Les Houches

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Responsibles: Grégory Moreau [TH](moreau@th.u-psud.fr), Jose Miguel No [TH] (josemiguel.no@uam.es), Susan Gascon-Shotkin [EXP](smgascon@mail.cern.ch)

People involved (TBC!!): Sophie Williamson (swilliamson@lpthe.jussieu.fr), Aoife Bharucha (aoife.bharucha@cpt.univ-mrs.fr), Antoine Lesauvage (antoine.baptiste.lesauvage@cern.ch), Jérémie Quevillon (jeremie.quevillon@lpsc.in2p3.fr), Shilpi Jain(shilpi.jain@cern.ch), Shankha Banerjee (banerjeeshankha@gmail.com), Biplob Bhattacherjee(bbhattacherjee@gmail.com), Nishita Desai (nishita.desai@umontpellier.fr), Jon Butterworth (J.Butterworth@ucl.ac.uk), Natascia Vignaroli (vignaroli@pd.infn.it), Kohsaku Tobioka (ktobioka@fsu.edu), José Zurita (jose.zurita@kit.edu), Giacomo Polesello (giacomo.polesello@cern.ch).

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Exotic Higgs decays into h → Z $\phi$ (see also discussion in seminvisible).

Reference to look for general motivation on exotic Higgs decays, possible models, etc, as well as for information on theoretical work and experimental analylis (as of 2013!): Review/compendium work on exotic Higgs decays from Curtin, Gori, Shelton, Strassler et al 1312.4992.

We consider two decay modes of $\phi$: $\phi \to \gamma \gamma$, $\phi \to \mu \mu$

• $\phi$ → $\gamma\gamma$. (SG)

Preliminary study from Bauer, Neubert, Thamm 1708.00443 (see also 1704.08207).

For m_a < 47 MeV, constraints from $h \to Z \gamma$, since for m_a < 47 MeV the two photons from the $\phi$ decay are very collimated and seen as one in the detector.

For m_a > 47 MeV, they compute just number of signal events for $gg \to h \to Z \phi$, and assume limits for 100 events at LHC.

$m_\phi < 35$ GeV: $h \to Z \phi$ (on-shell $Z \to \ell\ell$)

$m_\phi > 35$ GeV: $h \to Z^* \phi$ ($h \to \ell\ell \phi$)

$h^* \to Z \phi$ [UFO files from effective ggh coupling for kinematics and rescale rate with ggF cross section?]

• $\phi$ → $\mu\mu$

Similar strategy to the one above! In principle above 10 GeV we are safe from SM low mass resonances. Below 10 GeV? Also, how low can one go in mass by playing with muon isolation.

$h \to Z \phi$, $Z \to \mu\mu$, $\phi \to \mu\mu$ recasted from existing analysis of $h \to \phi \phi$, $\phi \to \mu\mu$.