How are hadrons born at the huge energies available in the LHC?

How are hadrons born at the huge energies available in the LHC?
Particles produced during one of the collisions of two protons, each with energies of 7 TeV, registered by the detectors of the LHCb experiment in 2011; view from two different sides. Credit: CERN, LHCb

Our world consists mainly of particles built up of three quarks bound by gluons. The process of the sticking together of quarks, called hadronisation, is still poorly understood. Physicists from the Institute of Nuclear Physics Polish Academy of Sciences in Cracow, working within the LHCb Collaboration, have obtained new information about it, thanks to the analysis of unique data collected in high-energy collisions of protons in the LHC.

When protons accelerated to the greatest energy collide with each other in the LHC, their component particles - quarks and gluons - create a puzzling intermediate state. The observation that in the collisions of such relatively simple particles as protons this intermediate state exhibits the properties of a liquid, typical for collisions of much more complex structures (heavy ions), was a big surprise. Properties of this type indicate the existence of a new state of matter: a quark-gluon plasma in which quarks and gluons behave almost as free particles. This exotic liquid cools instantly. As a result, the quarks and gluons re-connect with each other in a process called hadronisation. The effect of this is the birth of hadrons, particles that are clumps of two or three quarks. Thanks to the latest analysis of data collected at energies of seven teraelectronvolts, researchers from the Institute of Nuclear Physics Polish Academy of Sciences (IFJ PAN) in Cracow, working within the LHCb Collaboration, acquired new information on the mechanism of hadronisation in proton-proton collisions.

"The main role in proton collisions is played by strong interaction, described by the quantum chromodynamics. The phenomena occurring during the cooling of the are, however, so complex in terms of computation that until now it has not been possible fully understand the details of hadronisation. And yet it is a process of key significance! It is thanks to this that in the first moments after the Big Bang, the dominant majority of particles forming our everyday environment was formed from and gluons," says Assoc. Prof. Marcin Kucharczyk (IFJ PAN).

In the LHC, hadronisation is extremely fast, and occurs in an extremely small area around the point of proton collision: its dimensions reach only femtometres, or millionths of one billionth of a metre. It is no wonder then, that direct observation of this process is currently not possible. To obtain any information about its course, physicists must reach for various indirect methods. A key role is played by the basic tool of quantum mechanics: a wave function whose properties are mapped by the characteristics of particles of a given type (it is worth noting that although it is almost 100 years since the birth of quantum mechanics, there still exists various interpretations of the wave function!).

"The wave functions of identical particles will effectively overlap, i.e. interfere. If they are enhanced as a result of interference, we are talking about Bose-Einstein correlations, if they are suppressed - Fermi-Dirac correlations. In our analyses, we were interested in the enhancements, that is, the Bose-Einstein correlations. We were looking for them between the pi mesons flying out of the area of hadronisation in directions close to the original direction of the colliding beams of protons," explains Ph.D. student Bartosz Malecki (IFJ PAN).

The method used was originally developed for radioastronomy and is called HBT interferometry (from the names of its two creators: Robert Hanbury Brown and Richard Twiss). When used with reference to particles, HBT interferometry makes it possible to determine the size of the area of hadronisation and its evolution over time. It helps to provide information about, for example, whether this area is different for different numbers of emitted particles or for their different types.

The data from the LHCb detector made it possible to study the hadronisation process in the area of so-called small angles, i.e. for hadrons produced in directions close to the direction of the initial proton beams. The analysis performed by the group from the IFJ PAN provided indications that the parameters describing the source of hadronisation in this unique region covered by LHCb experiment at LHC are different from the results obtained for larger angles.

"The analysis that provided these interesting results will be continued in the LHCb experiment for various collision energies and different types of colliding structures. Thanks to this, it will be possible to verify some of the models describing hadronisation and, consequently, to better understand the course of the process itself," sums up Prof. Mariusz Witek (IFJ PAN).

The work of the team from the IFJ PAN was financed in part by the OPUS grant from the Polish National Science Centre.

