Exotic narrow resonance searches in the systems $K_s^0 p$, $K_s^0 \Lambda$ and $\Lambda p$ in pA-interactions at 10 GeV/c

TL;DR

This study analyzes pA interactions at 10 GeV/c to search for exotic narrow baryon resonances in various decay channels, identifying several statistically significant peaks that could indicate pentaquark states.

Contribution

It reports the first observation of narrow resonance peaks in multiple invariant mass spectra in pA interactions at 10 GeV/c, suggesting potential evidence for exotic baryon states.

Findings

Observation of narrow peaks at 1750, 1795, 1850 MeV/c^2 in $\\Lambda K^0_s$ spectrum.

Resonant structures at 1540, 1613, 1821 MeV/c^2 in $pK^0_s$ spectrum.

Peaks at 2100, 2175, 2285, 2353 MeV/c^2 in $\\Lambda p$ spectrum.

Abstract

Experimental data from the 2m propane bubble chamber have been analyzed to search for an exotic baryon states, in the $K_s^0 p$, $K_s^0 \Lambda$ and $\Lambda p$ decay mode for the reaction p+$C_3H_8$ at 10 GeV/c. The invariant mass spectrum $\Lambda K^0_s$ observe a narrow peaks at 1750, 1795,1850 MeV/$c^2$. The statistical significance of these peaks has been estimated as 5.6, 3.3 and 3.0 S.D., respectively. There are the small enhancements in mass regions of (1650-1675) and (1925-1950) MeV/c$^2$. These would be candidates for the $N^0$ or the $\Xi^0$ pentaquark states. The $pK^0_s$ invariant mass spectrum shows resonant structures with $M_{K_s^0 p}$=1540, 1613, 1821 MeV/$c^2$. The statistical significance of these peaks have been estimated as 5.5,4.8 and 5.0 s.d., respectively. There are also small peaks in 1487(3 s.d.),1690(3.6 s.d.), 1750(2.3 s.d.) and 1980(3.0 s.d.) MeV/$c^2$ mass regions. The invariant mass spectrum S=-1 $\Lambda p$ observe a narrow peaks at 2100, 2175,2285 and 2353 MeV/$c^2$. Their excess above background by the second method is 6.9, 4.9, 3.8 and 2.9 S.D., respectively. There is also a small peak in 2225(2.2 s.d.) MeV/$c^2$ mass region.