be viewed for free via a detailed illustrated introduction here. The link will be made live after the embargo is lifted.

The drafts join the world’s largest collection of Darwin’s writings, both publications and handwritten manuscripts, Darwin Online.

Retired NASA astronaut Mary Cleave, a veteran of two NASA spaceflights, died Nov. 27. She was 76. A scientist with training in civil and environmental engineering, as well as biological sciences and microbial ecology, Cleave was the first woman to serve as an associate administrator for NASA’s Science Mission Directorate.

Born in Southampton, New York, Cleave received a Bachelor of Science degree in biological sciences from Colorado State University, Fort Collins, in 1969, and Master of Science in microbial ecology and a doctorate in civil and environmental engineering, both from Utah State University, Logan, in 1975 and 1979, respectively.

“I’m sad we’ve lost trail blazer Dr. Mary Cleave, shuttle astronaut, veteran of two spaceflights, and first woman to lead the Science Mission Directorate as associate administrator,” said NASA Associate Administrator Bob Cabana. “Mary was a force of nature with a passion for science, exploration, and caring for our home planet. She will be missed.”

Cleave was selected as an astronaut in May 1980. Her technical assignments included flight software verification in the SAIL (Shuttle Avionics Integration Laboratory), spacecraft communicator on five space shuttle flights, and malfunctions procedures book and crew equipment design.

Cleave launched on her first mission, STS-61B, aboard space shuttle Atlantis on Nov. 26,1985. During the flight, the crew deployed communications satellites, conducted two six-hour spacewalks to demonstrate space station construction techniques, operated the Continuous Flow Electrophoresis experiment for McDonnell Douglas and a Getaway Special container for Telesat and tested the Orbiter Experiments Digital Autopilot.

Cleave’s second mission, STS-30, which also was on Atlantis, launched May 4, 1989. It was a four-day flight during which the crew successfully deployed the Magellan Venus exploration spacecraft, the first planetary probe to be deployed from a space shuttle. Magellan arrived at Venus in August 1990 and mapped more than 95% of the surface. In addition, the crew also worked on secondary payloads involving indium crystal growth, electrical storms, and Earth observation studies.

Cleave transferred from NASA’s Johnson Space Center in Houston to the agency’s Goddard Space Flight Center in Greenbelt, Maryland in May 1991. There, she worked in the Laboratory for Hydrospheric Processes as the project manager for SeaWiFS (Sea-viewing, Wide-Field-of-view-Sensor), an ocean color sensor which monitored vegetation globally.

In March 2000, she went to serve as deputy associate administrator for advanced planning in the Office of Earth Science at NASA’s Headquarters in Washington. From August 2005 to February 2007, Cleave was the associate administrator for NASA’s Science Mission Directorate where she guided an array of research and scientific exploration programs for planet Earth, space weather, the solar system, and the universe. She also oversaw an assortment of grant-based research programs and a diverse constellation of spacecraft, from small, principal investigator-led missions to large flagship missions.

Cleave’s awards included: two NASA Space Flight medals; two NASA Exceptional Service medals; an American Astronautical Society Flight Achievement Award; a NASA Exceptional Achievement Medal; and NASA Engineer of the Year.

Cleave retired from NASA in February 2007.

https://go.nasa.gov/3uDCykl

Source: NASA

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