• Saurabh D Rindani

Articles written in Pramana – Journal of Physics

• Width effects of theZ resonance and CP-violating asymmetry ine+e annihilation

CP-violating rate asymmetry can be generated in a process only if its amplitude possesses an absorptive part. It is pointed out that such an absorptive part can be provided ine+e annihilation by the presence of aZ(Z′) resonance of non-zero width. The CP asymmetry in the process$$e^ + e^ - \to l_i \bar l\left( {l_i \bar l_j } \right)$$, whereli are charged leptons, is discussed in several models. In a specific two-Z model, large and observable CP asymmetry ine+eτ+e (τe+) is shown to be possible at LEP/SLC energies.

• CP violation at colliders

The prospects of experimental detection ofCP violation ate+e and$$pp/p\bar p$$ colliders are reviewed. After a general discussion on the quantities which can measureCP violation and on the implications of theCPT theorem, various possibilities of measuringCP violation arising outside the standard model are taken up.CP violation in leptonic processes, especially polarization effects ine+el+l are discussed next.CP violation in$$t\overline t$$ andW+W production and decay is also described.

• Effect of anomalous tbW vertex on decay-lepton distributions in e+ett and CP-violating asymmetries

We obtain analytic expressions for the energy and polar-angle double differential distributions of a secondary lepton l+ (l) arising from the decay of t(t) in e+ett with an anomalous tbW decay vertex. We also obtain analytic expressions for the various differential cross-sections with the lepton energy integrated over. In this case, we find that the angular distributions of the secondary lepton do not depend on the anomalous coupling in the decay, regardless of possible anomalous couplings occurring in the production amplitude for e+ett. Our study includes the effect of longitudinal e and e+ beam polarization. We also study the lepton energy and beam polarization dependence of certain CP-violating lepton angular asymmetries arising from an anomalous tbW decay vertex and compare them with the asymmetries arising due to CP-violation in the production process due to the top electric or weak dipole moment.

• QCD corrections to decay-lepton polar and azimuthal angular distributions in e+et$$\overline t$$ in the soft-gluon approximationin the soft-gluon approximation

QCD corrections to order αs in the soft-gluon approximation to angular distributions of decay charged leptons in the process e+et$$\overline t$$, followed by semileptonic decay of t$$\overline t$$, are obtained in the esu− e centre-of-mass frame. As compared to distributions in the top rest frame, these have the advantage that they would allow direct comparison with experiment without the need to reconstruct the top rest frame. The results also do not depend on the choice of a spin quantization axis for t or t. Analytic expression for the triple distribution in the polar angle of t and polar and azimuthal angles of the lepton is obtained. Analytic expression is also derived for the distribution in the charged-lepton polar angle. Numerical values are discussed for √s=400, 800 and 1500 GeV.

• Physics prospects at a linear e+e collider

The talk described the prospects of studying standard model parameters as well as scenarios beyond the standard model, like the minimal supersymmetric standard model, theories with extra dimensions and theories with extra neutral gauge bosons, at a future linear e+e collider.

• Working group report: Collider Physics

This is summary of the activities of the working group on collider physics in the IXth Workshop on High Energy Physics Phenomenology (WHEPP-9) held at the Institute of Physics, Bhubaneswar, India in January 2006. Some of the work subsequently done on these problems by the subgroups formed during the workshop is included in this report.

• # Pramana – Journal of Physics

Volume 95, 2021
All articles
Continuous Article Publishing mode

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019