From Higgs to Dark Matter 2014, Geilo

14 Dec 2014, 08:00 → 17 Dec 2014, 18:00 Europe/Zurich

Dr. Holms Hotel, Geilo, Norway

Anna Lipniacka (University of Bergen (NO))

Second Topical Meeting on Consequences of the Higgs Discovery for Dark Matter Searches

Dr. Holms Hotel, Geilo, Norway

Outline

This topical meeting follows the spirit of Nordic Particle Physics Meetings. It takes place in a traditional Norwegian mountain resort, this time in the famous Dr. Holms Hotel, Geilo, Norway. The scientific programme starts on Monday the 15th of December and ends on Wednesday the 17th of December. The travel days are the 14th and the 17th of December. The programme is composed of overview presentations and contributed talks on current topics in particle and astroparticle physics, with an emphasis on the consequences of the Higgs discovery for Dark Matter searches. The registration and abstract submission deadline is the 20th of November.

 

Speakers include

• Philip Bechtle, University of Bonn
• Laura Covi, University of Göttingen
• Oleg Lebedev, University of Helsinki
• Alexandre Arbey, CERN and Université de Lyon
• Ketevi Assamagan,  BNL
• Pierre Salati, Université de Savoie, Annecy
• Joe Silk, Université Pierre et Marie Curie, Paris
• Oscar Stål, Stockholm University
• Robert Wagner, Stockholm University

Travel information

To get to Geilo, take the train from Oslo or Bergen to Geilo train station. For international travelers it is recommended to fly  to Oslo Gardermoen or Bergen Flesland arriving on Sunday the 14th of December and then take a train to Geilo. The train trip takes ca. 3.5 hours and is following the scenic Oslo-Bergen train route. There are non-expensive flights to Oslo by Norwegian.no from many places in the world. There is a convenient KLM connection from Geneva via Amsterdam to either Oslo or Bergen: Flying to Bergen: On Sunday, e.g. KLM from Amsterdam arrives at Bergen airport at 13.20, and the train leaves from Bergen city centre at 15.59. On Wednesday, the train leaves from Geilo at 11.57 and arrives at Bergen city centre at 14.59. KLM to Amsterdam leaves from Bergen Airport at 17.20. Flying to Oslo: On Sunday, e.g KLM from Amsterdam arrives at Oslo airport at 12.10, and the train to Geilo leaves from Oslo Central Station at 15.25. On Wednesday, the train leaves from Geilo at 10.56 and arrives at Oslo Central Station at 14.45. The KLM flight to Amsterdam leaves at 17.15. There are of course many other possibilities to fly to Oslo or Bergen as well, flying with SAS or Norwegian.no, or with KLM directly from e.g. Paris CDG to Oslo. The connection between Bergen Airport Flesland and the train station can be realized by the airport bus (around 25min, every 15min), which stops 50m from the train station, or with a taxi (around 20min). From Oslo Airport Gardermoen there is a normal train as well as an Airport train leaving to Oslo Central Station, from where the train to Geilo leaves. Train tickets to Geilo can be booked here.   Follow the scenic train route from Bergen to Oslo on YouTube. Geilo is close to half way.

Conference fee

A conference fee of 4900 NOK (around 720 CHF) covers hotel with full board. It can be paid directly via this webpage, or in the hotel. Click on e-payment.

Accommodation

Accommodation was pre-booked in single rooms, full board for 25 participants, and it will be organized for you once you register.

Local organizing committee

• Anna Lipniacka (University of Bergen)
• Per Osland (University of Bergen)
• Jörn Kersten (University of Bergen)
• Heidi Sandaker (University of Bergen)
• Torsten Bringmann (University of Oslo)
• Therese Sjursen (University of Bergen)

Recent Nordic conferences in particle physics

Spaatind 2014 (org Lund); Spaatind 2012 (org NBI); From Higggs2DM 2012; Spaatind 2010 (org Bergen); Spaatind 2008 (org Helsinki); Spaatind 2006 (org Sweden); Spaatind 2002 (org Oslo)

 

Facility Excellent cross country skiing. Good downhill slopes. Beautiful spa facilities and swimming pool in the hotel.

