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.
21268625
Search for signals from Cygnus X-3 at energies above 50 TeV.
Upper limits for the time-averaged flux of air showers from the direction of Cygnus X-3 during the calendar period 2 April 1986 to 3 May 1987 are found to be 1.5 x 10/sup -13/ cm/sup -2/ sec/sup -1/ for all events, and 7.6 x 10/sup -14/ cm/sup -2/ sec/sup -1/ for events with no observed muons in a 44-m/sup 2/ muon detector. These are integral fluxes above 50 TeV on the assumption of an E/sup -1/ primary spectrum. A possible observation of a short-term signal from Cygnus X-3, with an anomalous muon content, phase correlated with the 4.8-h orbital period, with an integral flux above 50 TeV of (8.2 +- 2.0) x 10/sup -13/ cm/sup -2/ sec/sup -1/ is also reported.
331919
Monte Carlo code G3sim for simulation of plastic scintillator detectors with wavelength shifter fiber readout.
A detailed description of a compact Monte Carlo simulation code "G3sim" for studying the performance of a plastic scintillator detector with wavelength shifter (WLS) fiber readout is presented. G3sim was developed for optimizing the design of new scintillator detectors used in the GRAPES-3 extensive air shower experiment. Propagation of the blue photons produced by the passage of relativistic charged particles in the scintillator is treated by incorporating the absorption, total internal, and diffuse reflections. Capture of blue photons by the WLS fibers and subsequent re-emission of longer wavelength green photons is appropriately treated. The trapping and propagation of green photons inside the WLS fiber is treated using the laws of optics for meridional and skew rays. Propagation time of each photon is taken into account for the generation of the electrical signal at the photomultiplier. A comparison of the results from G3sim with the performance of a prototype scintillator detector showed an excellent agreement between the simulated and measured properties. The simulation results can be parametrized in terms of exponential functions providing a deeper insight into the functioning of these versatile detectors. G3sim can be used to aid the design and optimize the performance of scintillator detectors prior to actual fabrication that may result in a considerable saving of time, labor, and money spent.
124703371
FEL ACTIVITIES IN INDIA
We are building a Compact Ultrafast TErahertz FreeElectron Laser (CUTE-FEL), designed to lase from 50 – 100 μm. The FEL will be driven by a 10-15 MeV electron beam from a Plane-Wave Transformer (PWT) linac. The undulator is a 5 cm period, 2.5 m long PPM planar undulator. We present details of the FEL design and the present status of activities. We also present very preliminary plans for a short-wavelength SASE FEL in India.
30676639
Ultrahigh-energy pulsed emission from Hercules X-1 with anomalous air-shower muon production.
A search for bursts of air-shower events from Hercules X-1 at energies above 50 TeV during the calendar period 2 April 1986 to 5 July 1987 yielded two significant bursts, both occurring on UT 24 July 1986. The events during these bursts were pulsed with a period of 1.235 68 s, significantly different from estimates of the contemporaneous x-ray period. The probability that this represents random statistical fluctuations of the background is estimated to be 2 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}5}$. The muon content of the burst events is anomalous when compared with expectations from $\ensuremath{\gamma}$-ray showers.
13571448
Apparent and Actual Shifts in Mass and Width of ϕ Mesons Produced in Heavy-Ion Collisions
We present a method of analyzing invariant-mass spectra of kaon pairs resulting from decay of ϕ mesons produced in high-energy heavy-ion collisions. It can be used to extract the shifts in the mass and the width (ΔM and ΔΓ) of the ϕ mesons when they are inside the dense matter formed in these collisions. We illustrate our method with the help of available preliminary data. Extracted values of ΔM and ΔΓ are significantly larger than those obtained with an earlier method. Our results are consistent with the experimentally observed pT dependence of the mass shift. Finally, we present a phenomenological relation between ΔM and ΔΓ. It provides a useful constraint on theories which predict the values of these two quantities.
16308546
First Order Phase Transition in Intermediate-Energy Heavy Ion Collisions
We model the disassembly of an excited nuclear system formed as a result of a heavy ion collision. We find that, as the beam energy in central collisions in varied, the dissociating system crosses a liquid-gas coexistence curve, resulting in a first-order phase transition. Accessible experimental signatures are identified: a peak in specific heat, a power-law yield for composites, and a maximum in the second moment of the yield distribution.
16059029
Coalescence, percolation and nuclear multifragmentation
Abstract We show that the coalescence model for fragment formation leads to an approximate site percolation model. Features characteristic of a percolation model also appear in microscopic models of disassembly.
122166973
The phase diagram of QCD: methods and logic of the comparison of experiments and theory
Abstract A small review of the phase diagram of QCD is presented. This is followed by a discussion of the conditions under which experimental data on the fluctuations of conserved quantities in heavy-ion collisions can be treated in the grand canonical ensemble. A robust method for detecting the presence of a nearby critical point in experiments is given. There is a short discussion of the need for non-Gaussian error analysis.
126118861
FINITE SIZE SCALING ON THE ISING COEXISTENCE LINE
We report tests of finite-size scaling ansatzes in the low temperature phase of the two-dimensional Ising model. For moments of the magnetisation density, we find good agreement with the new ansatz of Borgs and Kotecký, and clear evidence of violations of the double Gaussian ansatz. We note that certain consequences of the convexity of the free energy are not adequately treated in either of these approaches.
119300069
Parallel hybrid textures of lepton mass matrices
We analyse the parallel hybrid texture structures in the charged lepton and the neutrino sector. These parallel hybrid texture structures have physical implications as they cannot be obtained from arbitrary lepton mass matrices through weak basis transformations. The total sixty parallel hybrid texture structures can be grouped into twelve classes, and all the hybrid textures in the same class have identical physical implications. We examine all the twelve classes under the assumption of non-factorizable phases in the neutrino mass matrix. Five out of the total twelve classes are found to be phenomenologically disallowed. We study the phenomenological implications of the allowed classes for 1-3 mixing angle, Majorana and Dirac-type CP violating phases. Interesting constraints on effective Majorana mass are obtained for all the allowed classes.