Radiative corrections: from medium to high energy experiments.

Radiative corrections are crucial for modern high-precision physics experiments, and are an area of active research in the experimental and theoretical community. Here we provide an overview of the state of the field of radiative corrections with a focus on several topics: lepton-proton scattering, QED corrections in deep-inelastic scattering, and in radiative light-hadron decays. Particular emphasis is placed on the two-photon exchange, believed to be responsible for the proton form-factor discrepancy, and associated Monte-Carlo codes.

QCD Running Coupling in the Nonperturbative and Near-Perturbative Regimes.

We use analytic continuation to extend the gauge-gravity duality nonperturbative description of the strong force coupling into the transition, near-perturbative, regime where perturbative effects become important. By excluding the unphysical region in coupling space from the flow of singularities in the complex plane, we derive a specific relation between the scales relevant at large and short distances; this relation is uniquely fixed by requiring maximal analyticity. The unified effective coupling model gives an accurate description of the data in the nonperturbative and the near-perturbative regions.

QCD Predictions for Meson Electromagnetic Form Factors at High Momenta: Testing Factorization in Exclusive Processes.

We report the first lattice QCD computation of pion and kaon electromagnetic form factors, F_{M}(Q^{2}), at large momentum transfer up to 10 and 28  GeV^{2}, respectively. Utilizing physical masses and two fine lattices, we achieve good agreement with JLab experimental results at Q^{2}≲4  GeV^{2}. For Q^{2}≳4  GeV^{2}, our results provide ab initio QCD benchmarks for the forthcoming experiments at JLab 12 GeV and future electron-ion colliders.

Unveiling Baryon Charge Carriers through Charge Stopping in Isobar Collisions.

Utilizing a comprehensive (3+1)D relativistic hydrodynamic framework with multiple conserved charge currents and charge-dependent lattice-QCD-based equation of state, we study the baryon and electric charge number deposition at midrapidity in isobar Ru+Ru and Zr+Zr collisions at the center of mass energy sqrt[s_{NN}]=200  GeV. Comparing our predictions with upcoming experimental data from the Relativistic Heavy Ion Collider will shed light on the existence of baryon junctions.

Nucleon Electric Polarizabilities and Nucleon-Pion Scattering at the Physical Pion Mass.

We present a lattice QCD calculation of the nucleon electric polarizabilities at the physical pion mass. Our findings reveal the substantial contributions of the Nπ states to these polarizabilities. Without considering these contributions, the lattice results fall significantly below the experimental values, consistent with previous lattice studies.

Probing the Quark Orbital Angular Momentum at Electron-Ion Colliders Using Exclusive π^{0} Production.

We propose to detect signals from quark orbital angular momentum (OAM) through exclusive π^{0} production in electron- (longitudinally polarized) proton collisions. Our analysis demonstrates that the sin2ϕ azimuthal angular correlation between the transverse momentum of the scattered electron and the recoil proton serves as a sensitive probe of quark OAM. Additionally, we present a numerical estimate of the asymmetry associated with this correlation for the kinematics accessible at the Electron-Ion Colliders in the U.

Lattice QCD Calculation of Electroweak Box Contributions to Superallowed Nuclear and Neutron Beta Decays.

We present the first lattice QCD calculation of the universal axial γW-box contribution □_{γW}^{VA} to both superallowed nuclear and neutron beta decays. This contribution emerges as a significant component within the theoretical uncertainties surrounding the extraction of |V_{ud}| from superallowed decays. Our calculation is conducted using two domain wall fermion ensembles at the physical pion mass.

Transversity Distributions and Tensor Charges of the Nucleon: Extraction from Dihadron Production and Their Universal Nature.

We perform the first global quantum chromodynamics (QCD) analysis of dihadron production for a comprehensive set of data in electron-positron annihilation, semi-inclusive deep-inelastic scattering, and proton-proton collisions, from which we extract simultaneously the transversity distributions of the nucleon and π^{+}π^{-} dihadron fragmentation functions. We incorporate in our fits known theoretical constraints on transversity, namely, its small-x asymptotic behavior and the Soffer bound. We furthermore show that lattice-QCD results for the tensor charges can be successfully included in the analysis.

Viscosities of the Baryon-Rich Quark-Gluon Plasma from Beam Energy Scan Data.

