arXiv subjects

M. Atayan

Publications and source records attributed to M. Atayan.

10 recordsLinked to original sources

arXiv2009

A study of the neutrinoproduction of Phi and D_s^+ mesons

The neutrinoproduction of $ϕ$ and $D^+_s$ mesons is studied, using the data obtained with the SKAT bubble chamber at the Serpukhov accelerator. It is found that the $ϕ$ production occurs predominantly in the forward hemisphere of the hadronic c.m.s. (at $x_F > 0$, $x_F$ being the Feynman variable), with the mean yield strongly exceeding the expected yield of directly produced $ϕ$ mesons and varying from $ 0) > = (0.92\pm0.34) \cdot 10^{-2}$ at $W > $ 2 GeV up to $(1.23\pm0.53) \cdot 10^{-2}$ at $W >$ 2.6 GeV and $(1.44\pm0.69) \cdot 10^{-2}$ at $W >$ 2.9 GeV, $W$ being the invariant mass of the hadronic system. The yield of leading $D^+_s$ mesons carrying more than $z = 0.85$ of the current $c$- quark energy is estimated: at $W > 2.9$ GeV, $ 0.85) > = (6.64\pm1.91) \cdot 10^{-2}$. It is shown, that the shape of the $ϕ$ meson differential spectrum on $x_F$ is reproduced by that expected from the $D^+_s \to ϕX$ decays which, however, can account for only the half of the measured $ϕ$ yield.

hep-ex↗

arXiv2008

The yields of light meson resonances in neutrinonuclear interactions at = 10 GeV

The total yields of the all well-established light mesonic resonances (up to the $ϕ$(1020) meson) are estimated in neutrinonuclear interactions at < E_nu > = 10 GeV, using the data obtained with SKAT bubble chamber. For some resonances, the yields in the forward and backward hemispheres in the hadronic c.m.s. are also extracted. From the comparison of the obtained and available higher-energy data, an indication is obtained that the resonance yields rise almost linearly as a function of the mean mass < W > of the neutrinoproduced hadronic system. The fractions of pions originating from the light resonance decays are inferred.

hep-ex↗

arXiv2008

Charged rho meson production in neutrino-induced reactions at E_nu = 10 GeV

The neutrinoproduction of charged $ρ$ mesons on nuclei and nucleons is investigated for the first time at moderate energies ($ \approx$ 10 GeV), using the date obtained with SKAT bubble chamber. No strong nuclear effects are observed in $ρ^+$ and $ρ^-$ production. The fractions of charged and neutral pions originating from $ρ$ decays are obtained and compared with higher energy data. From analysis of the obtained and available data on $ρ^+$ and $K^{*+}$(892) neutrinoproduction, the strangeness suppression factor in the quark string fragmentation is extracted: $λ_s = 0.18\pm0.03$. Estimations are obtained for cross sections of quasiexclusive single $ρ^+$ and coherent $ρ^+$ neutrinoproduction on nuclei. The estimated coherent cross section $σ_{ρ^+}^{coh}$ = (0.29$\pm0.16)\cdot 10^{-38}$ cm$^2$ is compatible with theoretical predictions.

hep-ex↗

arXiv2006

A study of the double hadron neutrinoproduction on nuclei

The nuclear medium influence on the dihadron neutrinoproduction is investigated for the first time, using the data obtained with SKAT bubble chamber. An indication is obtained that the nuclear attenuation of the dihadron is more expressed for kinematically closest hadron pairs. The experimental data on the dihadron attenuation and on the ratio of the dihadron to single-hadron yields are compared with predictions of the two-scale string fragmentation model.

hep-ex↗

arXiv2005

The A - dependence of rho^0 neutrinoproduction on nuclei

The A - dependence of rho^0 meson production in neutrino-induced reactions is investigated for the first time, using the data obtained with SKAT bubble chamber. The nuclear medium influence on the rho^0 total yield and inclusive distributions (on z = E_rho/nu and Feynman x_F variables) is found to be approximately the same as for pions. It is shown, that these distributions, with increasing A, tend to shift toward smaller values of z and x_F, thus indicating on an increasing role of secondary intranuclear interactions. The predictions of a simplified model incorporating the latter are found to be in qualitative agreement with experimental data.

hep-ex↗

arXiv2005

The total yields of K^+(892), Sigma^+(1385) and Sigma^0 in neutrino-induced reactions at = 10 GeV

