Search

The transverse profile of electromagnetic showers in a calorimeter made of TΦ 1-00 lead glass was measured at electron energies of 3, 9, and 23 GeV for two configurations of the setup: with and without an assembly of passive material being placed in front of the calorimeter. The method for obtaining the shower profile did not require the use of high-precision coordinate detectors. Parameterization of shower profiles by a two-dimensional function with two parameters was proposed. A program for simulating Cherenkov light in a lead glass calorimeter was developed. The experimental data agree with the results of Monte Carlo simulation within the limits of experimental errors.

A precise measurement of the angle $\alpha$ in the CKM triangle is very important for a complete test of Standard Model. A theoretically clean method to extract $\alpha$ is provided by B$^0 \to \rho \pi$ decays. Monte Carlo simulations to obtain the BTeV reconstruction efficiency and to estimate the signal to background ratio for these decays were performed. Finally the time-dependent Dalitz plot analysis, using the isospin amplitude formalism for tree and penguin contributions, was carried out. It was shown that in one year of data taking BTeV could achieve an accuracy on $\alpha$ better than 5$^{\circ}$.

The electromagnetic calorimeter for detecting incident photons in a wide range (up to ±250 mrad) of angles was investigated using simulated electromagnetic showers with energies of 0.5–5 GeV. The peculiarities of the procedure for reconstructing the coordinates and the shape of a shower in the actual spectrometer prototype were considered. The results of simulation were compared to the test measurements.

For the kinematical region specified by the inequalities −0.4 < xF < −0.1 and 0.9 < pT < 2.5 GeV/c, the results are presented that were obtained by experimentally determining the single-spin asymmetry of inclusive neutral-pion production in the reaction p + p↑ → π0 + X at 70 GeV. According to these results, the asymmetry is close to zero in the region −0.2 < xF < −0.1 and grows in magnitude with decreasing xF, amounting to (−10.6 ± 3.2)% for −0.4

Results are presented that were obtained by measuring single-spin asymmetry in the inclusive production of neutral pions in the reaction p+p ↑→ π0+X at xF≈0. A beam of 70-GeV protons was extracted directly from the vacuum chamber of the accelerator by means of a bent single crystal. For transverse momenta in the range 1.0

Data on the single-spin asymmetry (AN) of inclusive π0 production in 40-GeV pion interactions with a polarized target, π−+↑→π0+X, are presented for the target-fragmentation region. The result is AN=(−13.8±3.8)% for −0.8