Observation of the Electromagnetic Radiative Decays of the Λ(1520) and Λ(1690) to γΣ0

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Observation of the Electromagnetic Radiative Decays of the Λ(1520) and Λ(1690) to γΣ0. / The BESIII Collaboration ; Ачасов, Михаил Николаевич ; Мучной, Николай Юрьевич и др.

в: Physical Review Letters, Том 136, № 14, 141801, 08.04.2026.

Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование

BibTeX

@article{b64a202cb49c40848957a42a7dd78083,

title = "Observation of the Electromagnetic Radiative Decays of the Λ(1520) and Λ(1690) to γΣ0",

abstract = "Using {\dh}10087 44{\TH} × 106 J=ψ events collected with the BESIII detector, we present a study of resonant structures in the J=ψ → ΛΛ¯ γ and ΛΣ¯ 0γ processes, reporting the first observation of the electromagnetic radiative decays of the Λ{\dh}1520{\TH} and Λ{\dh}1690{\TH} to γΣ0, with a statistical significance of 16.6σ and 23.2σ, respectively. The ratio of the branching fractions fB½Λ{\dh}1520{\TH} → γΛ=B½Λ{\dh}1520{\TH} →γΣ0g is determined to be 3.19 0.34{\dh}stat{\TH} 0.19{\dh}syst{\TH}, which is in agreement with flavor SU(3) symmetry within two standard deviations. The branching fraction of Λ{\dh}1520{\TH} → γΣ0 is measured to be B½Λ{\dh}1520{\TH} → γΣ0¼½2.66 0.28{\dh}stat{\TH} 0.50{\dh}syst{\TH} × 10−3, corresponding to a partial width of Γ½Λ{\dh}1520{\TH} → γΣ0¼½46.8 6.6{\dh}stat{\TH} 9.3{\dh}syst{\TH} keV, which is inconsistent with predictions fromthe relativized constituent quark model and the Algebraic model. Additionally, we observe a clear resonant structure in the γΣ0 mass spectrum near 1.7 GeV=c2, attributed to the Λ{\dh}1690{\TH}. The product branching fraction B½J=ψ → ΛΛ¯ {\dh}1690{\TH}{\th} c:c: × B½Λ{\dh}1690{\TH} → γΣ0 is measured for the first time as ½6.05 0.42{\dh}stat{\TH} 0.39{\dh}syst{\TH} × 10−6. However, no corresponding structure is seen in the γΛ mass spectrum, so an upper limit on the product branching fraction B½J=ψ → ΛΛ¯ {\dh}1690{\TH}{\th} c:c: × B½Λ{\dh}1690{\TH} → γΛ is determined to be 5.08 × 10−7 at the 90% confidence level.",

keywords = "Particle decays, Hyperons, Exotic baryons, Flavor symmetries",

author = "{BESIII Collaboration} and Ачасов, {Михаил Николаевич} and Мучной, {Николай Юрьевич} and Николаев, {Иван Борисович}",

note = "The BESIII Collaboration thanks the staff of BEPCII and the IHEP computing center for their strong support. This work is supported in part by National Key R&D Program of China under Contracts No. 2025YFA1613900, No. 2023YFA1606000, and No. 2023YFA1606704; the National Natural Science Foundation of China (NSFC) under Contracts No. 11635010, No. 11935015, No. 11935016, No. 11935018, No. 12025502, No. 12035009, No. 12035013, No. 12061131003, No. 12192260, No. 12192261, No. 12192262, No. 12192263, No. 12192264, No. 12192265, No. 12221005, No. 12225509, No. 12235017, No. 12342502, No. 12361141819, and No. 12475089; the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program; CAS under Contract No. YSBR-101; 100 Talents Program of CAS; The Institute of Nuclear and Particle Physics (INPAC) and Shanghai Key Laboratory for Particle Physics and Cosmology; German Research Foundation DFG under Contract No. FOR5327; Istituto Nazionale di Fisica Nucleare, Italy; Knut and Alice Wallenberg Foundation under Contracts No. 2021.0174 and No. 2021.0299; Ministry of Development of Turkey under Contract No. DPT2006K-120470; National Research Foundation of Korea under Contract No. NRF-2022R1A2C1092335; National Science and Technology fund of Mongolia; Polish National Science Centre under Contract No. 2024/53/B/ST2/00975; Swedish Research Council under Contract No. 2019.04595; and U.S. Department of Energy under Contract No. DE-FG02-05ER41374.",

year = "2026",

month = apr,

day = "8",

doi = "10.1103/l6g2-2wg6",

language = "English",

volume = "136",

journal = "Physical Review Letters",

issn = "0031-9007",

publisher = "American Physical Society",

number = "14",

}

RIS

TY - JOUR

T1 - Observation of the Electromagnetic Radiative Decays of the Λ(1520) and Λ(1690) to γΣ0

