No Arabic abstract
The inclusive reaction $p A to pK^0_s + X$ was studied at IHEP accelerator with $70 GeV/c$ proton beam using SVD-2 detector. Two different samples of $K^0_s$, statistically independent and belonging to different phase space regions, were used in the analyses and a narrow baryon resonance with the mass $M=1523pm 2(stat.)pm 3(syst.) MeV/c^2$ was observed in both samples of the data. The combined statistical significance was estimated to be of 8.0 (392 signal over 1990 background events). Using the part of events reconstructed with better accuracy the width of resonance was constrained to $Gamma < 14 MeV/c^2$ at 95% C.L. The $x_F$ distribution was found to have a peak at zero with {$<|x_F|> approx 0.1$}, that qualitatively agrees to a Regge-based model predictions. A new cross section estimate of $sigma cdot BR(Theta^+ to pK^0) = 4.9 pm 1.0(stat.) pm 1.5(syst.) mu b/nucleon$ for $x_F > 0$ was obtained.
SVD-2 experiment data have been analyzed to search for an exotic baryon state, the $Theta^+$-baryon, in a $pK^0_s$ decay mode at $70 GeV/c$ on IHEP accelerator. The reaction $pA to pK^0_s+X$ with a limited multiplicity was used in the analysis. The $pK^0_s$ invariant mass spectrum shows a resonant structure with $M=1526pm3(stat.)pm 3(syst.) MeV/c^2$ and $Gamma < 24 MeV/c^2$. The statistical significance of this peak was estimated to be of $5.6 sigma$. The mass and width of the resonance is compatible with the recently reported $Theta^+$- baryon with positive strangeness which was predicted as an exotic pentaquark ($uuddbar{s}$) baryon state. The total cross section for $Theta^+$ production in pN-interactions for $X_Fge 0$ was estimated to be $(30div120) mu b$ and no essential deviation from A-dependence for inelastic events $(sim A^{0.7})$ was found.
We report on the SVD-2 experiment data analysis aimed to search for an exotic baryon state, the $Theta^+$-baryon, in a $pK^0_s$ decay mode with IHEP U-70 accelerator proton beam at $70 GeV/c$. A resonant structure with $M=1526pm3(stat.)pm 3(syst.)~MeV/c^2$ and $Gamma < 24 MeV/c^2$ was found in the $pK^0_s$ invariant mass spectrum, with the statistical significance of this peak estimated as $5.6~sigma$.
The inclusive reaction $p A to pK^0_s + X$ was studied at IHEP accelerator with $70 GeV$ proton beam using SVD-2 detector. Two different samples of $K^0_s$, statistically independent and belonging to different phase space regions were used in the analyses and a narrow baryon resonance with the mass $M=1523pm 2(stat.)pm 3(syst.) MeV/c^2$ was observed in both samples of the data. The statistical significance was estimated to be of $8.0 sigma$ (392 signal over 1990 background events). Using the part of events reconstructed with better accuracy the width of resonance was estimated to be $Gamma < 14 MeV/c^2$ at 95% C.L.
The inclusive reaction $p A to pK^0_s + X$ was studied at IHEP accelerator with $70 GeV$ proton beam using SVD-2 detector. Two different samples of $K^0_s$, statistically independent and belonging to different phase space regions were used in the analyses and a narrow baryon resonance with the mass $M=1523pm 2(stat.)pm 3(syst.) MeV/c^2$ was observed in both samples of the data
The results of data handling for E-184 experiment obtained with 70 GeV proton beam irradiation of active target with carbon, silicon and lead plates are presented. Two-prongs neutral charmed D0 and v{D}0 -mesons decays were selected. Signal / background ratio was (51+/-17) / (38+/-13). Registration efficiency for mesons was defined and evaluation for charm production cross section at threshold energy is presented: sigma(c^c) = 7.1 +/- 2.4(stat.) +/- 1.4(syst.) (mu/nucleon).