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The leptonic tensor for the process $e^+ e^- \to \gamma+\gamma^*$, which describes the next-to-leading order virtual and soft QED corrections to initial state radiation in $e^+ e^-$ annihilation with emission of an extra virtual photon…
The radiative return is a new method for hadronic cross section measurements at electron-positron colliders, which are operated at a fixed center-of-mass energy. In order to lower the effective hadronic mass M_hadr only such events are…
A precise measurement of the cross section of the process e+ e- to pi+ pi- (gamma) from threshold to an energy of 3 GeV is obtained with the initial state radiation (ISR) method using 232 fb^-1 of data collected with the BABAR detector at…
The hadronic vacuum polarization contribution to the muon (g-2) value is calculated by considering a known dispersion integral which involves the $R_{e+ e-}(s)$ ratio. The theoretical part stemming from the region below 1.8 GeV is the…
This paper presents a new explanation of the width of gamma-ray spectra based on Rahm's electronegativity scale. This quantitatively proves, for the first time, that positrophilic electrons in the positron-electron annihilation process are…
I review recent estimates of the non-perturbative hadronic vacuum polarization contributions. Since these at present can only be evaluated in terms of experimental data of limited precision, the related uncertainties pose a serious…
The hadronic vacuum polarization (HVP) contributions to the muon $g$$-$$2$ are the crucial quantity to resolve whether new physics is present or not in the comparison between the Standard Model (SM) prediction and experimental measurements…
The experimental value of g-2 of the muon is larger by $4.2 \sigma$ than the Standard Model prediction based on the hadronic vacuum polarization contribution (HVP) determined from the measured R-ratio, $\sigma(e^+e^- \! \rightarrow \!…
A new measurement of the cosmic ray positron fraction in the energy range of 1-50 GeV is presented. The measurement is based on data taken by the AMS-01 experiment during its 10 day space shuttle flight in June 1998. A proton background…
The Standard Model prediction for muon-electron scattering beyond leading order requires the inclusion of QCD contributions which cannot be computed perturbatively. At next-to- and next-to-next-to-leading order, they arise from one- and…
We use recently evaluated radiative and nonperturbative corrections to production of heavy quarks by a vector current to give very precise theoretical calculations of the high energy ($t^{1/2}\geq \sqrt{2}$ GeV) imaginary part of the photon…
The Polarized Atomic Hydrogen Gas Jet Target polarimeter (HJET) is used to measure the absolute proton beam polarization, $\sigma_P^\text{syst}/P\!\lesssim\!0.5\%$, at the Relativistic Heavy Ion Collider. Here I consider the possibility of…
The description of the polarized quark hadronization process is one of the most challenging problems in the physics of strong interactions. The various single hadron and dihadron fragmentation functions, that quantify this process, are…
We present preliminary measurements of electron and positron spectra in d+Au and p+p collisions at $\sqrt{s_{NN}}=200$ GeV for $1.5 < p_{T} < 7.0$ GeV/c. These measurements were carried out using the STAR Time Projection Chamber (TPC) and…
The measurement of the hadronic cross-section in $e^+ e^-$ annihilation at high luminosity factories using the radiative return method is motivated and discussed. A Monte Carlo generator which simulates the radiative process $e^+ e^- \to…
To probe CP violation in the leptonic sector using GeV energy neutrino beams in current and future experiments using argon detectors, precise models of the complex underlying neutrino and antineutrino interactions are needed. The E12-14-012…
We report a measurement of the energy-dependent total charged-current cross section $\sigma\left(E_\nu\right)$ for inclusive muon neutrinos scattering on argon, as well as measurements of flux-averaged differential cross sections as a…
Whether studying neutrinos for their own sake or as a messenger particle, neutrino cross sections are critically important for numerous analyses. On the low energy side, measurements from accelerator experiments reach up to a few 100s of…
In the fixed energy environment of the $e^{+}e^{-}$ collider DA$\Phi$NE, KLOE can measure the cross section of the process $e^{+}e^{-} \to$ hadrons as a function of the hadronic system energy using the radiative return. At energies below 1…
Recent precision measurements of the flux of cosmic ray positrons by the Alpha Magnetic Spectrometer show that the spectrum has a marked softening feature for energies close to one TeV. A possible interpretation of this result is that the…