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Graziano Venanzoni

Publications and source records attributed to Graziano Venanzoni.

At least 19 recordsLinked to original sources
arXiv2026

Continuous coherent spin-frequency metrology in storage rings via resonant beam-driven detection

Precision measurements in storage rings are increasingly limited by the ability to monitor collective spin dynamics coherently over long time scales. Existing polarimetry techniques rely on destructive scattering processes that preclude continuous, non-intercepting tracking of spin evolution and constrain both statistical sensitivity and systematic control. Here we introduce a non-destructive, phase-coherent polarimetry method in which the stored beam polarization is treated as a continuous dynamical observable rather than a quantity inferred from scattering events. Spin-dependent electromagnetic fields generated by a polarized relativistic beam establish a symmetry-selected differential signal on pickup electrodes. This signal is transduced into a narrowband phase modulation of a high-Q resonator interrogated with a coherent probe, while dominant charge-induced backgrounds are rejected through geometric symmetry, helicity reversal, and synchronous demodulation. Controlled spin precession (spin-wheel operation) provides a stable phase reference enabling phase-coherent detection of slow spin evolution. Combined with optimized lattice symmetry and beam cooling, this approach can substantially extend the usable spin coherence time, with values approaching 10^5 s appearing realistic within existing accelerator technology. The resulting readout supports optimal slope-based estimation with T^{-3/2} statistical scaling while eliminating the efficiency penalties inherent to scattering-based polarimetry. For storage-ring EDM experiments, this combination enables sensitivity approaching the level expected within the Standard Model. More broadly, the method establishes a general phase-coherent architecture for collective spin measurements in storage rings, adapting resonant sensing concepts from axion dark-matter searches to charged-particle precision experiments.

hep-ex↗
arXiv2026

PrecisionSM: an annotated database for low-energy $e^+e^-$ hadronic cross sections

PrecisionSM is an annotated database that compiles the available data on low-energy cross sections of electron-positron collisions into hadronic channels. This database organizes and collects data samples from $e^+e^-$ experiments, which are used as input for the data-driven theoretical evaluation of the muon anomalous magnetic moment, $a_μ$, serving as a precise test of the Standard Model when compared to the experimental measurements of $a_μ$. The database is accessible through a custom website (https://precision-sm.github.io) which contains details about the data samples, such as the treatment of radiative corrections, as well as links to papers on INSPIRE-HEP and to tables on HEPData. The PrecisionSM database was developed within a Joint Research Initiative in the group application of the European hadron physics community, STRONG2020, and is now incorporated into the RadioMonteCarLow2 Working Group (RMCL2 WG) activities, which have the more general goal of improving the theoretical description of scattering processes at $e^+e^-$ colliders. The results of Phase I of the new RMCL2 WG have been published in Aliberti et al, arXiv:hep-ph/2410.22882. In this proceeding, we will report on the status of the PrecisionSM database, which currently contains a list of the dominant $2π$ channel as well as $3π$ and $π^0γ$, and on the ongoing work for the other channels and for responsive plots.

hep-ph↗
arXiv2026

Measured Lepton Magnetic Moments

The electron and muon magnetic moments have played, and continue to play, important roles in testing the fundamental mathematical description of physical reality called the Standard Model of particle physics (SM). The electron magnetic moment is the most precisely measured property of an elementary particle and the most precise SM prediction, setting up the most precise confrontation ever between experiment and theory. It enables the most precise test of quantum field theory, and of the fundamental CPT symmetry invariance of the SM with leptons. The stable electron is studied with quantum methods while the electron remains for months in its quantum ground and first excited states. The muon magnetic moment is one of the most precisely measured property of an unstable elementary particle. Although less precise measured than the electron, it provides greater sensitivity to physics beyond the Standard Model -- a powerful tool for testing the existence of new particles and forces. Because muons decay quickly, they must be studied as they orbit at nearly the speed of light in a large storage ring. The extremely high precision of the electron and muon magnetic moment measurements has driven major advances in theoretical physics, inspiring new techniques in quantum field theory, precision calculations, and lattice gauge theory. Only experimental limits currently exist on the size of the magnetic moments of the tau and neutrino leptons.

hep-ex↗
arXiv2025

Status of the Muon g-2/EDM Experiment at J-PARC

The Muon g-2/EDM Experiment at J-PARC will employ a novel way to measure the muon magnetic anomaly, a_mu = (g-2)_mu/2, by using a low-emittance beam of positive muons stored in a compact muon storage magnet. The experimental method includes new technologies such as a three-dimensional spiral injection, an MRI-type storage magnet with superb field uniformity, and a positron tracking detector. The expected systematic uncertainty will be at the same level as that of the Fermilab Muon g-2 experiment, providing an important cross-check of the "storage-ring method" employed at BNL and Fermilab. I will present the current status of the experiment, ongoing tests and design optimizations, and the plans for improvements of the experimental precision.

hep-ex↗
arXiv2025

Radiative corrections and Monte Carlo tools for low-energy hadronic cross sections in $e^+ e^-$ collisions

