First observation of the semileptonic decay <math display="inline"><mrow><msubsup><mrow><mi mathvariant="normal">Λ</mi></mrow><mrow><mi>c</mi></mrow><mrow><mo>+</mo></mrow></msubsup><mo stretchy="false">→</mo><mi>p</mi><msup><mrow><mi>K</mi></mrow><mrow><mo>-</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msub><mrow><mi>ν</mi></mrow><mrow><mi>e</mi></mrow></msub></mrow></math>

Ablikim, Medina; Achasov, Mikhail N.; Adlarson, Patrik Adlarsson; Albrecht, Malte; Aliberti, Riccardo; Amoroso, Antonio; An, Meiru; An, Qi; Bai, Xuhong; Bai, Yu

doi:10.1103/PhysRevD.106.112010

First observation of the semileptonic decay $Λ_{c}^{+} \to p K^{-} e^{+} ν_{e}$

BESIII

Collaboration

Jul 23, 2022

10 pages

Published in:

Phys.Rev.D 106 (2022) 11, 112010

Published: Dec 1, 2022

e-Print:

2207.11483 [hep-ex]

DOI:

10.1103/PhysRevD.106.112010 (publication)

PDG:

{{\mathit \Lambda}_{{{c}}}^{+}}

\rightarrow

{{\mathit p}}{{\mathit K}^{-}}{{\mathit e}^{+}}{{\mathit \nu}_{{{e}}}}

Experiments:

View in:

ADS Abstract Service

pdf

reference search18 citations

Citations per year

Abstract: (APS)

Using

4.5 {fb}^{- 1}

of

e^{+} e^{-}

annihilation data samples collected at the center-of-mass energies ranging from 4.600 GeV to 4.699 GeV with the BESIII detector at the BEPCII collider, a first study of the semileptonic decays

Λ_{c}^{+} \to p K^{-} e^{+} ν_{e}

,

Λ_{c}^{+} \to Λ (1520) e^{+} ν_{e}

and

Λ_{c}^{+} \to Λ (1405) e^{+} ν_{e}

is performed. The

Λ_{c}^{+} \to p K^{-} e^{+} ν_{e}

decay is observed with a significance of

8.2 σ

and the branching fraction is measured to be

B (Λ_{c}^{+} \to p K^{-} e^{+} ν_{e}) = (0.88 \pm 0.1 7_{stat} \pm 0.0 7_{syst}) \times 10^{- 3}

. We also report evidence of

Λ_{c}^{+} \to Λ (1520) e^{+} ν_{e}

and

Λ_{c}^{+} \to Λ (1405) e^{+} ν_{e}

with significances of

3.3 σ

and

3.2 σ

, respectively, and measure

B (Λ_{c}^{+} \to Λ (1520) e^{+} ν_{e}) = (1.02 \pm 0.5 2_{stat} \pm 0.1 1_{syst}) \times 10^{- 3}

and

B (Λ_{c}^{+} \to Λ (1405) [\to p K^{-}] e^{+} ν_{e}) = (0.42 \pm 0.1 9_{stat} \pm 0.0 4_{syst}) \times 10^{- 3}

. Combining these with the inclusive semileptonic

Λ_{c}^{+}

branching fraction measured by BESIII, the relative fraction is determined to be

[B (Λ_{c}^{+} \to p K^{-} e^{+} ν_{e}) / B (Λ_{c}^{+} \to X e^{+} ν_{e})] = (2.1 \pm 0. 4_{stat} \pm 0. 2_{syst}) %

, which provides a clear confirmation that semileptonic

Λ_{c}^{+}

decays are not saturated by the

Λ ℓ^{+} ν_{ℓ}

final state.

Note:

13 pages, 9 figures and 2 tables

electron positron: annihilation
electron positron: colliding beams
branching ratio: measured
branching ratio: ratio: measured
Lambda/c+: branching ratio
Lambda(1520)
mass spectrum: (p K-)
BES
Beijing Stor
Lambda/c+: semileptonic decay

References(51)

Figures(9)

[1]

CP Violation in the Renormalizable Theory of Weak Interaction

Makoto Kobayashi
(
- Kyoto U.
)
,
Toshihide Maskawa
(
- Kyoto U.
)

- Prog.Theor.Phys. 49 (1973) 652-657,
- Also in *Lichtenberg, D. B. (Ed.), Rosen, S. P. (Ed.): Developments In The Quark Theory Of Hadrons, Vol. 1*, 218-223.
•
DOI:
- 10.1143/PTP.49.652