• Pankaj Jain

Articles written in Pramana – Journal of Physics

• Exclusive hadronic processes and color transparency

We review the current status of high energy exclusive processes and color transparency.

• The proton electromagnetic form factorF2 and quark orbital angular momentum

We analyse the proton electromagnetic form factor ratioR(Q2) =QF2(Q2)/F1(Q2) as a function of momentum transferQ2 within perturbative QCD. We find that the prediction for (R(Q2) at large momentum transferQ depends on the exclusive quark wave functions, which are unknown. For a wide range of wave functions we find thatQF2F1 ∼ const. at large momentum transfer, which is in agreement with recent JLAB data.

• Pseudoscalar-photon mixing and the large scale alignment of QSO optical polarizations

We review the observation of large scale alignment of QSO optical polarizations. Alignment is seen in patches of distance scale of order 1 Gpc. We argue that the existence of a hypothetical light pseudoscalar can explain these observations.

• Proton electromagnetic form factors at large momentum transfer

We review the current experimental and theoretical status of the proton electromagnetic form factors.

• The dynamical mixing of light and pseudoscalar ¯elds

We solve the general problem of mixing of electromagnetic and scalar or pseudoscalar fields coupled by axion-type interactions $L_{\text{int}} = g_{\phi}\phi \epsilon_{\mu \nu \alpha \beta} F^{\mu \nu} F^{\alpha \beta}$. The problem depends on several dimensionful scales, including the magnitude and direction of background magnetic field, the pseudoscalar mass, plasma frequency, propagation frequency, wave number, and finally the pseudoscalar coupling. We apply the results to the first consistent calculations of the mixing of light propagating in a background magnetic field of varying directions, which show a great variety of fascinating resonant and polarization effects.

• # Pramana – Journal of Physics

Volume 94, 2020
All articles
Continuous Article Publishing mode

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019