What Are Quarks?

Updated on September 10, 2019
1701TheOriginal profile image

Leonard Kelley holds a bachelor's in physics with a minor in mathematics. He loves the academic world and strives to constantly explore it.

Source

Spin

In the middle of the 20th century, scientists were on the hunt for new particles in the standard Model of Particle Physics, and in an effort to do so they tried to arrange the known ones in an effort to uncover a pattern. Murray Geltmann (Caltech) and George Zweig independently of one another wondered if instead scientists should look at the subatomic and see what would be found there. And sure enough, there was: quarks, with fractional charges of +/- 1/3 or 2/3. Protons have 2 +2/3 and 1 -1/3 for a total of +1 charge, while neutrons combine to give zero. This alone is weird but it was favorable because it heled explain meson particle charges but for many years quarks were treated as a mathematical tool only, and not as a serious matter. And 20 years of experiments didn’t uncover them either. It wouldn’t be until 1968 that the SLAC experiment gave some evidence for their existence. It showed that the particle trails post collision of an electron and a proton were a total of three divergences, which is exactly the behavior the quarks would undergo! (Morris 113-4)

Quantum World

But quarks get stranger. The forces between quarks increase as distance does, not the inverse proportion we are used to. And energy that is poured into separating them can lead to new quarks being generated. Can anything hope to account for this strange behavior? Possibly, yes. Quantum electrodynamics (QED), the merging of quantum mechanics with electromagnetics, along with quantum chromodynamics (QCD), the theory behind the forces between quarks, were important tools in this quest. That QCD involves colors (not literally) in the form of red, blue, and green as ways to convey the exchange of gluons, which bind quarks together and therefore act as the force carrier for QED. On top of this, quarks also have spin up or spin down, so a total of 18 different quarks are known to exist (115-119).

Mass Issues

Protons and neutrons have a complicated structure that essentially amounts to quarks being held by binding energy. If one were to look at the mass profile for any of these, one would find that the mass would be 1% from the quarks and 99% from the binding energy holding the proton or neutron together! That is a nutty result, for it implies that most of the stuff that we are constituted from is just energy, with the “physical portion” consisting of just 1% of the total mass. But this is a consequence of the entropy that wants to be put into effect. We need a lot of energy to counteract this natural drive to disorder. We are more energy than quark or electron, and we have a preliminary answer as to the why but is there more to this? Like the relationship this energy has to inertia and gravity. Higgs Bosons and the hypothetical graviton are possible answers. But that Boson requires a Field to operate in and acts like inertia conceptually does. This viewpoint implies that it is inertia itself that causes mass instead of energy arguments! Different masses are just different interactions with the Higgs Field. But what differences would these be? (Cham 62-4, 68-71).

Quark-gluon plasma, visualized.
Quark-gluon plasma, visualized. | Source

Quark-Gluon Plasma

And if one can get two particles to collide at the right speed and angle, one can get a quark-gluon plasma. Yes, the collision can be so energetic that is breaks the bonds holding the atomic particles together just like how the early Universe was. This plasma has many fascinating properties including being the lowest viscosity fluid known, the hottest known fluid known, and had a vorticity of 1021 per second (similar to frequency). This lattermost property is tough to measure because of the energy and complexity of the mix itself but scientists looked at the resulting particles that formed form the cooled off plasma to determine the overall spin. This is important because it allows scientists to test out QCD and see which symmetry theory works best for it. One is chiral magnetic (if a magnetic field is present) and the other is chiral vortical (if spin is present). Scientists want to see if these plasmas can go from one type to the other, but no known magnetic fields around quarks have been seen yet (Timmer).

Tetraquark

What we haven’t talked about are quark pairings. Mesons can have two and baryons can have three, but four should be impossible. That is why scientists were surprised in 2013 when the KEKB accelerator found evidence for a tetraquark in a particle called Z(3900), which itself decayed from an exotic particle called Y(4260). At first the consensus was that it was two mesons orbiting each other while others felt it was two quarks and their antimatter counterparts in the same area. The tetraquark could offer scientists new ways to test QCD and see if it still needs revision, such as color neutrality (Wolchover, Moskowitz).

Possible pentaquark configurations.
Possible pentaquark configurations. | Source

Pentaquark

Surely that tetraquark should have been it in terms of interesting quark pairings, but think again. This time it was the LHCb detector at CERN that found evidence for it while looking at how certain baryons with an up, down and bottom quark behaved as it decayed. The rates where off from what theory predicted, and when scientists looked at models for the decay using computers, it showed a temporary pentaquark formation, with possible energies of 4449 MeV or 4380 MeV. As for the full structure of this, who knows. I'm sure like all these topics, it shall prove to be facinating… (CERN, Timmer “CERN”)

Works Cited

CERN. “Discovery of a new class of particles at the LHC.” Astronomy.com. Kalmbach Publishing Co., 15 Jul. 2015. Web. 24 Sept. 2018.

Cham, Jorge and Daniel Whiteson. We Have No Idea. Riverhead Press, New York, 2017. Print. 60-73.

Morris, Richard. The Universe, the Eleventh Dimension, and Everything. Four Walls Eight Windows, New York. 1999. Print. 113-9.

Moskowitz, Clara. “Four-Quark Subatomic Particle Seen in Japan and China May Be Entirely New Form of Matter.” Huffingtonpost.com. Huffington Post, 19 Jun. 2013. Web. 16 Aug. 2018.

Timmer, John. “CERN experiment spots two different five-quark particles.” Arstechnica.com. Conte Nast., 14 Jul. 2015. Web. 24 Sept. 2018.

---. “Taking quark-gluon plasma for a spin may unbreak a fundamental symmetry." Arstechnica.com. Conte Nast., 02 Aug. 2017. Web. 14 Aug. 2018.

Wolchover, Natalie. “Quark Quartet Fuels Quantum Feud.” Quantamagazine.org. Quanta, 27 Aug. 2014. Web. 15 Aug. 2018.

Questions & Answers

    © 2019 Leonard Kelley

    Comments

      0 of 8192 characters used
      Post Comment

      No comments yet.

      working

      This website uses cookies

      As a user in the EEA, your approval is needed on a few things. To provide a better website experience, owlcation.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

      For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://owlcation.com/privacy-policy#gdpr

      Show Details
      Necessary
      HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
      LoginThis is necessary to sign in to the HubPages Service.
      Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
      AkismetThis is used to detect comment spam. (Privacy Policy)
      HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
      HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
      Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
      CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
      Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
      Features
      Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
      Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
      Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
      Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
      Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
      VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
      PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
      Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
      MavenThis supports the Maven widget and search functionality. (Privacy Policy)
      Marketing
      Google AdSenseThis is an ad network. (Privacy Policy)
      Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
      Index ExchangeThis is an ad network. (Privacy Policy)
      SovrnThis is an ad network. (Privacy Policy)
      Facebook AdsThis is an ad network. (Privacy Policy)
      Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
      AppNexusThis is an ad network. (Privacy Policy)
      OpenxThis is an ad network. (Privacy Policy)
      Rubicon ProjectThis is an ad network. (Privacy Policy)
      TripleLiftThis is an ad network. (Privacy Policy)
      Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
      Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
      Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
      Statistics
      Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
      ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
      Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)
      ClickscoThis is a data management platform studying reader behavior (Privacy Policy)