 

photo nr 1 image.jpg

Poster Poster_FromHiggs2DM_2014.pdf

Sunday, 14 December

20:00 Dinner

Registration

Monday, 15 December

07:30 Breakfast

Welcome and Practicalities

The State of the Higgs

1 SM Higgs measurements and prospects

A detailed review of the latest results on the main properties of the Higgs boson using approximately 25 fb-1 of pp collision data collected at 7 TeV and 8 TeV in 2011 and 2012, will be given. The measurements of the mass, couplings properties and main quantum numbers will be presented. Prospects for the next LHC Run starting in 2015 will be reviewed.

Speaker: Ketevi Adikle Assamagan (Brookhaven National Laboratory (US))

Slides HiggsToDarkMatter_KeteviAssamagan.pdf

2 Overview of SM Higgs measurements at CMS and constraints on DM from Higgs searches

An overview of Higgs boson results from CMS is presented using pp collision data collected at centre-of-mass energies of 7 and 8 TeV corresponding to integrated luminosities of 5/fb and 20/fb respectively. The combination of the coupling results of all Higgs boson decay channels measured at CMS is presented with various fits looking for deviations of the couplings from the Standard Model predictions. Measurement of Higgs boson mass from combination of 4-lepton and $\gamma\gamma$ channel is presented. Studies of the Higgs boson spin and parity are presented using data samples corresponding to the $\gamma \gamma$, $ZZ$, and $WW$ decay channels. The data are compared to the expectations for a Standard Model Higgs boson, and for several alternative models. Constraints on the total Higgs boson width, $\Gamma_H$, are presented using off-shell production and decay in the ZZ channel. The analyses are carried out in the ZZ to 4-lepton and to 2-lepton-2-neutrino channels, and constraints on the Higgs boson width are obtained. A search for Higgs boson invisible decay modes has been carried out in events where the Higgs boson is produced in association with a $Z$ boson as well as through Vector Boson Fusion. In the associated production search, electron, muon and $b$-quark pair decay modes of the $Z$-boson are considered. No evidence of a signal has been found and upper limits on the invisible branching ratio are obtained and interpreted in a Higgs portal model of dark matter interactions.

Speaker: Roko Plestina (Chinese Academy of Sciences (CN))

Slides Geilo2014_prezi_plestina.pdf http://prezi.com/glohv-oivlnx/?utm_campaign=share&utm_medium=copy

10:15 Coffee Break

The State of the Higgs

3 Overview of BSM Higgs measurements at LHC, and prospects for the LHC high Energy run

After the discovery at the LHC in 2012 of a scalar boson with a mass of 125 GeV, which has been found to be an ideal Higgs boson candidate, it is fundamental to understand not only the properties of such particle, but the structure of the whole Higgs sector itself. Several SM extensions (BSM models) predict the existence of additional Higgs bosons which should also couple to the SM particles, hence several searches for additional scalar, pseudoscalar, neutral and charged Higgses are ongoing at the LHC. In this talk are presened the recent results from the ATLAS and CMS experiments in the search for BSM Higgses using the data collected at 7 TeV and 8 TeV and the prospects for the upcoming data-taking runs, starting in 2015.

Speaker: Matteo Bauce (Universita e INFN, Roma I (IT))

Slides Bauce_BSMHiggs.pdf

11:30 Ski & Lunch Break

Multi-Higgs Models

4 The two Higgs doublet model with and without dark matter

Speaker: Oscar Stål (DESY)

