TY - JOUR
T1 - Charm-baryon semileptonic decays and the strange Λ∗ resonances
T2 - New insights from lattice QCD
AU - Meinel, Stefan
AU - Rendon, Gumaro
N1 - Funding Information: We thank M. Bordone, S. Descotes-Genon, G. Hiller, C. Marin-Benito, J. Toelstede, D. van Dyk, and R. Zwicky for discussions. We are grateful to the RBC and UKQCD Collaborations for making their gauge field ensembles available. S. M. is supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award No. DE-SC0009913. G. R. is supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract No. DE-SC0012704 (BNL). The computations for this work were carried out on facilities at the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH1123, and on facilities of the Extreme Science and Engineering Discovery Environment (XSEDE) , which is supported by National Science Foundation Grant No. ACI-1548562. We acknowledge the use of chroma , qp hi x , qlua , mdwf , and related usqcd software . Publisher Copyright: © 2022 authors. Published by the American Physical Society.
PY - 2022/3/1
Y1 - 2022/3/1
N2 - Understanding the properties of the strange Λ∗ baryon resonances is a long-standing and fascinating problem. Λc charm-baryon semileptonic weak decays to these resonances are highly sensitive to their internal structure and can be used to test theoretical models. We have performed the first lattice-QCD computation of the form factors governing Λc semileptonic decays to a Λ∗ resonance: the Λ∗(1520), which has negative parity and spin 3/2. Here we present the resulting Standard Model predictions of the Λc→Λ∗(1520)+ν differential and integrated decay rates as well as angular observables. Furthermore, by combining the recent BESIII measurement of the Λc→Xe+νe inclusive semipositronic branching fraction [Phys. Rev. Lett. 121, 251801 (2018)PRLTAO0031-900710.1103/PhysRevLett.121.251801] with lattice-QCD predictions of the Λc→Λe+νe, Λc→ne+νe, and Λc→Λ∗(1520)e+νe decay rates, we obtain an upper limit on the sum of the branching fractions to all other semipositronic final states. In particular, this upper limit constrains the Λc→Λ∗(1405)e+νe branching fraction to be very small, which may be another hint for a molecular structure of the Λ∗(1405).
AB - Understanding the properties of the strange Λ∗ baryon resonances is a long-standing and fascinating problem. Λc charm-baryon semileptonic weak decays to these resonances are highly sensitive to their internal structure and can be used to test theoretical models. We have performed the first lattice-QCD computation of the form factors governing Λc semileptonic decays to a Λ∗ resonance: the Λ∗(1520), which has negative parity and spin 3/2. Here we present the resulting Standard Model predictions of the Λc→Λ∗(1520)+ν differential and integrated decay rates as well as angular observables. Furthermore, by combining the recent BESIII measurement of the Λc→Xe+νe inclusive semipositronic branching fraction [Phys. Rev. Lett. 121, 251801 (2018)PRLTAO0031-900710.1103/PhysRevLett.121.251801] with lattice-QCD predictions of the Λc→Λe+νe, Λc→ne+νe, and Λc→Λ∗(1520)e+νe decay rates, we obtain an upper limit on the sum of the branching fractions to all other semipositronic final states. In particular, this upper limit constrains the Λc→Λ∗(1405)e+νe branching fraction to be very small, which may be another hint for a molecular structure of the Λ∗(1405).
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U2 - https://doi.org/10.1103/PhysRevD.105.L051505
DO - https://doi.org/10.1103/PhysRevD.105.L051505
M3 - Article
SN - 2470-0010
VL - 105
JO - Physical Review D
JF - Physical Review D
IS - 5
M1 - L051505
ER -