Les Houches

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Interested people: Jose Miguel No, Jose Zurita, Stefania Gori

1. V phi, with phi → gamma gamma, what does the LHC can say?

bounds from LEP. what is the LHC capability?

bounds from H coupling measurements to ZZ and EWPT

2. Complementarity with phi single production together with a ISR

Light scalars (m_{phi} < m_h = 125 GeV) with no phi V V coupling (V = SM gauge boson) but coupling to fermions. Motivated in extended Higgs sectors (e.g. light Higgses in 2HDM) when the 125 GeV is SM like (2HDM “alignment limit”).

Weakly constrained by LEP (no V phi production). Maybe challenging @ LHC? phi recoiling against a hard jet could allow to trigger on this (phi → gamma gamma? tau tau?).

3. Exotic Higgs decays: What are the holes?

h → a a, Z a, a a' with a, a' scalar/pseudoscalar (for Z a, a is pseudoscalar)

• Current searches for h → a a: 4 muon, 2 mu 2 b, 4 tau, 2 tau 2 mu, 4 b…
• Interesting to look at signatures with resolved/not resolved photons: 2b 2gamma, 4 gamma (for unresolved 2 gamma pairs, measurement of h→gamma gamma could yield weak constraint)
• h → Z a (a → gamma gamma) has been initially studied by Bauer, Neubert, Thamm in 1704.08207, for a being an ALP (axion-like particle)
• h → a a': if ma is different from ma', h → a a searches would miss it (also depends on final state)

h→chi1 chi2

• Decays involving MET? (e.g. chi1 invisible); (Also considerable for h → a a' and h → Z a)

Exotic Higgs decays into LLP (displaced vertices). Role of LHCb (also BaBar, Belle II)