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2019:groups:higgs:lightscalars [2019/06/26 15:32] thomas.flacke |
2019:groups:higgs:lightscalars [2019/06/27 13:44] shilpi.jain |
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- | Promising DECAYS: $\phi\to\gamma\gamma$ (and $\mu\mu$, $bb$, $\tau\tau$, Missing E_T ?) | + | Promising DECAYS: $\phi\to\gamma\gamma$ (and $\mu\mu$, $bb$, $\tau\tau$, Missing E_T ?) [names: **TF**] |
General comment: If the particle is lighter than hadronic threshold ($m_a <3m_\pi<450\rm MeV$ for CP-odd scalar), the particle is easily long-lived in the reasonable parameter space. Many literature ignores loop-factor $16\pi^2$, which sometimes leads to less physical parameter space. A scale $\Lambda/C_{\gamma\gamma}=1\rm TeV$ in [[https://arxiv.org/abs/1708.00443|1708.00443]] parameterization corresponds to a scale $f_a =6\rm GeV$ in the decay constant (SSB scale).So ALP being invisible is quite possible with sub-GeV mass and $f_a >100\rm GeV$. Estimates with ALP as missing energy in [[https://arxiv.org/abs/1409.4792|1409.4792]] (mono-jet), [[https://arxiv.org/abs/1701.05379|1701.05379]] (mono-W, mono-Z, mono-Higgs) and [[https://arxiv.org/abs/1901.03061|1901.03061]]. | General comment: If the particle is lighter than hadronic threshold ($m_a <3m_\pi<450\rm MeV$ for CP-odd scalar), the particle is easily long-lived in the reasonable parameter space. Many literature ignores loop-factor $16\pi^2$, which sometimes leads to less physical parameter space. A scale $\Lambda/C_{\gamma\gamma}=1\rm TeV$ in [[https://arxiv.org/abs/1708.00443|1708.00443]] parameterization corresponds to a scale $f_a =6\rm GeV$ in the decay constant (SSB scale).So ALP being invisible is quite possible with sub-GeV mass and $f_a >100\rm GeV$. Estimates with ALP as missing energy in [[https://arxiv.org/abs/1409.4792|1409.4792]] (mono-jet), [[https://arxiv.org/abs/1701.05379|1701.05379]] (mono-W, mono-Z, mono-Higgs) and [[https://arxiv.org/abs/1901.03061|1901.03061]]. | ||
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* Processes + models: | * Processes + models: | ||
- | * h-->Zphi--->llgamma gamma (or mu+mu-, or tau+tau- with recast from h->aa->2mu2tau, CMS-PAS-HIG-15-011) | + | * h-->Zphi--->llgamma gamma (or mu+mu-, or tau+tau- with recast from h->aa->2mu2tau, CMS-PAS-HIG-15-011) [**BB, SJ, SB**] |
* Z*-->Zphi-->llgamma or gammaphi-->3gamma | * Z*-->Zphi-->llgamma or gammaphi-->3gamma | ||
* (Above 2 with 'Bauer et al.' model) | * (Above 2 with 'Bauer et al.' model) | ||
- | * h*-->Zphi-->llgamma gamma (derive UFO rom h*-->ZZ* with add'l functionality?) | + | * h*-->Zphi-->llgamma gamma (derive UFO from h*-->ZZ* with add'l functionality?) [**SJ**] |
* qqbar/e+e--->Z*/gamma*-->Zphi-->llgamma gamma (started LH 2017) | * qqbar/e+e--->Z*/gamma*-->Zphi-->llgamma gamma (started LH 2017) | ||
* qqbar-->Z*/gamma*-->phi + 2j (VBF version of above) | * qqbar-->Z*/gamma*-->phi + 2j (VBF version of above) | ||
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* Experimental: | * Experimental: | ||
- | * 'fat' photons | + | * 'fat' photons [**SJ**] |
- | *statistical tool to produce proto-limits after proto-selections | + | *statistical tool to produce proto-limits after proto-selections [**SJ**]: Such a tool is now ready. This uses likelihood ratio as a test statistic i.e. L(s+b)/L(b). Uses Cls method to quote the upper limits which is commonly and widely used by CMS and ATLAS. This has been cross-checked against the CMS limit tool for cut and counting experiment. But the present code can be extended to do a shape based limit. |
Contributions on the above projects to the Friday closing talk (by the Higgs convenors) should include (~1-2 slides): | Contributions on the above projects to the Friday closing talk (by the Higgs convenors) should include (~1-2 slides): | ||
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Please send to Gregory, Susan and Jose by Thursday morning (so we can give a synthesis to the speaker by ~Thursday noon and also circulate among us) | Please send to Gregory, Susan and Jose by Thursday morning (so we can give a synthesis to the speaker by ~Thursday noon and also circulate among us) | ||
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