The Low-Energy Frontier of Particle Physics

10 Feb 2025, 08:30 → 12 Feb 2025, 18:00 Europe/Rome

Aula Salvini (INFN-LNF)

Despite its great success, the Standard Model of particle physics has significant limitations. It does not account for the observed imbalance between matter and antimatter in the Universe, it cannot explain the nature of dark matter and dark energy, and it fails to incorporate gravity. Many extensions of the Standard Model, including models of dark matter, predict the existence of new particles with sub-MeV masses, interacting very weakly with ordinary matter. These particles could manifest through violations of discrete or Lorentz symmetries, temporal variations in fundamental constants, new forces, or as candidates for dark matter and dark energy. Precision experiments at low-energy and medium-scale facilities hold the potential to detect these phenomena. This workshop aims to foster collaborative approaches to low-energy tests of new physics in microwave, optical, atomic, nuclear, and condensed matter systems.

Kindly proceed to the videoconference session (on the left menu) to join the conference via Zoom.

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Monday, 10 February

1 The Low Energy Frontier of Particle Physics

We will discuss a few hand-picked examples of how “table-top” experiments push the frontiers of particle physics and may help us answer the “big” (a.k.a., elephant-in-the room) questions.

Speaker: DMITRY BUDKER (Helmholtz Institute Mainz)

Budker_Low-energy_frontier_Frascati_2025.pptx

Gravity and Quantum Mechanics

Convener: Claudio Gatti (Istituto Nazionale di Fisica Nucleare)

2 Quantum effects in gravity from a delocalised quantum source

Understanding the fundamental nature of gravity at the interface with quantum theory is a major open question in theoretical physics. Recently, the study of gravitating quantum systems, for instance a massive quantum system prepared in a quantum superposition of positions and sourcing a gravitational field, has attracted a lot of attention: quantum optics experiments are working towards realising such a scenario in the laboratory, and measuring the gravitational field associated to a quantum source is expected to give some information about the nature of gravity. On the theory side, quantum information tools are used to interpret the results. However, there are still open questions concerning the precise conclusions that these experiments could draw on the quantum nature of gravity, such as whether experiments in this regime will be able to test more than the Newtonian part of the gravitational field.
In my talk, I will present a new result, where a delocalised quantum source gives rise to effects that cannot be reproduced using the Newton potential nor as a limit of classical General Relativity. These effects can in principle be measured by performing an interference experiment, and are independent of graviton emission.
Identifying stronger quantum aspects of gravity than those reproducible with the Newton potential is crucial to prove the nonclassicality of the gravitational field and to plan a new generation of experiments testing quantum aspects of gravity in a broader sense than what proposed so far.

Speaker: Flaminia Giacomini (ETH Zürich)

Giacomini_Frascati.pdf

3 The Archimedes Experiment: a way for exploring the Vacuum-Gravity Interaction

The Archimedes experiment has the goal to measure the vacuum fluctuations interaction with Gravity. A high sensitive balance is employed to measure the small weight variations of high Tc superconducting samples when they pass to their superconductive status.
We descrive the challenging experimental solutions adopted for having a very efficient heat exchange with the samples only through the radiation mechanism and we present the first promising results to reach the goal of this experiment.

Speaker: Dr Paola Puppo (INFN - ROMA)

LNF2025 - Archimedes_Puppo_v2.pdf

16:30 Coffee Break

4 Atom interferometry for fundamental physics tests

Today, matter-wave interferometers such as clocks and gravimeters allow precision measurements of time and gravity at unprecedented levels. In all these sensors, the exquisite control of both internal (electronic) and external (center of mass motion) degrees of freedom of ultra-cold atomic samples, enable us to study interactions at their most basic, quantum level, paving the way for new tests of fundamental physics.

In this talk, I’ll review the most recent results in the field and discuss the prospects of novel atom interferometry schemes based on ultra-narrow, intercombination transitions of alkali-earth-like atoms.

Speaker: Nicola Poli (Istituto Nazionale di Fisica Nucleare)

FrascatiPoli2025_finale.pdf

FrascatiPoli2025_finale.pptx

5 Opening the direct search of ultralight B-L dark photon in the 10-16 eV region with the Archimedes balance

In recent years, astrophysical dark matter research is rapidly expanding towards ultralight bosons and new detection techniques are appearing on the horizon. Among these, the detection of small forces at frequency f = mA c^2/h (mA is the mass of the boson) on mechanical systems, a path opened by the Gravitational Wave detectors Virgo and LIGO, particularly in the mass region 10-14 to 10-11 eV. In the case of smaller masses, torsion pendulums or specially sized balances are promising detectors. In our case, a prototype balance built for the Archimedes experiment reached a limit on the coupling constant not far from the limits set by indirect measurements (MICROSCOPE), so that a better apparatus, actually the Archimedes balance currently under construction, embodies a concrete possibility to extend the direct search for the B-L dark photon beyond the region explorable with Gravitational Wave detectors.

