Partonske raspodjele u nukleonu na osnovi relativističkog modela neovisnih kvarkova

At a low resolution scale with Q2 = µ2 corresponding to the nucleon bound state, deep inelastic unpolarized structure functions F1(x, µ2) and F2(x, µ2) are derived, with correct support using the symmetric part of the hadronic tensor under some simplifying assumptions in the Bjorken limit. For doing this, the nucleon in its ground state has been represented by a suitably constructed momentum wave packet of its valence quarks in their appropriate SU(6) spin flavour configuration, with the momentum probability amplitude taken phenomenologically in reference to the independent quark model of scalar-vector harmonic potential. The valence quark distribution functions uv(x, µ2) and dv(x, µ2), extracted from the structure function F1(x, µ2) in a parton model interpretation, satisfy normalization constraints as well as the momentum sum-rule requirements at a bound state scale of µ2 = 0.1 GeV2. QCD evolution of these distribution functions taken as the inputs, yields at Q2 0 = 15 GeV2, xuv(x, Q2 0) and xdv(x, Q2 0) in good qualitative agreement with the experimental data. The gluon distribution G(x, Q2 0) and the sea-quark distribution qs(x, Q2 0), which are dynamically generated using the leading order renormalization group equation, also match reasonably well with the available experimental data.Upotrebom simetričnog dijela hadronskog tenzora, uz pojednostavljenje u Bjorkenovoj granici, izveli smo duboko-neelastične strukturne funkcije bez polarizacije F1(x, µ2) i F2(x, µ2) za slabo razlučivanje sa Q2 = µ2, što odgovara vezanom nukleonskom stanju. Nukleon se u svom osnovnom stanju predstavlja pogodno odabranim impulsnim valnim paketom svojih valentnih kvarkova u prikladnom SU(6) spinskom okusnom sklopu, a impulsne amplitude vjerojatnosti uzimaju se fenomenološki prema modelu neovisnih kvarkova skalarno-vektorskog harmoničkog potencijala. Iz strukturne funkcije F1(x, µ2) izvode se funkcije raspodjele valentnih kvarkova uv(x, µ2) i dv(x, µ2) u partonskom modelu, i one zadovoljavaju uvjete normalizacije i impulsnog zbrojnog pravila na ljestvici vezanja µ2 = 0.1 GeV2. Polazeći od tih funkcija za Q2 0 = 15 GeV2, QCD razvoj daje xuv(x, Q2 0) i xdv(x, Q2 0), u dobrom skladu s mjernim podacima. Gluonska G(x, Q2 0) i kvarkovska qs(x, Q2 0) raspodjela tvore se dinamički upotrebom jednadžbe renormalizacijske grupe u prvom redu i također se dobro slažu s mjernim podacima

Interference of stochastic resonances: Splitting of Kramers' rate

We consider the escape of particles located in the middle well of a symmetric triple well potential driven sinusoidally by two forces such that the potential wells roll as in stochastic resonance and the height of the potential barrier oscillates symmetrically about a mean as in resonant activation. It has been shown that depending on their phase difference the application of these two synchronized signals may lead to a splitting of time averaged Kramers' escape rate and a preferential product distribution in a parallel chemical reaction in the steady state