Pretty and Twice Strange: A New Elementary Particle

6 varieties of quarks are the most elementary of elementary particles. Protons and neutrons are built from the upper (u-quark) and lower (d-quark) quarks, and the amazing open particle is made up of 2 strange (s-quarks) and 1 lovely (b-quarks) quarks

The decay of a b-quark-containing particle resembles a firework: before it dies, it manages to fly no more than 1 mm - and then goes into other particles, J / Psi and omega-minus baryons. J / Psi also decay quickly, forming a pair of muons, and the omega-minus-baryon can “stretch” as many as several centimeters before turning into an unstable lambda baryon (decaying into a proton and pion) and into a long-lived particle - kaon

The Tevatron accelerator accelerates protons and antiprotons to speeds close to light. As a result of their collision, particles are formed, masses larger than those and others combined: energy passes into mass

DZero detector in height - like a three-story house. It captures traces of fast-living particles formed during collisions of high-energy particles - for example, proton-antiproton pairs

The "relatives" of the particle, dubbed Ωb ("omega-b"), baryons, are easily detected in nature. These include the well-known proton and neutron, but omega-b weighs six times heavier than them. It carries and a charge equal to the charge of an electron, has a spin ½.

Like other baryons, it includes 3 quarks, but their combination is unique for each type of baryon: for example, a proton consists of one d-quark (lower) and two u-quarks (upper), and omega-b - from one b- quark (lovely) and two s-quarks (strange). This discovery is, of course, tremendously important, because the particle closes the “gap” in a kind of “elementary table of elementary particles” - baryons, the main building blocks of ordinary matter.

Omega-b is perhaps the most exotic of the baryons known today. Scientists needed to analyze the results of approximately one hundred trillion collisions of protons with antiprotons carried out in a huge Tevatron particle accelerator. And only 18 of them contained data on the appearance (and rapid decay) of this rare particle. It is extremely unstable and manages to fly literally a millimeter before decaying into other particles - the existence of this particle lasts literally a trillionth of a second.

“The discovery of this baryon, ” says Dmitry Denisov, working on the accelerator, “is another triumph of the quark model. "Experimental data on its mass and decay will allow a better understanding of the forces that hold the quarks together." The quark model proposed in the early 1960s suggests that 20 baryons can be obtained from all varieties of quarks in different combinations. So far, 13 of them have been opened. And “weirder” than the detected omega-b particles - only omega-minus, consisting immediately of 3 strange quarks.

The discovery of omega-b was made using the DZero detector, which employs more than 600 scientists from 90 organizations in 18 countries. Omega-b is the last in the list of baryons they discovered: a year earlier, the particle Ξb- was first recorded here, and in 2006 - Σb. But even greater hopes, of course, are assigned to the Large Hadron Collider, which we have already talked about in all details - from construction to science and songs (“Until the LHC has happened”).

According to the press release of Fermi Lab


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