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2019:groups:higgs:seminvisible [2019/06/21 10:33] jose.miguel.no |
2019:groups:higgs:seminvisible [2019/06/24 01:06] (current) tevong.you |
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Responsible: Jose Miguel No | Responsible: Jose Miguel No | ||
- | Participants: ... | + | Participants/[the dream team]: Sophie W, Benj, Jérémie Quevillon, José Zurita, ... |
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**Visible decays:** Search for axion-like particles (ALPs) via h -> Z a (a -> gamma gamma). Preliminary study from Bauer, Neubert, Thamm [[https://arxiv.org/abs/1708.00443|1708.00443]]. They put limits on very light ALPs (m_a < 47 MeV) from constraints on h -> Z gamma, since for m_a < 47 MeV the two photons from the ALP decay are very collimated and seen as one in the detector. For not-so-light ALPs, they compute just number of signal events. | **Visible decays:** Search for axion-like particles (ALPs) via h -> Z a (a -> gamma gamma). Preliminary study from Bauer, Neubert, Thamm [[https://arxiv.org/abs/1708.00443|1708.00443]]. They put limits on very light ALPs (m_a < 47 MeV) from constraints on h -> Z gamma, since for m_a < 47 MeV the two photons from the ALP decay are very collimated and seen as one in the detector. For not-so-light ALPs, they compute just number of signal events. | ||
- | Goal would be to provide a better estimate of LHC sensitivity to h -> Z a, a -> gamma gamma resolved (including some sort of background study?). | + | Goal could be to provide a better estimate of LHC sensitivity to h -> Z a, a -> gamma gamma resolved (including some sort of background study?). |
**Semi-visible decays:** | **Semi-visible decays:** | ||
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h-> gamma + E_T^miss__ | h-> gamma + E_T^miss__ | ||
+ | Initial pheno study by Riccardo et al [[https://arxiv.org/abs/1203.4563|1203.4563]], but seems not to work for current LHC triggers? (check!). Check coverage by ATLAS/CMS searches for gamma + E_T^miss + X. | ||
__h-> Z + E_T^miss__ | __h-> Z + E_T^miss__ | ||
+ | Can be e.g. motivated by h -> Z a (with a -> DM DM, pseudo-scalar portal to DM), by h -> Z Z' (again, with a dark Z'), by h -> chi1 chi2 (with fermion/scalar chi1 invisible). Challenging since if the Higgs is not produced in association with another object, this is just Z + small E_T^miss (~ 20 GeV). SM Higgs decay h -> Z Z* -> Z vv constitutes possible sensitivity floor, corresponding to a BR(h->Z+E_T^miss) = 0.4 %. | ||
+ | Possible to probe the decay via p p -> Z h -> 4l + E_T^miss? Quite small rate ~ 4 fb times BR(h->Z+E_T^miss). SM background ZZ -> 4l cross section is ~ 35 fb, so maybe possible. Alternative option to probe same physics in mono-Higgs: p p -> Z* -> h + E_T^miss. | ||
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