Neutrinoless double beta decay search in Xe - next-generation experiment workshop

Name: Neutrinoless double beta decay search in Xe - next-generation experiment workshop
Start: 2025-11-12T07:55:00-05:00
End: 2025-11-14T21:00:00-05:00
Location: Montreal

12 Nov 2025, 07:55 → 14 Nov 2025, 21:00 America/Toronto

Thomson House Ballroom (Montreal)

Thomson House Ballroom

Montreal

Thomson House 3650 McTavish St Montreal, QC H3A 1X1

Roxanne Guenette (University of Manchester), Thomas Brunner (McGill and TRIUMF)

Description

The search for neutrinoless double beta decay, ideally in more than one isotope, has been identified as high priority by the international subatomic physics community. Over the past decades, significant advancements have been made in the development of xenon TPCs.

Proposed next-generation experiments intend to deploy tonne(s) of the double beta decaying isotope Xe-136 and are expected to reach sensitivities in the mid-10^27 to 10^28 years range. The complexity of these experiments and the cost of xenon likely will limit the number of next-generation experiments and their timescales.

We are organizing a workshop to discuss possibilities and opportunities for a coherent collaborative effort to search for neutrinoless double beta decay in Xe-136. We want to keep this workshop as inclusive and as broad as possible and are inviting possible collaborators with the aim of creating a new consortium or collaboration under a new name with the broad goal of developing a roadmap for a competitive search for neutrinoless double beta decay using xenon as a target medium.

The workshop will be held November 12-14, 2025 in Montreal.

Thomson House Ballroom
3650 McTavish St
Montreal, QC H3A 1X1

All zoom sessions: https://mcgill.zoom.us/my/xe0vbbws

Organizing committee:
Thomas Brunner
Roxanne Guenette
Mike Heffner
Ben Jones
Justo Martin-Albo
Fran Spidle

With the kind sponsorship from:

and with entertainment by Les Restants d’Cabane:

Registration

Registration Information Next Gen Xe workshop

Participants

Ako Jamil
Alex Todd
Alex Wright
Amelia Remnant
Andrea Pocar
ANKIT GAUR
Annika Lennarz
Antoine Amy
Art McDonald
Ben Jones
Bill Fairbank
Brais Palmeiro Pazos
Brian Lenardo
Brian Mong
Caio Licciardi
Chloé Malbrunot
Christine Kraus
Daniel Akerib
Darren Grant
Dave Hawkins
David Asner
David Gallacher
David Moore
David Sinclair
Eleanor Allen
Eric Church
Eric Dahl
Erica Caden
Ethan Coulthard
Fabrice Retiere
Fran Spidle
Francesc Monrabal Capilla
Frédéric Girard
Gabriel Orebi Gann
Giorgio Gratta
Guillaume Giroux
Hossein Rashidi
Hugh Lippincott
Hussain Rasiwala
Irina Nitu
Isaac Arnquist
Jason Holt
Jessica Provenz
Jianglai Liu
Joaquim Palacio Navarro
Jodi Cooley
Jose Angel Hernando Morata
Jose F. Toledo
Juan Jose Gomez Cadenas
Julien Masbou
Justo Martín-Albo
Kaixuan Ni
Kevin Gracequist
Krishan Mistry
Krishna Kumar
Kyle Leach
Liang Yang
Lucas Darroch
Michela Lai
Michelle Dolinski
mike heffner
Naman Walia
Nasim Fatemighomi
Nigel Smith
Pablo Herrero Gomez
Pau Novella
Raheema Hafeji
Ray Bunker
Regan Ross
Richard Saldanha
Rituparna Kanungo
Riya Rai
Roxanne Guenette
Samin Majidi
Samuele Sangiorgio
Sean Paling
Simon Lavoie
Simon Viel
Spencer Axani
Stefano Roberto Soleti
Stephen Sekula
Tania Atoui
Teena Vallivilayil John
Thomas Brunner
Tim Daniels
Tony Noble
Tsvetelin Totev
Zepeng Li

