Discovery of Exotic Particles Pentaquark
7:22 AM |
New particles consisting of five quarks (precisely four quarks and one anti-quark) were discovered after their existence was confirmed by five separate experiments around the world. Is a group of physicists working in SPRING-8 laboratory in Osaka, Japan, who first observed particles of mass 1.54 giga electronvolt (about one and a half times the mass of protons).
Their findings are published in Physical Review Letters, one of America's leading physics journals, last month. Not so long ago, the experiment was successfully confirmed by the DIANA research collaboration in Russia and the CLAS collaboration at Jefferson Lab, Virginia, USA. Finally, the collaboration of HERMES research at the DESY lab in Hamburg, Germany, and the SAPHIR collaboration in Bonn, Germany, also reported the same thing. Last month BBC online and the daily USA Today also carried this shocking news.
This discovery of course has serious consequences on the human view of the universe, because so far the quarks that are the foundation of the universe are known to form only subatomic particles in a combination of two or three quarks
Read also: Transverse and Longitudinal Waves
Quarks can only live in subatomic particles such as protons, neutrons, or pawns. The strong force that binds the quark inside the particle will grow larger if we want to remove it. Nevertheless, experimental results over the past 40 years have shown that the existence of quarks is no longer an impossible task.
To date there are six types of quarks named up, down, strange, charm, bottom, and top (u, d, s, c, b and t). Together with lepton and the interaction particles (gauge-boson), these six quarks constitute the universe we live in, including ourselves. The two lightest quarks are quark up and down. Both are proton and neutron constituents that build the majority of the universe.
A third type of quark is called a quark strange because it is always present in particles that have peculiar numbers such as kaon and hyperon.
In 1974 at the center of the linear accelerator Stanford (SLAC) found quark charm inside a new particle called Psi. Simultaneously in the national laboratory this type of Brookhaven quark is found in particles they call J. The particles now known as the J / Psi particles are a combination of quark charm and anti-charm (cc).
The fifth quark is the beauty or bottom that was first identified in Fermi's national laboratory (Fermilab) in 1977. In the same place in 1995 found the last type of quark named top or truth. This type is the most massive quark, weighing about 190 times the weight of a proton.
Exotic pentaquark particles are composed by two quark ups, two quark downs, and one quark anti-strange. This combination of uudds produces the same charge as the proton charge, but has an odd number one, and is identical to the positive K+ ion system and the K+n neutron. Not surprisingly, in their publications, the SPRING-8 collaboration states that their findings can be translated as quark uudds systems or K+n particle systems.
The presence of pentaquark particles is shown by a peak on the mass spectrum distribution lost in the process. This phenomenon is often encountered in the case of resonance baryon particle research, but the width of the peak in the pentaquark case is much smaller than that of resonant particles. In the case of pentaquark peak width is only about 20 mega electronvolt, whereas for baryon resonance can reach 500 mega electronvolt. Consequently, pentaquark particles can live longer (10-20 seconds) compared to baryon resonance particles (about 10-10 seconds).
Production process of exotic pentaquark particles at laboratory SPRING-8, Osaka, Japan
In Jefferson, Virginia, laboratories, experiments use photons from bremstrahlung processes from high-energy kinetic electron beams. The photons are fired at the deuteron target. The result of this collision is a proton, a negatively charged kaon, and a pentaquark particle. As in the previous case, the pentaquark particles will soon decay and be detected by the CLAS detector. This process is illustrated in figure 2 which is clearly simpler than the previous process. In this case the presence of pentaquark particles is represented by a peak on the invariance mass distribution of the K+n particle system.
Currently, the topic of pentaquark particle research is a very hot topic. Dozens of theoretical research papers came up shortly after the first experiment was confirmed. Some experiments to produce these particles have also been proposed, namely through collisions between kaon and nucleons, photons with protons, and others.
Their findings are published in Physical Review Letters, one of America's leading physics journals, last month. Not so long ago, the experiment was successfully confirmed by the DIANA research collaboration in Russia and the CLAS collaboration at Jefferson Lab, Virginia, USA. Finally, the collaboration of HERMES research at the DESY lab in Hamburg, Germany, and the SAPHIR collaboration in Bonn, Germany, also reported the same thing. Last month BBC online and the daily USA Today also carried this shocking news.
