772 research outputs found
Rotational Cooling of Polar Molecules by Stark-tuned Cavity Resonance
A general scheme for rotational cooling of diatomic heteronuclear molecules
is proposed. It uses a superconducting microwave cavity to enhance the
spontaneous decay via Purcell effect. Rotational cooling can be induced by
sequentially tuning each rotational transition to cavity resonance, starting
from the highest transition level to the lowest using an electric field.
Electrostatic multipoles can be used to provide large confinement volume with
essentially homogeneous background electric field.Comment: 10 pages, 6 figure
Spatial Periodicity of Galaxy Number Counts, CMB Anisotropy, and SNIa Hubble Diagram Based on the Universe Accompanied by a Non-Minimally Coupled Scalar Field
We have succeeded in establishing a cosmological model with a non-minimally
coupled scalar field that can account not only for the spatial
periodicity or the {\it picket-fence structure} exhibited by the galaxy -
relation of the 2dF survey but also for the spatial power spectrum of the
cosmic microwave background radiation (CMB) temperature anisotropy observed by
the WMAP satellite. The Hubble diagram of our model also compares well with the
observation of Type Ia supernovae. The scalar field of our model universe
starts from an extremely small value at around the nucleosynthesis epoch,
remains in that state for sufficiently long periods, allowing sufficient time
for the CMB temperature anisotropy to form, and then starts to grow in
magnitude at the redshift of , followed by a damping oscillation
which is required to reproduce the observed picket-fence structure of the
- relation. To realize such behavior of the scalar field, we have found
it necessary to introduce a new form of potential , with being a constant. Through this parameter ,
we can control the epoch at which the scalar field starts growing.Comment: 19 pages, 18 figures, Accepted for publication in Astrophysics &
Space Scienc
Numerical convergence of the block-maxima approach to the Generalized Extreme Value distribution
In this paper we perform an analytical and numerical study of Extreme Value
distributions in discrete dynamical systems. In this setting, recent works have
shown how to get a statistics of extremes in agreement with the classical
Extreme Value Theory. We pursue these investigations by giving analytical
expressions of Extreme Value distribution parameters for maps that have an
absolutely continuous invariant measure. We compare these analytical results
with numerical experiments in which we study the convergence to limiting
distributions using the so called block-maxima approach, pointing out in which
cases we obtain robust estimation of parameters. In regular maps for which
mixing properties do not hold, we show that the fitting procedure to the
classical Extreme Value Distribution fails, as expected. However, we obtain an
empirical distribution that can be explained starting from a different
observable function for which Nicolis et al. [2006] have found analytical
results.Comment: 34 pages, 7 figures; Journal of Statistical Physics 201
The Williams Scale of Attitude toward Paganism: development and application among British Pagans
This article builds on the tradition of attitudinal measures of religiosity established by Leslie Francis and colleagues with the Francis Scale of Attitude toward Christianity (and reflected in the Sahin-Francis Scale of Attitude toward Islam, the Katz-Francis Scale of Attitude toward Judaism, and the Santosh-Francis Scale of Attitude toward Hinduism) by introducing a new measure to assess the attitudinal disposition of Pagans. A battery of items was completed by 75 members of a Pagan Summer Camp. These items were reduced to produce a 21-item scale that measured aspects of Paganism concerned with: the God/Goddess, worshipping, prayer, and coven. The scale recorded an alpha coefficient of 0.93. Construct validity of the Williams Scale of Attitude toward Paganism was demonstrated by the clear association with measures of participation in private rituals
Mediating Solidarity
With the apparent increase in the number of alternative political media, political pluralists are again faced with the question: does the proliferation of subaltern counter-publics lead to a multiplication of forces? Fragmentation in political culture is fuelled by the rise of identity politics that focuses on consumption not production. Party allegiances and class alliances give way to more fluid and informal networks of action. Postmodern theorists celebrate fragmentation because it allows the recognition of diversity in political desires, acknowledges difference between individuals and debunks the myth of homogenous political units leading ultimately to liberation. But for political efficacy there must be more than the apparent freedom that comes with embracing difference and diversity. This article argues that if we accept the description of society as fragmented, in order to create a viable political community then solidarity is crucial. In a global economy, solidarity can be mediated through new communication technologies but the challenge is to articulate the politics online with actual movements and struggles on the ground
The PHENIX Experiment at RHIC
The physics emphases of the PHENIX collaboration and the design and current
status of the PHENIX detector are discussed. The plan of the collaboration for
making the most effective use of the available luminosity in the first years of
RHIC operation is also presented.Comment: 5 pages, 1 figure. Further details of the PHENIX physics program
available at http://www.rhic.bnl.gov/phenix
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt(s)=1.96 TeV using Lepton + Jets Events with Lifetime b-tagging
We present a measurement of the top quark pair () production cross
section () in collisions at TeV
using 230 pb of data collected by the D0 experiment at the Fermilab
Tevatron Collider. We select events with one charged lepton (electron or muon),
missing transverse energy, and jets in the final state. We employ
lifetime-based b-jet identification techniques to further enhance the
purity of the selected sample. For a top quark mass of 175 GeV, we
measure pb, in
agreement with the standard model expectation.Comment: 7 pages, 2 figures, 3 tables Submitted to Phys.Rev.Let
Search for a scalar or vector particle decaying into Zgamma in ppbar collisions at sqrt(s) = 1.96 TeV
We present a search for a narrow scalar or vector resonance decaying into
Zgamma with a subsequent Z decay into a pair of electrons or muons. The data
for this search were collected with the D0 detector at the Fermilab Tevatron
ppbar collider at a center of mass energy sqrt(s) = 1.96 TeV. Using 1.1 (1.0)
fb-1 of data, we observe 49 (50) candidate events in the electron (muon)
channel, in good agreement with the standard model prediction. From the
combination of both channels, we derive 95% C.L. upper limits on the cross
section times branching fraction (sigma x B) into Zgamma. These limits range
from 0.19 (0.20) pb for a scalar (vector) resonance mass of 600 GeV/c^2 to 2.5
(3.1) pb for a mass of 140 GeV/c^2.Comment: Published by Phys. Lett.
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