Contact

xe-0vbb@physics.mcgill.ca

Wednesday, 12 November
- 08:30 → 09:00
  
  Pre-Registration All zoom sessions: https://mcgill.zoom.us/my/xe0vbbws
  
  All zoom sessions: https://mcgill.zoom.us/my/xe0vbbws
- 09:00 → 10:00
  Introduction, goals and context (Chair: Hugh Lippincott)
  
  Chair: Hugh Lippincott
  - 09:00
    
    Welcome/Logistics 15m
    
    Speaker: Dr Thomas Brunner (McGill U)
    
    20251112-Xe-0vBB-welcome.pdf 20251112-Xe-0vBB-welcome.pptx
  - 09:15
    
    Welcome to McGill 10m
    
    Speaker: Dr Kristina Öhrvall (McGill University)
  - 09:25
    
    Workshop Goals 35m
    
    Speaker: Dr Roxanne Guenette (University of Manchester)
    
    Guenette_0nbb_Workshop_Montreal_2025.pdf
- 10:00 → 10:30
  
  Break - At the venue - light food and drink provided 30m
- 10:30 → 12:00
  Status of the field (Chair: Michelle Dolinski)
  
  Chair: Michelle Dolinski
  - 10:30
    
    Review of the xenon technologies 30m
    
    Speaker: Dr Mike Heffner (LLNL)
    
    xenonTechnologies-v4.pdf
  - 11:00
    
    Best current limits using 136Xe 30m
    
    Speaker: Dr Spencer Axani
    
    2025 Workshop -- KamLAND-Zen -- saxani .pdf
  - 11:30
    
    The Chinese Xenon programme 30m
    
    Speaker: Dr Jianglai Liu
    
    PandaX-DBD-workshop.pdf
- 12:00 → 13:30
  
  Lunch - provided 1h 30m
  
  soup, sandwich and salad options
- 13:30 → 15:00
  Theory discussions of 0nbb: (Chair: Liang Yang)
  - 13:30
    Theory review of the nuclear matrix element calculation for 136Xe 30m
    
    Speaker: Dr Jason Holt (TRIUMF)
    
    Holt_Xe.pdf Holt_Xe.pptx
    
    Question period 10m
  - 14:00
    
    Accessing underground labs 30m
    
    Speaker: Dr Erica Caden (SNOLAB)
    
    BuildAtSNOLAB_ExtraSlides_Caden_XeWkshp.pdf
  - 14:30
    
    Technical Coordination of large-scale 0nbb experiments 30m
    
    Speaker: Dr Francesc Moranbal
    
    CanadaWorkshop-2.pdf
- 15:00 → 15:30
  
  Break 30m
- 15:30 → 16:30
  Technical challenges and new ideas: (Chair: Nigel Smith)
  - 15:30
    
    Radioassay needs for future low-bkg experiments 30m
    
    Speaker: Dr Isaac Arnquist (Pacific Northwest National Laboratory)
    
    Radioassay_0VBB Montreal Workshop_2025_Arnquist.pptx
  - 16:00
    
    Low radioactivity materials 30m
    
    Speaker: Dr Richard Saldanha
    
    Saldanha_Montreal_Workshop_2025.pdf
- 16:30 → 17:54
  Blue Sky Session: (Chair: Nigel Smith)
  - 16:30
    
    Shielding and Outer Detectors 14m
    
    Cosmogenic muons are a major background source in rare event search experiments. To mitigate this background, neutrinoless double beta decay ($0\nu\beta\beta$) and direct detection dark matter experiments prefer to operate in deep underground laboratories, where they can receive adequate shielding from cosmic rays. However, high energy muons can still reach underground and create backgrounds for these experiments. To reduce such cosmogenic muon backgrounds, the rare-event search experiments deploy an outer detector to tag the muons. The outer detector can act as a muon veto. An active muon veto detects light produced either via Cherenkov radiation (if the detector is filled with the water) or scintillation light (if the detector is filled with the scintillation medium). The outer detector is instrumented with photon detection modules, such as photomultiplier tubes (PMTs) or silicon photo multipliers (SiPM). In addition, the outer detector can also serve as passive shielding, moderating secondary neutrons produced by muon interactions. In this talk, I will discuss about requirements of the deep underground laboratories, and the specifications of the outer detectors for the current and future rare event search experiments.
    
