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2019:groups:higgs:lightscalars [2019/06/27 13:43] shilpi.jain |
2019:groups:higgs:lightscalars [2019/06/27 16:39] aoife.bharucha |
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Below 80-90GeV, for a generic (pseudo-)scalar $\phi$ (light Higgs, radion, dilaton, axion, ALP's...), the decay $\phi$ → Z*Z is kinematically closed and $\phi$ → $\gamma\gamma$ becomes challenging to trigger on, so that the gluon-gluon Fusion mechanism to produce $\phi$ is not promising anymore (see for instance [[https://arxiv.org/abs/1607.08653|1607.08653]]). | Below 80-90GeV, for a generic (pseudo-)scalar $\phi$ (light Higgs, radion, dilaton, axion, ALP's...), the decay $\phi$ → Z*Z is kinematically closed and $\phi$ → $\gamma\gamma$ becomes challenging to trigger on, so that the gluon-gluon Fusion mechanism to produce $\phi$ is not promising anymore (see for instance [[https://arxiv.org/abs/1607.08653|1607.08653]]). | ||
- | * Quick contur study using the BNT ALP UFO file. All couplings set to zero except the photons which is scanned over. {{ :2019:groups:higgs:combinedhybrid.pdf | 2D scan }}. Over a wide range of $\phi$ masses ($M_{ALP}$ on the plot) the sensitivity extends down to $C_{\gamma\gamma}/\Lambda \approx 3$ TeV$^{-1}$. | + | * Quick contur study using the BNT ALP UFO file. All couplings set to zero except the photons which is scanned over. {{ :2019:groups:higgs:combinedhybrid.pdf | 2D scan }}. Over a wide range of $\phi$ masses ($M_{ALP}$ on the plot) the sensitivity extends down to $C_{\gamma\gamma}/\Lambda \approx 3$ TeV$^{-1}$. Here the scan is performed over the following ranges: $m_a:\quad 1 \to 50$ GeV, $g_{a\gamma\gamma}:\quad 10 \to 10^-6$, $g_{aZ\gamma}:\quad 10 \to 10^-6$ |
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* Checking at an example point in the above scan, $M_{ALP} = 1.8$ GeV, $C_{\gamma\gamma}/\Lambda = 5.2$ TeV$^{-1}$, all other couplings set to zero. The $\phi$ decays 100% to $\gamma\gamma$ as expected (width $10^{-7}$ GeV). The main production mechanisms are $\gamma, W$ or $Z$ + $\phi$. $gg \rightarrow \phi$ is zero. The different subprocess cross sections are visible in the example Herwig output file: {{ :2019:groups:higgs:lhc-s101-runpoint_0095.out.txt | lhc-s101-runpoint_0095.out}} | * Checking at an example point in the above scan, $M_{ALP} = 1.8$ GeV, $C_{\gamma\gamma}/\Lambda = 5.2$ TeV$^{-1}$, all other couplings set to zero. The $\phi$ decays 100% to $\gamma\gamma$ as expected (width $10^{-7}$ GeV). The main production mechanisms are $\gamma, W$ or $Z$ + $\phi$. $gg \rightarrow \phi$ is zero. The different subprocess cross sections are visible in the example Herwig output file: {{ :2019:groups:higgs:lhc-s101-runpoint_0095.out.txt | lhc-s101-runpoint_0095.out}} | ||
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{{ :2019:groups:higgs:alp-pr.tar.gz |ALP UFO file }} from [[https://arxiv.org/abs/1708.00443|Bauer, Neubert, Thamm]] with fix for the ALP mass / Higgs/ Z mass bug from Peter Richardson. | {{ :2019:groups:higgs:alp-pr.tar.gz |ALP UFO file }} from [[https://arxiv.org/abs/1708.00443|Bauer, Neubert, Thamm]] with fix for the ALP mass / Higgs/ Z mass bug from Peter Richardson. | ||
- | {{ :2019:groups:higgs:alp_chiral_ufo_v2.tar.gz |ALP UFO file }} from [[https://arxiv.org/abs/1701.05379|Brivio, Gavela, Merlo, Mimasu, No, del Rey, Sanz]] (with fix for the ALP width). | + | {{ :2019:groups:higgs:alp_chiral_ufo_v2.tar.gz |ALP UFO file }} from [[https://arxiv.org/abs/1701.05379|1701.05379]] (Brivio, Gavela, Merlo, Mimasu, No, del Rey, Sanz) (with fix for the ALP width). |
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{{ :2019:groups:higgs:alp_linear_ufo.tar.gz | ALP linear UFO file }} from [[https://arxiv.org/abs/1701.05379|Brivio, Gavela, Merlo, Mimasu, No, del Rey, Sanz]] (also with fix for the ALP width - GP). | {{ :2019:groups:higgs:alp_linear_ufo.tar.gz | ALP linear UFO file }} from [[https://arxiv.org/abs/1701.05379|Brivio, Gavela, Merlo, Mimasu, No, del Rey, Sanz]] (also with fix for the ALP width - GP). | ||
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* tprime--tphi, phi-->gamma gamma (singlet pseudo-scalar, composite Higgs) | * tprime--tphi, phi-->gamma gamma (singlet pseudo-scalar, composite Higgs) | ||
- | * Theoretical: recasting as 2HDM | + | * Theoretical: recasting as 2HDM and other benchmark models [**JQ**] |
* Experimental: | * Experimental: | ||
* 'fat' photons [**SJ**] | * 'fat' photons [**SJ**] | ||
- | *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 which can bring ~30% improvement compared to a simple cut and count. | + | *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): |