Abstract: The A 1405 has been one of the most controversial exotic baryons. If the A 1405 possesses a two-pole molecular structure, these poles are expected to evolve differently towards the SU(3) limit. From an analysis of a recent LQCD simulation on the pi Sigma -(K) over barN scattering for I 0 and the study of the quark mass dependence of the octet baryon masses, we determine for the first time the trajectories of these poles towards the symmetric point over the Tr[M] = C trajectory accurately. At m(pi) similar or equal to 200 MeV, our results are consistent with the lattice simulations, and the extrapolations to the physical point, based on the NLO chiral Lagrangians, agree well with existing experimental analyses. We predict qualitatively similar trajectories at LO and up to NLO, consistent with the LO interaction's dominance. At the SU(3) symmetric point of this trajectory, both poles are on the physical sheet, and the lower pole is located at E(1) =1573(6)(6) MeV, becoming a SU(3) singlet, while the higher pole at E ((8a)) = 1589 (7) (5) MeV couples to the octet representation. Moreover, we make predictions in I = 1 for the E resonance. We find a resonance pole that evolves into a bound state around m(pi) = 415 MeV in this sector. The results presented here are crucial to shed light on the molecular nature of exotic strange baryon resonances and can be tested in future LQCD simulations.

Abstract: Neural simulation-based inference (NSBI) is a powerful class of machine-learning-based methods for statistical inference that naturally handles high-dimensional parameter estimation without the need to bin data into low-dimensional summary histograms. Such methods are promising for a range of measurements, including at the Large Hadron Collider, where no single observable may be optimal to scan over the entire theoretical phase space under consideration, or where binning data into histograms could result in a loss of sensitivity. This work develops a NSBI framework for statistical inference, using neural networks to estimate probability density ratios, which enables the application to a full-scale analysis. It incorporates a large number of systematic uncertainties, quantifies the uncertainty due to the finite number of events in training samples, develops a method to construct confidence intervals, and demonstrates a series of intermediate diagnostic checks that can be performed to validate the robustness of the method. As an example, the power and feasibility of the method are assessed on simulated data for a simplified version of an off-shell Higgs boson couplings measurement in the four-lepton final states. This approach represents an extension to the standard statistical methodology used by the experiments at the Large Hadron Collider, and can benefit many physics analyses.

Abstract: The CP asymmetry and branching fraction of the Cabibbo-Kobayashi-Maskawa-suppressed decay B+ -> J/psi pi(+) are precisely measured relative to the favored decay B+ -> J/psi K+ using a sample of protonproton collision data corresponding to an integrated luminosity of 5.4 fb(-1) recorded at a center-of-mass energy of 13 TeV during 2016-2018. The results of the CP asymmetry difference and branching fraction ratio are Delta A(CP)= A(CP)(B+ -> J/psi pi(+))-A(CP)(B+ -> J/psi K+)=(1.29 +/- 0.49 +/- 0.08)x10(-2), R-pi/K [B(B+ -> J/psi pi(+))/ B(B+-> J/psi K+)] = (3.852 +/- 0.022 +/- 0.018)x10(-2), where the first uncertainties are statistical and the second are systematic. A combination with previous LHCb results based on data collected at 7 and 8 TeVin 2011 and 2012 yields Delta A(CP) = (1.42 +/- 0.43 +/- 0.08) x 10(-2) and R pi/K = (3.846 +/- 0.018 +/- 0.018) x 10(-2). The combined Delta A(CP) value deviates from zero by 3.2 standard deviations, providing the first evidence for direct CP violation in the amplitudes of beauty decays to charmonium final states.