Observation of ${\Xi }_c(2930{)}^0$ and updated measurement of $B^{-}\to K^{-}{\Lambda }_c^{+}{\bar{\Lambda }}_c^{-}$ at Belle

Abstract

We report the first observation of the ${\Xi }_c(2930{)}^0$ charmed-strange baryon with a significance greater than 5$\sigma$. The ${\Xi }_c(2930{)}^0$ is found in its decay to $K^{-}{\Lambda }_c^{+}$ in $B^{-}\to K^{-}{\Lambda }_c^{+}{\bar{\Lambda }}_c^{-}$ decays. The measured mass and width are $[2928.9\pm 3.0(stat.{)}_{-12.0}^{+0.9}(syst.)]$ MeV/$c^2$ and $[19.5\pm 8.4(stat.{)}_{-7.9}^{+5.9}(syst.)]$ MeV, respectively, and the product branching fraction is $\mathcal{B}(B^{-}\to {\Xi }_c(2930{)}^0{\bar{\Lambda }}_c^{-})\mathcal{B}({\Xi }_c(2930{)}^0\to K^{-}{\Lambda }_c^{+})=[1.73\pm 0.45(stat.)\pm 0.21(syst.)]\times 10^{-4}$. We also measure $\mathcal{B}(B^{-}\to K^{-}{\Lambda }_c^{+}{\bar{\Lambda }}_c^{-})=[4.80\pm 0.43(stat.)\pm 0.60(syst.)]\times 10^{-4}$ with improved precision, and search for the charmonium-like state $Y(4660)$ and its spin partner, $Y_{\eta }$, in the ${\Lambda }_c^{+}{\bar{\Lambda }}_c^{-}$ invariant mass spectrum. No clear signals of the $Y(4660)$ nor its spin partner are observed and the 90\% credibility level (C.L.) upper limits on their production rates are determined. These measurements are obtained from a sample of $(772\pm 11)\times 10^{6}B\bar{B}$ pairs collected at the ${\rm Y}(4S)$ resonance by the Belle detector at the KEKB asymmetric energy electron-positron collider.

arXiv comment7 pages, 5 figures; accepted for publication in European Physical Journal C

References in corpus (17)

• High-Energy-Physics Event Generation with PYTHIA 6.1
• Observation of Two Resonant Structures in e+e- to pi+ pi- psi(2S) via Initial State Radiation at Belle
• Observation of a near-threshold enhancement in the e+e- -->Lambda_c+Lambda_c- cross section using initial-state radiation
• Progress Toward Understanding Baryon Resonances
• Measurement of $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\psi (2S)$ via Initial State Radiation at Belle
• Strong and radiative decays of the low-lying $S$- and $P$-wave singly heavy baryons
• Charmed Baryonium
• Evidence that the Y(4660) is a f_0(980)psi' bound state
• Decay properties of $P$-wave charmed baryons from light-cone QCD sum rules
• Low-lying charmed and charmed-strange baryon states
• Implications of heavy quark spin symmetry on heavy meson hadronic molecules
• Quantum Numbers of ${\Omega }_c$ States and Other Charmed Baryons
• A study of Bbar -> Xi_c Lambda_c^- and Bbar -> Lambda_c^+ Lambda_c^- Kbar decays at BABAR
• Charm-strange baryon strong decays in a chiral quark model
• Reconciling the X(4630) with the Y(4660)
• Study of $P$-wave excitations of observed charmed strange baryons
• An alternative fit to Belle mass spectra for DD, D*D* and Lambda_C Lambda_c

Cited by in corpus (24)

• The $XYZ$ states: experimental and theoretical status and perspectives
• An updated review of the new hadron states
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of 2018
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of 2021
• Charmed Baryon Physics Circa 2021
• Observation of new ${\Xi }_c^0$ baryons decaying to ${\Lambda }_c^{+}{K}^{-}$
• Charmed baryon spectrum from lattice QCD near the physical point
• Assigning the newly reported ${\Sigma }_b(6097)$ as a $P$-wave excited state and predicting its partners
• $P$-wave charmed baryons of the $SU(3)$ flavor $6_F$
• Heavy Flavour Physics and CP Violation at LHCb: a Ten-Year Review
• Strong decay widths and mass spectra of charmed baryons
• Identification of newly observed singly charmed baryons using relativistic flux tube model
• Understanding the newly observed ${\Xi }_c^0$ states through their decays
• Evidence of a new excited charmed baryon decaying to ${\Sigma }_c(2455{)}^{0,++}{\pi }^{\pm }$
• Identifying the ${\Xi }_c^0$ baryons observed by LHCb as $P$-wave ${\Xi }_c^{\prime }$ baryons
• Investigating the spectroscopy behavior of undetected $1F$-wave charmed baryons
• Open charm hadron spectroscopy at B-factories
• On the nature of ${\Xi }_c(2930)$
• 70 Years of Hyperon Spectroscopy: A review of strange $\Xi$, $\Omega$ baryons, and the spectrum of charmed and bottom baryons
• Molecular pentaquark states with open charm and bottom flavors
• Study of the $B^{-}\to {\Lambda }_c^{+}{\bar{\Lambda }}_c^{-}{K}^{-}$ decay
• Heavy-quark dominance and fine structure of excited heavy baryons ${\Sigma }_Q$, ${\Xi }_Q^{\prime }$ and ${\Omega }_Q$
• Observation of a new charmed baryon decaying to ${\Xi }_c^{+}{\pi }^{-}{\pi }^{+}$
• Mass spectra of singly heavy baryons in the relativized quark model with heavy-quark dominance