Feeds

Boffins five quarks short of a sub-atomic particle

No joy in pentaquark hunt

  • alert
  • submit to reddit

Build a business case: developing custom apps

A theoretical sub-atomic particle reportedly discovered in 2003 doesn't exist after all, scientists have discovered. The elusive pentaquark - comprising five quarks - failed to put in an appearance during experiments at Thomas Jefferson National Accelerator Facility in Virginia specifically carried out to search for the little blighter.

The pentaquark was first mooted in 1997 by Russian researchers who "convinced an experimental team at a Japanese particle accelerator to look for the products expected when pentaquarks decay", New Scientist reports. The Japanese duly announced in 2003 that they had identified the particle.

The alleged discovery led to a bit of a pentaquark landrush, as other teams scoured previous data for evidence of the five-quark package. Shortly thereafter, "a dozen teams announced seeing the particle, with a couple of groups even claiming to have discovered two additional types of pentaquark".

Now, however, a team called the CLAS colloboration has been unable to find evidence for the pentaquark. It fired energetic photons at liquid hydrogen and - despite the experiment resembling a similar effort by German outfit SAPHIR which came up trumps - CLAS turned up a blank.

Indeed, there had been a certain amount of scepticism regarding the pentaquark before the latest findings. Various groups who claimed pentaquark-spotting success reported different masses for the particle. More alarmingly, as the NS puts it, "all of the measurements suggested the particle took about 100 times longer to decay than other particles of its mass - about 1.5 times the mass of a proton".

MIT theoretical physicist, Bob Jaffe, said: "The theory community - myself included - became rather troubled about the particle." Jaffe applauded CLAS's methodology, stating: "They put together a sophisticated experiment with high statistics. They watched for a long time and didn't see it - and they should have, if the pentaquark had been there."

Jaffe - who with his colleague Frank Wilczek won the 2004 Nobel Prize for Physics for their work on quarks - further admitted: "I'm actually delighted." The reason for his joy is it now appears that while the force which binds quarks together in mesons (two quarks) and protons and neutrons (three quarks) is so strong that quarks are "never found alone in nature", it's not enough to bind five quarks - a fact which should keep the theoretical boffins at their blackboards for a while. ®

Related stories

Scientists explain why stuff is matter
Strange but charming new particle found
Scientists brew up 'missing link' isotope

Securing Web Applications Made Simple and Scalable

More from The Register

next story
World Solar Challenge contender claims new speed record
One charge sees Sunswift travel 500kms at over 100 km/h
SMELL YOU LATER, LOSERS – Dumbo tells rats, dogs... humans
Junk in the trunk? That's what people have
The Sun took a day off last week and made NO sunspots
Someone needs to get that lazy star cooking again before things get cold around here
Boffins discuss AI space program at hush-hush IARPA confab
IBM, MIT, plenty of others invited to fill Uncle Sam's spy toolchest, but where's Google?
Bad back? Show some spine and stop popping paracetamol
Study finds common pain-killer doesn't reduce pain or shorten recovery
Forty-five years ago: FOOTPRINTS FOUND ON MOON
NASA won't be back any time soon, sadly
Jurassic squawk: Dinos were Earth's early FEATHERED friends
Boffins research: Ancient dinos may all have had 'potential' fluff
prev story

Whitepapers

Designing a Defense for Mobile Applications
Learn about the various considerations for defending mobile applications - from the application architecture itself to the myriad testing technologies.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Top 8 considerations to enable and simplify mobility
In this whitepaper learn how to successfully add mobile capabilities simply and cost effectively.
Seven Steps to Software Security
Seven practical steps you can begin to take today to secure your applications and prevent the damages a successful cyber-attack can cause.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.