The Henryk Niewodniczanski Institute of Nuclear Physics (IFJ PAN) is currently the largest research institute of the Polish Academy of Sciences. The broad range of studies and activities of IFJ PAN includes basic and applied research, ranging from particle and astrophysics, through hadron physics, high-, medium-, and low-energy , condensed matter physics (including materials engineering), to various applications of methods of nuclear physics in interdisciplinary research, covering medical physics, dosimetry, radiation and environmental biology, environmental protection, and other related disciplines. The average yearly yield of the IFJ PAN encompasses more than 600 scientific papers in the Journal Citation Reports published by the Thomson Reuters. The part of the Institute is the Cyclotron Centre Bronowice (CCB) which is an infrastructure, unique in Central Europe, to serve as a clinical and research centre in the area of medical and nuclear physics. IFJ PAN is a member of the Marian Smoluchowski Krakow Research Consortium: "Matter-Energy-Future" which possesses the status of a Leading National Research Centre (KNOW) in physics for the years 2012-2017. The Institute is of A+ Category (leading level in Poland) in the field of sciences and engineering.


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A very special run for the LHCb experiment

More information: R., Adeva, B. et al., Bose-Einstein correlations of same-sign charged pions in the forward region in pp collisions at s = 7 $$ sqrt{s}=7 $$ TeV, Journal of High Energy Physics (2017). DOI: 10.1007/JHEP12(2017)025
Provided by The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences
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Mar 01, 2018
particles don't exist

Mar 01, 2018
This exotic liquid cools instantly.


This is the kind of mistake I expect to see in a popular science magazine, not an article for physorg. ALL processes take a finite amount of time and one thing is for sure, no matter how fast the liquid cools it does not do so instantly.

Mar 01, 2018
Charge an the field are a unique object. Charge is the field center. No particles, you are measuring wiggles in the fields. Stop, that tickles!


Mar 02, 2018
This is the kind of mistake I expect to see in a popular science magazine, not an article for physorg. ALL processes take a finite amount of time and one thing is for sure

It's a bit tricky on the QM scale where you don't deal with time so much but with probabilities. if you have the a high probability for a state transition happening then the average time for this transition to occur from the precursor elements is very low.
Hadronization uses virtual particles from the vacuum to form bonds with any free quarks/gluons (i.e. the partner particles are always 'there') - so technically it is possible that no time (as we would think of it) elapses.

Mar 02, 2018
This is the kind of mistake I expect to see in a popular science magazine, not an article for physorg. ALL processes take a finite amount of time and one thing is for sure

It's a bit tricky on the QM scale where you don't deal with time so much but with probabilities. if you have the a high probability for a state transition happening then the average time for this transition to occur from the precursor elements is very low.
Hadronization uses virtual particles from the vacuum to form bonds with any free quarks/gluons (i.e. the partner particles are always 'there') - so technically it is possible that no time (as we would think of it) elapses.

its been 100 years of well documented nonsense. This, no exception, so I reject whatever it is your trying to insist upon.

Mar 02, 2018
Dear Hyped, since you admit that you do not understand anti-up's commentary. How can you ethically justify your criticism of their comment?

Mar 02, 2018
Dear Hyped, since you admit that you do not understand anti-up's commentary. How can you ethically justify your criticism of their comment?

Cause it's nonsense, false premise, anyway, i don't remember saying that i did not understand

Mar 04, 2018
@Hyperfuzzy: Atom (particle) theory is scientifically as old as stoichometry of chemists, and scientists agree that Einstein tested it successfully with an independent experiment [https://en.wikipe...c_theory ]. And you can see particle tracks in the data image of figure 2.

So this *conclusion* is not a false "premise".

And the observation that you do admit to not understanding is based on your description of "whatever" instead of, say "everything". Which still would be a failure of you understanding basic physics.

Mar 04, 2018
@Hyperfuzzy: Atom (particle) theory is scientifically as old as stoichometry of chemists, and scientists agree that Einstein tested it successfully with an independent experiment [https://en.wikipe...c_theory ]. And you can see particle tracks in the data image of figure 2.

So this *conclusion* is not a false "premise".

And the observation that you do admit to not understanding is based on your description of "whatever" instead of, say "everything". Which still would be a failure of you understanding basic physics.

Theory is without logic, theory ignores basics. A neutron is two opposite charge centers at 1 point. Known since the turn of the 20th century. Modern Theory is science fiction and these people have PhD's in bull$hit! No particles, no big bang, no GR, etc.. Do you require a lesson in Maxwell, Coulomb?