Speaker: Enrico Calloni (Istituto Nazionale di Fisica Nucleare)

Calloni_DarkPhoton_Frascati_2025.pdf

Calloni_DarkPhoton_Frascati_2025.ppt

6 Experiments on gravity with opto-mechanical resonators

I will describe two INFN experiments exploiting opto-mechanical resonators for investigating involving gravity. The first is HUMOR, which set upper limits to possible deformation of the standard commutator between position and momentum. The second is GRAFIQO, aiming to detect gravitational interaction between low-mass oscillators.

Speaker: Francesco Marin (INFN Firenze)

Tuesday, 11 February

Symmetry Violation

Conveners: Bernard Van Heck (Sapienza), Giovanni Grilli di Cortona (Istituto Nazionale di Fisica Nucleare)

7 Axions and ALPs Beyond Discovery

Speaker: Joerg Jaeckel (ITP Heidelberg)

Frascati2.pdf

8 Testing The Pauli Exclusion Principle and fundamental symmetries in underground laboratories: the VIP-2 experiment

The Pauli Exclusion Principle (PEP) is one of the main
cornerstones of the Quantum Theory. Violation of the PEP, albeit small, could be
motivated by physics beyond the Standard Model which entail extra space
dimensions, violation of the Lorentz invariance, non-commutative space-time.
These scenarios can be experimentally constrained with stat-of-the-art X-ray
spectroscopy, searching for forbidden transition in atomic systems. I shall present
the latest results of the VIP-2, and the impact on Quantum gravity models and fundamental symmetries.

Speaker: Fabrizio Napolitano (Istituto Nazionale di Fisica Nucleare)

Low Energy Frontier 25 Napolitano.pdf

10:50 Coffee break

9 Probing the electron's EDM using cold and slow molecules

Precision measurements on molecular quantum systems have developed into a powerful way to explore new physics. Such measurements are currently the most sensitive way to probe an effective asymmetry in the charge distribution of the electron - its electric dipole moment. Through a measurement of this property, limits can be set on possible extensions of the Standard model of particle physics. In this talk we will present the context, methods and latest developments in this field where the precision techniques of atomic and molecular physics are used to probe the frontiers of particle physics. A particular focus is put on our work to produce slow beams and trapped samples of suitable molecules.

Speaker: Steven Hoekstra (University of Groningen)

Frascati 11 feb 2025 Hoekstra v2.pdf

10 A Theoretical Overview of EDMs

Speaker: Luca Di Luzio (Istituto Nazionale di Fisica Nucleare)

Di Luzio_LNF2025.pdf

11 Discussion on Symmetry Violations

Speaker: Antonio Masiero (Istituto Nazionale di Fisica Nucleare)

LNF_material for the discussion session_11-02-25.pdf

13:30 Lunch at LNF canteen

Light Dark Matter

Conveners: Mauro Valli (Istituto Nazionale di Fisica Nucleare), Angelo Esposito (Sapienza)

12 Fundamental physics with levitated micromagnets

Macroscopic and mesoscopic ferromagnets levitated by Meissner effect in vacuum behave as multimode mechanical systems with ultrahigh quality factor and high sensitivity to external magnetic fields. Furthermore, they can be easily coupled to superconducting quantum devices. This suggests the possibility of using this experimental platform for a variety of measurements in the context of fundamental and quantum physics. In this talk I will review our recent experimental work on levitated micromagnets with SQUID-based detection. Among various results, we have recently demonstrated magnetic field resolution beyond the energy resolution limit, atomic-like gyroscopic effects, and ultrafast spinning at MHz frequencies. I will discuss potential applications to fundamental physics, including the search for ultralight dark matter, fifth force measurements, and more speculative investigations on the macroscopic limits of quantum mechanics.

Speaker: Andrea Vinante (Istituto Nazionale di Fisica Nucleare)

Vinante - Frascati2025.pdf

13 Atoms as electron accelerators

Resonant positron annihilation on atomic electrons is a powerful technique for searching for light new particles that couple to $e^+e^-$. Precise estimates of production rates require a detailed characterisation of atomic electron momentum distributions. I will present a general method that leverages the Compton profile of the target material to accurately account for electron velocity effects in resonant annihilation cross-sections. Additionally, I will discuss the implications of this precise computation for new physics searches and explore how high Z atoms can effectively serve as electron accelerators, significantly extending the experimental mass reach. Finally, I will demonstrate that by harnessing the relativistic velocities of electrons in the inner atomic shells, a high-intensity 12 GeV positron beam — such as the one planned at JLab — can enable precise measurements of the hadronic cross section, from the two-pion threshold to a center-of-mass energy exceeding 1 GeV.

