A5026924321- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Computational Physics and Python Applications
- Particle Accelerators and Free-Electron Lasers
- Astrophysics and Cosmic Phenomena
- Black Holes and Theoretical Physics
- Atomic and Subatomic Physics Research
- Cosmology and Gravitation Theories
- Particle accelerators and beam dynamics
- Particle Detector Development and Performance
- Superconducting Materials and Applications
- Distributed and Parallel Computing Systems
- Advanced X-ray Imaging Techniques
- Laser-Plasma Interactions and Diagnostics
- Radiation Detection and Scintillator Technologies
- Atomic and Molecular Physics
- Scientific Research and Discoveries
- Process Optimization and Integration
- Gyrotron and Vacuum Electronics Research
- Scientific Computing and Data Management
- Cold Atom Physics and Bose-Einstein Condensates
- Radiation Therapy and Dosimetry
Istituto Nazionale di Fisica Nucleare, Sezione di Padova
2011-2024
Korea Institute for Advanced Study
2024
University of Padua
2002-2020
Budker Institute of Nuclear Physics
2020
Novosibirsk State University
2020
Folkwang University of the Arts
2019
University of Siegen
2019
Istituto Nazionale di Fisica Nucleare
2012-2016
University of Bern
2002-2014
University of Zurich
2013
We review the present status of Standard Model calculation anomalous magnetic moment muon. This is performed in a perturbative expansion fine-structure constant $\alpha$ and broken down into pure QED, electroweak, hadronic contributions. The QED contribution by far largest has been evaluated up to including $\mathcal{O}(\alpha^5)$ with negligible numerical uncertainty. electroweak suppressed $(m_\mu/M_W)^2$ only shows at level seventh significant digit. It two loops known better than one...
Recently, it was shown that insertions of hadronic vacuum polarization at O(alpha^4) generate non-negligible effects in the calculation anomalous magnetic moment muon. This result raises question if other diagrams this order might become relevant for next round g-2 measurements as well. In note we show a potentially enhanced such contribution, light-by-light scattering combination with electron polarization, is already sufficiently suppressed.
The discrepancy between the Standard Model theory and experimental measurement of muon magnetic moment anomaly, ${a}_{\ensuremath{\mu}}=({g}_{\ensuremath{\mu}}\ensuremath{-}2)/2$, is connected to precision electroweak (EW) predictions via their common dependence on hadronic vacuum polarization effects. same data for total ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\text{hadrons}$ cross section, ${\ensuremath{\sigma}}_{\text{had}}(s)$, are used as input into dispersion relations...
We propose a new experiment to measure the running of electromagnetic coupling constant in space-like region by scattering high-energy muons on atomic electrons low-Z target through elastic process $$\mu \, e \rightarrow \mu e$$ . The differential cross section this process, measured as function squared momentum transfer $$t=q^2<0$$ , provides direct sensitivity leading-order hadronic contribution muon anomaly $$a^\mathrm{{HLO}}_{\mu }$$ By using beam 150 GeV, with an average rate $$\sim $$...
We update the constraints on two-Higgs-doublet models (2HDMs) focusing parameter space relevant to explain present muon g −2 anomaly, Δa μ , in four different types of models, type I, II, "lepton specific" (or X) and "flipped" Y). show that strong provided by electroweak precision data mass pseudoscalar Higgs, whose contribution may account for are evaded regions where charged scalar is degenerate with heavy neutral one mixing angles α β satisfy Standard Model limit − ≈ π/2. combine...
Contributions of a spin-0 axionlike particle (ALP) to lepton dipole moments, $g\ensuremath{-}2$ and EDMs are examined. Barr-Zee light-by-light loop effects from light pseudoscalar ALP found be capable resolving the longstanding muon discrepancy at expense relatively large $\mathrm{ALP}\text{\ensuremath{-}}\ensuremath{\gamma}\ensuremath{\gamma}$ couplings. The compatibility such couplings with direct experimental constraints perturbative unitarity bounds is discussed. Future tests scenario...
We propose a novel approach to determine the leading hadronic corrections muon g-2. It consists in measurement of effective electromagnetic coupling space-like region extracted from Bhabha scattering data. argue that this new method may become feasible at flavor factories, resulting an alternative determination potentially competitive with accuracy present results obtained dispersive via time-like
A bstract We argue that the anomalous magnetic moment of electron ( a e ) can be used to probe new physics. show present bound on new-physics contributions is 8 × 10 −13 , but sensitivity improved by about an order magnitude with measurements and more refined determinations α in atomic-physics experiments. Tests effects play crucial role interpretation observed discrepancy muon μ ). In large class models, moments scale square lepton masses thus anomaly suggests effect (0 . 7 ± 0 2) also...
