974 research outputs found
Muonic Hydrogen and the Third Zemach Moment
We determine the third Zemach moment of hydrogen (_(2)) using only the
world data on elastic electron-proton scattering. This moment dominates the O
(Z alpha)^5 hadronic correction to the Lamb shift in muonic atoms. The
resulting moment, _(2) = 2.71(13) fm^3, is somewhat larger than
previously inferred values based on models. The contribution of that moment to
the muonic hydrogen 2S level is -0.0247(12) meV.Comment: 3 pages, no figures, revtex - submitted to Physical Review
Is simultaneous and --scaling in the quasi-elastic region accidental?
We study the and --scaling of the nuclear response at large momentum
transfer in order to understand how scaling based on very different
descriptions of the elementary interaction can occur simultaneously. We find
that the approximate validity of -scaling at low energy loss arises from
the coincidental behavior of the quasielastic and deep inelastic cross
sections.Comment: 4 pages, 3 Postscript figure
Start-ups as technology life cycle indicator for the early stage of application: An analysis of the battery value chain
© 2018 Elsevier Ltd Insights from battery research and development (R&D) need to be transferred into industrial application to create innovations and thus foster e.g. electro mobility. In terms of battery technology transfer, the early phase of application is particularly challenging due to the close intertwining between R&D and application. Therefore, the present study introduces start-ups as an additional indicator to capture the transition from science to industry within the technology life cycle. The findings show that despite highly dynamic R&D activities, technology transfer is only taking place on a very limited level. Surprisingly, start-ups focus on incremental improvements of existing technologies instead of introducing radical breakthrough-technologies. An analysis of the battery value chain reveals that opportunities for start-ups are rather located downstream in the value chain when integrating cells to battery systems and developing applications relying on innovative battery technologies. The findings contribute to the area of technology life cycle analysis explicitly using start-up companies as additional indicator for the critical transfer step from R&D to application. In a similar vein, technology forecasting literature, which is to date mainly focused on R&D, is expanded by a more application-centred perspective that allows identifying transfer opportunities along the technology value chain
Using Electron Scattering Superscaling to predict Charge-changing Neutrino Cross Sections in Nuclei
Superscaling analyses of few-GeV inclusive electron scattering from nuclei
are extended to include not only quasielastic processes, but now also into the
region where -excitation dominates. It is shown that, with reasonable
assumptions about the basic nuclear scaling function extracted from data and
information from other studies of the relative roles played by correlation and
MEC effects, the residual strength in the resonance region can be accounted for
through an extended scaling analysis. One observes scaling upon assuming that
the elementary cross section by which one divides the residual to obtain a new
scaling function is dominated by the transition and employing a
new scaling variable which is suited to the resonance region. This yields a
good representation of the electromagnetic response in both the quasielastic
and regions. The scaling approach is then inverted and predictions are
made for charge-changing neutrino reactions at energies of a few GeV, with
focus placed on nuclei which are relevant for neutrino oscillation
measurements. For this a relativistic treatment of the required weak
interaction vector and axial-vector currents for both quasielastic and
-excitation processes is presented.Comment: 42 pages, 9 figures, accepted for publication in Physical Review
Lamb Shift in Light Muonic Atoms - Revisited
In connection with recent and proposed experiments, and new theoretical
results, my previous calculations of the Lamb shift in muonic hydrogen will be
reviewed and compared with other work. In addition, numerical results for
muonic deuterium and helium will be presented. Some previously neglected (but
very small) effects are included.Comment: 41 pages. This paper has appeared in Annals of Physics, vol. 327, pp
733-763 (2012). The present version has corrected several misprints, and
updated some references to take into account new result
On the dependence of the wave function of a bound nucleon on its momentum and the EMC effect
It is widely discussed in the literature that the wave function of the
nucleon bound in a nucleus is modified due to the interaction with the
surrounding medium. We argue that the modification should strongly depend on
the momentum of the nucleon. We study such an effect in the case of the
point-like configuration component of the wave function of a nucleon bound in a
