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Nuclear Theory·nucl-th

Thursday·February 10, 2022

9 papers—6 primary·3 cross-listed

All9Primary6Cross-lists3
  1. 07

    Radiative corrections to elastic muon-proton scattering at low momentum transfers

    Norbert Kaiser🇩🇪 · Yong-Hui Lin🇩🇪 · Ulf-G. Meißner🇩🇪

    We systematically calculate the radiative corrections of order to elastic muon-proton scattering at low momentum transfers. These include vacuum polarization, photon-loop form factors of the muon and the proton, two-photon exchange corrections and soft photon radiation. In particular, we discuss these corrections for the kinematics of the upcomimg AMBER experiment with a GeV muon beam energy. It is found that for the ratio to the Born cross section, only the minor terms from the photon-loop form factors of the proton and two-photon exchange depend on the proton structure predetermined by the strong interactions. Since a prominent role among the radiative corrections is played by soft photon radiation, the calculation of the bremsstrahlung process should be extended beyond the soft photon approximation and tailored to the specific experimental conditions.

    ↳ hep-phhep-exnucl-exnucl-thPRD(2022)·9 citations
  2. 08

    u-Channel Color Transparency Observables

    G.M. Huber🇨🇦 · W.B. Li🇺🇸 · W. Cosyn🇺🇸 · B. Pire🇫🇷

    We propose to study the onset of color transparency in hard exclusive reactions in the backward regime. Guided by the encouraging JLab results on backward pion and omega electro-production data at moderate Q^2, which may be interpreted as the signal of an early scaling regime where the scattering amplitude factorizes in a hard coefficient function convoluted with nucleon to meson transition distribution amplitudes, we show that the study of these channels on nuclear targets opens a new opportunity to test the appearance of nuclear color transparency for a fast moving nucleon.

    ↳ hep-phnucl-exnucl-thMDPI Physics(2022)·13 citations
  3. 09

    Electromagnetic and strong isospin breaking in light meson masses

    Ángel S. Miramontes🇲🇽 · Reinhard Alkofer🇦🇹 · Christian S. Fischer🇩🇪 · Hèlios Sanchis-Alepuz🇦🇹

    We study electromagnetic as well as strong isospin breaking effects in the isospin mass splittings of light pseudoscalar and vector mesons. To this end we employ a coupled system of quark Dyson-Schwinger and meson Bethe-Salpeter equations whose interaction kernels contain gluon, pion and photon exchange interactions. In bound states, QCD-induced isospin breaking is manifest on different levels. On the one hand, a different explicit up- and down-quark mass directly affects the propagators of the constituent quarks. On the other hand, it leads to different interaction kernels within the isospin multiplets. In addition, electromagnetic isospin breaking is induced via a photon exchange diagram. Using the kaon iso-doublet and the charged pion masses as input to determine the up, down and strange quark masses we find for the pion, kaon and rho meson mass splittings different patterns each. In particular, our results provide evidence that the effects from two sources of mass splittings, the different quark masses and the different quark charges, do not add up linearly.

    ↳ hep-phhep-latnucl-thPLB(2022)·12 citations

Affiliations

first authorsco-authorsvia INSPIRE