3,169 research outputs found
Two-dimensional oscillating airfoil test apparatus
A two dimensional oscillating airfoil test apparatus is presented as a method of measuring unsteady aerodynamic forces on an airfoil or rotor blade section. The oscillating airfoil test rig, which is being built for use in an 11 X 11-foot transonic wind tunnel (speed range M = 0.4 - 1.4), will allow determination of unsteady loadings and detailed pressure distributions on representative airfoil sections undergoing simulated pitching and flapping motions. The design details of the motion generating system and supporting structure are presented. This apparatus is now in the construction phase
Directional Detection of Dark Matter with MIMAC
Directional detection is a promising search strategy to discover galactic
Dark Matter. We present a Bayesian analysis framework dedicated to Dark Matter
phenomenology using directional detection. The interest of directional
detection as a powerful tool to set exclusion limits, to authentify a Dark
Matter detection or to constrain the Dark Matter properties, both from particle
physics and galactic halo physics, will be demonstrated. However, such results
need highly accurate track reconstruction which should be reachable by the
MIMAC detector using a dedicated readout combined with a likelihood analysis of
recoiling nuclei.Comment: 4 pages, 2 figures, to appear in the proceedings of the TAUP 2011
conference held in Munich (5 - 9 September, 2011
Consistent two--dimensional chiral gravity
We study chiral induced gravity in the light-cone gauge and show that the
theory is consistent for a particular choice of chiralities. The corresponding
Kac--Moody central charge has no forbidden region of complex values.
Generalized analysis of the critical exponents is given and their relation to
the vacuum states is elucidated. All the parameters containing
information about the theory can be traced back to the characteristics of the
group of residual symmetry in the light--cone gauge.Comment: 38 pages, LateX, to appear in Int.J.Mod.Phys.
Getting beta-alpha without penguins
Oscillation effects in B0 -> Ks D0 and related processes are considered to
determine delta=beta-alpha+pi. We suggest that D0 decays to CP eigenstates used
in concert with inclusive D0 decays provide a powerful method for determining
delta cleanly i.e. without any complication from penguin processes. The CP
asymmetry is expected to be <=40% for D0 decays to non-CP eigenstates and <=80%
for decays to CP eigenstates. This method can lead to a fairly accurate
determination of delta with O(10^8-10^9) B-mesons.Comment: 4 pages 1 figure; Version 2: minor changes; references added; Some
changes in response to Referee Comment
Chiral corrections and lattice QCD results for fBs/fBd and (Delta ms/Delta md)
It has been argued recently that the inclusion of the chiral logarithms in
extrapolation of the lattice data can shift the value of the hadronic parameter
xi = (fBs sqrt(B_{Bs}))/(fBd sqrt(B_{Bd})), from 1.16(6) to 1.32(10) and even
higher. If true, that would considerably change the theoretical estimate for
the ratio of oscillation frequencies in the neutral Bs- and Bd-systems, and
would affect the standard CKM unitarity triangle analysis. In this letter we
show that (fBs/fBd) \approx (fK/fpi), and thus the uncertainty due to the
missing chiral logs is smaller than previously thought. By combining the NLO
chiral expansion with the static heavy quark limit we obtain xi = 1.22(8).Comment: Published versio
A Submillimeter HCN Laser in IRC+10216
We report the detection of a strong submillimeter wavelength HCN laser line
at a frequency near 805 GHz toward the carbon star IRC+10216. This line, the
J=9-8 rotational transition within the (04(0)0) vibrationally excited state, is
one of a series of HCN laser lines that were first detected in the laboratory
in the early days of laser spectroscopy. Since its lower energy level is 4200 K
above the ground state, the laser emission must arise from the inner part of
IRC+10216's circumstellar envelope. To better characterize this environment, we
observed other, thermally emitting, vibrationally excited HCN lines and find
that they, like the laser line, arise in a region of temperature approximately
1000 K that is located within the dust formation radius; this conclusion is
supported by the linewidth of the laser. The (04(0)0), J=9-8 laser might be
chemically pumped and may be the only known laser (or maser) that is excited
both in the laboratory and in space by a similar mechanism.Comment: 11 pages, 3 figure
A novel integral representation for the Adler function
New integral representations for the Adler D-function and the R-ratio of the
electron-positron annihilation into hadrons are derived in the general
framework of the analytic approach to QCD. These representations capture the
nonperturbative information encoded in the dispersion relation for the
D-function, the effects due to the interrelation between spacelike and timelike
domains, and the effects due to the nonvanishing pion mass. The latter plays a
crucial role in this analysis, forcing the Adler function to vanish in the
infrared limit. Within the developed approach the D-function is calculated by
employing its perturbative approximation as the only additional input. The
obtained result is found to be in reasonable agreement with the experimental
prediction for the Adler function in the entire range of momenta .Comment: 11 pages, 3 figure
Ubiquitous CP violation in a top-inspired left-right model
We explore CP violation in a Left-Right Model that reproduces the quark mass
and CKM rotation angle hierarchies in a relatively natural way by fixing the
bidoublet Higgs VEVs to be in the ratio m_b:m_t. Our model is quite general and
allows for CP to be broken by both the Higgs VEVs and the Yukawa couplings.
Despite this generality, CP violation may be parameterized in terms of two
basic phases. A very interesting feature of the model is that the mixing angles
in the right-handed sector are found to be equal to their left-handed
counterparts to a very good approximation. Furthermore, the right-handed
analogue of the usual CKM phase delta_L is found to satisfy the relation
delta_R \approx delta_L. The parameter space of the model is explored by using
an adaptive Monte Carlo algorithm and the allowed regions in parameter space
are determined by enforcing experimental constraints from the K and B systems.
This method of solution allows us to evaluate the left- and right-handed CKM
matrices numerically for various combinations of the two fundamental CP-odd
phases in the model. We find that all experimental constraints may be satisfied
with right-handed W and Flavour Changing Neutral Higgs masses as low as about 2
TeV and 7 TeV, respectively.Comment: 37 pages, 13 figure
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