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SUMMARY:calculate Λ → pℓ¯νℓ semileptonic decay in lattice QCD
DTSTART;VALUE=DATE-TIME:20261010T071000Z
DTEND;VALUE=DATE-TIME:20261010T072500Z
DTSTAMP;VALUE=DATE-TIME:20261005T083326Z
UID:indico-contribution-2818@indico.itp.ac.cn
DESCRIPTION:Speakers: 鉴 郭 (中国科学院近代物理研究所)\nThis
  work presents a non-perturbative lattice-QCD study of the semileptonic de
 cay \\(\\Lambda \\to p\\ell\\bar{\\nu}_{\\ell}\\)\, where \\(\\ell=e\,\\mu
 \\). The main objective is to calculate the hadronic transition matrix ele
 ment\n\n$$\n\\langle p|\\bar{u}\\gamma^\\mu(1-\\gamma_5)s|\\Lambda\\rangle
 \n$$\n\nand extract the corresponding vector and axial-vector form factors
 .\n\nTwo-point and three-point correlation functions are constructed on th
 e lattice. Excited-state contamination is reduced using the summation meth
 od\, correlated global fits\, and jackknife resampling. The momentum-trans
 fer dependence of the form factors is described using a model-independent 
 \\(z\\)-expansion with the appropriate kinematic constraints.\n\nThe extra
 cted form factors are then used to calculate the differential and total de
 cay rates\,\n\n$$\n\\Gamma_\\ell\n=\n\\int_{m_\\ell^2}^{(m_\\Lambda-m_N)^2
 }\ndq^2\\\,\n\\frac{d\\Gamma_\\ell}{dq^2}\,\n$$\n\nand to determine the CK
 M matrix element \\(\\lvert V_{us}\\rvert\\). Using experimental baryon ma
 sses\, the resulting muon-to-electron decay-rate ratio is\n\n$$\nR_{\\mu/e
 }=0.16464(18)\,\n$$\n\nwhile the extracted values of \\(\\lvert V_{us}\\rv
 ert\\) are\n\n$$\nV_{us\,e}=0.2438(21)\,\nV_{us\,\\mu}=0.2557(161).\n$$\n\
 nThe study demonstrates the feasibility of determining \\(\\Lambda\\)-bary
 on semileptonic form factors from lattice QCD. Further calculations with m
 ultiple lattice spacings\, improved mass tuning\, and continuum extrapolat
 ion are required for a precision determination of \\(\\lvert V_{us}\\rvert
 \\).\n\\langle p|\\bar{u}\\gamma^\\mu(1-\\gamma_5)s|\\Lambda\\rangle\n\\]\
 n\nhttps://indico.itp.ac.cn/event/437/contributions/2818/
LOCATION:会议楼2 CXII102
URL:https://indico.itp.ac.cn/event/437/contributions/2818/
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