    Speaker: Dr Teena Vallivilayil John (Postdoc)
    
    Shielding and Outer Detectors.pdf
  - 16:44
    
    What is the limit of topological background rejection with a gas TPC? 14m
    
    Gaseous xenon time projection chambers (GXeTPC) are an excellent detector technology for reducing radiogenic backgrounds in $0\nu\beta\beta$ decay searches due to the extended beta tracks. The signal consists of two emitted beta electrons with 2.45 MeV of energy, and their track lengths scale inversely with the gas pressure, reaching ~2 m in size for 1 bar of gas pressure or ~20 cm at 10 bar. The most significant backgrounds that can mimic this signature are gamma rays originating from radiogenic sources or beta decays from cosmogenically activated isotopes such as Xe-137. Such backgrounds generally produce a single electron signature, and GXeTPCs can reject a significant fraction of them using the amount of energy deposition near the track ends and event multiplicities. In this talk, I will be discussing how GXeTPCs can best use the topological information to reject these backgrounds, including the use of new variables that exploit the angular information of the tracks, and what factors can limit this.
    
    Speaker: Dr Krishan Mistry (University of Texas at Arlington)
    
    GasTPCTopo_Mistry.pdf
  - 16:58
    
    Are five tonnes of xenon enough? 14m
    
    Target mass is a key consideration in optimizing the design of a future neutrinoless double beta decay detector with xenon. This short talk makes the case that in the current context, to achieve our scientific goals, a target mass larger than 5 tonnes needs to be considered seriously.
    
    Speaker: Dr Simon Viel (Carleton University)
    
    sviel_0vbb_nov12.pdf
  - 17:12
    
    Reaching the Normal Hierarchy for double beta decay 14m
    
    To reach the Normal Hierarchy and thus definitively address the question of lepton number conservation, current background levels must be reduced by a factor of ~1000 and some of this must come from improved energy resolution. I suggest this might be achieved in liquid xenon by a series of fundamental changes in design to include (a) the use of low IP additives such as TEA to allow much higher detection efficiency together with charge and light measurements on each charge cluster, (b) the use of fine pixelated detectors, (c) positive ion detection to reduce diffusion and preserve electron track information and (d) improved high voltage design to allow operation at higher fields. Work on this should be done globally with the aim of a global detector approach.
    
    Speaker: Dr David Sinclair (Carleton University)
    
    Sinclair-McGill workshop.pptx
  - 17:26
    
    X/Y multi-site reconstruction in dual-phase xenon detectors 14m
    
    In liquid xenon detectors searching for neutrinoless double beta decay (0vbb), single-site/multi-site (SS/MS) discrimination is critical for reducing backgrounds from 214Bi gamma rays. Dual-phase detectors, which utilize electroluminescence to measure the ionization signals, have demonstrated excellent multi-site identification in the longitudinal (z) direction but have not demonstrated SS/MS discrimination in the transverse (x/y) plane. If multi-site interactions could be identified down to separations of a few mm, 214Bi backgrounds could be reduced by a factor of two, potentially increasing the sensitivity of dual-phase detectors to 0vbb by up to ~50%. I will discuss the capability and limitations of x/y SS/MS discrimination in dual-phase detectors with the traditional electroluminescence readout, and introduce the possibility of adding additional wire grids to such detectors to improve spatial reconstruction via induction sensing.
    
