Conveners
Poster Session
- Wolfgang Gradl
The anomalous magnetic moment of the muon $a_\mu=(g_\mu-2)/2$ is one of the most precisely measured quantities in modern physics. However, there is a sizable discrepancy between the Standard Model (SM) prediction of the Muon $g-2$ Theory Initiative and the experimental average of the latest direct measurements at BNL and FNAL. This discrepancy is known as the Muon $g-2$ puzzle. For the SM...
The hadronic vacuum polarization is an important contribution to the running QED coupling constant at the $Z$ pole, $\alpha_\mathrm{QED}(M_Z^2)$, and the anomalous magnetic moment of the muon $a_\mu = (g_\mu - 2) / 2$. Both quantities allow for precision tests of the Standard Model (SM). Their theoretical uncertainties are dominated by hadronic contributions. Experimental inputs, like the...
The 10 billion J/\psi decays collected with the BESIII experiment offer a unique opportunity to investigate the decays of \eta and \eta^\prime mesons produced in the radiative and hadronic J/\psi \to \gamma \eta^{(\prime)}, \phi \eta^{(\prime)} transitions. Using this clean production mechanism, the BESIII experiment is making important contributions to
precision studies of the strong and...
Coherent pion photoproduction on nuclei is an efficient tool for studying nucleon density and determining neutron skin thickness. However, a reliable description of pion scattering and other medium effects is needed for these purposes. We build a universal model describing both pion scattering and photoproduction on spin-zero nuclei within the same framework. We develop second-order momentum...
By extracting the transition amplitudes, we give the first lattice QCD prediction of the two-body decay partial widths of the $1^{-+}$ charmoniumlike hybrid $\eta_{c1}$. Given the calculated mass value $m_{\eta_{c1}}=4.329(36)$ GeV, the $\eta_{c1}$ decay is dominated by the open charm modes $D_1\bar{D}$, $D^*\bar{D}$ and $D^*\bar{D}^*$ with partial widths of $258(133)$ MeV, $88(18)$ MeV and...
K$^*$(892) production from nuclei provides a crucial test ground for exploring possible in-medium modification of K$^*$(892) properties. Recently, we collected high-statistics datasets for $^{12}$C(K$^-$,p) reactions at 1.8 GeV/c. We performed this measurement simultaneously in the J-PARC E42 run for the H-dibaryon search. The HypTPC helps reconstruct the K$^*$(892)-> K$^0_{s}\pi^-$ decay,...
The search for Dark Matter is an integral part of New Physics searches, however, Dark Matter has yet to be observed directly. Theoretical models provide a large parameter space for Dark Matter and allow for different properties of the particles. Models incorporating so-called portal interactions, where Dark Matter interacts with Standard Model particles through a mediator particle, are of...
The anomalous magnetic moment of the muon, $a_\mu = (g-2)_\mu/2$, is one of the most precisely measured observables of the Standard Model. However, its value shows a sizeable discrepancy to the Standard Model prediction. It is still under discussion whether this discrepancy is a hint for New Physics or a proof for the limited understanding of strong interaction at low energies. To get a better...
With the large datasets on 𝑒+𝑒−-annihilation at the 𝐽/𝜓 and 𝜓(3686) resonances collected at the BESIII experiment, multi-dimensional analyses making use of polarization and entanglement can shed new light on the production and decay properties hyperon-antihyperon pairs. In a series of recent studies performed at BESIII, significant transverse polarization of the (anti)hyperons has been...
It is experimentally and theoretically challenging to determine the exact number of exited nucleon states and their properties, since the short lifetime of these exited states leads to strongly overlapping resonances. Using a polarized beam, a polarized target or using the polarization of the recoil nucleon helps to measure single or double polarization observables, that are needed for an...
We propose a novel direct search experiment for X17 using the photon-deuteron reaction $\gamma d \to e^+ e^- pn$. X17 is a hypothetical particle conjectured by the ATOMKI collaboration to explain anomalous signals around 17 MeV in excited ${}^8$Be, ${}^4$He and ${}^{12}$C nuclear decays via internal pair creation. It has been subject to a global experimental and theoretical research program....
In this poster presentation, I will discuss the two-photon exchange (TPE) as a crucial higher-order contribution to lepton-proton scattering and the theory of light muonic atoms. In particular, I will focus on the proton polarizability contribution as the dominant uncertainty in the theory prediction of the Lamb shift and the hyperfine splitting (HFS) in muonic hydrogen ($\mu$H). It is...
A(i)DAPT is a program which aims to utilize AI techniques, in particular generative modeling, to support Nuclear and High Energy Physics experiments. Its purpose is to extract physics directly from data in the most complete manner possible. Generative models such GANs and Normalizing Flows are employed to capture the full correlations between particles in the final state of nuclear reactions....
We present results for the charged and neutral pion polarizabilities, obtained through a dispersive analysis of the photon-photon fusion process. This analysis is motivated by the current and future measurements at COMPASS and JLab (Hall D). While the predictions based on the unsubtracted dispersion relation, considering only the pion-pole left-hand cut, provide a relatively good qualitative...
Axions and axion-like particles (ALPs) are one of the most widely discussed extensions of the Standard Model when it comes to the strong CP problem and dark matter candidates. Current experiments are focused on the indirect searches of invisible pseudoscalars in a wide parameter range. In this paper we investigate limits on ALP mass, and its couplings to photons and leptons from 3-photon...
Lattice QCD (LQCD) has proven to be an important tool in understanding the tension between the experimental value for the anomalous magnetic moment of the muon and its standard model prediction. The lattice gives an unique insight to the hadronic sector, which contributes the largest amount to the uncertainty of the theoretical prediction. The common method for evaluating the hadronic vacuum...
Spectroscopy experiments at the precision frontier allow us to study low-energy nuclear structure, test bound-state QED, refine fundamental constants, and potentially find New Physics. As the experimental uncertainties are continuously improved, theory predictions need to follow suit.
The finite-size corrections to the spectra of hydrogen-like atoms are often expanded in terms of the moments...
