Exploring a low-mass H dibaryon in light of the LZ event: A QCD sum rule study
Abstract
The LUX-ZEPLIN (LZ) Collaboration recently reported a candidate event consistent with a high-energy nuclear recoil, motivating a possible interpretation by Lee, Takahashi, and Tsai involving the production of an invisible baryon-number-two scalar with a mass near $1.85$ GeV. Motivated by this hypothetical scenario, we investigate the JP=0+ uuddss hexaquark system using QCD sum rules. We consider five local diquark-diquark-diquark interpolating currents with different scalar and axial-vector diquark combinations, together with a baryon-baryon current constructed from two Λ-type baryon currents. The operator product expansions are calculated up to dimension sixteen, and their numerical behaviors are examined under different OPE truncations. Among the currents considered, only the SU(3)flavor-singlet current JSSS, consisting of three scalar color-3̅C diquarks, yields a low-mass solution at D=12, with MSSS=1.85+0.19−0.20 GeV. Interestingly, scalar color-3̅C diquarks belong to the flavor 3̅F representation, and their local color-singlet construction has a unique nonvanishing flavor structure, $[ud][ds][su]$, corresponding to uuddss. Analogous all-scalar-diquark currents vanish for other flavor configurations, such as uuuddd and uuudds. Together with our QCD sum-rule results, this property highlights the special role of the all-scalar-diquark configuration, $[ud][ds][su]$, as a possible deeply bound structure. However, the higher-dimensional OPE contributions exhibit significant truncation dependence, and the low-mass solution remains conditional on the adopted OPE truncation rather than constituting a fully controlled mass prediction.
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BibTeX
@misc{tan2026exploring,
title = {{Exploring a low-mass H dibaryon in light of the LZ event: A QCD sum rule study}},
author = {Wei-Han Tan and Hua-Xing Chen},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.25925},
eprint = {2610.25925},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.25925},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Exploring a low-mass H dibaryon in light of the LZ event: A QCD sum rule study
AU - Wei-Han Tan
AU - Hua-Xing Chen
PY - 2026
DA - 2026/10/22
PB - arXiv
DO - 10.48550/arxiv.2610.25925
UR - https://arxiv.org/abs/2610.25925
AB - The LUX-ZEPLIN (LZ) Collaboration recently reported a candidate event consistent with a high-energy nuclear recoil, motivating a possible interpretation by Lee, Takahashi, and Tsai involving the production of an invisible baryon-number-two scalar with a mass near $1.85$ GeV. Motivated by this hypothetical scenario, we investigate the J^P=0^+ uuddss hexaquark system using QCD sum rules. We consider five local diquark-diquark-diquark interpolating currents with different scalar and axial-vector diquark combinations, together with a baryon-baryon current constructed from two Λ-type baryon currents. The operator product expansions are calculated up to dimension sixteen, and their numerical behaviors are examined under different OPE truncations. Among the currents considered, only the SU(3)_flavor-singlet current J_SSS, consisting of three scalar color-3̅_C diquarks, yields a low-mass solution at D=12, with M_SSS=1.85^+0.19_−0.20 GeV. Interestingly, scalar color-3̅_C diquarks belong to the flavor 3̅_F representation, and their local color-singlet construction has a unique nonvanishing flavor structure, $[ud][ds][su]$, corresponding to uuddss. Analogous all-scalar-diquark currents vanish for other flavor configurations, such as uuuddd and uuudds. Together with our QCD sum-rule results, this property highlights the special role of the all-scalar-diquark configuration, $[ud][ds][su]$, as a possible deeply bound structure. However, the higher-dimensional OPE contributions exhibit significant truncation dependence, and the low-mass solution remains conditional on the adopted OPE truncation rather than constituting a fully controlled mass prediction.
ER -