We present the results of Phase I of an ongoing review of Monte Carlo tools relevant for low-energy hadronic cross sections. This includes a detailed comparison of Monte Carlo codes for electron-positron scattering into a muon pair, pion pair, and electron pair, for scan and radiative-return experiments. After discussing the various approaches that are used and effects that are included, we show differential cross sections obtained with AfkQed, BabaYaga@NLO, KKMC, MCGPJ, McMule, Phokhara, and Sherpa, for scenarios that are inspired by experiments providing input for the dispersive evaluation of the hadronic vacuum polarisation.

hep-ph↗
arXiv2025

Status of the Proton EDM Experiment (pEDM)

The Proton EDM Experiment (pEDM) is the first direct search for the proton electric dipole moment (EDM) with the aim of being the first experiment to probe the Standard Model (SM) prediction of any particle EDM. Phase-I of pEDM will achieve $10^{-29} e\cdot$cm, improving current indirect limits by four orders of magnitude. This will establish a new standard of precision in nucleon EDM searches and offer a unique sensitivity to better understand the Strong CP problem. The experiment is ideally positioned to explore physics beyond the Standard Model (BSM), with sensitivity to axionic dark matter via the signal of an oscillating proton EDM and across a wide mass range of BSM models from $\mathcal{O}(1\text{GeV})$ to $\mathcal{O}(10^3\text{TeV})$. Utilizing the frozen-spin technique in a highly symmetric storage ring that leverages existing infrastructure at Brookhaven National Laboratory (BNL), pEDM builds upon the technological foundation and experimental expertise of the highly successful Muon $g$$-$$2$ Experiments. With significant R\&D and prototyping already underway, pEDM is preparing a conceptual design report (CDR) to offer a cost-effective, high-impact path to discovering new sources of CP violation and advancing our understanding of fundamental physics. It will play a vital role in complementing the physics goals of the next-generation collider while simultaneously contributing to sustaining particle physics research and training early-career researchers during gaps between major collider operations.

hep-ex↗
arXiv2023

An alternative evaluation of the leading-order hadronic contribution to the muon g-2 with MUonE

We propose an alternative method to extract the leading-order hadronic contribution to the muon g-2, $a_μ^\text{HLO}$, with the MUonE experiment. In contrast to the traditional method based on the integral of the hadronic contribution to the running of the effective fine-structure constant $Δα_{had}$ in the space-like region, our approach relies on the computation of the derivatives of $Δα_{had}(t)$ at zero squared momentum transfer $t$. We show that this approach allows to extract $\sim 99\%$ of the total value of $a_μ^\text{HLO}$ from the MUonE data, while the remaining $\sim 1\%$ can be computed combining perturbative QCD and data on $e^+e^-$ annihilation to hadrons. This leads to a competitive evaluation of $a_μ^\text{HLO}$ which is robust against the parameterization used to model $Δα_{had}(t)$ in the MUonE kinematic region, thanks to the analyticity properties of $Δα_{had}(t)$, which can be expanded as a polynomial at $t\sim 0$.

hep-ph↗
arXiv2023

New results from the Muon g-2 Experiment

The Muon g-2 experiment at Fermilab has published the first result on Run-1 dataset in 2021 showing a good agreement with the previous experimental result at Brookhaven National Laboratory at comparable precision (0.46 ppm). In August 2023 we released our new result from Run-2 and Run-3 datasets which allowed to measure $a_μ$ to 0.21 ppm, a more than two-fold improved precision respect to Run-1, and which allowed to reach a precision of 0.20 ppm when combined with the Run-1 result. We will discuss the improvements of the Run-2/3 analysis respect to Run-1, the current status of the theory prediction, and the future prospects.

hep-ex↗
arXiv2023

Towards a full NNLO Monte Carlo generator for low energy $e^+e^-$ data into leptons and hadrons

During the last 15 years the Radio MonteCarLow Working Group has been providing valuable support to the development of radiative corrections and Monte Carlo event generators for low energy $e^+e^-$ data and $τ$-lepton decays. While the working group has been operating for more than 15 years without a formal basis for funding, parts of our program have recently been included as a Joint Research Initiative in the group application of the European hadron physics community, STRONG2020, to the European Union, with a more specific goal of creating an annotated database for low-energy hadronic cross sections in $e^+e^-$ collisions. In parallel the theory community is continuing its effort towards the realization of improved Monte Carlo generators with for low energy $e^+e^-$ data into hadrons. Full NNLO corrections in the leptonic sector are to be combined with an improved treatment of radiative corrections involving pions. This is of relevance for the precise determination of the leading hadronic contribution to the muon g-2. We will report on these initiatives.

hep-ph↗
arXiv2022

The storage ring proton EDM experiment

We describe a proposal to search for an intrinsic electric dipole moment (EDM) of the proton with a sensitivity of \targetsens, based on the vertical rotation of the polarization of a stored proton beam. The New Physics reach is of order $10^~3$TeV mass scale. Observation of the proton EDM provides the best probe of CP-violation in the Higgs sector, at a level of sensitivity that may be inaccessible to electron-EDM experiments. The improvement in the sensitivity to $θ_{QCD}$, a parameter crucial in axion and axion dark matter physics, is about three orders of magnitude.