This work presents the first Bayesian inference study of the (3+1)D dynamics of relativistic heavy-ion collisions and quark-gluon plasma viscosities using an event-by-event (3+1)D hydrodynamics+hadronic transport theoretical framework and data from the Relativistic Heavy Ion Collider Beam energy scan program. Robust constraints on initial state nuclear stopping and the baryon chemical potential-dependent shear viscosity of the produced quantum chromodynamic (QCD) matter are obtained. The specific bulk viscosity of the QCD matter is found to exhibit a preferred maximum around sqrt[s_{NN}]=19.

Unveiling the dynamics of little-bang nucleosynthesis.

High-energy nuclear collisions provide a unique site for the synthesis of both nuclei and antinuclei at temperatures of kT ≈ 100 - 150 MeV. In these little bangs of transient collisions, a quark-gluon plasma (QGP) of nearly vanishing viscosity is created, which is believed to have existed in the early universe within the first few microseconds after the Big Bang. Analyses of identified particles produced in these little bangs based on the statistical hadronization model for the QGP have suggested that light (anti)nuclei are produced from the QGP as other hadrons and their abundances are little affected by later hadronic dynamics.

Nucleon Transversity Distribution in the Continuum and Physical Mass Limit from Lattice QCD.

We report a state-of-the-art lattice QCD calculation of the isovector quark transversity distribution of the proton in the continuum and physical mass limit using large-momentum effective theory. The calculation is done at four lattice spacings a={0.098,0.

Multiscale Imaging of Nuclear Deformation at the Electron-Ion Collider.

We show within the color glass condensate framework that exclusive vector meson production at high energy is very sensitive to the geometric deformation of the target nucleus at multiple length scales. We show that different multipole deformation parameters affect different regions of transverse momentum transfer. These results have two important consequences: (1) Deformations of nuclear targets need to be taken into account when making predictions for and interpreting certain observables at the EIC.

Measurement of Direct-Photon Cross Section and Double-Helicity Asymmetry at sqrt[s]=510 GeV in p[over →]+p[over →] Collisions.

We present measurements of the cross section and double-helicity asymmetry A_{LL} of direct-photon production in p[over →]+p[over →] collisions at sqrt[s]=510  GeV. The measurements have been performed at midrapidity (|η|<0.25) with the PHENIX detector at the Relativistic Heavy Ion Collider.

Evidence of Hexadecapole Deformation in Uranium-238 at the Relativistic Heavy Ion Collider.

State-of-the-art hydrodynamic simulations of the quark-gluon plasma are unable to reproduce the elliptic flow of particles observed at the BNL Relativistic Heavy Ion Collider (RHIC) in relativistic ^{238}U+^{238}U collisions when they rely on information obtained from low-energy experiments for the implementation of deformation in the colliding ^{238}U ions. We show that this is due to an inappropriate treatment of well-deformed nuclei in the modeling of the initial conditions of the quark-gluon plasma. Past studies have identified the deformation of the nuclear surface with that of the nuclear volume, though these are different concepts.

Small-x Evolution of the Gluon Generalized Parton Distribution E_{g} of the Nucleon.

We study the small-x evolution equation for the gluon generalized parton distribution E_{g} of the nucleon. It is shown that E_{g} at vanishing skewness exhibits the Regge behavior identical to the Balitsky-Fadin-Kuraev-Lipatov pomeron despite its association with nucleon helicity-flip processes. We also consider the effect of gluon saturation and demonstrate that E_{g} gets saturated in the same way as its helicity-nonflip counterpart H_{g}.

Collectivity in Ultraperipheral Pb+Pb Collisions at the Large Hadron Collider.

We present the first full (3+1)D dynamical simulations of ultraperipheral Pb+Pb collisions at the Large Hadron Collider. Extrapolating from p+Pb collisions, we explore whether a quasireal photon γ^{*} interacting with the lead nucleus in an ultraperipheral collision can create a many-body system exhibiting fluid behavior. Assuming strong final-state interactions, we provide model results for charged hadron multiplicity, identified particle mean transverse momenta, and charged hadron anisotropic flow coefficients, and compare them with experimental data from the ALICE and ATLAS Collaborations.

Signature of the Gluon Orbital Angular Momentum.

