arXiv subjects

Chun-xiu Liu

Publications and source records attributed to Chun-xiu Liu.

7 recordsLinked to original sources

arXiv2002

Hyperon polarization in ν_μcharged current interaction at the NOMAD energies

We show that, in $ν_μN\to μ^-ΛX$ at the NOMAD energies, it is impossible to separate the products of the fragmentation of the struck quark from those of the nucleon remnant. The latter has a large contribution even in the current fragmentation region and has to be taken into account in calculating $Λ$ polarization using different pictures. Based on this, we make a rough estimation for the longitudinal $Λ$ polarization in $ν_μ N \to μ^- ΛX$ at the NOMAD energies. A comparison with the data is given and predictions for $ν_μN\toμ^-Σ^+X$ are presented.

hep-ph↗

arXiv2002

Longitudinal polarization of hyperons in high $p_\perp$ jets in singly polarized pp collisions at high energies

We calculate the longitudinal polarizations of hyperons in high $p_\perp$ jets in $pp$ collisions in which one of the protons is longitudinally polarized at RHIC energies using different models for the spin transfer in fragmentation process. The results show that the measurements of these polarizations can be used to study the spin transfer in high energy fragmentation processes in general and to test the different models in particular. Our results show especially that the magnitude of the polarization of $Λ$ is rather small whereas that of $Σ^+$ is considerably larger in the large rapidity region. The differences between the results from different pictures for $Σ^+$ polarizations is also much larger. Hence, the measurement of $Σ^+$ polarization should be more effective to distinguish between different models especially the SU(6) or the DIS picture for spin transfer in fragmentation processes.

hep-ph↗

arXiv2001

Hyperon polarization in semi-inclusive deeply inelastic lepton-nucleon scattering at high energy

We calculate the polarizations for different octet hyperons produced in the current fragmentation regions of the deeply inelastic lepton-nucleon scatterings $μ^-N \to μ^- HX$ and $ν_μ N \to μ^- HX$ at high energy using different models for spin transfer in fragmentation processes. The results show that measurements of those hyperon polarizations should provide useful information to distinguish between different models in particular the SU(6) and the DIS pictures used frequently in the literature. We found, in particular, that measuring the polarization of $Σ^+$ produced in these processes can give a better test to the validity of the different spin transfer models.

hep-ph↗

arXiv2001

Spin transfer in high energy fragmentation processes

We point out that measuring longitudinal polarizations of different hyperons produced in lepton induced reactions are ideal to study the spin transfer of the fragtmenting quark to produced hadron in high energy hadronization processes. We briefly summarize the method used in calculating the hyperon polarizations in these processes, then present some of the results for e+e- and e-p or νp reactions obtained using two different pictures for the spin structure of hyperon: that drawn from polarized deep inelastic lepton-nucleon scattering data or that using SU(6) symmetric wave functions. The results show in particular that measurements of such polarizations should provide useful information to the question of which picture is more suitable in describing the spin effects in the fragmentation processes.

hep-ph↗

arXiv2001

Spin alignment of vector meson in e+e- annihilation at Z0 pole

We calculate the spin density matrix of the vector meson produced in e+e- annihilation at Z^0 pole. We show that the data imply a significant polarization for the antiquark which is created in the fragmentation process of the polarized initial quark and combines with the fragmenting quark to form the vector meson. The direction of polarization is opposite to that of the fragmenting quark and the magnitude is of the order of 0.5. A qualitative explanation of this result based on the LUND string fragmentation model is given.

hep-ph↗

arXiv2001

Energy Dependence of the Contribution of Pion Exchange to Large-Rapidity-Gap Events in Deep Inelastic Scattering

We study the energy dependence of the contribution of pion exchange to large-rapidity-gap events in deep inelastic scattering. The results show that this contribution can be quite significant at low energy and that the LRG events observed by E665 collaboration in μXe and μD interactions at 490 $GeV$ can be reasonably well described in terms of meson exchange. We also show that the distribution of the maximum rapidity for all hadrons is quite different from that for charged hadrons only and that the former exhibits also shoulder-like structure for events at 490 $GeV$ similar to that at HERA.

hep-ph↗

arXiv2000

Spin structure and longitudinal polarization of hyperon in e+e- annihilation at high energies

Longitudinal polarizations of different kinds of hyperons produced in e+e- annihilation at LEP I and LEP II energies in different event samples are calculated using two different pictures for the spin structure of hyperon: that drawn from polarized deep inelastic lepton-nucleon scattering data or that using SU(6) symmetric wave functions. The result shows that measurements of such polarizations should provide useful information to the question of which picture is more suitable in describing the spin effects in the fragmentation processes.

hep-ph↗