777 research outputs found
Monotonically improving limit-optimal strategies in finite state decision processes
In every finite-state leavable gambling problem and in every finite-state Markov decision process with discounted, negative or positive reward criteria there exists a Markov strategy which is monotonically improving and optimal in the limit along every history. An example is given to show that for the positive and gambling cases such strategies cannot be constructed by simply switching to a "better" action or gamble at each successive return to a state. Key words and phrases: gambling problem, Markov decision process, strategy, stationary strategy, monotonically improving strategy, limit-optimal strategy
Novel CP-violating Effects in B decays from Charged-Higgs in a Two-Higgs Doublet Model for the Top Quark
We explore charged-Higgs cp-violating effects in a specific type III
two-Higgs doublet model which is theoretically attractive as it accommodates
the large mass of the top quark in a natural fashion. Two new CP-violating
phases arise from the right-handed up quark sector. We consider CP violation in
both neutral and charged B decays. Some of the important findings are as
follows. 1) Large direct-CP asymmetry is found to be possible for B+- to psi/J
K+-. 2) Sizable D-anti-D mixing effect at the percent level is found to be
admissible despite the stringent constraints from the data on K-anti-K mixing,
b to s gamma and B to tau nu decays. 3) A simple but distinctive CP asymmetry
pattern emerges in decays of B_d and B_s mesons, including B_d to psi/J K_S, D+
D-, and B_s to D_s+ D_s-, psi eta/eta^prime, psi/J K_S. 4) The effect of
D-anti-D mixing on the CP asymmetry in B+- to D/anti-D K+- and on the
extraction of the angle gamma of the unitarity triangle from such decays can be
significant.Comment: 32 pages, 5 figures, section V.A revised, version to appear in PR
Benford's law predicted digit distribution of aggregated income taxes: the surprising conformity of Italian cities and regions
The yearly aggregated tax income data of all, more than 8000, Italian
municipalities are analyzed for a period of five years, from 2007 to 2011, to
search for conformity or not with Benford's law, a counter-intuitive phenomenon
observed in large tabulated data where the occurrence of numbers having smaller
initial digits is more favored than those with larger digits. This is done in
anticipation that large deviations from Benford's law will be found in view of
tax evasion supposedly being widespread across Italy. Contrary to expectations,
we show that the overall tax income data for all these years is in excellent
agreement with Benford's law. Furthermore, we also analyze the data of
Calabria, Campania and Sicily, the three Italian regions known for strong
presence of mafia, to see if there are any marked deviations from Benford's
law. Again, we find that all yearly data sets for Calabria and Sicily agree
with Benford's law whereas only the 2007 and 2008 yearly data show departures
from the law for Campania. These results are again surprising in view of
underground and illegal nature of economic activities of mafia which
significantly contribute to tax evasion. Some hypothesis for the found
conformity is presented.Comment: 18 pages, 5 tables, 4 figures, 61 references, To appear in European
Physical Journal
Neutral top-pion and lepton flavor violating processes
In the context of topcolor-assisted techicolor(TC2) models, we study the
contributions of the neutral top-pion to the lepton flavor
violating(LFV) processes and .
We find that the present experimental bound on gives severe
constraints on the free parameters of models. Taking into account these
constraints, we consider the processes generated by
top-pion exchange at the tree-level and the one loop level, and obtain
, , in most of
the parameter space.Comment: latex files,16 pages, 6 figures. Submitted to Phys. Rev.
Observation of the screening signature in the lateral photovoltage of electrons in the Quantum Hall regime
The lateral photovoltage generated in the plane of a two-dimensional electron
system (2DES) by a focused light spot, exhibits a fine-structure in the quantum
oscillations in a magnetic field near the Quantum Hall conductivity minima. A
double peak structure occurs near the minima of the longitudinal conductivity
oscillations. This is the characteristic signature of the interplay between
screening and Landau quantization.Comment: 4 pages, 4 figures, to be published in Phys. Rev.
Rare Charm Decays in the Standard Model and Beyond
We perform a comprehensive study of a number of rare charm decays,
incorporating the first evaluation of the QCD corrections to the short distance
contributions, as well as examining the long range effects. For processes
mediated by the transitions, we show that sensitivity to
short distance physics exists in kinematic regions away from the vector meson
resonances that dominate the total rate. In particular, we find that
and are sensitive to non-universal
soft-breaking effects in the Minimal Supersymmetric Standard Model with
R-parity conservation. We separately study the sensitivity of these modes to
R-parity violating effects and derive new bounds on R-parity violating
couplings. We also obtain predictions for these decays within extensions of the
Standard Model, including extensions of the Higgs, gauge and fermion sectors,
as well as models of dynamical electroweak symmetry breaking.Comment: 45 pages, typos fixed, discussions adde
Direct Top Quark Production at Hadron Colliders as a Probe of New Physics
We examine the effect of an anomalous flavor changing chromomagnetic moment
which allows direct top quark production (two partons combining into an
unaccompanied single top quark in the s-channel) at hadron colliders. We
consider both t-c-g and t-u-g couplings. We find that the anomalous charm quark
coupling parameter can be measured down to ) at the Tevatron with the Main Injector upgrade(LHC).
The anomalous up quark coupling parameter can be measured
to ) at the Tevatron(LHC).Comment: 14 pages, Latex, requires feynm
Dynamical Left-Right Symmetry Breaking
We study a left--right symmetric model which contains only elementary gauge
boson and fermion fields and no scalars. The phenomenologically required
symmetry breaking emerges dynamically leading to a composite Higgs sector with
a renormalizable effective Lagrangian. We discuss the pattern of symmetry
breaking and phenomenological consequences of this scenario. It is shown that a
viable top quark mass can be achieved for the ratio of the VEVs of the
bi--doublet =~ 1.3--4. For a theoretically
plausible choice of the parameters the right--handed scale can be as low as
; in this case one expects several intermediate and low--scale
scalars in addition to the \SM Higgs boson. These may lead to observable lepton
flavour violation effects including decay with the rate close
to its present experimental upper bound.Comment: 51 pages, LaTeX and uuencoded, packed Postscript figures. The
complete paper, including figures, is also available via WWW at
http://www.cip.physik.tu-muenchen.de/tumphy/d/T30d/PAPERS/
TUM-HEP-222-95.ps.g
Top-Quark Decay Via the Anomalous Coupling at Hadron Colliders
We determine the constraints on the anomalous top-quark coupling associated
with the flavor-changing neutral current vertex from the
limits on the -quark rare decay and non-standard
top-quark decays. Based on these constraints, we discuss the experimental
observability of the rare decay mode , both at the
Fermilab Tevatron with a luminosity-upgrade and at the LHC.Comment: 19 pages, 8 figures, RevTeX, postscript files available via anonymous
ftp: ftp://ucdhep.ucdavis.edu/han/top/ (get paper_top.ps and fig*.ps
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