6,598 research outputs found
RS resonance in di-final state production at the LHC to NLO+PS accuracy
We study the di-final state processes (, ,
, ) to NLO+PS accuracy, as a result of both the SM and RS
Kaluza-Klein graviton excitations. Decay of the electroweak gauge boson final
states to different leptonic states are included at the showering stage. A
selection of the results has been presented with PDF and scale uncertainties
for various distributions. Using the di-lepton and di-photon final states, we
present the search sensitivity, for the TeV LHC at fb
luminosity.Comment: 20 pages, 14 figure
The synthesis of a symmetrically substituted α-octa(isopentoxy)anthralocyanine
α-Octa(isopentoxy)anthralocyanine has been synthesized and is found to have an unprecedented low-energy Q-band absorption and a low first oxidation potential
Three-body rf association of Efimov trimers
We present a theoretical analysis of rf association of Efimov trimers in a
2-component Bose gas with short-range interactions. Using the adiabatic
hyperspherical Green's function formalism to solve the quantum 3-body problem,
we obtain universal expressions for 3-body rf association rates as a function
of the s-wave scattering length . We find that the association rates scale
as in the limit of large , and diverge as whenever
an Efimov state crosses the atom-dimer threshold (where stands for the
atom-dimer scattering length). Our calculations show that trimer formation
rates as large as cm/s can be achieved with rf Rabi
frequencies of order 1 MHz, suggesting that direct rf association is a powerful
tool of making and probing few-body quantum states in ultracold atomic gases.Comment: 4 pages, 2 figure
Quantum Pumping with Ultracold Atoms on Microchips: Fermions versus Bosons
We present a design for simulating quantum pumping of electrons in a
mesoscopic circuit with ultra-cold atoms in a micro-magnetic chip trap. We
calculate theoretical results for quantum pumping of both bosons and fermions,
identifying differences and common features, including geometric behavior and
resonance transmission. We analyze the feasibility of experiments with bosonic
Rb and fermionic K atoms with an emphasis on reliable atomic
current measurements.Comment: 4 pages; 4 figure
Inverse Compton scattering on solar photons, heliospheric modulation, and neutrino astrophysics
We study the inverse Compton scattering of solar photons by Galactic
cosmic-ray electrons. We show that the gamma-ray emission from this process is
substantial with the maximum flux in the direction of the Sun; the angular
distribution of the emission is broad. This previously-neglected foreground
should be taken into account in studies of the diffuse Galactic and
extragalactic gamma-ray emission. Furthermore, observations by GLAST can be
used to monitor the heliosphere and determine the electron spectrum as a
function of position from distances as large as Saturn's orbit to close
proximity of the Sun, thus enabling unique studies of solar modulation. This
paves the way for the determination of other Galactic cosmic-ray species,
primarily protons, near the solar surface which will lead to accurate
predictions of gamma rays from pp-interactions in the solar atmosphere. These
albedo gamma rays will be observable by GLAST, allowing the study of deep
atmospheric layers, magnetic field(s), and cosmic-ray cascade development. The
latter is necessary to calculate the neutrino flux from pp-interactions at
higher energies (>1 TeV). Although this flux is small, it is a "guaranteed
flux" in contrast to other astrophysical sources of neutrinos, and may be
detectable by km^3 neutrino telescopes of the near future, such as IceCube.
Since the solar core is opaque for very high-energy neutrinos, directly
studying the mass distribution of the solar core may thus be possible.Comment: 4 pages, 4 figures, emulateapj.cls, final version; published in ApJ
Letters, added an erratum; conclusions unchange
Drell-Yan, ZZ, W+W- production in SM & ADD model to NLO+PS accuracy at the LHC
In this paper, we present the next-to-leading order QCD corrections for
di-lepton, di-electroweak boson (ZZ, W+W-) production in both the SM and the
ADD model, matched to the HERWIG parton-shower using the aMC@NLO framework. A
selection of results at the 8 TeV LHC, which exhibits deviation from the SM as
a result of the large extra-dimension scenario are presented.Comment: 12 pages, 10 figures, search sensitivity for the 14 TeV LHC
discussed, version to appear in Eur. Phys. J.
Teenage Childbearing and Its Life Cycle Consequences: Exploiting a Natural Experiment
In this paper, we exploit a 'natural experiment' associated with human reproduction to identify the effect of teen childbearing on subsequent educational attainment, family structure, labor market outcomes and financial self-sufficiency. In particular, we exploit the fact that a substantial fraction of women who become pregnant experience a miscarriage (spontaneous abortion) and thus do not have a birth. If miscarriages were purely random and if miscarriages were the only way, other than by live births, that a pregnancy ended, then women, who had a miscarriage as a teen, would constitute an ideal control group with which to contrast teenage mothers. Exploiting this natural experiment, we devise an Instrumental Variables (IV) estimators for the consequences of teen mothers not delaying their childbearing, using data from the National Longitudinal Survey of Youth, 1979 (NLSY79). Our major finding is that many of the negative consequences of not delaying childbearing until adulthood are much smaller than has been estimated in previous studies. While we do find adverse consequences of teenage childbearing immediately following a teen mother's first birth, these negative consequences appear short- lived. By the time a teen mother reachers her late twenties, she appears to have only slightly more children, is only slightly more likely to be single mother, and has no lower levels of educational attainment than if she had delayed her childbearing to adulthood. In fact, by this age teen mothers appear to be better off in some aspects of their lives. Teenage childbearing appears to raise levels of labor supply, accumulated work experience and labor market earnings and appears to reduce the chances of living in poverty and participating in the associated social welfare programs. These estimated effects imply that the cost of teenage childbearing to U.S. taxpayers is negligible. In particular, our estimates imply that the widely held view that teenage childbearing imposes a substantial cost on government is an artifact of the failure to appropriately account for pre- existing socioeconomic differences between teen mothers and other women when estimating the causal effects of early childbearing. While teen mothers are very likely to live in poverty and experience other forms of adversity, our results imply that little of this would be changed just by getting teen mothers to delay their childbearing into adulthood.
Developing the Galactic diffuse emission model for the GLAST Large Area Telescope
Diffuse emission is produced in energetic cosmic ray (CR) interactions,
mainly protons and electrons, with the interstellar gas and radiation field and
contains the information about particle spectra in distant regions of the
Galaxy. It may also contain information about exotic processes such as dark
matter annihilation, black hole evaporation etc. A model of the diffuse
emission is important for determination of the source positions and spectra.
Calculation of the Galactic diffuse continuum gamma-ray emission requires a
model for CR propagation as the first step. Such a model is based on theory of
particle transport in the interstellar medium as well as on many kinds of data
provided by different experiments in Astrophysics and Particle and Nuclear
Physics. Such data include: secondary particle and isotopic production cross
sections, total interaction nuclear cross sections and lifetimes of radioactive
species, gas mass calibrations and gas distribution in the Galaxy (H_2, H I, H
II), interstellar radiation field, CR source distribution and particle spectra
at the sources, magnetic field, energy losses, gamma-ray and synchrotron
production mechanisms, and many other issues. We are continuously improving the
GALPROP model and the code to keep up with a flow of new data. Improvement in
any field may affect the Galactic diffuse continuum gamma-ray emission model
used as a background model by the GLAST LAT instrument. Here we report about
the latest improvements of the GALPROP and the diffuse emission model.Comment: 2 pages, 2 figures; to appear in the Proc. of the First Int. GLAST
Symp. (Stanford, Feb. 5-8, 2007), eds. S.Ritz, P.F.Michelson, and C.Meegan,
AIP Conf. Pro
- …