9798249
A polarimetric study of the B[e] star HD 45677
We present new medium-resolution spectropolarimetric observations of HD 45677 in the B and R bands. A change in polarization is detected across Hα, Hβ and Hγ confirming that the ionized region around the star is aspherical. (Q, U) points associated with these emission lines occur away from the continuum, defining a polarization vector which points in the same direction for each of the lines at an average intrinsic polarization angle of 164°± 3°. 
 
 
 
These data were combined with past photometric and polarimetric data from the literature to investigate any variability. We find that HD 45677 is both photometrically and polarimetrically variable and that these changes are linked. We suggest that these variations may be caused by an aspherical blowout, and by deriving a least-squares fit to the B-band polarimetric data in the Q–U space, we show that the blowout occurs at an intrinsic polarization angle of 175°± 1°, along the same angle as the proposed geometry of the ionized region.
35843308
Spectropolarimetry of the massive post -Red Supergiants IRC +10420 and HD 179821
We present medium resolution spectropolarimetry and long term photo-polarimetry of two massive post-red supergiants, IRC +10420 and HD 179821. The data provide new information on their circumstellar material as well as their evolution. 
In IRC +10420, the polarization of the Ha line is different to that of the continuum, which indicates that the electron-scattering region is not spherically symmetric. The observed long term changes in the polarimetry can be associated with an axi-symmetric structure, along the short axis of the extended reflection nebulosity. Long term photometry reveals that the star increased in temperature until the mid-nineties, after which the photospheric flux in the optical levelled off. As the photometric changes are mostly probed in the red, they do not trace high stellar temperatures sensitively. And so, it is not obvious whether the star has halted its increase in temperature or not. For HD 179821 we find no polarization effects across any absorption or emission lines, but observe very large polarization changes of order 5% over 15 years. During the same period, the optical photometry displayed modest variability at the 0.2 magnitude level. This is unexpected, because large polarization changes are generally accompanied by 
strong photometric changes. Several explanations for this puzzling fact are discussed. Most of which, involving asymmetries in the circumstellar material, seem to fail as there is no evidence for the presence of hot, dusty material close to the star. A caveat is that the sparsely available near-infrared photometry could have missed periods of strong polarization activity. Alternatively, the variations can be explained by the presence of a non-radially pulsating photosphere. Changes in the photometry hint at an 
increase in temperature corresponding to a change through two spectral subclasses over the past ten years.
178365536
Tracking Chamber Data from PLASTEX: Instrumental Performance for Single Particles
120390470
STAR CLUSTER: a tracking array for gamma-ray astronomy
SummaryA new type of extensive air shower array-telescope is being constructed, close to the GREX scintillator array at Haverah Park. The design of the new instrument is based on identification and measurement of individual shower particles by means of pattern recognition techniques applied to data from LST chambers above and below a thin sheet of high-Z material. Air showers will be detected in the range from 1014 eV to 1018 eV. The directions of the shower primaries will be reconstructed with an accuracy of a few tenths of a degree using triangulation between tracks of detected shower particles: >1 GeV electrons, photons and muons. Particle densities measured at the detector locations will be used to calculate shower sizes and core locations. Information about the height of production of the high-energy secondaries will be obtained for each shower. This information will be taken into account in calculating the primary energies. It will be used together with the observed muon content (ratio of muons to all particles), to draw conclusions about the nature of the primary particles.
124991249
Particle astrophysics in antarctica
15505534
On the difference between Herbig Ae and Herbig Be stars
We present linear spectropolarimetric data for eight Herbig Be and four Herbig Ae stars at Hα ,H β and Hγ . Changes in the linear polarization are detected across all Balmer lines for a large fraction of the observed objects, confirming that the small-scale regions surrounding these objects are flattened (i.e. disc-like). Furthermore, all objects with detections show similar characteristics at the three spectral lines, despite differences in transition probability and optical depth going from Hα to Hγ . A large fraction of early Herbig Be stars (B0‐B3) observed show line-depolarization effects. However, the early Herbig Ae stars (A0‐A2), observed for comparison, show intrinsic line-polarization signatures. Our data suggest that the popular magnetic accretion scenario for T Tauri objects may be extended to Herbig Ae stars, but that it may not be extended to early Herbig Be stars, for which the available data are consistent with disc accretion.
13621763
What are sterile neutrinos good for
Taken at face value, current experimental data indicate the existence of a new particle, the sterile neutrino, which must be a singlet under the Standard Model gauge group. Although they are not detectable through traditional means, such particles have interesting observable consequences for particle astrophysics and cosmology. Here we examine these implications and discuss, in particular, sterile neutrino dark matter and the relationship between matter-enhanced active-sterile neutrino transformation and the synthesis of heavy elements in supernovae.
118055934
Summary of the CKM 2010 Working Group on Rare Decays
Rare decays were essential in the discovery of the CKM mechanism of flavour and CP violation and are highly sensitive probes of physics beyond the Standard Model. In this summary the current status and future prospects of experimental measurements and the Standard Model theory predictions of various rare B, D and K decay observables are discussed. The specific new physics sensitivities of each mode are also briefly reviewed.
121744643
Characterisation and compensation of magnetic distortions for the pixel Hybrid Photon Detectors of the LHCb RICH
Abstract The LHCb experiment at LHC, optimised for the study of CP violation, has two RICH detectors to provide particle identification in the momentum range ∼ 2 – 100 GeV / c . The stringent requirements on the photon detectors are met by the custom-made pixel Hybrid Photon Detector. The photon detectors need to operate in the fringe field of the LHCb dipole magnet which will produce distortions of the image detected on the pixel chip which is encapsulated inside the HPD. This paper reports on the experimental characterisation of the image distortions caused by an external magnetic flux density. These measurements allow for the development of a parameterisation of the effects and a compensation algorithm, which are also presented.
119418934
ANALYSIS OF TEST-BEAM DATA FROM A PROTOTYPE LHCB RICH DETECTOR