PITT PACC Workshop: Invisible Higgs at the LHC

University of Pittsburgh

University of Pittsburgh

Pittsburgh, PA 15260

This workshop will bring together experts from experiment and theory to discuss and develop new opportunities to study the invisible decay of the Higgs boson using VBF.

The ATLAS discussions are at: https://indico.cern.ch/e/549966/

LOCAL ORGANIZERS: Brian Batell, Tao Han, Tae Min Hong


  • Alexander Madsen
  • Andrew White
  • Ayres Freitas
  • Ben Carlson
  • Brian Thomas Batell
  • Dorival Goncalves
  • Elliot Lipeles
  • Han Yuan
  • Ketevi Adikle Assamagan
  • Rui Zou
  • Satyanarayan Mukhopadhyay
  • Tae Min Hong
  • Thi Ngoc Loan Truong
  • William Balunas
  • Xing Wang
  • Yongcheng Wu
    • 13:00 15:15
      ATLAS discussions


    • 15:15 15:45
      Coffee break 30m
    • 15:45 18:00
      ATLAS discussions


    • 18:00 18:30
      Dinner break 30m
    • 18:30 20:00
      ATLAS discussions


    • 08:30 12:00
      ATLAS discussions


    • 12:00 13:00
      Lunch at the University Club Dining Area 1h
    • 13:00 19:00
      Experiment-Theory Joint Session
      • 13:00
        Welcome + Information 10m
        Speakers: Brian Thomas Batell (University of Pittsburgh (US)) , Tae Min Hong (University of Pittsburgh (US))
      • 13:10
        Experiment: Overview + DM 30m

        Searches for invisible decays of the Higgs boson at the LHC

        In this talk I will present an overview of searches for invisible decays of the Higgs boson undertaken at the ATLAS and CMS experiments. I will review recent results from direct searches for invisible decays as well as constraints from measurements of visible decay widths, and discuss available combinations and interpretations.

        Speaker: Alexander Madsen (Deutsches Elektronen-Synchrotron (DE))
      • 13:40
        Experiment: Progress in VBF invisible Higgs 30m

        Search for Higgs to invisible using vector boson fusion

        The search for invisible decays of the Higgs boson is most sensitive in the vector boson fusion channel. This talk will cover experimental aspects of the search for Higgs to invisible, with emphasis VBF. I will begin with an overview of techniques used in run 1, then discuss planned improvements for run 2. This will include an updated optimization procedure, trigger strategies and the impact of pileup. The talk will conclude with a discussion of a few alternative models that serve as indicators of additional signal regions to consider.

        Speaker: Benjamin Taylor Carlson (University of Pittsburgh)
      • 14:10
        Discussion Overflow + Coffee Break 20m
      • 14:30
        Theory: Motivation 40m

        The talk will be divided into three parts. First, I will review the classic Eboli-Zeppenfeld analysis and show how it can be improved using an extended set of observables. This will in particular lead us to the question how well we understand relatively soft central jets. Next, I will show how we can include invisible Higgs decays in a global Higgs and gauge sector analysis based on SFitter. Finally, I will give an example for a model which predicts large invisible branching ratios for an otherwise SM-like Higgs boson. It aims to rather naturally explain the Fermi galactic center excess in the NMSSM and predicts invisible Higgs branching ratios easily in the reach of early Run II analyses.

        Speaker: Tilman Plehn
      • 15:10
        Theory: VBF Neutralino & EW DM 40m

        Dark Matter in Vector Boson Fusion

        VBF is a promising probe for dark matter that interacts with the electroweak sector. In this talk, I will discuss several different manifestations of such models and the potential reach of VBF searches at high-energy colliders.

        Speaker: Asher Berlin (University of Chicago)
      • 15:50
        Discussion Overflow + Group Photo (go outside) + Coffee Break 30m
      • 16:20
        Theory: Invisible Higgs in ZH + VBF 40m

        The direct invisible Higgs bounds are driven by two main searches at hadron colliders: WBF and ZH. For the WBF, we will present some recent progress made on the Monte Carlo modelling and show the prospects of this measurement at the 100 TeV Nimatron. For the ZH, we will show that loop-induced components for both the signal and background present phenomenologically relevant contributions to invisible limits. In addition, we derive the constraining power of this channel to Simplified Models for Dark Matter with scalar and pseudo-scalar mediators.

        Speaker: Dorival Goncalves Netto (Heidelberg University)
      • 17:00
        Theory: Higgs-DM portals 40m

        Identifying the Nature of Dark Matter via Higgs portal.

        There are three types of the models depending on the DM spin: scalar, fermion and vector DM models. In this talk, we consider renormalizable, unitary and gauge invariant Higgs portal DM models. For the Higgs portal singlet fermion and vector DM cases, the force mediator involves two scalar propagators, the SM-like Higgs boson and the dark Higgs boson. We will show that their interference generates interesting and important patterns in the mono-Zplus missing energy signatures at the ILC and LHC. In addition, we will further show that with VBF search strategies it will be possible to distinguish between Higgs portal DM from canonical wino DM scenarios at the LHC.

        Speaker: Tathagata Ghosh (Texas A&M University)
      • 17:40
        Discussion Overflow 20m
    • 08:00 08:30
      Breakfast 30m
    • 08:30 09:30
      ATLAS discussions


    • 09:30 10:00
      Coffee break 30m
    • 10:00 12:00
      ATLAS discussions