202 research outputs found
Using Jet Substructure at the LHC to Search for the Light Higgs Bosons of the CP-Violating MSSM
The CP-violating version of the Minimal Supersymmetric Standard Model (MSSM)
is an example of a model where experimental data do not preclude the presence
of light Higgs bosons in the range around 10 -- 110 GeV. Such light Higgs
bosons, decaying almost wholly to b-bbar pairs, may be copiously produced at
the LHC, but would remain inaccessible to conventional Higgs searches because
of intractable QCD backgrounds. We demonstrate that a significant number of
these light Higgs bosons would be boosted strongly enough for the pair of
daughter -jet pairs to appear as a single `fat' jet with substructure.
Tagging such jets could extend the discovery potential at the LHC into the
hitherto-inaccessible region for light Higgs bosons.Comment: LaTeX, 33 pages, 5 eps figures and 5 tables embedded. minor changes,
to appear in Physical Review
EPR study of the Jahn-Teller effect of Cu2+ in ZnTiF6·6H20
The 34-GHz EPR spectrum of Cu2+ in ZnTiF6·6H20 shows a Jahn-Teller effect with a transition
from a single-line spectrum at high temperatures to a multiline anisotropic spectrum. The transition
temperature on cooling varied with Cu concentration from 172 K for a sample containing 0.2
at.% Cu to roughly 90 K for a 46-at. % Cu sample. For dilute samples, the single-line spectrum
was isotropic at 300 K with g =2.223±0.005, but showed axial symmetry about the trigonal axis at
180 K with gj1 =2.226±0.005 and g~ =2.223±0.005. At 4.2 K, a "static" Jahn-Teller effect was
observed with six axially symmetric Cu2+ spectra, each with g 11 =2.470±0.005, g1 =2.100±0.005,
I A 11 I ~ I 06 X 10- 4 em -I, and I A 1 I ~30 X 10- 4 em - I. The z axis of these spectra was found to lie
along the fourfold axes of two cubes with a common [Ill] axis, rotated by 40"±2" with respect to
each other about this axis. Analysis of the 4.2-K data leads to the values q~O. 50 for the Ham
reduction factor and K~O. 26 for the Fenni contact parameter, with A uA 1 < 0. An activation energy
of about 100 cm-1 was deduced from the gradual increase of the anisotropy of the spectrum on
cooling in the low-temperature region
A mathematical model for improving the mechanism of satellite antenna
The functionality of any type of antenna could be
traced to the Maxwell's electromagnetic field equations. However,salient operational problems of antennas are traced back to the Maxwell's. The inclusion of the effects of particulate to either transmission or reception unit of antenna is paramount. The Schrodinger was used to model a now reformed Maxwell's equation which explains in details the electrostatic and induced magnetic field of either transmitting or receiving antenna. This theory applies to only to stationary satellite antennas
Jahn-Teller EPA spectra of Cu2 + in MgSif6.6H20
The 34 GHz EPR spectrum ofCu2+ in MgSiF6-6H20 showed a "static" Jahn-Teller effect at 4.2
K with two inequivalent Jahn- Teller sites per unit cell. The six axially symmetric sets of Cu2+
lines had their z axes parallel to the three tetragonal axes of two cubes, which were rotated by
approximately 40" with respect to each other about a common (Ill) axis, which is the crystal c
axis. The measured spin-Hamiltonian parameters at 4.2 K for each set of lines were
g11 = 2.47 ± 0.01, g1 = 2.10 ± 0.01 , and lA 11 1 = (110 ± 3)X 10- 4 em- •. There was a gradual
decrease in the anisotropy of the spectrum on warming the crystal, with a single, nearly isotropic
line being observed above 220 K. At 270 K the spectrum had axial symmetry about the c axis with
Kn = 2.23 ± 0.01 and g~ = 2.25 ± 0.01 . The temperature evolution of the spectrum was
interpreted in terms of a Boltzmann distribution over inequivalent distorted Jahn-Teller
configurations, with one potential well lowered by an amount L1:::::: I 05 em- 1 below the other two
Assessment of wetland change dynamics of Chennai coast, Tamil Nadu, India, using satellite remote sensing
1258-1266The coastal wetlands of Chennai are increasingly being affected by anthropogenic factors, such as urbanization, residential, and industrial development. This study helps to monitor and map the dynamics of the coastal wetlands of Chennai using Landsat satellite images of 1988, 1996, 2006, and 2016 by following a supervised classification method. Post-classification wetland change detection was done in three temporal phases, that is, 1988 1996, 1996 2006, and 2006 2016. Change detection matrix analysis was performed to identify the from to changes. Ground truthing was carried out to validate the wetland classes. The overall accuracy of the classified image was 79.29% and the kappa coefficient was 0.7600. These results were imported into a GIS environment for further analysis. It was found that the wetlands have decreased to an alarming extent in the past 28 years from 23.14% in 1988 to 15.79% in 2016 of the
