3,950 research outputs found
Comments on ISR method in modern experiment and influence of final state radiation
We study the effect of final state radiation in the process , in the kinematical conditions of BaBar and BESIII experiment. We show
that this effect could be large, in particular in the low region ( is
the photon energy fraction) and should be taken into account.Comment: 8 pages, 5 figure
Two-component model for the axial form factor of the nucleon
The axial form factor of the nucleon is studied in a two-component model
consisting of a three-quark intrinsic structure surrounded by a meson cloud.
The experimental data in the space-like region are well reproduced with a
minimal number of parameters. The results are similar to those obtained from a
dipole fit up to 1 GeV, but they surprisingly show a zero between 2 and 3
GeV. Such behavior, predicted by the present model completely disagrees
with the dipole parametrization. The theoretical expression for the form factor
is then analytically extrapolated to the time-like region, giving the first
predictions in this regime. This kinematical region is especially interesting
for present and future colliders.Comment: 12 pages 2 figures Final version to appear in Phys. Rev.
Search for evidence of two photon contribution in elastic electron proton data
We reanalyze the most recent data on elastic electron proton scattering. We
look for a deviation from linearity of the Rosenbluth fit to the differential
cross section, which would be the signature of the presence of two photon
exchange. The two photon contribution is parametrized by a one parameter
formula, based on symmetry arguments. The present data do not show evidence for
such deviation.Comment: 15 pages 3 figures More details on the fitting procedure, more
explicit explanation
Asymptotics of the deuteron form factors in the nucleon model and JLab experiments
Using the instant form dynamics of Poincar\'e invariant quantum mechanics and
the modified relativistic impulse approximation proposed previously we
calculate asymptotics of electromagnetic form factors for the deuteron
considered as two--nucleon system. We show that today experiment on the elastic
-scattering has reached asymptotic regime. The possible range of momentum
transfer when the quark degrees of freedom could be seen in future JLab
experiments is estimated. The explicit relation between the behavior of
deuteron wave function at and the form factors asymptotics is obtained.
The conditions on wave functions to give the asymptotics predicted by QCD and
quark counting rules are formulated.Comment: 9 pages, 1 figur
Ground-based Raman-lidar for day and night measurements of water-vapor in the boundary layer
The solar-blind Raman-lidar based on a KrF laser (248 nm) developed at Lecceâs University (407 208 N, 187 68 E) is described. The lidar is currently used for day and night measurements of water vapor. The dependence of the measurement range of the lidar on the laser beam divergence is investigated and it is shown that the KrF laser beam divergence can be reduced by a factor A10 by using a quite
simple unstable cavity configuration. The maximum range which was limited to approximately 500 m for a A3 mrad divergence laser beam has increased up to 1200 m with a A0.3 mrad divergence laser beam since the field of view of the telescope was of 1 mrad. Water vapor profiles retrieved from lidar measurements under different operating conditions are presented. The effect of boundary-layer ozone absorption has also been investigated
Ive Got My Virtual Eye On You: Remote Proctors And Academic Integrity
This paper discusses the challenges of online teaching, the reasons students cheat and one means of curtailing that cheating in the online environment. The use of Securexam Remote Proctor System in one university application is reviewed
Direct radiative effects by anthropogenic particles at a polluted site: Rome (Italy)
The direct radiative effect (DRE) by all (anthropogenic plus natural) and anthropogenic aerosols is calculated at the solar (0.3â4 ÎŒm) and infrared (4â200 ÎŒm) spectral range to better address the annual cycle of the anthropogenic
aerosol impact at a site (Rome, Italy) significantly affected by pollution. Aerosol optical and microphysical properties from 2003 AERONET Sun/sky-photometer
measurements and solar surface albedos based on MODIS satellite sensor data constitute the necessary input to radiative transfer simulations. Clear- and all-sky
conditions are investigated by adopting ISCCP monthly products for high-, mid-, and low-cloud cover. It is shown that monthly mean values of aerosol optical depths by anthropogenic particles (AODa) are on average more than 50% of the corresponding all-aerosol-optical-depth (AOD) monthly means. In particular, the AODa/AOD ratio that varies within the (0.51â0.83) on autumn-winter (AW,
October-March), varies within the (0.50â0.71) range on spring-summer (SS, April-September) as a consequence of the larger contribution of natural particles on SS. The surface (sfc), all-sky DRE by anthropogenic particles that is negative all year round at solar wavelengths, represents on average 60% and 51% of the all-sky sfc-DRE by all aerosols
on AW and SS, respectively. The all-sky atmospheric forcing by anthropogenic particles (AFa) that is positive all year round, is little dependent on seasons: it varies within the (1.0â4.1)W/m2 and (2.0â4.2)W/m2 range on AW and SS, respectively. Conversely, the all-sky AF by all aerosols is characterized by a marked seasonality. As a consequence, the atmospheric forcing by anthropogenic particles that on average is 50% of the AF value on AW, decreases down to 36% of the AF value on SS. Infrared aerosol DREs that are positive all year round are significantly smaller than the corresponding absolute values of solar DREs. Clouds decrease on average ToA- and sfc-DRE absolute values by anthropogenic particles of 36% and 23%, respectively and are quite responsible of the seasonal dependence of aerosol forcing efficiencies by all and anthropogenic aerosols
Influence of Blackberry Plants on the Aroma Profile of Vitis vinifera L. cv. Pinot Noir
V. vinifera cv. Pinot noir vines were grown in pots together with blackberry plants and the effect of this association on the grape aroma was assessed. Preliminary data showed that vines that cohabited with blackberry had a different aroma profile compared to vine grown alone. The association with blackberry increased the concentration of 30 out 74 free aroma compounds and of 24 out 95 bound ones. No aroma compound was identified exclusively in the treated grapes
Discipline umanistiche e informatica. Quale futuro per l\u2019integrazione?
Social media and social networks, e-commerce and mobile are just a few,
common keywords of Web 2.0 that are driving a change in the process
of re-definition of professional profiles. Keywords, or even concepts,
which call for a broader reflection on the relationship between digital
technologies and humanities and on the social and economic impact
brought by the integration of heterogeneous skills. In the wake of Digital
Humanities a fluid approach to knowledge is revolutionizing the role of
cross-disciplinary approach to crafts related, in particular, to the Web
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