Relating CP-violating decays to the neutron EDM

We use the present upper bound on the neutron electric dipole moment to give an estimate for the upper limit of the CP-violating couplings of the $\eta(\eta')$ meson to the neutron. Using this result, we derive constraints on the CP-violating two-pion decays of the $\eta(\eta')$. Our results are relevant for the running and planned GlueX and LHCb measurements of rare meson decays.Comment: NSTAR 2017 conference proceeding

Lowest-lying spin-1/2 and spin-3/2 baryon magnetic moments in chiral perturbation theory

5th International Conference on Quarks and Nuclear Physics (QNP09). Inst High Energy Phys Chinese Acad Sci, Beijing, PEOPLES R CHINA, SEP 21-25, 2009We review some recent progress in our understanding of the lowest-lying spin-1/2 and spin-3/2 baryon magnetic moments (MMs) in terms of Chiral Perturbation Theory (ChPT) In particular, we show that at next-to-leading-order ChPT can describe the MMs of the octet baryons quite well We also make predictions for the decuplet MMs at the same chiral order Among them, the MMs of the Delta(++) and Delta(+) ate found to agree well with data within the experimental uncertainties.This work was partially supported by the MEC grant FIS2006-03438 and the European Community- Research Infrastructure Integrating Activity Study of Strongly Interacting Matter (Hadron-Physics2, Grant Agreement 227431) under the Seventh Framework Programme of EU. L.S.G. acknowledges support from the MICINN in the Program “Juan de la Cierva.” J.M.C. acknowledges the same institution for a FPU grant

CP-violating decays of the pseudoscalars η and η' and their connection to the electric dipole moment of the neutron

Using the present upper bound on the neutron electric dipole moment, we give an estimate for the upper limit of the CP-violating couplings of the eta(eta') to the nucleon. Using this result, we then derive constraints on the CP-violating eta(eta')-pi-pi couplings, which define the two-pion CP-violating decays of the eta and eta' mesons. Our results are relevant for the running and planned measurements of rare decays of the eta and eta' mesons by the GlueX Collaboration at JLab and the LHCb Collaboration at CERN

Recent topics of mesic atoms and mesic nuclei -- ϕ\phi mesic nuclei exist ?--

We study $\phi$-meson production in nuclei to investigate the in-medium modification of the $\phi$-meson spectral function at finite density. We consider (${\bar p},\phi$), ($\gamma,p$) and ($\pi^-,n$) reactions to produce a $\phi$-meson inside the nucleus and evaluate the effects of the medium modifications to reaction cross sections. The structures of the bound states, $\phi$-mesic nuclei, are also studied. For strong absorptive interaction cases, we need to know the spectrum shape in a wide energy region to deduce the properties of $\phi$.Comment: Talk given at EXA08, Vienna, September 2008. To be published in the Proceedings, Hyperfine Interactions. 6 pages, 6 figure

Neutral-current weak pion production off the nucleon in covariant chiral perturbation theory

Neutral current single pion production induced by neutrinos and antineutrinos on nucleon targets has been investigated in manifestly relativistic baryon chiral perturbation theory with explicit Δ(1232)degrees of freedom up to O(p). At low energies, where chiral perturbation theory is applicable, the total cross sections for the different reaction channels exhibit a sizable non-resonant contribution, which is not present in event generators of broad use in neutrino oscillation and cross section experiments such as GENIE and NuWro.Peer Reviewe

Pion photoproduction off nucleons in covariant chiral perturbation theory

Pion photoproduction off the nucleon close to threshold is studied in covariant baryon chiral perturbation theory at O(p3) in the extended-on-mass-shell scheme, with the explicit inclusion of the Δ(1232) resonance using the δ counting. The theory is compared to the available data of cross sections and polarization observables for all the charge channels. Most of the necessary low-energy constants are well known from the analysis of other processes and the comparison with data constrains some of the still unknown ones. The Δ(1232) contribution is significant in improving the agreement with data, even at the low energies considered