No Arabic abstract
Radiative corrections are calculated for antineutrino proton quasielastic scattering, neutrino deuteron scattering, and the asymmetry of polarised neutron beta decay from which $G_{A}/G_{V}$ is determined. A particular emphasis is given to the constant parts that are usually absorbed into the coupling constants, and thereby those that appear in the processes that concern us are unambiguously tied among each other.
The inverse $beta$-decay reaction, $ bar{ u}_e p to e^+ n$, for low-energy anti-neutrinos coming from nuclear reactors is of great current interest in connection with high-precision measurements of the neutrino mixing angle $theta_{13}$. We have derived analytic expressions, up to next-to-leading order in heavy-baryon chiral perturbation theory, for the radiative corrections (RCs) and the nucleon-recoil corrections both for this reaction and for the related neutron $beta$-decay process. We show that the recoil corrections, which include the weak magnetism contribution, are small for neutron $beta$-decay, but for inverse $beta$-decay, the recoil corrections are comparable in size to the RCs for typical energies of reactor anti-neutrinos, and they have opposite signs. The RCs and the recoil corrections exhibit very different dependences on the neutrino energy.
The differential cross section for elastic scattering of deuterons on electrons at rest is calculated taking into account the QED radiative corrections to the leptonic part of interaction. These model-independent radiative corrections arise due to emission of the virtual and real soft and hard photons as well as to vacuum polarization. We consider an experimental setup where both final particles are recorded in coincidence and their energies are determined within some uncertainties. The kinematics, the cross section, and the radiative corrections are calculated and numerical results are presented.
Neutrino oscillation experiments at accelerator energies aim to establish CP violation in the neutrino sector by measuring the energy-dependent rate of $ u_e$ appearance and $ u_mu$ disappearance in a $ u_mu$ beam. Extracting the correct oscillation rate demands control over QED radiative corrections at the percent level. Focusing on the critical charged-current neutrino-nucleon scattering process, we show that the cross section factorizes into two pieces. The first piece depends on hadron structure but is universal for $ u_e$ and $ u_mu$, and hence constrained by high-statistics $ u_mu$ data. The second piece is nonuniversal and suffers large logarithm enhancements, but is computed to high precision using renormalization group improved perturbation theory. Our results provide a missing ingredient for the robust interpretation of current NOvA and T2K experiments, and can be applied to future experiments such as DUNE and HyperK.
In interpreting the SNO experiments, accurate estimates of the u d reaction cross sections are of great importance. In our recent work, we have improved our previous calculation by updating some of its inputs and by incorporating the results of a recent effective-field-theoretical calculation. The new cross sections are slightly (sim 1%) larger than the previously reported values. It is reasonable to assign 1% uncertainty to the u d cross sections reported here; this error estimate does not include radiative corrections.
Radiative corrections to the annihilation of proton--antiproton into electron--positron are revisited, including virtual and real (soft and hard) photon emission. This issue is relevant for the time-like form factors measurements planned at the PANDA experiment at the FAIR facility, in next future. The relevant formulas are given. A stand-alone Monte-Carlo integrator is developed on the basis of the calculated radiative cross section and its application to the PANDA experiment is illustrated.