191 research outputs found
Flavor Structure of Warped Extra Dimension Models
We recently showed, in hep-ph/0406101, that warped extra dimensional models
with bulk custodial symmetry and few TeV KK masses lead to striking signals at
-factories. In this paper, using a spurion analysis, we systematically study
the flavor structure of models that belong to the above class. In particular we
find that the profiles of the zero modes, which are similar in all these
models, essentially control the underlying flavor structure. This implies that
our results are robust and model independent in this class of models. We
discuss in detail the origin of the signals in B-physics. We also briefly study
other NP signatures that arise in rare K decays (), in rare
top decays [] and the possibilty of CP asymmetries
in decays to CP eigenstates such as and others. Finally we
demonstrate that with light KK masses, TeV, the above class of models
with anarchic Yukawas has a ``CP problem'' since contributions to the
neutron electric dipole moment are roughly 20 times larger than the current
experimental bound. Using AdS/CFT correspondence, these extra-dimensional
models are dual to a purely 4D strongly coupled conformal Higgs sector thus
enhancing their appeal.Comment: 41 pages, 52 pages including appendice
The isospin symmetry breaking effects in decays
The Fermi-Watson theorem is generalized to the case of two coupled channels
with different masses and applied to final state interaction in
decays. The impact of considered effect on the phase of the scattering
is estimated and shown that it can be crucial for scattering lengths extraction
from experimental data on decays
The neutron electric dipole form factor in the perturbative chiral quark model
We calculate the electric dipole form factor of the neutron in a perturbative
chiral quark model, parameterizing CP-violation of generic origin by means of
effective electric dipole moments of the constituent quarks and their
CP-violating couplings to the chiral fields. We discuss the relation of these
effective parameters to more fundamental ones such as the intrinsic electric
and chromoelectric dipole moments of quarks and the Weinberg parameter. From
the existing experimental upper limits on the neutron EDM we derive constraints
on these CP-violating parameters.Comment: 20 pages, 3 figure
Top quark electric and chromo electric dipole moments in the general two Higgs Doublet model
We study the electric and chromo electric dipole moment of top quark in the
general two Higgs Doublet model (model III). We analyse the dependency of this
quantity to the new phases coming from the complex Yukawa couplings and masses
of charged and neutral Higgs bosons. We observe that the electric and chromo
elecric dipole moments of top quark are at the order of 10^{-21} e cm and
10^{-20} g_s cm, which are extremely large values compared to ones calculated
in the SM and also two Higgs Doublet model with real Yukawa couplings.Comment: 9 pages,10 figure
Strong CP violation and the neutron electric dipole form factor
We calculate the neutron electric dipole form factor induced by the CP
violating theta-term of QCD, within a perturbative chiral quark model which
includes pion and kaon clouds. On this basis we derive the neutron electric
dipole moment and the electron-neutron Schiff moment. From the existing
experimental upper limits on the neutron electric dipole moment we extract
constraints on the theta-parameter and compare our results with other
approaches.Comment: 18 pages, 2 figures, accepted for publication in Phys. Atom. Nuc
Neutron Electric Dipole Moment In The Standard Model: Valence Quark Contributions
We present a complete three-loop calculation of the electric dipole moment of
the and quarks in the Standard Model. For the quark, more relevant
for the experimentally important neutron electric dipole moment, we find
cancellations which lead to an order of magnitude suppression compared with
previous estimates.Comment: 8 pages, revte
The Measure of Strong CP Violation
We investigate a controversial issue on the measure of CP violation in strong
in teractions. In the presence of nontrivial topological gauge configurations,
the -term in QCD has a profound effect: it breaks the CP symmetry. The
CP-violating amplitude is shown to be determined by the vacuum tunneling
process, where the semiclassical method makes most sense. We discuss a
long-standing dispute on whether the instanton dynamics satisfies or not the
anomalous Ward identity (AWI). The strong CP violation measure, when complying
with the vacuum alignment, is proportional to the topological susceptibility.
