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

Resolution of puzzles from the LSND, KARMEN, and MiniBooNE experiments

This work has attempted to reconcile puzzling neutrino oscillation results from the LSND, KARMEN and MiniBooNE experiments. We show that the LSND evidence for $\bar{\nu}_\mu \to \bar{\nu}_e$ oscillations, its long-standing disagreement with the results from KARMEN, and the anomalous event excess observed by MiniBooNE in $\nu_\mu$ and $\bar{\nu}_\mu$ data could all be explained by the existence of a heavy sterile neutrino ($\nu_h$). All these results are found to be consistent with each other assuming that the $\nu_h$ is created in $\nu_\mu$ neutral-current interactions and decays radiatively into a photon and a light neutrino. Assuming the $\nu_h$ is produced through mixing with $\nu_\mu$, the combined analysis of the LSND and MiniBooNe excess events suggests that the $\nu_h$ mass is in the range from 40 to 80 MeV, the mixing strength is $|U_{\mu h}|^2 \simeq 10^{-3}-10^{-2}$, and the lifetime is $\tau_{\nu_h} \lesssim 10^{-9}$ s. Surprisingly, this LSND-MiniBooNE parameters window is found to be unconstrained by the results from the most sensitive experiments searching for heavy neutrino. We set new limits on $|U_{\mu h}|^2$ for the LSND-MiniBooNE favorable mass region from the precision measurements of the Michel spectrum by the TWIST experiment. The results obtained provide a strong motivation for a sensitive search for the $\nu_h$ in a near future $K$ decay or neutrino experiments, which fit well in the existing/planned experimental programs at CERN or FNAL. The question of whether the heavy neutrino is Dirac or Majorana particle is briefly discussed.Comment: 24 pages, 28 figures, version to appear in PR

Angular Steering for Proportional Navigation-commanded Surface-to-air Guided Missile

The paper briefly reviews the guidance laws and their implementation in surface-to-airmissiles. The trajectories for the line-of-sight and proportional navigation guidance laws arediscussed and the effect of steering on demand for increased lateral acceleration is appreciated.The mathematical model is then evolved to estimate the launch angle of the missile, ie, bearingand elevation, in the direction of the future position of the moving air target as well as thesteering commands in pitch and yaw planes in accordance with the proportional navigationguidance law, to enable collision with the target