Probing space-time structure of new physics with polarized beams at the ILC

At the International Linear Collider large beam polarization of both the electron and positron beams will enhance the signature of physics due to interactions that are beyond the Standard Model. Here we review our recently obtained results on a general model independent method of determining for an arbitary one-particle inclusive state the space-time structure of such new physics through the beam polarization dependence and angular distribution of the final state particle.Comment: 6 pages, plain latex, Talk given at LCWS06, Linear Collider Workshop, 9-13 March 2006, Bangalore, Indi

The Nobel Prize in Physics 2002 for the observation of cosmic neutrinos

A brief description of the work for which the first half of the Nobel prize for physics for the year 2002 is presented.Comment: 2 pages plain latex, to appear in Resonance, Journal of Science Educatio

Fundamental particles and their interactions

In this article the current understanding of fundamental particles and their interactions is presented for the interested non-specialist, by adopting a semi-historical path. A discussion on the unresolved problems is also presented.Comment: 10 pages, plain late

Lectures on Unification

In these lectures we review the motivation, principles of and (circumstantial) evidence for the program of unification of the fundamental forces. In an appendix, we review the group theory pertinent to the program.Comment: 28 pages plain LaTeX, to be run twice. Lectures given at the Sixth ICTP-BCSPIN School on Current Trends in High Energy Physics and Cosmology, Kathmandu, Nepal, May 19-June 3 199

A note on the heat kernel coefficients for nonminimal operators

We consider certain results for the heat kernel of nonminimal operators. The general expressions provided by Gusynin and Kornyak resulting from symbolic computation programmes for n dimensions are evaluated for 4 dimensions which are checked against results given by Barvinsky and Vilkovisky. We also check that the results in flat space are consistent with earlier results of Guendelmen et al. We then consider a powerful construction of the Green function of a nonminimal operator by Shore for covariantly constantly gauge fields in flat spacetime, and employ dimensional arguments to produce a check on the gauge parameter dependence of a certain coefficient. The connection of the results for heat kernel coefficients emanating from the construction of Shore, to those from other techniques is hereby established for the first time.Comment: 9 pages, plain latex, accepted for publication by Journal of Physics

Higher Threshold Parameters in pi pi Scattering

A family of threshold parameters which probe the stability of chiral predictions is considered. The relevant criteria for the choice of threshold parameters are discussed. Sum rules for these quantities are derived from dispersion relations and evaluated from effective range formulae. Good agreement with two-loop chiral estimates for many of these quantities is found and interesting discrepancies are discussed.Comment: 15 pages, LaTe

Helicity-Flip Bremsstrahlung and the Measurement of CP-Violating Form Factors in Polarized e+e−e^+e^- Collisions

Certain momentum correlations in the production and subsequent decay of heavy fermion pairs in $e^+e^-$ collisions have increased sensitivity to CP-violating electric and ``weak" dipole form factors of the fermion in the presence of longitudinal polarization of the $e^+e^-$ beams. However, unless the polarizations of $e^+$ and $e^-$ are equal and opposite, collinear initial-state radiation accompanied by helicity flip results in a CP-invariant contribution to these and acts as a background, and must be calculated and subtracted in order to isolate the CP-violating contribution due to the dipole form factor.We calculate this background contribution to such correlations, to order $\alpha$, in $e^+e^-\rightarrow \tau^+\tau^-$ and $e^+e^-\rightarrow t\bar{t}$. For the anticitipated luminosities at $\tau$-charm factories and SLC, for the $\tau$, and at a future linear collider with centre-of-mass energy of 500 GeV for the top, these backgrounds are smaller than the statistical background and may be safely neglected.Comment: 21 pages plain LaTeX, to be run twic

Inclusive spin-momentum analysis and new physics at a polarized electron-positron collider

We consider the momentum distribution and the polarization of an inclusive heavy fermion in a process assumed to arise from standard-model (SM) $s$-channel exchange of a virtual $\gamma$ or $Z$ with a further contribution from physics beyond the standard model involving $s$-channel exchanges. The interference of the new physics amplitude with the SM $\gamma$ or $Z$ exchange amplitude is expressed entirely in terms of the space-time signature of such new physics. Transverse as well as longitudinal polarizations of the electron and positron beams are taken into account. Similarly, we consider the cases of the polarization of the observed final-state fermion along longitudinal and two transverse spin-quantization axes which are required for a full reconstruction of the spin dependence of the process. We show how these model-independent distributions can be used to deduce some general properties of the nature of the interaction and some of their properties in prior work which made use of spin-momentum correlations.Comment: 32 pages, plain latex, 3 figures produced by axodraw2, 4 tables, sequels to prior publications hep-ph/0601199 and arXiv:0805.2279; v2 corresponds to version accepted for publication in European Physical Journal C, compared to v1, extended discussions, additional figure, clarifying comments, additional reference