We obtain an effective CP-violating lagrangian different from that provided by
Baluni. To solve the IR divergence problem of the instanton computation, We
present a ``classically gauged'' Georgi-Manohar model and derive an effective
potential which uniquely determines an explicit symmetry breaking
sector. The CP violation effects are analyzed in this model. It is shown that
the strong CP problem and the problem are closely related. Some possible
solutions to both problems are also discussed with new insights.Comment: 37 pages in LateX, SFU-Preprint-92-
Probing exotic phenomena at the interface of nuclear and particle physics with the electric dipole moments of diamagnetic atoms: A unique window to hadronic and semi-leptonic CP violation
The current status of electric dipole moments of diamagnetic atoms which
involves the synergy between atomic experiments and three different theoretical
areas -- particle, nuclear and atomic is reviewed. Various models of particle
physics that predict CP violation, which is necessary for the existence of such
electric dipole moments, are presented. These include the standard model of
particle physics and various extensions of it. Effective hadron level combined
charge conjugation (C) and parity (P) symmetry violating interactions are
derived taking into consideration different ways in which a nucleon interacts
with other nucleons as well as with electrons. Nuclear structure calculations
of the CP-odd nuclear Schiff moment are discussed using the shell model and
other theoretical approaches. Results of the calculations of atomic electric
dipole moments due to the interaction of the nuclear Schiff moment with the
electrons and the P and time-reversal (T) symmetry violating
tensor-pseudotensor electron-nucleus are elucidated using different
relativistic many-body theories. The principles of the measurement of the
electric dipole moments of diamagnetic atoms are outlined. Upper limits for the
nuclear Schiff moment and tensor-pseudotensor coupling constant are obtained
combining the results of atomic experiments and relativistic many-body
theories. The coefficients for the different sources of CP violation have been
estimated at the elementary particle level for all the diamagnetic atoms of
current experimental interest and their implications for physics beyond the
standard model is discussed. Possible improvements of the current results of
the measurements as well as quantum chromodynamics, nuclear and atomic
calculations are suggested.Comment: 46 pages, 19 tables and 16 figures. A review article accepted for
EPJ
Detection of regulator genes and eQTLs in gene networks
Genetic differences between individuals associated to quantitative phenotypic
traits, including disease states, are usually found in non-coding genomic
regions. These genetic variants are often also associated to differences in
expression levels of nearby genes (they are "expression quantitative trait
loci" or eQTLs for short) and presumably play a gene regulatory role, affecting
the status of molecular networks of interacting genes, proteins and
metabolites. Computational systems biology approaches to reconstruct causal
gene networks from large-scale omics data have therefore become essential to
understand the structure of networks controlled by eQTLs together with other
regulatory genes, and to generate detailed hypotheses about the molecular
mechanisms that lead from genotype to phenotype. Here we review the main
analytical methods and softwares to identify eQTLs and their associated genes,
to reconstruct co-expression networks and modules, to reconstruct causal
Bayesian gene and module networks, and to validate predicted networks in
silico.Comment: minor revision with typos corrected; review article; 24 pages, 2
figure
The T2K Side Muon Range Detector
The T2K experiment is a long baseline neutrino oscillation experiment aiming
to observe the appearance of {\nu} e in a {\nu}{\mu} beam. The {\nu}{\mu} beam
is produced at the Japan Proton Accelerator Research Complex (J-PARC), observed
with the 295 km distant Super- Kamiokande Detector and monitored by a suite of
near detectors at 280m from the proton target. The near detectors include a
magnetized off-axis detector (ND280) which measures the un-oscillated neutrino
flux and neutrino cross sections. The present paper describes the outermost
component of ND280 which is a side muon range detector (SMRD) composed of
scintillation counters with embedded wavelength shifting fibers and Multi-Pixel
Photon Counter read-out. The components, performance and response of the SMRD
are presented.Comment: 13 pages, 19 figures v2: fixed several typos; fixed reference
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