arXiv subjects

M. V. Rzjanin

Publications and source records attributed to M. V. Rzjanin.

4 recordsLinked to original sources

arXiv2001

Open charm enhancement by secondary interactions in relativistic nucleus-nucleus collisions?

We calculate open charm production in $Pb+Pb$ reactions at SPS energies within the HSD transport approach - which is based on string, quark, diquark ($q, \bar{q}, qq, \bar{q}\bar{q}$) and hadronic degrees of freedom - including the production of open charm pairs from secondary 'meson'-'baryon' (or quark-diquark and antiquark-diquark) collisions. It is argued that at collision energies close to the $c\bar{c}$ pair threshold the dominant production mechanism is related to the two body (or quasi two body) reactions $πN \to \bar{D} (\bar{D^*}) Λ_c, (Σ_c)$. Estimates within the framework of the Quark-Gluon String model suggest cross sections of a few $μb$ for $πN \to \bar{D} Λ_c$ in the region of 1 GeV above threshold. The dynamical transport calculations for $Pb + Pb$ at 160 A$\cdot$GeV indicate that the open charm enhancement reported by the NA50 Collaboration might be due to such secondary reaction mechanisms.

hep-ph↗

arXiv1999

$ωN$ final state interactions and $ω$-meson production from heavy-ion collisions

We calculate the elastic and inelastic $ωN\to ωN, \to πN, \to ρN, \to ρπN, \to ππN, \to σN$ reactions within a boson exchange approximation where the $ωρπ$ coupling constant and form factor are fixed by the reaction $πN \to ωN$ in comparison to the experimental data. We find rather large $ωN$ cross sections at low relative momenta of the $ω$-meson which leads to a substantial broadening of the $ω$-meson width in nuclear matter. The implications of the $ωN$ final state interactions are studied for $ω$ production in $^{12}C{+}^{12}C, ^{40}Ca{+}^{40}Ca$ and $^{58}Ni{+}^{58}Ni$ reactions at about 2 A GeV within the HSD transport approach; the drastic changes of the transverse mass spectra relative to a general m_T-scaling (for $π^0$ and $η$ mesons) might be controlled experimentally by the TAPS Collaboration.

nucl-th↗

arXiv1997

Reanalysis of antiproton production in proton-nucleus and nucleus-nucleus reactions at subthreshold energies

We reanalyse the production of $p\bar{p}$ pairs in proton-nucleus and nucleus-nucleus collisions employing novel elementary cross sections for baryon-baryon and pion-baryon production channels based on a boson-exchange model. In contrast to previous transport studies performed in the literature the secondary pion induced channel is found to be most important in both p+A and A+A collisions at subthreshold energies. A detailed comparison with the experimental data available indicates that sizeable attractive $\bar{p}$ potentials in the order of - 100 to - 150 MeV at normal nuclear matter density are needed to reproduce the size and shape of the experimental spectra.

nucl-th↗

arXiv1996

Antiproton production in $pp, dp$ and $dd$ collisions close to threshold

The production of antiprotons in $pp$ collisions is investigated close to threshold where experimental data about the total cross section are not available. We analyze the latter reaction within the LUND string model for inclusive $\bar{p}$ production and within the framework of a one-boson exchange model for the exclusive reaction $pp \rightarrow ppp\bar{p}$. The application of our new results to the analysis of subthreshold antiproton production in $d + p$ and $d + d$ collisions shows cross sections that are much lower than expected before. Nevertheless, the comparison of experimental $\bar{p}$ differential cross sections from $d +p$ and $d + d$ is expected to provide valuable information about a nonnucleonic component in the deuteron wavefunction.

nucl-th↗