相关论文: Spin effects in diffractive charmonia production
Recent e+e- annihilation experiments show a striking spin alignment of vector mesons produced in the fragmentation of a polarized quark.We show that these data imply a simple relation between the polarization of the anti-quark, which is…
We consider a measurement of exclusive production of scalar $\chi_{c}(0^{++})$ meson in the proton-proton collisions at LHC and RHIC and in the proton-antiproton collisions at the Tevatron via $\chi_{c0} \to \pi^{+}\pi^{-}$ decay. The…
We propose the measurement of $\chi_{cJ}$ polarizations at high energy hadron colliders to study heavy quarkonium production mechanism. We find that the color-singlet model in the $k_t$ factorization approach predicts very different…
Azimuthal asymmetry of vector-meson production in single-transversely polarized proton-proton collisions ($p\up p$) is calculated in the string model of particle production. The asymmetry is generated only during fragmentation of a…
We study spontaneous spin-polarizations of quark matter with flavour $SU(2)$ symmetry at zero temperature in the NJL model. In a relativistic framework, there are two types of the spin-spin interactions: axial-vector (AV) and tensor (T),…
The production of $W^{\pm}$ and $Z^0$ bosons in collisions of longitudinally polarized protons allows to access various combinations of the polarized quark distributions from the study of double and single spin asymmetries. We compute the…
The process of two pion production in the electron-polarized proton scattering is investigated. In the Weizs\"acker-Williams approximation the differential spectral distributions and the spin-momentum correlations are considered. The spin…
In the framework of the $k_T$-factorization approach, the production of Upsilon mesons at the Fermilab Tevatron is considered, and the comparisions of calculated $p_T$-distributions and spin alignment parameter $\alpha$ with the D0…
We discuss central exclusive diffractive dihadron production in proton-proton collisions at high energies. The calculation is based on a tensor pomeron model and the amplitudes for the processes are formulated in an effective…
We show that the cross section of the diffractive production of $b \bar b$ can be described as the sum of two contributions: the first is proportional to the probability of finding a small size $b \bar b$ color dipole in the fast hadron…
We study the fragmentation of a transversely polarized quark into a non collinear (k_T not= 0) spinless hadron and the fragmentation of an unpolarized quark into a non collinear transversely polarized spin 1/2 baryon. These nonperturbative…
The chiral quark model combined with unitarity and impact parameter picture provides simple semiclassical mechanism for generation of the single-spin asymmetry $A_N$ in the $\pi^0$-production in the polarized proton collisions at RHIC. We…
We present a study of the central exclusive production of the $K^{+} K^{-}$ pairs in proton-proton collisions at high energies. We consider diffractive mechanisms including the $K^{+} K^{-}$ continuum, the dominant scalar $f_{0}(980)$,…
We examine the spin-dependence of b-quark production at large transverse momentum in polarized proton-proton collisions. The leading-order (LO) 2 -> 2 subprocesses, g + g -> Q + Q-bar and q+ q-bar -> Q + Q-bar have a large `analyzing…
We derive, in model independent way, the spin structure of the matrix element for the reaction of associative $\Theta^+$ pentaquark production, $\pi^{\pm}+D\to \Theta^+ +\Sigma^{\pm}, $ in the threshold region and in collinear kinematics.…
A phenomenological description of single transverse spin effects in hadron-hadron inclusive processes is proposed, assuming a generalized factorization scheme and pQCD hard interactions. The transverse momentum, k_T, of the quarks inside…
Measurements of polarized neutron scattering were performed on a $S=1/2$ chain multiferroic LiCu$_2$O$_2$. In the ferroelectric ground state with the spontaneous polarization along the c-axis, the existence of transverse spiral spin…
We study the production of charginos e^+ e^- -> chi^+_i chi^-_j, (i,j=1,2) with polarized beams and the subsequent decays chi^+_i -> chi^0_k ell^+ nu and chi^-_j -> chi^0_l ell^- nu, (k,l=1,...,4), including the complete spin correlations…
We discuss exclusive central diffractive production of $\pi^{+} \pi^{-}$ in proton-(anti)proton collisions at high energies. Based on a tensor pomeron model we present results of the purely diffractive dipion continuum, the scalar…
The azimuthal dependence of hadrons produced in lepton scattering off a polarized hadron probes the quark transverse-spin distributions. In the calculation of the asymmetries, transverse momenta of quarks in the distribution and…