利用SU(3)味對稱研究魅重子衰變

Charmed baryon decays with SU(3) flavor symmetry

劉佳韋(Chia-Wei Liu)

指導教授 ： 耿朝強

國立清華大學/理學院/物理學系/博士(2020年)

摘要

我們利用 SU(3) 味對稱分析了魅重子衰變到八重態(十重態)重子及贗純量(向量)介子的衰變參數。在 SU(3) 味對稱的分析中,這是首次色對稱部分的等效哈密頓量被完整地考慮。我們得到的衰變參數跟以往文獻有些出入,其中α(Λ+c → Ξ0K+)SU(3) = 0.94+0.06−0.11 與實驗值 0.77 ± 0.78 相符,但大多的文獻的預言皆為 0。我們也探討了 Ks-KL 衰變不對稱。對於包含向量介子的衰變,我們指出 Λ+c → Λ0ρ+ ,Ξ0c → Ξ−ρ+ ,Λ+c → Λ0K∗+ , Ξ+c → Σ+φ 和 Ξ0c → Ξ−K∗+ 有著顯著的衰變分之比和較差的衰變參數,這些理論值適合在未來的實驗中被檢驗。

關鍵字

味對稱

並列摘要

We analyze the decay processes of Bc → BnM, BnV, BDM with the SU(3)F flavor symmetry and spin-dependent amplitudes, where Bc, Bn(BD) and M(V ) are the anti-triplet charmed baryon, octet(decuplet) baryon and pseudo-scalar(vector) meson states, respectively. In the SU(3)F approach, it is the first time that the decay rates and asymmetries are fully and systematically studied without neglecting the O(15) contributions of the color-symmetric parts in the effective Hamiltonian. Our results of the up-down asymmetries based on SU(3)F are quite different from the previous theoretical values in the literature. We find that (Λ+c → Ξ0K+)SU(3) = 0:94+0.06-0.11, which is consistent with the recent experimental data of 0.77 ± 0.78 by the BESIII Collaboration, but predicted to be zero in the literature. We also examine the K0S - K0L asymmetries between the decays of Bc → Bn(BD)K0S and Bc → Bn(BD)K0L with both Cabibbo-allowed and doubly Cabibbo-suppressed transitions. For decay involved vector mesons we point out that the Cabbibo allowed decays of Λ+c → Λ0ρ+ and Ξ0c → Ξ−ρ+ as well as the singly Cabbibo suppressed ones of Λ+c → Λ0K∗+ , Ξ+c → Σ+φ and Ξ0c → Ξ−K∗+ have large branching ratios and decay parameters with small uncertainties, which can be tested by the experimental searches at the charm facilities.

並列關鍵字

flavor symmetry

參考文獻

[1] R. Aaij et al. [LHCb Collaboration], Phys. Rev. D 100, 032001 (2019)

[2] M. Tanabashi et al. [Particle Data Group], Phys. Rev. D 98, 030001 (2018).

[3] S. B. Yang et al. [Belle Collaboration], Phys. Rev. Lett. 117, 011801 (2016)

[4] M. Ablikim et al. [BESIII Collaboration], Phys. Rev. Lett. 116, 052001

(2016).