Endpoint Relations for Baryons

Abstract

Following our earlier work we establish kinematic endpoint relations for baryon decays using the Wigner-Eckart theorem and apply them to $\frac{1}{2}\to \frac{1}{2}$ and $\frac{1}{2}\to \frac{3}{2}$ baryon transitions. We provide angular distributions at the kinematic endpoint which hold for the generic $d=6$ model-independent effective Hamiltonian. Moreover, we explicitly verify the endpoint relations using an explicit form factor parametrisation and clarify constraints on helicity based form factors to evidence endpoint relations. Our results provide guidance for phenomenological parameterisations, consistency checks for theory computations and experiment. Results are applicable to ongoing and future new physics searches at LHCb, BES III and Belle II with rare semileptonic-, dineutrino-and charged-modes, which include ${\Lambda }_b\to {\Lambda }^{(\ast )}\ell \ell ,{\Lambda }_b\to {\Lambda }^{(\ast )}\nu \nu$, ${\Omega }_b\to \Omega \ell \ell$, ${\Lambda }_c\to p\ell \ell$, $\Sigma \to p\ell \ell$ and ${\Lambda }_b\to {\Lambda }_c^{(\ast )}\ell \nu$

21pp + refs, derived tensor form factor constraints and discussion of vicinity of endpoint

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Cited by in corpus (11)

• ${\Lambda }_c\to {\Lambda }^{\ast }(1520)$ form factors from lattice QCD and improved analysis of the ${\Lambda }_b\to {\Lambda }^{\ast }(1520)$ and ${\Lambda }_b\to {\Lambda }_c^{\ast }(2595,2625)$ form factors
• ${\Lambda }_b\to p$ transition form factors in perturbative QCD
• Dispersive bounds for local form factors in ${\Lambda }_b\to \Lambda$ transitions
• ${\Lambda }_b\to {\Lambda }_c$ Form Factors from QCD Light-Cone Sum Rules
• Charm-baryon semileptonic decays and the strange ${\Lambda }^{\ast }$ resonances: New insights from lattice QCD
• Transition form factors and angular distributions of the ${\mathbf{\Lambda }}_{\mathbf{b}}\to \mathbf{\Lambda }(1520)(\to \mathbf{N}\bar{\mathbf{K}}){\mathbf{\ell }}^{+}{\mathbf{\ell }}^{-}$ decay supported by baryon spectroscopy
• Rare radiative decays of charm baryons
• Light-Cone Sum Rules Analysis of ${\Xi }_{Q{Q}^{\prime }q}\to {\Sigma }_{Q^{\prime }}^{\ast }$ Weak Decays
• $D_s^{\ast }\to \varphi$ helicity form factors and the exclusive weak decays
• Angular distribution of ${\Lambda }_b^0\to p{K}^{-}{\ell }^{+}{\ell }^{-}$ decays comprising $\Lambda$ resonances with spin up to $\le 5/2$
• Null test searches for BSM physics with rare charm decays