新山　雅之
   所属   京都産業大学  理学部 物理科学科
   職種   教授
発行・発表の年月 2020/07
形態種別 その他
標題 First Determination of the Spin and Parity of a Charmed-Strange Baryon, $Ξ_{c}(2970)^+$
執筆形態 その他
著者・共著者 Belle Collaboration,T. J. Moon,K. Tanida,Y. Kato,S. K. Kim,I. Adachi,J. K. Ahn,H. Aihara,S. Al Said,D. M. Asner,V. Aulchenko,T. Aushev,R. Ayad,V. Babu,S. Bahinipati,P. Behera,C. Beleño,J. Bennett,M. Bessner,B. Bhuyan,T. Bilka,J. Biswal,G. Bonvicini,A. Bozek,M. Bračko,T. E. Browder,M. Campajola,L. Cao,D. Červenkov,M. -C. Chang,P. Chang,A. Chen,B. G. Cheon,K. Chilikin,K. Cho,S. -K. Choi,Y. Choi,S. Choudhury,D. Cinabro,S. Cunliffe,N. Dash,G. De Nardo,F. Di Capua,Z. Doležal,T. V. Dong,D. Dossett,S.
概要 We report results from a study of the spin and parity of $\Xi_{c}(2970)^+$
using a $980~\mathrm{fb^{-1 } }$ data sample collected by the Belle detector at
the KEKB asymmetric-energy $e^{+}e^{-}$ collider. The decay angle distributions
in the chain $\Xi_{c}(2970)^+ \to \Xi_c(2645)^{0}\pi^{+} \to
\Xi_c^{+}\pi^{-}\pi^{+}$ are analyzed to determine the spin of this
charmed-strange baryon. The angular distributions strongly favor the
$\Xi_{c}(2970)^+$ spin $J =1/2$ over $3/2$ or $5/2$, under an assumption that
the lowest partial wave dominates in the decay. We also measure the ratio of
$\Xi_{c}(2970)^+$ decay branching fractions $R={\mathcal{B}[ \Xi_{c}(2970)^+
\to \Xi_c(2645)^{0}\pi^{+} ]} / { \mathcal{B}[ \Xi_{c}(2970)^+ \to
\Xi_c^{\prime0}\pi^{+} ]} =1.67 \pm 0.29\mathrm{(stat.)}^{ +0.15}_{
-0.09}\mathrm{(syst.)} \pm 0.25\mathrm{(IS)}$, where the last uncertainty is
due to possible isospin-symmetry-breaking effects. This $R$ value favors the
spin-parity $J^P=1/2^+$ with the spin of the light-quark degrees of freedom
$s_{l}=0$. This is the first determination of the spin and parity of a
charmed-strange baryon.
DOI 10.1103/PhysRevD.103.L111101
PermalinkURL http://arxiv.org/abs/2007.14700v1
researchmap用URL http://arxiv.org/pdf/2007.14700v1