10,155 research outputs found
Double-lepton polarization asymmetries in the (B -> K l^+ l^-) decay beyond the Standard Model
General expressions for the double-lepton polarizations in the (B -> K l^+
l^-) decay are obtained, using model independent effective Hamiltonian,
including all possible interactions. Correlations between the averaged
double-lepton polarization asymmetries and the branching ratio, as well as, the
averaged single-lepton polarization asymmetry are studied. It is observed that,
study of the double-lepton polarization asymmetries can serve as a good test
for establishing new physics beyond the Standard Model.Comment: 21 pages, 18 figures, LaTeX formatte
High Power, Continuous-wave Supercontinuum Generation in Highly Nonlinear Fibers Pumped with High Order, Cascaded Raman Fiber Amplifiers
A novel method for efficient generation of high power, equalized
continuous-wave supercontinuum source in an all conventional silica fiber
architecture is demonstrated. Highly nonlinear fiber (HNLF) is pumped in its
anomalous dispersion region using a novel, high power, L-band laser. The L-band
laser encompasses a 6th order cascaded Raman amplifier which is pumped with a
high power Ytterbium doped fiber laser and amplifies a low-power, tunable
L-band seed source. The supercontinuum generated 35W of power with ~40%
efficiency. The Supercontinuum spectrum was measured to have a high degree of
flatness of better than 5 dB over 400 nm of bandwidth (1.3 - 1.7 micron,
limited by spectrum analyzer range) and a power spectral density in this region
of >50 mW/nm. The extent of the SC spectrum is estimated to be upto 2 micronComment: 6 pages, 5 figure
Looking for the Top-squark at the Tevatron with four jets
The scalar partner of the top quark is relatively light in many models of
supersymmetry breaking. We study the production of top squarks (stops) at the
Tevatron collider and their subsequent decay through baryon-number violating
couplings such that the final state contains no leptons. Performing a
detector-level analysis, we demonstrate that, even in the absence of leptons or
missing energy, stop masses upto 210 \gev/c^2 can be accessible at the
Tevatron.Comment: 4 pages, 4 embedded figures, RevTe
Fe-spin reorientation in PrFeAsO : Evidences from resistivity and specific heat studies
We report the magnetic field dependence of resistivity () and specific
heat () for the non-superconducting PrFeAsO compound. Our study shows a
hitherto unobserved anomaly at in the resistivity and specific heat
data which arises as a result of the interplay of antiferromagnetic (AFM) Pr
and Fe sublattices. Below the AFM transition temperature (), Pr
moment orders along the crystallographic c axis and its effect on the iron
subsystem causes a reorientation of the ordered inplane Fe moments in a
direction out of the plane. Application of magnetic field introduces
disorder in the AFM Pr sublattice, which, in turn, reduces the out-of-plane
Pr-Fe exchange interaction responsible for Fe spin reorientation. Both in
() and curves, the peak at broadens with the
increase of due to the introduction of the disorder in the AFM Pr
sublattice by magnetic field. In () curve, the peak shifts towards
lower temperature with and disappears above 6 T while in curve
the peak remains visible up to 14 T. The broadening of the anomaly at
in with increasing further confirms that magnetic
field induces disorder in the AFM Pr sublattice.Comment: 8 pages, 10 Figure
New limits on top squark NLSP from ATLAS 4.7 data
Using the ATLAS 4.7 data on new physics search in the jets + \met
channel, we obtain new limits on the lighter top squark ()
considering all its decay modes assuming that it is the next to lightest
supersymmetric particle (NLSP). If the decay \lstop \ra c \lspone dominates
and the production of dark matter relic density is due to NLSP - LSP
co-annihilation then the lower limit on \mlstop is 240 GeV. The limit
changes to 200 GeV if the decay \lstop \ra b W \lspone dominates. Combining
these results it follows that \lstop NLSP induced baryogenesis is now
constrained more tightly.Comment: 9 pages, 2 figures, published in MPL
Chemical Phase Analysis
In many scientific investigations and technical operations it is necessary to know not only the total amount of an element of interest but also the amount of its different valencies , combinations or mineralogical forms. The diff-erent phases or forms of an element can usually be obser-ved of course by microscopical examination, X-ray diff-raction or other physical means . The frequent difficulty of obtaining by these techniques a rapid quantitative measure of the phases present. has led to the dcvelopiucut of many chemical procedures, based principally on a sele-ctive solvent , a chelate, resin or other isolating agent. The chemical approach , though it may suffer from certain deficiencies in accuracy and precision , has the merit
of quickly providing a reasonable satisfactory result. It does not require expensive and complicated instruments or workers with long experience in the interpretation of data . The popularity of chemical phase analysis in indu-strial practice, therefore , is not difficult to understan
Unparticle physics in diphoton production at the CERN LHC
We have considered the di-photon production with unparticle at LHC. The
contributions of spin-0 and spin-2 unparticle to the di-photon production are
studied in the invariant mass and other kinematical distributions, along with
their dependencies on the model dependent parameters. The signal corresponding
to the unparticle is significant for moderate coupling constant values.Comment: 17 pages, 15 eps figure
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