A phenomenological feasibility study of the possible impact of the intrinsic heavy quark (charm) mechanism on the production of doubly heavy mesons and baryons

Abstract

Kui kõneldakse CERNi suurest hadronite põrgutist (LHC), siis on inimesed harjunud mõtlema Higgsi bosoni, tumeaine ja teiste mõistatuste peale. Need aga, kes on seotud teadusuuringutega põrgutitel, teavad, et LHC üks peamistest teemadest on uurida prootoni struktuuri. On teada, et peaaegu 100% meie massist ei ole nende aatomite mass, millest me koosneme, vaid mass on koondatud aatomite väiksesse ossa, mida nimetatakse tuumaks ja mis koosneb prootonitest ja neutronitest. Praegused füüsikalised eksperimendid keskenduvad peamiselt prootoni nendele koostisosadele, mis kannavad väikest osa prootoni impulsist, või nende koostisosade dünaamikale. Mõned eksperimentaalsed andmed siiski viitavad sellele, et ka prootoni suure impulsiga koostisosadel võib olla teatud roll. Seda on käsitletud nn. sisemise sarmi (IC) mudelis. Vastavate katseandmete tõlgendamine ei ole kahjuks selge, vaid on üpris spekulatiivne. Suurte impulssidega osade lõppseisundite seas on J/ψ meson, mis koosneb sarmi– antisarmi kvarkpaarist. J/ψ meson avastati 1971. aastal, aga selle tekkemehhanismid ei ole veel selged. Kasutades IC mudelit püuäme III peatükis leida NA3 (CERN) eksperimentaalsete andmete tõlgenduse. Samuti esitame teoreetilised alused COMPASSi (CERN) eksperimendi praeguste uuringute ja tulevaste AFTER@LHC eksperimentide õige tõlgenduse jaoks. SELEXi (Fermilab) kahekordse sarmiga barüonide tekke mõõtmised kuuluvad kaasaegse barüonfüüsika kõige väljakutsuvamate ja üllatavamate tulemuste hulka. Isegi kõige uuemad LHCb (CERN) tulemused ei anna selle mõistatuse lahendust. IV peatükis selgitame SELEXi andmeid IC abil. Arvatavasti on lugeja nüüd juba aru saanud, et andmete tõlgendamine on väga oluline. Alles hiljuti otsis LHCb kollaboratsioon oma andmetest tõendusi, mis kinnitaksid IC mudelit. Kahjuks on nende tulemus üles ehitatud valesti arusaadud IC kinemaatikale. V peatükis anname LHCb andmete korrektse tõlgenduse ja rajame teoreetilise aluse tulevastele eksperimentaalsetele otsingutele.

When people hear about the Large Hadron Collider (LHC) at CERN, they are used to think about the Higgs boson, Dark Matter and other “mysteries”. However, those of us involved in scientific research related to collider physics know that one of the main topics at the LHC is to look for the structure of the proton. Just imagine that almost 100% of our mass is not the mass of the atoms we are built of but the mass of a small part of them, namely the nucleus built up by protons and neutrons. Current experiments are focused mainly on the part of the proton structure which caries a small part of the proton momentum or on the dynamics of such parts. However, some experimental data provide evidences for the possible importance of physics at high momentum fractions, dealt with in the so called intrinsic charm (IC) model. Unfortunately, the interpretation of such data is not clear and quite speculative. One of the final states for physics at high momentum fractions is the J/ψ meson, constitued by a charm–anticharm quark pair. The J/ψ meson was discovered in 1971, but its production properties are still very questionable. Using IC, in chapter III we are trying to find a correct interpretation for the experimental data obtained by NA3 (CERN). We also prepare theoretical foundations for a correct interpretation of the current researches at the COMPASS experiment (CERN) and the future experiment AFTER@LHC. The SELEX (FermiLab) measurements of the production of doubly charmed baryons are among the most intriguing and surprising results in modern baryonic physics. Even the most recent LHCb (CERN) results are not helpful to resolve that mystery. In chapter IV, we resolved the SELEX data puzzle with IC. Probably, to this moment the reader is already suspecting that data interpretation is rather important. Recently, the LHCb collaboration tried to search for evidence for the IC in their data. Unfortunately, their result is based on the misunderstanding of the IC kinematic properties. In chapter V, we give an interpretation of the LHCb data and provide a theoretical foundation for a future experimental search.