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).

Please add your initials to sub-projects!

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 $\phi$: $\phi \to \gamma \gamma$, $\phi \to \mu \mu$

• $\phi$ → $\gamma\gamma$.

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

For m_a < 47 MeV, they put limits on very light ALPs () 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 for gg → h → Z $\phi$, and assume limits for 100 events at LHC

• $\phi$ → $\mu\mu$

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.

For $m_\phi > 35$ GeV:

$h \to Z^* \phi$, $Z^* \to \mu\mu$ [names: SG, AL, JN, GM]

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

For 47MeV < $m_\phi < 35$ GeV:

$h \to Z \phi$, $Z \to \mu\mu$, $\phi \to \gamma\gamma$ [names: SG, AL, JN, GM, KT]

$h \to Z \phi$, $Z \to \mu\mu$, $\phi \to \mu\mu$ recasted from existing analysis of $h \to \phi \phi$, $\phi \to \mu\mu$ [names: KT]