Production of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mi>Δ</mml:mi><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mi>Δ</mml:mi><mml:mrow><mml:mo>+</mml:mo><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math>resonances in collisions of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">He</mml:mi><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:mmultiscripts></mml:math>nuclei with carbon nuclei at 4.2 GeV/<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>c</mml:mi></mml:mrow></mml:math>per nucleon
Abstract
In conditions of $4\ensuremath{\pi}$-geometry, the production of ${\ensuremath{\Delta}}^{0}$ and ${\ensuremath{\Delta}}^{++}$ resonances in collisions of $^{4}\mathrm{He}$ nuclei with carbon nuclei at 4.2 GeV/$c$ per nucleon was investigated for the first time. The masses and widths of resonances were obtained based on an analysis of the experimental and background invariant mass distributions of $p{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$ pairs. The contributions to the pion production from decays of $\ensuremath{\Delta}$ resonances, as well as from direct pion creation, and the relative number of nucleons excited to ${\ensuremath{\Delta}}^{0}$ at freeze-out were estimated. The results obtained were compared to the corresponding data for C+C collisions at the same initial momentum 4.2 GeV/$c$ per nucleon.