New important discovery for physics made at CERN in Geneva. For the first time a particle consisting of four quarks has been identified (here the study signed by over 900 scientists). “What we discovered is special, because it is made up of four heavy quarks: two called charms and two anticharm”, explains Giovanni Passaleva, international manager of the LHCb experiment. “It therefore represents a privileged test bench for the development of theoretical models of strong interactions”.
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Tetraquark
The protons and neutrons that make up the nucleus of atoms consist of three quarks, which are even smaller particles, then there are the mesons which are composed of a quark and an antiquark linked together by “strong” force. In 2015 a particle consisting of 5 quarks (pentaquarks) was also discovered at CERN. To find the tetraquark it took decades of research to identify a few examples. “Particles defined as” exotic “made by four quarks have been known since 2013, by five quarks since 2015,” explains Passaleva. “But this is the first with four heavy quarks.”
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The Italian contribution
The identification of this new particle was carried out with the CERN LHC accelerator with a strong contribution from the Infn group (National Institute for Nuclear Physics) in Florence, which from the outset had the responsibility of carrying out the data analysis acquired over years and produced by collisions between protons accelerated almost at the speed of light. “Our detector is now undergoing a further transformation,” adds Matteo Palutan, Infn researcher of the National Laboratories of Frascati and international deputy manager of LHCb, “The enhancements will allow you to acquire a much greater amount of data than has been possible till now”.
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July 1, 2020 (change July 1, 2020 | 5:40 pm)
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