Remarks on flavour mixings from orbifold compactification

We consider 5d SU(5) GUT models based on the orbifold $S^1/(Z_2 \times Z_2')$, and study the different possibilities of placing the SU(5) matter multiplets in three possible locations, namely, the two branes at the two orbifold fixed points and SU(5) bulk. We demonstrate that if flavour hierarchies originate solely from geometrical suppressions due to wavefunction normalisation of fields propagating in the bulk, then it is not possible to satisfy even the gross qualitative behaviour of the CKM and MNS matrices regardless of where we place the matter multiplets.Comment: 4 pages, Late

Density functional theory for fermions close to the unitary regime

We consider interacting Fermi systems close to the unitary regime and compute the corrections to the energy density that are due to a large scattering length and a small effective range. Our approach exploits the universality of the density functional and determines the corrections from the analyical results for the harmonically trapped two-body system. The corrections due to the finite scattering length compare well with the result of Monte Carlo simulations. We also apply our results to symmetric neutron matter.Comment: 4 pages, 2 figure

Model study of hot and dense baryonic matter

The properties of baryonic matter have been investigated at finite density and temperature using different models. The variation of baryon masses and fractional number densities with baryon density and temperature obtained from different models have been compared. The quark hadron phase transition have been studied using Chiral Colour Dieletric (CCD) model in the quark sector. No phase transition has been seen for the different variants of the Zimanyi-Moszkowski model. However, a phase transition is observed for the linear and non-linear Walecka model.Comment: Latex, 16 postscript figures available on reques

Local and global statistical distances are equivalent on pure states

The statistical distance between pure quantum states is obtained by finding a measurement that is optimal in a sense defined by Wootters. As such, one may expect that the statistical distance will turn out to be different if the set of possible measurements is restricted in some way. It nonetheless turns out that if the restriction is to local operations and classical communication (LOCC) on any multipartite system, then the statistical distance is the same as it is without restriction, being equal to the angle between the states in Hilbert space.Comment: 5 pages, comments welcom

Flux-density spectral analysis for several pulsars and two newly-identified gigahertz-peaked spectra

In this paper we present results from flux density measurements for 21 pulsars over a wide frequency range, using the Giant Metrewave Radio Telescope (GMRT) and the Effelsberg telescope. Our sample was a set of mostly newly discovered pulsars from the selection of candidates for gigahertz-peaked spectra (GPS) pulsars. Using the results of our observations along with previously published data, we identify two new GPS pulsars. One of them, PSR J1740+1000, with dispersion measure of 24 pc cm$^{-3}$, is the first GPS pulsar with such a low DM value.We also selected several strong candidates for objects with high frequency turnover in their spectra which require further investigation.We also revisit our source selection criteria for future searches for GPS pulsars.Comment: 10 pages, 2 tables, 9 figures, accepted for publication in MNRA

A comparison of ultraviolet sensitivities in universal, nonuniversal, and split extra dimensional models

We discuss the origin of ultraviolet sensitivity in extra dimensional theories, and compare and contrast the cutoff dependences in universal, nonuniversal and split five dimensional models. While the gauge bosons and scalars are in the five dimensional bulk in all scenarios, the locations of the fermions are different in different cases. In the universal model all fermions can travel in the bulk, in the nonuniversal case they are all confined at the brane, while in the split scenario some are in the bulk and some are in the brane. A possible cure from such divergences is also discussed.Comment: 9 pages, Latex, no figure, v2: further clarifications and references added, accepted for publication in Phys. Rev.

Determination of hydrogen permeability in commercial and modified superalloys

The results of hydrogen permeability measurements on several iron- and cobalt-base alloys as well as on two long-ranged ordered alloys over the range of 705 to 870 C (1300 to 1600 F) are summarized. The test alloys included wrought alloys N-155, IN 800, A-286, 19-9DL, and 19-9DL modifications with aluminum, niobium, and misch metal. In addition, XF-818, CRM-6D, SA-F11, and HS-31 were evaluated. Two wrought long-range ordered alloys, Ni3Al and (Fe,Ni)3(V,Al) were also evaluated. All tests were conducted at 20.7 MPa pressure in either pure and/or 1% CO2-doped H2 for test periods as long as 133 h. Detailed analyses were conducted to determine the relative permeability rankings of these alloys and the effect of doping, exit surface oxidation, specimen design variations, and test duration on permeability coefficient, and permeation activation energies were determined. The two long-range ordered alloys had the lowest permeability coefficients in pure H2 when compared with the eight commercial alloys and their modifications. With CO2 doping, significant decrease in permeability was observed in commercial alloys--no doped tests were conducted with the long-range ordered alloys

Lepton Flavours at the Early LHC Experiments as the Footprints of the Dark Matter Producing Mechanisms

The mSUGRA parameter space corresponding to light sleptons well within the reach of LHC and relatively light squarks and gluinos (mass $\le$ 1 TeV) has three regions consistent with the WMAP data on dark matter relic density and direct mass bounds from LEP 2. Each region can lead to distinct leptonic signatures from squark-gluino events during the early LHC experiments (integrated luminosity $\sim 10 ~fb^{-1}$ or even smaller). In the much studied stau-LSP coannihilation region with a vanishing common trilinear coupling ($A_0$) at the GUT scale a large fraction of the final states contain electrons and / or muons and $e$ - $\mu$ - $\tau$ universality holds to a good approximation. In the not so well studied scenarios with non-vanishing $A_0$ both LSP pair annihilation and stau-LSP coannihilation could contribute significantly to the dark matter relic density for even smaller squark-gluino masses. Our simulations indicate that the corresponding signatures are final states rich in $\tau$-leptons while final states with electrons and muons are suppressed leading to a violation of lepton universality. These features may be observed to a lesser extent even in the modified parameter space (with non-zero $A_0$) where the coannihilation process dominates. We also show that the generic $m$-leptons + $n$-jets+ $\not! E_T$ signatures without flavour tagging can also discriminate among the three scenarios. However, the signals become more informative if the $\tau$ and $b$-jet tagging facilities at the LHC experiments are utilized.Comment: 28 page

SUSY darkmatter at the LHC - 7 TeV

We have analysed the early LHC signatures of the minimal supergravity (mSUGRA) model. Our emphasis is on the 7 - $TeV$ run corresponding to an integrated luminosity of $\sim 1.0 ~fb^{-1}$ although we have also discussed briefly the prospects at LHC-10 $TeV$. We focus on the parameter space yielding relatively light squark and gluinos consistent with the darkmatter relic density data and the LEP bounds on the lightest Higgs scalar mass. This parameter space is only allowed for non-vanishing trilinear soft breaking term $A_0$. A significant region of the parameter space with large to moderate negative values of $A_0$ consistent with the stability of the scalar potential and relic density production via neutralino annihilation and/or neutralino - stau coannihilation yields observable signal via the jets + missing transverse energy channel. The one lepton + jets + missing energy signal is also viable over a smaller but non-trivial parameter space. The ratio of the size of the two signals - free from theoretical uncertainties - may distinguish between different relic density generating mechanisms. With efficient $\tau$-tagging facilities at 7 $TeV$ the discriminating power may increase significantly. We also comment on other dark matter relic density allowed mSUGRA scenarios and variants there of in the context of LHC-7 $TeV$.Comment: Brief comments on signals at 7 TeV in the Higgs funnel region of mSUGRA, models with non universal scalar and gaugino masses have been added. Accepted for publication in PR