47 research outputs found
Dezorijetirani kiralni kondenzat i fluktuacije nabijenih i neutralnih Äestica u sudarima teÅ”kih iona
The possibility of large charge and isospin fluctuations of the disoriented chiral condensate type (DCC-type) in high-energy heavy-ion collisions is studied within the framework of an unitary eikonal model. The factorization property of the scattering amplitude in the impact-parameter space of the leading two-nucleon system is used to study semiclassical production of pions in the central region. A classical source function of a pion field in the impact-parameter space was related to the semiclassical solutions of the equation of motion of the nonlinear s-model coupled to quark degrees of freedom. A multi-pion exchange potential between two quarks is derived. It is shown that in the limit of soft chiral pion bremsstrahlung, the anomalously large fluctuations in the ratio of neutral to charged pions are obtained without involving DCC formation. We also show that the DCC-type fluctuations should be suppressed if a large number of pions was produced via r-type clusters.ProuÄavali smo moguÄnost velikih fluktuacija naboja i izospina tipa DCC (DCC = dezorijentirani kiralni kondenzat) u visokoenergijskim sudarima teÅ”kih iona u okviru unitarnog eikonalnog modela. Primijenili smo svojstvo faktorizacije amplitude rasprÅ”enja u prostoru parametra sudara vodeÄih Äestica za prouÄavanje poluklasiÄne tvorbe piona u centralnom podruÄju. Funkcija klasiÄnog izvora pionskog polja u prostoru parametra sudara može se povezati s poluklasiÄnim rjeÅ”enjima jednadžbe gibanja u nelinearnom sigma-modelu vezanom na kvarkovske stupnjeve slobode. U radu se izvodi izraz za potencijal viÅ”epionske izmjene izmeÄu dva kvarka. Pokazuje se da se u limesu koÄnog zraÄenja mekanih kiralnih piona takoÄer pojavljuju anomalno velike fluktuacije omjera neutralnih i nabijenih piona neovisno o pojavi DCC-a. TakoÄer se pokazuje da bi fluktuacije tipa DCC trebale biti potisnute u sluÄaju kada se pioni proizvode uglavnom putem raspada Ļ-mezona
Dezorijetirani kiralni kondenzat i fluktuacije nabijenih i neutralnih Äestica u sudarima teÅ”kih iona
The possibility of large charge and isospin fluctuations of the disoriented chiral condensate type (DCC-type) in high-energy heavy-ion collisions is studied within the framework of an unitary eikonal model. The factorization property of the scattering amplitude in the impact-parameter space of the leading two-nucleon system is used to study semiclassical production of pions in the central region. A classical source function of a pion field in the impact-parameter space was related to the semiclassical solutions of the equation of motion of the nonlinear s-model coupled to quark degrees of freedom. A multi-pion exchange potential between two quarks is derived. It is shown that in the limit of soft chiral pion bremsstrahlung, the anomalously large fluctuations in the ratio of neutral to charged pions are obtained without involving DCC formation. We also show that the DCC-type fluctuations should be suppressed if a large number of pions was produced via r-type clusters.ProuÄavali smo moguÄnost velikih fluktuacija naboja i izospina tipa DCC (DCC = dezorijentirani kiralni kondenzat) u visokoenergijskim sudarima teÅ”kih iona u okviru unitarnog eikonalnog modela. Primijenili smo svojstvo faktorizacije amplitude rasprÅ”enja u prostoru parametra sudara vodeÄih Äestica za prouÄavanje poluklasiÄne tvorbe piona u centralnom podruÄju. Funkcija klasiÄnog izvora pionskog polja u prostoru parametra sudara može se povezati s poluklasiÄnim rjeÅ”enjima jednadžbe gibanja u nelinearnom sigma-modelu vezanom na kvarkovske stupnjeve slobode. U radu se izvodi izraz za potencijal viÅ”epionske izmjene izmeÄu dva kvarka. Pokazuje se da se u limesu koÄnog zraÄenja mekanih kiralnih piona takoÄer pojavljuju anomalno velike fluktuacije omjera neutralnih i nabijenih piona neovisno o pojavi DCC-a. TakoÄer se pokazuje da bi fluktuacije tipa DCC trebale biti potisnute u sluÄaju kada se pioni proizvode uglavnom putem raspada Ļ-mezona
Pionānukleon vezanje ovisno o intenzitetu u procesima viÅ”eÄestiÄne produkcije
We propose an intensityādependent pionānucleon coupling Hamiltonian within a unitary multiparticleāproduction model of the Auerbach-Avin-Blankenbecler-Sugar (AABS) type in which the pion field is represented by the thermalādensity matrix. Using this Hamiltonian, we explain the appearance of the negativeābinomial (NB) distribution for pions and the wellāknown empirical relation, the soācalled WrĀ“oblewski relation, in which the dispersion D of the pionāmultiplicity distribution is linearly related to the average multiplicity : D = A +B, with the coefficient A : D = A + B, s koeficijentom A < 1. Hamiltonijan naÅ”ega modela izražava se linearno pomoÄu generatora SU(1,1) grupe. TakoÄer nalazimo funkciju izvodnicu pionskog polja, koja postaje funkcija izvodnica NB raspodjele u limesu T ā 0
Svojstva stjeŔnjavanja q-deformiranog Jaynes-Cummingovog modela
We study the squeezing properties of the Jaynes-Cummings model with the q-intensity-dependent coupling interacting with initially q-deformed coherent radiation. We observe strong squeezing for small positive and small negative q values. If q ā 1 or > 1, squeezing is very weak.ProuÄavana su svojstva stjeÅ”njavanja Jaynes-Cummingovog modela s vezanjem ovisnim o intenzitetu i parametru q, u meÄudjelovanju s poÄetnom q-deformiranom koherentom radijacijom. Opaženo je jako stjeÅ”njavanje za male pozitivne i male negativne vrijednosti q. Ako je q ā 1 ili > 1, stjeÅ”njavanje je vrlo slabo
Multiplicitetne raspodjele i korelacije u prisutnosti q-deformiranih koherentnih stanja
We study the effects of q-deformed coherent states on second-order correlations and
multiplicity distributions.ProuÄavamo efekte q deformiranih koherentnih stanja na korelacije drugog reda i multiplicitetne raspodjele
Multiplicitetne raspodjele i korelacije u prisutnosti q-deformiranih koherentnih stanja
We study the effects of q-deformed coherent states on second-order correlations and
multiplicity distributions.ProuÄavamo efekte q deformiranih koherentnih stanja na korelacije drugog reda i multiplicitetne raspodjele
Pionska polja kao gaussove sluÄajne varijable i KobaāNielsenāOlesenovo skaliranje
We discuss pion distributions resulting from a Gaussian random nucleon source. Connection with a chaotic-coherent mixture, the negative-binomial distribution, and the Koba-Nielsen-Olesen scaling is derived.Diskutirane su pionske raspodjele sluÄajnog Gaussovog nukleonskog izvora. Dobivena je veza s kaos-koherentnom mjeÅ”avinom, Koba-Nielsen-Olesen skaliranjem te s negativnom binomnom raspodjelom