hep-ph↗
arXiv2021

A study of muon-electron elastic scattering in a test beam

In 2018, a test run with muons in the North Area at CERN was performed, running parasitically downstream of the COMPASS spectrometer. The aim of the test was to investigate the elastic interactions of muons on atomic electrons, in an experimental configuration similar to the one proposed by the project MUonE, which plans to perform a very precise measurement of the differential cross-section of the elastic interactions. COMPASS was taking data with a 190 GeV pion beam, stopped in a tungsten beam dump: the muons from these pions decays passed through a setup including a graphite target followed by 10 planes of Si tracker and a BGO crystal electromagnetic calorimeter placed at the end of the tracker. The elastic scattering events were analysed, and compared to expectations from MonteCarlo simulation.

hep-ex↗
arXiv2019

Status of the MUonE experimental proposal

We present the status of the MUonE experimental proposal which aims at determining the leading order hadronic contribution to the muon g-2 by measuring the hadronic part of the photon vacuum polarization in the space-like region.

hep-ex↗
arXiv2017

From Hadronic Cross Section to the measurement of the Vacuum Polarization at KLOE: a fascinating endeavour

The KLOE experiment at the $ϕ-factory$ DA$Φ$NE in Frascati is the first to have employed Initial State Radiation (ISR) to precisely determine the $e^+e^-\toπ^+π^-(γ)$ cross section below 1 GeV. Such a measurement is particularly important to test the Standard Model (SM) calculation for the $(g-2)$ of the muon, where a long standing 3$σ$ discrepancy is observed. I will review the ISR activity in KLOE in the last 18 years from the measurement of the hadronic cross section to the first direct determination of the time-like complex running $α(s)$ in the region below 1 GeV.

hep-ex↗
arXiv2016

Measuring gravitational effects on antimatter in space

We propose an experimental test of the gravitational interaction with antimatter by measuring the branching fraction of the CP~violating decay $K_\mathrm{L} \to π^{+} π^{-}$ in space. We show that at the altitude of the International Space Station, gravitational effects may change the level of CP~violation such that a 5$σ$ discrimination may be obtained by collecting the $K_\mathrm{L}$ produced by the cosmic proton flux within a few years.

hep-ph↗
arXiv2014

The New Muon g-2 experiment at Fermilab

There is a long standing discrepancy between the Standard Model prediction for the muon g-2 and the value measured by the Brookhaven E821 Experiment. At present the discrepancy stands at about three standard deviations, with a comparable accuracy between experiment and theory. Two new proposals -- at Fermilab and J-PARC -- plan to improve the experimental uncertainty by a factor of 4, and it is expected that there will be a significant reduction in the uncertainty of the Standard Model prediction. I will review the status of the planned experiment at Fermilab, E989, which will analyse 21 times more muons than the BNL experiment and discuss how the systematic uncertainty will be reduced by a factor of 3 such that a precision of 0.14 ppm can be achieved.

physics.ins-det↗
arXiv2013

The Muon (g-2) Theory Value: Present and Future

This White Paper briefly reviews the present status of the muon (g-2) Standard-Model prediction. This value results in a 3 - 4 standard-deviation difference with the experimental result from Brookhaven E821. The present experimental uncertainty is $\pm 63 \times 10^{-11}$ (0.54~ppm), and the Standard-Model uncertainty is $\simeq \pm 49 \times 10^{-11}$. Fermilab experiment E989 has the goal to reduce the experimental error to $\pm 16 \times 10^{-11}$. Improvements in the Standard-Model value, which should be achieved between now and when the first results from Fermilab E989 could be available, should lead to a Standard-Model uncertainty of $\sim \,\pm 35 \times 10^{-11}$. These improvements would halve the uncertainty on the difference between experiment and theory, and should clarify whether the current difference points toward New Physics, or to a statistical fluctuation. At present, the (g-2) result is arguably the most compelling indicator of physics beyond the Standard Model and, at the very least, it represents a major constraint for speculative new theories such as supersymmetry, dark gauge bosons or extra dimensions.

hep-ph↗
arXiv2009

A precise new KLOE measurement of $|F_π|^2$ with ISR events and determination of $ππ$ contribution to $a_μ$ for $0.592 < M_{ππ} < 0.975$ GeV

The KLOE experiment at the DA$Φ$NE $ϕ$-factory has performed a new precise measurement of the pion form factor using Initial State Radiation events, with photons emitted at small polar angle. Results based on an integrated luminosity of 240 pb$^{-1}$ and extraction of the $ππ$ contribution to $a_μ$ in the mass range $0.35< M^2_{ππ}<0.95$ GeV$^2$ are presented. The new value of $a^{ππ}_μ$ has smaller (30%) statistical and systematic error and is consistent with the KLOE published value (confirming the current disagreement between the standard model prediction for $a_μ$ and the measured value).

hep-ex↗