Physicists have discovered what looks like an entire family of new particles in the LHC

They can’t be explained by our existing laws of physics.

The new particles have been named X(4140), X(4274), X(4500), and X(4700) after their respective masses, and each one has been found to contain a unique combination of two charm quarks and two strange quarks. This makes them the first four-quark particles found to be composed entirely of heavy quarks, Symmetry reports.

By ‘exciting’ the individual quarks inside their new tetraquark particles, the researchers were able to observe their unique internal structure, mass, and quantum numbers. In doing so, they discovered something that doesn’t fit with current physics models that work with so-called ordinary particles, such as composite hadrons built from either a quark and an anti-quark, or three separate quarks, CERN reports.

Physics are now trying to come up with new models to explain their results.

The results have been published in two papers on the pre-print website arXiv.org here and here, so are now going to be scrutinised by independent physicists ahead of the formal peer-review process.

The team is expecting one of two possibilities to be confirmed with further research: theoretical psycists are either going to have to explain the existence of this new family of particles, or they could be idenfified as the result of strange ‘ripple effects’ emanating from never-before-seen behaviours of existing particles.

“The molecular explanation does not fit with the data,” Skwarnicki told Charley at Symmetry.

“But I personally would not conclude that these are definitely tightly bound states of four quarks. It could be possible that these are not even particles. The result could show the complex interplays of known particle pairs flippantly changing their identities.”

…………..

… what this article doesn’t mention is the possibility that DM might be a stable version of what they have found. Not that I am championing the assumption but it does seem an obvious question.

or you could ask, what are the properties of DM and how does it interact with the Universe. and, what particles are composed of quarks and how do these particles interact with the Universe. and see if there are any properties in common.

ChrispenEvan said:

or you could ask, what are the properties of DM and how does it interact with the Universe. and, what particles are composed of quarks and how do these particles interact with the Universe. and see if there are any properties in common.

I only got as far as observing they are heavy particles but yes that is an appropriate direction to take, thank you.

In regards to dark matter could all the empty space (?) between stellar objects account for our missing matter in the universe, if it was given a mass per certain area, say square light years (if such a thing exists)

DM is not evenly spread in the Universe. it tends to clump.

ChrispenEvan said:

DM is not evenly spread in the Universe. it tends to clump.

Around matter isn’t it, perhaps the further away from a gravitational influence you are the less it clumps, who knows

they have run simulations. which seem to be pretty accurate.

http://hipacc.ucsc.edu/Bolshoi.html

> Physicists have discovered what looks like an entire family of new particles in the LHC.

Excellent

> They can’t be explained by our existing laws of physics.

Agreed. Well, almost. Better to say “can’t yet be explained”. Tetra quarks require an extension to the existing law that quarks can only exist in pairs and triplets.

> The new particles have been named X(4140), X(4274), X(4500), and X(4700) after their respective masses, and each one has been found to contain a unique combination of two charm quarks and two strange quarks. This makes them the first four-quark particles found to be composed entirely of heavy quarks,

Are there other ones involving light quarks? (Checks wikipedia) Yes, X(3872) in 2003. “In 2007, Belle announced the observation of the Z(4430) state, a ccdu tetraquark candidate. In 2014, the Large Hadron Collider experiment LHCb confirmed the existence of the Z(4430) state with a significance of over 13.9 σ.”

> The results have been published in two papers on the pre-print website arXiv.org here and here, so are now going to be scrutinised by independent physicists ahead of the formal peer-review process.

http://arxiv.org/abs/1606.07895 and http://arxiv.org/abs/1606.07898

> “The molecular explanation does not fit with the data,”

ie. the new tetraquarks are not a “molecule” containing two two-quark mesons. That’s the first obvious possibility that needed to be ruled out.

> “But I personally would not conclude that these are definitely tightly bound states of four quarks. It could be possible that these are not even particles. The result could show the complex interplays of known particle pairs flippantly changing their identities.”

If not particles then they would be quasiparticles.

> … what this article doesn’t mention is the possibility that DM might be a stable version of what they have found. Not that I am championing the assumption but it does seem an obvious question.

My knee-jerk reaction is “can’t be dark matter because not stable”. But thinking further, without seeing a consistent theoretical treatment I can’t be absolutely certain that there isn’t a stable tetraquark.

> “The UDS is by far the deepest near-infrared survey over such a large, contiguous area (0.8 sq degrees). There is only one other similar survey, which is known as UltraVISTA. It covers a larger area (1.5 sq degree) but is not quite so deep. Together the UDS and UltraVISTA should revolutionize studies of the high-redshift Universe over the next few years.”

I knew of the UKIRT ultra-deep survey (UDS) but not of UltraVISTA. (Checks web) http://ultravista.org/

UltraVISTA:
Third data release (April 2016).
Second data release (Jan 2014).
First data release (Feb 2012).
Visible and Infrared Survey Telescope for Astronomy (VISTA) diameter 4.1 m, operation near-infrared, survey, location Paranal, first started operating in 2009.

Here’s VISTA, hiding away amongst the giant telescopes of the VLT.

Oops, wrong thread, I’d wondered where that post went to.

mollwollfumble said:

Oops, wrong thread, I’d wondered where that post went to.

You are human after all? ;)