PITT PACC Workshop: Invisible Higgs at the LHC

24 Aug 2016, 07:50 → 26 Aug 2016, 16:50 US/Eastern

University of Pittsburgh

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

ADMINISTRATOR: Cindy Cercone

Wednesday 24 August

13:00 → 15:15 ATLAS discussions

https://indico.cern.ch/event/549966/

15:15 → 15:45 Coffee break

15:45 → 18:00 ATLAS discussions

https://indico.cern.ch/event/549966/

18:00 → 18:30 Dinner break

18:30 → 20:00 ATLAS discussions

https://indico.cern.ch/event/549966/

Thursday 25 August

08:30 → 12:00 ATLAS discussions

https://indico.cern.ch/event/549966/

12:00 → 13:00 Lunch at the University Club Dining Area

13:00 → 19:00 Experiment-Theory Joint Session

13:00 Welcome + Information

Speakers: Brian Thomas Batell (University of Pittsburgh (US)), Tae Min Hong (University of Pittsburgh (US))

TMHong_PITTPACCWorkshop_Welcome.pdf

13:10 Experiment: Overview + DM

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))

madssen.pdf

13:40 Experiment: Progress in VBF invisible Higgs

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)

Pittsburgh_SeminarHinv_August25_2016_v2.pdf

14:10 Discussion Overflow + Coffee Break

14:30 Theory: Motivation

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

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)

Berlin_VBF_PITT_2016.pdf

15:50 Discussion Overflow + Group Photo (go outside) + Coffee Break

16:20 Theory: Invisible Higgs in ZH + VBF

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

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

Friday 26 August

08:00 → 08:30 Breakfast

08:30 → 09:30 ATLAS discussions

https://indico.cern.ch/event/549966/

09:30 → 10:00 Coffee break

10:00 → 12:00 ATLAS discussions

https://indico.cern.ch/event/549966/