924 research outputs found
Muon anomalous magnetic moment confronts exotic fermions and gauge bosons
We investigate the status of models containing exotic fermions or extra
Z-like neutral gauge bosons in the light of the recent data on anomalous
magnetic moment of muon. We find that it is possible to extract interesting
bounds on the parameters characterizing such models. The bounds are
particularly strong if the new flavour-changing neutral currents are axial
vectorlike.Comment: Additional figures included, minor modifications made in the tex
Muon Anomalous and Gauged Models
In this paper we study contribution to of the muon anomalous
magnetic dipole moment in gauged models. Here are
the lepton numbers. We find that there are three classes of models which can
produce a large value of to account for possible discrepancy between the
experimental data and the Standard Model prediction. The three classes are: a)
Models with an exact . In these models, is
massless. The new gauge interaction coupling is constrained
to be . b) Models with broken
and the breaking scale is not related to electroweak
symmetry breaking scale. The gauge boson is massive. The allowed range of
the coupling and the mass are constrained, but mass can be large; And
c) The is broken and the breaking scale is related to the
electroweak scale. In this case the mass is constrained to be
GeV. We find that there are interesting experimental signatures in
in these models.Comment: 13 pages, 9 figure
Systematic search for successful lepton mixing patterns with nonzero theta_13
We perform a systematic search for simple but viable lepton mixing patterns.
Our main criterion is that the mixing matrix can be parameterized by three
rotation angles, which are simple fractions of pi. These simple rotation angles
possess exact expressions for their sines and cosines, and often arise in the
flavor symmetry models. All possible parameterizations of the mixing matrix are
taken into account. In total, twenty successful mixing patterns are found to be
consistent with the latest neutrino oscillation data (including the recent T2K
results) in the CP conserving case, whereas fifteen mixing patterns are allowed
in the maximal CP violating case. Potential radiative corrections to the
constant mixing patterns are also calculated by solving the renormalization
group equations.Comment: 10 pages, 4 figures, 2 tables; version to be published in Nuclear
Physics
Z_2 Symmetry Prediction for the Leptonic Dirac CP Phase
Model-independent consequences of applying a generalized hidden horizontal
Z_2 symmetry to the neutrino mass matrix are explored. The Dirac CP phase
delta_D can be expressed in terms of the three mixing angles as 4 c_a s_a c_s
s_s s_x cos delta_D = (s^2_s - c^2_s s^2_x) (c^2_a - s^2_a) where the s_i, c_i
are sines and cosines of the atmospheric, solar, and reactor angles. This
relation is independent of neutrino masses and whether neutrinos are Dirac- or
Majorana-type. Given the present constraints on the angles, delta_D is
constrained to be almost maximal, a result which can be explored in experiments
such as NOvA and T2K. The Majorana CP phases do not receive any constraint and
are thus model-dependent. Also a distribution of theta_x with a lower limit is
obtained without specifying delta_D.Comment: 5 pages, 4 figures; Condensed version or PLB with references added;
for more details see the previous versio
Muon Anomalous Magnetic Moment and Lepton Flavor Violation
A non-universal interaction, which involves only the third family leptons
induces lepton flavor violating couplings and contributes to the anomalous
magnetic moment of muon. In this paper, we study the effects of non-universal
interaction on muon (g-2) and rare decay by using an
effective lagrangian technique, and a phenomenological model where
couples only to the third family lepton. We find that the deviation
from the theory can be explained and the induced rate
could be very close to the current experimental limit. In the model,
has to be lighter than 2.6 TeV.Comment: references added, the version to appear in PR
Cache "less for more" in information-centric networks (extended version)
Ubiquitous in-network caching is one of the key aspects of information-centric networking (ICN) which has received widespread research interest in recent years. In one of the key relevant proposals known as Content-Centric Networking (CCN), the premise is that leveraging in-network caching to store content in every node along the delivery path can enhance content delivery. We question such an indiscriminate universal caching strategy and investigate whether caching less can actually achieve more. More specifically, we study the problem of en route caching and investigate if caching in only a subset of nodes along the delivery path can achieve better performance in terms of cache and server hit rates. We first study the behavior of CCN's ubiquitous caching and observe that even naĂŻve random caching at a single intermediate node along the delivery path can achieve similar and, under certain conditions, even better caching gain. Motivated by this, we propose a centrality-based caching algorithm by exploiting the concept of (ego network) betweenness centrality to improve the caching gain and eliminate the uncertainty in the performance of the simplistic random caching strategy. Our results suggest that our solution can consistently achieve better gain across both synthetic and real network topologies that have different structural properties. We further find that the effectiveness of our solution is correlated to the precise structure of the network topology whereby the scheme is effective in topologies that exhibit power law betweenness distribution (as in Internet AS and WWW networks)
Parametrizing the Lepton Mixing Matrix in terms of Charged Lepton Corrections
We consider a parametrization of the lepton mixing matrix in which the
deviations from maximal atmospheric mixing and vanishing reactor mixing are
obtained in terms of small corrections from the charged lepton sector.
Relatively large deviations for the reactor mixing angle from zero as indicated
by T2K experiment can be obtained in this parametrization. We are able to
further reduce the number of complex phases, thus, simplifying the analysis. In
addition, we have obtained the sides of unitarity triangles and the vacuum
oscillation probabilities in this parametrization. The Jarlskog rephasing
invariant measure of CP violation at the leading order has a single phase
difference which can be identified as Dirac-type CP violating phase in this
parametrization.Comment: New references added, Phys. Lett. B (to appear
Discrete Flavour Symmetries in Light of T2K
We show that a non-vanishing angle theta_13 of order 0.1 can be predicted in
the framework of discrete flavour symmetries. We assume that left-handed
leptons transform as triplets under a group G_f which is broken in such a way
that neutrino and charged lepton sectors remain invariant under the subgroups
G_nu and G_e of G_f, respectively. In this limit mixing angles and the Dirac CP
violating phase delta_CP are determined. By choosing G_f=Delta(6 n^2) (n=4,8),
G_nu=Z_2 x Z_2 and G_e=Z_3 we find sin^2 theta_13=0.045(0.011) for n=4(8). At
the same time theta_23 and theta_12 remain close to their experimental best fit
values, particularly in the case n=8, where sin^2 theta_23 = 0.424 and sin^2
theta_12 = 0.337. delta_CP is predicted to be 0 or pi so that CP is conserved
in our examples.Comment: 1+11 pages, 1 figure; v2: matches journal versio
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