Slides OS_2HDM.pdf

5 Extending 2HDM by a singlet scalar field - the case for dark matter

We extend the two-Higgs doublet models of Type I and Type II by adding a real gauge-singlet scalar $S$ which is the Dark Matter (DM) candidate (2HDMS models). We impose theoretical constraints derived from perturbativity, stability, unitarity and correct electroweak symmetry breaking and require that the lightest CP-even Higgs, $h$, fit the LHC data for the $\sim 125.5$ GeV state at the $68\%$~C.L. after including existing constraints from LEP and $B$ physics and LHC limits on the heavier Higgs bosons. We find that these models are easily consistent with the LUX and SuperCDMS limits on DM-Nucleon scattering and the observed DM abundance for $S$ masses above about $55$ GeV. At lower $m_S$, the situation is more delicate. For points with $m_S$ in the $6-25$ GeV range corresponding to the CDMS II and CRESST II positive signal ranges, the DM-Nucleon cross sections predicted by the Type I and Type II models more or less automatically fall within the $95\%-99\%$ C.L. signal region boundaries. Were it not for the LUX and SuperCDMS limits, which exclude all (almost all) such points in the case of Type I (Type II), this would be a success for the 2HDMS models. In fact, in the case of Type II there are a few points with $5.5 {\rm ~GeV} < m_S < 6.2 {\rm ~GeV}$ that survive the LUX and SuperCDMS limits and fall within the CDMS II 99% C.L. signal region. Possibilities for dark matter to be isospin-violating in this 2HDMS context are also examined.

Speaker: Bohdan Grzadkowski (University of Warsaw)

Slides Geilo_2014_Grzadkowski.pdf

6 Scalar dark matter and possible implications at the LHC

I shall review an extension of the Inert Dark Matter model, that also allows for CP violation in the scalar sector. This kind of model contains charged scalars that could be produced at the LHC, and emit SM particles via virtual W or Z emission in its decay to dark matter.

Speaker: Prof. Per Osland (University of Bergen (NO))

Slides osland-geilo.pdf

7 Three Higgs doublet models with S3 symmetry and dark matter candidates

I shall report on work in progress in the framework of three Higgs doublets with an S3 symmetry providing a dark matter candidate. This is still very preliminary and I shall focus on the main questions we want to address.

Speaker: Margarida Nesbitt Rebelo (Instituto Superior Tecnico (IST))

Slides mnrgeilo14.pdf

8 Search for Scalar Charm Pair Production with the ATLAS Detector in pp Collisions at sqrt(s) = 8 TeV

Supersymmetry (SUSY) is a theoretically attractive extension to the Standard Model of particle physics with the potential to solve several of its theoretical problems. For instance, the nature and production of dark matter is explained in SUSY by the existence of new stable, weakly interacting particles. A search for the production of supersymmetric partners of the charm quark will be presented, using data collected in 2012 with the ATLAS detector at the LHC. This is a previously unexplored SUSY scenario, the search for which makes use of recent developments in charm tagging algorithms and charm-tags the leading two jets in an event, significantly enhancing the sensitivity for this signal over inclusive searches. The results are used to set limits on the visible cross section of new physics, and are interpreted in a specific simplified model with only supersymmetric charm quarks and the neutralino LSP (lightest SUSY particle) kinematically accessible at the LHC.

Speaker: William Kalderon (University of Oxford (GB))

17:05 Coffee Break

Dark Matter and the LHC

9 Interplay of LHC and dark matter searches in the MSSM

The Minimal Supersymmetric extension of the Standard Model (MSSM) provides suitable candidates for Dark Matter. In this talk, I will discuss the constraints from Dark Matter direct detection, Planck results and LHC SUSY, Higgs and monojet data, and show that complementary of the different sectors is of importance to probe the pMSSM parameter space.

Speaker: Alexandre Arbey (Lyon U.)

Slides Arbey_Geilo_Dec14.pdf

10 Overview of dark matter searches at CMS

This talk reviews the latest Dark Matter (DM) results from the CMS experiment, consisting in searches for DM particles under the form of Weakly Interactive Massive Particles. The search for directly produced DM particles exploits final states containing a high momentum single object and missing transverse energy, such as monojet, monophoton, monolepton and monotop. The production of DM particles in association with top quarks is also considered. Finally, the search for invisible decays of the Higgs bosons and their DM results are mentioned as well.

