Abstract This article presents the potential of a combined analysis of the JUNO and KM3NeT/ORCA experiments to determine the neutrino mass ordering. This combination is particularly interesting as it significantly boosts the potential of either detector, beyond simply adding their neutrino mass ordering sensitivities, by removing a degeneracy in the determination of ∆$$ {m}_{31}^2 $$ m 31 2 between the two experiments when assuming the wrong ordering. The study is based on the latest projected performances for JUNO, and on simulation tools using a full Monte Carlo approach to the KM3NeT/ORCA response with a careful assessment of its energy systematics. From this analysis, a 5σ determination of the neutrino mass ordering is expected after 6 years of joint data taking for any value of the oscillation parameters. This sensitivity would be achieved after only 2 years of joint data taking assuming the current global best-fit values for those parameters for normal ordering.

Despite the number of inclusive measurements of the pionic fusion reactions, the nature of the ABC effect discovered in 1960 was not completely established. Exclusive measurements of the doublepion-production reactions leading to either fused d, 3He and 4He nuclear final states or pp pairs are analyzed. A significant ABC effect—enhancement in the region of low ππ mass—is found only in the isoscalar ππ channel while in the isovector channels it is small or absent. For the reaction with isovector pp final state an ABC effect was not observed even at the special kinematic conditions to reproduce a quasi-bound two-proton state. The total cross sections for the d and 4He fusion reactions show similar resonance-like energy dependence.

We report here the results on studying of proton-pion and two-pion correlations in eA interactions at 5 GeV. Kinematic correlations were studied as a function of the two-particle opening angle, their momenta and proton multiplicity. The universal properties of correlation functions were found with respect to different particle species. Interferometry method was used to determine the size of the interaction region.

A new high-transmission experimental setup Lambdameter-2 is described, which is specially designed for the study of cumulative Lambda particles in the region of fragmentation of a target nucleus in the high-energy hadron-nucleus and nucleus-nucleus interactions.

We report the results of analysis of correlations of the product protons from inelastic eA collisions at smallQ2. The experimental data were measured by the ARGUS detector. The correlation effect at small relative momentaq (interference and final state interaction) is closely associated with the angular correlations due to momentum conservation. The examined correlations in eA collisions also show features similar to correlations in hA collisions.

The pion-nucleus transitions of the type A(pi,pi'p(d))X, where pi' is the leading secondary pion emitted at a small angle (theta < 8-degrees) and carrying over a half of the initial beam momentum, and p is a cumulative proton (deuteron) emitted backwards with a production angle in the 120 - 160-degrees interval, are studied. The 3.15 (1.4) GeV/c pion beam is brought into collision with the Al and Pb (Ti and Fe) targets in the FOCUS detector at ITEP. The influence of the energy transfer epsilon = E(pi) - E(pi') to the leading pion on the shape of the cumulative proton (deuteron) spectrum is investigated. The invariant cumulative proton function f=p-1dsigma/dT is fitted with a functional form C exp(-T/T0) for both the reaction under consideration and the inclusive A(pi, p)X process observed in the same experiment. The deviation of the parameter T0 at low epsilon from its inclusive value, associated with the deviation of the cumulative proton spectrum from the exponential form, is interpreted as a kinematical boundary effect. To account for the kinematical boundary, die invariant function is taken in the form f is similar to (1 - T/epsilon) epsilon/T0* for epsilon < epsilon* and f is similar to (1 - T/epsilon*)epsilon*/T0* for epsilon greater-than-or-equal-to epsilon*, where epsilon* is the mean energy of the local excitation of nuclear matter, beginning from which the function f becomes constant. The saturation of the local excitation leads to the scaling behavior of the invariant function. The global fit of all spectra of cumulative protons yields epsilon'= 0.9 - 1.0 GeV.

The correlation functions for pi+ mesons with cumulative baryons and with pi+ mesons have been measured in pA interactions. The proton momentum was 7.5 GeV/c; the nucleus A was C, Ti, or Pb. The results are compared with the results of other studies and are discussed in connection with ideas concerning the space-time picture of hadron-nucleus interactions.

In the process of development of a measuring complex for the study of nuclear reactions at the Institute of Theoretical and Experimental Physics, the FOCUS apparatus was created for simultaneous investigation of the regions of target-nucleus fragmentation and impinging-particle fragmentation. The FOCUS apparatus is based on an MS-12 magnet and the elements of a nonmagnetic hadron spectrometer. The parameters of the apparatus and its calibration procedure are described.

Correlation functions of three cumulative particles have been measured in p(7.5 GeV/c)A, p(3.0 GeV/c)A, and pi+ (3.0 GeV/c)A interactions with nuclei of C, Ti, and Pb. Secondary particles (protons, deuterons, and tritium nuclei) whose separation angles were < 50-degrees and > 130-degrees were recorded at polar angles near 90-degrees. The contribution of specifically ternary correlations is identified and discussed.

The pairing correlation functions of cumulative baryons in pA and pi+ A interactions in the nuclei C, Ti, and Pb have been measured at initial momentum 3 GeV/c. The correlation functions are analyzed as functions of the initial energy and various kinematic variables. The experimental results are compared with the data obtained with a similar setup at initial momentum 7.5 GeV/c. The set of data on the correlation functions is consistent with the hypothesis of cumulative-particle production as a result of the successive interactions of the incident particle with the single centers along its trajectory in a nucleus.

The correlation function of two protons emitted at angles {theta}{sub lab} near 90{degree} with momenta 315--725 MeV/{ital c} in the reaction {ital pA}{r arrow}{ital ppX} at momentum 7.5 GeV/{ital c} has been investigated as a function of the separation angle and momenta of the secondary protons. The measurements were made in the nuclei C, Ti, and Pb.