4,499 research outputs found
Studies of Neutrino-Electron Scattering at the Kuo-Sheng Reactor Neutrino Laboratory
Studies on electron antineutrino-electron elastic scattering were performed
using a 200-kg CsI(Tl) scintillating crystal detector array at the Kuo-Sheng
Nuclear Power Plant in Taiwan. The measured cross section of R(exp) = [1.00 +-
0.32(stat)]xR(SM) is consistent with the Standard Model expectation and the
corresponding weak mixing angle derived is sin2T = 0.24 +- 0.05 (stat). The
results are consistent with a destructive interference effect between neutral
and charged-currents in this process. Limits on neutrino magnetic moment of
mu(nu_(e)) < 2.0 x 10^(-10) mu_(B) at 90% confidence level and on electron
antineutrino charge radius of r^(2) < (0.12 +- 2.07)x10^(-32) cm^2 were also
derived.Comment: Parallel talk at ICHEP08, Philadelphia, USA, July 2008. 4 pages,
LaTex, 4 eps figure
Final results of nu-e-bar electron scattering cross-section measurements and constraints on new physics
The nu-e-bar electron elastic scattering cross-section was measured with a
CsI(Tl) scintillating crystal detector array with a total mass of 187 kg at the
Kuo-Sheng Nuclear Power Station. The detectors were exposed to a reactor
nu-e-bar flux of 6.4 X 10^{12} cm^{-2}s^{-1} originated from a core with 2.9 GW
thermal power. Using 29882/7369 kg-days of Reactor ON/OFF data, the Standard
Model (SM) of electroweak interaction was probed at the 4-momentum transfer
range of Q^2 ~ 3 X 10^{-6} GeV^2. A cross-section ratio of R_{expt} = [1.08 +-
0.21(stat) +- 0.16(sys)] X R_{SM} was measured. Constraints on the electroweak
parameters (g_V,g_A) were placed, corresponding to a weak mixing angle
measurement of \s2tw = [0.251 +- 0.031(stat) +- 0.024(sys)]. Destructive
interference in the SM nu-e-bar+e processes was verified. Bounds on neutrino
anomalous electromagnetic properties (neutrino magnetic moment and neutrino
charge radius), non-standard neutrino interactions, upparticle physics and
non-commutative physics were placed. We summarize the experimental details and
results, and discuss projected sensitivities with realistic and feasible
hardware upgrades.Comment: 4 pages, 4 figures, 2 tables ; To appear in Proceedings of TAUP-2011
Conferenc
Distortion Minimization in Gaussian Layered Broadcast Coding with Successive Refinement
A transmitter without channel state information (CSI) wishes to send a
delay-limited Gaussian source over a slowly fading channel. The source is coded
in superimposed layers, with each layer successively refining the description
in the previous one. The receiver decodes the layers that are supported by the
channel realization and reconstructs the source up to a distortion. The
expected distortion is minimized by optimally allocating the transmit power
among the source layers. For two source layers, the allocation is optimal when
power is first assigned to the higher layer up to a power ceiling that depends
only on the channel fading distribution; all remaining power, if any, is
allocated to the lower layer. For convex distortion cost functions with convex
constraints, the minimization is formulated as a convex optimization problem.
In the limit of a continuum of infinite layers, the minimum expected distortion
is given by the solution to a set of linear differential equations in terms of
the density of the fading distribution. As the bandwidth ratio b (channel uses
per source symbol) tends to zero, the power distribution that minimizes
expected distortion converges to the one that maximizes expected capacity.
While expected distortion can be improved by acquiring CSI at the transmitter
(CSIT) or by increasing diversity from the realization of independent fading
paths, at high SNR the performance benefit from diversity exceeds that from
CSIT, especially when b is large.Comment: Accepted for publication in IEEE Transactions on Information Theor
Constraints on Dark Photon from Neutrino-Electron Scattering Experiments
A possible manifestation of an additional light gauge boson , named
as Dark Photon, associated with a group is studied in neutrino
electron scattering experiments. The exclusion plot on the coupling constant
and the dark photon mass is obtained. It is shown
that contributions of interference term between the dark photon and the
Standard Model are important. The interference effects are studied and compared
with for data sets from TEXONO, GEMMA, BOREXINO, LSND as well as CHARM II
experiments. Our results provide more stringent bounds to some regions of
parameter space.Comment: 22 pages, 6 figures, 2 tables, text improved, fig.6 updated,
references adde
Minimum Expected Distortion in Gaussian Layered Broadcast Coding with Successive Refinement
A transmitter without channel state information (CSI) wishes to send a
delay-limited Gaussian source over a slowly fading channel. The source is coded
in superimposed layers, with each layer successively refining the description
in the previous one. The receiver decodes the layers that are supported by the
channel realization and reconstructs the source up to a distortion. In the
limit of a continuum of infinite layers, the optimal power distribution that
minimizes the expected distortion is given by the solution to a set of linear
differential equations in terms of the density of the fading distribution. In
the optimal power distribution, as SNR increases, the allocation over the
higher layers remains unchanged; rather the extra power is allocated towards
the lower layers. On the other hand, as the bandwidth ratio b (channel uses per
source symbol) tends to zero, the power distribution that minimizes expected
distortion converges to the power distribution that maximizes expected
capacity. While expected distortion can be improved by acquiring CSI at the
transmitter (CSIT) or by increasing diversity from the realization of
independent fading paths, at high SNR the performance benefit from diversity
exceeds that from CSIT, especially when b is large.Comment: To appear in the proceedings of the 2007 IEEE International Symposium
on Information Theory, Nice, France, June 24-29, 200
Stuck in the twilight zone? March 2019 municipal elections in Turkey
After 16 years of Tayyip Erdoğan in power and with almost total control of the bureaucracy and the mainstream media, it has become hard to imagine a Turkey in which he and his party, the Justice and Development Party (AKP), would not win an election. Yet, after a long nail-biter of an election night, Turkey woke up on April 1 to results indicating a major shift: Defying expectations, Turkish voters had delivered a challenge to the dominance of the governing coalition. While this came as a surprise to some, it points to growing discontent among voters that was able to find expression through institutional means. This was made possible by various parts of the opposition that ran effective alliance strategies and campaigns as well as the election-night process. This accomplishment of the opposition, however, does not necessarily mean an easy shift to a democratic path in Turkey. Much depends on how various actors in the governing coalition respond to this new picture. (Autorenreferat
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