total study area, owing to conversion of wetlands into industrial development, urban expansion, and other
developmental activities
Observation of the cubic-field splitting of an excited S = 2 manifold in a cubic copper tetramer
EPR measurements on single crystals of Cu40Cl6(triphenylphosphine oxide)4 at liquid helium
temperatures in the frequency ranges 14-17 and 34-35 GHz were fitted to a simple cubicS= 2
spin Hamiltonian with g = 2.10 ± 0.01 and a zero-field splitting of(0.53 ± 0.01) em - 1
• From the
decrease in intensity of the S = 2 spectrum on cooling below 4.2 K and the absence of an S = 1
spectrum, the S = 2 manifold was deduced to lie ( 14 ± 1) em- 1 above a nonmagnetic ground
state. The EPR results are used as a test of the various theories developed to explain the magnetic
susceptibility of copper tetramer
The phase transition temperature at 145 K in cadmium calcium acetat hexahydrate as a function of Cu2+ probe concentration
The temperature of the structural phase transition in cadmium calcium acetate hexahydrate as
a function of Cu2+ concentration has been studied with electron paramagnetic resonance
(EPR). The phase transition temperature was found to vary from 144 to 124 K as the amount
of copper varied from 0.07% to 1.3% of the sample weight. An extrapolation of this data
predicts a structural phase transition at 145 Kin pure cadmium calcium acetate hexahydrate.
Good fits of the data to second-order phase transition theory was obtained with critical
exponents close to 0.30
Neutrino masses along with fermion mass hierarchy
Recently a new mechanism has been proposed to cure the problem of fermion
mass hierarchy in the Standard Model (SM) model. In this scenario, all SM
charged fermions other than top quark arise from higher dimensional operators
involving the SM Higgs field. This model also predicted some interesting
phenomenology of the Higgs boson. We generalize this model to accommodate
neutrino masses (Dirac & Majorana) and also obtain the mixing pattern in the
leptonic sector. To generate neutrino masses, we add extra three right handed
neutrinos in this model.Comment: 20 pages, the content on results and phenomenology have been
expanded, a new section on UV completion of the model has been added and also
some new references, this version has been accepted by Physical Review
Fishery resources of spiny lobsters in the Andaman Island, India
The Andaman and Nicobar (A&N) Islands is the largest archipelago in the Bay of Bengal. In spite
of availability of diverse lobster resources, there is no organised lobster fishing in the Islands. The
main objective of the study was to collect baseline data on the lobster resources of the Andaman Island.
Periodic field surveys were carried out at 33 landing centres in the Andaman and data were collected
by direct observation and questionnaires. Mechanised and non-mechanised fishing crafts are engaged
in lobster fishing in the Island. Lobsters are manually caught by spears, gillnet, shoreseine and handpicking.
Six commercially important species of spiny lobsters, Panulirus penicillatus, P. versicolor,
P. homarus, P. ornatus, P. polyphagus and P. longipes are present in the island. Among them, P.
penicillatus dominated the landings throughout the study period (1999-2000), with maximum catch
in January, followed by P. versicolor. The total lobster landings in Andaman during the study period
were estimated as 3.16 tonnes with maximum landings in south Andaman (Port Blair)
Higgs pair production in association with a vector boson at e+e- colliders in theories of higher dimensional gravity
The models of large extra compact dimensions, as suggested by Arkani-Hamed,
Dimopoulos and Dvali, predict exciting phenomenological consequences with
gravitational interactions becoming strong at the TeV scale. Such theories can
be tested at the existing and future colliders. In this paper, we study the
contribution of virtual Kaluza-Klein excitations (both spin-0 and 2) in the
process and at future linear collider
(NLC). We find that the virtual exchange KK gravitons can modify the
cross-section significantly from its Standard Model
value and will allow the effective string scale to be probed up to 6.6 TeV. The
second process is absent at the tree level in the standard model, and can
therefore be used to put limits on the effective string scale of 7.4 TeV.Comment: One new reference is added, some minor corrections, version to appear
in Physical Review
- …