119964333
Magnetic and quadrupole moments of the W boson
The validity of the external-field treatment for the electromagnetic scattering of a W boson in the Weinberg model is examined, and calculation of the magnetic and quadrupole moments of the W boson is carried out in the renormalizable gauge instead of the unitary gauge used by earlier authors. Our results agree with those of Bardeen, Gastmans, and Lautrup in the static approximation, and thus gauge independence of these results is demonstrated. (AIP)
120383870
Higgs model with ghost-field formalism
The Higgs model for the interaction of vector and scalar fields is treated by means of the ghost-field formalism, which preserves the unitarity of the scattering operator as well as simplifies the renormalization procedure. Our ghost-field formalism has some similarity to the ${R}_{\ensuremath{\xi}}$ formalism with $\ensuremath{\xi}=1$, but it does not require the introduction of the so-called gauge-compensating terms. Applications to the second-order self-energy of a scalar particle and to the fourth-order scattering of vector particles are discussed.
122156675
Relativistic Hadron Model with Intrinsic Mass Splittings
A simple mechanism for the $\mathrm{SU}(3)$-symmetry breaking in strong interactions is introduced by using the formalism of the multispinor field equations, which avoids the use of physical quarks but has resemblance to the quark model. The resulting treatment leads to the Gell-Mann-Okubo mass formula for baryons, but not for mesons. It yields approximate values of -19.5\ifmmode^\circ\else\textdegree\fi{} and 33\ifmmode^\circ\else\textdegree\fi{} for the $\ensuremath{\eta}\ensuremath{-}{\ensuremath{\eta}}^{\ensuremath{'}}$ and $\ensuremath{\varphi}\ensuremath{-}\ensuremath{\omega}$ mixing angles, respectively, and also provides a reasonable explanation for the intermultiplet meson mass formula $m_{K}^{}{}_{}{}^{2}\ensuremath{-}m_{\ensuremath{\pi}}^{}{}_{}{}^{2}=m_{{K}^{*}}^{}{}_{}{}^{2}\ensuremath{-}m_{\ensuremath{\rho}}^{}{}_{}{}^{2}$.
121663425
Quantum-chromodynamic potential model for light and heavy quarkonia
Our earlier treatment for the investigation of the cc-bar, bb-bar, and tt-bar spectra is extended to other p quarkonia with u, d, s, c, and b quarks. We find that it is possible to account fully for the observed ground-state hyperfine splittings of light as well as heavy quarkonia provided that the perturbative quantum-chromodynamic potential is supplemented not only by the nonperturbative confining potential but also by a nonperturbative annihilation potential which rapidly decreases with increase in the quark mass. We also give our predictions for the experimentally interesting bu-bar, bs-bar, and bc-bar systems with unknown mass splittings.
122167852
MULTIPLE PHOTON PRODUCTION IN QUANTUM ELECTRODYNAMICS
Multiple production of photons in high-energy processes in quantum electrodynamics is investigated, and the electron-positron annihilation is specially discussed in detail. It is found that at very high energies in cosmic rays, multiple production of up to four or five observable photons can easily take place. But, the probability, according to quantum electrodynamics, for the multiple production of a larger number of observable photons is quite small.
6552264
Nonsingular potential model for heavy quarkonia.
A nonsingular potential model for heavy quarkonia is described which does not require recourse to an illegitimate perturbative treatment for the investigation of quarkonium spectra. Our overall results for the energy levels, the leptonic widths, and the E1 transition widths are in very good agreement with the experimental data for bb-bar and they are reasonably good for cc-bar. We also find that the confining part of the quarkonium potential is scalar-vector exchange rather than the currently favored scalar exchange.
119030036
Grand canonical model predictions for nuclear fragmentation
The grand canonical ensemble has been used to make predictions for composite yields using simple models for nuclear fragmentation. While this gives correct model prediction for high energy collisions, it can give very inaccurate results at intermediate energy.
120975097
Magnetic moments of light baryons in harmonic model
Abstract Anomalous magnetic moments of light baryons are calculated in a relativistic harmonic oscillator model to obtain good agreement with experiment.
55962889
Solar diurnal anisotropy measured using muons in GRAPES-3 experiment in 2006
The GRAPES-3 experiment at Ooty contains a large-area (560 m2) tracking muon detector. This detector consists of 16 modules, each 35 m2 in area, that are grouped into four supermodules of 140 m2 each. The threshold energy of muons is sec(θ) GeV along a direction with zenith angle θ and the angular resolution of the muon detector is 6°. Typically, it records ~4×109 muons every day. The muon detector has been operating uninterruptedly since 2001, thus providing a high statistics record of the cosmic ray flux as a function of time over one decade. However, prior to using these data, the muon rate has to be corrected for two important atmospheric effects, namely, variations in atmospheric pressure and temperature. Because of the near equatorial location of Ooty (11.4°N), the seasonal variations in the atmospheric temperature are relatively small and shall be ignored here. Due to proximity to the equator, the pressure changes at Ooty display a dominant 12 h periodic behaviour in addition to other seasonal changes. Here, we discuss various aspects of a novel method for accurate pressure measurement and subsequent corrections applied to the GRAPES-3 muon data to correct these pressure-induced variations. The pressure-corrected muon data are used to measure the profile of the solar diurnal anisotropy during 2006. The data, when divided into four segments, display significant variation both in the amplitude (~45%) and phase (~42 m) of the solar diurnal anisotropy during 2006, which was a period of relatively low solar activity.
119328029
Hadron Properties just before Deconfinement
Abstract We have investigated hadron screening masses, the chiral condensate, and the pion decay constant close to the deconfinement phase transition in the confined phase of QCD. The simulations were done in the quenched approximation, on a lattice of size 32 3 × 8. We examined temperatures ranging from 0.75 T c up to 0.92 T c . We see no sign of a temperature dependence in the chiral condensate or the meson properties, but some temperature dependence for the nucleon screening mass is not excluded.
54200433
Status of the CUTE-FEL Project
We are building a Compact Ultrafast Terahertz FreeElectron Laser (CUTE-FEL) designed to lase at around 80 μm. Here we report on the present status. A 2 μs, 40 keV beam from a DC thermionic electron gun has been accelerated up to 4.5 MeV using a 21 cm long, 4-cell, Plane Wave Transformer (PWT) linac. Current measurements using a Fast Current Transformer (FCT) after a bending magnet energy spectrometer show a peak current of about 10 mA at 4.5 MeV. This beam was transported through a 1.25 m long undulator section. We have also built and tested the 476 MHz pre-buncher for the linac, and are in the midst of assembling the final FEL beamline.