17,752 research outputs found
A test of local Lorentz invariance with Compton scattering asymmetry
We report on a measurement of the constancy and anisotropy of the speed of
light relative to the electrons in photon-electron scattering. We used the
Compton scattering asymmetry measured by the new Compton polarimeter in Hall~C
at Jefferson Lab to test for deviations from unity of the vacuum refractive
index (). For photon energies in the range of 9 - 46 MeV, we obtain a new
limit of . In addition, the absence of sidereal
variation over the six month period of the measurement constrains any
anisotropies in the speed of light. These constitute the first study of Lorentz
invariance using Compton asymmetry. Within the minimal standard model extension
framework, our result yield limits on the photon and electron coefficients
, and .
Although, these limits are several orders of magnitude larger than the current
best limits, they demonstrate the feasibility of using Compton asymmetry for
tests of Lorentz invariance. Future parity violating electron scattering
experiments at Jefferson Lab will use higher energy electrons enabling better
constraints.Comment: 7 pages, 5 figure
Formation of ultracold LiRb molecules by photoassociation near the Li (2s 2S1/2) + Rb (5p 2P1/2) asymptote
We report the production of ultracold 7Li85Rb molecules by photoassociation
(PA) below the Li (2s 2S1/2) + Rb (5p 2P1/2) asymptote. We perform PA
spectroscopy in a dual-species 7Li-85Rb magneto-optical trap (MOT) and detect
the PA resonances using trap loss spectroscopy. We observe several strong PA
resonances corresponding to the last few bound states, assign the lines and
derive the long range C6 dispersion coefficients for the Li (2s 2S1/2) + Rb (5p
2P1/2) asymptote. We also report an excited-state molecule formation rate
(P_LiRb) of ~10^7 s^-1 and a PA rate coefficient (K_PA) of ~4x10^-11 cm^3/s,
which are both among the highest observed for heteronuclear bi-alkali
molecules. These suggest that PA is a promising route for the creation of
ultracold ground state LiRb molecules.Comment: 6 page
Anomalous thermal expansion of SbTe topological insulator
We have investigated the temperature dependence of the linear thermal
expansion along the hexagonal c axis (), in-plane resistivity
(), and specific heat () of the topological insulator SbTe
single crystal. exhibits a clear anomaly in the temperature region
204-236 K. The coefficient of linear thermal expansion decreases
rapidly above 204 K, passes through a deep minimum at around 225 K and then
increases abruptly in the region 225-236 K. is negative in the
interval 221-228 K. The temperature dependence of both and can
be described well by the Debye model from 2 to 290 K, excluding the region
around the anomaly in
Anopheline fauna of parts of Tirap district, Arunachal Pradesh with reference to malaria transmission
In a survey on the anopheline fauna in highly malaria endemic areas of the Tirap district of Arunachal Pradesh, 7476 anophelines belonging to 17 species were collected, including seven species of anophelines which are recognized malaria vectors in India. Anopheles tessellatus and A. jamesii were recorded for the first time in this area. The parasitological survey revealed that the area was endemic for malaria particularly P. falciparum. the slide positivity rate and slide falciparum rate being 25.63 and 19.21 per cent respectively. On dissection of 10 anopheies species, malarial infection was detected in two viz., A. minimus and A. dirus
Signature of strong atom-cavity interaction on critical coupling
We study a critically coupled cavity doped with resonant atoms with
metamaterial slabs as mirrors. We show how resonant atom-cavity interaction can
lead to a splitting of the critical coupling dip. The results are explained in
terms of the frequency and lifetime splitting of the coupled system.Comment: 8 pages, 5 figure
Detection of SUSY Signals in Stau Neutralino Co-annihilation Region at the LHC
We study the prospects of detecting the signal in the stau neutralino
co-annihilation region at the LHC using tau leptons. The co-annihilation signal
is characterized by the stau and neutralino mass difference (dM) to be 5-15 GeV
to be consistent with the WMAP measurement of the cold dark matter relic
density as well as all other experimental bounds within the minimal
supergravity model. Focusing on tau's from neutralino_2 --> tau stau --> tau
tau neutralino_1 decays in gluino and squark production, we consider inclusive
MET+jet+3tau production, with two tau's above a high E_T threshold and a third
tau above a lower threshold. Two observables, the number of opposite-signed tau
pairs minus the number of like-signed tau pairs and the peak position of the
di-tau invariant mass distribution, allow for the simultaneous determination of
dM and M_gluino. For dM = 9 GeV and M_gluino = 850 GeV with 30 fb^-1 of data,
we can measure dM to 15% and M_gluino to 6%.Comment: 4 pages LaTex, 3 figures. To appear in Proceedings of SUSY06, the
14th International Conference on Supersymmetry and the Unification of
Fundamental Interactions, UC Irvine, California, 12-17 June 2006. A typo in a
reference is correcte
Influence of Polymer Matrix and Magnetic Field on the Optical and Electrical Properties of Fine Particles of Nickel Ferrite
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