2,810 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.
Absolute frequency measurement of the 190mu and 194mu gas laser transitions
Absolute frequency measurements of 190 and 194 micron gas laser transition
Large 2HDM(II) one-loop corrections in leptonic tau decays
The one-loop contributions to the branching ratios for leptonic tau decays
are calculated in the CP conserving 2HDM(II). We found that these one-loop
contributions, involving both neutral and charged Higgs bosons, dominate over
the tree-level H^+ exchange, the latter one being totally negligible for the
decay into electron. The analysis is focused on large tanbeta enhanced
contributions to the considered branching ratios. We derive a simple analytical
expression for the one-loop contribution which holds in this case. We show that
the leptonic branching ratios of tau are complementary to the Higgsstrahlung
processes for h(H) and have a large potential on constraining parameters of the
model. In this work we provide upper limits on Yukawa couplings for both light
h and light A scenarios and we derive new lower limit on mass of M_{H^+} as a
function of tanbeta, which differs significantly from what was considered as
standard constraint based on the tree-level H^{+} exchange only. Interestingly
we obtain also an upper limit on M_{H^+}. For a SM-like h scenario, with heavy
and degenerate additional Higgs bosons, one-loop corrections disappear.Comment: 25 pgs. Figures and their descriptions improved, references adde
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
Complex flavour couplings in supersymmetry and unexpected CP-violation in the decay B -> phi K
Complex flavour couplings (off-diagonal mass terms) in the squark sector of
supersymmetric theories may drastically alter both the rate and the
CP-violating asymmetry of certain B-meson decays. We consider the effects of
couplings that induce b -> s transitions and lead to final state with
strangeness one. We investigate the bounds that must be satisfied by the new
terms and explore the possible implications on direct and mixing induced
asymmetries in the charged and neutral B -> J/Psi K and B -> phi K decays.Comment: 14 pages, 3 figure
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
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