Search for η-mesic nuclei in the SRC/BM@N experiment at the Nuclotron

The SRC/BM@N experiment was carried out in the 55th run of the Nuclotron using a liquid hydrogen target and a carbon beam with a kinetic energy of about 3.1 GeV/n. We propose to analyze the experimental data to search for a quasi-bound state of η-meson and nucleons in the reaction 12C+p → η(A-1)+X → π+p+(A-2). To achieve this goal, it is necessary to identify the residual nucleus (A-2) and the proton-pion pair formed from η-nuclei decay.

An extension of BDK event generator

An extension of the well known ee → 4l event generator of F. A. Berends, P. H. Daverveldt, and R. Kleiss is presented. This extension accounts for production of narrow resonances, as well as the initial state radiation. In addition, it allows one to simulate the production of l+ l−π+π− with the lepton pair and the pion pair in 1−− states.

High Precision Measurement of Transversity Using Di-hadron Correlations in p↑+p Collisions at sNN = 500 GeV

The transversity distribution, which describes transversely polarized quarks in a transversely polarized nucleon, is a fundamental component of the current picture of the spin structure of the nucleon, and is only loosely constrained by existing semi-inclusive deep inelastic scattering data. The di-hadron interference fragmentation function (IFF), which describes the fragmentation of transversely polarized quarks, is expected to give rise to spin-dependent di-hadron correlations in p[Formula: see text]+p collisions. Significant di-hadron correlations have recently been measured at RHIC in p[Formula: see text]+p collisions at [Formula: see text] = 200 GeV at mid-rapidity. In 2011, STAR collected p[Formula: see text]+p data at [Formula: see text] = 500 GeV, allowing STAR to extend these di-hadron asymmetries into a previously unexplored kinematic region. The status of the charge-ordered pion pair asymmetry measurement from [Formula: see text] = 500 GeV p[Formula: see text]+p collisions will be presented.

DETECTING CORRELATED DI-HADRON PAIRS: ABOUT THE EXTRACTION OF TRANSVERSITY AND BEYOND

We summarize the latest achievements about the extraction of the transversity parton distribution based on an analysis of pion-pair production in deep-inelastic scattering off transversely polarized targets in collinear factorization. Recently released data for proton and deuteron targets by HERMES and COMPASS allow for a flavor separation of the valence components of transversity. This extraction relies on di-hadron fragmentation functions. The latter have been taken from the first recent analysis of the semi-inclusive production of two pion pairs in back-to-back jets in e+e- annihilation. We also comment on the possibility of isolating new azimuthally asymmetric correlations of opposite pion pairs, which could arise when a fragmenting quark crosses parity-odd domains localized in Minkowski space-time and induced by the topologically nontrivial QCD background (the so-called θ vacuum).