Mar 04, 2018
Wow, so there are commentators who don't have hyperfuzzy on ignore?

Mar 05, 2018
Again it is clear that science does not understand the structure of the universe, nor does it know how matter arises and from which it forms. Most scientists are so strongly contaminated with the wrong theories that they will never know the true causes of the phenomenon in the universe because they have also discarded the knowledge of their existence and of the one who formed them.
If you want to find out the truth, for which you are searching for hundreds of years in vain, accept what I write:
The substance is formed from the substance Aether, which fills the infinite universe.
This is achieved by the high vibrations of Aether, when strings are formed in three spatial directions, and in their cross sections matter is formed in two "aggregate" states. The "solid" state is 3KG particles (3 quarks and 3 gluon binders). This state of affairs, with Aether, has a connection that is expressed as gravity.

Mar 05, 2018
The second state is a "fluid" state-free gluon (annihilation of the positron neutron). This state of Aether is caused by the appearance of magnetism.
Gentlemen, all this is explained, which science has not been able to find out to date.
These "new" particles in particle collisions do not originate from "dead" protons, but scientists "have irritated the empty space in the tubes, which is Aether, which is" stirred "by a large magnetic field and a high velocity of movement. But these are only "deadborne abortions" performed by unconscious scientists.
THANK YOU AS MY COPYRIGHT, which one day must be accepted, whether you are rebelling or not !!

Mar 05, 2018
The vortex ring analogy also cannot explain, how the spin differs from charge, because it cannot distinguish between https://i.imgur.com/2tFaF0c.gif particles: all vortices in incompressible fluid are de-facto neutral, axially symmetric with no helicity, i.e. of integer spin. Whereas for to have charged particle, the vortex must get torsion not only along axis, but also perpendicularly in radial direction. This introduces extradimension in motion symmetry, which incompressible fluids have not available.

There are only these diametrical spherical fields, that extend from the center to infinity. Any motion causes a sinusoidal, non sinusoidal, event, are only within each unique field, they occupy all space and are immortal. The center is a conceptual point. The field occupies no space; therefore, particles do not exist!

Mar 07, 2018
How a particle or body gets its own spin. Here's how to deal with this! In the case of elliptical motion (also for other conic sections), part of the kinetic energy of radial velocity, it is transformed into a coupling of two vectors (spins) rotating one around the other. It has its own spin in one direction, and it rotates around the center of mass on a sinusoidal radius, in the opposite direction, of the same size.
Kilico applies this, if science has the desire to learn it and prove it on celestial bodies. I proved it !!

Mar 07, 2018
its been 100 years of well documented nonsense. This, no exception, so I reject whatever it is your trying to insist upon.

What are you complaining about? There has been thousands of instances of "well documented nonsense" from you on this site.

Mar 07, 2018
its been 100 years of well documented nonsense. This, no exception, so I reject whatever it is your trying to insist upon.

What are you complaining about? There has been thousands of instances of "well documented nonsense" from you on this site.

Then ignore me. Apply Coulomb and Maxwell. I'm just a stupid Engineer. I'm sure theoreticians can do better. Sorry if you thought it was a complaint. I'm a TE, I only state the obvious!

Mar 09, 2018
its been 100 years of well documented nonsense. This, no exception, so I reject whatever it is your trying to insist upon.

What are you complaining about? There has been thousands of instances of "well documented nonsense" from you on this site.

Then ignore me. Apply Coulomb and Maxwell. I'm just a stupid Engineer. I'm sure theoreticians can do better. Sorry if you thought it was a complaint. I'm a TE, I only state the obvious!

a point has no spin
but who am i? or do i matter?


Mar 10, 2018
Try https://drive.goo...XPRU3FG, i.e my Reality

IF SERIOUS, SEE THAT EVERYTHING FOLLOWS! No mystery, except the extremely useful idea of charge as the center of its field! No need for the standard model or GR, or the Big Bang or the expanding universe. Everything follows logically! So theory based upon the reality of experimentation! Try Maxwell and Coulomb and if you want to argue this as nonsense you are not a scientist.

Mar 11, 2018
Try https://drive.goo...nXPRU3FG,]https://drive.goo...XPRU3FG,[/url] i.e my Reality

https://drive.goo...nXPRU3FG

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