On use of ghost-less beam splitter in reversal shear interferometer for measurement of spatial coherence of large cross-section laser beam

A configuration of reversal shear interferometer suitable for measurement of spatial coherence of high average power, large cross-section laser beam has been discussed. Ghost-less beam splitters in which unwanted multiple reflections from the surfaces have been suppressed by total internal reflection are used for beam splitting and re-combination. Advantages and drawbacks of this configuration have been discussed.     

Atom Capture by Nanotube and Scaling Anomaly

The existence of bound state of the polarizable neutral atom in the inverse square potential created by the electric field of a single walled charged carbon nanotube (SWNT) is shown to be theoretically possible. The consideration of inequivalent boundary conditions due to self-adjoint extensions lead to this nontrivial bound state solution. It is also shown that the scaling anomaly is responsible for the existence of such bound state. Binding of the polarizable atoms in the coupling constant interval η ²∈[0,1) may be responsible for the smearing of the edge of steps in quantized conductance, which has not been considered so far in the literature.     

Asymptotic bounds on pion form factor

A technique recently developed for inelastic electron proton scattering is applied for inelastic electron pion scattering. It is found that all the derivatives of off-shell form factor of pion nears=m _π ² and for largeQ ² are bounded from above, provided that the dispersion relation for the form factor requires no more than one subtraction. The elastic pion form factor is bounded by [lnQ ²] ^c /Q ², wherec is any positive constant.     

Anisotropic spin—lattice relaxation in the triplet state of naphtralene-h8 in n-pentane

The temperature dependence of the individual spin—lattice relaxation rate constants (W_ij) between the lowest triplet sublevels of naphthalene-h₈ in a polycrystalline Shpol'skii matrix of n-pentane have been measured between 1.2 and 2.4 K in zero field. The total sublevel decay constants are evaluated and found to be independent of temperature. The W_ij are found to be highly anisotropic, but the anisotropy pattern differs from that observed previously in a durene matrix.     

Weak radiative decay Λ b →Λγ in the heavy quark effective theory

The weak radiative decay Λ _b →Λγ is studied in the heavy quark effective theory treatings-quark as heavy. This rare decay is induced by the short distance electromagnetic penguins. Including corrections of the order of (1/m _Q), we obtain the transition matrix element and the corresponding decay width. The Isgur-Wise function is evaluated in the largeN _c limit and the branching ratio obtained is 1.48×10⁻⁵.     

Flavour physics and CP violation

It is well known that the study of flavour physics and CP violation is very important to critically test the Standard Model and to look for possible signature of new physics beyond it. The observation of CP violation in kaon system in 1964 has ignited a lot of experimental and theoretical efforts to understand its origin and to look for CP violation effects in other systems besides the neutral kaons. The two B-factories BABAR and BELLE, along with other experiments, in the last decade or so made studies in flavour physics and CP violation a very interesting one. In this article we discuss the status and prospectives of the flavour physics associated with the strange, charm and bottom sectors of the Standard Model. The important results in kaon sector will be briefly discussed. Recently, mixing in the charm system has been observed, which was being pursued for quite some time without any success. The smallness of the mixing parameters in the charm system is due to the hierarchical structure of the CKM matrix. Interestingly, so far we have not found CP violation in the charm system but in the future, with more dedicated experiments at charm threshold, the situation could change. Many interesting observations have been made in the case of bottom mesons and some of them show some kind of deviations from that of the Standard Model expectations which are mainly associated with the b → s flavour changing neutral current transitions. It is long believed that the B _s system could be the harbinger of new physics since it is a system in which both bottom and strange quarks are the constituents. Recently, D0 and CDF announced their result for the B _s mixing which is claimed to be the first possible new physics signature in the flavour sector. We plan to touch upon all important issues pointing out both theoretical and experimental developments and future prospects in this review article.     

Inequivalent Quantization in the Field of a Ferromagnetic Wire

We argue that it is possible to bind neutral atom (NA) to the ferromagnetic wire (FW) by inequivalent quantization of the Hamiltonian. We follow the well known von Neumann’s method of self-adjoint extensions (SAE) to get this inequivalent quantization, which is characterized by a parameter Σ∈ℝ(mod2π). There exists a single bound state for the coupling constant η ²∈[0,1). Although this bound state should not occur due to the existence of classical scale symmetry in the problem. But since quantization procedure breaks this classical symmetry, bound state comes out as a scale in the problem leading to scaling anomaly. We also discuss the strong coupling region η ²<0, which supports bound state making the problem re-normalizable.     

Lewis acid-catalyzed one-pot, three-component route to chiral 3,3'-bipyrroles

3,3'-Bipyrroles 3 could be synthesized using a double Michael addition reaction involving diaroyl acetylene 1 and the appropriate 1,3-dicarbonyls 2 using ammonium acetate as a nitrogen source. The axial chirality of bipyrrole was anticipated from the X-ray crystal structure and DFT calculations and confirmed by separating the racemates on a chiral column and subsequent CD spectra of the enantiomers. The absolute configuration of the enantiomers was achieved by theoretical CD spectra calculation using the ZINDO method.