397 research outputs found
Modified Higgs couplings and unitarity violation
Prompted by the recent observation of a Higgs-like particle at the CERN Large
Hadron Collider (LHC), we investigate a quantitative correlation between
possible departures of the gauge and Yukawa couplings of this particle from
their Standard Model expectations and the scale of unitarity violation in the
processes and .Comment: 6 pages, 6 eps figures, Arrayeq.sty attached; v2: minor updates,
version published: PRD 87 (2013) 011702(R), Rapid Communicatio
symmetry and the quark mixing matrix
We impose an symmetry on the quark fields under which two of three
quarks transform like a doublet and the remaining one as singlet, and use a
scalar sector with the same structure of doublets. After gauge symmetry
breaking, a subgroup of the remains unbroken. We show that
this unbroken subgroup can explain the approximate block structure of the CKM
matrix. By allowing soft breaking of the symmetry in the scalar sector,
we show that one can generate the small elements, of quadratic or higher order
in the Wolfenstein parametrization of the CKM matrix. We also predict the
existence of exotic new scalars, with unconventional decay properties, which
can be used to test our model experimentally.Comment: 7 pages, no figur
Scalar sector properties of two-Higgs-doublet models with a global U(1) symmetry
We analyze the scalar sector properties of a general class of
two-Higgs-doublet models which has a global U(1) symmetry in the quartic terms.
We find constraints on the parameters of the potential from the considerations
of unitarity of scattering amplitudes, the global stability of the potential
and the -parameter. We concentrate on the spectrum of the non-standard
scalar masses in the decoupling limit which is preferred by the Higgs data at
the LHC. We exhibit charged-Higgs induced contributions to the diphoton decay
width of the 125\,GeV Higgs boson and its correlation with the corresponding
width.Comment: 12 pages, 15 eps figure files; minor modifications made and a few
references adde
Kodaikanal Digitized White-light Data Archive (1921-2011): Analysis of various solar cycle features
Long-term sunspot observations are key to understand and predict the solar
activities and its effects on the space weather.Consistent observations which
are crucial for long-term variations studies,are generally not available due to
upgradation/modifications of observatories over the course of time. We present
the data for a period of 90 years acquired from persistent observation at the
Kodaikanal observatory in India. We use an advanced semi-automated algorithm to
detect the sunspots form each calibrated white-light image. Area, longitude and
latitude of each of the detected sunspots are derived. Implementation of a
semi-automated method is very necessary in such studies as it minimizes the
human bias in the detection procedure. Daily, monthly and yearly sunspot area
variations obtained from the Kodaikanal, compared well with the Greenwich
sunspot area data. We find an exponentially decaying distribution for the
individual sunspot area for each of the solar cycles. Analyzing the histograms
of the latitudinal distribution of the detected sunspots, we find Gaussian
distributions, in both the hemispheres, with the centers at 15
latitude. The height of the Gaussian distributions are different for the two
hemispheres for a particular cycle. Using our data, we show clear presence of
Waldmeier effect which correlates the rise time with the cycle amplitude. Using
the wavelet analysis, we explored different periodicities of different time
scales present in the sunspot area times series.Comment: Accepted for Publication in A&
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