The heavy-ion collisions can produce extremely strong transient magnetic and electric fields. We study the azimuthal fluctuation of these fields and their correlations with the also fluctuating matter geometry (characterized by the participant plane harmonics) using event-by-event simulations. A sizable suppression of the angular correlations between the magnetic field and the 2nd and 4th harmonic participant planes is found in very central and very peripheral collisions, while the magnitudes of these correlations peak around impact parameter b ∼ 8 − 10fm for RHIC collisions. This can lead to notable impacts on a number of observables related to various magnetic field induced effects, and our finding suggests that the optimal event class for measuring them should be that corresponding to b ∼ 8 − 10 fm.

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We report a leading-order calculation of radiative 7 Li neutron captures to both the ground and first excited state of 8 Li in the framework of a low-energy effective field theory (Halo-EFT). Each of the possible final states is treated as a shallow bound state composed of both n + 7 Li and n + 7 Li * (core excitation) configurations. The ab initio variational Monte Carlo method is used to compute the asymptotic normalization coefficients of these bound states, which are then used to fix couplings in our EFT. We calculate the total and partial cross sections in the radiative capture process using this calibrated EFT. Fair agreement with measured total cross sections is achieved and excellent agreement with the measured branching ratio between the two final states is found. In contrast,a previous Halo-EFT calculation [G. Rupak and R. Higa, Phys. Rev. Lett 106, 222501 (2011)] assumes that the n-7 Li couplings in different spin channels are equal, fits the P -wave "effectiverange" parameter to the threshold cross section for 7 Li + n → 8 Li + γ, and assumes the core excitation is at high enough energy scale that it can be integrated out.

This report summarizes our study of Neutral Current (NC)-induced photon production in Mini-BooNE, as motivated by the low energy excess in this experiment [A. A. Aquilar-Arevalo et al. (MiniBooNE Collaboration), Phys. Rev. Lett. 98, 231801 (2007); 103, 111801 (2009)]. It was proposed that NC photon production with two anomalous photon-Z boson-vector meson couplings might explain the excess. However, our computed event numbers in both neutrino and antineutrino runs are consistent with the previous MiniBooNE estimate that is based on their pion production measurement. Various nuclear effects discussed in our previous works, including nucleon Fermi motion, Pauli blocking, and the ∆ resonance broadening in the nucleus, are taken into account. Uncertainty due to the two anomalous terms and nuclear effects are studied in a conservative way.