3,002 research outputs found
Effects of Top-quark Compositeness on Higgs Boson Production at the LHC
Motivated by the possibility that the right-handed top-quark (t_R) is
composite, we discuss the effects of dimension-six operators on the Higgs boson
production at the LHC. When t_R is the only composite particle among the
Standard Model (SM) particles, the (V+A)\otimes (V+A) type four-top-quark
contact interaction is expected to have the largest coefficient among the
dimension-six operators, according to the Naive Dimensional Analysis (NDA). We
find that, to lowest order in QCD and other SM interactions, the cross section
of the SM Higgs boson production via gluon fusion does not receive corrections
from one insertion of the new contact interaction vertex. We also discuss the
effects of other dimension-six operators whose coefficients are expected to be
the second and the third largest from NDA. We find that the operator which
consists of two t_R's and two SM Higgs boson doublets can recognizably change
the Higgs boson production cross section from the SM prediction if the cut-off
scale is \sim 1TeV.Comment: 12 pages, 7 figures. v2: explanations improved in Section 3, other
minor changes. Version published in JHE
Abnormal modulation of atmospheric parameters during the tsunami of 2004
This paper discusses the abnormal changes in weather elements observed at a tropical mountain location and a coastal station in India. Abnormal changes were noticed in the atmospheric parameters at a time close to the occurrence of tsunami on the Indian coasts due to high magnitude earthquakes in the Sumatra region on 26 December 2004. Close to the time of this earthquake occurrence, uncharacteristic and large magnitude changes in weather elements were recorded at Braemore (8o45â²N, 77o05â²E, 360 m amsl), a mountain field station at Western Ghats. Abnormal changes were also recorded at Minambakkam (13oN, 80o18â²E, 16 m SLP), close to eastern coastal belts. In the Braemore field station, simultaneous changes were observed in the atmospheric parameters; decrease in pressure by 0.6 hPa, increase in relative humidity by 30 and a prominent reduction in air temperature by more than 3oC on the day of tsunami. Also, unusually the relative humidity did not reach 100 on the previous night. However, in the Minambakkam station, the relative humidity increased by 10 associated with a sharp decrease in temperature by about 2.5oC. The changes in both the stations occurred almost at the same time and duration. Therefore, it may be concluded that these changes are associated with the high magnitude earthquake and subsequent tsunami
Theoretical studies on space debris recycling and energy conversion system in the International Space Station
The space debris management and alleviation in the microgravity environment
is a dynamic research theme of contemporary interest. Herein, we provide a
theoretical proof of the concept of a lucrative energy conversion system that is
capable of changing the space debris into useful powders in the International
Space Station (ISS) for various bids. A specially designed broom is adapted to
collect the space debris of various sizes. An optical sorting method is proposed
for the debris segregation in the ISS by creating an artificial gravitational field.
It could be done by using the frame-dragging effect or gravitomagnetism. An
induction furnace is facilitated for converting the segregated metal-scrap into
liquid metal. A fuel-cell aided water atomization method is proposed for transforming the liquid debris into metal powder. The high-energetic metal powders
obtained from the space debris could be employed for producing propellants for
useful aerospace applications, and the silicon powder obtained could be used
for making soil for fostering the pharmaceutical-flora in the space lab in the
future aiming for the scarce-drug discoveries for high-endurance health care
management. The proposed energy conversion system is a possible alternative
for the space debris extenuation and its real applications in orbiting laboratories
through the international collaboration for the benefits to humanity
Traditional knowledge for dairy animals in Una district of Himachal Pradesh
662-668Traditional knowledge (TK), also known as indigenous knowledge (IK) or local knowledge (LK) generally refers to the matured long-standing traditions and practices of certain regional, indigenous, or local communities. India stands at number 1 in milk production as dairy master across the world. However, due to large number of animal population, distant/remote location, shortage of veterinary staff, some time, veterinary aids are not available to the farmers. In such instances, it is the traditional knowledge of the people which guides them to mitigate the sufferings of the animals. In this article, some of the ITKs are described based on oral communication with the people
Matter and singularities
We analyze the structure of matter representations arising from codimension
two singularities in F-theory, focusing on gauge groups SU(N). We give a
detailed local description of the geometry associated with several types of
singularities and the associated matter representations. We also construct
global F-theory models for 6D and 4D theories containing these matter
representations. The codimension two singularities encountered include examples
where the apparent Kodaira singularity type does not need to be completely
resolved to produce a smooth Calabi-Yau, examples with rank enhancement by more
than one, and examples where the 7-brane configuration is singular. We identify
novel phase transitions, in some of which the gauge group remains fixed but the
singularity type and associated matter content change along a continuous family
of theories. Global analysis of 6D theories on P^2 with 7-branes wrapped on
curves of small degree reproduces the range of 6D supergravity theories
identified through anomaly cancellation and other consistency conditions.
