122744149
The colour-singlet technipion P0 and the recent experimental results at LEPII
We study the contributions of the technipion P0 predicted by the technicolour theory to the process e+e-→Zb. Our results show that the production cross section σ is very small. The value of the cross section σ is smaller than 3×10-3 fb for most technicolour models. It is impossible for the recent experimental results at LEPII to be explained within the framework of technicolour theory.
119223958
Suggestion for measuring the weak dipole moment of τ lepton at Z factory
Three new observables for Z-factory to measure the weak dipole moment of $\tau$ lepton ($d_w^\tau$) are proposed. As those observables employed at LEP-I, the new observables depend on the real and imaginary parts of $d_w^\tau$ linearly, thus we calculate the slopes, i.e. the linear coefficients of the dependence, precisely and find that the obtained slopes are much lager than those employed at LEP-I. It means that the signal for the weak dipole moment $d_w^\tau$ may be enhanced quite a lot, if one employs the new observables. Being superior to those at LEP-I, we recommend measuring the weak dipole moment $d_w^\tau$ in terms of the new observables if re-analyzing the data of LEP-I or doing the measurement at a possible Z-factory in the near future.
17399206
Production and decay of the neutral top pion in high-energy e+ e- colliders
We study the production and decay of the neutral top-pion � 0 predicted by topcolor-assisted technicolor(TC2) theory. Our results show that, except the dominant decay modes b ¯, ¯ and gg, the � 0 t can also decay into and Z modes. It can be significantly produced at high energy e + e collider(LC) experiments via the processes e + e → � 0 and e + e → Z� 0 t. We further calculate the production cross sections of the processes e + e → � 0 → ¯ and e + e → Z� 0 → Z¯ tc. We find that the signatures of the neutral top-pion � 0 can be detected via these processes.
118629276
Longitudinal polarization of hyperons in the forward region in polarized pp collisions
We study the longitudinal polarization of hyperons and antihyperons at forward pseudorapidity, $2.5l\ensuremath{\eta}l4$, in singly polarized $pp$ collisions at Relativistic Heavy Ion Collider energies by using different parametrizations of the polarized parton densities and different models for the polarized fragmentation functions. The results show that the ${\ensuremath{\Sigma}}^{+}$ polarization is able to distinguish different pictures on spin transfer in high energy fragmentation processes; and the polarization of $\ensuremath{\Lambda}$ and $\overline{\ensuremath{\Lambda}}$ hyperons can provide sensitivity to the helicity distribution of strange sea quarks. The influence from beam remnant to hyperon polarization in the forward region is also discussed.
118496275
Longitudinal polarization of hyperon and antihyperon in semi-inclusive deep-inelastic scattering
We make a detailed study of the longitudinal polarization of hyperons and antihyperons in semi-inclusive deep-inelastic lepton-nucleon scattering. We present the numerical results for spin transfer in quark fragmentation processes, and analyze the possible origins for a difference between the polarization for hyperon and that for the corresponding antihyperon. We present the results obtained in the case that there is no asymmetry between sea and antisea distribution in the nucleon as well as those obtained when such an asymmetry is taken into account. We compare the results with the available data such as those from COMPASS and make predictions for future experiments including those at even higher energies such as at eRHIC.
15963183
Hyperon polarization in e^-p -->e^-HK with polarized electron beams
We apply the picture proposed in a recent Letter for transverse hyperon polarization in unpolarized hadron-hadron collisions to the exclusive process e − e − nπ + with longitudinally polarized electron beams. We present the predictions for the longitudinal polarizations of the hyperons or neutron in these reactions, which can be used as further tests of the picture.