nucleus A, considering the case of arbitrary final state of the spectator A-1
system. We show that for non relativistic values of the nucleon momentum, the
momentum dependence of the nucleon deformation appears to follow from rather
general considerations and discuss the implications of our theoretical
observation for two different phenomena: i) the search for medium induced
modifications of the nucleon radius of a bound nucleon through the measurement
of the electromagnetic nucleon form factors via the A(e,e'p)X process, and ii)
the A-dependence of the EMC effect; in this latter case we also present a new
method of estimating the fraction of the nucleus light-cone momentum carried by
the photons and find that in a heavy nuclei protons loose about 2% of their
momentum.Comment: 38 pages, 1 figure; changed references and text in Section I
(Introduction
Collisional Quenching of High Rotational Levels in A_2_+ OH
Collisional removal of the v_=0 level of the A_2_+ state of the OH radical has been studied as a function of rotational level N_ at room temperature. OH in high rotational levels of the X_2_i state were created by 193 nm photolysis of HNO3 and excited to A_2_+ by a tunable dye laser. Time decays of fluorescence at varying pressures were measured. For O2 and H2, the quenching cross section _Q decreased with increasing N_ until N__10; for higher N_ it appears to remain approximately constant. Xe behaves the same way except that the decrease continues to N_=15. For Kr, _Q appears to decrease to within experimental error of zero at N_=10; and for N2 it was within error of zero above N_=10. These results have implications for laser-induced fluorescence atmospheric monitoring of OH and combustion temperature determinations, as well as a fundamental understanding of collisional quenching. Quenching of OH, N__1, by HNO3 was found to be 81±8 A2.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86761/1/Sick30.pd
Monitoring change in cycling with the Danish bike- traffic index.
The Danish Road Directorate has long experience in planning for cycling and the use of bicycle data and indexes. A national cycling index, a bike-traffic-index, was established in 1985, based on bike-flows continuously counted in locations all over the country. The number of counting stations included in the index has been increased over time to improve reliability and allow support for the development and assessment of policies aiming to maintain and further increase cycling. The index is partly fed by the Road Directorate and partly by the municipalities. With its current 61 counting stations in operation, the bike- traffic-index is still ‘thin’ compared to the equivalent car-traffic index, but it does provide consistent evidence on changes in cycling on Danish roads. The paper compares the bike-traffic-index with travel- survey data as indicators of changes in cycling, it presents the methodology and accuracy of the bike-traffic- index, and finally, it discusses its desirable improvements to increase accuracy and detect changes in cycling beyond the fluctuations in weather conditions that are generally important to cycling but also beyond policy reach
Probing Correlated Ground States with Microscopic Optical Model for Nucleon Scattering off Doubly-Closed-Shell Nuclei
The RPA long range correlations are known to play a significant role in
understanding the depletion of single particle-hole states observed in (e, e')
and (e, e'p) measurements. Here the Random Phase Approximation (RPA) theory,
implemented using the D1S force is considered for the specific purpose of
building correlated ground states and related one-body density matrix elements.
These may be implemented and tested in a fully microscopic optical model for NA
scattering off doubly-closed-shell nuclei. A method is presented to correct for
the correlations overcounting inherent to the RPA formalism. One-body density
matrix elements in the uncorrelated (i.e. Hartree-Fock) and correlated (i.e.
RPA) ground states are then challenged in proton scattering studies based on
the Melbourne microscopic optical model to highlight the role played by the RPA
correlations. Effects of such correlations which deplete the nuclear matter at
small radial distance (r 2 fm) and enhance its surface region, are getting
more and more sizeable as the incident energy increases. Illustrations are
given for proton scattering observables measured up to 201 MeV for the
O, Ca, Ca and Pb target nuclei. Handling the RPA
correlations systematically improves the agreement between scattering
predictions and data for energies higher than 150 MeV.Comment: 20 pages, 7 figure
y scaling in electron-nucleus scattering
Data on inclusive electron scattering from A = 4, 12, 27, 56, 197 nuclei at large momentum transfer are presented and analyzed in terms of y scaling. We find that the data do scale for y 1), and we study the convergence of the scaling function with the momentum transfer Q^2 and A
- …