Implementation of the Hough Transform for 3D Track Reconstruction in Drift Chambers

The paper is devoted to the method for 3D reconstruction of the straight tracks in the tracking system consisting of the drift-chamber stereo layers. The method is based on the Hough-transform approach - the discrete case of more general Radon transform - and takes into account both coordinates of the hit wires and drift distances not only for the measurements in one projection, but also in the rotated stereo layers. The proposed method allows one to resolve the right-left ambiguity and provides the accordance between vertical and horizontal projections of the track.Comment: 6 pages, 4 figures, submitted to the VIth International School-Seminar "Actual Problems of High Energy Physics", August 7-16, 2001, Gomel, Belarus, see http://gomelschool.hep.b

Emotion Regulation Difficulties in Patients With Depression

Emotsioonide regulatsioon on üldiselt seotud oma emotsioonide mingi aspekti kohandamisega vastavalt olukorrale või soovile. Varasemalt on leitud, et raskused emotsioonide regulatsioonis on seotud psühhopatoloogia esinemisega, sealhulgas meeleoluhäiretega. Käesolevas töös on uuritud emotsiooniregulatsioonis esinevaid erinevusi depressiooniga patsientidel ja tervetel kontrollisikutel. Lisaks on uuritud, kas erinevusi esineb kliinilise valimi siseselt, täpsemalt neil depressiooniga patsientidel, kellel on kaasnev ärevus- või isiksusehäire. Uuringu läbiviimisel kasutati Emotsioonide Regulatsiooni Raskuste Skaalat (DERS). Kliinilise ja kontrollgrupi vahel ilmnesid statistiliselt olulised erinevused kõigil DERS alaskaaladel, välja arvatud emotsioonide mitteteadvustamise alaskaalal. Kliinilise valimi alagruppides statistiliselt olulisi erinevusi emotsioonide regulatsioonis ei esinenud. Erinevused puudusid ka depressiooni sügavuse, melanhoolia ja komorbiidsuse olemasolu põhjal moodustatud gruppide vahel. Käesolev töö annab panuse emotsioonide regulatsiooni raskuste rolli mõistmisesse psüühikahäirete kontekstis

Neutrino Induced Coherent Pion Production off Nuclei and PCAC

We review the Rein--Sehgal model and criticize its use for low energy neutrino induced coherent pion production. We have studied the validity of the main approximations implicit in that model, trying to compare with physical observables when that is possible and with microscopical calculations. Next, we have tried to elaborate a new improved model by removing the more problematic approximations, while keeping the model still reasonably simple. Last, we have discussed the limitations intrinsic to any approach based on the partial conservation of the axial current hypothesis. In particular, we have shown the inability of such models to determine the angular distribution of the outgoing pion with respect to the direction of the incoming neutrino, except for the $q^2= 0$ kinematical point.Comment: 19 latex pages, 7 figures, 1 table. Version accepted for publication in Physical Review

Neutral current coherent pion production

We investigate the neutrino induced coherent pion production reaction at low and intermediate energies. The model includes pion, nucleon and Delta(1232) resonance as the relevant hadronic degrees of freedom. Nuclear medium effects on the production mechanisms and pion distortion are taken into account. We obtain that the dominance of the Delta excitation holds due to large cancellations among the background contributions. We consider two sets of vector and axial-vector N-Delta transition form-factors, evidencing the strong sensitivity of the results to the axial coupling C5A(0). The differences between neutrino and antineutrino cross sections, emerging from interference terms, are also discussed.Comment: 4 pages, 3 figures, minor corrections, a few references adde

Theoretical study of neutrino-induced coherent pion production off nuclei at T2K and MiniBooNE energies

We have developed a model for neutrino-induced coherent pion production off nuclei in the energy regime of interest for present and forthcoming neutrino oscillation experiments. It is based on a microscopic model for pion production off the nucleon that, besides the dominant Delta pole contribution, takes into account the effect of background terms required by chiral symmetry. Moreover, the model uses a reduced nucleon-to-Delta resonance axial coupling, which leads to coherent pion production cross sections around a factor two smaller than most of the previous theoretical estimates. In the coherent production, the main nuclear effects, namely medium corrections on the Delta propagator and the final pion distortion, are included. We have improved on previous similar models by taking into account the nucleon motion and employing a more sophisticated optical potential. As found in previous calculations the modification of the Delta self-energy inside the nuclear medium strongly reduces the cross section, while the final pion distortion mainly shifts the peak position to lower pion energies. The angular distribution profiles are not much affected by nuclear effects. Nucleon motion increases the cross section by 15% at neutrino energies of 650 MeV, while Coulomb effects on charged pions are estimated to be small. Finally, we discuss at length the deficiencies of the Rein-Sehgal pion coherent production model for neutrino energies below 2 GeV, and in particular for the MiniBooNE and T2K experiments. We also predict flux averaged cross sections for these two latter experiments and K2K.Comment: 19 latex pages, 10 figures, 2 tables. Minor changes. Version accepted for publication in Physical Review

Components of the concept «pedagogical scenario»

This paper presents an analysis of the concept of "pedagogical scenario". Various aspects of the concept are presented. The result is a list of the main components of the concept in terms of its application in electronic courses.В работе представлен анализ понятия «педагогический сценарий». Рассмотрены разные аспекты этого понятия. В результате представлен список основных компонент понятия с точки зрения применения его в электронных курсах

Nuclear Effects in Neutrino Induced Coherent Pion Production at K2K and MiniBooNE Neutrino Energies

The coherent pion production induced by neutrinos in nuclei is studied using a delta hole model in local density approximation taking into account the renormalization of $\Delta$ properties in a nuclear medium. The pion absorption effects have been included in an eikonal approximation. These effects give a large reduction in the total cross section. The numerical results for the total cross section are found to be consistent with recent experimental results from K2K and MiniBooNE collaborations and other older experiments in the intermediate energy region.Comment: 4pages, 5figure