Chapter 16: Decay Widths of Siegert States, Complex Scaling and Dilatation Transformation

We investigate the three-body Coulomb breakup reaction of two-neutron halo nuclei 11 Li , where we adopt the extended three-body model of 11 Li with paying attention to the pairing correlation of the nuclei, and also employ the complex scaling method (CSM) to solve the three-body unbound states of 11 Li . From the results, we cannot find any dipole resonances, at least, having small decay widths. This means that the breakup strength is exhausted by the continuum states. We compare the obtained strength showing the low energy enhancement to the several experimental data.

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Two Photon Decay Widths of Charmonium Resonances Formed in Proton Antiproton Annihilations

10.2172/1421503 ◽

1999 ◽

Author(s):

Michelle Dawn Stancari

Keyword(s):

Proton Antiproton ◽

Two Photon ◽

Photon Decay ◽

Decay Widths

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Lowering the scale of Pati-Salam breaking through seesaw mixing

Journal of High Energy Physics ◽

10.1007/jhep05(2021)199 ◽

2021 ◽

Vol 2021 (5) ◽

Author(s):

Matthew J. Dolan ◽

Tomasz P. Dutka ◽

Raymond R. Volkas

Keyword(s):

Degrees Of Freedom ◽

Tree Level ◽

Charged Current ◽

Meson Decay ◽

Neutrino Masses ◽

Down Quark ◽

The Standard Model ◽

Decay Widths ◽

Left And Right ◽

Charged Leptons

Abstract We analyse the experimental limits on the breaking scale of Pati-Salam extensions of the Standard Model. These arise from the experimental limits on rare-meson decay processes mediated at tree-level by the vector leptoquark in the model. This leptoquark ordinarily couples to both left- and right-handed SM fermions and therefore the meson decays do not experience a helicity suppression. We find that the current limits vary from $$ \mathcal{O} $$ O (80–2500) TeV depending on the choice of matrix structure appearing in the relevant three-generational charged-current interactions. We extensively analyse scenarios where additional fermionic degrees of freedom are introduced, transforming as complete Pati-Salam multiplets. These can lower the scales of Pati-Salam breaking through mass-mixing within the charged-lepton and down-quark sectors, leading to a helicity suppression of the meson decay widths which constrain Pati-Salam breaking. We find four multiplets with varying degrees of viability for this purpose: an SU(2)L/R bidoublet, a pair of SU(4) decuplets and either an SU(2)L or SU(2)R triplet all of which contain heavy exotic versions of the SM charged leptons. We find that the Pati-Salam limits can be as low as $$ \mathcal{O} $$ O (5–150) TeV with the addition of these four multiplets. We also identify an interesting possible connection between the smallness of the neutrino masses and a helicity suppression of the Pati-Salam limits for three of the four multiplets.

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