Speaker: Saeid Paktinat Mehdiabadi (School of Particles and Accelerator Inst. for Res. in Fundam. S)

Slides DM_CMS_Saeid_Paktinat_Geilo2014_2.pdf DM_CMS_Saeid_Paktinat_Geilo2014_2.pptx

11 SUSY DM: ATLAS Discovery Potential for 2015

We scan the 19 parameter pMSSM in search of experimentally viable models which can potentially be discovered by ATLAS during Run 2.

Speaker: Jan Oye Lindroos (University of Bergen (NO))

Slides Geilo14_Lindroos.pdf

12 Minimal models for decaying Dark Matter and the LHC

We introduce minimal models of decaying Dark Matter, characterized by the fact that DM interacts with SM particles through one renormalizable coupling with an additional heavier SM charged state. Such interaction allows to produce a substantial abundance of DM in the early Universe via the decay of the charged heavy state, either in- or out-of-equilibrium. Moreover additional couplings of the charged particle open up decay channels for the DM, which can nevertheless be sufficiently long-lived to be a good DM candidate and within reach of future Indirect Detection observations. We discuss possible signals at the LHC in the cosmologically favored parameter region and comment on the possibility to obtain in such models the recently observed 3.55 keV X-ray line.

Speaker: Laura Covi (Goettingen University)

Slides DecayingDM-Geilo14.pdf

20:00 Dinner

21:00 Dr. Holms Hotel, Movie

A movie about the history of the hotel (in Norwegian)

Tuesday, 16 December

07:30 Breakfast

Higgs Portal Models

13 The Higgs Portal

I will discuss some aspects of the Higgs portal models, in particular, their cosmological implications as well as possible signatures at the LHC.

Speaker: Oleg Lebedev (University of Helsinki)

Slides geilo.pdf

14 First order electroweak phase transition and dark matter in (non)conformal Higgs portal models

We study the electroweak phase transition in class of classically (non)conformal Higgs portal models, with and without Veltman conditions imposed for the scalar sector. Some of the models include also fermionic type dark sector, which can be related to dark matter or neutrino masses. We find, by scanning the model parameter spaces,many realizations of the models, where the electroweak phase transition is strongly first order. The portal coupling is usually large in these cases, and particularly the Veltman conditions reduce suitable parameter space significantly. We impose constraints for the models, analyse the aspects of the fermionic dark sectors, and discuss about further analysis prospects.

Speaker: Jussi Virkajärvi (urn:Google)

Slides Geilo_virkajarvi.pdf

10:05 Coffee Break

Dark Matter and the LHC

15 Explaining a CMS dilepton excess with the MSSM golden cascade

Recently CMS reported a small excess in a search for opposite-sign same-flavor leptons produced in conjunction with two jets and missing transverse momentum. The excess was found to be consistent with a kinematic edge in the invariant mass spectrum of the leptons. We present a possible interpretation of this excess in terms of squark pair production followed by a ‘golden cascade’ decay for one of the squarks, producing the edge in the dilepton spectrum. We identify models that fit the observed event rate while still passing other collider constraints, and present predictions for the production cross section at 13 TeV. Some of the identified models also predict a relic density of neutralino dark matter compatible with the value inferred from cosmological observations.

Speaker: Anders Kvellestad (University of Oslo)

Slides Kvellestad_Geilo.pdf

16 Constraints on Dark Matter from ATLAS mono-X + missing energy searches

The ATLAS experiment at CERN performs several dedicated searches for Dark Matter production, using mono-jet plus missing energy signals and mono-X plus missing energy where X can be for instance a W or Z boson or a photon. The latest constraints on Dark Matter from these searches are presented and include limits derived from search for Higgs to invisible decays.

Speaker: Christophe Clement (Stockholm University (SE))

Slides Presentation_v2.pdf

17 On the way to the Dark Matter simplified models for Run-2

Both ATLAS and CMS have been using effective field theory approach to describe their results in terms of the DM pair-production in Run-1. Whereas the effective field theory is well applicable in the case of the direct detection experiments, it is facing severe criticism when used at colliders where the actual inferred limits on the suppression scale are comparable to the centre-of-mass energy. I will report on the recent works and on the ongoing effort to define a set of simplified models that ATLAS and CMS shall be using in Run-2.

