Scientists discover new kind of particle: the pentaquark

Updated 14 July 2015
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Scientists discover new kind of particle: the pentaquark

GENEVA: Scientists at the Large Hadron Collider in Switzerland have discovered a new kind of particle called the pentaquark, they announced Tuesday.
Physicists had theorized the existence of the pentaquark since the 1960s, but had never been able to prove it until its detection by the LHCb experiment at the LHC, the world’s most powerful particle smasher.
The discovery of the pentaquark comes after the LHC was used in 2012 to prove the existence of another particle, the Higgs Boson, which confers mass.
LHCb spokesman Guy Wilkinson said the pentaquark represented a way to combine quarks — the sub-atomic particles that make up protons and neutrons — “in a pattern that has never been observed before in over 50 years of experimental searches.”
He added: “Studying its properties may allow us to understand better how ordinary matter, the protons and neutrons from which we’re all made, is constituted.”
The LHC cranked back up again in June after a two-year upgrade, with scientists hailing a “new era” in their quest to unravel more mysteries of the Universe.
The new tests at the European Organization for Nuclear Research (CERN) have twice the energy levels they had during the last three-year experiment phase, when the existence of the Higgs Boson was confirmed.
Four laboratories are located along the LHC’s ring-shaped tunnel around a hundred meters underground, where scientists analyze collisions between particles moving at close to the speed of light.
The LHCb, one of the four experiments, is focused on understanding the differences between matter and anti-matter and analyzing certain quarks.
“Our understanding of the structure of matter was revolutionized in 1964 when American physicist, Murray Gell-Mann, proposed that a category of particles known as baryons, which includes protons and neutrons, are comprised of three fractionally charged objects called quarks,” CERN said in a statement.
Gell-Mann, who won the Nobel Physics Prize in 1969, further proposed another category of particles, mesons, formed of “quark-antiquark” pairs.
His model allowed for the existence of other quark combinations — such as pentaquarks, which are composed of four quarks and an antiquark. But no conclusive evidence for pentaquarks had been seen until now.
The LHCb experiment changed the game by allowing scientists to “look for pentaquarks from many perspectives,” CERN said.
The findings have been submitted to the journal Physical Review Letters.
The next stage of the research will focus on studying how the quarks are bound together within the pentaquarks, the nuclear laboratory added.


NASA scraps all-women spacewalk for lack of well-fitting suits

In this file photo taken on March 14, 2019 NASA astronauts Christina Hammock Koch and Nick Hague, members of the International Space Station (ISS) expedition 59/60, react shortly before the launch onboard the Soyuz MS-12 spacecraft from the Russian-leased Baikonur cosmodrome in Kazakhstan. (AFP)
Updated 26 March 2019
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NASA scraps all-women spacewalk for lack of well-fitting suits

  • The spacesuits aboard the ISS are in fact assemblies of several parts put together as best adapted to each astronaut’s body, explained Brandi Dean, spokeswoman of the Johnson Space Center in Houston

WASHINGTON: The US space agency NASA scrapped Monday a planned historic spacewalk by two women astronauts, citing a lack of available spacesuits that would fit them at the International Space Station.
Christina Koch will now perform tasks in space Friday with fellow American Nick Hague — instead of Anne McClain as originally planned.
Had Koch and McClain done their spacewalk together, it would have been the first ever by two women astronauts.
Until now, male-only or mixed male-female teams had conducted spacewalk since the space station was assembled in 1998 — 214 spacewalks until now.
McClain worked outside the station last week — with Hague — when she realized that a “medium“-sized upper half of her spacesuit fit her better.
“Because only one medium-size torso can be made ready by Friday, March 29, Koch will wear it,” NASA explained.
The spacesuits aboard the ISS are in fact assemblies of several parts put together as best adapted to each astronaut’s body, explained Brandi Dean, spokeswoman of the Johnson Space Center in Houston, Texas where American astronauts are based.
She said two upper parts in each of the three available spacesuit sizes are currently held at the ISS: medium, large and extra large.
“We do our best to anticipate the spacesuit sizes that each astronaut will need, based on the spacesuit size they wore in training on the ground, and in some cases astronauts train in multiple sizes,” she said in explaining the problem that hampered Friday’s planned spacewalk.
“However, individuals’ sizing needs may change when they are on orbit, in response to the changes living in microgravity can bring about in a body.
“In addition, no one training environment can fully simulate performing a spacewalk in microgravity, and an individual may find that their sizing preferences change in space.”