Analogous 4D models are constructed through global F-theory compactifications
on P^3, and have a similar pattern of SU(N) matter content. This leads to a
constraint on the matter content of a limited class of 4D supergravity theories
containing SU(N) as a local factor of the gauge group.Comment: 55 pages, 7 figures; v2: references added; v3: minor correctio
Real-space mapping of tailored sheet and edge plasmons in graphene nanoresonators
Plasmons in graphene nanoresonators have many potential applications in photonics and optoelectronics, including room-temperature infrared and terahertz photodetectors, sensors, reflect arrays or modulators1, 2, 3, 4, 5, 6, 7. The development of efficient devices will critically depend on precise knowledge and control of the plasmonic modes. Here, we use near-field microscopy8, 9, 10, 11 between λ0 = 10–12 μm to excite and image plasmons in tailored disk and rectangular graphene nanoresonators, and observe a rich variety of coexisting Fabry–Perot modes. Disentangling them by a theoretical analysis allows the identification of sheet and edge plasmons, the latter exhibiting mode volumes as small as 10−8λ03. By measuring the dispersion of the edge plasmons we corroborate their superior confinement compared with sheet plasmons, which among others could be applied for efficient 1D coupling of quantum emitters12. Our understanding of graphene plasmon images is a key to unprecedented in-depth analysis and verification of plasmonic functionalities in future flatland technologies.Peer ReviewedPostprint (author's final draft
Bio-nanotechnology application in wastewater treatment
The nanoparticles have received high interest in the field of medicine and water purification, however, the nanomaterials produced by chemical and physical methods are considered hazardous, expensive, and leave behind harmful substances to the environment. This chapter aimed to focus on green-synthesized nanoparticles and their medical applications. Moreover, the chapter highlighted the applicability of the metallic nanoparticles (MNPs) in the inactivation of microbial cells due to their high surface and small particle size. Modifying nanomaterials produced by green-methods is safe, inexpensive, and easy. Therefore, the control and modification of nanoparticles and their properties were also discussed
Weak coupling large-N transitions at finite baryon density
We study thermodynamics of free SU(N) gauge theory with a large number of
colours and flavours on a three-sphere, in the presence of a baryon number
chemical potential. Reducing the system to a holomorphic large-N matrix
integral, paying specific attention to theories with scalar flavours (squarks),
we identify novel third-order deconfining phase transitions as a function of
the chemical potential. These transitions in the complex large-N saddle point
configurations are interpreted as "melting" of baryons into (s)quarks. They are
triggered by the exponentially large (~ exp(N)) degeneracy of light baryon-like
states, which include ordinary baryons, adjoint-baryons and baryons made from
different spherical harmonics of flavour fields on the three-sphere. The phase
diagram of theories with scalar flavours terminates at a phase boundary where
baryon number diverges, representing the onset of Bose condensation of squarks.Comment: 38 pages, 7 figure
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