Abstract: The low-lying excited states in the neutron-deficient N = Z + 1 nucleus (87)(43)Tcc(44) have been studied via the fusion-evaporation reaction Fe-54(Ar-36, 2n1p)Tc-87 at the Grand Accelerateur National d'Ions Lourds (GANIL), France. The AGATA spectrometer was used in conjunction with the auxiliary NEDA, Neutron Wall, and DIAMANT detector arrays to measure coincident prompt gamma rays, neutrons, and charged particles emitted in the reaction. A level scheme of Tc-87 from the (9/2(g.s.)(+)) state to the (33/2(1)(+)) state was established based on six mutually coincident gamma-ray transitions. The constructed level structure exhibits a rotational behavior with a sharp backbending at (h) over bar omega approximate to 0.50 MeV. A decrease in alignment frequency and increase in alignment sharpness in the odd-mass isotonic chains around N = 44 is proposed as an effect of the enhanced isoscalar neutron-proton interactions in odd-mass nuclei when approaching the N = Z line.

Abstract: Exclusive dimuon production in ultraperipheral collisions (UPC), resulting from photon-photon interactions in the strong electromagnetic fields of colliding high-energy lead nuclei, PbPb(gamma gamma) -> mu(+) mu(-) (Pb-(*Pb-)(()*())), is studied using L-int = 0.48 nb(-1) of root S-NN = 5.02 TeV lead-lead collision data at the LHC with the ATLAS detector. Dimuon pairs are measured in the fiducial region p(T,mu) > 4 GeV, vertical bar eta(mu)vertical bar < 2.4, invariant m(mu mu) > 10 GeV, and p(T,mu mu) <2 GeV. The primary background from single-dissociative processes is extracted from the data using a template fitting technique. Differential cross sections are presented as a function of m(mu mu), absolute pair rapidity (vertical bar y(mu mu)vertical bar), scattering angle in the dimuon rest frame (vertical bar cos v*(mu mu)vertical bar), and the colliding photon energies. The total cross section of the UPC gamma gamma -> mu(+) mu(-) process in the fiducial volume is measured to be sigma(mu mu)(fid) = 34.1 +0.3(stat.)+0.7(syst.) μb. Generally good agreement is found with calculations from STARlight, which incorporate the leading-order Breit-Wheeler process with no final-state effects, albeit differences between the measurements and theoretical expectations are observed. In particular, the measured cross sections at larger vertical bar y(mu mu)vertical bar are found to be about 10-20% larger in data than in the calculations, suggesting the presence of larger fluxes of photons in the initial state. Modification of the dimuon cross sections in the presence of forward and/or backward neutron production is also studied and is found to be associated with a harder incoming photon spectrum, consistent with expectations.

Abstract: The Al-26(n, p) Mg-26 reaction is the key reaction impacting on the abundances of the cosmic gamma-ray emitter Al-26 produced in massive stars and impacts on the potential pollution of the early solar system with Al-26 by asymptotic giant branch stars. We performed a measurement of the Al-26(n, p) Mg-26 cross section at the high-flux beam line EAR-2 at the n_TOF facility (CERN). We report resonance strengths for eleven resonances, nine being measured for the first time, while there is only one previous measurement for the other two. Our resonance strengths are significantly lower than the only previous values available. Our cross-section data range to 150 keV neutron energy, which is sufficient for a reliable determination of astrophysical reactivities up to 0.5 GK stellar temperature.

Abstract: A measurement of the CP asymmetry in D-0 -> (KSKS0)-K-0 decays is reported, based on a data sample of proton-proton collisions collected by the LHCb experiment from 2015 to 2018, corresponding to an integrated luminosity of 6 fb(-1). The flavor of the D-0 candidate is determined using the charge of the D-*+/- meson, from which the decay is required to originate. The D-0 -> K+K- decay is used as a calibration channel. The time-integrated CP asymmetry for the D-0 -> (KSKS0)-K-0 mode is measured to be A(CP)(D-0 -> (KSKS0)-K-0) = (-3.1 +/- 1.2 +/- 0.4 +/- 0.2), where the first uncertainty is statistical, the second is systematic, and the third is due to the uncertainty on the CP asymmetry of the calibration channel. This is the most precise determination of this quantity to date.

Abstract: A search for pair production of bottom squarks in events with hadronically decaying t-leptons, b-tagged jets, and large missing transverse momentum is presented. The analyzed dataset is based on proton-proton collisions at root s = 13 TeV delivered by the Large Hadron Collider and recorded by the ATLAS detector from 2015 to 2018, and corresponds to an integrated luminosity of 139 fb(-1). The observed data are compatible with the expected Standard Model background. Results are interpreted in a simplified model where each bottom squark is assumed to decay into the second-lightest neutralino (chi) over tilde (0)(2) and a bottom quark, with (chi) over tilde (0)(2) decaying into a Higgs boson and the lightest neutralino (chi) over tilde1(0). The search focuses on final states where at least one Higgs boson decays into a pair of hadronically decaying t-leptons. This allows the acceptance and thus the sensitivity to be significantly improved relative to the previous results at low masses of the (chi) over tilde (0)(2), where bottom-squark masses up to 850 GeV are excluded at the 95% confidence level, assuming a mass difference of 130 GeV between (chi) over tilde (0)(2) and (chi) over tilde (0)(1). Model-independent upper limits are also set on the cross section of processes beyond the Standard Model.