Speaker: David Salek (NIKHEF (NL))

Slides Geilo_Salek.pdf

11:35 Ski & Lunch Break

The Higgs, Dark Matter and Cosmology

18 Higgs measurements and global fits

Speaker: Philip Bechtle (Deutsches Elektronen Synchrotron (DESY))

Slides PBe_HiggsAndDarkMatterGeilo141216.pdf

19 B-factory searches for light scalars and other new states

New Higgs scalars with masses up to 10 GeV are predicted in models such as NMSSM, and in scenarios with hidden sectors that couple weakly to the Standard Model. Searches at B factories have resulted in tight constraints on such models. The talk will cover the recent searches and new results, and discuss the future outlook for this physics.

Speaker: Prof. Roger Barlow (MANCHESTER UNIVERSITY)

Slides talk.pdf

20 Looking for dark matter in exotic Higgs decays at the LHC

The particle nature of dark matter is one of the most intriguing questions in particle physics. The discovery of a fundamental scalar particle compatible with the Higgs boson predicted by the SM paves the way for probing this question with new methods. An overview of the LHC Run-I legacy results in looking for both exotic Higgs decays with dedicated searches and invisible Higgs decays is presented in this contribution. Interpretations in terms of dark matter searches are discussed and prospects for Run-II searches are overviewed.

Speaker: Andrea Coccaro (University of Washington (US))

Slides 2014-12-16-coccaro.pdf

21 Ultra high-energy cosmic rays: present and future

Recent progress on the field of ultra high-energy cosmic rays (UHECR) has been driven by the data colected by the Pierre Auger Observatory in the southern hemisphere and by Telescope Array (TA) in the northern hemisphere. These hybrid observatories combine large ground arrays with fluorescence detection techniques. In this presentation, selected results from Auger and TA will be reviewed. Challenges and prospects for the future will then be addressed.

Speaker: Catarina Espirito Santo (LIP)

Slides Geilo2014-CatES.pdf

22 Inflationary Imprints on Dark Matter

A generic feature of Standard Model extensions with no drastic modifications to the Higgs potential is that the Higgs is a light and energetically subdominant field during inflation. Inflationary fluctuations generically displace the field from its vacuum generating a primordial Higgs condensate. This sets specific out-of-equilibrium initial conditions for the hot big bang epoch which could have significant observational ramifications. In this work we investigate how these initial conditions set by inflation affect the generation of dark matter in the class of portal scenarios where SM fields feel new physics only through Higgs mediated couplings. As a representative example we will consider a $Z_2$ symmetric scalar singlet $s$ coupled to Higgs by $V = \lambda \Phi^{\dagger} \Phi s^2$. This simple extension has interesting consequences as the singlet constitutes a dark matter candidate originating from non-thermal production of singlet particles out from a singlet condensate.

Speaker: Mr Tommi Tenkanen (University of Helsinki and Helsinki Institute of Physics)

Slides From_Higgs_to_DM_Tommi_Tenkanen.pdf

17:05 Coffee Break

Indirect Dark Matter Searches

23 Dark matter, cosmic rays and the Higgs boson : an update

Although the existence of the astronomical dark matter is by now well established, its nature is still unresolved. The favoured candidate is a massive and weakly interacting neutral particle, dubbed WIMP, whose relic abundance is compatible with cosmological measurements. If present inside the haloes of galactic systems, these species still annihilate and yield distortions in the various cosmic radiations which a plethora of experiments are searching with increasing accuracy. I will review the status of the current searches. In particular, I will discuss the recently confirmed high-energy positron anomaly as well as the yet unexplained GeV gamma-ray excess from the Galactic center. Antiprotons yield also severe bounds on WIMP properties which may turn out to be crucial. I will finally elaborate on the still remote connections between dark matter indirect searches and the Higgs boson.

