Farrukh Chishtie

Spin effects in the pion holographic light-front wavefunction

We account for dynamical spin effects in the holographic light-front wavefunction of the pion in order to predict its mean charge radius, decay constant, spacelike electromagnetic form factor, twist-2 Distribution Amplitude and the photon-to-pion transition form factor. Using a universal fundamental AdS/QCD scale of 523 MeV and a constituent quark mass of 330 MeV, we find a remarkable improvement in describing all observables.

Asymptotic Padé-approximant predictions for renormalization-group functions of massive φ4 scalar field theory

Abstract Within the context of massive N -component φ 4 scalar field theory, we use asymptotic Pade-approximant methods to estimate from prior orders of perturbation theory the five-loop contributions to the coupling-constant β -function β g , the anomalous mass dimension γ m , the vacuum-energy β -function β v , and the anomalous dimension γ 2 of the scalar field propagator. These estimates are then compared with explicit calculations of the five-loop contributions to β g , γ m , β v , and are seen to be respectively within 5%, 18%, and 27% of their true values for N between 1 and 5. We then extend asymptotic Pade-approximant methods to predict the presently unknown six-loop contributions to β g , γ m , and β v . These predictions, as well as the six-loop prediction for γ 2 , provide a test of asymptotic Pade-approximant methods against future calculations.

The gravitational wave pulsar signal with jovian and lunar perturbations and orbital eccentricity corrections

In this work, we present the analytic treatment of the Fourier transform (FT) of the gravitational wave (GW) signal from a pulsar in a parametrized model discussed by Brady et al (1998 Phys. Rev. D 57 2101). The formalism lends itself to a development of the FT that accounts for the corrections due to the orbital eccentricity, and the Jovian and lunar perturbations in terms of well-known special functions.

ISOSPIN SYMMETRY BREAKING IN B → K*γ DECAY DUE TO AN EXTRA GENERATION OF VECTOR QUARKS

The extra contributions due to an extra generation of vector-like quarks to the isospin symmetry breaking observable associated with the radiative B → K*γ decay is obtained. It is shown that this additional contribution is sensitive to the nonunitarity parameter Usb, which is a measure of the the strength of the non-zero tree-level flavor changing neutral current in this model. The significance of this result is that, once accurate experimental results on the isospin asymmetry becomes available, one can constrain the Usb independent of the mass of the extra quarks and so a much more stringent acceptable model parameter space could be obtained.

Phronesis and the Practice of Science

Originally coined by Aristotle, and concerned with context, ethics, particulars, and practical rationality, phronesis is a rich concept. From the text Nicomachean Ethics (Aristotle, trans. 1976), it is usually translated as practical wisdom or prudence, a virtue related to moral thought.

Path integral quantization of the first order Einstein–Hilbert action from its canonical structure

We consider the form of the path integral that follows from canonical quantization and apply it to the first order form of the Einstein–Hilbert action in d > 2 dimensions. We show that this is inequivalent to what is obtained from applying the Faddeev–Popov (FP) procedure directly. Due to the presence of tertiary first class constraints, the measure of the path integral is found to have a substantially different structure from what arises in the FP approach. In addition, the presence of second class constraints leads to non-trivial ghosts, which cannot be absorbed into the normalization of the path integral. The measure of the path integral lacks manifest covariance.

SUMMING RADIATIVE CORRECTIONS TO THE EFFECTIVE POTENTIAL

When one uses the Coleman–Weinberg renormalization condition, the effective potential V in the massless

A study of the gravitational wave form from pulsars

\phi_4^4

Renormalization-scale invariance, minimal sensitivity, and the inclusive hadronic decays of a 115 GeV Higgs particle

theory with O(N) symmetry is completely determined by the renormalization group functions. It has been shown how the (p + 1) order renormalization group function determine the sum of all the NpLL order contribution to V to all orders in the loop expansion. We discuss here how, in addition to fixing the NpLL contribution to V, the (p + 1) order renormalization group functions can also be used to determine portions of the Np+nLL contributions to V. When these contributions are summed to all orders, the singularity structure of V is altered. An alternate rearrangement of the contributions to V in powers of ln ϕ, when the extremum condition V′(ϕ = v) = 0 is combined with the renormalization group equation, show that either v = 0 or V is independent of ϕ. This conclusion is supported by showing the LL, …, N4LL contributions to V become progressively less dependent on ϕ.

Renormalization Scheme Dependence in a QCD Cross Section

We present analytical and numerical studies of the Fourier transform (FT) of the gravitational wave (GW) signal from a pulsar, taking into account the rotation and orbital motion of the Earth. We also briefly discuss the Zak– Gelfand integral transform and a special class of the generalized hypergeometric function of potential relevance. The Zak–Gelfand integral transform that arises in our analytic approach has also been useful for Schr¨ odinger operators in periodic potentials in condensed matter physics (Bloch wavefunctions) and holds promise for the study of periodic GW signals for long integration times.