"X17 What if?" Workshop

19 Mar 2026, 09:00 → 20 Mar 2026, 16:00 Europe/Rome

Aula Salvini (LNF - Building 36)

Antonio De Santis (Istituto Nazionale di Fisica Nucleare), Elisa Di Meco (Istituto Nazionale di Fisica Nucleare), Fabio Bossi (Istituto Nazionale di Fisica Nucleare), Marco Mancini (Istituto Nazionale di Fisica Nucleare)

The recent result published by the PADME Collaboration at LNF, has strengthened the interest in the searches for the hypothetical X17 particle, whose existence has been firstly suggested by nuclear physics experiments performed at ATOMKI. 

The aim of the Workshop is to provide a comprehensive review of the current experimental activities, and of the possible future developments in this field. Emphasis will be given to searches at particle's accelerators.

 

 

ZOOM link for remote participation:

https://infn-it.zoom.us/j/84119745524?pwd=taEw29br7SUvzwEXaxOvGsb4XQ9wec.1

Privacy_Policy_EN.pdf

Safety_Rules_EN.pdf

WiFi SSID INFN instructions_X17.pdf

X_17_2026.pdf

Thursday 19 March

Registration

Registration and coffee

Morning Session

1 Welcome

Speaker: Dr Paola Gianotti (LNF)

2 Theoretical overview

Speakers: Dr Claudio Toni (LAPTh, CNRS), Claudio Toni (Istituto Nazionale di Fisica Nucleare), Claudio Toni (Sapienza), Claudio Toni (LAPTh, CNRS)

X17_frascati.pdf

3 News from ATOMKI

Speaker: Prof. Attila Krasznahorkay (Inst. of Nucl. Res. of the Hung. Acad. of Sci. (ATOMKI), Head, Division of Nuclear Physics)

X17-Krasznahorkay-Frascati.pdf

4 The X17 Search at PADME: From Run III results to Run IV upgrades

Speaker: Mr Marco Mancini (Istituto Nazionale di Fisica Nucleare)

X17WhatIf_PADME_MM.pdf

5 PADME future and perspects

Speaker: Paolo Valente (Istituto Nazionale di Fisica Nucleare)

padme-what-if-valente-19mar2026.pdf

6 X17 searches at the BESIII

Speaker: Hang Zhou (Helmholtz Institute Mainz)

X17_LNF_HZhou_v3.pdf

Break: Lunch Break

Afternoon Session

7 An Overview of the Upcoming X17 Experiment at Jefferson Lab

Speaker: Huong Nguyen (University of Virginia)

HuongNguyen_X17_Frascati_2026March20_v2.pdf

8 Study of the Anomalous Internal Pair Creation in 8Be at LNL-INFN

Speaker: Benito Gongora Servin (Istituto Nazionale di Fisica Nucleare)

X17_WhatIf_Gongora.pdf

X17_WhatIf_Gongora.pptx

9 Status of the DarkLight Experiment

Remote talk

Speaker: Ethan Cline (MIT)

DarkLight_Status.pdf

Break: Coffe Break

Afternoon Session

10 Searching for MeV-scale particles with TeV-scale beams

Speaker: Andre Sterenberg Frankenthal (UC Irvine)

Frankenthal_X17_WhatIf_ATLAS_CMS_low_mass_physics.pdf

11 Search for feebly interacting particles at LHCb: status and prospects

Speaker: Gaia Lanfranchi (Istituto Nazionale di Fisica Nucleare)

WhatIf_Gaia_Lanfranchi.pdf

12 Dark sector searches at Belle II

Speaker: Enrico Graziani (Istituto Nazionale di Fisica Nucleare)

graziani-X17-whatif.pdf

Event: Welcome Party

Friday 20 March

Morning Session

13 Dark sector searches at Jefferson Lab

Speaker: Mariangela Bondi (Istituto Nazionale di Fisica Nucleare)

Bondi_WS_X17.pdf

14 MEG II

Speaker: Cecilia Voena (Istituto Nazionale di Fisica Nucleare)

Voena_X17WhatIf.pdf

15 X17 Searches at the MAGIX Spectrometer Setup at MESA

Speaker: Dr Sebastian Stengel (JGU Mainz)

X17SearchesAtTheMAGIXSpectrometerSetupAtMESA.pdf

X17SearchesAtTheMAGIXSpectrometerSetupAtMESA_v2.pdf

Break: Coffe Break

Morning Session

16 Searching for Light Dark Matter with the DarkMESA beam dump experiment

Speakers: Patrick Achenbach (Mainz University), Patrick Achenbach (Jefferson Lab), Patrick Achenbach (Nuclear Physics Institute, Gutenberg-University, Mainz)

Achenbach-X17Workshop-Frascati-2026.pdf

17 Searching the X17 in the NA64 experiment at CERN

Speaker: Prof. Andrea Celentano (Istituto Nazionale di Fisica Nucleare)

2026_03_20_X17LNF-2.pdf

18 Closing remarks

Speakers: Venelin Kozhuharov (Faculty od Physics, Sofia - Istituto Nazionale di Fisica Nucleare), Venelin Kozhuharov (Faculty of Physics, Sofia University "St. Kl. Ohridski" & LNF-INFN)

2026-03-20-X17_WhatIf-3.pdf

Break: Lunch Break

Event: Visit to the Laboratory