Doubly-heavy baryon weak decays: Ξbc0→pK− and Ξcc+→Σc++(2520)K−

Li, Run-Hui  (School of Physical Science and Technology, Inner Mongolia University, Hohhot, 010021, China) ; Lü, Cai-Dian (Institute of High Energy Physics, YuQuanLu 19B, Beijing, 100049, China) (School of Physics, University of Chinese Academy of Sciences, YuQuanLu 19A, Beijing, 100049, China) ; Wang, Wei (INPAC, Shanghai Key Laboratory for Particle Physics and Cosmology, Department of Physics and Astronomy, Shanghai Jiao-Tong University, Shanghai, 200240, China) ; Yu, Fu-Sheng (School of Nuclear Science and Technology, Lanzhou University, Lanzhou, 730000, China) (Research Center for Hadron and CSR Physics, Lanzhou University, Institute of Modern Physics of CAS, Lanzhou, 730000, China) ; Zou, Zhi-Tian (Department of Physics, Yantai University, Yantai, 264055, China)

07 February 2017

Abstract: Doubly-heavy baryons, with two heavy and one light quarks, are expected to exist in QCD and their masses have been predicted in the quark model. However their existence is not well established so far in experiment. In this work, we explore the possibility of searching for Ξbc and Ξcc+ in the W -exchange processes, Ξbc0→pK− and Ξcc+→Σc++(2520)K− . On the basis of perturbative calculations, we estimate the branching ratio of the first decay as BR(Ξbc0→p+K−)≈3.21×Rf2×Rτ×10−7 , where Rf ( Rτ ) are the ratios of the decay constants (lifetimes) of Ξbc0 and Λb0 . The branching ratio of Ξcc+→Σc++(2520)K− is related to that of Λc+→Δ++K− , and thereby a conjectured topology analysis leads to the range for the branching ratio as: BR(Ξcc+→Σc++(2520)K−)∈[0.36%,1.80%] . The decay Ξcc+→Σc++(2520)K− would be reconstructed in the Λc+K−π+ final state which is easy to access even at a hadron collider. Based on the two facts that abundant heavy quarks can be produced at a hadron collider like LHC, and the branching ratios of Ξbc0→pK− and Ξcc+→Σc++(2520)K− are sizable, we urge our experimental colleagues to perform a search at LHCb. This will presumably lead to the discovery of the Ξbc and Ξcc+ , and precision measurements of the branching ratios in the future are helpful to investigate their decay mechanism.

Published in: Physics letters B (2017)
Published by: Elsevier
DOI: 10.1016/j.physletb.2017.02.003
License: CC-BY-3.0

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