Discovery of Exotic Particles Pentaquark
So new, the name of particles that are charged with this positron is still not agreed. Some physicists still refer to it as a Z + particle, while lately it has mostly declared it as Theta + or exotic pentaquark particles (five quarks). Although not banned by the Standard Model officially embraced by all physicists, the presence of pentaquark particles has been difficult to detect. However, the rapid progress in the accelerator world and the increasingly sophisticated particle detectors are now ending the hunt for the particles that have been forecasted since about 30 years ago.
This discovery of course has serious consequences on the human view of the universe, because so far the quarks that are the foundation of the universe are known to form only subatomic particles in a combination of two or three quarks
What is a Quark?
Originally a quark was predicted by Murray Gell-mann and George Zweig as fundamental particles in 1964. The quark name was chosen by Gell-Mann. The name appears in James Joyce's novel Finnegan's Wake in one sentence: "three quarks for Muster Mark". This idea is very revolutionary because it introduces new sub-particles that are charged with +2/3 and -1/3 proton charge. But at first he was only considered a particle of mathematical fiction because the quark was never in a state of freedom.Read also: Transverse and Longitudinal Waves
Quarks can only live in subatomic particles such as protons, neutrons, or pawns. The strong force that binds the quark inside the particle will grow larger if we want to remove it. Nevertheless, experimental results over the past 40 years have shown that the existence of quarks is no longer an impossible task.
To date there are six types of quarks named up, down, strange, charm, bottom, and top (u, d, s, c, b and t). Together with lepton and the interaction particles (gauge-boson), these six quarks constitute the universe we live in, including ourselves. The two lightest quarks are quark up and down. Both are proton and neutron constituents that build the majority of the universe.
A third type of quark is called a quark strange because it is always present in particles that have peculiar numbers such as kaon and hyperon.
In 1974 at the center of the linear accelerator Stanford (SLAC) found quark charm inside a new particle called Psi. Simultaneously in the national laboratory this type of Brookhaven quark is found in particles they call J. The particles now known as the J / Psi particles are a combination of quark charm and anti-charm (cc).
The fifth quark is the beauty or bottom that was first identified in Fermi's national laboratory (Fermilab) in 1977. In the same place in 1995 found the last type of quark named top or truth. This type is the most massive quark, weighing about 190 times the weight of a proton.
Exotic pentaquark particles are composed by two quark ups, two quark downs, and one quark anti-strange. This combination of uudds produces the same charge as the proton charge, but has an odd number one, and is identical to the positive K+ ion system and the K+n neutron. Not surprisingly, in their publications, the SPRING-8 collaboration states that their findings can be translated as quark uudds systems or K+n particle systems.
Invention of Pentaquark Particles
In the SPRING-8 laboratory pentaquark particles were observed through the following experimental sequences. A beam of laser light is dissipated in an electron beam that has an 8 giga electronvolt energy circulating in a synchrotron. This scatter produces photons with a high enough energy which is then pounded on a target containing carbon. The result of this collision is a negatively charged charge, proton, pentaquark particles which in a relatively short time (between 10-20 seconds) will decay into a positively charged canton and a neutron, as well as the remains of other collisions. All the particles produced are captured by the detector as shown in Figure 1.
The presence of pentaquark particles is shown by a peak on the mass spectrum distribution lost in the process. This phenomenon is often encountered in the case of resonance baryon particle research, but the width of the peak in the pentaquark case is much smaller than that of resonant particles. In the case of pentaquark peak width is only about 20 mega electronvolt, whereas for baryon resonance can reach 500 mega electronvolt. Consequently, pentaquark particles can live longer (10-20 seconds) compared to baryon resonance particles (about 10-10 seconds).
Production process of exotic pentaquark particles at laboratory SPRING-8, Osaka, Japan
In Jefferson, Virginia, laboratories, experiments use photons from bremstrahlung processes from high-energy kinetic electron beams. The photons are fired at the deuteron target. The result of this collision is a proton, a negatively charged kaon, and a pentaquark particle. As in the previous case, the pentaquark particles will soon decay and be detected by the CLAS detector. This process is illustrated in figure 2 which is clearly simpler than the previous process. In this case the presence of pentaquark particles is represented by a peak on the invariance mass distribution of the K+n particle system.
Currently, the topic of pentaquark particle research is a very hot topic. Dozens of theoretical research papers came up shortly after the first experiment was confirmed. Some experiments to produce these particles have also been proposed, namely through collisions between kaon and nucleons, photons with protons, and others.
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