This paper reviews and updates the standard model prediction of muon g-2. QED, electroweak hadronic contributions are presented, open questions discussed. The theoretical deviates from present experimental value by 2–3 deviations, if e+e− annihilation data used to evaluate leading term.
After a brief review of the muon $g\ensuremath{-}2$ status, we analyze possibility that present discrepancy between experiment and standard model (SM) prediction may be due to hypothetical errors in determination hadronic leading-order contribution latter. In particular, show how an increase hadroproduction cross section low-energy ${e}^{+}{e}^{\ensuremath{-}}$ collisions could bridge discrepancy, leading however decrease on electroweak upper bound ${M}_{H}$, SM Higgs boson mass. That is...
This article reviews and updates the Standard Model prediction of tau lepton g-2. Updated QED electroweak contributions are presented, together with new values leading-order hadronic term, based on recent low energy e+ e- data from BaBar, CMD-2, KLOE SND, light-by-light contribution. The total is confronted to available experimental bounds anomaly, prospects for its future measurements briefly discussed.
We evaluate the master integrals for two-loop, planar box-diagrams contributing to elastic scattering of muons and electrons at next-to-next-to leading-order in QED. adopt method differential equations Magnus exponential series determine a canonical set integrals, finally expressed as Taylor around four space-time dimensions, with coefficients written combination generalised polylogarithms. The electron is treated massless, while we retain full dependence on muon mass. considered are also...
Improved values for the two- and three-loop mass-dependent QED contributions to anomalous magnetic moments of electron, muon, $\ensuremath{\tau}$ lepton are presented. The standard model prediction electron ($g\ensuremath{-}2$) is compared with its most precise recent measurement, providing a value fine-structure constant in agreement recently published determination. For lepton, differences previously results found discussed.
A confirmation of the long-standing muon $g\ensuremath{-}2$ discrepancy requires both experimental and theoretical progress. On theory side, hadronic corrections are under close scrutiny, as they induce leading uncertainty Standard Model prediction. Recently, MUonE experiment has been proposed at CERN to provide a new determination contribution via measurement differential cross section muon-electron scattering. The precision expected this raises question whether possible physics (NP) could...
We propose a new method to probe the magnetic and electric dipole moments of $\tau$ lepton using precise measurements differential rates radiative leptonic decays at high-luminosity $B$ factories. Possible deviations these from Standard Model values are analyzed in an effective Lagrangian approach, thus providing model-independent results. Analytic expressions for relevant non-standard contributions decay presented. Earlier proposals examined. A detailed feasibility study our is performed...
The standard model prediction for muon-electron scattering beyond leading order requires the inclusion of QCD contributions which cannot be computed perturbatively. At next-to- and next-to-next-to-leading order, they arise from one- two-loop diagrams with hadronic vacuum polarization insertions in photon propagator. We present their evaluation using dispersive approach e^{+}e^{-} annihilation data estimate uncertainty. find that these corrections are crucial analysis future high-precision...
The recent measurement of the muon $g$-2 at Fermilab confirms previous Brookhaven result. leading hadronic vacuum polarization (HVP) contribution to represents a crucial ingredient establish if Standard Model prediction differs from experimental value. A lattice QCD result by BMW collaboration shows tension with low-energy $e^+e^- \to \text{hadrons}$ data which are currently used determine HVP contribution. We refer this as new puzzle. In Letter we consider possibility that physics...
We review the current status of theory predictions for elastic $\mu$-$e$ scattering, describing recent activities and future plans initiative related to proposed MUonE experiment.
Recent calculations have significantly decreased the scheme and residual scale dependence of basic radiative corrections Standard Electroweak Model. This leads to a theoretically accurate prediction W-boson mass MW, as well reduced upper bound for Higgs boson MH. The implications precise MW measurement on MH estimate are emphasized.
We present the differential rates and branching ratios of radiative decays $\tau \to l \bar{\nu} \nu \gamma$, with $l=e$ or $\mu$, $\mu e \gamma$ in Standard Model at next-to-leading order. Radiative corrections are computed taking into account full depencence on mass $m_l$ final charged leptons, which is necessary for correct determination ratios. Only partial agreement found previous calculations performed $m_l 0$ limit. Our results agree measurements $\mathcal{B} (\mu \gamma)$ (\tau \mu a...
We discuss radiative corrections to $W$ and quark propagators in the resonance region $|s\ensuremath{-}{M}^{2}|\ensuremath{\lesssim}M\ensuremath{\Gamma}.$ show that conventional mass renormalization, when applied photonic or gluonic corrections, leads next leading order (NLO) contributions proportional $[M\ensuremath{\Gamma}/(s\ensuremath{-}{M}^{2}){]}^{n},$ $(n=1,2,\dots{}),$ i.e., a non-convergent series region, difficulty affects all unstable particles coupled massless quanta. A solution...