We propose a novel observable for the experimental detection of the gluon orbital angular momentum (OAM) that constitutes the proton spin sum rule. We consider longitudinal double spin asymmetry in exclusive dijet production in electron-proton scattering and demonstrate that the cosϕ azimuthal angle correlation between the scattered electron and proton is a sensitive probe of the gluon OAM at small x and its interplay with the gluon helicity. We also present a numerical estimate of the cross section for the kinematics of the Electron-Ion Collider.

Probing Gluon Bose Correlations in Deep Inelastic Scattering.

We study correlations originating from the quantum nature of gluons in a hadronic wave function. Bose-Einstein correlation between identical particles lead to the enhancement in the number of pairs of gluons with the same quantum numbers and small relative momentum. We show that these preexisting correlations can be probed in deep inelastic scattering experiments at high energy.

Lattice QCD Calculation of the Two-Photon Exchange Contribution to the Muonic-Hydrogen Lamb Shift.

We develop a method for lattice QCD calculation of the two-photon exchange contribution to the muonic-hydrogen Lamb shift. To demonstrate its feasibility, we present the first lattice calculation with a gauge ensemble at m_{π}=142  MeV. By adopting the infinite-volume reconstruction method along with an optimized subtraction scheme, we obtain with statistical uncertainty ΔE_{TPE}=-28.

Measurement of Two-Particle Correlations of Hadrons in e^{+}e^{-} Collisions at Belle.

The measurement of two-particle angular correlation functions in high-multiplicity e^{+}e^{-} collisions at sqrt[s]=10.52  GeV is reported. In this study, the 89.

Lattice QCD Determination of the Bjorken-x Dependence of Parton Distribution Functions at Next-to-Next-to-Leading Order.

We report the first lattice QCD calculation of pion valence quark distribution with next-to-next-to-leading order perturbative matching correction, which is done using two fine lattices with spacings a=0.04 and 0.06 fm and valence pion mass m_{π}=300  MeV, at boost momentum as large as 2.

Lattice QCD Calculation of the Pion Mass Splitting.

We use the infinite volume reconstruction method to calculate the charged and neutral pion mass difference. The hadronic tensor is calculated using lattice QCD and then combined with an analytic photon propagator, and the mass splitting is calculated with exponentially suppressed finite-volume errors. The calculation is performed using six gauge ensembles generated with 2+1-flavor domain wall fermions, and five ensembles are at the physical pion mass.

Constraining the Nucleon Size with Relativistic Nuclear Collisions.

The notion of the "size" of nucleons and their constituents plays a pivotal role in the current paradigm of the formation and the fluctuations of the quark-gluon plasma produced in high-energy nuclear collision experiments. We report on state-of-the-art hydrodynamic results showing that the correlation between anisotropic flow v_{n}^{2} and the mean transverse momentum of hadrons [p_{t}] possesses a unique sensitivity to the nucleon size in off-central heavy-ion collisions. We argue that existing experimental measurements of this observable support a picture where the relevant length scale characterizing the colliding nucleons is of order 0.

Cone-Size Dependence of Jet Suppression in Heavy-Ion Collisions.

The strong suppression of high-p_{T} jets in heavy-ion collisions is a result of elastic and inelastic energy loss suffered by the jet multiprong collection of color charges that are resolved by medium interactions. Hence, quenching effects depend on the fluctuations of the jet substructure that are probed by the cone-size dependence of the spectrum. In this Letter, we present the first complete, analytic calculation of the inclusive R-dependent jet spectrum in PbPb collisions at LHC energies, including resummation of energy loss effects from hard, vacuumlike emissions occurring in the medium and modeling of soft energy flow and recovery at the jet cone.

Probing Gluon Spin-Momentum Correlations in Transversely Polarized Protons through Midrapidity Isolated Direct Photons in p^{↑}+p Collisions at sqrt[s]=200 GeV.

Studying spin-momentum correlations in hadronic collisions offers a glimpse into a three-dimensional picture of proton structure. The transverse single-spin asymmetry for midrapidity isolated direct photons in p^{↑}+p collisions at sqrt[s]=200  GeV is measured with the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). Because direct photons in particular are produced from the hard scattering and do not interact via the strong force, this measurement is a clean probe of initial-state spin-momentum correlations inside the proton and is in particular sensitive to gluon interference effects within the proton.