129 research outputs found
On Direct Verification of Warped Hierarchy-and-Flavor Models
We consider direct experimental verification of warped models, based on the
Randall-Sundrum (RS) scenario, that explain gauge and flavor hierarchies,
assuming that the gauge fields and fermions of the Standard Model (SM)
propagate in the 5D bulk. Most studies have focused on the bosonic Kaluza Klein
(KK) signatures and indicate that discovering gauge KK modes is likely
possible, yet challenging, while graviton KK modes are unlikely to be
accessible at the LHC, even with a luminosity upgrade. We show that direct
evidence for bulk SM fermions, {\it i.e.} their KK modes, is likely also beyond
the reach of a luminosity-upgraded LHC. Thus, neither the spin-2 KK graviton,
the most distinct RS signal, nor the KK SM fermions, direct evidence for bulk
flavor, seem to be within the reach of the LHC. We then consider hadron
colliders with 21, 28, and 60 TeV. We find that discovering the
first KK modes of SM fermions and the graviton typically requires the Next
Hadron Collider (NHC) with TeV and
ab of integrated luminosity. If the LHC yields hints of these warped
models, establishing that Nature is described by them, or their 4D CFT duals,
requires an NHC-class machine in the post-LHC experimental program.Comment: Revtex4, 21 pages, 11 figure
Neutrinos in a left-right model with a horizontal symmetry
We analyze the lepton sector of a Left-Right Model based on the gauge group
SU(2)_L x SU(2)_R x U(1), concentrating mainly on neutrino properties. Using
the seesaw mechanism and a horizontal symmetry, we keep the right-handed
symmetry breaking scale relatively low, while simultaneously satisfying
phenomenological constraints on the light neutrino masses. We take the
right-handed scale to be of order 10's of TeV and perform a full numerical
analysis of the model's parameter space, subject to experimental constraints on
neutrino masses and mixings. The numerical procedure yields results for the
right-handed neutrino masses and mixings and the various CP-violating phases.
We also discuss phenomenological applications of the model to neutrinoless
double beta decay, lepton-flavor-violating decays (including decays such as
\tau \to 3\mu) and leptogenesis.Comment: 26 pages, 4 figure
Underwater Navigation using Pseudolite
Using pseudolite or pseudo satellite, a proven technology for ground and space applications for the augmentation of GPS, is proposed for underwater navigation. Global positioning systems (GPS) like positioning for underwater system, needs minimum of four pseudolite-ranging signals for pseudo-range and accumulated delta range measurements. Using four such measurements and using the models of underwater attenuation and delays, the navigation solution can be found. However, for application where the one-way ranging does not give good accuracy, alternative algorithms based upon the bi-directional and self-difference ranging is proposed using selfcalibrated pseudolite array algorithm. The hardware configuration is proposed for pseudolite transceiver for making the self-calibrated array. The pseudolite array, fixed or moored under the sea, can give position fixing similar to GPS for underwater applications.Defence Science Journal, 2011, 61(4), pp.331-336, DOI:http://dx.doi.org/10.14429/dsj.61.108
Modelling and Simulation of Pseudolite-based Navigation: A GPS-independent Radio Navigation System
The use of global positioning system (GPS) for precision guidance of weapons is being questioned due to its vulnerability of jamming and spoofing for non-military code users. In this paper a novel approach is proposed for guidance of weapons where use of GPS or other civilian Satellite-based navigation system is threatened. The proposed approach is modelled and simulated using SIMULINK for realistic trajectories and scenario. The results of simulation are validated with the actual GPS data
B-factory Signals for a Warped Extra Dimension
We study predictions for B-physics in a class of models, recently introduced,
with a non-supersymmetric warped extra dimension. In these models few () TeV Kaluza-Klein masses are consistent with electroweak data due to bulk
custodial symmetry. Furthermore, there is an analog of GIM mechanism which is
violated by the heavy top quark (just as in SM) leading to striking signals at
-factories:(i) New Physics (NP) contributions to transitions
are comparable to SM. This implies that, within this NP framework, the success
of SM unitarity triangle fit is a ``coincidence'' Thus, clean extractions of
unitarity angles via e.g. are likely to
be affected, in addition to O(1) deviation from SM prediction in mixing.
