A Search for Selectrons and Squarks at HERA

Data from electron-proton collisions at a center-of-mass energy of 300 GeV are used for a search for selectrons and squarks within the framework of the minimal supersymmetric model. The decays of selectrons and squarks into the lightest supersymmetric particle lead to final states with an electron and hadrons accompanied by large missing energy and transverse momentum. No signal is found and new bounds on the existence of these particles are derived. At 95% confidence level the excluded region extends to 65 GeV for selectron and squark masses, and to 40 GeV for the mass of the lightest supersymmetric particle.Comment: 13 pages, latex, 6 Figure

A Measurement of the Proton Structure Function F ⁣2(x,Q2)F_{\!2}(x,Q^2)

A measurement of the proton structure function $F_{\!2}(x,Q^2)$ is reported for momentum transfer squared $Q^2$ between 4.5 $GeV^2$ and 1600 $GeV^2$ and for Bjorken $x$ between $1.8\cdot10^{-4}$ and 0.13 using data collected by the HERA experiment H1 in 1993. It is observed that $F_{\!2}$ increases significantly with decreasing $x$, confirming our previous measurement made with one tenth of the data available in this analysis. The $Q^2$ dependence is approximately logarithmic over the full kinematic range covered. The subsample of deep inelastic events with a large pseudo-rapidity gap in the hadronic energy flow close to the proton remnant is used to measure the "diffractive" contribution to $F_{\!2}$.Comment: 32 pages, ps, appended as compressed, uuencoded fil

Исследование точности отверстий и их усадки в обрабатываемых дорнованием втулках

В работе рассмотрены область применения ,виды дорнов, схема процесса дорнования отверстия, схема параметры дорнования отверстия, плюсы и минусы дорнования, и оборудование для дорнования. Потом использование конечно-элементного программного обеспечения ANSYS для моделирования процесса обработки. Затем проведено исследование зависимости усадки отверстия от натяга, степени толстостенности, механических свойств материала, а также исследована кривизна обработанных отверстий. В заключении изложены выводы о проделанной работе и представлено уравнение описывающее исследованные зависимости.In the work, the scope of application, types of mandrels, a diagram of the mandrel process of a hole, a diagram of the parameters of a mandrel of a hole, the pros and cons of mandrel, and equipment for mandrel are considered. Then the use of ANSYS finite element software to simulate the processing process. Then the study of the dependence of the hole shrinkage on the tightness, the degree of thickness, the mechanical properties of the material was carried out, and the curvature of the machined holes was also investigated. In the conclusion, the conclusions about the work done are presented and the equation describing the investigated dependences is presented

Results from pion calibration runs for the H 1 liquid argon calorimeter and comparisons with simulations

We present results on calibration runs performed with pions at the CERN SPS for different modules of the H 1 liquid argon calorimeter which consists of an electromagnetic section with lead absorbers and a hadronic section with steel absorbers. The data cover an energy range from 3.7 to 205 GeV. Detailed comparisons of the data and simulation with GHEISHA 8 in the framework of GEANT 3.14 are presented. The measured pion induced shower profiles are well described by the simulation. The total signal of pions on an energy scale determined from electron measurements is reproduced to better than 3% in various module configurations. After application of weighting functions, determined from Monte Carlo data and needed to achieve compensation, the reconstructed measured energies agree with simulation to about 3%. The energies of hadronic showers are reconstructed with a resolution of about ⨸50%√E⨸ 2%. This result is achieved by inclusion of signals from an iron streamer tube tail catcher behind the liquid argon stacks

Total photoproduction cross-section measurement at HERA energies

We present first results on the total photoproduction cross section measurement with the H1 detector at HERA. The data were extracted from low Q2 collisions of 26.7 GeV electrons with 820 GeV protons. The γp total cross section has been measured by two independent methods in the γp center of mass energy range from 90 to 290 GeV. For an average center of mass energy of 195 GeV a value of σtot (γp) = 159 ± 7 (stat.) ± 20 (syst.) μb was obtained. © 1993.0320 auteursSCOPUS: ar.jinfo:eu-repo/semantics/publishe