34,034 research outputs found
Tracing the magnetic field morphology of the Lupus I molecular cloud
Deep R-band CCD linear polarimetry collected for fields with lines-of-sight
toward the Lupus I molecular cloud is used to investigate the properties of the
magnetic field within this molecular cloud. The observed sample contains about
7000 stars, almost 2000 of them with polarization signal-to-noise ratio larger
than 5. These data cover almost the entire main molecular cloud and also sample
two diffuse infrared patches in the neighborhood of Lupus I. The large scale
pattern of the plane-of-sky projection of the magnetic field is perpendicular
to the main axis of Lupus I, but parallel to the two diffuse infrared patches.
A detailed analysis of our polarization data combined with the Herschel/SPIRE
350 um dust emission map shows that the principal filament of Lupus I is
constituted by three main clumps acted by magnetic fields having different
large-scale structure properties. These differences may be the reason for the
observed distribution of pre- and protostellar objects along the molecular
cloud and its apparent evolutive stage. On the other hand, assuming that the
magnetic field is composed by a large-scale and a turbulent components, we find
that the latter is rather similar in all three clumps. The estimated
plane-of-sky component of the large-scale magnetic field ranges from about 70
uG to 200 uG in these clumps. The intensity increases towards the Galactic
plane. The mass-to-magnetic flux ratio is much smaller than unity, implying
that Lupus I is magnetically supported on large scales.Comment: 10 pages, 9 figures. Accepted for publication in Ap
The 750 GeV -cion: Where else should we look for it?
The resonance at GeV in the diphoton channel observed by ATLAS
and CMS, if it holds up, is almost certainly the ()cion of a larger dynasty
in a UV completion that may very well be connected to the hierarchy problem. At
this stage, however, an effective field theory framework provides a useful way
to parametrize searches for this resonance in other channels. Assuming that the
excess is due to a new scalar or pseudoscalar boson, we study associated
production of ("-strahlung") at the LHC and propose searches in several
clean channels like , \gamma\gamma\ell\eslash and
\ell\ell\ell\gamma\eslash to probe dimension-5 operators coupling to
Standard Model gauge bosons. We consider a range of widths for , from 5 GeV
to 45 GeV, and find that the three channels probe complementary regions of
parameter space and the suppression scale . The finding of most
immediate relevance is that with 3 fb, the LHC might already reveal new
excesses in the channel and a 5(3) discovery
may already be possible after collecting 65(25) fb of data with
\ell\ell\ell\gamma\eslash events if the scale of the new physics is within
9 TeV for couplings respecting 8 TeV LHC bounds and compatible with the
observed excess in diphotons for a wide resonance as suggested by the ATLAS
Collaboration. Beyond the EFT parametrization, we found realizations of models
with heavy vector-like quarks and leptons which can simultaneously fit the
diphoton excess and be discovered in the channels proposed here.Comment: 11 pages, 2 tables, 5 figures. References and comments added. Version
accepted for publication in Physics Letters
- …