10,630 research outputs found
Mast flight system beam structure and beam structural performance
An overall understanding of the beam assembly and data with which potential experimenters can begin to conduct analyses relevant to their experiments is given. Data is given on the beam structural concept, the tip remote station layout, the intermediate remote station layout with and without actuators, beam element materials, equivalent beam characteristics, beam element properties, remote station mass properties, and MAST Flight System modal characteristics
Hybrid stars in the light of the massive pulsar PSR J1614-2230
We perform a systematic study of hybrid star configurations using several
parametrizations of a relativistic mean-field hadronic EoS and the NJL model
for three-flavor quark matter. For the hadronic phase we use the stiff GM1 and
TM1 parametrizations, as well as the very stiff NL3 model. In the NJL
Lagrangian we include scalar, vector and 't Hooft interactions. The vector
coupling constant is treated as a free parameter. We also consider that
there is a split between the deconfinement and the chiral phase transitions
which is controlled by changing the conventional value of the vacuum pressure
in the NJL thermodynamic potential by , being a free parameter. We find that, as we
increase the value of , hybrid stars have a larger maximum
mass but are less stable, i.e. hybrid configurations are stable within a
smaller range of central densities. For large enough , stable
hybrid configurations are not possible at all. The effect of increasing the
coupling constant is very similar. We show that stable hybrid
configurations with a maximum mass larger than the observed mass of the pulsar
PSR J1614-2230 are possible for a large region of the parameter space of
and provided the hadronic equation of state contains nucleons
only. When the baryon octet is included in the hadronic phase, only a very
small region of the parameter space allows to explain the mass of PSR
J1614-2230. We compare our results with previous calculations of hybrid stars
within the NJL model. We show that it is possible to obtain stable hybrid
configurations also in the case that corresponds to the
conventional NJL model for which the pressure and density vanish at zero
temperature and chemical potential.Comment: 7 pages, 5 figures; typos in Table 1 have been correcte
Coal Severance Taxes: A New Social Justice and Community/ Economic Development Tool for Coal-Producing Areas
One hundred eight-eight coal-producing counties in fifteen states were examined todetermine the relationship of coal severance tax allocations to community economicdevelopment and change in socio-economic conditions. The one hundred countiesreceiving coal severance taxes were identified as an experimental group\u27\u27 and theeighty-eight counties not receiving these funds were used as a control group\u27\u27 and theeighty-eight counties not receiving these funds were used as a control group in aquasi-experimental model. The five key socio-economic variables examined were (1)per capita income, (2) poverty rate, (3) employment growth, (4) unemployment rate,and (5) bank deposits. Coal counties which received coal severance tax allocationsand community economic development programs improved all five socio-economicconditions at a significantly higher rate than counties not benefitting from these dollarsand programs. Policy implications are discussed including the need to furtherexamine/refine coal and other resource taxation and reallocation programs of supportingrural community economic development
Isospin-breaking interactions studied through mirror energy differences
Background: Information on charge-dependent (i.e., isospin-non-conserving) interactions is extracted from excited states of mirror nuclei.
Purpose: Specifically, the purpose of the study is to extract effective isovector (Vpp 12Vnn) interactions which, in general, can either be of Coulomb or nuclear origin.
Methods: A comprehensive shell-model description of isospin-breaking effects is used to fit data on mirror energy differences in the A = 42\u201354 region. The angular-momentum dependence of isospin-breaking interactions was determined from a systematic study of mirror energy differences.
Results: The results reveal a significant isovector term, with a very strong spin dependence, beyond that expected of a two-body Coulomb interaction.
Conclusions: The isospin-breaking terms that are extracted have a J dependence that is not consistent with the known CSB properties of the bare nucleon-nucleon interaction
Probing new physics in diphoton production with proton tagging at the Large Hadron Collider
The sensitivities to anomalous quartic photon couplings at the Large Hadron
Collider are estimated using diphoton production via photon fusion. The tagging
of the protons proves to be a very powerful tool to suppress the background and
unprecedented sensitivities down to \gev are obtained,
providing a new window on extra dimensions and strongly-interacting composite
states in the multi-TeV range. Generic contributions to quartic photon
couplings from charged and neutral particles with arbitrary spin are also
presented.Comment: 4 pages, 3 figure
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