(ii) O(1) deviation from SM predictions for in rate as well
as in forward-backward and direct CP asymmetry. (iii) Large mixing-induced CP
asymmetry in radiative B decays, wherein the SM unamibgously predicts very
small asymmetries. Also with KK masses 3 TeV or less, and with anarchic Yukawa
masses, contributions to electric dipole moments of the neutron are roughly 20
times larger than the current experimental bound so that this framework has a
"CP problem".Comment: On further consideration, we found that our framework does have a "CP
problem" in that though contributions to neutron's electric dipole moment
from CKM-like phases vanish at the one-loop level, sizeable contributions are
induced by Majorana-like phases. Last sentence of abstract is changed along
with para #3 and 4 on page
Extended Friedberg Lee hidden symmetries, quark masses and CP-violation with four generations
Motivated in part by the several observed anomalies involving CP asymmetries
of B and B_s decays, we consider the Standard Model with a 4th sequential
family (SM4) which seems to offer a rather simple resolution. We initially
assume T-invariance by taking the up and down-quark 4x4 mass matrix to be real.
Following Friedberg and Lee (FL), we then impose a "hidden" symmetry on the
unobserved ("hidden") up and down-quark SU(2) states. The hidden symmetry for
four generations ensures the existence of two zero-mass eigenstates, which we
take to be the (u,c) and (d,s) states in the up and down-quark sectors,
respectively. Then, we simultaneously break T-invariance and the hidden
symmetry by introducing two phase factors in each sector. This breaking
mechanism generates the small quark masses m_u, m_c and m_d, m_s which, along
with the orientation of the hidden symmetry, determine the size of CP-violation
in the SM4. For illustration we choose a specific physical picture for the
hidden symmetry and the breaking mechanism that reproduces the observed quark
masses, mixing angles and CP-violation, and at the same time allows us to
further obtain very interesting relations/predictions for the mixing angles of
t and t'. For example, with this choice we get V_{td} ~ (V_{cb}/V_{cd} -
V_{ts}/V_{us}) + O(\lambda^2) and V_{t'b} ~ V_{t'd}x(V_{cb}/V_{cd}), V_{tb'} ~
V_{t'd}x(V_{ts}/V_{us}), implying that V_{t'd} > V_{t'b},V_{tb'}. We
furthermore find that the Cabibbo angle is related to the orientation of the
hidden symmetry and that the key CP-violating quantity of our model at
high-energies, J_{SM4} = Im[V_{tb} V_{t'b}^* V_{t'b'} V_{tb'}^*], which is the
high-energy analogue of the Jarlskog invariant of the SM, is proportional to
the light-quark masses and the measured CKM angles.Comment: 19 page
Two body decays of the -quark: Applications to direct CP violation, searches for electro-weak penguins and new physics
A systematic experimental search for two-body hadronic decays of the b-quark
of the type b to quark + meson is proposed. These reactions have a well defined
experimental signature and they should be theoretically cleaner compared to
exclusive decays. Many modes have appreciable branching ratios and partial rate
asymmetries may also be quite large (about 8-50%) in several of them. In a few
cases electroweak penguins appear to be dominant and may be measurable. CP
violating triple correlation asymmetries provide a clean test of the Standard
Model.Comment: 12 pages 1 figure 1 tabl
SM with four generations: Selected implications for rare B and K decays
We extend our recent work and study implications of the Standard Model with
four generations (SM4) for rare B and K decays. We again take seriously the
several 2-3 anomalies seen in B, decays and interpret them in
the context of this simple extension of the SM. SM4 is also of course of
considerable interest for its potential relevance to dynamical electroweak
symmetry breaking and to baryogenesis. Using experimental information from
processes such as , and mixings, indirect
CP-violation from etc along with oblique corrections, we
constrain the relevant parameter space of the SM4, and find of about
400-600 GeV with a mixing angle in the range of about
(0.05 to 1.4) and with an appreciable CP-odd associated phase,
are favored by the current data. Given the unique role of the CP asymmetry in
due to its gold-plated nature, correlation of that with
many other interesting observables, including the semileptonic asymmetry
() are studied in SM4. We also identify several processes, such as , etc, that are significantly
different in SM4 from the SM. Experimentally the very distinctive process
is also discussed; the branching ratio can be larger or
smaller than in SM, , by a factor of
.Comment: v2: 49 pages, 20 eps figures, Corrected some typos, added few
references and minor changes with regard to direct CP in K pi. Also some
added information to facilitate direct comparison with Buras et al,
arXiv:1002.2126
Extracting information on CKM phases, electro-weak penguins and new physics from B --> VV decays
We derive constraints for modes ($V= vector meson) that allow
aquantitative assessment of the contributions from electroweak penguins (EWP)
and/or new physics. Interplay of direct CP with oscillation studies then leads
to the extraction of the angles alpha and gamma, using B--> K* omega rho and
B--> rho omega (phi) respectively, if by using our constraint equations it can
be experimentally demonstrated that color-suppressed EWP are small.Comment: 12 pages, 0 figures; revised and expande
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
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