Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userObservation of $Xi(1620)^0$ and evidence for $Xi(1690)^0$ in $Xi_c^+ rightarrow Xi^-pi^+pi^+$ decays
139
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We report the first observation of the doubly-strange baryon $Xi(1620)^0$ in its decay to $Xi^-pi^+$ via $Xi_c^+ rightarrow Xi^- pi^+ pi^+$ decays based on a $980,{rm fb}^{-1}$ data sample collected with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. The mass and width are measured to be 1610.4 $pm$ 6.0 (stat) $^{+5.9}_{-3.5}$ (syst)~MeV$/c^2$ and 59.9 $pm$ 4.8 (stat) $^{+2.8}_{-3.0}$ (syst)~MeV, respectively. We obtain 4.0$sigma$ evidence of the $Xi(1690)^0$ with the same data sample. These results shed light on the structure of hyperon resonances with strangeness $S=-2$.
rate research
Read More
Using $(448.1pm2.9)times 10^{6}$ $psi(3686)$ events collected with the BESIII detector and a single-baryon tagging technique, we present the first observation of the decays $psi(3686)toXi(1530)^{0}bar{Xi}(1530)^{0}$ and $Xi(1530)^{0}bar{Xi}^0$. The branching fractions are measured to be ${cal{B}}(psi(3686)toXi(1530)^{0}bar{Xi}(1530)^{0}) = (6.77pm0.14pm0.39)times10^{-5}$ and ${cal{B}}(psi(3686)toXi(1530)^{0}bar{Xi}^{0}) = (0.53pm0.04pm0.03)times10^{-5}$. Here, the first and second uncertainties are statistical and systematic, respectively. In addition, the parameter associated with the angular distribution for the decay $psi(3686)toXi(1530)^{0}bar{Xi}(1530)^0$ is determined to be $alpha = 0.32pm0.19pm0.07$, in agreement with theoretical predictions within one standard deviation.
Using a data sample of 980~fb$^{-1}$ collected with the Belle detector operating at the KEKB asymmetric-energy $e^+e^-$ collider, we present evidence for the $Omega(2012)^-$ in the resonant substructure of $Omega_{c}^{0} to pi^+ (bar{K}Xi)^{-}$ ($(bar{K}Xi)^{-}$ = $K^-Xi^0$ + $bar{K}^0 Xi^-$) decays. The significance of the $Omega(2012)^-$ signal is 4.2$sigma$ after considering the systematic uncertainties. The ratio of the branching fraction of $Omega_{c}^{0} to pi^{+} Omega(2012)^- to pi^+ (bar{K}Xi)^{-}$ relative to that of $Omega_{c}^{0} to pi^{+} Omega^-$ is calculated to be 0.220 $pm$ 0.059(stat.) $pm$ 0.035(syst.). The individual ratios of the branching fractions of the two isospin modes are also determined, and found to be ${cal B}(Omega_{c}^0 to pi^+ Omega(2012)^-) times {cal B}(Omega(2012)^- to K^-Xi^0)/{cal B}(Omega_{c}^0 to pi^+ K^- Xi^0)$ = (9.6 $pm$ 3.2(stat.) $pm$ 1.8(syst.))% and ${cal B}(Omega_{c}^0 to pi^+ Omega(2012)^-) times {cal B}(Omega(2012)^- to bar{K}^0 Xi^-)/{cal B}(Omega_{c}^0 to pi^+ bar{K}^0 Xi^-)$ = (5.5 $pm$ 2.8(stat.) $pm$ 0.7(syst.))%.
Using $(10.087pm0.044)times10^{9}$ $J/psi$ events collected by the BESIII detector at the BEPCII collider, we search for the hyperon semileptonic decay $Xi^{-} rightarrow Xi^{0} e^{-} bar{ u}_{e}$. No significant signal is observed and the upper limit on the branching fraction $mathcal B(Xi^{-} rightarrow Xi^{0} e^{-} bar{ u}_{e})$ is set to be $2.59times10^{-4}$ at 90 % confidence level. This result is one order of magnitude more strict than the previous best limit.
A search for the $it{Xi}^{++}_{cc}$ baryon through the $it{Xi}^{++}_{cc} rightarrow D^{+} p K^{-} pi^{+}$ decay is performed with a data sample corresponding to an integrated luminosity of 1.7 $mathrm{fb}^{-1}$ recorded by the LHCb experiment in $pp$ collisions at a centre-of-mass energy of 13 TeV. No significant signal is observed in the mass range from the kinematic threshold of the decay to 3800 $mathrm{MeV}/c^{2}$. An upper limit is set on the ratio of branching fractions $mathcal{R} = frac{mathcal{B}(it{Xi}^{++}_{cc} rightarrow D^{+} p K^{-} pi^{+})}{mathcal{B}(it{Xi}^{++}_{cc} rightarrow Lambda^{+}_{c} K^{-} pi^{+}pi^{+})}$ with $mathcal{R} < 1.7 hspace{2pt} (2.1) times 10^{-2}$ at the 90% (95%) confidence level at the known mass of the $it{Xi}^{++}_{cc}$ state.
We show that the $Xi (1690)$ resonance can be dynamically generated in the $s$-wave $bar{K} Sigma$-$bar{K} Lambda$-$pi Xi$-$eta Xi$ coupled-channels chiral unitary approach. In our model, the $Xi (1690)$ resonance appears near the $bar{K} Sigma$ threshold as a $bar{K} Sigma$ molecular state and the experimental data are reproduced well. We discuss properties of the dynamically generated $Xi (1690)$.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
