Asymmetry in the production of matter and antimatter can interfere with neutrino detection

An experiment at CERN has shown that alluring mesons and their antimatter counterparts are not produced in perfectly equal proportions. Physicists from Krakow have proposed their own explanation for the phenomenon. What they came up with in their research could mess up neutrino researchers quite a bit.

In the first moments after the Big Bang, the Universe was filled with rów with higher quantities of particles and antiparticles. As it cooled, matter and antimatter began to combine and annihilate, turning into radiation. Why some of the matter from which theórej built today’s Universe, survived the conflagration? To decipher this great conundrum wspón modern science, physicists are trying to better understand any mechanisms responsible for even the smallest disparities in particle and antiparticle production.

A group of scientistsów from the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Krakow, Poland, associated with the LHCb experiment at the Large Hadron Colliderów (LHC) in Geneva, recently looked at one such processów: the asymmetry that occurs at the birth of mesonsów and antimesonów alluring. Conclusions from the analysis may have very tangible practical significance. The research was announced by the IFJ PAN in a message sent to PAP.

According to wspóAccording to modern knowledge, quarks are the most important indivisible bricks, from which theóof which matter is composed. They are known in six types: these are the quarks górne (u), bottom (d), strange (s), alluring (c), beautiful (b) and true (t), with each type also having itsój antimaterial counterpart (often denoted by a dash above the letter, read as „bar”).

Quarks in the ogó³ are formed in quark-antiquark pairs. They are extremely sociable particles: almost immediately after their creation, they bind into hadrons, i.e. ensembles of twoóch, three and sometimes more quarksów or anti-quarków, bonded by gluonów (that is, particles carrying strong nuclear interactions). The process of quark mergingów/antiquarkóin complexes is the so-called. hadronization.

Non-permanent hadrons made of quark-antiquark pairs have been called mesons. If in a meson któlynx with a quarków is alluring, the particle is referred to as an alluring meson and denoted by the letter D (or for an alluring anticaon: D with a dash). A pair made up of an alluring quark and a bottom quark is a D+ meson, and one made up of an alluring quark and a bottom quark is a D meson-.

Measurements over the past quarter century, including the recent LHCb experiment, have noted an interesting asymmetry in the. It turned out that D+ and D- mesons are not always produced in exactly the same proportions. In the case of processóin observed at the LHCb, initiated in collisions of counter-rotating proton beamsóIn high energies, the asymmetry was small, less than one percent.

„Alluring quarks are formed at the mainównie during gluon collisionsów, and after birth they hadronize into mesons D. We looked at a different mechanism of meson formationów, known as nonfavorite fragmentation of quarksów. The meson is formed here as a result of the interaction of some light quark – i.e. górny, bottom or strange – with its corresponding antiquark. With the help of nuanceóin such a mechanism, the asymmetry between kaons and anticaons, i.e. K+ and K mesons, was explained earlier-. So far, however, it has not been verified whether a similar mechanism mówould explain the asymmetry between the relatively massive D+ mesons and D-” – mówi Dr. Rafał Maciuła (IFJ PAN), first author of the publication in the journal „Physical Review D”.

Physics researchów of the IFJ PAN may have far-reaching consequences for observatorióIn neutrino detectors, such as the IceCube detector in Antarctica. This detector, conducted by 49 scientific institutions from 12 countriesów, using thousands of photomultipliers to monitor a cubic kilometer of ice located almost póone kilometer below the surface. Photomultipliers track subtle flashes of light, initiated by the interaction of particles forming lód with neutrinos, elementary particles interacting very weakly with ordinary matter.

IceCube records several hundred neutrinos per day. However, it is assumed that neutrinos with significant energies reached the detector directly from distant sources ofódeles of space: supernovae or merging black holes or neutron stars.

„Some of these processesów, resulting in the formation of neutrinos with high energies, takes place with the participation of mesonsóin D. Meanwhile, we show that the mechanism of production of these mesonsów in the atmosphere may be much more efficient than previously thought. Thus, if our conjecture is confirmed, some of the recorded high-energy neutrinos, now thought to be cosmic, have in fact originated just above our heads and are disrupting the real picture of events in deep space” – explains prof. dr hab. Antoni Szczurek (IFJ PAN).

The model proposed by the Cracow physicistsów has today the status of a hypothesis. However, the researchers propose how it can be verified. According to them, it would be enough in the LHC gas pedal to direct a single beam at a stationary disk.

Research on asymmetry in meson productionóin the alluring was financed from the funds of theóin the statutory activities of the IFJ PAN and a grant from the National Science Center.