Using the data obtained with SKAT bubble chamber, the total yields of $K^+(892)$, $Σ^+(1385)$ and $Σ^0$ are estimated for the first time in neutrino-induced reactions at moderate energies ($ $ = 10.4 GeV). It is shown, that the recently observed \cite{ref1,ref2} enhancement of the $K^0$ and $Λ$ yields in $νA$ interactions (as compared to $νN$ interactions) is contributed only slightly by the $K^+(892)$ and $Σ^+(1385)$ production, respectively. The decay contribution to the $K^0$ and $Λ$ yields is found to be in qualitative agreement with higher energy ($ \geq$ 40 GeV) data. It is shown, that the energy dependence of the $K^+(892)$ mean multiplicity in $νN$ interactions is approximately linear in the range of $ \approx$ 10-60 GeV, while that for $Σ^0$ in $νA$ interactions (for $A$ = 20-21) is approximately logarithmic in the range of $ \approx$ 10-150 GeV.

hep-ex↗

arXiv2005

The A - dependence of $K^{0}$ and $Λ$ neutrinoproduction on nuclei

For the first time, the A- dependence of the production of $K^0$, $Λ$ and, for comparison, $π^-$ mesons is investigated in neutrinonuclear reactions, using the data obtained with SKAT bubble chamber. An exponential parametrization ($\sim A^β$) of the particle yields results in $β_{V^0} = 0.20 \pm 0.05$ for $V^0$ particles (combined $K^0$ and $Λ$), while for $π^-$ mesons the A- dependence is much weaker, $β_{π^-} = 0.068 \pm 0.007$. A nuclear enhancement of the ratio $K^0/π^-$ is found; this ratio increases from $0.055 \pm 0.013$ for $νN$- interactions up to $0.070 \pm 0.011$ at $A \approx 21$ and $0.099 \pm 0.011$ at $A \approx 45$. It is observed, that the multiplicity rise of $V^0$'s occures predominantely in the backward hemisphere of the hadronic c.m.s. It is shown, that the A- dependence of the nuclear enhancement of the $Λ^0$ and $π^-$ yields can be reproduced in the framework of a model, incorporating the secondary intranuclear interactions of pions originating from the primary $νN$- interactions, while only (29$\pm$9)% of that for $K^0$ at $A \approx 45$ can be attributed to intranuclear interactions.

hep-ex↗

arXiv2005

The LUCIAE model predictions on the light vector meson production in proton-proton, proton-nucleus and nucleus-nucleus collisions at 158 A GeV

The LUCIAE model predictions are compared with experimental data on light vector meson ($ρ,ω,ϕ$) production in pp, p+Pb and Pb+Pb collisions at 158 A GeV. The model reproduces the general trends of the data, but fails in describing the yield of high-$p_T$ vector mesons in the central Pb+Pb collisions. Predictions for In+In and p+A (A varying from Be to U) collisions at 158 A GeV are also presented.

hep-ex↗

arXiv2004

The characteristics of neutrinonuclear reactions at E_nu = 1 - 3 GeV

For the first time, the characteristics of the charged current neutrinonuclear interactions are investigated at $E_ν$ = 1 - 3 GeV using the data obtained with SKAT propane-freon bubble chamber irradiated in the neutrino beam at Serpukhov accelerator. The $E_ν$ - dependence of the mean multiplicities of different types of secondary particles and their multiplicity, momentum and angular distributions are measured.

hep-ex↗

arXiv2003

A study of the nuclear medium influence on transverse momentum of hadrons produced in deep inelastic neutrino scattering

The influence of nuclear effects on the transverse momentum $(p_T)$ distributions of neutrinoproduced hadrons is investigated using the data obtained with SKAT propane-freon bubble chamber irradiated in the neutrino beam (with $E_ν$ = 3-30 GeV) at Serpukhov accelerator. Dependences of $ $ on the kinematical variables of inclusive deep-inelastic scattering and of the produced hadrons are measured. It has been observed, that the nuclear effects cause an enhancement of $ $ of hadrons (more pronounced for the positively charged ones) produced in the target fragmentation region at low invariant mass of the hadronic system (2 $< W <$ 4 GeV) or at low energies transferred to the current quark (2 $< ν< 9$ GeV). At higher $W$ or $ν$, no influence of nuclear effects on $ $ is observed. Measurement results are compared with predictions of a simple model, incorporating secondary intranuclear interactions of hadrons (with a formation length extracted from the Lund fragmentation model), which qualitatively reproduces the main features of the data.

hep-ex↗