Speaker: PIERRE SALATI (LAPTh and Université de Savoie)

Slides geilo_141216_salati.pptx

24 Constraining Inert Triplet Dark Matter by the LHC and FermiLAT

We study collider phenomenology of inert triplet scalar dark matter at the LHC. We discuss possible decay of Higgs boson to dark matter candidate and apply current experimental data for invisible Higgs decay and $R_{\gamma\gamma}$ to constrain parameter space of our model. We also investigate constraints on dark matter coming from forthcoming measurement, $R_{Z\gamma}$ and mono-Higgs production. We analytically calculate the annihilation cross section of dark matter candidate into $2\gamma$ and $Z\gamma$ and then use FermiLAT data to put constraints on parameter space of Inert Triplet Model. We found that this limit can be stronger than the constraints provided by LUX experiment for low mass DM.

Speaker: Dr Seyed Yaser Ayazi (IPM)

Slides From_Higgs_to_DM.pdf

25 Antideuterons from Dark Matter and Hadronization uncertainties

Due to its low astrophysical background, the antideuteron channel is a highly promising channel for indirect detection of dark matter. Being an antinucleus, the antideuteron flux has additional uncertainties from the nucleus formation model that are not relevant for other indirect detection channels. The antideuteron formation model depends on very small momentum differences between antinucleons, making it highly sensitive to two-particle correlations arising from the hadronization models employed by Monte Carlo event generators. I will here discuss the influence of hadronization on antideuteron formation, and the uncertainty on the antideuteron flux this leads to. I will further discuss the prospects of reducing this uncertainty by tuning Monte Carlo generators specifically for antideuteron production.

Speaker: Lars Andreas Dal (University of Oslo)

Slides Antideuterons_Dal

26 High-energy gamma-ray astronomy and dark matter searches with Imaging Air Cherenkov observatories: Status and prospects

In recent years, ground-based very-high energy (E>50 GeV) gamma-ray instruments like H.E.S.S., MAGIC, and VERITAS have taken on a major role in high-energy astrophysics. The high sensitivity and performance parameters, still far from the limits of the observation technique though, have lead to the detection and enabled studies of more than 100 sources of various source populations. The instruments are also well suited for the indirect searches for dark matter and have conducted major search programs in the last years. Building on their success, Cherenkov Telescope Array (CTA) is a project for a next-generation observatory for very high energy (GeV-TeV) ground-based gamma-ray astronomy, currently in its design phase, and foreseen to be operative a few years from now. In the talk, the observation technique and current status of the field is reviewed and selected recent scientific results are highlighted. I will also review the status of dark matter searches and prospects for CTA.

Speaker: Robert Wagner (Stockholm University)

Slides Wagner_IDM_CTA

20:00 Dinner

Wednesday, 17 December

07:30 Breakfast

Indirect Dark Matter Searches

27 Strategy for the ATLAS pMSSM summary effort

The strategy for the ATLAS pMSSM summary effort, which will lead to one of the so-called legacy papers of the collaboration, is presented. A flat scan of the pMSSM parameter space is performed by Tom Rizzo, an ATLAS short term associate. Various constraints are imposed for the scan to select viable models. A broad selection of searches in ATLAS is implemented. The selected models are first evaluated at event generation level in order to select a set we are likely to just about exclude. These will be simulated with AtlFast-II. The goals of the effort are to evaluate the impact of SUSY searches on a large set of pMSSM models, show the reach and complementarity of the searches, identify and classify models that are not excluded. A section is dedicated to the impact of ATLAS on dark matter. As the paper is still in a preliminary stage, no results have been approved for the public.

Speaker: Lillian Smestad (University of Bergen (NO))

Slides LillianSmestad_FromHiggsToDM_Geilo2014.pdf

28 Gamma Rays from Dark Matter Self-annihilations and Black Holes

Speaker: joseph silk (IAP)

Conference Summary

10:10 Coffee break

10:30 Check-Out

12:30 Lunch