On two-body decays of a scalar glueball
On two-body decays of a scalar glueball
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DOI：
10.1140/epjc/s10052-008-0606-6
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发表时间：
2005-12
期刊：
影响因子：
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通讯作者：
K. Chao;Xiao-Gang He;Xiao-Gang He;Jian-Ping Ma;Jian-Ping Ma
中科院分区：
文献类型：
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作者：
K. Chao;Xiao-Gang He;Xiao-Gang He;Jian-Ping Ma;Jian-Ping Ma
我们研究标量胶球的二体衰变。我们证明，在 QCD 中，如果手性对称性完全成立，即衰减幅度受到手性抑制，则自旋 0 的纯胶球（仅具有胶子的状态）不能衰变成一对轻夸克。然而，这种手性抑制并没有在强子水平上实现，例如衰变成 π+π- 和 K+K-。我们使用低能定理和微扰 QCD 在胶球比 QCD 尺度轻得多和重得多的两种情况下明确地证明了这一点。对于重胶球，使用基于有效拉格朗日量的 QCD 分解，我们发现强子化为 ππ 和 KK 会导致 Br(π+π-) 和 Br(K+K-) 之间存在较大差异；甚至衰减幅度也没有被手性抑制。如果 Br(ππ) 或 Br(KK̄) 能够可靠测量，我们的结果可以提供对部分子含量的一些理解。
We study two-body decays of a scalar glueball. We show that in QCD a spin-0 pure glueball (a state with only gluons) cannot decay into a pair of light quarks if chiral symmetry holds exactly, i.e., the decay amplitude is chirally suppressed. However, this chiral suppression does not materialize itself at the hadron level such as in decays into π+π-and K+K-. We show this explicitly in the two cases with the glueball much lighter and much heavier than the QCD scale using low-energy theorems and perturbative QCD. For a heavy glueball, using QCD factorization based on an effective Lagrangian, we find that the hadronization into ππ and KK leads to a large difference between Br(π+π-) and Br(K+K-); even the decay amplitude is not chirally suppressed. Our results can provide some understanding of the partonic contents if Br(ππ) or Br(KK̄) is measured reliably.