AU - BESIII Collaboration

AU - Ачасов, Михаил Николаевич

AU - Мучной, Николай Юрьевич

AU - Николаев, Иван Борисович

N1 - The BESIII Collaboration thanks the staff of BEPCII and the IHEP computing center for their strong support. This work is supported in part by National Key R&D Program of China under Contracts No. 2025YFA1613900, No. 2023YFA1606000, and No. 2023YFA1606704; the National Natural Science Foundation of China (NSFC) under Contracts No. 11635010, No. 11935015, No. 11935016, No. 11935018, No. 12025502, No. 12035009, No. 12035013, No. 12061131003, No. 12192260, No. 12192261, No. 12192262, No. 12192263, No. 12192264, No. 12192265, No. 12221005, No. 12225509, No. 12235017, No. 12342502, No. 12361141819, and No. 12475089; the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program; CAS under Contract No. YSBR-101; 100 Talents Program of CAS; The Institute of Nuclear and Particle Physics (INPAC) and Shanghai Key Laboratory for Particle Physics and Cosmology; German Research Foundation DFG under Contract No. FOR5327; Istituto Nazionale di Fisica Nucleare, Italy; Knut and Alice Wallenberg Foundation under Contracts No. 2021.0174 and No. 2021.0299; Ministry of Development of Turkey under Contract No. DPT2006K-120470; National Research Foundation of Korea under Contract No. NRF-2022R1A2C1092335; National Science and Technology fund of Mongolia; Polish National Science Centre under Contract No. 2024/53/B/ST2/00975; Swedish Research Council under Contract No. 2019.04595; and U.S. Department of Energy under Contract No. DE-FG02-05ER41374.

PY - 2026/4/8

Y1 - 2026/4/8

N2 - Using ð10087 44Þ × 106 J=ψ events collected with the BESIII detector, we present a study of resonant structures in the J=ψ → ΛΛ¯ γ and ΛΣ¯ 0γ processes, reporting the first observation of the electromagnetic radiative decays of the Λð1520Þ and Λð1690Þ to γΣ0, with a statistical significance of 16.6σ and 23.2σ, respectively. The ratio of the branching fractions fB½Λð1520Þ → γΛ=B½Λð1520Þ →γΣ0g is determined to be 3.19 0.34ðstatÞ 0.19ðsystÞ, which is in agreement with flavor SU(3) symmetry within two standard deviations. The branching fraction of Λð1520Þ → γΣ0 is measured to be B½Λð1520Þ → γΣ0¼½2.66 0.28ðstatÞ 0.50ðsystÞ × 10−3, corresponding to a partial width of Γ½Λð1520Þ → γΣ0¼½46.8 6.6ðstatÞ 9.3ðsystÞ keV, which is inconsistent with predictions fromthe relativized constituent quark model and the Algebraic model. Additionally, we observe a clear resonant structure in the γΣ0 mass spectrum near 1.7 GeV=c2, attributed to the Λð1690Þ. The product branching fraction B½J=ψ → ΛΛ¯ ð1690Þþ c:c: × B½Λð1690Þ → γΣ0 is measured for the first time as ½6.05 0.42ðstatÞ 0.39ðsystÞ × 10−6. However, no corresponding structure is seen in the γΛ mass spectrum, so an upper limit on the product branching fraction B½J=ψ → ΛΛ¯ ð1690Þþ c:c: × B½Λð1690Þ → γΛ is determined to be 5.08 × 10−7 at the 90% confidence level.

AB - Using ð10087 44Þ × 106 J=ψ events collected with the BESIII detector, we present a study of resonant structures in the J=ψ → ΛΛ¯ γ and ΛΣ¯ 0γ processes, reporting the first observation of the electromagnetic radiative decays of the Λð1520Þ and Λð1690Þ to γΣ0, with a statistical significance of 16.6σ and 23.2σ, respectively. The ratio of the branching fractions fB½Λð1520Þ → γΛ=B½Λð1520Þ →γΣ0g is determined to be 3.19 0.34ðstatÞ 0.19ðsystÞ, which is in agreement with flavor SU(3) symmetry within two standard deviations. The branching fraction of Λð1520Þ → γΣ0 is measured to be B½Λð1520Þ → γΣ0¼½2.66 0.28ðstatÞ 0.50ðsystÞ × 10−3, corresponding to a partial width of Γ½Λð1520Þ → γΣ0¼½46.8 6.6ðstatÞ 9.3ðsystÞ keV, which is inconsistent with predictions fromthe relativized constituent quark model and the Algebraic model. Additionally, we observe a clear resonant structure in the γΣ0 mass spectrum near 1.7 GeV=c2, attributed to the Λð1690Þ. The product branching fraction B½J=ψ → ΛΛ¯ ð1690Þþ c:c: × B½Λð1690Þ → γΣ0 is measured for the first time as ½6.05 0.42ðstatÞ 0.39ðsystÞ × 10−6. However, no corresponding structure is seen in the γΛ mass spectrum, so an upper limit on the product branching fraction B½J=ψ → ΛΛ¯ ð1690Þþ c:c: × B½Λð1690Þ → γΛ is determined to be 5.08 × 10−7 at the 90% confidence level.

KW - Particle decays

KW - Hyperons

KW - Exotic baryons

KW - Flavor symmetries

UR - https://www.scopus.com/pages/publications/105036590751

U2 - 10.1103/l6g2-2wg6

DO - 10.1103/l6g2-2wg6

M3 - Article

C2 - 42033694

VL - 136

JO - Physical Review Letters

JF - Physical Review Letters

SN - 0031-9007

IS - 14

M1 - 141801

ER -

ID: 83714573