    Speaker: Dr Brian Lenardo (SLAC)
    
    McGill 0vbb workshop - Nov 12, 2025 - X_Y multi-site reconstruction in dual-phase xenon detectors.pdf
  - 17:40
    
    A journey to ITACA 7m
    
    High-pressure gaseous xenon time projection chambers with electroluminescence (HGXeTPC-EL), are among the leading technologies for the search of neutrinoless double beta decay. Their combination of excellent energy resolution and detailed topological reconstruction enables powerful discrimination between single-electron and double-electron tracks, the latter representing the characteristic signature of a $0\nu\beta\beta$ event near the decay energy. Background suppression in these detectors relies critically on this topological information, but its effectiveness is ultimately limited by the diffusion of drifting electrons and by the spatial blurring introduced during electroluminescent amplification.
    
    Traditional approaches to mitigate diffusion, such as the addition of molecular cooling agents (e.g., CO$_2$, CH$_4$), are constrained by their strong quenching of xenon scintillation and electroluminescence. To overcome these limitations, we introduce ITACA (Ion Tracking with Ammonium Cations Apparatus), a novel concept that exploits both the prompt electron track and a delayed ion track to enhance event reconstruction. In this scheme, trace amounts of NH$_3$ (at ppb levels) convert xenon ions (Xe$^+$) into ammonium ions (NH$_4^+$) without affecting scintillation or EL yields. Electrons drift to the anode within milliseconds, forming the conventional EL image, while NH$_4^+$ ions drift slowly toward the cathode on a timescale of seconds. Using the primary scintillation (S1) signal as a timing reference, an electrostatic gate releases the ion cloud onto a sensor array of molecular detectors, which can be optically interrogated to reconstruct the ion track with sub-millimeter diffusion and without EL smearing.
    
    By combining the electron and ion images, ITACA could significantly improve the topological background rejection of xenon TPCs, potentially by an order of magnitude. The applicability of this technique to liquid xenon detectors is also discussed, though the higher density and reduced track length in the liquid phase make ion tracking less practical in that regime.
    
    Speaker: Dr Roberto Soleti
    
    itaca.pdf
- 19:00 → 21:30
  
  Workshop Dinner - Restaurant Hà - 600 Rue William 2h 30m Restaurant Hà
  
  Restaurant Hà
  
  600 Rue William Montréal, QC, H3C 1N6
Thursday, 13 November
- 08:30 → 09:00
  
  Pre-registration All zoom sessions: https://mcgill.zoom.us/my/xe0vbbws
  
  All zoom sessions: https://mcgill.zoom.us/my/xe0vbbws
- 09:00 → 10:00
  Lessons learned and plans for 0nbb: (Chair: Brian Mong)
  - 09:00
    
    Lessons learned from the formation of XLZD 20m
    
    Speaker: Dr Kim Palladino
    
    LessonsLearnedOnTheWaytoXLZD.pdf
  - 09:20
    
    Lessons learned from Global Argon Dark Matter 20m
    
    Speaker: Dr Jocelyn Monroe
  - 09:40
    
    Lessons learned from Dune and building in the current context 20m
    
    Speaker: Dr Mary Bishai
- 10:00 → 10:30
  
  Break - at the venue - light food and drink provided 30m
- 10:30 → 12:30
  Technical Challenges 2: (Chair: Jose Angel)
  - 10:30
    
    Photon detection systems 30m
    
    Speaker: Dr Fabrice Retière
    
    McGill0nbbLXeNov2025.pdf
  - 11:00
    
    Xenon storage and purification 30m
    
    Speaker: Dr Julien Masbou
    
    2025_11_13 Purification and Storage.pdf
  - 11:30
    
    Ba tagging 30m
    
    Speaker: Dr Pablo Herrero Gomez (Hebrew University)
    
    BaTa-NEXT-nEXO.pdf BaTa-NEXT-nEXO.pptx
  - 12:00
    
    Impact of microphysics and simulations 30m
    
    Speaker: Dr Eric Dahl (Northwestern University)
    