Speaker: Giovanni Grilli di Cortona (Lngs)

Grilli_LNF.pdf

14 Searching for Light Dark Matter with Carbon Nanotubes: the ANDROMeDa Project

Since the discovery of carbon nanotubes in 1991 there has been widespread excitement for their unique chemical, electrical and mechanical properties. The introduction of carbon nanotubes has led to technological breakthroughs in many fields, including electronics, biotechnologies, and chemical sensors. The aim of ANDROMeDa (Aligned Nanotube Detector for Research On MeV Darkmatter) is to introduce carbon nanotubes to the field of particle detectors, by developing a novel dark matter detector: the Dark-PMT.

Speaker: Francesco Pandolfi (INFN Rome)

pandolfi_ANDROMeDa_2025_02_11.pdf

16:30 Coffee Break

15 New frontiers in sub-MeV dark matter searches

Speaker: Angelo Esposito (Istituto Nazionale di Fisica Nucleare)

LNF Esposito.pdf

16 DELight: The Direct Search Experiment for Light Dark Matter

There is vast parameter space to explore for dark matter masses below a few GeV, and the field of direct dark matter detection is constantly expanding to new frontiers. In particular, low mass dark matter candidates necessitate novel detector designs with lower thresholds and alternative target materials compared to e.g. the xenon-based experiments currently providing the strongest overall constraints on many dark matter models. The Direct search Experiment for Light dark matter (DELight) will deploy a target of superfluid 4He instrumented with large area microcalorimeters (LAMCALs) based on magnetic microcalorimeter (MMC) technology in a setup optimized for low mass dark matter searches. In this talk the motivation, setup, and current status of this novel upcoming experiment will be presented.

Speaker: Eleanor Katherine Fascione

INFN_LEFPP_Feb2025_Fascione.pdf

17 Axion Experiments

Speaker: Giovanni Carugno (Istituto Nazionale di Fisica Nucleare)

LNF-INFN-Frascati-25.pdf

18 Discussion on Light Dark Matter

Speaker: Angelo Esposito (Sapienza)

Wednesday, 12 February

Fifth Force and Variation of Fundamental Constants

Convener: Angelo Esposito (Sapienza)

19 Overview of 229mTh based nuclear clock

Nuclear transitions have energy scale a few orders of magnitude larger than atomic ones. This mismatch of energy scales prevented to use laser sources for excitation of nuclear levels. In the 70th it was deduced that 229Th isotope might have an isomeric state at the energy of a few eVs. Recently, with development of the optical frequency combs, this state stimulated a broad interest, in particular regarding a possible nuclear clock application, allowing to enhance the atomic clock precision and test correlations between fundamental forces. In the last decade many experiments on the 229mTh isomer were performed, including TORIO-229 experiment of INFN, confirming the past expectations. In this presentation an overview of the current knowledge on the lowest nuclear isomer 229mTh will be presented as well as its possible future applications.

Speaker: Dr Mikhail Osipenko (GE)

lowen24_osipenko.pdf

20 Frequency metrology of buffer-gas-cooled molecular spectra for fundamental Physics research

Based on the production of molecular samples at cryogenic temperatures by the buffer-gas-cooling technique and their combination with cavity-enhanced spectroscopy in the Lamb-dip regime, we present a new generation of high-accuracy physics tests beyond the Standard Model at the eV energy scale. Examples include searching for putative fifth-force interactions and assessing the space-time stability of the proton-to-electron mass ratio.

Speaker: Pasquale Maddaloni (Istituto Nazionale di Fisica Nucleare)

Mad_frascati_6.pdf

10:50 Coffee Break

21 Long range forces: A theory review

Various types of BSM physics, in particular new light particles, can lead to long-range forces. We can search for such "fifth force" interactions by sensitivity measuring gravity on various scales. In this talk, I will review how such long-range forces can be generated and how they lead to apparent violations of the inverse-square law and the equivalence principle of gravity. I will also discuss the of different types of long-range forces and give an overview of which kinds of BSM physics that long-range forces can be used to test.

Speaker: Philip Soerensen (Istituto Nazionale di Fisica Nucleare)

long_range_force_theory_review.pdf

22 Discussion on 5th force and variation of fundamental constants

Speakers: Philip Soerensen (Istituto Nazionale di Fisica Nucleare), Angelo Esposito (Sapienza)

Round Table: “Training School on Low Energy Frontier of Particle Physics”

Conveners: Angelo Esposito (Sapienza), Claudio Gatti (Istituto Nazionale di Fisica Nucleare), Marco Nardecchia (Istituto Nazionale di Fisica Nucleare), Marco Vignati (Istituto Nazionale di Fisica Nucleare)

13:30 Lunch at LNF canteen