3,116 research outputs found
Vyvoj optimalnich algoritmu pro selekci ridkych semimionovych B rozpadu v detektoru ATLAS
In this thesis we propose the trigger algorithm for the semimuonic rare B decay selection in ATLAS experiment and we study its performance using the Monte Carlo sample of . The cut optimisation has been performed in order to obtain the optimal cut values and the signal rate for the process was estimated. The feasibility and performance of the tag-and-probe method for the calibration of di-muon triggers is investigated, too. Effects of the systematic uncertainties of the method on the measurements of J/ polarisation and the forward-backward asymmetry of were studied
The DEPFET Mini-matrix Particle Detector
The DEPFET is new type of active pixel particle detector. A MOSFET is integrated in each pixel, providing the first amplification stage of the readout electronics. Excellent noise parameters are obtained with this layout. The DEPFET detector will be integrated as an inner detector in the BELLE II and ILC experiment. A flexible measuring system with a wide control cycle range and minimal noise was designed for testing small detector prototypes.Noise of 60 electrons of the equivalent input charge was achieved during the first measurements on the system
Thermal Infrared Observations of Asteroid (99942) Apophis with Herschel
The near-Earth asteroid (99942) Apophis is a potentially hazardous asteroid.
We obtained far-infrared observations of this asteroid with the Herschel Space
Observatory's PACS instrument at 70, 100, and 160 micron. These were taken at
two epochs in January and March 2013 during a close Earth encounter. These
first thermal measurements of Apophis were taken at similar phase angles before
and after opposition. We performed a detailed thermophysical model analysis by
using the spin and shape model recently derived from applying a 2-period
Fourier series method to a large sample of well-calibrated photometric
observations. We find that the tumbling asteroid Apophis has an elongated shape
with a mean diameter of 375 m (of an equal volume sphere) and a
geometric V-band albedo of 0.30. We find a thermal inertia in
the range 250-800 JmsK (best solution at 600
JmsK), which can be explained by a mixture of low
conductivity fine regolith with larger rocks and boulders of high thermal
inertia on the surface. The thermal inertia, and other similarities with
(25143) Itokawa indicate that Apophis might also have a rubble-pile structure.
If we combine the new size value with the assumption of an Itokawa-like density
and porosity we estimate a mass between 4.4 and 6.2 10 kg which is more
than 2-3 times larger than previous estimates. We expect that the newly derived
properties will influence impact scenario studies and influence the long-term
orbit predictions of Apophis.Comment: Accepted for publication in Astronomy & Astrophysics, 21 pages, 8
figures, 2 table
Coping with the Climate Crisis: Exploring Art Therapy for Sustainable Mental Health
As devastating as the changes to the physical environment are, we have yet to fully grasp the mental health implications of the current climate crisis. Research has recently emerged which highlights specific mental health challenges linked to climate change. For example, eco-anxiety has been described as severe and habitual ecological worrying that does not lead to environmental activism or proactive behavior. Eco-grief includes feelings of powerlessness, helplessness, and an unresolved sense of loss related to the climate crisis. The current project adopted a theoretical methodology to explore how art therapy can address these mental health challenges. Data analysis included a systematic literature review, a critique of the literature, and a discussion of existing gaps. Eco-art therapy was suggested as a valuable therapeutic service which uniquely addresses the psychological impacts of the ecological crisis. The potential of eco-art therapy to facilitate creative expression, emotional exploration, as well as cultivate a connection with the natural environment was discussed. Furthermore, combining art therapy with nature-based therapies may facilitate engagement in pro-environmental behavior. Integrating art therapy and nature-based therapies may reduce mental health challenges associated with the climate crisis while playing a significant role in creating change.
Keywords: art therapy, climate change, climate crisis, mental health, eco-anxiety, eco-grief, sustainability, theoretical researc
Discovery, photometry, and astrometry of 49 classical nova candidates in M81 galaxy
This paper reports on a search for new classical nova candidates in the M81
galaxy based on archival, as well as recent, new images. We used images from
1999-2007 to search for optical transients in M81. The positions of the
identified classical nova candidates were used to study their spatial
distribution. Kolmogorov - Smirnov test (KS) and bottom-to-top (BTR) ratio
diagnostic were used to analyze the nova candidate distribution and
differentiate between the disk and the bulge populations. In total, 49
classical nova candidates were discovered. In this study, we present the
precise positions and photometry of these objects, plus the photometry of an
additional 9 classical nova candidates found by Neill and Shara (2004). With
our large sample, we find a different spatial distribution of classical nova
candidates when compared to the results of earlier studies. Also, an
extraordinarily bright nova was found and studied in detail.Comment: Accepted for publication in Astronomy & Astrophysics, 23 pages, 8
figure
The binary near-Earth asteroid (175706) 1996 FG3 - An observational constraint on its orbital evolution
Using our photometric observations taken between 1996 and 2013 and other
published data, we derived properties of the binary near-Earth asteroid
(175706) 1996 FG3 including new measurements constraining evolution of the
mutual orbit with potential consequences for the entire binary asteroid
population. We also refined previously determined values of parameters of both
components, making 1996 FG3 one of the most well understood binary asteroid
systems. We determined the orbital vector with a substantially greater accuracy
than before and we also placed constraints on a stability of the orbit.
Specifically, the ecliptic longitude and latitude of the orbital pole are
266{\deg} and -83{\deg}, respectively, with the mean radius of the uncertainty
area of 4{\deg}, and the orbital period is 16.1508 +/- 0.0002 h (all quoted
uncertainties correspond to 3sigma). We looked for a quadratic drift of the
mean anomaly of the satellite and obtained a value of 0.04 +/- 0.20 deg/yr^2,
i.e., consistent with zero. The drift is substantially lower than predicted by
the pure binary YORP (BYORP) theory of McMahon and Scheeres (McMahon, J.,
Scheeres, D. [2010]. Icarus 209, 494-509) and it is consistent with the theory
of an equilibrium between BYORP and tidal torques for synchronous binary
asteroids as proposed by Jacobson and Scheeres (Jacobson, S.A., Scheeres, D.
[2011]. ApJ Letters, 736, L19). Based on the assumption of equilibrium, we
derived a ratio of the quality factor and tidal Love number of Q/k = 2.4 x 10^5
uncertain by a factor of five. We also derived a product of the rigidity and
quality factor of mu Q = 1.3 x 10^7 Pa using the theory that assumes an elastic
response of the asteroid material to the tidal forces. This very low value
indicates that the primary of 1996 FG3 is a 'rubble pile', and it also calls
for a re-thinking of the tidal energy dissipation in close asteroid binary
systems.Comment: Many changes based on referees comment
Belle II Technical Design Report
The Belle detector at the KEKB electron-positron collider has collected
almost 1 billion Y(4S) events in its decade of operation. Super-KEKB, an
upgrade of KEKB is under construction, to increase the luminosity by two orders
of magnitude during a three-year shutdown, with an ultimate goal of 8E35 /cm^2
/s luminosity. To exploit the increased luminosity, an upgrade of the Belle
detector has been proposed. A new international collaboration Belle-II, is
being formed. The Technical Design Report presents physics motivation, basic
methods of the accelerator upgrade, as well as key improvements of the
detector.Comment: Edited by: Z. Dole\v{z}al and S. Un
Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV
The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration
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