    Dahl -- Impact of microphysics and sims.pdf
- 12:30 → 14:00
  
  Lunch - provided 1h 30m
  
  at venue
- 14:00 → 15:30
  Technical Challenges 2: (Chair: Bill Fairbank)
  - 14:00
    
    Radon Control 30m
    
    Speaker: Dr Brian Mong (SLAC)
    
    251113 0vWorkshop Radon.pptx
  - 14:30
    
    Shielding/Water tank 30m
    
    Speaker: Dr Hugh Lippincott
    
    Shielding_Water Tank, Montreal 2025.pdf
  - 15:00
    
    Electronics & DAQ 30m
    
    Speaker: Dr Curro Toledo
    
    electronics.pdf
- 15:30 → 15:50
  
  Break - at the venue - light food and drink provided 20m
- 15:50 → 17:45
  Panel discussion on best strategy for Xenon experiments (Chair: Brian Lenardo)
  - 15:50
    
    Joint oversight committee talk 30m
    
    Speaker: Dr Nigel Smith
    
    2025-11-13 Xenon Workshop-1.pdf
  - 16:20
    
    Panel on best strategy for Xe experiments 1h 15m
    
    Moderator: Dr. Art McDonald
    Panelists:
    Dr. Jodi Cooley
    Dr. Juan José Gómez Cadenas
    Dr. Dan Akerib
    Dr. Krisha Kumar
    Dr. Sean Pauling
    
    Speakers: Dr Art McDonald - Moderator, Dr Dan Akerib, Dr Jodi Cooley, Juan José Gómez Cadenas, Krishna Kumar, Sean Pauling
- 17:45 → 19:45
  
  Les Restants d’Cabane at Thomson House 2h first floor (Thomson house)
  
  first floor
  
  Thomson house
  
  First floor
  
  Quebecois band - first floor of Thomson house. Hors d'oeuvres will be served
Friday, 14 November
- 08:30 → 09:00
  
  Preregistration 30m All zoom sessions: https://mcgill.zoom.us/my/xe0vbbws
  
  All zoom sessions: https://mcgill.zoom.us/my/xe0vbbws
- 09:00 → 10:30
  Xe detector technologies: (Chair: Dan Akerib)
  - 09:00
    
    Gas TPC 30m
    
    Speaker: Dr Justo Martin Albo
    
    20251114 | Montreal | Xe Gas TPCs.pdf
  - 09:30
    
    Liquid TPC 30m
    
    Speaker: Dr David Moore
    
    20251114_McGill_Xe.pdf
  - 10:00
    
    Dual Phase TPC 30m
    
    Speaker: Dr Kaixuan Ni
    
    DualPhase-TPC.pdf
- 10:30 → 11:00
  
  Break - at the venue - light food and drink provided 30m
  
  at venue
- 11:00 → 13:00
  Session 10: Where to go from here? (Chair: Stephen Sekula)
  - 11:00
    
    Other technologies 30m
    
    KamLAND2-ZEN, THEIA, LAR+Xe, and others
    
    Speaker: Dr Gabriel Orebi
    
    20251114 XeDBD.pdf
  - 11:30
    
    Quo Vadis 1h
    
    Where do we want to go? Can we develop a consortium? How would we do this?
    
    Speaker: Dr Ben Jones (UTA)
    
    0nubbXeTalk.pdf
  - 12:30
    
    Workshop summary and wrap-up 30m
    
    Speaker: Dr Thomas Brunner (McGill U)
    
    20251114-Xe-0vBB-end-red.pdf
- 13:00 → 14:00
  
  Lunch - provided 1h
  
  Lunch and end of workshop

Neutrinoless double beta decay search in Xe - next-generation experiment workshop

Thomson House Ballroom

Montreal

All zoom sessions: https://mcgill.zoom.us/my/xe0vbbws

Restaurant Hà

All zoom sessions: https://mcgill.zoom.us/my/xe0vbbws

first floor

Thomson house

All zoom sessions: https://mcgill.zoom.us/my/xe0vbbws